hb/public/static/plug/codemirror/lib/codemirror.js

// CodeMirror, copyright (c) by Marijn Haverbeke and others
// Distributed under an MIT license: https://codemirror.net/LICENSE

// This is CodeMirror (https://codemirror.net), a code editor
// implemented in JavaScript on top of the browser's DOM.
//
// You can find some technical background for some of the code below
// at http://marijnhaverbeke.nl/blog/#cm-internals .

(function (global, factory) {
  typeof exports === 'object' && typeof module !== 'undefined' ? module.exports = factory() :
  typeof define === 'function' && define.amd ? define(factory) :
  (global.CodeMirror = factory());
}(this, (function () { 'use strict';

// Kludges for bugs and behavior differences that can't be feature
// detected are enabled based on userAgent etc sniffing.
var userAgent = navigator.userAgent
var platform = navigator.platform

var gecko = /gecko\/\d/i.test(userAgent)
var ie_upto10 = /MSIE \d/.test(userAgent)
var ie_11up = /Trident\/(?:[7-9]|\d{2,})\..*rv:(\d+)/.exec(userAgent)
var edge = /Edge\/(\d+)/.exec(userAgent)
var ie = ie_upto10 || ie_11up || edge
var ie_version = ie && (ie_upto10 ? document.documentMode || 6 : +(edge || ie_11up)[1])
var webkit = !edge && /WebKit\//.test(userAgent)
var qtwebkit = webkit && /Qt\/\d+\.\d+/.test(userAgent)
var chrome = !edge && /Chrome\//.test(userAgent)
var presto = /Opera\//.test(userAgent)
var safari = /Apple Computer/.test(navigator.vendor)
var mac_geMountainLion = /Mac OS X 1\d\D([8-9]|\d\d)\D/.test(userAgent)
var phantom = /PhantomJS/.test(userAgent)

var ios = !edge && /AppleWebKit/.test(userAgent) && /Mobile\/\w+/.test(userAgent)
var android = /Android/.test(userAgent)
// This is woefully incomplete. Suggestions for alternative methods welcome.
var mobile = ios || android || /webOS|BlackBerry|Opera Mini|Opera Mobi|IEMobile/i.test(userAgent)
var mac = ios || /Mac/.test(platform)
var chromeOS = /\bCrOS\b/.test(userAgent)
var windows = /win/i.test(platform)

var presto_version = presto && userAgent.match(/Version\/(\d*\.\d*)/)
if (presto_version) { presto_version = Number(presto_version[1]) }
if (presto_version && presto_version >= 15) { presto = false; webkit = true }
// Some browsers use the wrong event properties to signal cmd/ctrl on OS X
var flipCtrlCmd = mac && (qtwebkit || presto && (presto_version == null || presto_version < 12.11))
var captureRightClick = gecko || (ie && ie_version >= 9)

function classTest(cls) { return new RegExp("(^|\\s)" + cls + "(?:$|\\s)\\s*") }

var rmClass = function(node, cls) {
  var current = node.className
  var match = classTest(cls).exec(current)
  if (match) {
    var after = current.slice(match.index + match[0].length)
    node.className = current.slice(0, match.index) + (after ? match[1] + after : "")
  }
}

function removeChildren(e) {
  for (var count = e.childNodes.length; count > 0; --count)
    { e.removeChild(e.firstChild) }
  return e
}

function removeChildrenAndAdd(parent, e) {
  return removeChildren(parent).appendChild(e)
}

function elt(tag, content, className, style) {
  var e = document.createElement(tag)
  if (className) { e.className = className }
  if (style) { e.style.cssText = style }
  if (typeof content == "string") { e.appendChild(document.createTextNode(content)) }
  else if (content) { for (var i = 0; i < content.length; ++i) { e.appendChild(content[i]) } }
  return e
}
// wrapper for elt, which removes the elt from the accessibility tree
function eltP(tag, content, className, style) {
  var e = elt(tag, content, className, style)
  e.setAttribute("role", "presentation")
  return e
}

var range
if (document.createRange) { range = function(node, start, end, endNode) {
  var r = document.createRange()
  r.setEnd(endNode || node, end)
  r.setStart(node, start)
  return r
} }
else { range = function(node, start, end) {
  var r = document.body.createTextRange()
  try { r.moveToElementText(node.parentNode) }
  catch(e) { return r }
  r.collapse(true)
  r.moveEnd("character", end)
  r.moveStart("character", start)
  return r
} }

function contains(parent, child) {
  if (child.nodeType == 3) // Android browser always returns false when child is a textnode
    { child = child.parentNode }
  if (parent.contains)
    { return parent.contains(child) }
  do {
    if (child.nodeType == 11) { child = child.host }
    if (child == parent) { return true }
  } while (child = child.parentNode)
}

function activeElt() {
  // IE and Edge may throw an "Unspecified Error" when accessing document.activeElement.
  // IE < 10 will throw when accessed while the page is loading or in an iframe.
  // IE > 9 and Edge will throw when accessed in an iframe if document.body is unavailable.
  var activeElement
  try {
    activeElement = document.activeElement
  } catch(e) {
    activeElement = document.body || null
  }
  while (activeElement && activeElement.shadowRoot && activeElement.shadowRoot.activeElement)
    { activeElement = activeElement.shadowRoot.activeElement }
  return activeElement
}

function addClass(node, cls) {
  var current = node.className
  if (!classTest(cls).test(current)) { node.className += (current ? " " : "") + cls }
}
function joinClasses(a, b) {
  var as = a.split(" ")
  for (var i = 0; i < as.length; i++)
    { if (as[i] && !classTest(as[i]).test(b)) { b += " " + as[i] } }
  return b
}

var selectInput = function(node) { node.select() }
if (ios) // Mobile Safari apparently has a bug where select() is broken.
  { selectInput = function(node) { node.selectionStart = 0; node.selectionEnd = node.value.length } }
else if (ie) // Suppress mysterious IE10 errors
  { selectInput = function(node) { try { node.select() } catch(_e) {} } }

function bind(f) {
  var args = Array.prototype.slice.call(arguments, 1)
  return function(){return f.apply(null, args)}
}

function copyObj(obj, target, overwrite) {
  if (!target) { target = {} }
  for (var prop in obj)
    { if (obj.hasOwnProperty(prop) && (overwrite !== false || !target.hasOwnProperty(prop)))
      { target[prop] = obj[prop] } }
  return target
}

// Counts the column offset in a string, taking tabs into account.
// Used mostly to find indentation.
function countColumn(string, end, tabSize, startIndex, startValue) {
  if (end == null) {
    end = string.search(/[^\s\u00a0]/)
    if (end == -1) { end = string.length }
  }
  for (var i = startIndex || 0, n = startValue || 0;;) {
    var nextTab = string.indexOf("\t", i)
    if (nextTab < 0 || nextTab >= end)
      { return n + (end - i) }
    n += nextTab - i
    n += tabSize - (n % tabSize)
    i = nextTab + 1
  }
}

var Delayed = function() {this.id = null};
Delayed.prototype.set = function (ms, f) {
  clearTimeout(this.id)
  this.id = setTimeout(f, ms)
};

function indexOf(array, elt) {
  for (var i = 0; i < array.length; ++i)
    { if (array[i] == elt) { return i } }
  return -1
}

// Number of pixels added to scroller and sizer to hide scrollbar
var scrollerGap = 30

// Returned or thrown by various protocols to signal 'I'm not
// handling this'.
var Pass = {toString: function(){return "CodeMirror.Pass"}}

// Reused option objects for setSelection & friends
var sel_dontScroll = {scroll: false};
var sel_mouse = {origin: "*mouse"};
var sel_move = {origin: "+move"};
// The inverse of countColumn -- find the offset that corresponds to
// a particular column.
function findColumn(string, goal, tabSize) {
  for (var pos = 0, col = 0;;) {
    var nextTab = string.indexOf("\t", pos)
    if (nextTab == -1) { nextTab = string.length }
    var skipped = nextTab - pos
    if (nextTab == string.length || col + skipped >= goal)
      { return pos + Math.min(skipped, goal - col) }
    col += nextTab - pos
    col += tabSize - (col % tabSize)
    pos = nextTab + 1
    if (col >= goal) { return pos }
  }
}

var spaceStrs = [""]
function spaceStr(n) {
  while (spaceStrs.length <= n)
    { spaceStrs.push(lst(spaceStrs) + " ") }
  return spaceStrs[n]
}

function lst(arr) { return arr[arr.length-1] }

function map(array, f) {
  var out = []
  for (var i = 0; i < array.length; i++) { out[i] = f(array[i], i) }
  return out
}

function insertSorted(array, value, score) {
  var pos = 0, priority = score(value)
  while (pos < array.length && score(array[pos]) <= priority) { pos++ }
  array.splice(pos, 0, value)
}

function nothing() {}

function createObj(base, props) {
  var inst
  if (Object.create) {
    inst = Object.create(base)
  } else {
    nothing.prototype = base
    inst = new nothing()
  }
  if (props) { copyObj(props, inst) }
  return inst
}

var nonASCIISingleCaseWordChar = /[\u00df\u0587\u0590-\u05f4\u0600-\u06ff\u3040-\u309f\u30a0-\u30ff\u3400-\u4db5\u4e00-\u9fcc\uac00-\ud7af]/
function isWordCharBasic(ch) {
  return /\w/.test(ch) || ch > "\x80" &&
    (ch.toUpperCase() != ch.toLowerCase() || nonASCIISingleCaseWordChar.test(ch))
}
function isWordChar(ch, helper) {
  if (!helper) { return isWordCharBasic(ch) }
  if (helper.source.indexOf("\\w") > -1 && isWordCharBasic(ch)) { return true }
  return helper.test(ch)
}

function isEmpty(obj) {
  for (var n in obj) { if (obj.hasOwnProperty(n) && obj[n]) { return false } }
  return true
}

// Extending unicode characters. A series of a non-extending char +
// any number of extending chars is treated as a single unit as far
// as editing and measuring is concerned. This is not fully correct,
// since some scripts/fonts/browsers also treat other configurations
// of code points as a group.
var extendingChars = /[\u0300-\u036f\u0483-\u0489\u0591-\u05bd\u05bf\u05c1\u05c2\u05c4\u05c5\u05c7\u0610-\u061a\u064b-\u065e\u0670\u06d6-\u06dc\u06de-\u06e4\u06e7\u06e8\u06ea-\u06ed\u0711\u0730-\u074a\u07a6-\u07b0\u07eb-\u07f3\u0816-\u0819\u081b-\u0823\u0825-\u0827\u0829-\u082d\u0900-\u0902\u093c\u0941-\u0948\u094d\u0951-\u0955\u0962\u0963\u0981\u09bc\u09be\u09c1-\u09c4\u09cd\u09d7\u09e2\u09e3\u0a01\u0a02\u0a3c\u0a41\u0a42\u0a47\u0a48\u0a4b-\u0a4d\u0a51\u0a70\u0a71\u0a75\u0a81\u0a82\u0abc\u0ac1-\u0ac5\u0ac7\u0ac8\u0acd\u0ae2\u0ae3\u0b01\u0b3c\u0b3e\u0b3f\u0b41-\u0b44\u0b4d\u0b56\u0b57\u0b62\u0b63\u0b82\u0bbe\u0bc0\u0bcd\u0bd7\u0c3e-\u0c40\u0c46-\u0c48\u0c4a-\u0c4d\u0c55\u0c56\u0c62\u0c63\u0cbc\u0cbf\u0cc2\u0cc6\u0ccc\u0ccd\u0cd5\u0cd6\u0ce2\u0ce3\u0d3e\u0d41-\u0d44\u0d4d\u0d57\u0d62\u0d63\u0dca\u0dcf\u0dd2-\u0dd4\u0dd6\u0ddf\u0e31\u0e34-\u0e3a\u0e47-\u0e4e\u0eb1\u0eb4-\u0eb9\u0ebb\u0ebc\u0ec8-\u0ecd\u0f18\u0f19\u0f35\u0f37\u0f39\u0f71-\u0f7e\u0f80-\u0f84\u0f86\u0f87\u0f90-\u0f97\u0f99-\u0fbc\u0fc6\u102d-\u1030\u1032-\u1037\u1039\u103a\u103d\u103e\u1058\u1059\u105e-\u1060\u1071-\u1074\u1082\u1085\u1086\u108d\u109d\u135f\u1712-\u1714\u1732-\u1734\u1752\u1753\u1772\u1773\u17b7-\u17bd\u17c6\u17c9-\u17d3\u17dd\u180b-\u180d\u18a9\u1920-\u1922\u1927\u1928\u1932\u1939-\u193b\u1a17\u1a18\u1a56\u1a58-\u1a5e\u1a60\u1a62\u1a65-\u1a6c\u1a73-\u1a7c\u1a7f\u1b00-\u1b03\u1b34\u1b36-\u1b3a\u1b3c\u1b42\u1b6b-\u1b73\u1b80\u1b81\u1ba2-\u1ba5\u1ba8\u1ba9\u1c2c-\u1c33\u1c36\u1c37\u1cd0-\u1cd2\u1cd4-\u1ce0\u1ce2-\u1ce8\u1ced\u1dc0-\u1de6\u1dfd-\u1dff\u200c\u200d\u20d0-\u20f0\u2cef-\u2cf1\u2de0-\u2dff\u302a-\u302f\u3099\u309a\ua66f-\ua672\ua67c\ua67d\ua6f0\ua6f1\ua802\ua806\ua80b\ua825\ua826\ua8c4\ua8e0-\ua8f1\ua926-\ua92d\ua947-\ua951\ua980-\ua982\ua9b3\ua9b6-\ua9b9\ua9bc\uaa29-\uaa2e\uaa31\uaa32\uaa35\uaa36\uaa43\uaa4c\uaab0\uaab2-\uaab4\uaab7\uaab8\uaabe\uaabf\uaac1\uabe5\uabe8\uabed\udc00-\udfff\ufb1e\ufe00-\ufe0f\ufe20-\ufe26\uff9e\uff9f]/
function isExtendingChar(ch) { return ch.charCodeAt(0) >= 768 && extendingChars.test(ch) }

// Returns a number from the range [`0`; `str.length`] unless `pos` is outside that range.
function skipExtendingChars(str, pos, dir) {
  while ((dir < 0 ? pos > 0 : pos < str.length) && isExtendingChar(str.charAt(pos))) { pos += dir }
  return pos
}

// Returns the value from the range [`from`; `to`] that satisfies
// `pred` and is closest to `from`. Assumes that at least `to`
// satisfies `pred`. Supports `from` being greater than `to`.
function findFirst(pred, from, to) {
  // At any point we are certain `to` satisfies `pred`, don't know
  // whether `from` does.
  var dir = from > to ? -1 : 1
  for (;;) {
    if (from == to) { return from }
    var midF = (from + to) / 2, mid = dir < 0 ? Math.ceil(midF) : Math.floor(midF)
    if (mid == from) { return pred(mid) ? from : to }
    if (pred(mid)) { to = mid }
    else { from = mid + dir }
  }
}

// The display handles the DOM integration, both for input reading
// and content drawing. It holds references to DOM nodes and
// display-related state.

function Display(place, doc, input) {
  var d = this
  this.input = input

  // Covers bottom-right square when both scrollbars are present.
  d.scrollbarFiller = elt("div", null, "CodeMirror-scrollbar-filler")
  d.scrollbarFiller.setAttribute("cm-not-content", "true")
  // Covers bottom of gutter when coverGutterNextToScrollbar is on
  // and h scrollbar is present.
  d.gutterFiller = elt("div", null, "CodeMirror-gutter-filler")
  d.gutterFiller.setAttribute("cm-not-content", "true")
  // Will contain the actual code, positioned to cover the viewport.
  d.lineDiv = eltP("div", null, "CodeMirror-code")
  // Elements are added to these to represent selection and cursors.
  d.selectionDiv = elt("div", null, null, "position: relative; z-index: 1")
  d.cursorDiv = elt("div", null, "CodeMirror-cursors")
  // A visibility: hidden element used to find the size of things.
  d.measure = elt("div", null, "CodeMirror-measure")
  // When lines outside of the viewport are measured, they are drawn in this.
  d.lineMeasure = elt("div", null, "CodeMirror-measure")
  // Wraps everything that needs to exist inside the vertically-padded coordinate system
  d.lineSpace = eltP("div", [d.measure, d.lineMeasure, d.selectionDiv, d.cursorDiv, d.lineDiv],
                    null, "position: relative; outline: none")
  var lines = eltP("div", [d.lineSpace], "CodeMirror-lines")
  // Moved around its parent to cover visible view.
  d.mover = elt("div", [lines], null, "position: relative")
  // Set to the height of the document, allowing scrolling.
  d.sizer = elt("div", [d.mover], "CodeMirror-sizer")
  d.sizerWidth = null
  // Behavior of elts with overflow: auto and padding is
  // inconsistent across browsers. This is used to ensure the
  // scrollable area is big enough.
  d.heightForcer = elt("div", null, null, "position: absolute; height: " + scrollerGap + "px; width: 1px;")
  // Will contain the gutters, if any.
  d.gutters = elt("div", null, "CodeMirror-gutters")
  d.lineGutter = null
  // Actual scrollable element.
  d.scroller = elt("div", [d.sizer, d.heightForcer, d.gutters], "CodeMirror-scroll")
  d.scroller.setAttribute("tabIndex", "-1")
  // The element in which the editor lives.
  d.wrapper = elt("div", [d.scrollbarFiller, d.gutterFiller, d.scroller], "CodeMirror")

  // Work around IE7 z-index bug (not perfect, hence IE7 not really being supported)
  if (ie && ie_version < 8) { d.gutters.style.zIndex = -1; d.scroller.style.paddingRight = 0 }
  if (!webkit && !(gecko && mobile)) { d.scroller.draggable = true }

  if (place) {
    if (place.appendChild) { place.appendChild(d.wrapper) }
    else { place(d.wrapper) }
  }

  // Current rendered range (may be bigger than the view window).
  d.viewFrom = d.viewTo = doc.first
  d.reportedViewFrom = d.reportedViewTo = doc.first
  // Information about the rendered lines.
  d.view = []
  d.renderedView = null
  // Holds info about a single rendered line when it was rendered
  // for measurement, while not in view.
  d.externalMeasured = null
  // Empty space (in pixels) above the view
  d.viewOffset = 0
  d.lastWrapHeight = d.lastWrapWidth = 0
  d.updateLineNumbers = null

  d.nativeBarWidth = d.barHeight = d.barWidth = 0
  d.scrollbarsClipped = false

  // Used to only resize the line number gutter when necessary (when
  // the amount of lines crosses a boundary that makes its width change)
  d.lineNumWidth = d.lineNumInnerWidth = d.lineNumChars = null
  // Set to true when a non-horizontal-scrolling line widget is
  // added. As an optimization, line widget aligning is skipped when
  // this is false.
  d.alignWidgets = false

  d.cachedCharWidth = d.cachedTextHeight = d.cachedPaddingH = null

  // Tracks the maximum line length so that the horizontal scrollbar
  // can be kept static when scrolling.
  d.maxLine = null
  d.maxLineLength = 0
  d.maxLineChanged = false

  // Used for measuring wheel scrolling granularity
  d.wheelDX = d.wheelDY = d.wheelStartX = d.wheelStartY = null

  // True when shift is held down.
  d.shift = false

  // Used to track whether anything happened since the context menu
  // was opened.
  d.selForContextMenu = null

  d.activeTouch = null

  input.init(d)
}

// Find the line object corresponding to the given line number.
function getLine(doc, n) {
  n -= doc.first
  if (n < 0 || n >= doc.size) { throw new Error("There is no line " + (n + doc.first) + " in the document.") }
  var chunk = doc
  while (!chunk.lines) {
    for (var i = 0;; ++i) {
      var child = chunk.children[i], sz = child.chunkSize()
      if (n < sz) { chunk = child; break }
      n -= sz
    }
  }
  return chunk.lines[n]
}

// Get the part of a document between two positions, as an array of
// strings.
function getBetween(doc, start, end) {
  var out = [], n = start.line
  doc.iter(start.line, end.line + 1, function (line) {
    var text = line.text
    if (n == end.line) { text = text.slice(0, end.ch) }
    if (n == start.line) { text = text.slice(start.ch) }
    out.push(text)
    ++n
  })
  return out
}
// Get the lines between from and to, as array of strings.
function getLines(doc, from, to) {
  var out = []
  doc.iter(from, to, function (line) { out.push(line.text) }) // iter aborts when callback returns truthy value
  return out
}

// Update the height of a line, propagating the height change
// upwards to parent nodes.
function updateLineHeight(line, height) {
  var diff = height - line.height
  if (diff) { for (var n = line; n; n = n.parent) { n.height += diff } }
}

// Given a line object, find its line number by walking up through
// its parent links.
function lineNo(line) {
  if (line.parent == null) { return null }
  var cur = line.parent, no = indexOf(cur.lines, line)
  for (var chunk = cur.parent; chunk; cur = chunk, chunk = chunk.parent) {
    for (var i = 0;; ++i) {
      if (chunk.children[i] == cur) { break }
      no += chunk.children[i].chunkSize()
    }
  }
  return no + cur.first
}

// Find the line at the given vertical position, using the height
// information in the document tree.
function lineAtHeight(chunk, h) {
  var n = chunk.first
  outer: do {
    for (var i$1 = 0; i$1 < chunk.children.length; ++i$1) {
      var child = chunk.children[i$1], ch = child.height
      if (h < ch) { chunk = child; continue outer }
      h -= ch
      n += child.chunkSize()
    }
    return n
  } while (!chunk.lines)
  var i = 0
  for (; i < chunk.lines.length; ++i) {
    var line = chunk.lines[i], lh = line.height
    if (h < lh) { break }
    h -= lh
  }
  return n + i
}

function isLine(doc, l) {return l >= doc.first && l < doc.first + doc.size}

function lineNumberFor(options, i) {
  return String(options.lineNumberFormatter(i + options.firstLineNumber))
}

// A Pos instance represents a position within the text.
function Pos(line, ch, sticky) {
  if ( sticky === void 0 ) sticky = null;

  if (!(this instanceof Pos)) { return new Pos(line, ch, sticky) }
  this.line = line
  this.ch = ch
  this.sticky = sticky
}

// Compare two positions, return 0 if they are the same, a negative
// number when a is less, and a positive number otherwise.
function cmp(a, b) { return a.line - b.line || a.ch - b.ch }

function equalCursorPos(a, b) { return a.sticky == b.sticky && cmp(a, b) == 0 }

function copyPos(x) {return Pos(x.line, x.ch)}
function maxPos(a, b) { return cmp(a, b) < 0 ? b : a }
function minPos(a, b) { return cmp(a, b) < 0 ? a : b }

// Most of the external API clips given positions to make sure they
// actually exist within the document.
function clipLine(doc, n) {return Math.max(doc.first, Math.min(n, doc.first + doc.size - 1))}
function clipPos(doc, pos) {
  if (pos.line < doc.first) { return Pos(doc.first, 0) }
  var last = doc.first + doc.size - 1
  if (pos.line > last) { return Pos(last, getLine(doc, last).text.length) }
  return clipToLen(pos, getLine(doc, pos.line).text.length)
}
function clipToLen(pos, linelen) {
  var ch = pos.ch
  if (ch == null || ch > linelen) { return Pos(pos.line, linelen) }
  else if (ch < 0) { return Pos(pos.line, 0) }
  else { return pos }
}
function clipPosArray(doc, array) {
  var out = []
  for (var i = 0; i < array.length; i++) { out[i] = clipPos(doc, array[i]) }
  return out
}

// Optimize some code when these features are not used.
var sawReadOnlySpans = false;
var sawCollapsedSpans = false;
function seeReadOnlySpans() {
  sawReadOnlySpans = true
}

function seeCollapsedSpans() {
  sawCollapsedSpans = true
}

// TEXTMARKER SPANS

function MarkedSpan(marker, from, to) {
  this.marker = marker
  this.from = from; this.to = to
}

// Search an array of spans for a span matching the given marker.
function getMarkedSpanFor(spans, marker) {
  if (spans) { for (var i = 0; i < spans.length; ++i) {
    var span = spans[i]
    if (span.marker == marker) { return span }
  } }
}
// Remove a span from an array, returning undefined if no spans are
// left (we don't store arrays for lines without spans).
function removeMarkedSpan(spans, span) {
  var r
  for (var i = 0; i < spans.length; ++i)
    { if (spans[i] != span) { (r || (r = [])).push(spans[i]) } }
  return r
}
// Add a span to a line.
function addMarkedSpan(line, span) {
  line.markedSpans = line.markedSpans ? line.markedSpans.concat([span]) : [span]
  span.marker.attachLine(line)
}

// Used for the algorithm that adjusts markers for a change in the
// document. These functions cut an array of spans at a given
// character position, returning an array of remaining chunks (or
// undefined if nothing remains).
function markedSpansBefore(old, startCh, isInsert) {
  var nw
  if (old) { for (var i = 0; i < old.length; ++i) {
    var span = old[i], marker = span.marker
    var startsBefore = span.from == null || (marker.inclusiveLeft ? span.from <= startCh : span.from < startCh)
    if (startsBefore || span.from == startCh && marker.type == "bookmark" && (!isInsert || !span.marker.insertLeft)) {
      var endsAfter = span.to == null || (marker.inclusiveRight ? span.to >= startCh : span.to > startCh)
      ;(nw || (nw = [])).push(new MarkedSpan(marker, span.from, endsAfter ? null : span.to))
    }
  } }
  return nw
}
function markedSpansAfter(old, endCh, isInsert) {
  var nw
  if (old) { for (var i = 0; i < old.length; ++i) {
    var span = old[i], marker = span.marker
    var endsAfter = span.to == null || (marker.inclusiveRight ? span.to >= endCh : span.to > endCh)
    if (endsAfter || span.from == endCh && marker.type == "bookmark" && (!isInsert || span.marker.insertLeft)) {
      var startsBefore = span.from == null || (marker.inclusiveLeft ? span.from <= endCh : span.from < endCh)
      ;(nw || (nw = [])).push(new MarkedSpan(marker, startsBefore ? null : span.from - endCh,
                                            span.to == null ? null : span.to - endCh))
    }
  } }
  return nw
}

// Given a change object, compute the new set of marker spans that
// cover the line in which the change took place. Removes spans
// entirely within the change, reconnects spans belonging to the
// same marker that appear on both sides of the change, and cuts off
// spans partially within the change. Returns an array of span
// arrays with one element for each line in (after) the change.
function stretchSpansOverChange(doc, change) {
  if (change.full) { return null }
  var oldFirst = isLine(doc, change.from.line) && getLine(doc, change.from.line).markedSpans
  var oldLast = isLine(doc, change.to.line) && getLine(doc, change.to.line).markedSpans
  if (!oldFirst && !oldLast) { return null }

  var startCh = change.from.ch, endCh = change.to.ch, isInsert = cmp(change.from, change.to) == 0
  // Get the spans that 'stick out' on both sides
  var first = markedSpansBefore(oldFirst, startCh, isInsert)
  var last = markedSpansAfter(oldLast, endCh, isInsert)

  // Next, merge those two ends
  var sameLine = change.text.length == 1, offset = lst(change.text).length + (sameLine ? startCh : 0)
  if (first) {
    // Fix up .to properties of first
    for (var i = 0; i < first.length; ++i) {
      var span = first[i]
      if (span.to == null) {
        var found = getMarkedSpanFor(last, span.marker)
        if (!found) { span.to = startCh }
        else if (sameLine) { span.to = found.to == null ? null : found.to + offset }
      }
    }
  }
  if (last) {
    // Fix up .from in last (or move them into first in case of sameLine)
    for (var i$1 = 0; i$1 < last.length; ++i$1) {
      var span$1 = last[i$1]
      if (span$1.to != null) { span$1.to += offset }
      if (span$1.from == null) {
        var found$1 = getMarkedSpanFor(first, span$1.marker)
        if (!found$1) {
          span$1.from = offset
          if (sameLine) { (first || (first = [])).push(span$1) }
        }
      } else {
        span$1.from += offset
        if (sameLine) { (first || (first = [])).push(span$1) }
      }
    }
  }
  // Make sure we didn't create any zero-length spans
  if (first) { first = clearEmptySpans(first) }
  if (last && last != first) { last = clearEmptySpans(last) }

  var newMarkers = [first]
  if (!sameLine) {
    // Fill gap with whole-line-spans
    var gap = change.text.length - 2, gapMarkers
    if (gap > 0 && first)
      { for (var i$2 = 0; i$2 < first.length; ++i$2)
        { if (first[i$2].to == null)
          { (gapMarkers || (gapMarkers = [])).push(new MarkedSpan(first[i$2].marker, null, null)) } } }
    for (var i$3 = 0; i$3 < gap; ++i$3)
      { newMarkers.push(gapMarkers) }
    newMarkers.push(last)
  }
  return newMarkers
}

// Remove spans that are empty and don't have a clearWhenEmpty
// option of false.
function clearEmptySpans(spans) {
  for (var i = 0; i < spans.length; ++i) {
    var span = spans[i]
    if (span.from != null && span.from == span.to && span.marker.clearWhenEmpty !== false)
      { spans.splice(i--, 1) }
  }
  if (!spans.length) { return null }
  return spans
}

// Used to 'clip' out readOnly ranges when making a change.
function removeReadOnlyRanges(doc, from, to) {
  var markers = null
  doc.iter(from.line, to.line + 1, function (line) {
    if (line.markedSpans) { for (var i = 0; i < line.markedSpans.length; ++i) {
      var mark = line.markedSpans[i].marker
      if (mark.readOnly && (!markers || indexOf(markers, mark) == -1))
        { (markers || (markers = [])).push(mark) }
    } }
  })
  if (!markers) { return null }
  var parts = [{from: from, to: to}]
  for (var i = 0; i < markers.length; ++i) {
    var mk = markers[i], m = mk.find(0)
    for (var j = 0; j < parts.length; ++j) {
      var p = parts[j]
      if (cmp(p.to, m.from) < 0 || cmp(p.from, m.to) > 0) { continue }
      var newParts = [j, 1], dfrom = cmp(p.from, m.from), dto = cmp(p.to, m.to)
      if (dfrom < 0 || !mk.inclusiveLeft && !dfrom)
        { newParts.push({from: p.from, to: m.from}) }
      if (dto > 0 || !mk.inclusiveRight && !dto)
        { newParts.push({from: m.to, to: p.to}) }
      parts.splice.apply(parts, newParts)
      j += newParts.length - 3
    }
  }
  return parts
}

// Connect or disconnect spans from a line.
function detachMarkedSpans(line) {
  var spans = line.markedSpans
  if (!spans) { return }
  for (var i = 0; i < spans.length; ++i)
    { spans[i].marker.detachLine(line) }
  line.markedSpans = null
}
function attachMarkedSpans(line, spans) {
  if (!spans) { return }
  for (var i = 0; i < spans.length; ++i)
    { spans[i].marker.attachLine(line) }
  line.markedSpans = spans
}

// Helpers used when computing which overlapping collapsed span
// counts as the larger one.
function extraLeft(marker) { return marker.inclusiveLeft ? -1 : 0 }
function extraRight(marker) { return marker.inclusiveRight ? 1 : 0 }

// Returns a number indicating which of two overlapping collapsed
// spans is larger (and thus includes the other). Falls back to
// comparing ids when the spans cover exactly the same range.
function compareCollapsedMarkers(a, b) {
  var lenDiff = a.lines.length - b.lines.length
  if (lenDiff != 0) { return lenDiff }
  var aPos = a.find(), bPos = b.find()
  var fromCmp = cmp(aPos.from, bPos.from) || extraLeft(a) - extraLeft(b)
  if (fromCmp) { return -fromCmp }
  var toCmp = cmp(aPos.to, bPos.to) || extraRight(a) - extraRight(b)
  if (toCmp) { return toCmp }
  return b.id - a.id
}

// Find out whether a line ends or starts in a collapsed span. If
// so, return the marker for that span.
function collapsedSpanAtSide(line, start) {
  var sps = sawCollapsedSpans && line.markedSpans, found
  if (sps) { for (var sp = (void 0), i = 0; i < sps.length; ++i) {
    sp = sps[i]
    if (sp.marker.collapsed && (start ? sp.from : sp.to) == null &&
        (!found || compareCollapsedMarkers(found, sp.marker) < 0))
      { found = sp.marker }
  } }
  return found
}
function collapsedSpanAtStart(line) { return collapsedSpanAtSide(line, true) }
function collapsedSpanAtEnd(line) { return collapsedSpanAtSide(line, false) }

function collapsedSpanAround(line, ch) {
  var sps = sawCollapsedSpans && line.markedSpans, found
  if (sps) { for (var i = 0; i < sps.length; ++i) {
    var sp = sps[i]
    if (sp.marker.collapsed && (sp.from == null || sp.from < ch) && (sp.to == null || sp.to > ch) &&
        (!found || compareCollapsedMarkers(found, sp.marker) < 0)) { found = sp.marker }
  } }
  return found
}

// Test whether there exists a collapsed span that partially
// overlaps (covers the start or end, but not both) of a new span.
// Such overlap is not allowed.
function conflictingCollapsedRange(doc, lineNo, from, to, marker) {
  var line = getLine(doc, lineNo)
  var sps = sawCollapsedSpans && line.markedSpans
  if (sps) { for (var i = 0; i < sps.length; ++i) {
    var sp = sps[i]
    if (!sp.marker.collapsed) { continue }
    var found = sp.marker.find(0)
    var fromCmp = cmp(found.from, from) || extraLeft(sp.marker) - extraLeft(marker)
    var toCmp = cmp(found.to, to) || extraRight(sp.marker) - extraRight(marker)
    if (fromCmp >= 0 && toCmp <= 0 || fromCmp <= 0 && toCmp >= 0) { continue }
    if (fromCmp <= 0 && (sp.marker.inclusiveRight && marker.inclusiveLeft ? cmp(found.to, from) >= 0 : cmp(found.to, from) > 0) ||
        fromCmp >= 0 && (sp.marker.inclusiveRight && marker.inclusiveLeft ? cmp(found.from, to) <= 0 : cmp(found.from, to) < 0))
      { return true }
  } }
}

// A visual line is a line as drawn on the screen. Folding, for
// example, can cause multiple logical lines to appear on the same
// visual line. This finds the start of the visual line that the
// given line is part of (usually that is the line itself).
function visualLine(line) {
  var merged
  while (merged = collapsedSpanAtStart(line))
    { line = merged.find(-1, true).line }
  return line
}

function visualLineEnd(line) {
  var merged
  while (merged = collapsedSpanAtEnd(line))
    { line = merged.find(1, true).line }
  return line
}

// Returns an array of logical lines that continue the visual line
// started by the argument, or undefined if there are no such lines.
function visualLineContinued(line) {
  var merged, lines
  while (merged = collapsedSpanAtEnd(line)) {
    line = merged.find(1, true).line
    ;(lines || (lines = [])).push(line)
  }
  return lines
}

// Get the line number of the start of the visual line that the
// given line number is part of.
function visualLineNo(doc, lineN) {
  var line = getLine(doc, lineN), vis = visualLine(line)
  if (line == vis) { return lineN }
  return lineNo(vis)
}

// Get the line number of the start of the next visual line after
// the given line.
function visualLineEndNo(doc, lineN) {
  if (lineN > doc.lastLine()) { return lineN }
  var line = getLine(doc, lineN), merged
  if (!lineIsHidden(doc, line)) { return lineN }
  while (merged = collapsedSpanAtEnd(line))
    { line = merged.find(1, true).line }
  return lineNo(line) + 1
}

// Compute whether a line is hidden. Lines count as hidden when they
// are part of a visual line that starts with another line, or when
// they are entirely covered by collapsed, non-widget span.
function lineIsHidden(doc, line) {
  var sps = sawCollapsedSpans && line.markedSpans
  if (sps) { for (var sp = (void 0), i = 0; i < sps.length; ++i) {
    sp = sps[i]
    if (!sp.marker.collapsed) { continue }
    if (sp.from == null) { return true }
    if (sp.marker.widgetNode) { continue }
    if (sp.from == 0 && sp.marker.inclusiveLeft && lineIsHiddenInner(doc, line, sp))
      { return true }
  } }
}
function lineIsHiddenInner(doc, line, span) {
  if (span.to == null) {
    var end = span.marker.find(1, true)
    return lineIsHiddenInner(doc, end.line, getMarkedSpanFor(end.line.markedSpans, span.marker))
  }
  if (span.marker.inclusiveRight && span.to == line.text.length)
    { return true }
  for (var sp = (void 0), i = 0; i < line.markedSpans.length; ++i) {
    sp = line.markedSpans[i]
    if (sp.marker.collapsed && !sp.marker.widgetNode && sp.from == span.to &&
        (sp.to == null || sp.to != span.from) &&
        (sp.marker.inclusiveLeft || span.marker.inclusiveRight) &&
        lineIsHiddenInner(doc, line, sp)) { return true }
  }
}

// Find the height above the given line.
function heightAtLine(lineObj) {
  lineObj = visualLine(lineObj)

  var h = 0, chunk = lineObj.parent
  for (var i = 0; i < chunk.lines.length; ++i) {
    var line = chunk.lines[i]
    if (line == lineObj) { break }
    else { h += line.height }
  }
  for (var p = chunk.parent; p; chunk = p, p = chunk.parent) {
    for (var i$1 = 0; i$1 < p.children.length; ++i$1) {
      var cur = p.children[i$1]
      if (cur == chunk) { break }
      else { h += cur.height }
    }
  }
  return h
}

// Compute the character length of a line, taking into account
// collapsed ranges (see markText) that might hide parts, and join
// other lines onto it.
function lineLength(line) {
  if (line.height == 0) { return 0 }
  var len = line.text.length, merged, cur = line
  while (merged = collapsedSpanAtStart(cur)) {
    var found = merged.find(0, true)
    cur = found.from.line
    len += found.from.ch - found.to.ch
  }
  cur = line
  while (merged = collapsedSpanAtEnd(cur)) {
    var found$1 = merged.find(0, true)
    len -= cur.text.length - found$1.from.ch
    cur = found$1.to.line
    len += cur.text.length - found$1.to.ch
  }
  return len
}

// Find the longest line in the document.
function findMaxLine(cm) {
  var d = cm.display, doc = cm.doc
  d.maxLine = getLine(doc, doc.first)
  d.maxLineLength = lineLength(d.maxLine)
  d.maxLineChanged = true
  doc.iter(function (line) {
    var len = lineLength(line)
    if (len > d.maxLineLength) {
      d.maxLineLength = len
      d.maxLine = line
    }
  })
}

// BIDI HELPERS

function iterateBidiSections(order, from, to, f) {
  if (!order) { return f(from, to, "ltr", 0) }
  var found = false
  for (var i = 0; i < order.length; ++i) {
    var part = order[i]
    if (part.from < to && part.to > from || from == to && part.to == from) {
      f(Math.max(part.from, from), Math.min(part.to, to), part.level == 1 ? "rtl" : "ltr", i)
      found = true
    }
  }
  if (!found) { f(from, to, "ltr") }
}

var bidiOther = null
function getBidiPartAt(order, ch, sticky) {
  var found
  bidiOther = null
  for (var i = 0; i < order.length; ++i) {
    var cur = order[i]
    if (cur.from < ch && cur.to > ch) { return i }
    if (cur.to == ch) {
      if (cur.from != cur.to && sticky == "before") { found = i }
      else { bidiOther = i }
    }
    if (cur.from == ch) {
      if (cur.from != cur.to && sticky != "before") { found = i }
      else { bidiOther = i }
    }
  }
  return found != null ? found : bidiOther
}

// Bidirectional ordering algorithm
// See http://unicode.org/reports/tr9/tr9-13.html for the algorithm
// that this (partially) implements.

// One-char codes used for character types:
// L (L):   Left-to-Right
// R (R):   Right-to-Left
// r (AL):  Right-to-Left Arabic
// 1 (EN):  European Number
// + (ES):  European Number Separator
// % (ET):  European Number Terminator
// n (AN):  Arabic Number
// , (CS):  Common Number Separator
// m (NSM): Non-Spacing Mark
// b (BN):  Boundary Neutral
// s (B):   Paragraph Separator
// t (S):   Segment Separator
// w (WS):  Whitespace
// N (ON):  Other Neutrals

// Returns null if characters are ordered as they appear
// (left-to-right), or an array of sections ({from, to, level}
// objects) in the order in which they occur visually.
var bidiOrdering = (function() {
  // Character types for codepoints 0 to 0xff
  var lowTypes = "bbbbbbbbbtstwsbbbbbbbbbbbbbbssstwNN%%%NNNNNN,N,N1111111111NNNNNNNLLLLLLLLLLLLLLLLLLLLLLLLLLNNNNNNLLLLLLLLLLLLLLLLLLLLLLLLLLNNNNbbbbbbsbbbbbbbbbbbbbbbbbbbbbbbbbb,N%%%%NNNNLNNNNN%%11NLNNN1LNNNNNLLLLLLLLLLLLLLLLLLLLLLLNLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLN"
  // Character types for codepoints 0x600 to 0x6f9
  var arabicTypes = "nnnnnnNNr%%r,rNNmmmmmmmmmmmrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrmmmmmmmmmmmmmmmmmmmmmnnnnnnnnnn%nnrrrmrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrmmmmmmmnNmmmmmmrrmmNmmmmrr1111111111"
  function charType(code) {
    if (code <= 0xf7) { return lowTypes.charAt(code) }
    else if (0x590 <= code && code <= 0x5f4) { return "R" }
    else if (0x600 <= code && code <= 0x6f9) { return arabicTypes.charAt(code - 0x600) }
    else if (0x6ee <= code && code <= 0x8ac) { return "r" }
    else if (0x2000 <= code && code <= 0x200b) { return "w" }
    else if (code == 0x200c) { return "b" }
    else { return "L" }
  }

  var bidiRE = /[\u0590-\u05f4\u0600-\u06ff\u0700-\u08ac]/
  var isNeutral = /[stwN]/, isStrong = /[LRr]/, countsAsLeft = /[Lb1n]/, countsAsNum = /[1n]/

  function BidiSpan(level, from, to) {
    this.level = level
    this.from = from; this.to = to
  }

  return function(str, direction) {
    var outerType = direction == "ltr" ? "L" : "R"

    if (str.length == 0 || direction == "ltr" && !bidiRE.test(str)) { return false }
    var len = str.length, types = []
    for (var i = 0; i < len; ++i)
      { types.push(charType(str.charCodeAt(i))) }

    // W1. Examine each non-spacing mark (NSM) in the level run, and
    // change the type of the NSM to the type of the previous
    // character. If the NSM is at the start of the level run, it will
    // get the type of sor.
    for (var i$1 = 0, prev = outerType; i$1 < len; ++i$1) {
      var type = types[i$1]
      if (type == "m") { types[i$1] = prev }
      else { prev = type }
    }

    // W2. Search backwards from each instance of a European number
    // until the first strong type (R, L, AL, or sor) is found. If an
    // AL is found, change the type of the European number to Arabic
    // number.
    // W3. Change all ALs to R.
    for (var i$2 = 0, cur = outerType; i$2 < len; ++i$2) {
      var type$1 = types[i$2]
      if (type$1 == "1" && cur == "r") { types[i$2] = "n" }
      else if (isStrong.test(type$1)) { cur = type$1; if (type$1 == "r") { types[i$2] = "R" } }
    }

    // W4. A single European separator between two European numbers
    // changes to a European number. A single common separator between
    // two numbers of the same type changes to that type.
    for (var i$3 = 1, prev$1 = types[0]; i$3 < len - 1; ++i$3) {
      var type$2 = types[i$3]
      if (type$2 == "+" && prev$1 == "1" && types[i$3+1] == "1") { types[i$3] = "1" }
      else if (type$2 == "," && prev$1 == types[i$3+1] &&
               (prev$1 == "1" || prev$1 == "n")) { types[i$3] = prev$1 }
      prev$1 = type$2
    }

    // W5. A sequence of European terminators adjacent to European
    // numbers changes to all European numbers.
    // W6. Otherwise, separators and terminators change to Other
    // Neutral.
    for (var i$4 = 0; i$4 < len; ++i$4) {
      var type$3 = types[i$4]
      if (type$3 == ",") { types[i$4] = "N" }
      else if (type$3 == "%") {
        var end = (void 0)
        for (end = i$4 + 1; end < len && types[end] == "%"; ++end) {}
        var replace = (i$4 && types[i$4-1] == "!") || (end < len && types[end] == "1") ? "1" : "N"
        for (var j = i$4; j < end; ++j) { types[j] = replace }
        i$4 = end - 1
      }
    }

    // W7. Search backwards from each instance of a European number
    // until the first strong type (R, L, or sor) is found. If an L is
    // found, then change the type of the European number to L.
    for (var i$5 = 0, cur$1 = outerType; i$5 < len; ++i$5) {
      var type$4 = types[i$5]
      if (cur$1 == "L" && type$4 == "1") { types[i$5] = "L" }
      else if (isStrong.test(type$4)) { cur$1 = type$4 }
    }

    // N1. A sequence of neutrals takes the direction of the
    // surrounding strong text if the text on both sides has the same
    // direction. European and Arabic numbers act as if they were R in
    // terms of their influence on neutrals. Start-of-level-run (sor)
    // and end-of-level-run (eor) are used at level run boundaries.
    // N2. Any remaining neutrals take the embedding direction.
    for (var i$6 = 0; i$6 < len; ++i$6) {
      if (isNeutral.test(types[i$6])) {
        var end$1 = (void 0)
        for (end$1 = i$6 + 1; end$1 < len && isNeutral.test(types[end$1]); ++end$1) {}
        var before = (i$6 ? types[i$6-1] : outerType) == "L"
        var after = (end$1 < len ? types[end$1] : outerType) == "L"
        var replace$1 = before == after ? (before ? "L" : "R") : outerType
        for (var j$1 = i$6; j$1 < end$1; ++j$1) { types[j$1] = replace$1 }
        i$6 = end$1 - 1
      }
    }

    // Here we depart from the documented algorithm, in order to avoid
    // building up an actual levels array. Since there are only three
    // levels (0, 1, 2) in an implementation that doesn't take
    // explicit embedding into account, we can build up the order on
    // the fly, without following the level-based algorithm.
    var order = [], m
    for (var i$7 = 0; i$7 < len;) {
      if (countsAsLeft.test(types[i$7])) {
        var start = i$7
        for (++i$7; i$7 < len && countsAsLeft.test(types[i$7]); ++i$7) {}
        order.push(new BidiSpan(0, start, i$7))
      } else {
        var pos = i$7, at = order.length
        for (++i$7; i$7 < len && types[i$7] != "L"; ++i$7) {}
        for (var j$2 = pos; j$2 < i$7;) {
          if (countsAsNum.test(types[j$2])) {
            if (pos < j$2) { order.splice(at, 0, new BidiSpan(1, pos, j$2)) }
            var nstart = j$2
            for (++j$2; j$2 < i$7 && countsAsNum.test(types[j$2]); ++j$2) {}
            order.splice(at, 0, new BidiSpan(2, nstart, j$2))
            pos = j$2
          } else { ++j$2 }
        }
        if (pos < i$7) { order.splice(at, 0, new BidiSpan(1, pos, i$7)) }
      }
    }
    if (direction == "ltr") {
      if (order[0].level == 1 && (m = str.match(/^\s+/))) {
        order[0].from = m[0].length
        order.unshift(new BidiSpan(0, 0, m[0].length))
      }
      if (lst(order).level == 1 && (m = str.match(/\s+$/))) {
        lst(order).to -= m[0].length
        order.push(new BidiSpan(0, len - m[0].length, len))
      }
    }

    return direction == "rtl" ? order.reverse() : order
  }
})()

// Get the bidi ordering for the given line (and cache it). Returns
// false for lines that are fully left-to-right, and an array of
// BidiSpan objects otherwise.
function getOrder(line, direction) {
  var order = line.order
  if (order == null) { order = line.order = bidiOrdering(line.text, direction) }
  return order
}

// EVENT HANDLING

// Lightweight event framework. on/off also work on DOM nodes,
// registering native DOM handlers.

var noHandlers = []

var on = function(emitter, type, f) {
  if (emitter.addEventListener) {
    emitter.addEventListener(type, f, false)
  } else if (emitter.attachEvent) {
    emitter.attachEvent("on" + type, f)
  } else {
    var map = emitter._handlers || (emitter._handlers = {})
    map[type] = (map[type] || noHandlers).concat(f)
  }
}

function getHandlers(emitter, type) {
  return emitter._handlers && emitter._handlers[type] || noHandlers
}

function off(emitter, type, f) {
  if (emitter.removeEventListener) {
    emitter.removeEventListener(type, f, false)
  } else if (emitter.detachEvent) {
    emitter.detachEvent("on" + type, f)
  } else {
    var map = emitter._handlers, arr = map && map[type]
    if (arr) {
      var index = indexOf(arr, f)
      if (index > -1)
        { map[type] = arr.slice(0, index).concat(arr.slice(index + 1)) }
    }
  }
}

function signal(emitter, type /*, values...*/) {
  var handlers = getHandlers(emitter, type)
  if (!handlers.length) { return }
  var args = Array.prototype.slice.call(arguments, 2)
  for (var i = 0; i < handlers.length; ++i) { handlers[i].apply(null, args) }
}

// The DOM events that CodeMirror handles can be overridden by
// registering a (non-DOM) handler on the editor for the event name,
// and preventDefault-ing the event in that handler.
function signalDOMEvent(cm, e, override) {
  if (typeof e == "string")
    { e = {type: e, preventDefault: function() { this.defaultPrevented = true }} }
  signal(cm, override || e.type, cm, e)
  return e_defaultPrevented(e) || e.codemirrorIgnore
}

function signalCursorActivity(cm) {
  var arr = cm._handlers && cm._handlers.cursorActivity
  if (!arr) { return }
  var set = cm.curOp.cursorActivityHandlers || (cm.curOp.cursorActivityHandlers = [])
  for (var i = 0; i < arr.length; ++i) { if (indexOf(set, arr[i]) == -1)
    { set.push(arr[i]) } }
}

function hasHandler(emitter, type) {
  return getHandlers(emitter, type).length > 0
}

// Add on and off methods to a constructor's prototype, to make
// registering events on such objects more convenient.
function eventMixin(ctor) {
  ctor.prototype.on = function(type, f) {on(this, type, f)}
  ctor.prototype.off = function(type, f) {off(this, type, f)}
}

// Due to the fact that we still support jurassic IE versions, some
// compatibility wrappers are needed.

function e_preventDefault(e) {
  if (e.preventDefault) { e.preventDefault() }
  else { e.returnValue = false }
}
function e_stopPropagation(e) {
  if (e.stopPropagation) { e.stopPropagation() }
  else { e.cancelBubble = true }
}
function e_defaultPrevented(e) {
  return e.defaultPrevented != null ? e.defaultPrevented : e.returnValue == false
}
function e_stop(e) {e_preventDefault(e); e_stopPropagation(e)}

function e_target(e) {return e.target || e.srcElement}
function e_button(e) {
  var b = e.which
  if (b == null) {
    if (e.button & 1) { b = 1 }
    else if (e.button & 2) { b = 3 }
    else if (e.button & 4) { b = 2 }
  }
  if (mac && e.ctrlKey && b == 1) { b = 3 }
  return b
}

// Detect drag-and-drop
var dragAndDrop = function() {
  // There is *some* kind of drag-and-drop support in IE6-8, but I
  // couldn't get it to work yet.
  if (ie && ie_version < 9) { return false }
  var div = elt('div')
  return "draggable" in div || "dragDrop" in div
}()

var zwspSupported
function zeroWidthElement(measure) {
  if (zwspSupported == null) {
    var test = elt("span", "\u200b")
    removeChildrenAndAdd(measure, elt("span", [test, document.createTextNode("x")]))
    if (measure.firstChild.offsetHeight != 0)
      { zwspSupported = test.offsetWidth <= 1 && test.offsetHeight > 2 && !(ie && ie_version < 8) }
  }
  var node = zwspSupported ? elt("span", "\u200b") :
    elt("span", "\u00a0", null, "display: inline-block; width: 1px; margin-right: -1px")
  node.setAttribute("cm-text", "")
  return node
}

// Feature-detect IE's crummy client rect reporting for bidi text
var badBidiRects
function hasBadBidiRects(measure) {
  if (badBidiRects != null) { return badBidiRects }
  var txt = removeChildrenAndAdd(measure, document.createTextNode("A\u062eA"))
  var r0 = range(txt, 0, 1).getBoundingClientRect()
  var r1 = range(txt, 1, 2).getBoundingClientRect()
  removeChildren(measure)
  if (!r0 || r0.left == r0.right) { return false } // Safari returns null in some cases (#2780)
  return badBidiRects = (r1.right - r0.right < 3)
}

// See if "".split is the broken IE version, if so, provide an
// alternative way to split lines.
var splitLinesAuto = "\n\nb".split(/\n/).length != 3 ? function (string) {
  var pos = 0, result = [], l = string.length
  while (pos <= l) {
    var nl = string.indexOf("\n", pos)
    if (nl == -1) { nl = string.length }
    var line = string.slice(pos, string.charAt(nl - 1) == "\r" ? nl - 1 : nl)
    var rt = line.indexOf("\r")
    if (rt != -1) {
      result.push(line.slice(0, rt))
      pos += rt + 1
    } else {
      result.push(line)
      pos = nl + 1
    }
  }
  return result
} : function (string) { return string.split(/\r\n?|\n/); }

var hasSelection = window.getSelection ? function (te) {
  try { return te.selectionStart != te.selectionEnd }
  catch(e) { return false }
} : function (te) {
  var range
  try {range = te.ownerDocument.selection.createRange()}
  catch(e) {}
  if (!range || range.parentElement() != te) { return false }
  return range.compareEndPoints("StartToEnd", range) != 0
}

var hasCopyEvent = (function () {
  var e = elt("div")
  if ("oncopy" in e) { return true }
  e.setAttribute("oncopy", "return;")
  return typeof e.oncopy == "function"
})()

var badZoomedRects = null
function hasBadZoomedRects(measure) {
  if (badZoomedRects != null) { return badZoomedRects }
  var node = removeChildrenAndAdd(measure, elt("span", "x"))
  var normal = node.getBoundingClientRect()
  var fromRange = range(node, 0, 1).getBoundingClientRect()
  return badZoomedRects = Math.abs(normal.left - fromRange.left) > 1
}

var modes = {};
var mimeModes = {};
// Extra arguments are stored as the mode's dependencies, which is
// used by (legacy) mechanisms like loadmode.js to automatically
// load a mode. (Preferred mechanism is the require/define calls.)
function defineMode(name, mode) {
  if (arguments.length > 2)
    { mode.dependencies = Array.prototype.slice.call(arguments, 2) }
  modes[name] = mode
}

function defineMIME(mime, spec) {
  mimeModes[mime] = spec
}

// Given a MIME type, a {name, ...options} config object, or a name
// string, return a mode config object.
function resolveMode(spec) {
  if (typeof spec == "string" && mimeModes.hasOwnProperty(spec)) {
    spec = mimeModes[spec]
  } else if (spec && typeof spec.name == "string" && mimeModes.hasOwnProperty(spec.name)) {
    var found = mimeModes[spec.name]
    if (typeof found == "string") { found = {name: found} }
    spec = createObj(found, spec)
    spec.name = found.name
  } else if (typeof spec == "string" && /^[\w\-]+\/[\w\-]+\+xml$/.test(spec)) {
    return resolveMode("application/xml")
  } else if (typeof spec == "string" && /^[\w\-]+\/[\w\-]+\+json$/.test(spec)) {
    return resolveMode("application/json")
  }
  if (typeof spec == "string") { return {name: spec} }
  else { return spec || {name: "null"} }
}

// Given a mode spec (anything that resolveMode accepts), find and
// initialize an actual mode object.
function getMode(options, spec) {
  spec = resolveMode(spec)
  var mfactory = modes[spec.name]
  if (!mfactory) { return getMode(options, "text/plain") }
  var modeObj = mfactory(options, spec)
  if (modeExtensions.hasOwnProperty(spec.name)) {
    var exts = modeExtensions[spec.name]
    for (var prop in exts) {
      if (!exts.hasOwnProperty(prop)) { continue }
      if (modeObj.hasOwnProperty(prop)) { modeObj["_" + prop] = modeObj[prop] }
      modeObj[prop] = exts[prop]
    }
  }
  modeObj.name = spec.name
  if (spec.helperType) { modeObj.helperType = spec.helperType }
  if (spec.modeProps) { for (var prop$1 in spec.modeProps)
    { modeObj[prop$1] = spec.modeProps[prop$1] } }

  return modeObj
}

// This can be used to attach properties to mode objects from
// outside the actual mode definition.
var modeExtensions = {}
function extendMode(mode, properties) {
  var exts = modeExtensions.hasOwnProperty(mode) ? modeExtensions[mode] : (modeExtensions[mode] = {})
  copyObj(properties, exts)
}

function copyState(mode, state) {
  if (state === true) { return state }
  if (mode.copyState) { return mode.copyState(state) }
  var nstate = {}
  for (var n in state) {
    var val = state[n]
    if (val instanceof Array) { val = val.concat([]) }
    nstate[n] = val
  }
  return nstate
}

// Given a mode and a state (for that mode), find the inner mode and
// state at the position that the state refers to.
function innerMode(mode, state) {
  var info
  while (mode.innerMode) {
    info = mode.innerMode(state)
    if (!info || info.mode == mode) { break }
    state = info.state
    mode = info.mode
  }
  return info || {mode: mode, state: state}
}

function startState(mode, a1, a2) {
  return mode.startState ? mode.startState(a1, a2) : true
}

// STRING STREAM

// Fed to the mode parsers, provides helper functions to make
// parsers more succinct.

var StringStream = function(string, tabSize, lineOracle) {
  this.pos = this.start = 0
  this.string = string
  this.tabSize = tabSize || 8
  this.lastColumnPos = this.lastColumnValue = 0
  this.lineStart = 0
  this.lineOracle = lineOracle
};

StringStream.prototype.eol = function () {return this.pos >= this.string.length};
StringStream.prototype.sol = function () {return this.pos == this.lineStart};
StringStream.prototype.peek = function () {return this.string.charAt(this.pos) || undefined};
StringStream.prototype.next = function () {
  if (this.pos < this.string.length)
    { return this.string.charAt(this.pos++) }
};
StringStream.prototype.eat = function (match) {
  var ch = this.string.charAt(this.pos)
  var ok
  if (typeof match == "string") { ok = ch == match }
  else { ok = ch && (match.test ? match.test(ch) : match(ch)) }
  if (ok) {++this.pos; return ch}
};
StringStream.prototype.eatWhile = function (match) {
  var start = this.pos
  while (this.eat(match)){}
  return this.pos > start
};
StringStream.prototype.eatSpace = function () {
    var this$1 = this;

  var start = this.pos
  while (/[\s\u00a0]/.test(this.string.charAt(this.pos))) { ++this$1.pos }
  return this.pos > start
};
StringStream.prototype.skipToEnd = function () {this.pos = this.string.length};
StringStream.prototype.skipTo = function (ch) {
  var found = this.string.indexOf(ch, this.pos)
  if (found > -1) {this.pos = found; return true}
};
StringStream.prototype.backUp = function (n) {this.pos -= n};
StringStream.prototype.column = function () {
  if (this.lastColumnPos < this.start) {
    this.lastColumnValue = countColumn(this.string, this.start, this.tabSize, this.lastColumnPos, this.lastColumnValue)
    this.lastColumnPos = this.start
  }
  return this.lastColumnValue - (this.lineStart ? countColumn(this.string, this.lineStart, this.tabSize) : 0)
};
StringStream.prototype.indentation = function () {
  return countColumn(this.string, null, this.tabSize) -
    (this.lineStart ? countColumn(this.string, this.lineStart, this.tabSize) : 0)
};
StringStream.prototype.match = function (pattern, consume, caseInsensitive) {
  if (typeof pattern == "string") {
    var cased = function (str) { return caseInsensitive ? str.toLowerCase() : str; }
    var substr = this.string.substr(this.pos, pattern.length)
    if (cased(substr) == cased(pattern)) {
      if (consume !== false) { this.pos += pattern.length }
      return true
    }
  } else {
    var match = this.string.slice(this.pos).match(pattern)
    if (match && match.index > 0) { return null }
    if (match && consume !== false) { this.pos += match[0].length }
    return match
  }
};
StringStream.prototype.current = function (){return this.string.slice(this.start, this.pos)};
StringStream.prototype.hideFirstChars = function (n, inner) {
  this.lineStart += n
  try { return inner() }
  finally { this.lineStart -= n }
};
StringStream.prototype.lookAhead = function (n) {
  var oracle = this.lineOracle
  return oracle && oracle.lookAhead(n)
};
StringStream.prototype.baseToken = function () {
  var oracle = this.lineOracle
  return oracle && oracle.baseToken(this.pos)
};

var SavedContext = function(state, lookAhead) {
  this.state = state
  this.lookAhead = lookAhead
};

var Context = function(doc, state, line, lookAhead) {
  this.state = state
  this.doc = doc
  this.line = line
  this.maxLookAhead = lookAhead || 0
  this.baseTokens = null
  this.baseTokenPos = 1
};

Context.prototype.lookAhead = function (n) {
  var line = this.doc.getLine(this.line + n)
  if (line != null && n > this.maxLookAhead) { this.maxLookAhead = n }
  return line
};

Context.prototype.baseToken = function (n) {
    var this$1 = this;

  if (!this.baseTokens) { return null }
  while (this.baseTokens[this.baseTokenPos] <= n)
    { this$1.baseTokenPos += 2 }
  var type = this.baseTokens[this.baseTokenPos + 1]
  return {type: type && type.replace(/( |^)overlay .*/, ""),
          size: this.baseTokens[this.baseTokenPos] - n}
};

Context.prototype.nextLine = function () {
  this.line++
  if (this.maxLookAhead > 0) { this.maxLookAhead-- }
};

Context.fromSaved = function (doc, saved, line) {
  if (saved instanceof SavedContext)
    { return new Context(doc, copyState(doc.mode, saved.state), line, saved.lookAhead) }
  else
    { return new Context(doc, copyState(doc.mode, saved), line) }
};

Context.prototype.save = function (copy) {
  var state = copy !== false ? copyState(this.doc.mode, this.state) : this.state
  return this.maxLookAhead > 0 ? new SavedContext(state, this.maxLookAhead) : state
};


// Compute a style array (an array starting with a mode generation
// -- for invalidation -- followed by pairs of end positions and
// style strings), which is used to highlight the tokens on the
// line.
function highlightLine(cm, line, context, forceToEnd) {
  // A styles array always starts with a number identifying the
  // mode/overlays that it is based on (for easy invalidation).
  var st = [cm.state.modeGen], lineClasses = {}
  // Compute the base array of styles
  runMode(cm, line.text, cm.doc.mode, context, function (end, style) { return st.push(end, style); },
          lineClasses, forceToEnd)
  var state = context.state

  // Run overlays, adjust style array.
  var loop = function ( o ) {
    context.baseTokens = st
    var overlay = cm.state.overlays[o], i = 1, at = 0
    context.state = true
    runMode(cm, line.text, overlay.mode, context, function (end, style) {
      var start = i
      // Ensure there's a token end at the current position, and that i points at it
      while (at < end) {
        var i_end = st[i]
        if (i_end > end)
          { st.splice(i, 1, end, st[i+1], i_end) }
        i += 2
        at = Math.min(end, i_end)
      }
      if (!style) { return }
      if (overlay.opaque) {
        st.splice(start, i - start, end, "overlay " + style)
        i = start + 2
      } else {
        for (; start < i; start += 2) {
          var cur = st[start+1]
          st[start+1] = (cur ? cur + " " : "") + "overlay " + style
        }
      }
    }, lineClasses)
    context.state = state
    context.baseTokens = null
    context.baseTokenPos = 1
  };

  for (var o = 0; o < cm.state.overlays.length; ++o) loop( o );

  return {styles: st, classes: lineClasses.bgClass || lineClasses.textClass ? lineClasses : null}
}

function getLineStyles(cm, line, updateFrontier) {
  if (!line.styles || line.styles[0] != cm.state.modeGen) {
    var context = getContextBefore(cm, lineNo(line))
    var resetState = line.text.length > cm.options.maxHighlightLength && copyState(cm.doc.mode, context.state)
    var result = highlightLine(cm, line, context)
    if (resetState) { context.state = resetState }
    line.stateAfter = context.save(!resetState)
    line.styles = result.styles
    if (result.classes) { line.styleClasses = result.classes }
    else if (line.styleClasses) { line.styleClasses = null }
    if (updateFrontier === cm.doc.highlightFrontier)
      { cm.doc.modeFrontier = Math.max(cm.doc.modeFrontier, ++cm.doc.highlightFrontier) }
  }
  return line.styles
}

function getContextBefore(cm, n, precise) {
  var doc = cm.doc, display = cm.display
  if (!doc.mode.startState) { return new Context(doc, true, n) }
  var start = findStartLine(cm, n, precise)
  var saved = start > doc.first && getLine(doc, start - 1).stateAfter
  var context = saved ? Context.fromSaved(doc, saved, start) : new Context(doc, startState(doc.mode), start)

  doc.iter(start, n, function (line) {
    processLine(cm, line.text, context)
    var pos = context.line
    line.stateAfter = pos == n - 1 || pos % 5 == 0 || pos >= display.viewFrom && pos < display.viewTo ? context.save() : null
    context.nextLine()
  })
  if (precise) { doc.modeFrontier = context.line }
  return context
}

// Lightweight form of highlight -- proceed over this line and
// update state, but don't save a style array. Used for lines that
// aren't currently visible.
function processLine(cm, text, context, startAt) {
  var mode = cm.doc.mode
  var stream = new StringStream(text, cm.options.tabSize, context)
  stream.start = stream.pos = startAt || 0
  if (text == "") { callBlankLine(mode, context.state) }
  while (!stream.eol()) {
    readToken(mode, stream, context.state)
    stream.start = stream.pos
  }
}

function callBlankLine(mode, state) {
  if (mode.blankLine) { return mode.blankLine(state) }
  if (!mode.innerMode) { return }
  var inner = innerMode(mode, state)
  if (inner.mode.blankLine) { return inner.mode.blankLine(inner.state) }
}

function readToken(mode, stream, state, inner) {
  for (var i = 0; i < 10; i++) {
    if (inner) { inner[0] = innerMode(mode, state).mode }
    var style = mode.token(stream, state)
    if (stream.pos > stream.start) { return style }
  }
  throw new Error("Mode " + mode.name + " failed to advance stream.")
}

var Token = function(stream, type, state) {
  this.start = stream.start; this.end = stream.pos
  this.string = stream.current()
  this.type = type || null
  this.state = state
};

// Utility for getTokenAt and getLineTokens
function takeToken(cm, pos, precise, asArray) {
  var doc = cm.doc, mode = doc.mode, style
  pos = clipPos(doc, pos)
  var line = getLine(doc, pos.line), context = getContextBefore(cm, pos.line, precise)
  var stream = new StringStream(line.text, cm.options.tabSize, context), tokens
  if (asArray) { tokens = [] }
  while ((asArray || stream.pos < pos.ch) && !stream.eol()) {
    stream.start = stream.pos
    style = readToken(mode, stream, context.state)
    if (asArray) { tokens.push(new Token(stream, style, copyState(doc.mode, context.state))) }
  }
  return asArray ? tokens : new Token(stream, style, context.state)
}

function extractLineClasses(type, output) {
  if (type) { for (;;) {
    var lineClass = type.match(/(?:^|\s+)line-(background-)?(\S+)/)
    if (!lineClass) { break }
    type = type.slice(0, lineClass.index) + type.slice(lineClass.index + lineClass[0].length)
    var prop = lineClass[1] ? "bgClass" : "textClass"
    if (output[prop] == null)
      { output[prop] = lineClass[2] }
    else if (!(new RegExp("(?:^|\s)" + lineClass[2] + "(?:$|\s)")).test(output[prop]))
      { output[prop] += " " + lineClass[2] }
  } }
  return type
}

// Run the given mode's parser over a line, calling f for each token.
function runMode(cm, text, mode, context, f, lineClasses, forceToEnd) {
  var flattenSpans = mode.flattenSpans
  if (flattenSpans == null) { flattenSpans = cm.options.flattenSpans }
  var curStart = 0, curStyle = null
  var stream = new StringStream(text, cm.options.tabSize, context), style
  var inner = cm.options.addModeClass && [null]
  if (text == "") { extractLineClasses(callBlankLine(mode, context.state), lineClasses) }
  while (!stream.eol()) {
    if (stream.pos > cm.options.maxHighlightLength) {
      flattenSpans = false
      if (forceToEnd) { processLine(cm, text, context, stream.pos) }
      stream.pos = text.length
      style = null
    } else {
      style = extractLineClasses(readToken(mode, stream, context.state, inner), lineClasses)
    }
    if (inner) {
      var mName = inner[0].name
      if (mName) { style = "m-" + (style ? mName + " " + style : mName) }
    }
    if (!flattenSpans || curStyle != style) {
      while (curStart < stream.start) {
        curStart = Math.min(stream.start, curStart + 5000)
        f(curStart, curStyle)
      }
      curStyle = style
    }
    stream.start = stream.pos
  }
  while (curStart < stream.pos) {
    // Webkit seems to refuse to render text nodes longer than 57444
    // characters, and returns inaccurate measurements in nodes
    // starting around 5000 chars.
    var pos = Math.min(stream.pos, curStart + 5000)
    f(pos, curStyle)
    curStart = pos
  }
}

// Finds the line to start with when starting a parse. Tries to
// find a line with a stateAfter, so that it can start with a
// valid state. If that fails, it returns the line with the
// smallest indentation, which tends to need the least context to
// parse correctly.
function findStartLine(cm, n, precise) {
  var minindent, minline, doc = cm.doc
  var lim = precise ? -1 : n - (cm.doc.mode.innerMode ? 1000 : 100)
  for (var search = n; search > lim; --search) {
    if (search <= doc.first) { return doc.first }
    var line = getLine(doc, search - 1), after = line.stateAfter
    if (after && (!precise || search + (after instanceof SavedContext ? after.lookAhead : 0) <= doc.modeFrontier))
      { return search }
    var indented = countColumn(line.text, null, cm.options.tabSize)
    if (minline == null || minindent > indented) {
      minline = search - 1
      minindent = indented
    }
  }
  return minline
}

function retreatFrontier(doc, n) {
  doc.modeFrontier = Math.min(doc.modeFrontier, n)
  if (doc.highlightFrontier < n - 10) { return }
  var start = doc.first
  for (var line = n - 1; line > start; line--) {
    var saved = getLine(doc, line).stateAfter
    // change is on 3
    // state on line 1 looked ahead 2 -- so saw 3
    // test 1 + 2 < 3 should cover this
    if (saved && (!(saved instanceof SavedContext) || line + saved.lookAhead < n)) {
      start = line + 1
      break
    }
  }
  doc.highlightFrontier = Math.min(doc.highlightFrontier, start)
}

// LINE DATA STRUCTURE

// Line objects. These hold state related to a line, including
// highlighting info (the styles array).
var Line = function(text, markedSpans, estimateHeight) {
  this.text = text
  attachMarkedSpans(this, markedSpans)
  this.height = estimateHeight ? estimateHeight(this) : 1
};

Line.prototype.lineNo = function () { return lineNo(this) };
eventMixin(Line)

// Change the content (text, markers) of a line. Automatically
// invalidates cached information and tries to re-estimate the
// line's height.
function updateLine(line, text, markedSpans, estimateHeight) {
  line.text = text
  if (line.stateAfter) { line.stateAfter = null }
  if (line.styles) { line.styles = null }
  if (line.order != null) { line.order = null }
  detachMarkedSpans(line)
  attachMarkedSpans(line, markedSpans)
  var estHeight = estimateHeight ? estimateHeight(line) : 1
  if (estHeight != line.height) { updateLineHeight(line, estHeight) }
}

// Detach a line from the document tree and its markers.
function cleanUpLine(line) {
  line.parent = null
  detachMarkedSpans(line)
}

// Convert a style as returned by a mode (either null, or a string
// containing one or more styles) to a CSS style. This is cached,
// and also looks for line-wide styles.
var styleToClassCache = {};
var styleToClassCacheWithMode = {};
function interpretTokenStyle(style, options) {
  if (!style || /^\s*$/.test(style)) { return null }
  var cache = options.addModeClass ? styleToClassCacheWithMode : styleToClassCache
  return cache[style] ||
    (cache[style] = style.replace(/\S+/g, "cm-$&"))
}

// Render the DOM representation of the text of a line. Also builds
// up a 'line map', which points at the DOM nodes that represent
// specific stretches of text, and is used by the measuring code.
// The returned object contains the DOM node, this map, and
// information about line-wide styles that were set by the mode.
function buildLineContent(cm, lineView) {
  // The padding-right forces the element to have a 'border', which
  // is needed on Webkit to be able to get line-level bounding
  // rectangles for it (in measureChar).
  var content = eltP("span", null, null, webkit ? "padding-right: .1px" : null)
  var builder = {pre: eltP("pre", [content], "CodeMirror-line"), content: content,
                 col: 0, pos: 0, cm: cm,
                 trailingSpace: false,
                 splitSpaces: cm.getOption("lineWrapping")}
  lineView.measure = {}

  // Iterate over the logical lines that make up this visual line.
  for (var i = 0; i <= (lineView.rest ? lineView.rest.length : 0); i++) {
    var line = i ? lineView.rest[i - 1] : lineView.line, order = (void 0)
    builder.pos = 0
    builder.addToken = buildToken
    // Optionally wire in some hacks into the token-rendering
    // algorithm, to deal with browser quirks.
    if (hasBadBidiRects(cm.display.measure) && (order = getOrder(line, cm.doc.direction)))
      { builder.addToken = buildTokenBadBidi(builder.addToken, order) }
    builder.map = []
    var allowFrontierUpdate = lineView != cm.display.externalMeasured && lineNo(line)
    insertLineContent(line, builder, getLineStyles(cm, line, allowFrontierUpdate))
    if (line.styleClasses) {
      if (line.styleClasses.bgClass)
        { builder.bgClass = joinClasses(line.styleClasses.bgClass, builder.bgClass || "") }
      if (line.styleClasses.textClass)
        { builder.textClass = joinClasses(line.styleClasses.textClass, builder.textClass || "") }
    }

    // Ensure at least a single node is present, for measuring.
    if (builder.map.length == 0)
      { builder.map.push(0, 0, builder.content.appendChild(zeroWidthElement(cm.display.measure))) }

    // Store the map and a cache object for the current logical line
    if (i == 0) {
      lineView.measure.map = builder.map
      lineView.measure.cache = {}
    } else {
      ;(lineView.measure.maps || (lineView.measure.maps = [])).push(builder.map)
      ;(lineView.measure.caches || (lineView.measure.caches = [])).push({})
    }
  }

  // See issue #2901
  if (webkit) {
    var last = builder.content.lastChild
    if (/\bcm-tab\b/.test(last.className) || (last.querySelector && last.querySelector(".cm-tab")))
      { builder.content.className = "cm-tab-wrap-hack" }
  }

  signal(cm, "renderLine", cm, lineView.line, builder.pre)
  if (builder.pre.className)
    { builder.textClass = joinClasses(builder.pre.className, builder.textClass || "") }

  return builder
}

function defaultSpecialCharPlaceholder(ch) {
  var token = elt("span", "\u2022", "cm-invalidchar")
  token.title = "\\u" + ch.charCodeAt(0).toString(16)
  token.setAttribute("aria-label", token.title)
  return token
}

// Build up the DOM representation for a single token, and add it to
// the line map. Takes care to render special characters separately.
function buildToken(builder, text, style, startStyle, endStyle, title, css) {
  if (!text) { return }
  var displayText = builder.splitSpaces ? splitSpaces(text, builder.trailingSpace) : text
  var special = builder.cm.state.specialChars, mustWrap = false
  var content
  if (!special.test(text)) {
    builder.col += text.length
    content = document.createTextNode(displayText)
    builder.map.push(builder.pos, builder.pos + text.length, content)
    if (ie && ie_version < 9) { mustWrap = true }
    builder.pos += text.length
  } else {
    content = document.createDocumentFragment()
    var pos = 0
    while (true) {
      special.lastIndex = pos
      var m = special.exec(text)
      var skipped = m ? m.index - pos : text.length - pos
      if (skipped) {
        var txt = document.createTextNode(displayText.slice(pos, pos + skipped))
        if (ie && ie_version < 9) { content.appendChild(elt("span", [txt])) }
        else { content.appendChild(txt) }
        builder.map.push(builder.pos, builder.pos + skipped, txt)
        builder.col += skipped
        builder.pos += skipped
      }
      if (!m) { break }
      pos += skipped + 1
      var txt$1 = (void 0)
      if (m[0] == "\t") {
        var tabSize = builder.cm.options.tabSize, tabWidth = tabSize - builder.col % tabSize
        txt$1 = content.appendChild(elt("span", spaceStr(tabWidth), "cm-tab"))
        txt$1.setAttribute("role", "presentation")
        txt$1.setAttribute("cm-text", "\t")
        builder.col += tabWidth
      } else if (m[0] == "\r" || m[0] == "\n") {
        txt$1 = content.appendChild(elt("span", m[0] == "\r" ? "\u240d" : "\u2424", "cm-invalidchar"))
        txt$1.setAttribute("cm-text", m[0])
        builder.col += 1
      } else {
        txt$1 = builder.cm.options.specialCharPlaceholder(m[0])
        txt$1.setAttribute("cm-text", m[0])
        if (ie && ie_version < 9) { content.appendChild(elt("span", [txt$1])) }
        else { content.appendChild(txt$1) }
        builder.col += 1
      }
      builder.map.push(builder.pos, builder.pos + 1, txt$1)
      builder.pos++
    }
  }
  builder.trailingSpace = displayText.charCodeAt(text.length - 1) == 32
  if (style || startStyle || endStyle || mustWrap || css) {
    var fullStyle = style || ""
    if (startStyle) { fullStyle += startStyle }
    if (endStyle) { fullStyle += endStyle }
    var token = elt("span", [content], fullStyle, css)
    if (title) { token.title = title }
    return builder.content.appendChild(token)
  }
  builder.content.appendChild(content)
}

// Change some spaces to NBSP to prevent the browser from collapsing
// trailing spaces at the end of a line when rendering text (issue #1362).
function splitSpaces(text, trailingBefore) {
  if (text.length > 1 && !/  /.test(text)) { return text }
  var spaceBefore = trailingBefore, result = ""
  for (var i = 0; i < text.length; i++) {
    var ch = text.charAt(i)
    if (ch == " " && spaceBefore && (i == text.length - 1 || text.charCodeAt(i + 1) == 32))
      { ch = "\u00a0" }
    result += ch
    spaceBefore = ch == " "
  }
  return result
}

// Work around nonsense dimensions being reported for stretches of
// right-to-left text.
function buildTokenBadBidi(inner, order) {
  return function (builder, text, style, startStyle, endStyle, title, css) {
    style = style ? style + " cm-force-border" : "cm-force-border"
    var start = builder.pos, end = start + text.length
    for (;;) {
      // Find the part that overlaps with the start of this text
      var part = (void 0)
      for (var i = 0; i < order.length; i++) {
        part = order[i]
        if (part.to > start && part.from <= start) { break }
      }
      if (part.to >= end) { return inner(builder, text, style, startStyle, endStyle, title, css) }
      inner(builder, text.slice(0, part.to - start), style, startStyle, null, title, css)
      startStyle = null
      text = text.slice(part.to - start)
      start = part.to
    }
  }
}

function buildCollapsedSpan(builder, size, marker, ignoreWidget) {
  var widget = !ignoreWidget && marker.widgetNode
  if (widget) { builder.map.push(builder.pos, builder.pos + size, widget) }
  if (!ignoreWidget && builder.cm.display.input.needsContentAttribute) {
    if (!widget)
      { widget = builder.content.appendChild(document.createElement("span")) }
    widget.setAttribute("cm-marker", marker.id)
  }
  if (widget) {
    builder.cm.display.input.setUneditable(widget)
    builder.content.appendChild(widget)
  }
  builder.pos += size
  builder.trailingSpace = false
}

// Outputs a number of spans to make up a line, taking highlighting
// and marked text into account.
function insertLineContent(line, builder, styles) {
  var spans = line.markedSpans, allText = line.text, at = 0
  if (!spans) {
    for (var i$1 = 1; i$1 < styles.length; i$1+=2)
      { builder.addToken(builder, allText.slice(at, at = styles[i$1]), interpretTokenStyle(styles[i$1+1], builder.cm.options)) }
    return
  }

  var len = allText.length, pos = 0, i = 1, text = "", style, css
  var nextChange = 0, spanStyle, spanEndStyle, spanStartStyle, title, collapsed
  for (;;) {
    if (nextChange == pos) { // Update current marker set
      spanStyle = spanEndStyle = spanStartStyle = title = css = ""
      collapsed = null; nextChange = Infinity
      var foundBookmarks = [], endStyles = (void 0)
      for (var j = 0; j < spans.length; ++j) {
        var sp = spans[j], m = sp.marker
        if (m.type == "bookmark" && sp.from == pos && m.widgetNode) {
          foundBookmarks.push(m)
        } else if (sp.from <= pos && (sp.to == null || sp.to > pos || m.collapsed && sp.to == pos && sp.from == pos)) {
          if (sp.to != null && sp.to != pos && nextChange > sp.to) {
            nextChange = sp.to
            spanEndStyle = ""
          }
          if (m.className) { spanStyle += " " + m.className }
          if (m.css) { css = (css ? css + ";" : "") + m.css }
          if (m.startStyle && sp.from == pos) { spanStartStyle += " " + m.startStyle }
          if (m.endStyle && sp.to == nextChange) { (endStyles || (endStyles = [])).push(m.endStyle, sp.to) }
          if (m.title && !title) { title = m.title }
          if (m.collapsed && (!collapsed || compareCollapsedMarkers(collapsed.marker, m) < 0))
            { collapsed = sp }
        } else if (sp.from > pos && nextChange > sp.from) {
          nextChange = sp.from
        }
      }
      if (endStyles) { for (var j$1 = 0; j$1 < endStyles.length; j$1 += 2)
        { if (endStyles[j$1 + 1] == nextChange) { spanEndStyle += " " + endStyles[j$1] } } }

      if (!collapsed || collapsed.from == pos) { for (var j$2 = 0; j$2 < foundBookmarks.length; ++j$2)
        { buildCollapsedSpan(builder, 0, foundBookmarks[j$2]) } }
      if (collapsed && (collapsed.from || 0) == pos) {
        buildCollapsedSpan(builder, (collapsed.to == null ? len + 1 : collapsed.to) - pos,
                           collapsed.marker, collapsed.from == null)
        if (collapsed.to == null) { return }
        if (collapsed.to == pos) { collapsed = false }
      }
    }
    if (pos >= len) { break }

    var upto = Math.min(len, nextChange)
    while (true) {
      if (text) {
        var end = pos + text.length
        if (!collapsed) {
          var tokenText = end > upto ? text.slice(0, upto - pos) : text
          builder.addToken(builder, tokenText, style ? style + spanStyle : spanStyle,
                           spanStartStyle, pos + tokenText.length == nextChange ? spanEndStyle : "", title, css)
        }
        if (end >= upto) {text = text.slice(upto - pos); pos = upto; break}
        pos = end
        spanStartStyle = ""
      }
      text = allText.slice(at, at = styles[i++])
      style = interpretTokenStyle(styles[i++], builder.cm.options)
    }
  }
}


// These objects are used to represent the visible (currently drawn)
// part of the document. A LineView may correspond to multiple
// logical lines, if those are connected by collapsed ranges.
function LineView(doc, line, lineN) {
  // The starting line
  this.line = line
  // Continuing lines, if any
  this.rest = visualLineContinued(line)
  // Number of logical lines in this visual line
  this.size = this.rest ? lineNo(lst(this.rest)) - lineN + 1 : 1
  this.node = this.text = null
  this.hidden = lineIsHidden(doc, line)
}

// Create a range of LineView objects for the given lines.
function buildViewArray(cm, from, to) {
  var array = [], nextPos
  for (var pos = from; pos < to; pos = nextPos) {
    var view = new LineView(cm.doc, getLine(cm.doc, pos), pos)
    nextPos = pos + view.size
    array.push(view)
  }
  return array
}

var operationGroup = null

function pushOperation(op) {
  if (operationGroup) {
    operationGroup.ops.push(op)
  } else {
    op.ownsGroup = operationGroup = {
      ops: [op],
      delayedCallbacks: []
    }
  }
}

function fireCallbacksForOps(group) {
  // Calls delayed callbacks and cursorActivity handlers until no
  // new ones appear
  var callbacks = group.delayedCallbacks, i = 0
  do {
    for (; i < callbacks.length; i++)
      { callbacks[i].call(null) }
    for (var j = 0; j < group.ops.length; j++) {
      var op = group.ops[j]
      if (op.cursorActivityHandlers)
        { while (op.cursorActivityCalled < op.cursorActivityHandlers.length)
          { op.cursorActivityHandlers[op.cursorActivityCalled++].call(null, op.cm) } }
    }
  } while (i < callbacks.length)
}

function finishOperation(op, endCb) {
  var group = op.ownsGroup
  if (!group) { return }

  try { fireCallbacksForOps(group) }
  finally {
    operationGroup = null
    endCb(group)
  }
}

var orphanDelayedCallbacks = null

// Often, we want to signal events at a point where we are in the
// middle of some work, but don't want the handler to start calling
// other methods on the editor, which might be in an inconsistent
// state or simply not expect any other events to happen.
// signalLater looks whether there are any handlers, and schedules
// them to be executed when the last operation ends, or, if no
// operation is active, when a timeout fires.
function signalLater(emitter, type /*, values...*/) {
  var arr = getHandlers(emitter, type)
  if (!arr.length) { return }
  var args = Array.prototype.slice.call(arguments, 2), list
  if (operationGroup) {
    list = operationGroup.delayedCallbacks
  } else if (orphanDelayedCallbacks) {
    list = orphanDelayedCallbacks
  } else {
    list = orphanDelayedCallbacks = []
    setTimeout(fireOrphanDelayed, 0)
  }
  var loop = function ( i ) {
    list.push(function () { return arr[i].apply(null, args); })
  };

  for (var i = 0; i < arr.length; ++i)
    loop( i );
}

function fireOrphanDelayed() {
  var delayed = orphanDelayedCallbacks
  orphanDelayedCallbacks = null
  for (var i = 0; i < delayed.length; ++i) { delayed[i]() }
}

// When an aspect of a line changes, a string is added to
// lineView.changes. This updates the relevant part of the line's
// DOM structure.
function updateLineForChanges(cm, lineView, lineN, dims) {
  for (var j = 0; j < lineView.changes.length; j++) {
    var type = lineView.changes[j]
    if (type == "text") { updateLineText(cm, lineView) }
    else if (type == "gutter") { updateLineGutter(cm, lineView, lineN, dims) }
    else if (type == "class") { updateLineClasses(cm, lineView) }
    else if (type == "widget") { updateLineWidgets(cm, lineView, dims) }
  }
  lineView.changes = null
}

// Lines with gutter elements, widgets or a background class need to
// be wrapped, and have the extra elements added to the wrapper div
function ensureLineWrapped(lineView) {
  if (lineView.node == lineView.text) {
    lineView.node = elt("div", null, null, "position: relative")
    if (lineView.text.parentNode)
      { lineView.text.parentNode.replaceChild(lineView.node, lineView.text) }
    lineView.node.appendChild(lineView.text)
    if (ie && ie_version < 8) { lineView.node.style.zIndex = 2 }
  }
  return lineView.node
}

function updateLineBackground(cm, lineView) {
  var cls = lineView.bgClass ? lineView.bgClass + " " + (lineView.line.bgClass || "") : lineView.line.bgClass
  if (cls) { cls += " CodeMirror-linebackground" }
  if (lineView.background) {
    if (cls) { lineView.background.className = cls }
    else { lineView.background.parentNode.removeChild(lineView.background); lineView.background = null }
  } else if (cls) {
    var wrap = ensureLineWrapped(lineView)
    lineView.background = wrap.insertBefore(elt("div", null, cls), wrap.firstChild)
    cm.display.input.setUneditable(lineView.background)
  }
}

// Wrapper around buildLineContent which will reuse the structure
// in display.externalMeasured when possible.
function getLineContent(cm, lineView) {
  var ext = cm.display.externalMeasured
  if (ext && ext.line == lineView.line) {
    cm.display.externalMeasured = null
    lineView.measure = ext.measure
    return ext.built
  }
  return buildLineContent(cm, lineView)
}

// Redraw the line's text. Interacts with the background and text
// classes because the mode may output tokens that influence these
// classes.
function updateLineText(cm, lineView) {
  var cls = lineView.text.className
  var built = getLineContent(cm, lineView)
  if (lineView.text == lineView.node) { lineView.node = built.pre }
  lineView.text.parentNode.replaceChild(built.pre, lineView.text)
  lineView.text = built.pre
  if (built.bgClass != lineView.bgClass || built.textClass != lineView.textClass) {
    lineView.bgClass = built.bgClass
    lineView.textClass = built.textClass
    updateLineClasses(cm, lineView)
  } else if (cls) {
    lineView.text.className = cls
  }
}

function updateLineClasses(cm, lineView) {
  updateLineBackground(cm, lineView)
  if (lineView.line.wrapClass)
    { ensureLineWrapped(lineView).className = lineView.line.wrapClass }
  else if (lineView.node != lineView.text)
    { lineView.node.className = "" }
  var textClass = lineView.textClass ? lineView.textClass + " " + (lineView.line.textClass || "") : lineView.line.textClass
  lineView.text.className = textClass || ""
}

function updateLineGutter(cm, lineView, lineN, dims) {
  if (lineView.gutter) {
    lineView.node.removeChild(lineView.gutter)
    lineView.gutter = null
  }
  if (lineView.gutterBackground) {
    lineView.node.removeChild(lineView.gutterBackground)
    lineView.gutterBackground = null
  }
  if (lineView.line.gutterClass) {
    var wrap = ensureLineWrapped(lineView)
    lineView.gutterBackground = elt("div", null, "CodeMirror-gutter-background " + lineView.line.gutterClass,
                                    ("left: " + (cm.options.fixedGutter ? dims.fixedPos : -dims.gutterTotalWidth) + "px; width: " + (dims.gutterTotalWidth) + "px"))
    cm.display.input.setUneditable(lineView.gutterBackground)
    wrap.insertBefore(lineView.gutterBackground, lineView.text)
  }
  var markers = lineView.line.gutterMarkers
  if (cm.options.lineNumbers || markers) {
    var wrap$1 = ensureLineWrapped(lineView)
    var gutterWrap = lineView.gutter = elt("div", null, "CodeMirror-gutter-wrapper", ("left: " + (cm.options.fixedGutter ? dims.fixedPos : -dims.gutterTotalWidth) + "px"))
    cm.display.input.setUneditable(gutterWrap)
    wrap$1.insertBefore(gutterWrap, lineView.text)
    if (lineView.line.gutterClass)
      { gutterWrap.className += " " + lineView.line.gutterClass }
    if (cm.options.lineNumbers && (!markers || !markers["CodeMirror-linenumbers"]))
      { lineView.lineNumber = gutterWrap.appendChild(
        elt("div", lineNumberFor(cm.options, lineN),
            "CodeMirror-linenumber CodeMirror-gutter-elt",
            ("left: " + (dims.gutterLeft["CodeMirror-linenumbers"]) + "px; width: " + (cm.display.lineNumInnerWidth) + "px"))) }
    if (markers) { for (var k = 0; k < cm.options.gutters.length; ++k) {
      var id = cm.options.gutters[k], found = markers.hasOwnProperty(id) && markers[id]
      if (found)
        { gutterWrap.appendChild(elt("div", [found], "CodeMirror-gutter-elt",
                                   ("left: " + (dims.gutterLeft[id]) + "px; width: " + (dims.gutterWidth[id]) + "px"))) }
    } }
  }
}

function updateLineWidgets(cm, lineView, dims) {
  if (lineView.alignable) { lineView.alignable = null }
  for (var node = lineView.node.firstChild, next = (void 0); node; node = next) {
    next = node.nextSibling
    if (node.className == "CodeMirror-linewidget")
      { lineView.node.removeChild(node) }
  }
  insertLineWidgets(cm, lineView, dims)
}

// Build a line's DOM representation from scratch
function buildLineElement(cm, lineView, lineN, dims) {
  var built = getLineContent(cm, lineView)
  lineView.text = lineView.node = built.pre
  if (built.bgClass) { lineView.bgClass = built.bgClass }
  if (built.textClass) { lineView.textClass = built.textClass }

  updateLineClasses(cm, lineView)
  updateLineGutter(cm, lineView, lineN, dims)
  insertLineWidgets(cm, lineView, dims)
  return lineView.node
}

// A lineView may contain multiple logical lines (when merged by
// collapsed spans). The widgets for all of them need to be drawn.
function insertLineWidgets(cm, lineView, dims) {
  insertLineWidgetsFor(cm, lineView.line, lineView, dims, true)
  if (lineView.rest) { for (var i = 0; i < lineView.rest.length; i++)
    { insertLineWidgetsFor(cm, lineView.rest[i], lineView, dims, false) } }
}

function insertLineWidgetsFor(cm, line, lineView, dims, allowAbove) {
  if (!line.widgets) { return }
  var wrap = ensureLineWrapped(lineView)
  for (var i = 0, ws = line.widgets; i < ws.length; ++i) {
    var widget = ws[i], node = elt("div", [widget.node], "CodeMirror-linewidget")
    if (!widget.handleMouseEvents) { node.setAttribute("cm-ignore-events", "true") }
    positionLineWidget(widget, node, lineView, dims)
    cm.display.input.setUneditable(node)
    if (allowAbove && widget.above)
      { wrap.insertBefore(node, lineView.gutter || lineView.text) }
    else
      { wrap.appendChild(node) }
    signalLater(widget, "redraw")
  }
}

function positionLineWidget(widget, node, lineView, dims) {
  if (widget.noHScroll) {
    ;(lineView.alignable || (lineView.alignable = [])).push(node)
    var width = dims.wrapperWidth
    node.style.left = dims.fixedPos + "px"
    if (!widget.coverGutter) {
      width -= dims.gutterTotalWidth
      node.style.paddingLeft = dims.gutterTotalWidth + "px"
    }
    node.style.width = width + "px"
  }
  if (widget.coverGutter) {
    node.style.zIndex = 5
    node.style.position = "relative"
    if (!widget.noHScroll) { node.style.marginLeft = -dims.gutterTotalWidth + "px" }
  }
}

function widgetHeight(widget) {
  if (widget.height != null) { return widget.height }
  var cm = widget.doc.cm
  if (!cm) { return 0 }
  if (!contains(document.body, widget.node)) {
    var parentStyle = "position: relative;"
    if (widget.coverGutter)
      { parentStyle += "margin-left: -" + cm.display.gutters.offsetWidth + "px;" }
    if (widget.noHScroll)
      { parentStyle += "width: " + cm.display.wrapper.clientWidth + "px;" }
    removeChildrenAndAdd(cm.display.measure, elt("div", [widget.node], null, parentStyle))
  }
  return widget.height = widget.node.parentNode.offsetHeight
}

// Return true when the given mouse event happened in a widget
function eventInWidget(display, e) {
  for (var n = e_target(e); n != display.wrapper; n = n.parentNode) {
    if (!n || (n.nodeType == 1 && n.getAttribute("cm-ignore-events") == "true") ||
        (n.parentNode == display.sizer && n != display.mover))
      { return true }
  }
}

// POSITION MEASUREMENT

function paddingTop(display) {return display.lineSpace.offsetTop}
function paddingVert(display) {return display.mover.offsetHeight - display.lineSpace.offsetHeight}
function paddingH(display) {
  if (display.cachedPaddingH) { return display.cachedPaddingH }
  var e = removeChildrenAndAdd(display.measure, elt("pre", "x"))
  var style = window.getComputedStyle ? window.getComputedStyle(e) : e.currentStyle
  var data = {left: parseInt(style.paddingLeft), right: parseInt(style.paddingRight)}
  if (!isNaN(data.left) && !isNaN(data.right)) { display.cachedPaddingH = data }
  return data
}

function scrollGap(cm) { return scrollerGap - cm.display.nativeBarWidth }
function displayWidth(cm) {
  return cm.display.scroller.clientWidth - scrollGap(cm) - cm.display.barWidth
}
function displayHeight(cm) {
  return cm.display.scroller.clientHeight - scrollGap(cm) - cm.display.barHeight
}

// Ensure the lineView.wrapping.heights array is populated. This is
// an array of bottom offsets for the lines that make up a drawn
// line. When lineWrapping is on, there might be more than one
// height.
function ensureLineHeights(cm, lineView, rect) {
  var wrapping = cm.options.lineWrapping
  var curWidth = wrapping && displayWidth(cm)
  if (!lineView.measure.heights || wrapping && lineView.measure.width != curWidth) {
    var heights = lineView.measure.heights = []
    if (wrapping) {
      lineView.measure.width = curWidth
      var rects = lineView.text.firstChild.getClientRects()
      for (var i = 0; i < rects.length - 1; i++) {
        var cur = rects[i], next = rects[i + 1]
        if (Math.abs(cur.bottom - next.bottom) > 2)
          { heights.push((cur.bottom + next.top) / 2 - rect.top) }
      }
    }
    heights.push(rect.bottom - rect.top)
  }
}

// Find a line map (mapping character offsets to text nodes) and a
// measurement cache for the given line number. (A line view might
// contain multiple lines when collapsed ranges are present.)
function mapFromLineView(lineView, line, lineN) {
  if (lineView.line == line)
    { return {map: lineView.measure.map, cache: lineView.measure.cache} }
  for (var i = 0; i < lineView.rest.length; i++)
    { if (lineView.rest[i] == line)
      { return {map: lineView.measure.maps[i], cache: lineView.measure.caches[i]} } }
  for (var i$1 = 0; i$1 < lineView.rest.length; i$1++)
    { if (lineNo(lineView.rest[i$1]) > lineN)
      { return {map: lineView.measure.maps[i$1], cache: lineView.measure.caches[i$1], before: true} } }
}

// Render a line into the hidden node display.externalMeasured. Used
// when measurement is needed for a line that's not in the viewport.
function updateExternalMeasurement(cm, line) {
  line = visualLine(line)
  var lineN = lineNo(line)
  var view = cm.display.externalMeasured = new LineView(cm.doc, line, lineN)
  view.lineN = lineN
  var built = view.built = buildLineContent(cm, view)
  view.text = built.pre
  removeChildrenAndAdd(cm.display.lineMeasure, built.pre)
  return view
}

// Get a {top, bottom, left, right} box (in line-local coordinates)
// for a given character.
function measureChar(cm, line, ch, bias) {
  return measureCharPrepared(cm, prepareMeasureForLine(cm, line), ch, bias)
}

// Find a line view that corresponds to the given line number.
function findViewForLine(cm, lineN) {
  if (lineN >= cm.display.viewFrom && lineN < cm.display.viewTo)
    { return cm.display.view[findViewIndex(cm, lineN)] }
  var ext = cm.display.externalMeasured
  if (ext && lineN >= ext.lineN && lineN < ext.lineN + ext.size)
    { return ext }
}

// Measurement can be split in two steps, the set-up work that
// applies to the whole line, and the measurement of the actual
// character. Functions like coordsChar, that need to do a lot of
// measurements in a row, can thus ensure that the set-up work is
// only done once.
function prepareMeasureForLine(cm, line) {
  var lineN = lineNo(line)
  var view = findViewForLine(cm, lineN)
  if (view && !view.text) {
    view = null
  } else if (view && view.changes) {
    updateLineForChanges(cm, view, lineN, getDimensions(cm))
    cm.curOp.forceUpdate = true
  }
  if (!view)
    { view = updateExternalMeasurement(cm, line) }

  var info = mapFromLineView(view, line, lineN)
  return {
    line: line, view: view, rect: null,
    map: info.map, cache: info.cache, before: info.before,
    hasHeights: false
  }
}

// Given a prepared measurement object, measures the position of an
// actual character (or fetches it from the cache).
function measureCharPrepared(cm, prepared, ch, bias, varHeight) {
  if (prepared.before) { ch = -1 }
  var key = ch + (bias || ""), found
  if (prepared.cache.hasOwnProperty(key)) {
    found = prepared.cache[key]
  } else {
    if (!prepared.rect)
      { prepared.rect = prepared.view.text.getBoundingClientRect() }
    if (!prepared.hasHeights) {
      ensureLineHeights(cm, prepared.view, prepared.rect)
      prepared.hasHeights = true
    }
    found = measureCharInner(cm, prepared, ch, bias)
    if (!found.bogus) { prepared.cache[key] = found }
  }
  return {left: found.left, right: found.right,
          top: varHeight ? found.rtop : found.top,
          bottom: varHeight ? found.rbottom : found.bottom}
}

var nullRect = {left: 0, right: 0, top: 0, bottom: 0}

function nodeAndOffsetInLineMap(map, ch, bias) {
  var node, start, end, collapse, mStart, mEnd
  // First, search the line map for the text node corresponding to,
  // or closest to, the target character.
  for (var i = 0; i < map.length; i += 3) {
    mStart = map[i]
    mEnd = map[i + 1]
    if (ch < mStart) {
      start = 0; end = 1
      collapse = "left"
    } else if (ch < mEnd) {
      start = ch - mStart
      end = start + 1
    } else if (i == map.length - 3 || ch == mEnd && map[i + 3] > ch) {
      end = mEnd - mStart
      start = end - 1
      if (ch >= mEnd) { collapse = "right" }
    }
    if (start != null) {
      node = map[i + 2]
      if (mStart == mEnd && bias == (node.insertLeft ? "left" : "right"))
        { collapse = bias }
      if (bias == "left" && start == 0)
        { while (i && map[i - 2] == map[i - 3] && map[i - 1].insertLeft) {
          node = map[(i -= 3) + 2]
          collapse = "left"
        } }
      if (bias == "right" && start == mEnd - mStart)
        { while (i < map.length - 3 && map[i + 3] == map[i + 4] && !map[i + 5].insertLeft) {
          node = map[(i += 3) + 2]
          collapse = "right"
        } }
      break
    }
  }
  return {node: node, start: start, end: end, collapse: collapse, coverStart: mStart, coverEnd: mEnd}
}

function getUsefulRect(rects, bias) {
  var rect = nullRect
  if (bias == "left") { for (var i = 0; i < rects.length; i++) {
    if ((rect = rects[i]).left != rect.right) { break }
  } } else { for (var i$1 = rects.length - 1; i$1 >= 0; i$1--) {
    if ((rect = rects[i$1]).left != rect.right) { break }
  } }
  return rect
}

function measureCharInner(cm, prepared, ch, bias) {
  var place = nodeAndOffsetInLineMap(prepared.map, ch, bias)
  var node = place.node, start = place.start, end = place.end, collapse = place.collapse

  var rect
  if (node.nodeType == 3) { // If it is a text node, use a range to retrieve the coordinates.
    for (var i$1 = 0; i$1 < 4; i$1++) { // Retry a maximum of 4 times when nonsense rectangles are returned
      while (start && isExtendingChar(prepared.line.text.charAt(place.coverStart + start))) { --start }
      while (place.coverStart + end < place.coverEnd && isExtendingChar(prepared.line.text.charAt(place.coverStart + end))) { ++end }
      if (ie && ie_version < 9 && start == 0 && end == place.coverEnd - place.coverStart)
        { rect = node.parentNode.getBoundingClientRect() }
      else
        { rect = getUsefulRect(range(node, start, end).getClientRects(), bias) }
      if (rect.left || rect.right || start == 0) { break }
      end = start
      start = start - 1
      collapse = "right"
    }
    if (ie && ie_version < 11) { rect = maybeUpdateRectForZooming(cm.display.measure, rect) }
  } else { // If it is a widget, simply get the box for the whole widget.
    if (start > 0) { collapse = bias = "right" }
    var rects
    if (cm.options.lineWrapping && (rects = node.getClientRects()).length > 1)
      { rect = rects[bias == "right" ? rects.length - 1 : 0] }
    else
      { rect = node.getBoundingClientRect() }
  }
  if (ie && ie_version < 9 && !start && (!rect || !rect.left && !rect.right)) {
    var rSpan = node.parentNode.getClientRects()[0]
    if (rSpan)
      { rect = {left: rSpan.left, right: rSpan.left + charWidth(cm.display), top: rSpan.top, bottom: rSpan.bottom} }
    else
      { rect = nullRect }
  }

  var rtop = rect.top - prepared.rect.top, rbot = rect.bottom - prepared.rect.top
  var mid = (rtop + rbot) / 2
  var heights = prepared.view.measure.heights
  var i = 0
  for (; i < heights.length - 1; i++)
    { if (mid < heights[i]) { break } }
  var top = i ? heights[i - 1] : 0, bot = heights[i]
  var result = {left: (collapse == "right" ? rect.right : rect.left) - prepared.rect.left,
                right: (collapse == "left" ? rect.left : rect.right) - prepared.rect.left,
                top: top, bottom: bot}
  if (!rect.left && !rect.right) { result.bogus = true }
  if (!cm.options.singleCursorHeightPerLine) { result.rtop = rtop; result.rbottom = rbot }

  return result
}

// Work around problem with bounding client rects on ranges being
// returned incorrectly when zoomed on IE10 and below.
function maybeUpdateRectForZooming(measure, rect) {
  if (!window.screen || screen.logicalXDPI == null ||
      screen.logicalXDPI == screen.deviceXDPI || !hasBadZoomedRects(measure))
    { return rect }
  var scaleX = screen.logicalXDPI / screen.deviceXDPI
  var scaleY = screen.logicalYDPI / screen.deviceYDPI
  return {left: rect.left * scaleX, right: rect.right * scaleX,
          top: rect.top * scaleY, bottom: rect.bottom * scaleY}
}

function clearLineMeasurementCacheFor(lineView) {
  if (lineView.measure) {
    lineView.measure.cache = {}
    lineView.measure.heights = null
    if (lineView.rest) { for (var i = 0; i < lineView.rest.length; i++)
      { lineView.measure.caches[i] = {} } }
  }
}

function clearLineMeasurementCache(cm) {
  cm.display.externalMeasure = null
  removeChildren(cm.display.lineMeasure)
  for (var i = 0; i < cm.display.view.length; i++)
    { clearLineMeasurementCacheFor(cm.display.view[i]) }
}

function clearCaches(cm) {
  clearLineMeasurementCache(cm)
  cm.display.cachedCharWidth = cm.display.cachedTextHeight = cm.display.cachedPaddingH = null
  if (!cm.options.lineWrapping) { cm.display.maxLineChanged = true }
  cm.display.lineNumChars = null
}

function pageScrollX() {
  // Work around https://bugs.chromium.org/p/chromium/issues/detail?id=489206
  // which causes page_Offset and bounding client rects to use
  // different reference viewports and invalidate our calculations.
  if (chrome && android) { return -(document.body.getBoundingClientRect().left - parseInt(getComputedStyle(document.body).marginLeft)) }
  return window.pageXOffset || (document.documentElement || document.body).scrollLeft
}
function pageScrollY() {
  if (chrome && android) { return -(document.body.getBoundingClientRect().top - parseInt(getComputedStyle(document.body).marginTop)) }
  return window.pageYOffset || (document.documentElement || document.body).scrollTop
}

function widgetTopHeight(lineObj) {
  var height = 0
  if (lineObj.widgets) { for (var i = 0; i < lineObj.widgets.length; ++i) { if (lineObj.widgets[i].above)
    { height += widgetHeight(lineObj.widgets[i]) } } }
  return height
}

// Converts a {top, bottom, left, right} box from line-local
// coordinates into another coordinate system. Context may be one of
// "line", "div" (display.lineDiv), "local"./null (editor), "window",
// or "page".
function intoCoordSystem(cm, lineObj, rect, context, includeWidgets) {
  if (!includeWidgets) {
    var height = widgetTopHeight(lineObj)
    rect.top += height; rect.bottom += height
  }
  if (context == "line") { return rect }
  if (!context) { context = "local" }
  var yOff = heightAtLine(lineObj)
  if (context == "local") { yOff += paddingTop(cm.display) }
  else { yOff -= cm.display.viewOffset }
  if (context == "page" || context == "window") {
    var lOff = cm.display.lineSpace.getBoundingClientRect()
    yOff += lOff.top + (context == "window" ? 0 : pageScrollY())
    var xOff = lOff.left + (context == "window" ? 0 : pageScrollX())
    rect.left += xOff; rect.right += xOff
  }
  rect.top += yOff; rect.bottom += yOff
  return rect
}

// Coverts a box from "div" coords to another coordinate system.
// Context may be "window", "page", "div", or "local"./null.
function fromCoordSystem(cm, coords, context) {
  if (context == "div") { return coords }
  var left = coords.left, top = coords.top
  // First move into "page" coordinate system
  if (context == "page") {
    left -= pageScrollX()
    top -= pageScrollY()
  } else if (context == "local" || !context) {
    var localBox = cm.display.sizer.getBoundingClientRect()
    left += localBox.left
    top += localBox.top
  }

  var lineSpaceBox = cm.display.lineSpace.getBoundingClientRect()
  return {left: left - lineSpaceBox.left, top: top - lineSpaceBox.top}
}

function charCoords(cm, pos, context, lineObj, bias) {
  if (!lineObj) { lineObj = getLine(cm.doc, pos.line) }
  return intoCoordSystem(cm, lineObj, measureChar(cm, lineObj, pos.ch, bias), context)
}

// Returns a box for a given cursor position, which may have an
// 'other' property containing the position of the secondary cursor
// on a bidi boundary.
// A cursor Pos(line, char, "before") is on the same visual line as `char - 1`
// and after `char - 1` in writing order of `char - 1`
// A cursor Pos(line, char, "after") is on the same visual line as `char`
// and before `char` in writing order of `char`
// Examples (upper-case letters are RTL, lower-case are LTR):
//     Pos(0, 1, ...)
//     before   after
// ab     a|b     a|b
// aB     a|B     aB|
// Ab     |Ab     A|b
// AB     B|A     B|A
// Every position after the last character on a line is considered to stick
// to the last character on the line.
function cursorCoords(cm, pos, context, lineObj, preparedMeasure, varHeight) {
  lineObj = lineObj || getLine(cm.doc, pos.line)
  if (!preparedMeasure) { preparedMeasure = prepareMeasureForLine(cm, lineObj) }
  function get(ch, right) {
    var m = measureCharPrepared(cm, preparedMeasure, ch, right ? "right" : "left", varHeight)
    if (right) { m.left = m.right; } else { m.right = m.left }
    return intoCoordSystem(cm, lineObj, m, context)
  }
  var order = getOrder(lineObj, cm.doc.direction), ch = pos.ch, sticky = pos.sticky
  if (ch >= lineObj.text.length) {
    ch = lineObj.text.length
    sticky = "before"
  } else if (ch <= 0) {
    ch = 0
    sticky = "after"
  }
  if (!order) { return get(sticky == "before" ? ch - 1 : ch, sticky == "before") }

  function getBidi(ch, partPos, invert) {
    var part = order[partPos], right = part.level == 1
    return get(invert ? ch - 1 : ch, right != invert)
  }
  var partPos = getBidiPartAt(order, ch, sticky)
  var other = bidiOther
  var val = getBidi(ch, partPos, sticky == "before")
  if (other != null) { val.other = getBidi(ch, other, sticky != "before") }
  return val
}

// Used to cheaply estimate the coordinates for a position. Used for
// intermediate scroll updates.
function estimateCoords(cm, pos) {
  var left = 0
  pos = clipPos(cm.doc, pos)
  if (!cm.options.lineWrapping) { left = charWidth(cm.display) * pos.ch }
  var lineObj = getLine(cm.doc, pos.line)
  var top = heightAtLine(lineObj) + paddingTop(cm.display)
  return {left: left, right: left, top: top, bottom: top + lineObj.height}
}

// Positions returned by coordsChar contain some extra information.
// xRel is the relative x position of the input coordinates compared
// to the found position (so xRel > 0 means the coordinates are to
// the right of the character position, for example). When outside
// is true, that means the coordinates lie outside the line's
// vertical range.
function PosWithInfo(line, ch, sticky, outside, xRel) {
  var pos = Pos(line, ch, sticky)
  pos.xRel = xRel
  if (outside) { pos.outside = true }
  return pos
}

// Compute the character position closest to the given coordinates.
// Input must be lineSpace-local ("div" coordinate system).
function coordsChar(cm, x, y) {
  var doc = cm.doc
  y += cm.display.viewOffset
  if (y < 0) { return PosWithInfo(doc.first, 0, null, true, -1) }
  var lineN = lineAtHeight(doc, y), last = doc.first + doc.size - 1
  if (lineN > last)
    { return PosWithInfo(doc.first + doc.size - 1, getLine(doc, last).text.length, null, true, 1) }
  if (x < 0) { x = 0 }

  var lineObj = getLine(doc, lineN)
  for (;;) {
    var found = coordsCharInner(cm, lineObj, lineN, x, y)
    var collapsed = collapsedSpanAround(lineObj, found.ch + (found.xRel > 0 ? 1 : 0))
    if (!collapsed) { return found }
    var rangeEnd = collapsed.find(1)
    if (rangeEnd.line == lineN) { return rangeEnd }
    lineObj = getLine(doc, lineN = rangeEnd.line)
  }
}

function wrappedLineExtent(cm, lineObj, preparedMeasure, y) {
  y -= widgetTopHeight(lineObj)
  var end = lineObj.text.length
  var begin = findFirst(function (ch) { return measureCharPrepared(cm, preparedMeasure, ch - 1).bottom <= y; }, end, 0)
  end = findFirst(function (ch) { return measureCharPrepared(cm, preparedMeasure, ch).top > y; }, begin, end)
  return {begin: begin, end: end}
}

function wrappedLineExtentChar(cm, lineObj, preparedMeasure, target) {
  if (!preparedMeasure) { preparedMeasure = prepareMeasureForLine(cm, lineObj) }
  var targetTop = intoCoordSystem(cm, lineObj, measureCharPrepared(cm, preparedMeasure, target), "line").top
  return wrappedLineExtent(cm, lineObj, preparedMeasure, targetTop)
}

// Returns true if the given side of a box is after the given
// coordinates, in top-to-bottom, left-to-right order.
function boxIsAfter(box, x, y, left) {
  return box.bottom <= y ? false : box.top > y ? true : (left ? box.left : box.right) > x
}

function coordsCharInner(cm, lineObj, lineNo, x, y) {
  // Move y into line-local coordinate space
  y -= heightAtLine(lineObj)
  var preparedMeasure = prepareMeasureForLine(cm, lineObj)
  // When directly calling `measureCharPrepared`, we have to adjust
  // for the widgets at this line.
  var widgetHeight = widgetTopHeight(lineObj)
  var begin = 0, end = lineObj.text.length, ltr = true

  var order = getOrder(lineObj, cm.doc.direction)
  // If the line isn't plain left-to-right text, first figure out
  // which bidi section the coordinates fall into.
  if (order) {
    var part = (cm.options.lineWrapping ? coordsBidiPartWrapped : coordsBidiPart)
                 (cm, lineObj, lineNo, preparedMeasure, order, x, y)
    ltr = part.level != 1
    // The awkward -1 offsets are needed because findFirst (called
    // on these below) will treat its first bound as inclusive,
    // second as exclusive, but we want to actually address the
    // characters in the part's range
    begin = ltr ? part.from : part.to - 1
    end = ltr ? part.to : part.from - 1
  }

  // A binary search to find the first character whose bounding box
  // starts after the coordinates. If we run across any whose box wrap
  // the coordinates, store that.
  var chAround = null, boxAround = null
  var ch = findFirst(function (ch) {
    var box = measureCharPrepared(cm, preparedMeasure, ch)
    box.top += widgetHeight; box.bottom += widgetHeight
    if (!boxIsAfter(box, x, y, false)) { return false }
    if (box.top <= y && box.left <= x) {
      chAround = ch
      boxAround = box
    }
    return true
  }, begin, end)

  var baseX, sticky, outside = false
  // If a box around the coordinates was found, use that
  if (boxAround) {
    // Distinguish coordinates nearer to the left or right side of the box
    var atLeft = x - boxAround.left < boxAround.right - x, atStart = atLeft == ltr
    ch = chAround + (atStart ? 0 : 1)
    sticky = atStart ? "after" : "before"
    baseX = atLeft ? boxAround.left : boxAround.right
  } else {
    // (Adjust for extended bound, if necessary.)
    if (!ltr && (ch == end || ch == begin)) { ch++ }
    // To determine which side to associate with, get the box to the
    // left of the character and compare it's vertical position to the
    // coordinates
    sticky = ch == 0 ? "after" : ch == lineObj.text.length ? "before" :
      (measureCharPrepared(cm, preparedMeasure, ch - (ltr ? 1 : 0)).bottom + widgetHeight <= y) == ltr ?
      "after" : "before"
    // Now get accurate coordinates for this place, in order to get a
    // base X position
    var coords = cursorCoords(cm, Pos(lineNo, ch, sticky), "line", lineObj, preparedMeasure)
    baseX = coords.left
    outside = y < coords.top || y >= coords.bottom
  }

  ch = skipExtendingChars(lineObj.text, ch, 1)
  return PosWithInfo(lineNo, ch, sticky, outside, x - baseX)
}

function coordsBidiPart(cm, lineObj, lineNo, preparedMeasure, order, x, y) {
  // Bidi parts are sorted left-to-right, and in a non-line-wrapping
  // situation, we can take this ordering to correspond to the visual
  // ordering. This finds the first part whose end is after the given
  // coordinates.
  var index = findFirst(function (i) {
    var part = order[i], ltr = part.level != 1
    return boxIsAfter(cursorCoords(cm, Pos(lineNo, ltr ? part.to : part.from, ltr ? "before" : "after"),
                                   "line", lineObj, preparedMeasure), x, y, true)
  }, 0, order.length - 1)
  var part = order[index]
  // If this isn't the first part, the part's start is also after
  // the coordinates, and the coordinates aren't on the same line as
  // that start, move one part back.
  if (index > 0) {
    var ltr = part.level != 1
    var start = cursorCoords(cm, Pos(lineNo, ltr ? part.from : part.to, ltr ? "after" : "before"),
                             "line", lineObj, preparedMeasure)
    if (boxIsAfter(start, x, y, true) && start.top > y)
      { part = order[index - 1] }
  }
  return part
}

function coordsBidiPartWrapped(cm, lineObj, _lineNo, preparedMeasure, order, x, y) {
  // In a wrapped line, rtl text on wrapping boundaries can do things
  // that don't correspond to the ordering in our `order` array at
  // all, so a binary search doesn't work, and we want to return a
  // part that only spans one line so that the binary search in
  // coordsCharInner is safe. As such, we first find the extent of the
  // wrapped line, and then do a flat search in which we discard any
  // spans that aren't on the line.
  var ref = wrappedLineExtent(cm, lineObj, preparedMeasure, y);
  var begin = ref.begin;
  var end = ref.end;
  if (/\s/.test(lineObj.text.charAt(end - 1))) { end-- }
  var part = null, closestDist = null
  for (var i = 0; i < order.length; i++) {
    var p = order[i]
    if (p.from >= end || p.to <= begin) { continue }
    var ltr = p.level != 1
    var endX = measureCharPrepared(cm, preparedMeasure, ltr ? Math.min(end, p.to) - 1 : Math.max(begin, p.from)).right
    // Weigh against spans ending before this, so that they are only
    // picked if nothing ends after
    var dist = endX < x ? x - endX + 1e9 : endX - x
    if (!part || closestDist > dist) {
      part = p
      closestDist = dist
    }
  }
  if (!part) { part = order[order.length - 1] }
  // Clip the part to the wrapped line.
  if (part.from < begin) { part = {from: begin, to: part.to, level: part.level} }
  if (part.to > end) { part = {from: part.from, to: end, level: part.level} }
  return part
}

var measureText
// Compute the default text height.
function textHeight(display) {
  if (display.cachedTextHeight != null) { return display.cachedTextHeight }
  if (measureText == null) {
    measureText = elt("pre")
    // Measure a bunch of lines, for browsers that compute
    // fractional heights.
    for (var i = 0; i < 49; ++i) {
      measureText.appendChild(document.createTextNode("x"))
      measureText.appendChild(elt("br"))
    }
    measureText.appendChild(document.createTextNode("x"))
  }
  removeChildrenAndAdd(display.measure, measureText)
  var height = measureText.offsetHeight / 50
  if (height > 3) { display.cachedTextHeight = height }
  removeChildren(display.measure)
  return height || 1
}

// Compute the default character width.
function charWidth(display) {
  if (display.cachedCharWidth != null) { return display.cachedCharWidth }
  var anchor = elt("span", "xxxxxxxxxx")
  var pre = elt("pre", [anchor])
  removeChildrenAndAdd(display.measure, pre)
  var rect = anchor.getBoundingClientRect(), width = (rect.right - rect.left) / 10
  if (width > 2) { display.cachedCharWidth = width }
  return width || 10
}

// Do a bulk-read of the DOM positions and sizes needed to draw the
// view, so that we don't interleave reading and writing to the DOM.
function getDimensions(cm) {
  var d = cm.display, left = {}, width = {}
  var gutterLeft = d.gutters.clientLeft
  for (var n = d.gutters.firstChild, i = 0; n; n = n.nextSibling, ++i) {
    left[cm.options.gutters[i]] = n.offsetLeft + n.clientLeft + gutterLeft
    width[cm.options.gutters[i]] = n.clientWidth
  }
  return {fixedPos: compensateForHScroll(d),
          gutterTotalWidth: d.gutters.offsetWidth,
          gutterLeft: left,
          gutterWidth: width,
          wrapperWidth: d.wrapper.clientWidth}
}

// Computes display.scroller.scrollLeft + display.gutters.offsetWidth,
// but using getBoundingClientRect to get a sub-pixel-accurate
// result.
function compensateForHScroll(display) {
  return display.scroller.getBoundingClientRect().left - display.sizer.getBoundingClientRect().left
}

// Returns a function that estimates the height of a line, to use as
// first approximation until the line becomes visible (and is thus
// properly measurable).
function estimateHeight(cm) {
  var th = textHeight(cm.display), wrapping = cm.options.lineWrapping
  var perLine = wrapping && Math.max(5, cm.display.scroller.clientWidth / charWidth(cm.display) - 3)
  return function (line) {
    if (lineIsHidden(cm.doc, line)) { return 0 }

    var widgetsHeight = 0
    if (line.widgets) { for (var i = 0; i < line.widgets.length; i++) {
      if (line.widgets[i].height) { widgetsHeight += line.widgets[i].height }
    } }

    if (wrapping)
      { return widgetsHeight + (Math.ceil(line.text.length / perLine) || 1) * th }
    else
      { return widgetsHeight + th }
  }
}

function estimateLineHeights(cm) {
  var doc = cm.doc, est = estimateHeight(cm)
  doc.iter(function (line) {
    var estHeight = est(line)
    if (estHeight != line.height) { updateLineHeight(line, estHeight) }
  })
}

// Given a mouse event, find the corresponding position. If liberal
// is false, it checks whether a gutter or scrollbar was clicked,
// and returns null if it was. forRect is used by rectangular
// selections, and tries to estimate a character position even for
// coordinates beyond the right of the text.
function posFromMouse(cm, e, liberal, forRect) {
  var display = cm.display
  if (!liberal && e_target(e).getAttribute("cm-not-content") == "true") { return null }

  var x, y, space = display.lineSpace.getBoundingClientRect()
  // Fails unpredictably on IE[67] when mouse is dragged around quickly.
  try { x = e.clientX - space.left; y = e.clientY - space.top }
  catch (e) { return null }
  var coords = coordsChar(cm, x, y), line
  if (forRect && coords.xRel == 1 && (line = getLine(cm.doc, coords.line).text).length == coords.ch) {
    var colDiff = countColumn(line, line.length, cm.options.tabSize) - line.length
    coords = Pos(coords.line, Math.max(0, Math.round((x - paddingH(cm.display).left) / charWidth(cm.display)) - colDiff))
  }
  return coords
}

// Find the view element corresponding to a given line. Return null
// when the line isn't visible.
function findViewIndex(cm, n) {
  if (n >= cm.display.viewTo) { return null }
  n -= cm.display.viewFrom
  if (n < 0) { return null }
  var view = cm.display.view
  for (var i = 0; i < view.length; i++) {
    n -= view[i].size
    if (n < 0) { return i }
  }
}

function updateSelection(cm) {
  cm.display.input.showSelection(cm.display.input.prepareSelection())
}

function prepareSelection(cm, primary) {
  if ( primary === void 0 ) primary = true;

  var doc = cm.doc, result = {}
  var curFragment = result.cursors = document.createDocumentFragment()
  var selFragment = result.selection = document.createDocumentFragment()

  for (var i = 0; i < doc.sel.ranges.length; i++) {
    if (!primary && i == doc.sel.primIndex) { continue }
    var range = doc.sel.ranges[i]
    if (range.from().line >= cm.display.viewTo || range.to().line < cm.display.viewFrom) { continue }
    var collapsed = range.empty()
    if (collapsed || cm.options.showCursorWhenSelecting)
      { drawSelectionCursor(cm, range.head, curFragment) }
    if (!collapsed)
      { drawSelectionRange(cm, range, selFragment) }
  }
  return result
}

// Draws a cursor for the given range
function drawSelectionCursor(cm, head, output) {
  var pos = cursorCoords(cm, head, "div", null, null, !cm.options.singleCursorHeightPerLine)

  var cursor = output.appendChild(elt("div", "\u00a0", "CodeMirror-cursor"))
  cursor.style.left = pos.left + "px"
  cursor.style.top = pos.top + "px"
  cursor.style.height = Math.max(0, pos.bottom - pos.top) * cm.options.cursorHeight + "px"

  if (pos.other) {
    // Secondary cursor, shown when on a 'jump' in bi-directional text
    var otherCursor = output.appendChild(elt("div", "\u00a0", "CodeMirror-cursor CodeMirror-secondarycursor"))
    otherCursor.style.display = ""
    otherCursor.style.left = pos.other.left + "px"
    otherCursor.style.top = pos.other.top + "px"
    otherCursor.style.height = (pos.other.bottom - pos.other.top) * .85 + "px"
  }
}

function cmpCoords(a, b) { return a.top - b.top || a.left - b.left }

// Draws the given range as a highlighted selection
function drawSelectionRange(cm, range, output) {
  var display = cm.display, doc = cm.doc
  var fragment = document.createDocumentFragment()
  var padding = paddingH(cm.display), leftSide = padding.left
  var rightSide = Math.max(display.sizerWidth, displayWidth(cm) - display.sizer.offsetLeft) - padding.right
  var docLTR = doc.direction == "ltr"

  function add(left, top, width, bottom) {
    if (top < 0) { top = 0 }
    top = Math.round(top)
    bottom = Math.round(bottom)
    fragment.appendChild(elt("div", null, "CodeMirror-selected", ("position: absolute; left: " + left + "px;\n                             top: " + top + "px; width: " + (width == null ? rightSide - left : width) + "px;\n                             height: " + (bottom - top) + "px")))
  }

  function drawForLine(line, fromArg, toArg) {
    var lineObj = getLine(doc, line)
    var lineLen = lineObj.text.length
    var start, end
    function coords(ch, bias) {
      return charCoords(cm, Pos(line, ch), "div", lineObj, bias)
    }

    function wrapX(pos, dir, side) {
      var extent = wrappedLineExtentChar(cm, lineObj, null, pos)
      var prop = (dir == "ltr") == (side == "after") ? "left" : "right"
      var ch = side == "after" ? extent.begin : extent.end - (/\s/.test(lineObj.text.charAt(extent.end - 1)) ? 2 : 1)
      return coords(ch, prop)[prop]
    }

    var order = getOrder(lineObj, doc.direction)
    iterateBidiSections(order, fromArg || 0, toArg == null ? lineLen : toArg, function (from, to, dir, i) {
      var ltr = dir == "ltr"
      var fromPos = coords(from, ltr ? "left" : "right")
      var toPos = coords(to - 1, ltr ? "right" : "left")

      var openStart = fromArg == null && from == 0, openEnd = toArg == null && to == lineLen
      var first = i == 0, last = !order || i == order.length - 1
      if (toPos.top - fromPos.top <= 3) { // Single line
        var openLeft = (docLTR ? openStart : openEnd) && first
        var openRight = (docLTR ? openEnd : openStart) && last
        var left = openLeft ? leftSide : (ltr ? fromPos : toPos).left
        var right = openRight ? rightSide : (ltr ? toPos : fromPos).right
        add(left, fromPos.top, right - left, fromPos.bottom)
      } else { // Multiple lines
        var topLeft, topRight, botLeft, botRight
        if (ltr) {
          topLeft = docLTR && openStart && first ? leftSide : fromPos.left
          topRight = docLTR ? rightSide : wrapX(from, dir, "before")
          botLeft = docLTR ? leftSide : wrapX(to, dir, "after")
          botRight = docLTR && openEnd && last ? rightSide : toPos.right
        } else {
          topLeft = !docLTR ? leftSide : wrapX(from, dir, "before")
          topRight = !docLTR && openStart && first ? rightSide : fromPos.right
          botLeft = !docLTR && openEnd && last ? leftSide : toPos.left
          botRight = !docLTR ? rightSide : wrapX(to, dir, "after")
        }
        add(topLeft, fromPos.top, topRight - topLeft, fromPos.bottom)
        if (fromPos.bottom < toPos.top) { add(leftSide, fromPos.bottom, null, toPos.top) }
        add(botLeft, toPos.top, botRight - botLeft, toPos.bottom)
      }

      if (!start || cmpCoords(fromPos, start) < 0) { start = fromPos }
      if (cmpCoords(toPos, start) < 0) { start = toPos }
      if (!end || cmpCoords(fromPos, end) < 0) { end = fromPos }
      if (cmpCoords(toPos, end) < 0) { end = toPos }
    })
    return {start: start, end: end}
  }

  var sFrom = range.from(), sTo = range.to()
  if (sFrom.line == sTo.line) {
    drawForLine(sFrom.line, sFrom.ch, sTo.ch)
  } else {
    var fromLine = getLine(doc, sFrom.line), toLine = getLine(doc, sTo.line)
    var singleVLine = visualLine(fromLine) == visualLine(toLine)
    var leftEnd = drawForLine(sFrom.line, sFrom.ch, singleVLine ? fromLine.text.length + 1 : null).end
    var rightStart = drawForLine(sTo.line, singleVLine ? 0 : null, sTo.ch).start
    if (singleVLine) {
      if (leftEnd.top < rightStart.top - 2) {
        add(leftEnd.right, leftEnd.top, null, leftEnd.bottom)
        add(leftSide, rightStart.top, rightStart.left, rightStart.bottom)
      } else {
        add(leftEnd.right, leftEnd.top, rightStart.left - leftEnd.right, leftEnd.bottom)
      }
    }
    if (leftEnd.bottom < rightStart.top)
      { add(leftSide, leftEnd.bottom, null, rightStart.top) }
  }

  output.appendChild(fragment)
}

// Cursor-blinking
function restartBlink(cm) {
  if (!cm.state.focused) { return }
  var display = cm.display
  clearInterval(display.blinker)
  var on = true
  display.cursorDiv.style.visibility = ""
  if (cm.options.cursorBlinkRate > 0)
    { display.blinker = setInterval(function () { return display.cursorDiv.style.visibility = (on = !on) ? "" : "hidden"; },
      cm.options.cursorBlinkRate) }
  else if (cm.options.cursorBlinkRate < 0)
    { display.cursorDiv.style.visibility = "hidden" }
}

function ensureFocus(cm) {
  if (!cm.state.focused) { cm.display.input.focus(); onFocus(cm) }
}

function delayBlurEvent(cm) {
  cm.state.delayingBlurEvent = true
  setTimeout(function () { if (cm.state.delayingBlurEvent) {
    cm.state.delayingBlurEvent = false
    onBlur(cm)
  } }, 100)
}

function onFocus(cm, e) {
  if (cm.state.delayingBlurEvent) { cm.state.delayingBlurEvent = false }

  if (cm.options.readOnly == "nocursor") { return }
  if (!cm.state.focused) {
    signal(cm, "focus", cm, e)
    cm.state.focused = true
    addClass(cm.display.wrapper, "CodeMirror-focused")
    // This test prevents this from firing when a context
    // menu is closed (since the input reset would kill the
    // select-all detection hack)
    if (!cm.curOp && cm.display.selForContextMenu != cm.doc.sel) {
      cm.display.input.reset()
      if (webkit) { setTimeout(function () { return cm.display.input.reset(true); }, 20) } // Issue #1730
    }
    cm.display.input.receivedFocus()
  }
  restartBlink(cm)
}
function onBlur(cm, e) {
  if (cm.state.delayingBlurEvent) { return }

  if (cm.state.focused) {
    signal(cm, "blur", cm, e)
    cm.state.focused = false
    rmClass(cm.display.wrapper, "CodeMirror-focused")
  }
  clearInterval(cm.display.blinker)
  setTimeout(function () { if (!cm.state.focused) { cm.display.shift = false } }, 150)
}

// Read the actual heights of the rendered lines, and update their
// stored heights to match.
function updateHeightsInViewport(cm) {
  var display = cm.display
  var prevBottom = display.lineDiv.offsetTop
  for (var i = 0; i < display.view.length; i++) {
    var cur = display.view[i], height = (void 0)
    if (cur.hidden) { continue }
    if (ie && ie_version < 8) {
      var bot = cur.node.offsetTop + cur.node.offsetHeight
      height = bot - prevBottom
      prevBottom = bot
    } else {
      var box = cur.node.getBoundingClientRect()
      height = box.bottom - box.top
    }
    var diff = cur.line.height - height
    if (height < 2) { height = textHeight(display) }
    if (diff > .005 || diff < -.005) {
      updateLineHeight(cur.line, height)
      updateWidgetHeight(cur.line)
      if (cur.rest) { for (var j = 0; j < cur.rest.length; j++)
        { updateWidgetHeight(cur.rest[j]) } }
    }
  }
}

// Read and store the height of line widgets associated with the
// given line.
function updateWidgetHeight(line) {
  if (line.widgets) { for (var i = 0; i < line.widgets.length; ++i) {
    var w = line.widgets[i], parent = w.node.parentNode
    if (parent) { w.height = parent.offsetHeight }
  } }
}

// Compute the lines that are visible in a given viewport (defaults
// the the current scroll position). viewport may contain top,
// height, and ensure (see op.scrollToPos) properties.
function visibleLines(display, doc, viewport) {
  var top = viewport && viewport.top != null ? Math.max(0, viewport.top) : display.scroller.scrollTop
  top = Math.floor(top - paddingTop(display))
  var bottom = viewport && viewport.bottom != null ? viewport.bottom : top + display.wrapper.clientHeight

  var from = lineAtHeight(doc, top), to = lineAtHeight(doc, bottom)
  // Ensure is a {from: {line, ch}, to: {line, ch}} object, and
  // forces those lines into the viewport (if possible).
  if (viewport && viewport.ensure) {
    var ensureFrom = viewport.ensure.from.line, ensureTo = viewport.ensure.to.line
    if (ensureFrom < from) {
      from = ensureFrom
      to = lineAtHeight(doc, heightAtLine(getLine(doc, ensureFrom)) + display.wrapper.clientHeight)
    } else if (Math.min(ensureTo, doc.lastLine()) >= to) {
      from = lineAtHeight(doc, heightAtLine(getLine(doc, ensureTo)) - display.wrapper.clientHeight)
      to = ensureTo
    }
  }
  return {from: from, to: Math.max(to, from + 1)}
}

// Re-align line numbers and gutter marks to compensate for
// horizontal scrolling.
function alignHorizontally(cm) {
  var display = cm.display, view = display.view
  if (!display.alignWidgets && (!display.gutters.firstChild || !cm.options.fixedGutter)) { return }
  var comp = compensateForHScroll(display) - display.scroller.scrollLeft + cm.doc.scrollLeft
  var gutterW = display.gutters.offsetWidth, left = comp + "px"
  for (var i = 0; i < view.length; i++) { if (!view[i].hidden) {
    if (cm.options.fixedGutter) {
      if (view[i].gutter)
        { view[i].gutter.style.left = left }
      if (view[i].gutterBackground)
        { view[i].gutterBackground.style.left = left }
    }
    var align = view[i].alignable
    if (align) { for (var j = 0; j < align.length; j++)
      { align[j].style.left = left } }
  } }
  if (cm.options.fixedGutter)
    { display.gutters.style.left = (comp + gutterW) + "px" }
}

// Used to ensure that the line number gutter is still the right
// size for the current document size. Returns true when an update
// is needed.
function maybeUpdateLineNumberWidth(cm) {
  if (!cm.options.lineNumbers) { return false }
  var doc = cm.doc, last = lineNumberFor(cm.options, doc.first + doc.size - 1), display = cm.display
  if (last.length != display.lineNumChars) {
    var test = display.measure.appendChild(elt("div", [elt("div", last)],
                                               "CodeMirror-linenumber CodeMirror-gutter-elt"))
    var innerW = test.firstChild.offsetWidth, padding = test.offsetWidth - innerW
    display.lineGutter.style.width = ""
    display.lineNumInnerWidth = Math.max(innerW, display.lineGutter.offsetWidth - padding) + 1
    display.lineNumWidth = display.lineNumInnerWidth + padding
    display.lineNumChars = display.lineNumInnerWidth ? last.length : -1
    display.lineGutter.style.width = display.lineNumWidth + "px"
    updateGutterSpace(cm)
    return true
  }
  return false
}

// SCROLLING THINGS INTO VIEW

// If an editor sits on the top or bottom of the window, partially
// scrolled out of view, this ensures that the cursor is visible.
function maybeScrollWindow(cm, rect) {
  if (signalDOMEvent(cm, "scrollCursorIntoView")) { return }

  var display = cm.display, box = display.sizer.getBoundingClientRect(), doScroll = null
  if (rect.top + box.top < 0) { doScroll = true }
  else if (rect.bottom + box.top > (window.innerHeight || document.documentElement.clientHeight)) { doScroll = false }
  if (doScroll != null && !phantom) {
    var scrollNode = elt("div", "\u200b", null, ("position: absolute;\n                         top: " + (rect.top - display.viewOffset - paddingTop(cm.display)) + "px;\n                         height: " + (rect.bottom - rect.top + scrollGap(cm) + display.barHeight) + "px;\n                         left: " + (rect.left) + "px; width: " + (Math.max(2, rect.right - rect.left)) + "px;"))
    cm.display.lineSpace.appendChild(scrollNode)
    scrollNode.scrollIntoView(doScroll)
    cm.display.lineSpace.removeChild(scrollNode)
  }
}

// Scroll a given position into view (immediately), verifying that
// it actually became visible (as line heights are accurately
// measured, the position of something may 'drift' during drawing).
function scrollPosIntoView(cm, pos, end, margin) {
  if (margin == null) { margin = 0 }
  var rect
  if (!cm.options.lineWrapping && pos == end) {
    // Set pos and end to the cursor positions around the character pos sticks to
    // If pos.sticky == "before", that is around pos.ch - 1, otherwise around pos.ch
    // If pos == Pos(_, 0, "before"), pos and end are unchanged
    pos = pos.ch ? Pos(pos.line, pos.sticky == "before" ? pos.ch - 1 : pos.ch, "after") : pos
    end = pos.sticky == "before" ? Pos(pos.line, pos.ch + 1, "before") : pos
  }
  for (var limit = 0; limit < 5; limit++) {
    var changed = false
    var coords = cursorCoords(cm, pos)
    var endCoords = !end || end == pos ? coords : cursorCoords(cm, end)
    rect = {left: Math.min(coords.left, endCoords.left),
            top: Math.min(coords.top, endCoords.top) - margin,
            right: Math.max(coords.left, endCoords.left),
            bottom: Math.max(coords.bottom, endCoords.bottom) + margin}
    var scrollPos = calculateScrollPos(cm, rect)
    var startTop = cm.doc.scrollTop, startLeft = cm.doc.scrollLeft
    if (scrollPos.scrollTop != null) {
      updateScrollTop(cm, scrollPos.scrollTop)
      if (Math.abs(cm.doc.scrollTop - startTop) > 1) { changed = true }
    }
    if (scrollPos.scrollLeft != null) {
      setScrollLeft(cm, scrollPos.scrollLeft)
      if (Math.abs(cm.doc.scrollLeft - startLeft) > 1) { changed = true }
    }
    if (!changed) { break }
  }
  return rect
}

// Scroll a given set of coordinates into view (immediately).
function scrollIntoView(cm, rect) {
  var scrollPos = calculateScrollPos(cm, rect)
  if (scrollPos.scrollTop != null) { updateScrollTop(cm, scrollPos.scrollTop) }
  if (scrollPos.scrollLeft != null) { setScrollLeft(cm, scrollPos.scrollLeft) }
}

// Calculate a new scroll position needed to scroll the given
// rectangle into view. Returns an object with scrollTop and
// scrollLeft properties. When these are undefined, the
// vertical/horizontal position does not need to be adjusted.
function calculateScrollPos(cm, rect) {
  var display = cm.display, snapMargin = textHeight(cm.display)
  if (rect.top < 0) { rect.top = 0 }
  var screentop = cm.curOp && cm.curOp.scrollTop != null ? cm.curOp.scrollTop : display.scroller.scrollTop
  var screen = displayHeight(cm), result = {}
  if (rect.bottom - rect.top > screen) { rect.bottom = rect.top + screen }
  var docBottom = cm.doc.height + paddingVert(display)
  var atTop = rect.top < snapMargin, atBottom = rect.bottom > docBottom - snapMargin
  if (rect.top < screentop) {
    result.scrollTop = atTop ? 0 : rect.top
  } else if (rect.bottom > screentop + screen) {
    var newTop = Math.min(rect.top, (atBottom ? docBottom : rect.bottom) - screen)
    if (newTop != screentop) { result.scrollTop = newTop }
  }

  var screenleft = cm.curOp && cm.curOp.scrollLeft != null ? cm.curOp.scrollLeft : display.scroller.scrollLeft
  var screenw = displayWidth(cm) - (cm.options.fixedGutter ? display.gutters.offsetWidth : 0)
  var tooWide = rect.right - rect.left > screenw
  if (tooWide) { rect.right = rect.left + screenw }
  if (rect.left < 10)
    { result.scrollLeft = 0 }
  else if (rect.left < screenleft)
    { result.scrollLeft = Math.max(0, rect.left - (tooWide ? 0 : 10)) }
  else if (rect.right > screenw + screenleft - 3)
    { result.scrollLeft = rect.right + (tooWide ? 0 : 10) - screenw }
  return result
}

// Store a relative adjustment to the scroll position in the current
// operation (to be applied when the operation finishes).
function addToScrollTop(cm, top) {
  if (top == null) { return }
  resolveScrollToPos(cm)
  cm.curOp.scrollTop = (cm.curOp.scrollTop == null ? cm.doc.scrollTop : cm.curOp.scrollTop) + top
}

// Make sure that at the end of the operation the current cursor is
// shown.
function ensureCursorVisible(cm) {
  resolveScrollToPos(cm)
  var cur = cm.getCursor()
  cm.curOp.scrollToPos = {from: cur, to: cur, margin: cm.options.cursorScrollMargin}
}

function scrollToCoords(cm, x, y) {
  if (x != null || y != null) { resolveScrollToPos(cm) }
  if (x != null) { cm.curOp.scrollLeft = x }
  if (y != null) { cm.curOp.scrollTop = y }
}

function scrollToRange(cm, range) {
  resolveScrollToPos(cm)
  cm.curOp.scrollToPos = range
}

// When an operation has its scrollToPos property set, and another
// scroll action is applied before the end of the operation, this
// 'simulates' scrolling that position into view in a cheap way, so
// that the effect of intermediate scroll commands is not ignored.
function resolveScrollToPos(cm) {
  var range = cm.curOp.scrollToPos
  if (range) {
    cm.curOp.scrollToPos = null
    var from = estimateCoords(cm, range.from), to = estimateCoords(cm, range.to)
    scrollToCoordsRange(cm, from, to, range.margin)
  }
}

function scrollToCoordsRange(cm, from, to, margin) {
  var sPos = calculateScrollPos(cm, {
    left: Math.min(from.left, to.left),
    top: Math.min(from.top, to.top) - margin,
    right: Math.max(from.right, to.right),
    bottom: Math.max(from.bottom, to.bottom) + margin
  })
  scrollToCoords(cm, sPos.scrollLeft, sPos.scrollTop)
}

// Sync the scrollable area and scrollbars, ensure the viewport
// covers the visible area.
function updateScrollTop(cm, val) {
  if (Math.abs(cm.doc.scrollTop - val) < 2) { return }
  if (!gecko) { updateDisplaySimple(cm, {top: val}) }
  setScrollTop(cm, val, true)
  if (gecko) { updateDisplaySimple(cm) }
  startWorker(cm, 100)
}

function setScrollTop(cm, val, forceScroll) {
  val = Math.min(cm.display.scroller.scrollHeight - cm.display.scroller.clientHeight, val)
  if (cm.display.scroller.scrollTop == val && !forceScroll) { return }
  cm.doc.scrollTop = val
  cm.display.scrollbars.setScrollTop(val)
  if (cm.display.scroller.scrollTop != val) { cm.display.scroller.scrollTop = val }
}

// Sync scroller and scrollbar, ensure the gutter elements are
// aligned.
function setScrollLeft(cm, val, isScroller, forceScroll) {
  val = Math.min(val, cm.display.scroller.scrollWidth - cm.display.scroller.clientWidth)
  if ((isScroller ? val == cm.doc.scrollLeft : Math.abs(cm.doc.scrollLeft - val) < 2) && !forceScroll) { return }
  cm.doc.scrollLeft = val
  alignHorizontally(cm)
  if (cm.display.scroller.scrollLeft != val) { cm.display.scroller.scrollLeft = val }
  cm.display.scrollbars.setScrollLeft(val)
}

// SCROLLBARS

// Prepare DOM reads needed to update the scrollbars. Done in one
// shot to minimize update/measure roundtrips.
function measureForScrollbars(cm) {
  var d = cm.display, gutterW = d.gutters.offsetWidth
  var docH = Math.round(cm.doc.height + paddingVert(cm.display))
  return {
    clientHeight: d.scroller.clientHeight,
    viewHeight: d.wrapper.clientHeight,
    scrollWidth: d.scroller.scrollWidth, clientWidth: d.scroller.clientWidth,
    viewWidth: d.wrapper.clientWidth,
    barLeft: cm.options.fixedGutter ? gutterW : 0,
    docHeight: docH,
    scrollHeight: docH + scrollGap(cm) + d.barHeight,
    nativeBarWidth: d.nativeBarWidth,
    gutterWidth: gutterW
  }
}

var NativeScrollbars = function(place, scroll, cm) {
  this.cm = cm
  var vert = this.vert = elt("div", [elt("div", null, null, "min-width: 1px")], "CodeMirror-vscrollbar")
  var horiz = this.horiz = elt("div", [elt("div", null, null, "height: 100%; min-height: 1px")], "CodeMirror-hscrollbar")
  vert.tabIndex = horiz.tabIndex = -1
  place(vert); place(horiz)

  on(vert, "scroll", function () {
    if (vert.clientHeight) { scroll(vert.scrollTop, "vertical") }
  })
  on(horiz, "scroll", function () {
    if (horiz.clientWidth) { scroll(horiz.scrollLeft, "horizontal") }
  })

  this.checkedZeroWidth = false
  // Need to set a minimum width to see the scrollbar on IE7 (but must not set it on IE8).
  if (ie && ie_version < 8) { this.horiz.style.minHeight = this.vert.style.minWidth = "18px" }
};

NativeScrollbars.prototype.update = function (measure) {
  var needsH = measure.scrollWidth > measure.clientWidth + 1
  var needsV = measure.scrollHeight > measure.clientHeight + 1
  var sWidth = measure.nativeBarWidth

  if (needsV) {
    this.vert.style.display = "block"
    this.vert.style.bottom = needsH ? sWidth + "px" : "0"
    var totalHeight = measure.viewHeight - (needsH ? sWidth : 0)
    // A bug in IE8 can cause this value to be negative, so guard it.
    this.vert.firstChild.style.height =
      Math.max(0, measure.scrollHeight - measure.clientHeight + totalHeight) + "px"
  } else {
    this.vert.style.display = ""
    this.vert.firstChild.style.height = "0"
  }

  if (needsH) {
    this.horiz.style.display = "block"
    this.horiz.style.right = needsV ? sWidth + "px" : "0"
    this.horiz.style.left = measure.barLeft + "px"
    var totalWidth = measure.viewWidth - measure.barLeft - (needsV ? sWidth : 0)
    this.horiz.firstChild.style.width =
      Math.max(0, measure.scrollWidth - measure.clientWidth + totalWidth) + "px"
  } else {
    this.horiz.style.display = ""
    this.horiz.firstChild.style.width = "0"
  }

  if (!this.checkedZeroWidth && measure.clientHeight > 0) {
    if (sWidth == 0) { this.zeroWidthHack() }
    this.checkedZeroWidth = true
  }

  return {right: needsV ? sWidth : 0, bottom: needsH ? sWidth : 0}
};

NativeScrollbars.prototype.setScrollLeft = function (pos) {
  if (this.horiz.scrollLeft != pos) { this.horiz.scrollLeft = pos }
  if (this.disableHoriz) { this.enableZeroWidthBar(this.horiz, this.disableHoriz, "horiz") }
};

NativeScrollbars.prototype.setScrollTop = function (pos) {
  if (this.vert.scrollTop != pos) { this.vert.scrollTop = pos }
  if (this.disableVert) { this.enableZeroWidthBar(this.vert, this.disableVert, "vert") }
};

NativeScrollbars.prototype.zeroWidthHack = function () {
  var w = mac && !mac_geMountainLion ? "12px" : "18px"
  this.horiz.style.height = this.vert.style.width = w
  this.horiz.style.pointerEvents = this.vert.style.pointerEvents = "none"
  this.disableHoriz = new Delayed
  this.disableVert = new Delayed
};

NativeScrollbars.prototype.enableZeroWidthBar = function (bar, delay, type) {
  bar.style.pointerEvents = "auto"
  function maybeDisable() {
    // To find out whether the scrollbar is still visible, we
    // check whether the element under the pixel in the bottom
    // right corner of the scrollbar box is the scrollbar box
    // itself (when the bar is still visible) or its filler child
    // (when the bar is hidden). If it is still visible, we keep
    // it enabled, if it's hidden, we disable pointer events.
    var box = bar.getBoundingClientRect()
    var elt = type == "vert" ? document.elementFromPoint(box.right - 1, (box.top + box.bottom) / 2)
        : document.elementFromPoint((box.right + box.left) / 2, box.bottom - 1)
    if (elt != bar) { bar.style.pointerEvents = "none" }
    else { delay.set(1000, maybeDisable) }
  }
  delay.set(1000, maybeDisable)
};

NativeScrollbars.prototype.clear = function () {
  var parent = this.horiz.parentNode
  parent.removeChild(this.horiz)
  parent.removeChild(this.vert)
};

var NullScrollbars = function () {};

NullScrollbars.prototype.update = function () { return {bottom: 0, right: 0} };
NullScrollbars.prototype.setScrollLeft = function () {};
NullScrollbars.prototype.setScrollTop = function () {};
NullScrollbars.prototype.clear = function () {};

function updateScrollbars(cm, measure) {
  if (!measure) { measure = measureForScrollbars(cm) }
  var startWidth = cm.display.barWidth, startHeight = cm.display.barHeight
  updateScrollbarsInner(cm, measure)
  for (var i = 0; i < 4 && startWidth != cm.display.barWidth || startHeight != cm.display.barHeight; i++) {
    if (startWidth != cm.display.barWidth && cm.options.lineWrapping)
      { updateHeightsInViewport(cm) }
    updateScrollbarsInner(cm, measureForScrollbars(cm))
    startWidth = cm.display.barWidth; startHeight = cm.display.barHeight
  }
}

// Re-synchronize the fake scrollbars with the actual size of the
// content.
function updateScrollbarsInner(cm, measure) {
  var d = cm.display
  var sizes = d.scrollbars.update(measure)

  d.sizer.style.paddingRight = (d.barWidth = sizes.right) + "px"
  d.sizer.style.paddingBottom = (d.barHeight = sizes.bottom) + "px"
  d.heightForcer.style.borderBottom = sizes.bottom + "px solid transparent"

  if (sizes.right && sizes.bottom) {
    d.scrollbarFiller.style.display = "block"
    d.scrollbarFiller.style.height = sizes.bottom + "px"
    d.scrollbarFiller.style.width = sizes.right + "px"
  } else { d.scrollbarFiller.style.display = "" }
  if (sizes.bottom && cm.options.coverGutterNextToScrollbar && cm.options.fixedGutter) {
    d.gutterFiller.style.display = "block"
    d.gutterFiller.style.height = sizes.bottom + "px"
    d.gutterFiller.style.width = measure.gutterWidth + "px"
  } else { d.gutterFiller.style.display = "" }
}

var scrollbarModel = {"native": NativeScrollbars, "null": NullScrollbars}

function initScrollbars(cm) {
  if (cm.display.scrollbars) {
    cm.display.scrollbars.clear()
    if (cm.display.scrollbars.addClass)
      { rmClass(cm.display.wrapper, cm.display.scrollbars.addClass) }
  }

  cm.display.scrollbars = new scrollbarModel[cm.options.scrollbarStyle](function (node) {
    cm.display.wrapper.insertBefore(node, cm.display.scrollbarFiller)
    // Prevent clicks in the scrollbars from killing focus
    on(node, "mousedown", function () {
      if (cm.state.focused) { setTimeout(function () { return cm.display.input.focus(); }, 0) }
    })
    node.setAttribute("cm-not-content", "true")
  }, function (pos, axis) {
    if (axis == "horizontal") { setScrollLeft(cm, pos) }
    else { updateScrollTop(cm, pos) }
  }, cm)
  if (cm.display.scrollbars.addClass)
    { addClass(cm.display.wrapper, cm.display.scrollbars.addClass) }
}

// Operations are used to wrap a series of changes to the editor
// state in such a way that each change won't have to update the
// cursor and display (which would be awkward, slow, and
// error-prone). Instead, display updates are batched and then all
// combined and executed at once.

var nextOpId = 0
// Start a new operation.
function startOperation(cm) {
  cm.curOp = {
    cm: cm,
    viewChanged: false,      // Flag that indicates that lines might need to be redrawn
    startHeight: cm.doc.height, // Used to detect need to update scrollbar
    forceUpdate: false,      // Used to force a redraw
    updateInput: null,       // Whether to reset the input textarea
    typing: false,           // Whether this reset should be careful to leave existing text (for compositing)
    changeObjs: null,        // Accumulated changes, for firing change events
    cursorActivityHandlers: null, // Set of handlers to fire cursorActivity on
    cursorActivityCalled: 0, // Tracks which cursorActivity handlers have been called already
    selectionChanged: false, // Whether the selection needs to be redrawn
    updateMaxLine: false,    // Set when the widest line needs to be determined anew
    scrollLeft: null, scrollTop: null, // Intermediate scroll position, not pushed to DOM yet
    scrollToPos: null,       // Used to scroll to a specific position
    focus: false,
    id: ++nextOpId           // Unique ID
  }
  pushOperation(cm.curOp)
}

// Finish an operation, updating the display and signalling delayed events
function endOperation(cm) {
  var op = cm.curOp
  finishOperation(op, function (group) {
    for (var i = 0; i < group.ops.length; i++)
      { group.ops[i].cm.curOp = null }
    endOperations(group)
  })
}

// The DOM updates done when an operation finishes are batched so
// that the minimum number of relayouts are required.
function endOperations(group) {
  var ops = group.ops
  for (var i = 0; i < ops.length; i++) // Read DOM
    { endOperation_R1(ops[i]) }
  for (var i$1 = 0; i$1 < ops.length; i$1++) // Write DOM (maybe)
    { endOperation_W1(ops[i$1]) }
  for (var i$2 = 0; i$2 < ops.length; i$2++) // Read DOM
    { endOperation_R2(ops[i$2]) }
  for (var i$3 = 0; i$3 < ops.length; i$3++) // Write DOM (maybe)
    { endOperation_W2(ops[i$3]) }
  for (var i$4 = 0; i$4 < ops.length; i$4++) // Read DOM
    { endOperation_finish(ops[i$4]) }
}

function endOperation_R1(op) {
  var cm = op.cm, display = cm.display
  maybeClipScrollbars(cm)
  if (op.updateMaxLine) { findMaxLine(cm) }

  op.mustUpdate = op.viewChanged || op.forceUpdate || op.scrollTop != null ||
    op.scrollToPos && (op.scrollToPos.from.line < display.viewFrom ||
                       op.scrollToPos.to.line >= display.viewTo) ||
    display.maxLineChanged && cm.options.lineWrapping
  op.update = op.mustUpdate &&
    new DisplayUpdate(cm, op.mustUpdate && {top: op.scrollTop, ensure: op.scrollToPos}, op.forceUpdate)
}

function endOperation_W1(op) {
  op.updatedDisplay = op.mustUpdate && updateDisplayIfNeeded(op.cm, op.update)
}

function endOperation_R2(op) {
  var cm = op.cm, display = cm.display
  if (op.updatedDisplay) { updateHeightsInViewport(cm) }

  op.barMeasure = measureForScrollbars(cm)

  // If the max line changed since it was last measured, measure it,
  // and ensure the document's width matches it.
  // updateDisplay_W2 will use these properties to do the actual resizing
  if (display.maxLineChanged && !cm.options.lineWrapping) {
    op.adjustWidthTo = measureChar(cm, display.maxLine, display.maxLine.text.length).left + 3
    cm.display.sizerWidth = op.adjustWidthTo
    op.barMeasure.scrollWidth =
      Math.max(display.scroller.clientWidth, display.sizer.offsetLeft + op.adjustWidthTo + scrollGap(cm) + cm.display.barWidth)
    op.maxScrollLeft = Math.max(0, display.sizer.offsetLeft + op.adjustWidthTo - displayWidth(cm))
  }

  if (op.updatedDisplay || op.selectionChanged)
    { op.preparedSelection = display.input.prepareSelection() }
}

function endOperation_W2(op) {
  var cm = op.cm

  if (op.adjustWidthTo != null) {
    cm.display.sizer.style.minWidth = op.adjustWidthTo + "px"
    if (op.maxScrollLeft < cm.doc.scrollLeft)
      { setScrollLeft(cm, Math.min(cm.display.scroller.scrollLeft, op.maxScrollLeft), true) }
    cm.display.maxLineChanged = false
  }

  var takeFocus = op.focus && op.focus == activeElt()
  if (op.preparedSelection)
    { cm.display.input.showSelection(op.preparedSelection, takeFocus) }
  if (op.updatedDisplay || op.startHeight != cm.doc.height)
    { updateScrollbars(cm, op.barMeasure) }
  if (op.updatedDisplay)
    { setDocumentHeight(cm, op.barMeasure) }

  if (op.selectionChanged) { restartBlink(cm) }

  if (cm.state.focused && op.updateInput)
    { cm.display.input.reset(op.typing) }
  if (takeFocus) { ensureFocus(op.cm) }
}

function endOperation_finish(op) {
  var cm = op.cm, display = cm.display, doc = cm.doc

  if (op.updatedDisplay) { postUpdateDisplay(cm, op.update) }

  // Abort mouse wheel delta measurement, when scrolling explicitly
  if (display.wheelStartX != null && (op.scrollTop != null || op.scrollLeft != null || op.scrollToPos))
    { display.wheelStartX = display.wheelStartY = null }

  // Propagate the scroll position to the actual DOM scroller
  if (op.scrollTop != null) { setScrollTop(cm, op.scrollTop, op.forceScroll) }

  if (op.scrollLeft != null) { setScrollLeft(cm, op.scrollLeft, true, true) }
  // If we need to scroll a specific position into view, do so.
  if (op.scrollToPos) {
    var rect = scrollPosIntoView(cm, clipPos(doc, op.scrollToPos.from),
                                 clipPos(doc, op.scrollToPos.to), op.scrollToPos.margin)
    maybeScrollWindow(cm, rect)
  }

  // Fire events for markers that are hidden/unidden by editing or
  // undoing
  var hidden = op.maybeHiddenMarkers, unhidden = op.maybeUnhiddenMarkers
  if (hidden) { for (var i = 0; i < hidden.length; ++i)
    { if (!hidden[i].lines.length) { signal(hidden[i], "hide") } } }
  if (unhidden) { for (var i$1 = 0; i$1 < unhidden.length; ++i$1)
    { if (unhidden[i$1].lines.length) { signal(unhidden[i$1], "unhide") } } }

  if (display.wrapper.offsetHeight)
    { doc.scrollTop = cm.display.scroller.scrollTop }

  // Fire change events, and delayed event handlers
  if (op.changeObjs)
    { signal(cm, "changes", cm, op.changeObjs) }
  if (op.update)
    { op.update.finish() }
}

// Run the given function in an operation
function runInOp(cm, f) {
  if (cm.curOp) { return f() }
  startOperation(cm)
  try { return f() }
  finally { endOperation(cm) }
}
// Wraps a function in an operation. Returns the wrapped function.
function operation(cm, f) {
  return function() {
    if (cm.curOp) { return f.apply(cm, arguments) }
    startOperation(cm)
    try { return f.apply(cm, arguments) }
    finally { endOperation(cm) }
  }
}
// Used to add methods to editor and doc instances, wrapping them in
// operations.
function methodOp(f) {
  return function() {
    if (this.curOp) { return f.apply(this, arguments) }
    startOperation(this)
    try { return f.apply(this, arguments) }
    finally { endOperation(this) }
  }
}
function docMethodOp(f) {
  return function() {
    var cm = this.cm
    if (!cm || cm.curOp) { return f.apply(this, arguments) }
    startOperation(cm)
    try { return f.apply(this, arguments) }
    finally { endOperation(cm) }
  }
}

// Updates the display.view data structure for a given change to the
// document. From and to are in pre-change coordinates. Lendiff is
// the amount of lines added or subtracted by the change. This is
// used for changes that span multiple lines, or change the way
// lines are divided into visual lines. regLineChange (below)
// registers single-line changes.
function regChange(cm, from, to, lendiff) {
  if (from == null) { from = cm.doc.first }
  if (to == null) { to = cm.doc.first + cm.doc.size }
  if (!lendiff) { lendiff = 0 }

  var display = cm.display
  if (lendiff && to < display.viewTo &&
      (display.updateLineNumbers == null || display.updateLineNumbers > from))
    { display.updateLineNumbers = from }

  cm.curOp.viewChanged = true

  if (from >= display.viewTo) { // Change after
    if (sawCollapsedSpans && visualLineNo(cm.doc, from) < display.viewTo)
      { resetView(cm) }
  } else if (to <= display.viewFrom) { // Change before
    if (sawCollapsedSpans && visualLineEndNo(cm.doc, to + lendiff) > display.viewFrom) {
      resetView(cm)
    } else {
      display.viewFrom += lendiff
      display.viewTo += lendiff
    }
  } else if (from <= display.viewFrom && to >= display.viewTo) { // Full overlap
    resetView(cm)
  } else if (from <= display.viewFrom) { // Top overlap
    var cut = viewCuttingPoint(cm, to, to + lendiff, 1)
    if (cut) {
      display.view = display.view.slice(cut.index)
      display.viewFrom = cut.lineN
      display.viewTo += lendiff
    } else {
      resetView(cm)
    }
  } else if (to >= display.viewTo) { // Bottom overlap
    var cut$1 = viewCuttingPoint(cm, from, from, -1)
    if (cut$1) {
      display.view = display.view.slice(0, cut$1.index)
      display.viewTo = cut$1.lineN
    } else {
      resetView(cm)
    }
  } else { // Gap in the middle
    var cutTop = viewCuttingPoint(cm, from, from, -1)
    var cutBot = viewCuttingPoint(cm, to, to + lendiff, 1)
    if (cutTop && cutBot) {
      display.view = display.view.slice(0, cutTop.index)
        .concat(buildViewArray(cm, cutTop.lineN, cutBot.lineN))
        .concat(display.view.slice(cutBot.index))
      display.viewTo += lendiff
    } else {
      resetView(cm)
    }
  }

  var ext = display.externalMeasured
  if (ext) {
    if (to < ext.lineN)
      { ext.lineN += lendiff }
    else if (from < ext.lineN + ext.size)
      { display.externalMeasured = null }
  }
}

// Register a change to a single line. Type must be one of "text",
// "gutter", "class", "widget"
function regLineChange(cm, line, type) {
  cm.curOp.viewChanged = true
  var display = cm.display, ext = cm.display.externalMeasured
  if (ext && line >= ext.lineN && line < ext.lineN + ext.size)
    { display.externalMeasured = null }

  if (line < display.viewFrom || line >= display.viewTo) { return }
  var lineView = display.view[findViewIndex(cm, line)]
  if (lineView.node == null) { return }
  var arr = lineView.changes || (lineView.changes = [])
  if (indexOf(arr, type) == -1) { arr.push(type) }
}

// Clear the view.
function resetView(cm) {
  cm.display.viewFrom = cm.display.viewTo = cm.doc.first
  cm.display.view = []
  cm.display.viewOffset = 0
}

function viewCuttingPoint(cm, oldN, newN, dir) {
  var index = findViewIndex(cm, oldN), diff, view = cm.display.view
  if (!sawCollapsedSpans || newN == cm.doc.first + cm.doc.size)
    { return {index: index, lineN: newN} }
  var n = cm.display.viewFrom
  for (var i = 0; i < index; i++)
    { n += view[i].size }
  if (n != oldN) {
    if (dir > 0) {
      if (index == view.length - 1) { return null }
      diff = (n + view[index].size) - oldN
      index++
    } else {
      diff = n - oldN
    }
    oldN += diff; newN += diff
  }
  while (visualLineNo(cm.doc, newN) != newN) {
    if (index == (dir < 0 ? 0 : view.length - 1)) { return null }
    newN += dir * view[index - (dir < 0 ? 1 : 0)].size
    index += dir
  }
  return {index: index, lineN: newN}
}

// Force the view to cover a given range, adding empty view element
// or clipping off existing ones as needed.
function adjustView(cm, from, to) {
  var display = cm.display, view = display.view
  if (view.length == 0 || from >= display.viewTo || to <= display.viewFrom) {
    display.view = buildViewArray(cm, from, to)
    display.viewFrom = from
  } else {
    if (display.viewFrom > from)
      { display.view = buildViewArray(cm, from, display.viewFrom).concat(display.view) }
    else if (display.viewFrom < from)
      { display.view = display.view.slice(findViewIndex(cm, from)) }
    display.viewFrom = from
    if (display.viewTo < to)
      { display.view = display.view.concat(buildViewArray(cm, display.viewTo, to)) }
    else if (display.viewTo > to)
      { display.view = display.view.slice(0, findViewIndex(cm, to)) }
  }
  display.viewTo = to
}

// Count the number of lines in the view whose DOM representation is
// out of date (or nonexistent).
function countDirtyView(cm) {
  var view = cm.display.view, dirty = 0
  for (var i = 0; i < view.length; i++) {
    var lineView = view[i]
    if (!lineView.hidden && (!lineView.node || lineView.changes)) { ++dirty }
  }
  return dirty
}

// HIGHLIGHT WORKER

function startWorker(cm, time) {
  if (cm.doc.highlightFrontier < cm.display.viewTo)
    { cm.state.highlight.set(time, bind(highlightWorker, cm)) }
}

function highlightWorker(cm) {
  var doc = cm.doc
  if (doc.highlightFrontier >= cm.display.viewTo) { return }
  var end = +new Date + cm.options.workTime
  var context = getContextBefore(cm, doc.highlightFrontier)
  var changedLines = []

  doc.iter(context.line, Math.min(doc.first + doc.size, cm.display.viewTo + 500), function (line) {
    if (context.line >= cm.display.viewFrom) { // Visible
      var oldStyles = line.styles
      var resetState = line.text.length > cm.options.maxHighlightLength ? copyState(doc.mode, context.state) : null
      var highlighted = highlightLine(cm, line, context, true)
      if (resetState) { context.state = resetState }
      line.styles = highlighted.styles
      var oldCls = line.styleClasses, newCls = highlighted.classes
      if (newCls) { line.styleClasses = newCls }
      else if (oldCls) { line.styleClasses = null }
      var ischange = !oldStyles || oldStyles.length != line.styles.length ||
        oldCls != newCls && (!oldCls || !newCls || oldCls.bgClass != newCls.bgClass || oldCls.textClass != newCls.textClass)
      for (var i = 0; !ischange && i < oldStyles.length; ++i) { ischange = oldStyles[i] != line.styles[i] }
      if (ischange) { changedLines.push(context.line) }
      line.stateAfter = context.save()
      context.nextLine()
    } else {
      if (line.text.length <= cm.options.maxHighlightLength)
        { processLine(cm, line.text, context) }
      line.stateAfter = context.line % 5 == 0 ? context.save() : null
      context.nextLine()
    }
    if (+new Date > end) {
      startWorker(cm, cm.options.workDelay)
      return true
    }
  })
  doc.highlightFrontier = context.line
  doc.modeFrontier = Math.max(doc.modeFrontier, context.line)
  if (changedLines.length) { runInOp(cm, function () {
    for (var i = 0; i < changedLines.length; i++)
      { regLineChange(cm, changedLines[i], "text") }
  }) }
}

// DISPLAY DRAWING

var DisplayUpdate = function(cm, viewport, force) {
  var display = cm.display

  this.viewport = viewport
  // Store some values that we'll need later (but don't want to force a relayout for)
  this.visible = visibleLines(display, cm.doc, viewport)
  this.editorIsHidden = !display.wrapper.offsetWidth
  this.wrapperHeight = display.wrapper.clientHeight
  this.wrapperWidth = display.wrapper.clientWidth
  this.oldDisplayWidth = displayWidth(cm)
  this.force = force
  this.dims = getDimensions(cm)
  this.events = []
};

DisplayUpdate.prototype.signal = function (emitter, type) {
  if (hasHandler(emitter, type))
    { this.events.push(arguments) }
};
DisplayUpdate.prototype.finish = function () {
    var this$1 = this;

  for (var i = 0; i < this.events.length; i++)
    { signal.apply(null, this$1.events[i]) }
};

function maybeClipScrollbars(cm) {
  var display = cm.display
  if (!display.scrollbarsClipped && display.scroller.offsetWidth) {
    display.nativeBarWidth = display.scroller.offsetWidth - display.scroller.clientWidth
    display.heightForcer.style.height = scrollGap(cm) + "px"
    display.sizer.style.marginBottom = -display.nativeBarWidth + "px"
    display.sizer.style.borderRightWidth = scrollGap(cm) + "px"
    display.scrollbarsClipped = true
  }
}

function selectionSnapshot(cm) {
  if (cm.hasFocus()) { return null }
  var active = activeElt()
  if (!active || !contains(cm.display.lineDiv, active)) { return null }
  var result = {activeElt: active}
  if (window.getSelection) {
    var sel = window.getSelection()
    if (sel.anchorNode && sel.extend && contains(cm.display.lineDiv, sel.anchorNode)) {
      result.anchorNode = sel.anchorNode
      result.anchorOffset = sel.anchorOffset
      result.focusNode = sel.focusNode
      result.focusOffset = sel.focusOffset
    }
  }
  return result
}

function restoreSelection(snapshot) {
  if (!snapshot || !snapshot.activeElt || snapshot.activeElt == activeElt()) { return }
  snapshot.activeElt.focus()
  if (snapshot.anchorNode && contains(document.body, snapshot.anchorNode) && contains(document.body, snapshot.focusNode)) {
    var sel = window.getSelection(), range = document.createRange()
    range.setEnd(snapshot.anchorNode, snapshot.anchorOffset)
    range.collapse(false)
    sel.removeAllRanges()
    sel.addRange(range)
    sel.extend(snapshot.focusNode, snapshot.focusOffset)
  }
}

// Does the actual updating of the line display. Bails out
// (returning false) when there is nothing to be done and forced is
// false.
function updateDisplayIfNeeded(cm, update) {
  var display = cm.display, doc = cm.doc

  if (update.editorIsHidden) {
    resetView(cm)
    return false
  }

  // Bail out if the visible area is already rendered and nothing changed.
  if (!update.force &&
      update.visible.from >= display.viewFrom && update.visible.to <= display.viewTo &&
      (display.updateLineNumbers == null || display.updateLineNumbers >= display.viewTo) &&
      display.renderedView == display.view && countDirtyView(cm) == 0)
    { return false }

  if (maybeUpdateLineNumberWidth(cm)) {
    resetView(cm)
    update.dims = getDimensions(cm)
  }

  // Compute a suitable new viewport (from & to)
  var end = doc.first + doc.size
  var from = Math.max(update.visible.from - cm.options.viewportMargin, doc.first)
  var to = Math.min(end, update.visible.to + cm.options.viewportMargin)
  if (display.viewFrom < from && from - display.viewFrom < 20) { from = Math.max(doc.first, display.viewFrom) }
  if (display.viewTo > to && display.viewTo - to < 20) { to = Math.min(end, display.viewTo) }
  if (sawCollapsedSpans) {
    from = visualLineNo(cm.doc, from)
    to = visualLineEndNo(cm.doc, to)
  }

  var different = from != display.viewFrom || to != display.viewTo ||
    display.lastWrapHeight != update.wrapperHeight || display.lastWrapWidth != update.wrapperWidth
  adjustView(cm, from, to)

  display.viewOffset = heightAtLine(getLine(cm.doc, display.viewFrom))
  // Position the mover div to align with the current scroll position
  cm.display.mover.style.top = display.viewOffset + "px"

  var toUpdate = countDirtyView(cm)
  if (!different && toUpdate == 0 && !update.force && display.renderedView == display.view &&
      (display.updateLineNumbers == null || display.updateLineNumbers >= display.viewTo))
    { return false }

  // For big changes, we hide the enclosing element during the
  // update, since that speeds up the operations on most browsers.
  var selSnapshot = selectionSnapshot(cm)
  if (toUpdate > 4) { display.lineDiv.style.display = "none" }
  patchDisplay(cm, display.updateLineNumbers, update.dims)
  if (toUpdate > 4) { display.lineDiv.style.display = "" }
  display.renderedView = display.view
  // There might have been a widget with a focused element that got
  // hidden or updated, if so re-focus it.
  restoreSelection(selSnapshot)

  // Prevent selection and cursors from interfering with the scroll
  // width and height.
  removeChildren(display.cursorDiv)
  removeChildren(display.selectionDiv)
  display.gutters.style.height = display.sizer.style.minHeight = 0

  if (different) {
    display.lastWrapHeight = update.wrapperHeight
    display.lastWrapWidth = update.wrapperWidth
    startWorker(cm, 400)
  }

  display.updateLineNumbers = null

  return true
}

function postUpdateDisplay(cm, update) {
  var viewport = update.viewport

  for (var first = true;; first = false) {
    if (!first || !cm.options.lineWrapping || update.oldDisplayWidth == displayWidth(cm)) {
      // Clip forced viewport to actual scrollable area.
      if (viewport && viewport.top != null)
        { viewport = {top: Math.min(cm.doc.height + paddingVert(cm.display) - displayHeight(cm), viewport.top)} }
      // Updated line heights might result in the drawn area not
      // actually covering the viewport. Keep looping until it does.
      update.visible = visibleLines(cm.display, cm.doc, viewport)
      if (update.visible.from >= cm.display.viewFrom && update.visible.to <= cm.display.viewTo)
        { break }
    }
    if (!updateDisplayIfNeeded(cm, update)) { break }
    updateHeightsInViewport(cm)
    var barMeasure = measureForScrollbars(cm)
    updateSelection(cm)
    updateScrollbars(cm, barMeasure)
    setDocumentHeight(cm, barMeasure)
    update.force = false
  }

  update.signal(cm, "update", cm)
  if (cm.display.viewFrom != cm.display.reportedViewFrom || cm.display.viewTo != cm.display.reportedViewTo) {
    update.signal(cm, "viewportChange", cm, cm.display.viewFrom, cm.display.viewTo)
    cm.display.reportedViewFrom = cm.display.viewFrom; cm.display.reportedViewTo = cm.display.viewTo
  }
}

function updateDisplaySimple(cm, viewport) {
  var update = new DisplayUpdate(cm, viewport)
  if (updateDisplayIfNeeded(cm, update)) {
    updateHeightsInViewport(cm)
    postUpdateDisplay(cm, update)
    var barMeasure = measureForScrollbars(cm)
    updateSelection(cm)
    updateScrollbars(cm, barMeasure)
    setDocumentHeight(cm, barMeasure)
    update.finish()
  }
}

// Sync the actual display DOM structure with display.view, removing
// nodes for lines that are no longer in view, and creating the ones
// that are not there yet, and updating the ones that are out of
// date.
function patchDisplay(cm, updateNumbersFrom, dims) {
  var display = cm.display, lineNumbers = cm.options.lineNumbers
  var container = display.lineDiv, cur = container.firstChild

  function rm(node) {
    var next = node.nextSibling
    // Works around a throw-scroll bug in OS X Webkit
    if (webkit && mac && cm.display.currentWheelTarget == node)
      { node.style.display = "none" }
    else
      { node.parentNode.removeChild(node) }
    return next
  }

  var view = display.view, lineN = display.viewFrom
  // Loop over the elements in the view, syncing cur (the DOM nodes
  // in display.lineDiv) with the view as we go.
  for (var i = 0; i < view.length; i++) {
    var lineView = view[i]
    if (lineView.hidden) {
    } else if (!lineView.node || lineView.node.parentNode != container) { // Not drawn yet
      var node = buildLineElement(cm, lineView, lineN, dims)
      container.insertBefore(node, cur)
    } else { // Already drawn
      while (cur != lineView.node) { cur = rm(cur) }
      var updateNumber = lineNumbers && updateNumbersFrom != null &&
        updateNumbersFrom <= lineN && lineView.lineNumber
      if (lineView.changes) {
        if (indexOf(lineView.changes, "gutter") > -1) { updateNumber = false }
        updateLineForChanges(cm, lineView, lineN, dims)
      }
      if (updateNumber) {
        removeChildren(lineView.lineNumber)
        lineView.lineNumber.appendChild(document.createTextNode(lineNumberFor(cm.options, lineN)))
      }
      cur = lineView.node.nextSibling
    }
    lineN += lineView.size
  }
  while (cur) { cur = rm(cur) }
}

function updateGutterSpace(cm) {
  var width = cm.display.gutters.offsetWidth
  cm.display.sizer.style.marginLeft = width + "px"
}

function setDocumentHeight(cm, measure) {
  cm.display.sizer.style.minHeight = measure.docHeight + "px"
  cm.display.heightForcer.style.top = measure.docHeight + "px"
  cm.display.gutters.style.height = (measure.docHeight + cm.display.barHeight + scrollGap(cm)) + "px"
}

// Rebuild the gutter elements, ensure the margin to the left of the
// code matches their width.
function updateGutters(cm) {
  var gutters = cm.display.gutters, specs = cm.options.gutters
  removeChildren(gutters)
  var i = 0
  for (; i < specs.length; ++i) {
    var gutterClass = specs[i]
    var gElt = gutters.appendChild(elt("div", null, "CodeMirror-gutter " + gutterClass))
    if (gutterClass == "CodeMirror-linenumbers") {
      cm.display.lineGutter = gElt
      gElt.style.width = (cm.display.lineNumWidth || 1) + "px"
    }
  }
  gutters.style.display = i ? "" : "none"
  updateGutterSpace(cm)
}

// Make sure the gutters options contains the element
// "CodeMirror-linenumbers" when the lineNumbers option is true.
function setGuttersForLineNumbers(options) {
  var found = indexOf(options.gutters, "CodeMirror-linenumbers")
  if (found == -1 && options.lineNumbers) {
    options.gutters = options.gutters.concat(["CodeMirror-linenumbers"])
  } else if (found > -1 && !options.lineNumbers) {
    options.gutters = options.gutters.slice(0)
    options.gutters.splice(found, 1)
  }
}

var wheelSamples = 0;
var wheelPixelsPerUnit = null;
// Fill in a browser-detected starting value on browsers where we
// know one. These don't have to be accurate -- the result of them
// being wrong would just be a slight flicker on the first wheel
// scroll (if it is large enough).
if (ie) { wheelPixelsPerUnit = -.53 }
else if (gecko) { wheelPixelsPerUnit = 15 }
else if (chrome) { wheelPixelsPerUnit = -.7 }
else if (safari) { wheelPixelsPerUnit = -1/3 }

function wheelEventDelta(e) {
  var dx = e.wheelDeltaX, dy = e.wheelDeltaY
  if (dx == null && e.detail && e.axis == e.HORIZONTAL_AXIS) { dx = e.detail }
  if (dy == null && e.detail && e.axis == e.VERTICAL_AXIS) { dy = e.detail }
  else if (dy == null) { dy = e.wheelDelta }
  return {x: dx, y: dy}
}
function wheelEventPixels(e) {
  var delta = wheelEventDelta(e)
  delta.x *= wheelPixelsPerUnit
  delta.y *= wheelPixelsPerUnit
  return delta
}

function onScrollWheel(cm, e) {
  var delta = wheelEventDelta(e), dx = delta.x, dy = delta.y

  var display = cm.display, scroll = display.scroller
  // Quit if there's nothing to scroll here
  var canScrollX = scroll.scrollWidth > scroll.clientWidth
  var canScrollY = scroll.scrollHeight > scroll.clientHeight
  if (!(dx && canScrollX || dy && canScrollY)) { return }

  // Webkit browsers on OS X abort momentum scrolls when the target
  // of the scroll event is removed from the scrollable element.
  // This hack (see related code in patchDisplay) makes sure the
  // element is kept around.
  if (dy && mac && webkit) {
    outer: for (var cur = e.target, view = display.view; cur != scroll; cur = cur.parentNode) {
      for (var i = 0; i < view.length; i++) {
        if (view[i].node == cur) {
          cm.display.currentWheelTarget = cur
          break outer
        }
      }
    }
  }

  // On some browsers, horizontal scrolling will cause redraws to
  // happen before the gutter has been realigned, causing it to
  // wriggle around in a most unseemly way. When we have an
  // estimated pixels/delta value, we just handle horizontal
  // scrolling entirely here. It'll be slightly off from native, but
  // better than glitching out.
  if (dx && !gecko && !presto && wheelPixelsPerUnit != null) {
    if (dy && canScrollY)
      { updateScrollTop(cm, Math.max(0, scroll.scrollTop + dy * wheelPixelsPerUnit)) }
    setScrollLeft(cm, Math.max(0, scroll.scrollLeft + dx * wheelPixelsPerUnit))
    // Only prevent default scrolling if vertical scrolling is
    // actually possible. Otherwise, it causes vertical scroll
    // jitter on OSX trackpads when deltaX is small and deltaY
    // is large (issue #3579)
    if (!dy || (dy && canScrollY))
      { e_preventDefault(e) }
    display.wheelStartX = null // Abort measurement, if in progress
    return
  }

  // 'Project' the visible viewport to cover the area that is being
  // scrolled into view (if we know enough to estimate it).
  if (dy && wheelPixelsPerUnit != null) {
    var pixels = dy * wheelPixelsPerUnit
    var top = cm.doc.scrollTop, bot = top + display.wrapper.clientHeight
    if (pixels < 0) { top = Math.max(0, top + pixels - 50) }
    else { bot = Math.min(cm.doc.height, bot + pixels + 50) }
    updateDisplaySimple(cm, {top: top, bottom: bot})
  }

  if (wheelSamples < 20) {
    if (display.wheelStartX == null) {
      display.wheelStartX = scroll.scrollLeft; display.wheelStartY = scroll.scrollTop
      display.wheelDX = dx; display.wheelDY = dy
      setTimeout(function () {
        if (display.wheelStartX == null) { return }
        var movedX = scroll.scrollLeft - display.wheelStartX
        var movedY = scroll.scrollTop - display.wheelStartY
        var sample = (movedY && display.wheelDY && movedY / display.wheelDY) ||
          (movedX && display.wheelDX && movedX / display.wheelDX)
        display.wheelStartX = display.wheelStartY = null
        if (!sample) { return }
        wheelPixelsPerUnit = (wheelPixelsPerUnit * wheelSamples + sample) / (wheelSamples + 1)
        ++wheelSamples
      }, 200)
    } else {
      display.wheelDX += dx; display.wheelDY += dy
    }
  }
}

// Selection objects are immutable. A new one is created every time
// the selection changes. A selection is one or more non-overlapping
// (and non-touching) ranges, sorted, and an integer that indicates
// which one is the primary selection (the one that's scrolled into
// view, that getCursor returns, etc).
var Selection = function(ranges, primIndex) {
  this.ranges = ranges
  this.primIndex = primIndex
};

Selection.prototype.primary = function () { return this.ranges[this.primIndex] };

Selection.prototype.equals = function (other) {
    var this$1 = this;

  if (other == this) { return true }
  if (other.primIndex != this.primIndex || other.ranges.length != this.ranges.length) { return false }
  for (var i = 0; i < this.ranges.length; i++) {
    var here = this$1.ranges[i], there = other.ranges[i]
    if (!equalCursorPos(here.anchor, there.anchor) || !equalCursorPos(here.head, there.head)) { return false }
  }
  return true
};

Selection.prototype.deepCopy = function () {
    var this$1 = this;

  var out = []
  for (var i = 0; i < this.ranges.length; i++)
    { out[i] = new Range(copyPos(this$1.ranges[i].anchor), copyPos(this$1.ranges[i].head)) }
  return new Selection(out, this.primIndex)
};

Selection.prototype.somethingSelected = function () {
    var this$1 = this;

  for (var i = 0; i < this.ranges.length; i++)
    { if (!this$1.ranges[i].empty()) { return true } }
  return false
};

Selection.prototype.contains = function (pos, end) {
    var this$1 = this;

  if (!end) { end = pos }
  for (var i = 0; i < this.ranges.length; i++) {
    var range = this$1.ranges[i]
    if (cmp(end, range.from()) >= 0 && cmp(pos, range.to()) <= 0)
      { return i }
  }
  return -1
};

var Range = function(anchor, head) {
  this.anchor = anchor; this.head = head
};

Range.prototype.from = function () { return minPos(this.anchor, this.head) };
Range.prototype.to = function () { return maxPos(this.anchor, this.head) };
Range.prototype.empty = function () { return this.head.line == this.anchor.line && this.head.ch == this.anchor.ch };

// Take an unsorted, potentially overlapping set of ranges, and
// build a selection out of it. 'Consumes' ranges array (modifying
// it).
function normalizeSelection(ranges, primIndex) {
  var prim = ranges[primIndex]
  ranges.sort(function (a, b) { return cmp(a.from(), b.from()); })
  primIndex = indexOf(ranges, prim)
  for (var i = 1; i < ranges.length; i++) {
    var cur = ranges[i], prev = ranges[i - 1]
    if (cmp(prev.to(), cur.from()) >= 0) {
      var from = minPos(prev.from(), cur.from()), to = maxPos(prev.to(), cur.to())
      var inv = prev.empty() ? cur.from() == cur.head : prev.from() == prev.head
      if (i <= primIndex) { --primIndex }
      ranges.splice(--i, 2, new Range(inv ? to : from, inv ? from : to))
    }
  }
  return new Selection(ranges, primIndex)
}

function simpleSelection(anchor, head) {
  return new Selection([new Range(anchor, head || anchor)], 0)
}

// Compute the position of the end of a change (its 'to' property
// refers to the pre-change end).
function changeEnd(change) {
  if (!change.text) { return change.to }
  return Pos(change.from.line + change.text.length - 1,
             lst(change.text).length + (change.text.length == 1 ? change.from.ch : 0))
}

// Adjust a position to refer to the post-change position of the
// same text, or the end of the change if the change covers it.
function adjustForChange(pos, change) {
  if (cmp(pos, change.from) < 0) { return pos }
  if (cmp(pos, change.to) <= 0) { return changeEnd(change) }

  var line = pos.line + change.text.length - (change.to.line - change.from.line) - 1, ch = pos.ch
  if (pos.line == change.to.line) { ch += changeEnd(change).ch - change.to.ch }
  return Pos(line, ch)
}

function computeSelAfterChange(doc, change) {
  var out = []
  for (var i = 0; i < doc.sel.ranges.length; i++) {
    var range = doc.sel.ranges[i]
    out.push(new Range(adjustForChange(range.anchor, change),
                       adjustForChange(range.head, change)))
  }
  return normalizeSelection(out, doc.sel.primIndex)
}

function offsetPos(pos, old, nw) {
  if (pos.line == old.line)
    { return Pos(nw.line, pos.ch - old.ch + nw.ch) }
  else
    { return Pos(nw.line + (pos.line - old.line), pos.ch) }
}

// Used by replaceSelections to allow moving the selection to the
// start or around the replaced test. Hint may be "start" or "around".
function computeReplacedSel(doc, changes, hint) {
  var out = []
  var oldPrev = Pos(doc.first, 0), newPrev = oldPrev
  for (var i = 0; i < changes.length; i++) {
    var change = changes[i]
    var from = offsetPos(change.from, oldPrev, newPrev)
    var to = offsetPos(changeEnd(change), oldPrev, newPrev)
    oldPrev = change.to
    newPrev = to
    if (hint == "around") {
      var range = doc.sel.ranges[i], inv = cmp(range.head, range.anchor) < 0
      out[i] = new Range(inv ? to : from, inv ? from : to)
    } else {
      out[i] = new Range(from, from)
    }
  }
  return new Selection(out, doc.sel.primIndex)
}

// Used to get the editor into a consistent state again when options change.

function loadMode(cm) {
  cm.doc.mode = getMode(cm.options, cm.doc.modeOption)
  resetModeState(cm)
}

function resetModeState(cm) {
  cm.doc.iter(function (line) {
    if (line.stateAfter) { line.stateAfter = null }
    if (line.styles) { line.styles = null }
  })
  cm.doc.modeFrontier = cm.doc.highlightFrontier = cm.doc.first
  startWorker(cm, 100)
  cm.state.modeGen++
  if (cm.curOp) { regChange(cm) }
}

// DOCUMENT DATA STRUCTURE

// By default, updates that start and end at the beginning of a line
// are treated specially, in order to make the association of line
// widgets and marker elements with the text behave more intuitive.
function isWholeLineUpdate(doc, change) {
  return change.from.ch == 0 && change.to.ch == 0 && lst(change.text) == "" &&
    (!doc.cm || doc.cm.options.wholeLineUpdateBefore)
}

// Perform a change on the document data structure.
function updateDoc(doc, change, markedSpans, estimateHeight) {
  function spansFor(n) {return markedSpans ? markedSpans[n] : null}
  function update(line, text, spans) {
    updateLine(line, text, spans, estimateHeight)
    signalLater(line, "change", line, change)
  }
  function linesFor(start, end) {
    var result = []
    for (var i = start; i < end; ++i)
      { result.push(new Line(text[i], spansFor(i), estimateHeight)) }
    return result
  }

  var from = change.from, to = change.to, text = change.text
  var firstLine = getLine(doc, from.line), lastLine = getLine(doc, to.line)
  var lastText = lst(text), lastSpans = spansFor(text.length - 1), nlines = to.line - from.line

  // Adjust the line structure
  if (change.full) {
    doc.insert(0, linesFor(0, text.length))
    doc.remove(text.length, doc.size - text.length)
  } else if (isWholeLineUpdate(doc, change)) {
    // This is a whole-line replace. Treated specially to make
    // sure line objects move the way they are supposed to.
    var added = linesFor(0, text.length - 1)
    update(lastLine, lastLine.text, lastSpans)
    if (nlines) { doc.remove(from.line, nlines) }
    if (added.length) { doc.insert(from.line, added) }
  } else if (firstLine == lastLine) {
    if (text.length == 1) {
      update(firstLine, firstLine.text.slice(0, from.ch) + lastText + firstLine.text.slice(to.ch), lastSpans)
    } else {
      var added$1 = linesFor(1, text.length - 1)
      added$1.push(new Line(lastText + firstLine.text.slice(to.ch), lastSpans, estimateHeight))
      update(firstLine, firstLine.text.slice(0, from.ch) + text[0], spansFor(0))
      doc.insert(from.line + 1, added$1)
    }
  } else if (text.length == 1) {
    update(firstLine, firstLine.text.slice(0, from.ch) + text[0] + lastLine.text.slice(to.ch), spansFor(0))
    doc.remove(from.line + 1, nlines)
  } else {
    update(firstLine, firstLine.text.slice(0, from.ch) + text[0], spansFor(0))
    update(lastLine, lastText + lastLine.text.slice(to.ch), lastSpans)
    var added$2 = linesFor(1, text.length - 1)
    if (nlines > 1) { doc.remove(from.line + 1, nlines - 1) }
    doc.insert(from.line + 1, added$2)
  }

  signalLater(doc, "change", doc, change)
}

// Call f for all linked documents.
function linkedDocs(doc, f, sharedHistOnly) {
  function propagate(doc, skip, sharedHist) {
    if (doc.linked) { for (var i = 0; i < doc.linked.length; ++i) {
      var rel = doc.linked[i]
      if (rel.doc == skip) { continue }
      var shared = sharedHist && rel.sharedHist
      if (sharedHistOnly && !shared) { continue }
      f(rel.doc, shared)
      propagate(rel.doc, doc, shared)
    } }
  }
  propagate(doc, null, true)
}

// Attach a document to an editor.
function attachDoc(cm, doc) {
  if (doc.cm) { throw new Error("This document is already in use.") }
  cm.doc = doc
  doc.cm = cm
  estimateLineHeights(cm)
  loadMode(cm)
  setDirectionClass(cm)
  if (!cm.options.lineWrapping) { findMaxLine(cm) }
  cm.options.mode = doc.modeOption
  regChange(cm)
}

function setDirectionClass(cm) {
  ;(cm.doc.direction == "rtl" ? addClass : rmClass)(cm.display.lineDiv, "CodeMirror-rtl")
}

function directionChanged(cm) {
  runInOp(cm, function () {
    setDirectionClass(cm)
    regChange(cm)
  })
}

function History(startGen) {
  // Arrays of change events and selections. Doing something adds an
  // event to done and clears undo. Undoing moves events from done
  // to undone, redoing moves them in the other direction.
  this.done = []; this.undone = []
  this.undoDepth = Infinity
  // Used to track when changes can be merged into a single undo
  // event
  this.lastModTime = this.lastSelTime = 0
  this.lastOp = this.lastSelOp = null
  this.lastOrigin = this.lastSelOrigin = null
  // Used by the isClean() method
  this.generation = this.maxGeneration = startGen || 1
}

// Create a history change event from an updateDoc-style change
// object.
function historyChangeFromChange(doc, change) {
  var histChange = {from: copyPos(change.from), to: changeEnd(change), text: getBetween(doc, change.from, change.to)}
  attachLocalSpans(doc, histChange, change.from.line, change.to.line + 1)
  linkedDocs(doc, function (doc) { return attachLocalSpans(doc, histChange, change.from.line, change.to.line + 1); }, true)
  return histChange
}

// Pop all selection events off the end of a history array. Stop at
// a change event.
function clearSelectionEvents(array) {
  while (array.length) {
    var last = lst(array)
    if (last.ranges) { array.pop() }
    else { break }
  }
}

// Find the top change event in the history. Pop off selection
// events that are in the way.
function lastChangeEvent(hist, force) {
  if (force) {
    clearSelectionEvents(hist.done)
    return lst(hist.done)
  } else if (hist.done.length && !lst(hist.done).ranges) {
    return lst(hist.done)
  } else if (hist.done.length > 1 && !hist.done[hist.done.length - 2].ranges) {
    hist.done.pop()
    return lst(hist.done)
  }
}

// Register a change in the history. Merges changes that are within
// a single operation, or are close together with an origin that
// allows merging (starting with "+") into a single event.
function addChangeToHistory(doc, change, selAfter, opId) {
  var hist = doc.history
  hist.undone.length = 0
  var time = +new Date, cur
  var last

  if ((hist.lastOp == opId ||
       hist.lastOrigin == change.origin && change.origin &&
       ((change.origin.charAt(0) == "+" && hist.lastModTime > time - (doc.cm ? doc.cm.options.historyEventDelay : 500)) ||
        change.origin.charAt(0) == "*")) &&
      (cur = lastChangeEvent(hist, hist.lastOp == opId))) {
    // Merge this change into the last event
    last = lst(cur.changes)
    if (cmp(change.from, change.to) == 0 && cmp(change.from, last.to) == 0) {
      // Optimized case for simple insertion -- don't want to add
      // new changesets for every character typed
      last.to = changeEnd(change)
    } else {
      // Add new sub-event
      cur.changes.push(historyChangeFromChange(doc, change))
    }
  } else {
    // Can not be merged, start a new event.
    var before = lst(hist.done)
    if (!before || !before.ranges)
      { pushSelectionToHistory(doc.sel, hist.done) }
    cur = {changes: [historyChangeFromChange(doc, change)],
           generation: hist.generation}
    hist.done.push(cur)
    while (hist.done.length > hist.undoDepth) {
      hist.done.shift()
      if (!hist.done[0].ranges) { hist.done.shift() }
    }
  }
  hist.done.push(selAfter)
  hist.generation = ++hist.maxGeneration
  hist.lastModTime = hist.lastSelTime = time
  hist.lastOp = hist.lastSelOp = opId
  hist.lastOrigin = hist.lastSelOrigin = change.origin

  if (!last) { signal(doc, "historyAdded") }
}

function selectionEventCanBeMerged(doc, origin, prev, sel) {
  var ch = origin.charAt(0)
  return ch == "*" ||
    ch == "+" &&
    prev.ranges.length == sel.ranges.length &&
    prev.somethingSelected() == sel.somethingSelected() &&
    new Date - doc.history.lastSelTime <= (doc.cm ? doc.cm.options.historyEventDelay : 500)
}

// Called whenever the selection changes, sets the new selection as
// the pending selection in the history, and pushes the old pending
// selection into the 'done' array when it was significantly
// different (in number of selected ranges, emptiness, or time).
function addSelectionToHistory(doc, sel, opId, options) {
  var hist = doc.history, origin = options && options.origin

  // A new event is started when the previous origin does not match
  // the current, or the origins don't allow matching. Origins
  // starting with * are always merged, those starting with + are
  // merged when similar and close together in time.
  if (opId == hist.lastSelOp ||
      (origin && hist.lastSelOrigin == origin &&
       (hist.lastModTime == hist.lastSelTime && hist.lastOrigin == origin ||
        selectionEventCanBeMerged(doc, origin, lst(hist.done), sel))))
    { hist.done[hist.done.length - 1] = sel }
  else
    { pushSelectionToHistory(sel, hist.done) }

  hist.lastSelTime = +new Date
  hist.lastSelOrigin = origin
  hist.lastSelOp = opId
  if (options && options.clearRedo !== false)
    { clearSelectionEvents(hist.undone) }
}

function pushSelectionToHistory(sel, dest) {
  var top = lst(dest)
  if (!(top && top.ranges && top.equals(sel)))
    { dest.push(sel) }
}

// Used to store marked span information in the history.
function attachLocalSpans(doc, change, from, to) {
  var existing = change["spans_" + doc.id], n = 0
  doc.iter(Math.max(doc.first, from), Math.min(doc.first + doc.size, to), function (line) {
    if (line.markedSpans)
      { (existing || (existing = change["spans_" + doc.id] = {}))[n] = line.markedSpans }
    ++n
  })
}

// When un/re-doing restores text containing marked spans, those
// that have been explicitly cleared should not be restored.
function removeClearedSpans(spans) {
  if (!spans) { return null }
  var out
  for (var i = 0; i < spans.length; ++i) {
    if (spans[i].marker.explicitlyCleared) { if (!out) { out = spans.slice(0, i) } }
    else if (out) { out.push(spans[i]) }
  }
  return !out ? spans : out.length ? out : null
}

// Retrieve and filter the old marked spans stored in a change event.
function getOldSpans(doc, change) {
  var found = change["spans_" + doc.id]
  if (!found) { return null }
  var nw = []
  for (var i = 0; i < change.text.length; ++i)
    { nw.push(removeClearedSpans(found[i])) }
  return nw
}

// Used for un/re-doing changes from the history. Combines the
// result of computing the existing spans with the set of spans that
// existed in the history (so that deleting around a span and then
// undoing brings back the span).
function mergeOldSpans(doc, change) {
  var old = getOldSpans(doc, change)
  var stretched = stretchSpansOverChange(doc, change)
  if (!old) { return stretched }
  if (!stretched) { return old }

  for (var i = 0; i < old.length; ++i) {
    var oldCur = old[i], stretchCur = stretched[i]
    if (oldCur && stretchCur) {
      spans: for (var j = 0; j < stretchCur.length; ++j) {
        var span = stretchCur[j]
        for (var k = 0; k < oldCur.length; ++k)
          { if (oldCur[k].marker == span.marker) { continue spans } }
        oldCur.push(span)
      }
    } else if (stretchCur) {
      old[i] = stretchCur
    }
  }
  return old
}

// Used both to provide a JSON-safe object in .getHistory, and, when
// detaching a document, to split the history in two
function copyHistoryArray(events, newGroup, instantiateSel) {
  var copy = []
  for (var i = 0; i < events.length; ++i) {
    var event = events[i]
    if (event.ranges) {
      copy.push(instantiateSel ? Selection.prototype.deepCopy.call(event) : event)
      continue
    }
    var changes = event.changes, newChanges = []
    copy.push({changes: newChanges})
    for (var j = 0; j < changes.length; ++j) {
      var change = changes[j], m = (void 0)
      newChanges.push({from: change.from, to: change.to, text: change.text})
      if (newGroup) { for (var prop in change) { if (m = prop.match(/^spans_(\d+)$/)) {
        if (indexOf(newGroup, Number(m[1])) > -1) {
          lst(newChanges)[prop] = change[prop]
          delete change[prop]
        }
      } } }
    }
  }
  return copy
}

// The 'scroll' parameter given to many of these indicated whether
// the new cursor position should be scrolled into view after
// modifying the selection.

// If shift is held or the extend flag is set, extends a range to
// include a given position (and optionally a second position).
// Otherwise, simply returns the range between the given positions.
// Used for cursor motion and such.
function extendRange(range, head, other, extend) {
  if (extend) {
    var anchor = range.anchor
    if (other) {
      var posBefore = cmp(head, anchor) < 0
      if (posBefore != (cmp(other, anchor) < 0)) {
        anchor = head
        head = other
      } else if (posBefore != (cmp(head, other) < 0)) {
        head = other
      }
    }
    return new Range(anchor, head)
  } else {
    return new Range(other || head, head)
  }
}

// Extend the primary selection range, discard the rest.
function extendSelection(doc, head, other, options, extend) {
  if (extend == null) { extend = doc.cm && (doc.cm.display.shift || doc.extend) }
  setSelection(doc, new Selection([extendRange(doc.sel.primary(), head, other, extend)], 0), options)
}

// Extend all selections (pos is an array of selections with length
// equal the number of selections)
function extendSelections(doc, heads, options) {
  var out = []
  var extend = doc.cm && (doc.cm.display.shift || doc.extend)
  for (var i = 0; i < doc.sel.ranges.length; i++)
    { out[i] = extendRange(doc.sel.ranges[i], heads[i], null, extend) }
  var newSel = normalizeSelection(out, doc.sel.primIndex)
  setSelection(doc, newSel, options)
}

// Updates a single range in the selection.
function replaceOneSelection(doc, i, range, options) {
  var ranges = doc.sel.ranges.slice(0)
  ranges[i] = range
  setSelection(doc, normalizeSelection(ranges, doc.sel.primIndex), options)
}

// Reset the selection to a single range.
function setSimpleSelection(doc, anchor, head, options) {
  setSelection(doc, simpleSelection(anchor, head), options)
}

// Give beforeSelectionChange handlers a change to influence a
// selection update.
function filterSelectionChange(doc, sel, options) {
  var obj = {
    ranges: sel.ranges,
    update: function(ranges) {
      var this$1 = this;

      this.ranges = []
      for (var i = 0; i < ranges.length; i++)
        { this$1.ranges[i] = new Range(clipPos(doc, ranges[i].anchor),
                                   clipPos(doc, ranges[i].head)) }
    },
    origin: options && options.origin
  }
  signal(doc, "beforeSelectionChange", doc, obj)
  if (doc.cm) { signal(doc.cm, "beforeSelectionChange", doc.cm, obj) }
  if (obj.ranges != sel.ranges) { return normalizeSelection(obj.ranges, obj.ranges.length - 1) }
  else { return sel }
}

function setSelectionReplaceHistory(doc, sel, options) {
  var done = doc.history.done, last = lst(done)
  if (last && last.ranges) {
    done[done.length - 1] = sel
    setSelectionNoUndo(doc, sel, options)
  } else {
    setSelection(doc, sel, options)
  }
}

// Set a new selection.
function setSelection(doc, sel, options) {
  setSelectionNoUndo(doc, sel, options)
  addSelectionToHistory(doc, doc.sel, doc.cm ? doc.cm.curOp.id : NaN, options)
}

function setSelectionNoUndo(doc, sel, options) {
  if (hasHandler(doc, "beforeSelectionChange") || doc.cm && hasHandler(doc.cm, "beforeSelectionChange"))
    { sel = filterSelectionChange(doc, sel, options) }

  var bias = options && options.bias ||
    (cmp(sel.primary().head, doc.sel.primary().head) < 0 ? -1 : 1)
  setSelectionInner(doc, skipAtomicInSelection(doc, sel, bias, true))

  if (!(options && options.scroll === false) && doc.cm)
    { ensureCursorVisible(doc.cm) }
}

function setSelectionInner(doc, sel) {
  if (sel.equals(doc.sel)) { return }

  doc.sel = sel

  if (doc.cm) {
    doc.cm.curOp.updateInput = doc.cm.curOp.selectionChanged = true
    signalCursorActivity(doc.cm)
  }
  signalLater(doc, "cursorActivity", doc)
}

// Verify that the selection does not partially select any atomic
// marked ranges.
function reCheckSelection(doc) {
  setSelectionInner(doc, skipAtomicInSelection(doc, doc.sel, null, false))
}

// Return a selection that does not partially select any atomic
// ranges.
function skipAtomicInSelection(doc, sel, bias, mayClear) {
  var out
  for (var i = 0; i < sel.ranges.length; i++) {
    var range = sel.ranges[i]
    var old = sel.ranges.length == doc.sel.ranges.length && doc.sel.ranges[i]
    var newAnchor = skipAtomic(doc, range.anchor, old && old.anchor, bias, mayClear)
    var newHead = skipAtomic(doc, range.head, old && old.head, bias, mayClear)
    if (out || newAnchor != range.anchor || newHead != range.head) {
      if (!out) { out = sel.ranges.slice(0, i) }
      out[i] = new Range(newAnchor, newHead)
    }
  }
  return out ? normalizeSelection(out, sel.primIndex) : sel
}

function skipAtomicInner(doc, pos, oldPos, dir, mayClear) {
  var line = getLine(doc, pos.line)
  if (line.markedSpans) { for (var i = 0; i < line.markedSpans.length; ++i) {
    var sp = line.markedSpans[i], m = sp.marker
    if ((sp.from == null || (m.inclusiveLeft ? sp.from <= pos.ch : sp.from < pos.ch)) &&
        (sp.to == null || (m.inclusiveRight ? sp.to >= pos.ch : sp.to > pos.ch))) {
      if (mayClear) {
        signal(m, "beforeCursorEnter")
        if (m.explicitlyCleared) {
          if (!line.markedSpans) { break }
          else {--i; continue}
        }
      }
      if (!m.atomic) { continue }

      if (oldPos) {
        var near = m.find(dir < 0 ? 1 : -1), diff = (void 0)
        if (dir < 0 ? m.inclusiveRight : m.inclusiveLeft)
          { near = movePos(doc, near, -dir, near && near.line == pos.line ? line : null) }
        if (near && near.line == pos.line && (diff = cmp(near, oldPos)) && (dir < 0 ? diff < 0 : diff > 0))
          { return skipAtomicInner(doc, near, pos, dir, mayClear) }
      }

      var far = m.find(dir < 0 ? -1 : 1)
      if (dir < 0 ? m.inclusiveLeft : m.inclusiveRight)
        { far = movePos(doc, far, dir, far.line == pos.line ? line : null) }
      return far ? skipAtomicInner(doc, far, pos, dir, mayClear) : null
    }
  } }
  return pos
}

// Ensure a given position is not inside an atomic range.
function skipAtomic(doc, pos, oldPos, bias, mayClear) {
  var dir = bias || 1
  var found = skipAtomicInner(doc, pos, oldPos, dir, mayClear) ||
      (!mayClear && skipAtomicInner(doc, pos, oldPos, dir, true)) ||
      skipAtomicInner(doc, pos, oldPos, -dir, mayClear) ||
      (!mayClear && skipAtomicInner(doc, pos, oldPos, -dir, true))
  if (!found) {
    doc.cantEdit = true
    return Pos(doc.first, 0)
  }
  return found
}

function movePos(doc, pos, dir, line) {
  if (dir < 0 && pos.ch == 0) {
    if (pos.line > doc.first) { return clipPos(doc, Pos(pos.line - 1)) }
    else { return null }
  } else if (dir > 0 && pos.ch == (line || getLine(doc, pos.line)).text.length) {
    if (pos.line < doc.first + doc.size - 1) { return Pos(pos.line + 1, 0) }
    else { return null }
  } else {
    return new Pos(pos.line, pos.ch + dir)
  }
}

function selectAll(cm) {
  cm.setSelection(Pos(cm.firstLine(), 0), Pos(cm.lastLine()), sel_dontScroll)
}

// UPDATING

// Allow "beforeChange" event handlers to influence a change
function filterChange(doc, change, update) {
  var obj = {
    canceled: false,
    from: change.from,
    to: change.to,
    text: change.text,
    origin: change.origin,
    cancel: function () { return obj.canceled = true; }
  }
  if (update) { obj.update = function (from, to, text, origin) {
    if (from) { obj.from = clipPos(doc, from) }
    if (to) { obj.to = clipPos(doc, to) }
    if (text) { obj.text = text }
    if (origin !== undefined) { obj.origin = origin }
  } }
  signal(doc, "beforeChange", doc, obj)
  if (doc.cm) { signal(doc.cm, "beforeChange", doc.cm, obj) }

  if (obj.canceled) { return null }
  return {from: obj.from, to: obj.to, text: obj.text, origin: obj.origin}
}

// Apply a change to a document, and add it to the document's
// history, and propagating it to all linked documents.
function makeChange(doc, change, ignoreReadOnly) {
  if (doc.cm) {
    if (!doc.cm.curOp) { return operation(doc.cm, makeChange)(doc, change, ignoreReadOnly) }
    if (doc.cm.state.suppressEdits) { return }
  }

  if (hasHandler(doc, "beforeChange") || doc.cm && hasHandler(doc.cm, "beforeChange")) {
    change = filterChange(doc, change, true)
    if (!change) { return }
  }

  // Possibly split or suppress the update based on the presence
  // of read-only spans in its range.
  var split = sawReadOnlySpans && !ignoreReadOnly && removeReadOnlyRanges(doc, change.from, change.to)
  if (split) {
    for (var i = split.length - 1; i >= 0; --i)
      { makeChangeInner(doc, {from: split[i].from, to: split[i].to, text: i ? [""] : change.text, origin: change.origin}) }
  } else {
    makeChangeInner(doc, change)
  }
}

function makeChangeInner(doc, change) {
  if (change.text.length == 1 && change.text[0] == "" && cmp(change.from, change.to) == 0) { return }
  var selAfter = computeSelAfterChange(doc, change)
  addChangeToHistory(doc, change, selAfter, doc.cm ? doc.cm.curOp.id : NaN)

  makeChangeSingleDoc(doc, change, selAfter, stretchSpansOverChange(doc, change))
  var rebased = []

  linkedDocs(doc, function (doc, sharedHist) {
    if (!sharedHist && indexOf(rebased, doc.history) == -1) {
      rebaseHist(doc.history, change)
      rebased.push(doc.history)
    }
    makeChangeSingleDoc(doc, change, null, stretchSpansOverChange(doc, change))
  })
}

// Revert a change stored in a document's history.
function makeChangeFromHistory(doc, type, allowSelectionOnly) {
  var suppress = doc.cm && doc.cm.state.suppressEdits
  if (suppress && !allowSelectionOnly) { return }

  var hist = doc.history, event, selAfter = doc.sel
  var source = type == "undo" ? hist.done : hist.undone, dest = type == "undo" ? hist.undone : hist.done

  // Verify that there is a useable event (so that ctrl-z won't
  // needlessly clear selection events)
  var i = 0
  for (; i < source.length; i++) {
    event = source[i]
    if (allowSelectionOnly ? event.ranges && !event.equals(doc.sel) : !event.ranges)
      { break }
  }
  if (i == source.length) { return }
  hist.lastOrigin = hist.lastSelOrigin = null

  for (;;) {
    event = source.pop()
    if (event.ranges) {
      pushSelectionToHistory(event, dest)
      if (allowSelectionOnly && !event.equals(doc.sel)) {
        setSelection(doc, event, {clearRedo: false})
        return
      }
      selAfter = event
    } else if (suppress) {
      source.push(event)
      return
    } else { break }
  }

  // Build up a reverse change object to add to the opposite history
  // stack (redo when undoing, and vice versa).
  var antiChanges = []
  pushSelectionToHistory(selAfter, dest)
  dest.push({changes: antiChanges, generation: hist.generation})
  hist.generation = event.generation || ++hist.maxGeneration

  var filter = hasHandler(doc, "beforeChange") || doc.cm && hasHandler(doc.cm, "beforeChange")

  var loop = function ( i ) {
    var change = event.changes[i]
    change.origin = type
    if (filter && !filterChange(doc, change, false)) {
      source.length = 0
      return {}
    }

    antiChanges.push(historyChangeFromChange(doc, change))

    var after = i ? computeSelAfterChange(doc, change) : lst(source)
    makeChangeSingleDoc(doc, change, after, mergeOldSpans(doc, change))
    if (!i && doc.cm) { doc.cm.scrollIntoView({from: change.from, to: changeEnd(change)}) }
    var rebased = []

    // Propagate to the linked documents
    linkedDocs(doc, function (doc, sharedHist) {
      if (!sharedHist && indexOf(rebased, doc.history) == -1) {
        rebaseHist(doc.history, change)
        rebased.push(doc.history)
      }
      makeChangeSingleDoc(doc, change, null, mergeOldSpans(doc, change))
    })
  };

  for (var i$1 = event.changes.length - 1; i$1 >= 0; --i$1) {
    var returned = loop( i$1 );

    if ( returned ) return returned.v;
  }
}

// Sub-views need their line numbers shifted when text is added
// above or below them in the parent document.
function shiftDoc(doc, distance) {
  if (distance == 0) { return }
  doc.first += distance
  doc.sel = new Selection(map(doc.sel.ranges, function (range) { return new Range(
    Pos(range.anchor.line + distance, range.anchor.ch),
    Pos(range.head.line + distance, range.head.ch)
  ); }), doc.sel.primIndex)
  if (doc.cm) {
    regChange(doc.cm, doc.first, doc.first - distance, distance)
    for (var d = doc.cm.display, l = d.viewFrom; l < d.viewTo; l++)
      { regLineChange(doc.cm, l, "gutter") }
  }
}

// More lower-level change function, handling only a single document
// (not linked ones).
function makeChangeSingleDoc(doc, change, selAfter, spans) {
  if (doc.cm && !doc.cm.curOp)
    { return operation(doc.cm, makeChangeSingleDoc)(doc, change, selAfter, spans) }

  if (change.to.line < doc.first) {
    shiftDoc(doc, change.text.length - 1 - (change.to.line - change.from.line))
    return
  }
  if (change.from.line > doc.lastLine()) { return }

  // Clip the change to the size of this doc
  if (change.from.line < doc.first) {
    var shift = change.text.length - 1 - (doc.first - change.from.line)
    shiftDoc(doc, shift)
    change = {from: Pos(doc.first, 0), to: Pos(change.to.line + shift, change.to.ch),
              text: [lst(change.text)], origin: change.origin}
  }
  var last = doc.lastLine()
  if (change.to.line > last) {
    change = {from: change.from, to: Pos(last, getLine(doc, last).text.length),
              text: [change.text[0]], origin: change.origin}
  }

  change.removed = getBetween(doc, change.from, change.to)

  if (!selAfter) { selAfter = computeSelAfterChange(doc, change) }
  if (doc.cm) { makeChangeSingleDocInEditor(doc.cm, change, spans) }
  else { updateDoc(doc, change, spans) }
  setSelectionNoUndo(doc, selAfter, sel_dontScroll)
}

// Handle the interaction of a change to a document with the editor
// that this document is part of.
function makeChangeSingleDocInEditor(cm, change, spans) {
  var doc = cm.doc, display = cm.display, from = change.from, to = change.to

  var recomputeMaxLength = false, checkWidthStart = from.line
  if (!cm.options.lineWrapping) {
    checkWidthStart = lineNo(visualLine(getLine(doc, from.line)))
    doc.iter(checkWidthStart, to.line + 1, function (line) {
      if (line == display.maxLine) {
        recomputeMaxLength = true
        return true
      }
    })
  }

  if (doc.sel.contains(change.from, change.to) > -1)
    { signalCursorActivity(cm) }

  updateDoc(doc, change, spans, estimateHeight(cm))

  if (!cm.options.lineWrapping) {
    doc.iter(checkWidthStart, from.line + change.text.length, function (line) {
      var len = lineLength(line)
      if (len > display.maxLineLength) {
        display.maxLine = line
        display.maxLineLength = len
        display.maxLineChanged = true
        recomputeMaxLength = false
      }
    })
    if (recomputeMaxLength) { cm.curOp.updateMaxLine = true }
  }

  retreatFrontier(doc, from.line)
  startWorker(cm, 400)

  var lendiff = change.text.length - (to.line - from.line) - 1
  // Remember that these lines changed, for updating the display
  if (change.full)
    { regChange(cm) }
  else if (from.line == to.line && change.text.length == 1 && !isWholeLineUpdate(cm.doc, change))
    { regLineChange(cm, from.line, "text") }
  else
    { regChange(cm, from.line, to.line + 1, lendiff) }

  var changesHandler = hasHandler(cm, "changes"), changeHandler = hasHandler(cm, "change")
  if (changeHandler || changesHandler) {
    var obj = {
      from: from, to: to,
      text: change.text,
      removed: change.removed,
      origin: change.origin
    }
    if (changeHandler) { signalLater(cm, "change", cm, obj) }
    if (changesHandler) { (cm.curOp.changeObjs || (cm.curOp.changeObjs = [])).push(obj) }
  }
  cm.display.selForContextMenu = null
}

function replaceRange(doc, code, from, to, origin) {
  if (!to) { to = from }
  if (cmp(to, from) < 0) { var assign;
    (assign = [to, from], from = assign[0], to = assign[1], assign) }
  if (typeof code == "string") { code = doc.splitLines(code) }
  makeChange(doc, {from: from, to: to, text: code, origin: origin})
}

// Rebasing/resetting history to deal with externally-sourced changes

function rebaseHistSelSingle(pos, from, to, diff) {
  if (to < pos.line) {
    pos.line += diff
  } else if (from < pos.line) {
    pos.line = from
    pos.ch = 0
  }
}

// Tries to rebase an array of history events given a change in the
// document. If the change touches the same lines as the event, the
// event, and everything 'behind' it, is discarded. If the change is
// before the event, the event's positions are updated. Uses a
// copy-on-write scheme for the positions, to avoid having to
// reallocate them all on every rebase, but also avoid problems with
// shared position objects being unsafely updated.
function rebaseHistArray(array, from, to, diff) {
  for (var i = 0; i < array.length; ++i) {
    var sub = array[i], ok = true
    if (sub.ranges) {
      if (!sub.copied) { sub = array[i] = sub.deepCopy(); sub.copied = true }
      for (var j = 0; j < sub.ranges.length; j++) {
        rebaseHistSelSingle(sub.ranges[j].anchor, from, to, diff)
        rebaseHistSelSingle(sub.ranges[j].head, from, to, diff)
      }
      continue
    }
    for (var j$1 = 0; j$1 < sub.changes.length; ++j$1) {
      var cur = sub.changes[j$1]
      if (to < cur.from.line) {
        cur.from = Pos(cur.from.line + diff, cur.from.ch)
        cur.to = Pos(cur.to.line + diff, cur.to.ch)
      } else if (from <= cur.to.line) {
        ok = false
        break
      }
    }
    if (!ok) {
      array.splice(0, i + 1)
      i = 0
    }
  }
}

function rebaseHist(hist, change) {
  var from = change.from.line, to = change.to.line, diff = change.text.length - (to - from) - 1
  rebaseHistArray(hist.done, from, to, diff)
  rebaseHistArray(hist.undone, from, to, diff)
}

// Utility for applying a change to a line by handle or number,
// returning the number and optionally registering the line as
// changed.
function changeLine(doc, handle, changeType, op) {
  var no = handle, line = handle
  if (typeof handle == "number") { line = getLine(doc, clipLine(doc, handle)) }
  else { no = lineNo(handle) }
  if (no == null) { return null }
  if (op(line, no) && doc.cm) { regLineChange(doc.cm, no, changeType) }
  return line
}

// The document is represented as a BTree consisting of leaves, with
// chunk of lines in them, and branches, with up to ten leaves or
// other branch nodes below them. The top node is always a branch
// node, and is the document object itself (meaning it has
// additional methods and properties).
//
// All nodes have parent links. The tree is used both to go from
// line numbers to line objects, and to go from objects to numbers.
// It also indexes by height, and is used to convert between height
// and line object, and to find the total height of the document.
//
// See also http://marijnhaverbeke.nl/blog/codemirror-line-tree.html

function LeafChunk(lines) {
  var this$1 = this;

  this.lines = lines
  this.parent = null
  var height = 0
  for (var i = 0; i < lines.length; ++i) {
    lines[i].parent = this$1
    height += lines[i].height
  }
  this.height = height
}

LeafChunk.prototype = {
  chunkSize: function chunkSize() { return this.lines.length },

  // Remove the n lines at offset 'at'.
  removeInner: function removeInner(at, n) {
    var this$1 = this;

    for (var i = at, e = at + n; i < e; ++i) {
      var line = this$1.lines[i]
      this$1.height -= line.height
      cleanUpLine(line)
      signalLater(line, "delete")
    }
    this.lines.splice(at, n)
  },

  // Helper used to collapse a small branch into a single leaf.
  collapse: function collapse(lines) {
    lines.push.apply(lines, this.lines)
  },

  // Insert the given array of lines at offset 'at', count them as
  // having the given height.
  insertInner: function insertInner(at, lines, height) {
    var this$1 = this;

    this.height += height
    this.lines = this.lines.slice(0, at).concat(lines).concat(this.lines.slice(at))
    for (var i = 0; i < lines.length; ++i) { lines[i].parent = this$1 }
  },

  // Used to iterate over a part of the tree.
  iterN: function iterN(at, n, op) {
    var this$1 = this;

    for (var e = at + n; at < e; ++at)
      { if (op(this$1.lines[at])) { return true } }
  }
}

function BranchChunk(children) {
  var this$1 = this;

  this.children = children
  var size = 0, height = 0
  for (var i = 0; i < children.length; ++i) {
    var ch = children[i]
    size += ch.chunkSize(); height += ch.height
    ch.parent = this$1
  }
  this.size = size
  this.height = height
  this.parent = null
}

BranchChunk.prototype = {
  chunkSize: function chunkSize() { return this.size },

  removeInner: function removeInner(at, n) {
    var this$1 = this;

    this.size -= n
    for (var i = 0; i < this.children.length; ++i) {
      var child = this$1.children[i], sz = child.chunkSize()
      if (at < sz) {
        var rm = Math.min(n, sz - at), oldHeight = child.height
        child.removeInner(at, rm)
        this$1.height -= oldHeight - child.height
        if (sz == rm) { this$1.children.splice(i--, 1); child.parent = null }
        if ((n -= rm) == 0) { break }
        at = 0
      } else { at -= sz }
    }
    // If the result is smaller than 25 lines, ensure that it is a
    // single leaf node.
    if (this.size - n < 25 &&
        (this.children.length > 1 || !(this.children[0] instanceof LeafChunk))) {
      var lines = []
      this.collapse(lines)
      this.children = [new LeafChunk(lines)]
      this.children[0].parent = this
    }
  },

  collapse: function collapse(lines) {
    var this$1 = this;

    for (var i = 0; i < this.children.length; ++i) { this$1.children[i].collapse(lines) }
  },

  insertInner: function insertInner(at, lines, height) {
    var this$1 = this;

    this.size += lines.length
    this.height += height
    for (var i = 0; i < this.children.length; ++i) {
      var child = this$1.children[i], sz = child.chunkSize()
      if (at <= sz) {
        child.insertInner(at, lines, height)
        if (child.lines && child.lines.length > 50) {
          // To avoid memory thrashing when child.lines is huge (e.g. first view of a large file), it's never spliced.
          // Instead, small slices are taken. They're taken in order because sequential memory accesses are fastest.
          var remaining = child.lines.length % 25 + 25
          for (var pos = remaining; pos < child.lines.length;) {
            var leaf = new LeafChunk(child.lines.slice(pos, pos += 25))
            child.height -= leaf.height
            this$1.children.splice(++i, 0, leaf)
            leaf.parent = this$1
          }
          child.lines = child.lines.slice(0, remaining)
          this$1.maybeSpill()
        }
        break
      }
      at -= sz
    }
  },

  // When a node has grown, check whether it should be split.
  maybeSpill: function maybeSpill() {
    if (this.children.length <= 10) { return }
    var me = this
    do {
      var spilled = me.children.splice(me.children.length - 5, 5)
      var sibling = new BranchChunk(spilled)
      if (!me.parent) { // Become the parent node
        var copy = new BranchChunk(me.children)
        copy.parent = me
        me.children = [copy, sibling]
        me = copy
     } else {
        me.size -= sibling.size
        me.height -= sibling.height
        var myIndex = indexOf(me.parent.children, me)
        me.parent.children.splice(myIndex + 1, 0, sibling)
      }
      sibling.parent = me.parent
    } while (me.children.length > 10)
    me.parent.maybeSpill()
  },

  iterN: function iterN(at, n, op) {
    var this$1 = this;

    for (var i = 0; i < this.children.length; ++i) {
      var child = this$1.children[i], sz = child.chunkSize()
      if (at < sz) {
        var used = Math.min(n, sz - at)
        if (child.iterN(at, used, op)) { return true }
        if ((n -= used) == 0) { break }
        at = 0
      } else { at -= sz }
    }
  }
}

// Line widgets are block elements displayed above or below a line.

var LineWidget = function(doc, node, options) {
  var this$1 = this;

  if (options) { for (var opt in options) { if (options.hasOwnProperty(opt))
    { this$1[opt] = options[opt] } } }
  this.doc = doc
  this.node = node
};

LineWidget.prototype.clear = function () {
    var this$1 = this;

  var cm = this.doc.cm, ws = this.line.widgets, line = this.line, no = lineNo(line)
  if (no == null || !ws) { return }
  for (var i = 0; i < ws.length; ++i) { if (ws[i] == this$1) { ws.splice(i--, 1) } }
  if (!ws.length) { line.widgets = null }
  var height = widgetHeight(this)
  updateLineHeight(line, Math.max(0, line.height - height))
  if (cm) {
    runInOp(cm, function () {
      adjustScrollWhenAboveVisible(cm, line, -height)
      regLineChange(cm, no, "widget")
    })
    signalLater(cm, "lineWidgetCleared", cm, this, no)
  }
};

LineWidget.prototype.changed = function () {
    var this$1 = this;

  var oldH = this.height, cm = this.doc.cm, line = this.line
  this.height = null
  var diff = widgetHeight(this) - oldH
  if (!diff) { return }
  if (!lineIsHidden(this.doc, line)) { updateLineHeight(line, line.height + diff) }
  if (cm) {
    runInOp(cm, function () {
      cm.curOp.forceUpdate = true
      adjustScrollWhenAboveVisible(cm, line, diff)
      signalLater(cm, "lineWidgetChanged", cm, this$1, lineNo(line))
    })
  }
};
eventMixin(LineWidget)

function adjustScrollWhenAboveVisible(cm, line, diff) {
  if (heightAtLine(line) < ((cm.curOp && cm.curOp.scrollTop) || cm.doc.scrollTop))
    { addToScrollTop(cm, diff) }
}

function addLineWidget(doc, handle, node, options) {
  var widget = new LineWidget(doc, node, options)
  var cm = doc.cm
  if (cm && widget.noHScroll) { cm.display.alignWidgets = true }
  changeLine(doc, handle, "widget", function (line) {
    var widgets = line.widgets || (line.widgets = [])
    if (widget.insertAt == null) { widgets.push(widget) }
    else { widgets.splice(Math.min(widgets.length - 1, Math.max(0, widget.insertAt)), 0, widget) }
    widget.line = line
    if (cm && !lineIsHidden(doc, line)) {
      var aboveVisible = heightAtLine(line) < doc.scrollTop
      updateLineHeight(line, line.height + widgetHeight(widget))
      if (aboveVisible) { addToScrollTop(cm, widget.height) }
      cm.curOp.forceUpdate = true
    }
    return true
  })
  if (cm) { signalLater(cm, "lineWidgetAdded", cm, widget, typeof handle == "number" ? handle : lineNo(handle)) }
  return widget
}

// TEXTMARKERS

// Created with markText and setBookmark methods. A TextMarker is a
// handle that can be used to clear or find a marked position in the
// document. Line objects hold arrays (markedSpans) containing
// {from, to, marker} object pointing to such marker objects, and
// indicating that such a marker is present on that line. Multiple
// lines may point to the same marker when it spans across lines.
// The spans will have null for their from/to properties when the
// marker continues beyond the start/end of the line. Markers have
// links back to the lines they currently touch.

// Collapsed markers have unique ids, in order to be able to order
// them, which is needed for uniquely determining an outer marker
// when they overlap (they may nest, but not partially overlap).
var nextMarkerId = 0

var TextMarker = function(doc, type) {
  this.lines = []
  this.type = type
  this.doc = doc
  this.id = ++nextMarkerId
};

// Clear the marker.
TextMarker.prototype.clear = function () {
    var this$1 = this;

  if (this.explicitlyCleared) { return }
  var cm = this.doc.cm, withOp = cm && !cm.curOp
  if (withOp) { startOperation(cm) }
  if (hasHandler(this, "clear")) {
    var found = this.find()
    if (found) { signalLater(this, "clear", found.from, found.to) }
  }
  var min = null, max = null
  for (var i = 0; i < this.lines.length; ++i) {
    var line = this$1.lines[i]
    var span = getMarkedSpanFor(line.markedSpans, this$1)
    if (cm && !this$1.collapsed) { regLineChange(cm, lineNo(line), "text") }
    else if (cm) {
      if (span.to != null) { max = lineNo(line) }
      if (span.from != null) { min = lineNo(line) }
    }
    line.markedSpans = removeMarkedSpan(line.markedSpans, span)
    if (span.from == null && this$1.collapsed && !lineIsHidden(this$1.doc, line) && cm)
      { updateLineHeight(line, textHeight(cm.display)) }
  }
  if (cm && this.collapsed && !cm.options.lineWrapping) { for (var i$1 = 0; i$1 < this.lines.length; ++i$1) {
    var visual = visualLine(this$1.lines[i$1]), len = lineLength(visual)
    if (len > cm.display.maxLineLength) {
      cm.display.maxLine = visual
      cm.display.maxLineLength = len
      cm.display.maxLineChanged = true
    }
  } }

  if (min != null && cm && this.collapsed) { regChange(cm, min, max + 1) }
  this.lines.length = 0
  this.explicitlyCleared = true
  if (this.atomic && this.doc.cantEdit) {
    this.doc.cantEdit = false
    if (cm) { reCheckSelection(cm.doc) }
  }
  if (cm) { signalLater(cm, "markerCleared", cm, this, min, max) }
  if (withOp) { endOperation(cm) }
  if (this.parent) { this.parent.clear() }
};

// Find the position of the marker in the document. Returns a {from,
// to} object by default. Side can be passed to get a specific side
// -- 0 (both), -1 (left), or 1 (right). When lineObj is true, the
// Pos objects returned contain a line object, rather than a line
// number (used to prevent looking up the same line twice).
TextMarker.prototype.find = function (side, lineObj) {
    var this$1 = this;

  if (side == null && this.type == "bookmark") { side = 1 }
  var from, to
  for (var i = 0; i < this.lines.length; ++i) {
    var line = this$1.lines[i]
    var span = getMarkedSpanFor(line.markedSpans, this$1)
    if (span.from != null) {
      from = Pos(lineObj ? line : lineNo(line), span.from)
      if (side == -1) { return from }
    }
    if (span.to != null) {
      to = Pos(lineObj ? line : lineNo(line), span.to)
      if (side == 1) { return to }
    }
  }
  return from && {from: from, to: to}
};

// Signals that the marker's widget changed, and surrounding layout
// should be recomputed.
TextMarker.prototype.changed = function () {
    var this$1 = this;

  var pos = this.find(-1, true), widget = this, cm = this.doc.cm
  if (!pos || !cm) { return }
  runInOp(cm, function () {
    var line = pos.line, lineN = lineNo(pos.line)
    var view = findViewForLine(cm, lineN)
    if (view) {
      clearLineMeasurementCacheFor(view)
      cm.curOp.selectionChanged = cm.curOp.forceUpdate = true
    }
    cm.curOp.updateMaxLine = true
    if (!lineIsHidden(widget.doc, line) && widget.height != null) {
      var oldHeight = widget.height
      widget.height = null
      var dHeight = widgetHeight(widget) - oldHeight
      if (dHeight)
        { updateLineHeight(line, line.height + dHeight) }
    }
    signalLater(cm, "markerChanged", cm, this$1)
  })
};

TextMarker.prototype.attachLine = function (line) {
  if (!this.lines.length && this.doc.cm) {
    var op = this.doc.cm.curOp
    if (!op.maybeHiddenMarkers || indexOf(op.maybeHiddenMarkers, this) == -1)
      { (op.maybeUnhiddenMarkers || (op.maybeUnhiddenMarkers = [])).push(this) }
  }
  this.lines.push(line)
};

TextMarker.prototype.detachLine = function (line) {
  this.lines.splice(indexOf(this.lines, line), 1)
  if (!this.lines.length && this.doc.cm) {
    var op = this.doc.cm.curOp
    ;(op.maybeHiddenMarkers || (op.maybeHiddenMarkers = [])).push(this)
  }
};
eventMixin(TextMarker)

// Create a marker, wire it up to the right lines, and
function markText(doc, from, to, options, type) {
  // Shared markers (across linked documents) are handled separately
  // (markTextShared will call out to this again, once per
  // document).
  if (options && options.shared) { return markTextShared(doc, from, to, options, type) }
  // Ensure we are in an operation.
  if (doc.cm && !doc.cm.curOp) { return operation(doc.cm, markText)(doc, from, to, options, type) }

  var marker = new TextMarker(doc, type), diff = cmp(from, to)
  if (options) { copyObj(options, marker, false) }
  // Don't connect empty markers unless clearWhenEmpty is false
  if (diff > 0 || diff == 0 && marker.clearWhenEmpty !== false)
    { return marker }
  if (marker.replacedWith) {
    // Showing up as a widget implies collapsed (widget replaces text)
    marker.collapsed = true
    marker.widgetNode = eltP("span", [marker.replacedWith], "CodeMirror-widget")
    if (!options.handleMouseEvents) { marker.widgetNode.setAttribute("cm-ignore-events", "true") }
    if (options.insertLeft) { marker.widgetNode.insertLeft = true }
  }
  if (marker.collapsed) {
    if (conflictingCollapsedRange(doc, from.line, from, to, marker) ||
        from.line != to.line && conflictingCollapsedRange(doc, to.line, from, to, marker))
      { throw new Error("Inserting collapsed marker partially overlapping an existing one") }
    seeCollapsedSpans()
  }

  if (marker.addToHistory)
    { addChangeToHistory(doc, {from: from, to: to, origin: "markText"}, doc.sel, NaN) }

  var curLine = from.line, cm = doc.cm, updateMaxLine
  doc.iter(curLine, to.line + 1, function (line) {
    if (cm && marker.collapsed && !cm.options.lineWrapping && visualLine(line) == cm.display.maxLine)
      { updateMaxLine = true }
    if (marker.collapsed && curLine != from.line) { updateLineHeight(line, 0) }
    addMarkedSpan(line, new MarkedSpan(marker,
                                       curLine == from.line ? from.ch : null,
                                       curLine == to.line ? to.ch : null))
    ++curLine
  })
  // lineIsHidden depends on the presence of the spans, so needs a second pass
  if (marker.collapsed) { doc.iter(from.line, to.line + 1, function (line) {
    if (lineIsHidden(doc, line)) { updateLineHeight(line, 0) }
  }) }

  if (marker.clearOnEnter) { on(marker, "beforeCursorEnter", function () { return marker.clear(); }) }

  if (marker.readOnly) {
    seeReadOnlySpans()
    if (doc.history.done.length || doc.history.undone.length)
      { doc.clearHistory() }
  }
  if (marker.collapsed) {
    marker.id = ++nextMarkerId
    marker.atomic = true
  }
  if (cm) {
    // Sync editor state
    if (updateMaxLine) { cm.curOp.updateMaxLine = true }
    if (marker.collapsed)
      { regChange(cm, from.line, to.line + 1) }
    else if (marker.className || marker.title || marker.startStyle || marker.endStyle || marker.css)
      { for (var i = from.line; i <= to.line; i++) { regLineChange(cm, i, "text") } }
    if (marker.atomic) { reCheckSelection(cm.doc) }
    signalLater(cm, "markerAdded", cm, marker)
  }
  return marker
}

// SHARED TEXTMARKERS

// A shared marker spans multiple linked documents. It is
// implemented as a meta-marker-object controlling multiple normal
// markers.
var SharedTextMarker = function(markers, primary) {
  var this$1 = this;

  this.markers = markers
  this.primary = primary
  for (var i = 0; i < markers.length; ++i)
    { markers[i].parent = this$1 }
};

SharedTextMarker.prototype.clear = function () {
    var this$1 = this;

  if (this.explicitlyCleared) { return }
  this.explicitlyCleared = true
  for (var i = 0; i < this.markers.length; ++i)
    { this$1.markers[i].clear() }
  signalLater(this, "clear")
};

SharedTextMarker.prototype.find = function (side, lineObj) {
  return this.primary.find(side, lineObj)
};
eventMixin(SharedTextMarker)

function markTextShared(doc, from, to, options, type) {
  options = copyObj(options)
  options.shared = false
  var markers = [markText(doc, from, to, options, type)], primary = markers[0]
  var widget = options.widgetNode
  linkedDocs(doc, function (doc) {
    if (widget) { options.widgetNode = widget.cloneNode(true) }
    markers.push(markText(doc, clipPos(doc, from), clipPos(doc, to), options, type))
    for (var i = 0; i < doc.linked.length; ++i)
      { if (doc.linked[i].isParent) { return } }
    primary = lst(markers)
  })
  return new SharedTextMarker(markers, primary)
}

function findSharedMarkers(doc) {
  return doc.findMarks(Pos(doc.first, 0), doc.clipPos(Pos(doc.lastLine())), function (m) { return m.parent; })
}

function copySharedMarkers(doc, markers) {
  for (var i = 0; i < markers.length; i++) {
    var marker = markers[i], pos = marker.find()
    var mFrom = doc.clipPos(pos.from), mTo = doc.clipPos(pos.to)
    if (cmp(mFrom, mTo)) {
      var subMark = markText(doc, mFrom, mTo, marker.primary, marker.primary.type)
      marker.markers.push(subMark)
      subMark.parent = marker
    }
  }
}

function detachSharedMarkers(markers) {
  var loop = function ( i ) {
    var marker = markers[i], linked = [marker.primary.doc]
    linkedDocs(marker.primary.doc, function (d) { return linked.push(d); })
    for (var j = 0; j < marker.markers.length; j++) {
      var subMarker = marker.markers[j]
      if (indexOf(linked, subMarker.doc) == -1) {
        subMarker.parent = null
        marker.markers.splice(j--, 1)
      }
    }
  };

  for (var i = 0; i < markers.length; i++) loop( i );
}

var nextDocId = 0
var Doc = function(text, mode, firstLine, lineSep, direction) {
  if (!(this instanceof Doc)) { return new Doc(text, mode, firstLine, lineSep, direction) }
  if (firstLine == null) { firstLine = 0 }

  BranchChunk.call(this, [new LeafChunk([new Line("", null)])])
  this.first = firstLine
  this.scrollTop = this.scrollLeft = 0
  this.cantEdit = false
  this.cleanGeneration = 1
  this.modeFrontier = this.highlightFrontier = firstLine
  var start = Pos(firstLine, 0)
  this.sel = simpleSelection(start)
  this.history = new History(null)
  this.id = ++nextDocId
  this.modeOption = mode
  this.lineSep = lineSep
  this.direction = (direction == "rtl") ? "rtl" : "ltr"
  this.extend = false

  if (typeof text == "string") { text = this.splitLines(text) }
  updateDoc(this, {from: start, to: start, text: text})
  setSelection(this, simpleSelection(start), sel_dontScroll)
}

Doc.prototype = createObj(BranchChunk.prototype, {
  constructor: Doc,
  // Iterate over the document. Supports two forms -- with only one
  // argument, it calls that for each line in the document. With
  // three, it iterates over the range given by the first two (with
  // the second being non-inclusive).
  iter: function(from, to, op) {
    if (op) { this.iterN(from - this.first, to - from, op) }
    else { this.iterN(this.first, this.first + this.size, from) }
  },

  // Non-public interface for adding and removing lines.
  insert: function(at, lines) {
    var height = 0
    for (var i = 0; i < lines.length; ++i) { height += lines[i].height }
    this.insertInner(at - this.first, lines, height)
  },
  remove: function(at, n) { this.removeInner(at - this.first, n) },

  // From here, the methods are part of the public interface. Most
  // are also available from CodeMirror (editor) instances.

  getValue: function(lineSep) {
    var lines = getLines(this, this.first, this.first + this.size)
    if (lineSep === false) { return lines }
    return lines.join(lineSep || this.lineSeparator())
  },
  setValue: docMethodOp(function(code) {
    var top = Pos(this.first, 0), last = this.first + this.size - 1
    makeChange(this, {from: top, to: Pos(last, getLine(this, last).text.length),
                      text: this.splitLines(code), origin: "setValue", full: true}, true)
    if (this.cm) { scrollToCoords(this.cm, 0, 0) }
    setSelection(this, simpleSelection(top), sel_dontScroll)
  }),
  replaceRange: function(code, from, to, origin) {
    from = clipPos(this, from)
    to = to ? clipPos(this, to) : from
    replaceRange(this, code, from, to, origin)
  },
  getRange: function(from, to, lineSep) {
    var lines = getBetween(this, clipPos(this, from), clipPos(this, to))
    if (lineSep === false) { return lines }
    return lines.join(lineSep || this.lineSeparator())
  },

  getLine: function(line) {var l = this.getLineHandle(line); return l && l.text},

  getLineHandle: function(line) {if (isLine(this, line)) { return getLine(this, line) }},
  getLineNumber: function(line) {return lineNo(line)},

  getLineHandleVisualStart: function(line) {
    if (typeof line == "number") { line = getLine(this, line) }
    return visualLine(line)
  },

  lineCount: function() {return this.size},
  firstLine: function() {return this.first},
  lastLine: function() {return this.first + this.size - 1},

  clipPos: function(pos) {return clipPos(this, pos)},

  getCursor: function(start) {
    var range = this.sel.primary(), pos
    if (start == null || start == "head") { pos = range.head }
    else if (start == "anchor") { pos = range.anchor }
    else if (start == "end" || start == "to" || start === false) { pos = range.to() }
    else { pos = range.from() }
    return pos
  },
  listSelections: function() { return this.sel.ranges },
  somethingSelected: function() {return this.sel.somethingSelected()},

  setCursor: docMethodOp(function(line, ch, options) {
    setSimpleSelection(this, clipPos(this, typeof line == "number" ? Pos(line, ch || 0) : line), null, options)
  }),
  setSelection: docMethodOp(function(anchor, head, options) {
    setSimpleSelection(this, clipPos(this, anchor), clipPos(this, head || anchor), options)
  }),
  extendSelection: docMethodOp(function(head, other, options) {
    extendSelection(this, clipPos(this, head), other && clipPos(this, other), options)
  }),
  extendSelections: docMethodOp(function(heads, options) {
    extendSelections(this, clipPosArray(this, heads), options)
  }),
  extendSelectionsBy: docMethodOp(function(f, options) {
    var heads = map(this.sel.ranges, f)
    extendSelections(this, clipPosArray(this, heads), options)
  }),
  setSelections: docMethodOp(function(ranges, primary, options) {
    var this$1 = this;

    if (!ranges.length) { return }
    var out = []
    for (var i = 0; i < ranges.length; i++)
      { out[i] = new Range(clipPos(this$1, ranges[i].anchor),
                         clipPos(this$1, ranges[i].head)) }
    if (primary == null) { primary = Math.min(ranges.length - 1, this.sel.primIndex) }
    setSelection(this, normalizeSelection(out, primary), options)
  }),
  addSelection: docMethodOp(function(anchor, head, options) {
    var ranges = this.sel.ranges.slice(0)
    ranges.push(new Range(clipPos(this, anchor), clipPos(this, head || anchor)))
    setSelection(this, normalizeSelection(ranges, ranges.length - 1), options)
  }),

  getSelection: function(lineSep) {
    var this$1 = this;

    var ranges = this.sel.ranges, lines
    for (var i = 0; i < ranges.length; i++) {
      var sel = getBetween(this$1, ranges[i].from(), ranges[i].to())
      lines = lines ? lines.concat(sel) : sel
    }
    if (lineSep === false) { return lines }
    else { return lines.join(lineSep || this.lineSeparator()) }
  },
  getSelections: function(lineSep) {
    var this$1 = this;

    var parts = [], ranges = this.sel.ranges
    for (var i = 0; i < ranges.length; i++) {
      var sel = getBetween(this$1, ranges[i].from(), ranges[i].to())
      if (lineSep !== false) { sel = sel.join(lineSep || this$1.lineSeparator()) }
      parts[i] = sel
    }
    return parts
  },
  replaceSelection: function(code, collapse, origin) {
    var dup = []
    for (var i = 0; i < this.sel.ranges.length; i++)
      { dup[i] = code }
    this.replaceSelections(dup, collapse, origin || "+input")
  },
  replaceSelections: docMethodOp(function(code, collapse, origin) {
    var this$1 = this;

    var changes = [], sel = this.sel
    for (var i = 0; i < sel.ranges.length; i++) {
      var range = sel.ranges[i]
      changes[i] = {from: range.from(), to: range.to(), text: this$1.splitLines(code[i]), origin: origin}
    }
    var newSel = collapse && collapse != "end" && computeReplacedSel(this, changes, collapse)
    for (var i$1 = changes.length - 1; i$1 >= 0; i$1--)
      { makeChange(this$1, changes[i$1]) }
    if (newSel) { setSelectionReplaceHistory(this, newSel) }
    else if (this.cm) { ensureCursorVisible(this.cm) }
  }),
  undo: docMethodOp(function() {makeChangeFromHistory(this, "undo")}),
  redo: docMethodOp(function() {makeChangeFromHistory(this, "redo")}),
  undoSelection: docMethodOp(function() {makeChangeFromHistory(this, "undo", true)}),
  redoSelection: docMethodOp(function() {makeChangeFromHistory(this, "redo", true)}),

  setExtending: function(val) {this.extend = val},
  getExtending: function() {return this.extend},

  historySize: function() {
    var hist = this.history, done = 0, undone = 0
    for (var i = 0; i < hist.done.length; i++) { if (!hist.done[i].ranges) { ++done } }
    for (var i$1 = 0; i$1 < hist.undone.length; i$1++) { if (!hist.undone[i$1].ranges) { ++undone } }
    return {undo: done, redo: undone}
  },
  clearHistory: function() {this.history = new History(this.history.maxGeneration)},

  markClean: function() {
    this.cleanGeneration = this.changeGeneration(true)
  },
  changeGeneration: function(forceSplit) {
    if (forceSplit)
      { this.history.lastOp = this.history.lastSelOp = this.history.lastOrigin = null }
    return this.history.generation
  },
  isClean: function (gen) {
    return this.history.generation == (gen || this.cleanGeneration)
  },

  getHistory: function() {
    return {done: copyHistoryArray(this.history.done),
            undone: copyHistoryArray(this.history.undone)}
  },
  setHistory: function(histData) {
    var hist = this.history = new History(this.history.maxGeneration)
    hist.done = copyHistoryArray(histData.done.slice(0), null, true)
    hist.undone = copyHistoryArray(histData.undone.slice(0), null, true)
  },

  setGutterMarker: docMethodOp(function(line, gutterID, value) {
    return changeLine(this, line, "gutter", function (line) {
      var markers = line.gutterMarkers || (line.gutterMarkers = {})
      markers[gutterID] = value
      if (!value && isEmpty(markers)) { line.gutterMarkers = null }
      return true
    })
  }),

  clearGutter: docMethodOp(function(gutterID) {
    var this$1 = this;

    this.iter(function (line) {
      if (line.gutterMarkers && line.gutterMarkers[gutterID]) {
        changeLine(this$1, line, "gutter", function () {
          line.gutterMarkers[gutterID] = null
          if (isEmpty(line.gutterMarkers)) { line.gutterMarkers = null }
          return true
        })
      }
    })
  }),

  lineInfo: function(line) {
    var n
    if (typeof line == "number") {
      if (!isLine(this, line)) { return null }
      n = line
      line = getLine(this, line)
      if (!line) { return null }
    } else {
      n = lineNo(line)
      if (n == null) { return null }
    }
    return {line: n, handle: line, text: line.text, gutterMarkers: line.gutterMarkers,
            textClass: line.textClass, bgClass: line.bgClass, wrapClass: line.wrapClass,
            widgets: line.widgets}
  },

  addLineClass: docMethodOp(function(handle, where, cls) {
    return changeLine(this, handle, where == "gutter" ? "gutter" : "class", function (line) {
      var prop = where == "text" ? "textClass"
               : where == "background" ? "bgClass"
               : where == "gutter" ? "gutterClass" : "wrapClass"
      if (!line[prop]) { line[prop] = cls }
      else if (classTest(cls).test(line[prop])) { return false }
      else { line[prop] += " " + cls }
      return true
    })
  }),
  removeLineClass: docMethodOp(function(handle, where, cls) {
    return changeLine(this, handle, where == "gutter" ? "gutter" : "class", function (line) {
      var prop = where == "text" ? "textClass"
               : where == "background" ? "bgClass"
               : where == "gutter" ? "gutterClass" : "wrapClass"
      var cur = line[prop]
      if (!cur) { return false }
      else if (cls == null) { line[prop] = null }
      else {
        var found = cur.match(classTest(cls))
        if (!found) { return false }
        var end = found.index + found[0].length
        line[prop] = cur.slice(0, found.index) + (!found.index || end == cur.length ? "" : " ") + cur.slice(end) || null
      }
      return true
    })
  }),

  addLineWidget: docMethodOp(function(handle, node, options) {
    return addLineWidget(this, handle, node, options)
  }),
  removeLineWidget: function(widget) { widget.clear() },

  markText: function(from, to, options) {
    return markText(this, clipPos(this, from), clipPos(this, to), options, options && options.type || "range")
  },
  setBookmark: function(pos, options) {
    var realOpts = {replacedWith: options && (options.nodeType == null ? options.widget : options),
                    insertLeft: options && options.insertLeft,
                    clearWhenEmpty: false, shared: options && options.shared,
                    handleMouseEvents: options && options.handleMouseEvents}
    pos = clipPos(this, pos)
    return markText(this, pos, pos, realOpts, "bookmark")
  },
  findMarksAt: function(pos) {
    pos = clipPos(this, pos)
    var markers = [], spans = getLine(this, pos.line).markedSpans
    if (spans) { for (var i = 0; i < spans.length; ++i) {
      var span = spans[i]
      if ((span.from == null || span.from <= pos.ch) &&
          (span.to == null || span.to >= pos.ch))
        { markers.push(span.marker.parent || span.marker) }
    } }
    return markers
  },
  findMarks: function(from, to, filter) {
    from = clipPos(this, from); to = clipPos(this, to)
    var found = [], lineNo = from.line
    this.iter(from.line, to.line + 1, function (line) {
      var spans = line.markedSpans
      if (spans) { for (var i = 0; i < spans.length; i++) {
        var span = spans[i]
        if (!(span.to != null && lineNo == from.line && from.ch >= span.to ||
              span.from == null && lineNo != from.line ||
              span.from != null && lineNo == to.line && span.from >= to.ch) &&
            (!filter || filter(span.marker)))
          { found.push(span.marker.parent || span.marker) }
      } }
      ++lineNo
    })
    return found
  },
  getAllMarks: function() {
    var markers = []
    this.iter(function (line) {
      var sps = line.markedSpans
      if (sps) { for (var i = 0; i < sps.length; ++i)
        { if (sps[i].from != null) { markers.push(sps[i].marker) } } }
    })
    return markers
  },

  posFromIndex: function(off) {
    var ch, lineNo = this.first, sepSize = this.lineSeparator().length
    this.iter(function (line) {
      var sz = line.text.length + sepSize
      if (sz > off) { ch = off; return true }
      off -= sz
      ++lineNo
    })
    return clipPos(this, Pos(lineNo, ch))
  },
  indexFromPos: function (coords) {
    coords = clipPos(this, coords)
    var index = coords.ch
    if (coords.line < this.first || coords.ch < 0) { return 0 }
    var sepSize = this.lineSeparator().length
    this.iter(this.first, coords.line, function (line) { // iter aborts when callback returns a truthy value
      index += line.text.length + sepSize
    })
    return index
  },

  copy: function(copyHistory) {
    var doc = new Doc(getLines(this, this.first, this.first + this.size),
                      this.modeOption, this.first, this.lineSep, this.direction)
    doc.scrollTop = this.scrollTop; doc.scrollLeft = this.scrollLeft
    doc.sel = this.sel
    doc.extend = false
    if (copyHistory) {
      doc.history.undoDepth = this.history.undoDepth
      doc.setHistory(this.getHistory())
    }
    return doc
  },

  linkedDoc: function(options) {
    if (!options) { options = {} }
    var from = this.first, to = this.first + this.size
    if (options.from != null && options.from > from) { from = options.from }
    if (options.to != null && options.to < to) { to = options.to }
    var copy = new Doc(getLines(this, from, to), options.mode || this.modeOption, from, this.lineSep, this.direction)
    if (options.sharedHist) { copy.history = this.history
    ; }(this.linked || (this.linked = [])).push({doc: copy, sharedHist: options.sharedHist})
    copy.linked = [{doc: this, isParent: true, sharedHist: options.sharedHist}]
    copySharedMarkers(copy, findSharedMarkers(this))
    return copy
  },
  unlinkDoc: function(other) {
    var this$1 = this;

    if (other instanceof CodeMirror) { other = other.doc }
    if (this.linked) { for (var i = 0; i < this.linked.length; ++i) {
      var link = this$1.linked[i]
      if (link.doc != other) { continue }
      this$1.linked.splice(i, 1)
      other.unlinkDoc(this$1)
      detachSharedMarkers(findSharedMarkers(this$1))
      break
    } }
    // If the histories were shared, split them again
    if (other.history == this.history) {
      var splitIds = [other.id]
      linkedDocs(other, function (doc) { return splitIds.push(doc.id); }, true)
      other.history = new History(null)
      other.history.done = copyHistoryArray(this.history.done, splitIds)
      other.history.undone = copyHistoryArray(this.history.undone, splitIds)
    }
  },
  iterLinkedDocs: function(f) {linkedDocs(this, f)},

  getMode: function() {return this.mode},
  getEditor: function() {return this.cm},

  splitLines: function(str) {
    if (this.lineSep) { return str.split(this.lineSep) }
    return splitLinesAuto(str)
  },
  lineSeparator: function() { return this.lineSep || "\n" },

  setDirection: docMethodOp(function (dir) {
    if (dir != "rtl") { dir = "ltr" }
    if (dir == this.direction) { return }
    this.direction = dir
    this.iter(function (line) { return line.order = null; })
    if (this.cm) { directionChanged(this.cm) }
  })
})

// Public alias.
Doc.prototype.eachLine = Doc.prototype.iter

// Kludge to work around strange IE behavior where it'll sometimes
// re-fire a series of drag-related events right after the drop (#1551)
var lastDrop = 0

function onDrop(e) {
  var cm = this
  clearDragCursor(cm)
  if (signalDOMEvent(cm, e) || eventInWidget(cm.display, e))
    { return }
  e_preventDefault(e)
  if (ie) { lastDrop = +new Date }
  var pos = posFromMouse(cm, e, true), files = e.dataTransfer.files
  if (!pos || cm.isReadOnly()) { return }
  // Might be a file drop, in which case we simply extract the text
  // and insert it.
  if (files && files.length && window.FileReader && window.File) {
    var n = files.length, text = Array(n), read = 0
    var loadFile = function (file, i) {
      if (cm.options.allowDropFileTypes &&
          indexOf(cm.options.allowDropFileTypes, file.type) == -1)
        { return }

      var reader = new FileReader
      reader.onload = operation(cm, function () {
        var content = reader.result
        if (/[\x00-\x08\x0e-\x1f]{2}/.test(content)) { content = "" }
        text[i] = content
        if (++read == n) {
          pos = clipPos(cm.doc, pos)
          var change = {from: pos, to: pos,
                        text: cm.doc.splitLines(text.join(cm.doc.lineSeparator())),
                        origin: "paste"}
          makeChange(cm.doc, change)
          setSelectionReplaceHistory(cm.doc, simpleSelection(pos, changeEnd(change)))
        }
      })
      reader.readAsText(file)
    }
    for (var i = 0; i < n; ++i) { loadFile(files[i], i) }
  } else { // Normal drop
    // Don't do a replace if the drop happened inside of the selected text.
    if (cm.state.draggingText && cm.doc.sel.contains(pos) > -1) {
      cm.state.draggingText(e)
      // Ensure the editor is re-focused
      setTimeout(function () { return cm.display.input.focus(); }, 20)
      return
    }
    try {
      var text$1 = e.dataTransfer.getData("Text")
      if (text$1) {
        var selected
        if (cm.state.draggingText && !cm.state.draggingText.copy)
          { selected = cm.listSelections() }
        setSelectionNoUndo(cm.doc, simpleSelection(pos, pos))
        if (selected) { for (var i$1 = 0; i$1 < selected.length; ++i$1)
          { replaceRange(cm.doc, "", selected[i$1].anchor, selected[i$1].head, "drag") } }
        cm.replaceSelection(text$1, "around", "paste")
        cm.display.input.focus()
      }
    }
    catch(e){}
  }
}

function onDragStart(cm, e) {
  if (ie && (!cm.state.draggingText || +new Date - lastDrop < 100)) { e_stop(e); return }
  if (signalDOMEvent(cm, e) || eventInWidget(cm.display, e)) { return }

  e.dataTransfer.setData("Text", cm.getSelection())
  e.dataTransfer.effectAllowed = "copyMove"

  // Use dummy image instead of default browsers image.
  // Recent Safari (~6.0.2) have a tendency to segfault when this happens, so we don't do it there.
  if (e.dataTransfer.setDragImage && !safari) {
    var img = elt("img", null, null, "position: fixed; left: 0; top: 0;")
    img.src = "data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw=="
    if (presto) {
      img.width = img.height = 1
      cm.display.wrapper.appendChild(img)
      // Force a relayout, or Opera won't use our image for some obscure reason
      img._top = img.offsetTop
    }
    e.dataTransfer.setDragImage(img, 0, 0)
    if (presto) { img.parentNode.removeChild(img) }
  }
}

function onDragOver(cm, e) {
  var pos = posFromMouse(cm, e)
  if (!pos) { return }
  var frag = document.createDocumentFragment()
  drawSelectionCursor(cm, pos, frag)
  if (!cm.display.dragCursor) {
    cm.display.dragCursor = elt("div", null, "CodeMirror-cursors CodeMirror-dragcursors")
    cm.display.lineSpace.insertBefore(cm.display.dragCursor, cm.display.cursorDiv)
  }
  removeChildrenAndAdd(cm.display.dragCursor, frag)
}

function clearDragCursor(cm) {
  if (cm.display.dragCursor) {
    cm.display.lineSpace.removeChild(cm.display.dragCursor)
    cm.display.dragCursor = null
  }
}

// These must be handled carefully, because naively registering a
// handler for each editor will cause the editors to never be
// garbage collected.

function forEachCodeMirror(f) {
  if (!document.getElementsByClassName) { return }
  var byClass = document.getElementsByClassName("CodeMirror")
  for (var i = 0; i < byClass.length; i++) {
    var cm = byClass[i].CodeMirror
    if (cm) { f(cm) }
  }
}

var globalsRegistered = false
function ensureGlobalHandlers() {
  if (globalsRegistered) { return }
  registerGlobalHandlers()
  globalsRegistered = true
}
function registerGlobalHandlers() {
  // When the window resizes, we need to refresh active editors.
  var resizeTimer
  on(window, "resize", function () {
    if (resizeTimer == null) { resizeTimer = setTimeout(function () {
      resizeTimer = null
      forEachCodeMirror(onResize)
    }, 100) }
  })
  // When the window loses focus, we want to show the editor as blurred
  on(window, "blur", function () { return forEachCodeMirror(onBlur); })
}
// Called when the window resizes
function onResize(cm) {
  var d = cm.display
  // Might be a text scaling operation, clear size caches.
  d.cachedCharWidth = d.cachedTextHeight = d.cachedPaddingH = null
  d.scrollbarsClipped = false
  cm.setSize()
}

var keyNames = {
  3: "Pause", 8: "Backspace", 9: "Tab", 13: "Enter", 16: "Shift", 17: "Ctrl", 18: "Alt",
  19: "Pause", 20: "CapsLock", 27: "Esc", 32: "Space", 33: "PageUp", 34: "PageDown", 35: "End",
  36: "Home", 37: "Left", 38: "Up", 39: "Right", 40: "Down", 44: "PrintScrn", 45: "Insert",
  46: "Delete", 59: ";", 61: "=", 91: "Mod", 92: "Mod", 93: "Mod",
  106: "*", 107: "=", 109: "-", 110: ".", 111: "/", 127: "Delete", 145: "ScrollLock",
  173: "-", 186: ";", 187: "=", 188: ",", 189: "-", 190: ".", 191: "/", 192: "`", 219: "[", 220: "\\",
  221: "]", 222: "'", 63232: "Up", 63233: "Down", 63234: "Left", 63235: "Right", 63272: "Delete",
  63273: "Home", 63275: "End", 63276: "PageUp", 63277: "PageDown", 63302: "Insert"
}

// Number keys
for (var i = 0; i < 10; i++) { keyNames[i + 48] = keyNames[i + 96] = String(i) }
// Alphabetic keys
for (var i$1 = 65; i$1 <= 90; i$1++) { keyNames[i$1] = String.fromCharCode(i$1) }
// Function keys
for (var i$2 = 1; i$2 <= 12; i$2++) { keyNames[i$2 + 111] = keyNames[i$2 + 63235] = "F" + i$2 }

var keyMap = {}

keyMap.basic = {
  "Left": "goCharLeft", "Right": "goCharRight", "Up": "goLineUp", "Down": "goLineDown",
  "End": "goLineEnd", "Home": "goLineStartSmart", "PageUp": "goPageUp", "PageDown": "goPageDown",
  "Delete": "delCharAfter", "Backspace": "delCharBefore", "Shift-Backspace": "delCharBefore",
  "Tab": "defaultTab", "Shift-Tab": "indentAuto",
  "Enter": "newlineAndIndent", "Insert": "toggleOverwrite",
  "Esc": "singleSelection"
}
// Note that the save and find-related commands aren't defined by
// default. User code or addons can define them. Unknown commands
// are simply ignored.
keyMap.pcDefault = {
  "Ctrl-A": "selectAll", "Ctrl-D": "deleteLine", "Ctrl-Z": "undo", "Shift-Ctrl-Z": "redo", "Ctrl-Y": "redo",
  "Ctrl-Home": "goDocStart", "Ctrl-End": "goDocEnd", "Ctrl-Up": "goLineUp", "Ctrl-Down": "goLineDown",
  "Ctrl-Left": "goGroupLeft", "Ctrl-Right": "goGroupRight", "Alt-Left": "goLineStart", "Alt-Right": "goLineEnd",
  "Ctrl-Backspace": "delGroupBefore", "Ctrl-Delete": "delGroupAfter", "Ctrl-S": "save", "Ctrl-F": "find",
  "Ctrl-G": "findNext", "Shift-Ctrl-G": "findPrev", "Shift-Ctrl-F": "replace", "Shift-Ctrl-R": "replaceAll",
  "Ctrl-[": "indentLess", "Ctrl-]": "indentMore",
  "Ctrl-U": "undoSelection", "Shift-Ctrl-U": "redoSelection", "Alt-U": "redoSelection",
  "fallthrough": "basic"
}
// Very basic readline/emacs-style bindings, which are standard on Mac.
keyMap.emacsy = {
  "Ctrl-F": "goCharRight", "Ctrl-B": "goCharLeft", "Ctrl-P": "goLineUp", "Ctrl-N": "goLineDown",
  "Alt-F": "goWordRight", "Alt-B": "goWordLeft", "Ctrl-A": "goLineStart", "Ctrl-E": "goLineEnd",
  "Ctrl-V": "goPageDown", "Shift-Ctrl-V": "goPageUp", "Ctrl-D": "delCharAfter", "Ctrl-H": "delCharBefore",
  "Alt-D": "delWordAfter", "Alt-Backspace": "delWordBefore", "Ctrl-K": "killLine", "Ctrl-T": "transposeChars",
  "Ctrl-O": "openLine"
}
keyMap.macDefault = {
  "Cmd-A": "selectAll", "Cmd-D": "deleteLine", "Cmd-Z": "undo", "Shift-Cmd-Z": "redo", "Cmd-Y": "redo",
  "Cmd-Home": "goDocStart", "Cmd-Up": "goDocStart", "Cmd-End": "goDocEnd", "Cmd-Down": "goDocEnd", "Alt-Left": "goGroupLeft",
  "Alt-Right": "goGroupRight", "Cmd-Left": "goLineLeft", "Cmd-Right": "goLineRight", "Alt-Backspace": "delGroupBefore",
  "Ctrl-Alt-Backspace": "delGroupAfter", "Alt-Delete": "delGroupAfter", "Cmd-S": "save", "Cmd-F": "find",
  "Cmd-G": "findNext", "Shift-Cmd-G": "findPrev", "Cmd-Alt-F": "replace", "Shift-Cmd-Alt-F": "replaceAll",
  "Cmd-[": "indentLess", "Cmd-]": "indentMore", "Cmd-Backspace": "delWrappedLineLeft", "Cmd-Delete": "delWrappedLineRight",
  "Cmd-U": "undoSelection", "Shift-Cmd-U": "redoSelection", "Ctrl-Up": "goDocStart", "Ctrl-Down": "goDocEnd",
  "fallthrough": ["basic", "emacsy"]
}
keyMap["default"] = mac ? keyMap.macDefault : keyMap.pcDefault

// KEYMAP DISPATCH

function normalizeKeyName(name) {
  var parts = name.split(/-(?!$)/)
  name = parts[parts.length - 1]
  var alt, ctrl, shift, cmd
  for (var i = 0; i < parts.length - 1; i++) {
    var mod = parts[i]
    if (/^(cmd|meta|m)$/i.test(mod)) { cmd = true }
    else if (/^a(lt)?$/i.test(mod)) { alt = true }
    else if (/^(c|ctrl|control)$/i.test(mod)) { ctrl = true }
    else if (/^s(hift)?$/i.test(mod)) { shift = true }
    else { throw new Error("Unrecognized modifier name: " + mod) }
  }
  if (alt) { name = "Alt-" + name }
  if (ctrl) { name = "Ctrl-" + name }
  if (cmd) { name = "Cmd-" + name }
  if (shift) { name = "Shift-" + name }
  return name
}

// This is a kludge to keep keymaps mostly working as raw objects
// (backwards compatibility) while at the same time support features
// like normalization and multi-stroke key bindings. It compiles a
// new normalized keymap, and then updates the old object to reflect
// this.
function normalizeKeyMap(keymap) {
  var copy = {}
  for (var keyname in keymap) { if (keymap.hasOwnProperty(keyname)) {
    var value = keymap[keyname]
    if (/^(name|fallthrough|(de|at)tach)$/.test(keyname)) { continue }
    if (value == "...") { delete keymap[keyname]; continue }

    var keys = map(keyname.split(" "), normalizeKeyName)
    for (var i = 0; i < keys.length; i++) {
      var val = (void 0), name = (void 0)
      if (i == keys.length - 1) {
        name = keys.join(" ")
        val = value
      } else {
        name = keys.slice(0, i + 1).join(" ")
        val = "..."
      }
      var prev = copy[name]
      if (!prev) { copy[name] = val }
      else if (prev != val) { throw new Error("Inconsistent bindings for " + name) }
    }
    delete keymap[keyname]
  } }
  for (var prop in copy) { keymap[prop] = copy[prop] }
  return keymap
}

function lookupKey(key, map, handle, context) {
  map = getKeyMap(map)
  var found = map.call ? map.call(key, context) : map[key]
  if (found === false) { return "nothing" }
  if (found === "...") { return "multi" }
  if (found != null && handle(found)) { return "handled" }

  if (map.fallthrough) {
    if (Object.prototype.toString.call(map.fallthrough) != "[object Array]")
      { return lookupKey(key, map.fallthrough, handle, context) }
    for (var i = 0; i < map.fallthrough.length; i++) {
      var result = lookupKey(key, map.fallthrough[i], handle, context)
      if (result) { return result }
    }
  }
}

// Modifier key presses don't count as 'real' key presses for the
// purpose of keymap fallthrough.
function isModifierKey(value) {
  var name = typeof value == "string" ? value : keyNames[value.keyCode]
  return name == "Ctrl" || name == "Alt" || name == "Shift" || name == "Mod"
}

function addModifierNames(name, event, noShift) {
  var base = name
  if (event.altKey && base != "Alt") { name = "Alt-" + name }
  if ((flipCtrlCmd ? event.metaKey : event.ctrlKey) && base != "Ctrl") { name = "Ctrl-" + name }
  if ((flipCtrlCmd ? event.ctrlKey : event.metaKey) && base != "Cmd") { name = "Cmd-" + name }
  if (!noShift && event.shiftKey && base != "Shift") { name = "Shift-" + name }
  return name
}

// Look up the name of a key as indicated by an event object.
function keyName(event, noShift) {
  if (presto && event.keyCode == 34 && event["char"]) { return false }
  var name = keyNames[event.keyCode]
  if (name == null || event.altGraphKey) { return false }
  // Ctrl-ScrollLock has keyCode 3, same as Ctrl-Pause,
  // so we'll use event.code when available (Chrome 48+, FF 38+, Safari 10.1+)
  if (event.keyCode == 3 && event.code) { name = event.code }
  return addModifierNames(name, event, noShift)
}

function getKeyMap(val) {
  return typeof val == "string" ? keyMap[val] : val
}

// Helper for deleting text near the selection(s), used to implement
// backspace, delete, and similar functionality.
function deleteNearSelection(cm, compute) {
  var ranges = cm.doc.sel.ranges, kill = []
  // Build up a set of ranges to kill first, merging overlapping
  // ranges.
  for (var i = 0; i < ranges.length; i++) {
    var toKill = compute(ranges[i])
    while (kill.length && cmp(toKill.from, lst(kill).to) <= 0) {
      var replaced = kill.pop()
      if (cmp(replaced.from, toKill.from) < 0) {
        toKill.from = replaced.from
        break
      }
    }
    kill.push(toKill)
  }
  // Next, remove those actual ranges.
  runInOp(cm, function () {
    for (var i = kill.length - 1; i >= 0; i--)
      { replaceRange(cm.doc, "", kill[i].from, kill[i].to, "+delete") }
    ensureCursorVisible(cm)
  })
}

function moveCharLogically(line, ch, dir) {
  var target = skipExtendingChars(line.text, ch + dir, dir)
  return target < 0 || target > line.text.length ? null : target
}

function moveLogically(line, start, dir) {
  var ch = moveCharLogically(line, start.ch, dir)
  return ch == null ? null : new Pos(start.line, ch, dir < 0 ? "after" : "before")
}

function endOfLine(visually, cm, lineObj, lineNo, dir) {
  if (visually) {
    var order = getOrder(lineObj, cm.doc.direction)
    if (order) {
      var part = dir < 0 ? lst(order) : order[0]
      var moveInStorageOrder = (dir < 0) == (part.level == 1)
      var sticky = moveInStorageOrder ? "after" : "before"
      var ch
      // With a wrapped rtl chunk (possibly spanning multiple bidi parts),
      // it could be that the last bidi part is not on the last visual line,
      // since visual lines contain content order-consecutive chunks.
      // Thus, in rtl, we are looking for the first (content-order) character
      // in the rtl chunk that is on the last line (that is, the same line
      // as the last (content-order) character).
      if (part.level > 0 || cm.doc.direction == "rtl") {
        var prep = prepareMeasureForLine(cm, lineObj)
        ch = dir < 0 ? lineObj.text.length - 1 : 0
        var targetTop = measureCharPrepared(cm, prep, ch).top
        ch = findFirst(function (ch) { return measureCharPrepared(cm, prep, ch).top == targetTop; }, (dir < 0) == (part.level == 1) ? part.from : part.to - 1, ch)
        if (sticky == "before") { ch = moveCharLogically(lineObj, ch, 1) }
      } else { ch = dir < 0 ? part.to : part.from }
      return new Pos(lineNo, ch, sticky)
    }
  }
  return new Pos(lineNo, dir < 0 ? lineObj.text.length : 0, dir < 0 ? "before" : "after")
}

function moveVisually(cm, line, start, dir) {
  var bidi = getOrder(line, cm.doc.direction)
  if (!bidi) { return moveLogically(line, start, dir) }
  if (start.ch >= line.text.length) {
    start.ch = line.text.length
    start.sticky = "before"
  } else if (start.ch <= 0) {
    start.ch = 0
    start.sticky = "after"
  }
  var partPos = getBidiPartAt(bidi, start.ch, start.sticky), part = bidi[partPos]
  if (cm.doc.direction == "ltr" && part.level % 2 == 0 && (dir > 0 ? part.to > start.ch : part.from < start.ch)) {
    // Case 1: We move within an ltr part in an ltr editor. Even with wrapped lines,
    // nothing interesting happens.
    return moveLogically(line, start, dir)
  }

  var mv = function (pos, dir) { return moveCharLogically(line, pos instanceof Pos ? pos.ch : pos, dir); }
  var prep
  var getWrappedLineExtent = function (ch) {
    if (!cm.options.lineWrapping) { return {begin: 0, end: line.text.length} }
    prep = prep || prepareMeasureForLine(cm, line)
    return wrappedLineExtentChar(cm, line, prep, ch)
  }
  var wrappedLineExtent = getWrappedLineExtent(start.sticky == "before" ? mv(start, -1) : start.ch)

  if (cm.doc.direction == "rtl" || part.level == 1) {
    var moveInStorageOrder = (part.level == 1) == (dir < 0)
    var ch = mv(start, moveInStorageOrder ? 1 : -1)
    if (ch != null && (!moveInStorageOrder ? ch >= part.from && ch >= wrappedLineExtent.begin : ch <= part.to && ch <= wrappedLineExtent.end)) {
      // Case 2: We move within an rtl part or in an rtl editor on the same visual line
      var sticky = moveInStorageOrder ? "before" : "after"
      return new Pos(start.line, ch, sticky)
    }
  }

  // Case 3: Could not move within this bidi part in this visual line, so leave
  // the current bidi part

  var searchInVisualLine = function (partPos, dir, wrappedLineExtent) {
    var getRes = function (ch, moveInStorageOrder) { return moveInStorageOrder
      ? new Pos(start.line, mv(ch, 1), "before")
      : new Pos(start.line, ch, "after"); }

    for (; partPos >= 0 && partPos < bidi.length; partPos += dir) {
      var part = bidi[partPos]
      var moveInStorageOrder = (dir > 0) == (part.level != 1)
      var ch = moveInStorageOrder ? wrappedLineExtent.begin : mv(wrappedLineExtent.end, -1)
      if (part.from <= ch && ch < part.to) { return getRes(ch, moveInStorageOrder) }
      ch = moveInStorageOrder ? part.from : mv(part.to, -1)
      if (wrappedLineExtent.begin <= ch && ch < wrappedLineExtent.end) { return getRes(ch, moveInStorageOrder) }
    }
  }

  // Case 3a: Look for other bidi parts on the same visual line
  var res = searchInVisualLine(partPos + dir, dir, wrappedLineExtent)
  if (res) { return res }

  // Case 3b: Look for other bidi parts on the next visual line
  var nextCh = dir > 0 ? wrappedLineExtent.end : mv(wrappedLineExtent.begin, -1)
  if (nextCh != null && !(dir > 0 && nextCh == line.text.length)) {
    res = searchInVisualLine(dir > 0 ? 0 : bidi.length - 1, dir, getWrappedLineExtent(nextCh))
    if (res) { return res }
  }

  // Case 4: Nowhere to move
  return null
}

// Commands are parameter-less actions that can be performed on an
// editor, mostly used for keybindings.
var commands = {
  selectAll: selectAll,
  singleSelection: function (cm) { return cm.setSelection(cm.getCursor("anchor"), cm.getCursor("head"), sel_dontScroll); },
  killLine: function (cm) { return deleteNearSelection(cm, function (range) {
    if (range.empty()) {
      var len = getLine(cm.doc, range.head.line).text.length
      if (range.head.ch == len && range.head.line < cm.lastLine())
        { return {from: range.head, to: Pos(range.head.line + 1, 0)} }
      else
        { return {from: range.head, to: Pos(range.head.line, len)} }
    } else {
      return {from: range.from(), to: range.to()}
    }
  }); },
  deleteLine: function (cm) { return deleteNearSelection(cm, function (range) { return ({
    from: Pos(range.from().line, 0),
    to: clipPos(cm.doc, Pos(range.to().line + 1, 0))
  }); }); },
  delLineLeft: function (cm) { return deleteNearSelection(cm, function (range) { return ({
    from: Pos(range.from().line, 0), to: range.from()
  }); }); },
  delWrappedLineLeft: function (cm) { return deleteNearSelection(cm, function (range) {
    var top = cm.charCoords(range.head, "div").top + 5
    var leftPos = cm.coordsChar({left: 0, top: top}, "div")
    return {from: leftPos, to: range.from()}
  }); },
  delWrappedLineRight: function (cm) { return deleteNearSelection(cm, function (range) {
    var top = cm.charCoords(range.head, "div").top + 5
    var rightPos = cm.coordsChar({left: cm.display.lineDiv.offsetWidth + 100, top: top}, "div")
    return {from: range.from(), to: rightPos }
  }); },
  undo: function (cm) { return cm.undo(); },
  redo: function (cm) { return cm.redo(); },
  undoSelection: function (cm) { return cm.undoSelection(); },
  redoSelection: function (cm) { return cm.redoSelection(); },
  goDocStart: function (cm) { return cm.extendSelection(Pos(cm.firstLine(), 0)); },
  goDocEnd: function (cm) { return cm.extendSelection(Pos(cm.lastLine())); },
  goLineStart: function (cm) { return cm.extendSelectionsBy(function (range) { return lineStart(cm, range.head.line); },
    {origin: "+move", bias: 1}
  ); },
  goLineStartSmart: function (cm) { return cm.extendSelectionsBy(function (range) { return lineStartSmart(cm, range.head); },
    {origin: "+move", bias: 1}
  ); },
  goLineEnd: function (cm) { return cm.extendSelectionsBy(function (range) { return lineEnd(cm, range.head.line); },
    {origin: "+move", bias: -1}
  ); },
  goLineRight: function (cm) { return cm.extendSelectionsBy(function (range) {
    var top = cm.cursorCoords(range.head, "div").top + 5
    return cm.coordsChar({left: cm.display.lineDiv.offsetWidth + 100, top: top}, "div")
  }, sel_move); },
  goLineLeft: function (cm) { return cm.extendSelectionsBy(function (range) {
    var top = cm.cursorCoords(range.head, "div").top + 5
    return cm.coordsChar({left: 0, top: top}, "div")
  }, sel_move); },
  goLineLeftSmart: function (cm) { return cm.extendSelectionsBy(function (range) {
    var top = cm.cursorCoords(range.head, "div").top + 5
    var pos = cm.coordsChar({left: 0, top: top}, "div")
    if (pos.ch < cm.getLine(pos.line).search(/\S/)) { return lineStartSmart(cm, range.head) }
    return pos
  }, sel_move); },
  goLineUp: function (cm) { return cm.moveV(-1, "line"); },
  goLineDown: function (cm) { return cm.moveV(1, "line"); },
  goPageUp: function (cm) { return cm.moveV(-1, "page"); },
  goPageDown: function (cm) { return cm.moveV(1, "page"); },
  goCharLeft: function (cm) { return cm.moveH(-1, "char"); },
  goCharRight: function (cm) { return cm.moveH(1, "char"); },
  goColumnLeft: function (cm) { return cm.moveH(-1, "column"); },
  goColumnRight: function (cm) { return cm.moveH(1, "column"); },
  goWordLeft: function (cm) { return cm.moveH(-1, "word"); },
  goGroupRight: function (cm) { return cm.moveH(1, "group"); },
  goGroupLeft: function (cm) { return cm.moveH(-1, "group"); },
  goWordRight: function (cm) { return cm.moveH(1, "word"); },
  delCharBefore: function (cm) { return cm.deleteH(-1, "char"); },
  delCharAfter: function (cm) { return cm.deleteH(1, "char"); },
  delWordBefore: function (cm) { return cm.deleteH(-1, "word"); },
  delWordAfter: function (cm) { return cm.deleteH(1, "word"); },
  delGroupBefore: function (cm) { return cm.deleteH(-1, "group"); },
  delGroupAfter: function (cm) { return cm.deleteH(1, "group"); },
  indentAuto: function (cm) { return cm.indentSelection("smart"); },
  indentMore: function (cm) { return cm.indentSelection("add"); },
  indentLess: function (cm) { return cm.indentSelection("subtract"); },
  insertTab: function (cm) { return cm.replaceSelection("\t"); },
  insertSoftTab: function (cm) {
    var spaces = [], ranges = cm.listSelections(), tabSize = cm.options.tabSize
    for (var i = 0; i < ranges.length; i++) {
      var pos = ranges[i].from()
      var col = countColumn(cm.getLine(pos.line), pos.ch, tabSize)
      spaces.push(spaceStr(tabSize - col % tabSize))
    }
    cm.replaceSelections(spaces)
  },
  defaultTab: function (cm) {
    if (cm.somethingSelected()) { cm.indentSelection("add") }
    else { cm.execCommand("insertTab") }
  },
  // Swap the two chars left and right of each selection's head.
  // Move cursor behind the two swapped characters afterwards.
  //
  // Doesn't consider line feeds a character.
  // Doesn't scan more than one line above to find a character.
  // Doesn't do anything on an empty line.
  // Doesn't do anything with non-empty selections.
  transposeChars: function (cm) { return runInOp(cm, function () {
    var ranges = cm.listSelections(), newSel = []
    for (var i = 0; i < ranges.length; i++) {
      if (!ranges[i].empty()) { continue }
      var cur = ranges[i].head, line = getLine(cm.doc, cur.line).text
      if (line) {
        if (cur.ch == line.length) { cur = new Pos(cur.line, cur.ch - 1) }
        if (cur.ch > 0) {
          cur = new Pos(cur.line, cur.ch + 1)
          cm.replaceRange(line.charAt(cur.ch - 1) + line.charAt(cur.ch - 2),
                          Pos(cur.line, cur.ch - 2), cur, "+transpose")
        } else if (cur.line > cm.doc.first) {
          var prev = getLine(cm.doc, cur.line - 1).text
          if (prev) {
            cur = new Pos(cur.line, 1)
            cm.replaceRange(line.charAt(0) + cm.doc.lineSeparator() +
                            prev.charAt(prev.length - 1),
                            Pos(cur.line - 1, prev.length - 1), cur, "+transpose")
          }
        }
      }
      newSel.push(new Range(cur, cur))
    }
    cm.setSelections(newSel)
  }); },
  newlineAndIndent: function (cm) { return runInOp(cm, function () {
    var sels = cm.listSelections()
    for (var i = sels.length - 1; i >= 0; i--)
      { cm.replaceRange(cm.doc.lineSeparator(), sels[i].anchor, sels[i].head, "+input") }
    sels = cm.listSelections()
    for (var i$1 = 0; i$1 < sels.length; i$1++)
      { cm.indentLine(sels[i$1].from().line, null, true) }
    ensureCursorVisible(cm)
  }); },
  openLine: function (cm) { return cm.replaceSelection("\n", "start"); },
  toggleOverwrite: function (cm) { return cm.toggleOverwrite(); }
}


function lineStart(cm, lineN) {
  var line = getLine(cm.doc, lineN)
  var visual = visualLine(line)
  if (visual != line) { lineN = lineNo(visual) }
  return endOfLine(true, cm, visual, lineN, 1)
}
function lineEnd(cm, lineN) {
  var line = getLine(cm.doc, lineN)
  var visual = visualLineEnd(line)
  if (visual != line) { lineN = lineNo(visual) }
  return endOfLine(true, cm, line, lineN, -1)
}
function lineStartSmart(cm, pos) {
  var start = lineStart(cm, pos.line)
  var line = getLine(cm.doc, start.line)
  var order = getOrder(line, cm.doc.direction)
  if (!order || order[0].level == 0) {
    var firstNonWS = Math.max(0, line.text.search(/\S/))
    var inWS = pos.line == start.line && pos.ch <= firstNonWS && pos.ch
    return Pos(start.line, inWS ? 0 : firstNonWS, start.sticky)
  }
  return start
}

// Run a handler that was bound to a key.
function doHandleBinding(cm, bound, dropShift) {
  if (typeof bound == "string") {
    bound = commands[bound]
    if (!bound) { return false }
  }
  // Ensure previous input has been read, so that the handler sees a
  // consistent view of the document
  cm.display.input.ensurePolled()
  var prevShift = cm.display.shift, done = false
  try {
    if (cm.isReadOnly()) { cm.state.suppressEdits = true }
    if (dropShift) { cm.display.shift = false }
    done = bound(cm) != Pass
  } finally {
    cm.display.shift = prevShift
    cm.state.suppressEdits = false
  }
  return done
}

function lookupKeyForEditor(cm, name, handle) {
  for (var i = 0; i < cm.state.keyMaps.length; i++) {
    var result = lookupKey(name, cm.state.keyMaps[i], handle, cm)
    if (result) { return result }
  }
  return (cm.options.extraKeys && lookupKey(name, cm.options.extraKeys, handle, cm))
    || lookupKey(name, cm.options.keyMap, handle, cm)
}

// Note that, despite the name, this function is also used to check
// for bound mouse clicks.

var stopSeq = new Delayed

function dispatchKey(cm, name, e, handle) {
  var seq = cm.state.keySeq
  if (seq) {
    if (isModifierKey(name)) { return "handled" }
    if (/\'$/.test(name))
      { cm.state.keySeq = null }
    else
      { stopSeq.set(50, function () {
        if (cm.state.keySeq == seq) {
          cm.state.keySeq = null
          cm.display.input.reset()
        }
      }) }
    if (dispatchKeyInner(cm, seq + " " + name, e, handle)) { return true }
  }
  return dispatchKeyInner(cm, name, e, handle)
}

function dispatchKeyInner(cm, name, e, handle) {
  var result = lookupKeyForEditor(cm, name, handle)

  if (result == "multi")
    { cm.state.keySeq = name }
  if (result == "handled")
    { signalLater(cm, "keyHandled", cm, name, e) }

  if (result == "handled" || result == "multi") {
    e_preventDefault(e)
    restartBlink(cm)
  }

  return !!result
}

// Handle a key from the keydown event.
function handleKeyBinding(cm, e) {
  var name = keyName(e, true)
  if (!name) { return false }

  if (e.shiftKey && !cm.state.keySeq) {
    // First try to resolve full name (including 'Shift-'). Failing
    // that, see if there is a cursor-motion command (starting with
    // 'go') bound to the keyname without 'Shift-'.
    return dispatchKey(cm, "Shift-" + name, e, function (b) { return doHandleBinding(cm, b, true); })
        || dispatchKey(cm, name, e, function (b) {
             if (typeof b == "string" ? /^go[A-Z]/.test(b) : b.motion)
               { return doHandleBinding(cm, b) }
           })
  } else {
    return dispatchKey(cm, name, e, function (b) { return doHandleBinding(cm, b); })
  }
}

// Handle a key from the keypress event
function handleCharBinding(cm, e, ch) {
  return dispatchKey(cm, "'" + ch + "'", e, function (b) { return doHandleBinding(cm, b, true); })
}

var lastStoppedKey = null
function onKeyDown(e) {
  var cm = this
  cm.curOp.focus = activeElt()
  if (signalDOMEvent(cm, e)) { return }
  // IE does strange things with escape.
  if (ie && ie_version < 11 && e.keyCode == 27) { e.returnValue = false }
  var code = e.keyCode
  cm.display.shift = code == 16 || e.shiftKey
  var handled = handleKeyBinding(cm, e)
  if (presto) {
    lastStoppedKey = handled ? code : null
    // Opera has no cut event... we try to at least catch the key combo
    if (!handled && code == 88 && !hasCopyEvent && (mac ? e.metaKey : e.ctrlKey))
      { cm.replaceSelection("", null, "cut") }
  }

  // Turn mouse into crosshair when Alt is held on Mac.
  if (code == 18 && !/\bCodeMirror-crosshair\b/.test(cm.display.lineDiv.className))
    { showCrossHair(cm) }
}

function showCrossHair(cm) {
  var lineDiv = cm.display.lineDiv
  addClass(lineDiv, "CodeMirror-crosshair")

  function up(e) {
    if (e.keyCode == 18 || !e.altKey) {
      rmClass(lineDiv, "CodeMirror-crosshair")
      off(document, "keyup", up)
      off(document, "mouseover", up)
    }
  }
  on(document, "keyup", up)
  on(document, "mouseover", up)
}

function onKeyUp(e) {
  if (e.keyCode == 16) { this.doc.sel.shift = false }
  signalDOMEvent(this, e)
}

function onKeyPress(e) {
  var cm = this
  if (eventInWidget(cm.display, e) || signalDOMEvent(cm, e) || e.ctrlKey && !e.altKey || mac && e.metaKey) { return }
  var keyCode = e.keyCode, charCode = e.charCode
  if (presto && keyCode == lastStoppedKey) {lastStoppedKey = null; e_preventDefault(e); return}
  if ((presto && (!e.which || e.which < 10)) && handleKeyBinding(cm, e)) { return }
  var ch = String.fromCharCode(charCode == null ? keyCode : charCode)
  // Some browsers fire keypress events for backspace
  if (ch == "\x08") { return }
  if (handleCharBinding(cm, e, ch)) { return }
  cm.display.input.onKeyPress(e)
}

var DOUBLECLICK_DELAY = 400

var PastClick = function(time, pos, button) {
  this.time = time
  this.pos = pos
  this.button = button
};

PastClick.prototype.compare = function (time, pos, button) {
  return this.time + DOUBLECLICK_DELAY > time &&
    cmp(pos, this.pos) == 0 && button == this.button
};

var lastClick;
var lastDoubleClick;
function clickRepeat(pos, button) {
  var now = +new Date
  if (lastDoubleClick && lastDoubleClick.compare(now, pos, button)) {
    lastClick = lastDoubleClick = null
    return "triple"
  } else if (lastClick && lastClick.compare(now, pos, button)) {
    lastDoubleClick = new PastClick(now, pos, button)
    lastClick = null
    return "double"
  } else {
    lastClick = new PastClick(now, pos, button)
    lastDoubleClick = null
    return "single"
  }
}

// A mouse down can be a single click, double click, triple click,
// start of selection drag, start of text drag, new cursor
// (ctrl-click), rectangle drag (alt-drag), or xwin
// middle-click-paste. Or it might be a click on something we should
// not interfere with, such as a scrollbar or widget.
function onMouseDown(e) {
  var cm = this, display = cm.display
  if (signalDOMEvent(cm, e) || display.activeTouch && display.input.supportsTouch()) { return }
  display.input.ensurePolled()
  display.shift = e.shiftKey

  if (eventInWidget(display, e)) {
    if (!webkit) {
      // Briefly turn off draggability, to allow widgets to do
      // normal dragging things.
      display.scroller.draggable = false
      setTimeout(function () { return display.scroller.draggable = true; }, 100)
    }
    return
  }
  var button = e_button(e)
  if (button == 3 && captureRightClick ? contextMenuInGutter(cm, e) : clickInGutter(cm, e)) { return }
  var pos = posFromMouse(cm, e), repeat = pos ? clickRepeat(pos, button) : "single"
  window.focus()

  // #3261: make sure, that we're not starting a second selection
  if (button == 1 && cm.state.selectingText)
    { cm.state.selectingText(e) }

  if (pos && handleMappedButton(cm, button, pos, repeat, e)) { return }

  if (button == 1) {
    if (pos) { leftButtonDown(cm, pos, repeat, e) }
    else if (e_target(e) == display.scroller) { e_preventDefault(e) }
  } else if (button == 2) {
    if (pos) { extendSelection(cm.doc, pos) }
    setTimeout(function () { return display.input.focus(); }, 20)
  } else if (button == 3) {
    if (captureRightClick) { onContextMenu(cm, e) }
    else { delayBlurEvent(cm) }
  }
}

function handleMappedButton(cm, button, pos, repeat, event) {
  var name = "Click"
  if (repeat == "double") { name = "Double" + name }
  else if (repeat == "triple") { name = "Triple" + name }
  name = (button == 1 ? "Left" : button == 2 ? "Middle" : "Right") + name

  return dispatchKey(cm,  addModifierNames(name, event), event, function (bound) {
    if (typeof bound == "string") { bound = commands[bound] }
    if (!bound) { return false }
    var done = false
    try {
      if (cm.isReadOnly()) { cm.state.suppressEdits = true }
      done = bound(cm, pos) != Pass
    } finally {
      cm.state.suppressEdits = false
    }
    return done
  })
}

function configureMouse(cm, repeat, event) {
  var option = cm.getOption("configureMouse")
  var value = option ? option(cm, repeat, event) : {}
  if (value.unit == null) {
    var rect = chromeOS ? event.shiftKey && event.metaKey : event.altKey
    value.unit = rect ? "rectangle" : repeat == "single" ? "char" : repeat == "double" ? "word" : "line"
  }
  if (value.extend == null || cm.doc.extend) { value.extend = cm.doc.extend || event.shiftKey }
  if (value.addNew == null) { value.addNew = mac ? event.metaKey : event.ctrlKey }
  if (value.moveOnDrag == null) { value.moveOnDrag = !(mac ? event.altKey : event.ctrlKey) }
  return value
}

function leftButtonDown(cm, pos, repeat, event) {
  if (ie) { setTimeout(bind(ensureFocus, cm), 0) }
  else { cm.curOp.focus = activeElt() }

  var behavior = configureMouse(cm, repeat, event)

  var sel = cm.doc.sel, contained
  if (cm.options.dragDrop && dragAndDrop && !cm.isReadOnly() &&
      repeat == "single" && (contained = sel.contains(pos)) > -1 &&
      (cmp((contained = sel.ranges[contained]).from(), pos) < 0 || pos.xRel > 0) &&
      (cmp(contained.to(), pos) > 0 || pos.xRel < 0))
    { leftButtonStartDrag(cm, event, pos, behavior) }
  else
    { leftButtonSelect(cm, event, pos, behavior) }
}

// Start a text drag. When it ends, see if any dragging actually
// happen, and treat as a click if it didn't.
function leftButtonStartDrag(cm, event, pos, behavior) {
  var display = cm.display, moved = false
  var dragEnd = operation(cm, function (e) {
    if (webkit) { display.scroller.draggable = false }
    cm.state.draggingText = false
    off(display.wrapper.ownerDocument, "mouseup", dragEnd)
    off(display.wrapper.ownerDocument, "mousemove", mouseMove)
    off(display.scroller, "dragstart", dragStart)
    off(display.scroller, "drop", dragEnd)
    if (!moved) {
      e_preventDefault(e)
      if (!behavior.addNew)
        { extendSelection(cm.doc, pos, null, null, behavior.extend) }
      // Work around unexplainable focus problem in IE9 (#2127) and Chrome (#3081)
      if (webkit || ie && ie_version == 9)
        { setTimeout(function () {display.wrapper.ownerDocument.body.focus(); display.input.focus()}, 20) }
      else
        { display.input.focus() }
    }
  })
  var mouseMove = function(e2) {
    moved = moved || Math.abs(event.clientX - e2.clientX) + Math.abs(event.clientY - e2.clientY) >= 10
  }
  var dragStart = function () { return moved = true; }
  // Let the drag handler handle this.
  if (webkit) { display.scroller.draggable = true }
  cm.state.draggingText = dragEnd
  dragEnd.copy = !behavior.moveOnDrag
  // IE's approach to draggable
  if (display.scroller.dragDrop) { display.scroller.dragDrop() }
  on(display.wrapper.ownerDocument, "mouseup", dragEnd)
  on(display.wrapper.ownerDocument, "mousemove", mouseMove)
  on(display.scroller, "dragstart", dragStart)
  on(display.scroller, "drop", dragEnd)

  delayBlurEvent(cm)
  setTimeout(function () { return display.input.focus(); }, 20)
}

function rangeForUnit(cm, pos, unit) {
  if (unit == "char") { return new Range(pos, pos) }
  if (unit == "word") { return cm.findWordAt(pos) }
  if (unit == "line") { return new Range(Pos(pos.line, 0), clipPos(cm.doc, Pos(pos.line + 1, 0))) }
  var result = unit(cm, pos)
  return new Range(result.from, result.to)
}

// Normal selection, as opposed to text dragging.
function leftButtonSelect(cm, event, start, behavior) {
  var display = cm.display, doc = cm.doc
  e_preventDefault(event)

  var ourRange, ourIndex, startSel = doc.sel, ranges = startSel.ranges
  if (behavior.addNew && !behavior.extend) {
    ourIndex = doc.sel.contains(start)
    if (ourIndex > -1)
      { ourRange = ranges[ourIndex] }
    else
      { ourRange = new Range(start, start) }
  } else {
    ourRange = doc.sel.primary()
    ourIndex = doc.sel.primIndex
  }

  if (behavior.unit == "rectangle") {
    if (!behavior.addNew) { ourRange = new Range(start, start) }
    start = posFromMouse(cm, event, true, true)
    ourIndex = -1
  } else {
    var range = rangeForUnit(cm, start, behavior.unit)
    if (behavior.extend)
      { ourRange = extendRange(ourRange, range.anchor, range.head, behavior.extend) }
    else
      { ourRange = range }
  }

  if (!behavior.addNew) {
    ourIndex = 0
    setSelection(doc, new Selection([ourRange], 0), sel_mouse)
    startSel = doc.sel
  } else if (ourIndex == -1) {
    ourIndex = ranges.length
    setSelection(doc, normalizeSelection(ranges.concat([ourRange]), ourIndex),
                 {scroll: false, origin: "*mouse"})
  } else if (ranges.length > 1 && ranges[ourIndex].empty() && behavior.unit == "char" && !behavior.extend) {
    setSelection(doc, normalizeSelection(ranges.slice(0, ourIndex).concat(ranges.slice(ourIndex + 1)), 0),
                 {scroll: false, origin: "*mouse"})
    startSel = doc.sel
  } else {
    replaceOneSelection(doc, ourIndex, ourRange, sel_mouse)
  }

  var lastPos = start
  function extendTo(pos) {
    if (cmp(lastPos, pos) == 0) { return }
    lastPos = pos

    if (behavior.unit == "rectangle") {
      var ranges = [], tabSize = cm.options.tabSize
      var startCol = countColumn(getLine(doc, start.line).text, start.ch, tabSize)
      var posCol = countColumn(getLine(doc, pos.line).text, pos.ch, tabSize)
      var left = Math.min(startCol, posCol), right = Math.max(startCol, posCol)
      for (var line = Math.min(start.line, pos.line), end = Math.min(cm.lastLine(), Math.max(start.line, pos.line));
           line <= end; line++) {
        var text = getLine(doc, line).text, leftPos = findColumn(text, left, tabSize)
        if (left == right)
          { ranges.push(new Range(Pos(line, leftPos), Pos(line, leftPos))) }
        else if (text.length > leftPos)
          { ranges.push(new Range(Pos(line, leftPos), Pos(line, findColumn(text, right, tabSize)))) }
      }
      if (!ranges.length) { ranges.push(new Range(start, start)) }
      setSelection(doc, normalizeSelection(startSel.ranges.slice(0, ourIndex).concat(ranges), ourIndex),
                   {origin: "*mouse", scroll: false})
      cm.scrollIntoView(pos)
    } else {
      var oldRange = ourRange
      var range = rangeForUnit(cm, pos, behavior.unit)
      var anchor = oldRange.anchor, head
      if (cmp(range.anchor, anchor) > 0) {
        head = range.head
        anchor = minPos(oldRange.from(), range.anchor)
      } else {
        head = range.anchor
        anchor = maxPos(oldRange.to(), range.head)
      }
      var ranges$1 = startSel.ranges.slice(0)
      ranges$1[ourIndex] = bidiSimplify(cm, new Range(clipPos(doc, anchor), head))
      setSelection(doc, normalizeSelection(ranges$1, ourIndex), sel_mouse)
    }
  }

  var editorSize = display.wrapper.getBoundingClientRect()
  // Used to ensure timeout re-tries don't fire when another extend
  // happened in the meantime (clearTimeout isn't reliable -- at
  // least on Chrome, the timeouts still happen even when cleared,
  // if the clear happens after their scheduled firing time).
  var counter = 0

  function extend(e) {
    var curCount = ++counter
    var cur = posFromMouse(cm, e, true, behavior.unit == "rectangle")
    if (!cur) { return }
    if (cmp(cur, lastPos) != 0) {
      cm.curOp.focus = activeElt()
      extendTo(cur)
      var visible = visibleLines(display, doc)
      if (cur.line >= visible.to || cur.line < visible.from)
        { setTimeout(operation(cm, function () {if (counter == curCount) { extend(e) }}), 150) }
    } else {
      var outside = e.clientY < editorSize.top ? -20 : e.clientY > editorSize.bottom ? 20 : 0
      if (outside) { setTimeout(operation(cm, function () {
        if (counter != curCount) { return }
        display.scroller.scrollTop += outside
        extend(e)
      }), 50) }
    }
  }

  function done(e) {
    cm.state.selectingText = false
    counter = Infinity
    e_preventDefault(e)
    display.input.focus()
    off(display.wrapper.ownerDocument, "mousemove", move)
    off(display.wrapper.ownerDocument, "mouseup", up)
    doc.history.lastSelOrigin = null
  }

  var move = operation(cm, function (e) {
    if (e.buttons === 0 || !e_button(e)) { done(e) }
    else { extend(e) }
  })
  var up = operation(cm, done)
  cm.state.selectingText = up
  on(display.wrapper.ownerDocument, "mousemove", move)
  on(display.wrapper.ownerDocument, "mouseup", up)
}

// Used when mouse-selecting to adjust the anchor to the proper side
// of a bidi jump depending on the visual position of the head.
function bidiSimplify(cm, range) {
  var anchor = range.anchor;
  var head = range.head;
  var anchorLine = getLine(cm.doc, anchor.line)
  if (cmp(anchor, head) == 0 && anchor.sticky == head.sticky) { return range }
  var order = getOrder(anchorLine)
  if (!order) { return range }
  var index = getBidiPartAt(order, anchor.ch, anchor.sticky), part = order[index]
  if (part.from != anchor.ch && part.to != anchor.ch) { return range }
  var boundary = index + ((part.from == anchor.ch) == (part.level != 1) ? 0 : 1)
  if (boundary == 0 || boundary == order.length) { return range }

  // Compute the relative visual position of the head compared to the
  // anchor (<0 is to the left, >0 to the right)
  var leftSide
  if (head.line != anchor.line) {
    leftSide = (head.line - anchor.line) * (cm.doc.direction == "ltr" ? 1 : -1) > 0
  } else {
    var headIndex = getBidiPartAt(order, head.ch, head.sticky)
    var dir = headIndex - index || (head.ch - anchor.ch) * (part.level == 1 ? -1 : 1)
    if (headIndex == boundary - 1 || headIndex == boundary)
      { leftSide = dir < 0 }
    else
      { leftSide = dir > 0 }
  }

  var usePart = order[boundary + (leftSide ? -1 : 0)]
  var from = leftSide == (usePart.level == 1)
  var ch = from ? usePart.from : usePart.to, sticky = from ? "after" : "before"
  return anchor.ch == ch && anchor.sticky == sticky ? range : new Range(new Pos(anchor.line, ch, sticky), head)
}


// Determines whether an event happened in the gutter, and fires the
// handlers for the corresponding event.
function gutterEvent(cm, e, type, prevent) {
  var mX, mY
  if (e.touches) {
    mX = e.touches[0].clientX
    mY = e.touches[0].clientY
  } else {
    try { mX = e.clientX; mY = e.clientY }
    catch(e) { return false }
  }
  if (mX >= Math.floor(cm.display.gutters.getBoundingClientRect().right)) { return false }
  if (prevent) { e_preventDefault(e) }

  var display = cm.display
  var lineBox = display.lineDiv.getBoundingClientRect()

  if (mY > lineBox.bottom || !hasHandler(cm, type)) { return e_defaultPrevented(e) }
  mY -= lineBox.top - display.viewOffset

  for (var i = 0; i < cm.options.gutters.length; ++i) {
    var g = display.gutters.childNodes[i]
    if (g && g.getBoundingClientRect().right >= mX) {
      var line = lineAtHeight(cm.doc, mY)
      var gutter = cm.options.gutters[i]
      signal(cm, type, cm, line, gutter, e)
      return e_defaultPrevented(e)
    }
  }
}

function clickInGutter(cm, e) {
  return gutterEvent(cm, e, "gutterClick", true)
}

// CONTEXT MENU HANDLING

// To make the context menu work, we need to briefly unhide the
// textarea (making it as unobtrusive as possible) to let the
// right-click take effect on it.
function onContextMenu(cm, e) {
  if (eventInWidget(cm.display, e) || contextMenuInGutter(cm, e)) { return }
  if (signalDOMEvent(cm, e, "contextmenu")) { return }
  cm.display.input.onContextMenu(e)
}

function contextMenuInGutter(cm, e) {
  if (!hasHandler(cm, "gutterContextMenu")) { return false }
  return gutterEvent(cm, e, "gutterContextMenu", false)
}

function themeChanged(cm) {
  cm.display.wrapper.className = cm.display.wrapper.className.replace(/\s*cm-s-\S+/g, "") +
    cm.options.theme.replace(/(^|\s)\s*/g, " cm-s-")
  clearCaches(cm)
}

var Init = {toString: function(){return "CodeMirror.Init"}}

var defaults = {}
var optionHandlers = {}

function defineOptions(CodeMirror) {
  var optionHandlers = CodeMirror.optionHandlers

  function option(name, deflt, handle, notOnInit) {
    CodeMirror.defaults[name] = deflt
    if (handle) { optionHandlers[name] =
      notOnInit ? function (cm, val, old) {if (old != Init) { handle(cm, val, old) }} : handle }
  }

  CodeMirror.defineOption = option

  // Passed to option handlers when there is no old value.
  CodeMirror.Init = Init

  // These two are, on init, called from the constructor because they
  // have to be initialized before the editor can start at all.
  option("value", "", function (cm, val) { return cm.setValue(val); }, true)
  option("mode", null, function (cm, val) {
    cm.doc.modeOption = val
    loadMode(cm)
  }, true)

  option("indentUnit", 2, loadMode, true)
  option("indentWithTabs", false)
  option("smartIndent", true)
  option("tabSize", 4, function (cm) {
    resetModeState(cm)
    clearCaches(cm)
    regChange(cm)
  }, true)

  option("lineSeparator", null, function (cm, val) {
    cm.doc.lineSep = val
    if (!val) { return }
    var newBreaks = [], lineNo = cm.doc.first
    cm.doc.iter(function (line) {
      for (var pos = 0;;) {
        var found = line.text.indexOf(val, pos)
        if (found == -1) { break }
        pos = found + val.length
        newBreaks.push(Pos(lineNo, found))
      }
      lineNo++
    })
    for (var i = newBreaks.length - 1; i >= 0; i--)
      { replaceRange(cm.doc, val, newBreaks[i], Pos(newBreaks[i].line, newBreaks[i].ch + val.length)) }
  })
  option("specialChars", /[\u0000-\u001f\u007f-\u009f\u00ad\u061c\u200b-\u200f\u2028\u2029\ufeff]/g, function (cm, val, old) {
    cm.state.specialChars = new RegExp(val.source + (val.test("\t") ? "" : "|\t"), "g")
    if (old != Init) { cm.refresh() }
  })
  option("specialCharPlaceholder", defaultSpecialCharPlaceholder, function (cm) { return cm.refresh(); }, true)
  option("electricChars", true)
  option("inputStyle", mobile ? "contenteditable" : "textarea", function () {
    throw new Error("inputStyle can not (yet) be changed in a running editor") // FIXME
  }, true)
  option("spellcheck", false, function (cm, val) { return cm.getInputField().spellcheck = val; }, true)
  option("rtlMoveVisually", !windows)
  option("wholeLineUpdateBefore", true)

  option("theme", "default", function (cm) {
    themeChanged(cm)
    guttersChanged(cm)
  }, true)
  option("keyMap", "default", function (cm, val, old) {
    var next = getKeyMap(val)
    var prev = old != Init && getKeyMap(old)
    if (prev && prev.detach) { prev.detach(cm, next) }
    if (next.attach) { next.attach(cm, prev || null) }
  })
  option("extraKeys", null)
  option("configureMouse", null)

  option("lineWrapping", false, wrappingChanged, true)
  option("gutters", [], function (cm) {
    setGuttersForLineNumbers(cm.options)
    guttersChanged(cm)
  }, true)
  option("fixedGutter", true, function (cm, val) {
    cm.display.gutters.style.left = val ? compensateForHScroll(cm.display) + "px" : "0"
    cm.refresh()
  }, true)
  option("coverGutterNextToScrollbar", false, function (cm) { return updateScrollbars(cm); }, true)
  option("scrollbarStyle", "native", function (cm) {
    initScrollbars(cm)
    updateScrollbars(cm)
    cm.display.scrollbars.setScrollTop(cm.doc.scrollTop)
    cm.display.scrollbars.setScrollLeft(cm.doc.scrollLeft)
  }, true)
  option("lineNumbers", false, function (cm) {
    setGuttersForLineNumbers(cm.options)
    guttersChanged(cm)
  }, true)
  option("firstLineNumber", 1, guttersChanged, true)
  option("lineNumberFormatter", function (integer) { return integer; }, guttersChanged, true)
  option("showCursorWhenSelecting", false, updateSelection, true)

  option("resetSelectionOnContextMenu", true)
  option("lineWiseCopyCut", true)
  option("pasteLinesPerSelection", true)

  option("readOnly", false, function (cm, val) {
    if (val == "nocursor") {
      onBlur(cm)
      cm.display.input.blur()
    }
    cm.display.input.readOnlyChanged(val)
  })
  option("disableInput", false, function (cm, val) {if (!val) { cm.display.input.reset() }}, true)
  option("dragDrop", true, dragDropChanged)
  option("allowDropFileTypes", null)

  option("cursorBlinkRate", 530)
  option("cursorScrollMargin", 0)
  option("cursorHeight", 1, updateSelection, true)
  option("singleCursorHeightPerLine", true, updateSelection, true)
  option("workTime", 100)
  option("workDelay", 100)
  option("flattenSpans", true, resetModeState, true)
  option("addModeClass", false, resetModeState, true)
  option("pollInterval", 100)
  option("undoDepth", 200, function (cm, val) { return cm.doc.history.undoDepth = val; })
  option("historyEventDelay", 1250)
  option("viewportMargin", 10, function (cm) { return cm.refresh(); }, true)
  option("maxHighlightLength", 10000, resetModeState, true)
  option("moveInputWithCursor", true, function (cm, val) {
    if (!val) { cm.display.input.resetPosition() }
  })

  option("tabindex", null, function (cm, val) { return cm.display.input.getField().tabIndex = val || ""; })
  option("autofocus", null)
  option("direction", "ltr", function (cm, val) { return cm.doc.setDirection(val); }, true)
  option("phrases", null)
}

function guttersChanged(cm) {
  updateGutters(cm)
  regChange(cm)
  alignHorizontally(cm)
}

function dragDropChanged(cm, value, old) {
  var wasOn = old && old != Init
  if (!value != !wasOn) {
    var funcs = cm.display.dragFunctions
    var toggle = value ? on : off
    toggle(cm.display.scroller, "dragstart", funcs.start)
    toggle(cm.display.scroller, "dragenter", funcs.enter)
    toggle(cm.display.scroller, "dragover", funcs.over)
    toggle(cm.display.scroller, "dragleave", funcs.leave)
    toggle(cm.display.scroller, "drop", funcs.drop)
  }
}

function wrappingChanged(cm) {
  if (cm.options.lineWrapping) {
    addClass(cm.display.wrapper, "CodeMirror-wrap")
    cm.display.sizer.style.minWidth = ""
    cm.display.sizerWidth = null
  } else {
    rmClass(cm.display.wrapper, "CodeMirror-wrap")
    findMaxLine(cm)
  }
  estimateLineHeights(cm)
  regChange(cm)
  clearCaches(cm)
  setTimeout(function () { return updateScrollbars(cm); }, 100)
}

// A CodeMirror instance represents an editor. This is the object
// that user code is usually dealing with.

function CodeMirror(place, options) {
  var this$1 = this;

  if (!(this instanceof CodeMirror)) { return new CodeMirror(place, options) }

  this.options = options = options ? copyObj(options) : {}
  // Determine effective options based on given values and defaults.
  copyObj(defaults, options, false)
  setGuttersForLineNumbers(options)

  var doc = options.value
  if (typeof doc == "string") { doc = new Doc(doc, options.mode, null, options.lineSeparator, options.direction) }
  else if (options.mode) { doc.modeOption = options.mode }
  this.doc = doc

  var input = new CodeMirror.inputStyles[options.inputStyle](this)
  var display = this.display = new Display(place, doc, input)
  display.wrapper.CodeMirror = this
  updateGutters(this)
  themeChanged(this)
  if (options.lineWrapping)
    { this.display.wrapper.className += " CodeMirror-wrap" }
  initScrollbars(this)

  this.state = {
    keyMaps: [],  // stores maps added by addKeyMap
    overlays: [], // highlighting overlays, as added by addOverlay
    modeGen: 0,   // bumped when mode/overlay changes, used to invalidate highlighting info
    overwrite: false,
    delayingBlurEvent: false,
    focused: false,
    suppressEdits: false, // used to disable editing during key handlers when in readOnly mode
    pasteIncoming: false, cutIncoming: false, // help recognize paste/cut edits in input.poll
    selectingText: false,
    draggingText: false,
    highlight: new Delayed(), // stores highlight worker timeout
    keySeq: null,  // Unfinished key sequence
    specialChars: null
  }

  if (options.autofocus && !mobile) { display.input.focus() }

  // Override magic textarea content restore that IE sometimes does
  // on our hidden textarea on reload
  if (ie && ie_version < 11) { setTimeout(function () { return this$1.display.input.reset(true); }, 20) }

  registerEventHandlers(this)
  ensureGlobalHandlers()

  startOperation(this)
  this.curOp.forceUpdate = true
  attachDoc(this, doc)

  if ((options.autofocus && !mobile) || this.hasFocus())
    { setTimeout(bind(onFocus, this), 20) }
  else
    { onBlur(this) }

  for (var opt in optionHandlers) { if (optionHandlers.hasOwnProperty(opt))
    { optionHandlers[opt](this$1, options[opt], Init) } }
  maybeUpdateLineNumberWidth(this)
  if (options.finishInit) { options.finishInit(this) }
  for (var i = 0; i < initHooks.length; ++i) { initHooks[i](this$1) }
  endOperation(this)
  // Suppress optimizelegibility in Webkit, since it breaks text
  // measuring on line wrapping boundaries.
  if (webkit && options.lineWrapping &&
      getComputedStyle(display.lineDiv).textRendering == "optimizelegibility")
    { display.lineDiv.style.textRendering = "auto" }
}

// The default configuration options.
CodeMirror.defaults = defaults
// Functions to run when options are changed.
CodeMirror.optionHandlers = optionHandlers

// Attach the necessary event handlers when initializing the editor
function registerEventHandlers(cm) {
  var d = cm.display
  on(d.scroller, "mousedown", operation(cm, onMouseDown))
  // Older IE's will not fire a second mousedown for a double click
  if (ie && ie_version < 11)
    { on(d.scroller, "dblclick", operation(cm, function (e) {
      if (signalDOMEvent(cm, e)) { return }
      var pos = posFromMouse(cm, e)
      if (!pos || clickInGutter(cm, e) || eventInWidget(cm.display, e)) { return }
      e_preventDefault(e)
      var word = cm.findWordAt(pos)
      extendSelection(cm.doc, word.anchor, word.head)
    })) }
  else
    { on(d.scroller, "dblclick", function (e) { return signalDOMEvent(cm, e) || e_preventDefault(e); }) }
  // Some browsers fire contextmenu *after* opening the menu, at
  // which point we can't mess with it anymore. Context menu is
  // handled in onMouseDown for these browsers.
  if (!captureRightClick) { on(d.scroller, "contextmenu", function (e) { return onContextMenu(cm, e); }) }

  // Used to suppress mouse event handling when a touch happens
  var touchFinished, prevTouch = {end: 0}
  function finishTouch() {
    if (d.activeTouch) {
      touchFinished = setTimeout(function () { return d.activeTouch = null; }, 1000)
      prevTouch = d.activeTouch
      prevTouch.end = +new Date
    }
  }
  function isMouseLikeTouchEvent(e) {
    if (e.touches.length != 1) { return false }
    var touch = e.touches[0]
    return touch.radiusX <= 1 && touch.radiusY <= 1
  }
  function farAway(touch, other) {
    if (other.left == null) { return true }
    var dx = other.left - touch.left, dy = other.top - touch.top
    return dx * dx + dy * dy > 20 * 20
  }
  on(d.scroller, "touchstart", function (e) {
    if (!signalDOMEvent(cm, e) && !isMouseLikeTouchEvent(e) && !clickInGutter(cm, e)) {
      d.input.ensurePolled()
      clearTimeout(touchFinished)
      var now = +new Date
      d.activeTouch = {start: now, moved: false,
                       prev: now - prevTouch.end <= 300 ? prevTouch : null}
      if (e.touches.length == 1) {
        d.activeTouch.left = e.touches[0].pageX
        d.activeTouch.top = e.touches[0].pageY
      }
    }
  })
  on(d.scroller, "touchmove", function () {
    if (d.activeTouch) { d.activeTouch.moved = true }
  })
  on(d.scroller, "touchend", function (e) {
    var touch = d.activeTouch
    if (touch && !eventInWidget(d, e) && touch.left != null &&
        !touch.moved && new Date - touch.start < 300) {
      var pos = cm.coordsChar(d.activeTouch, "page"), range
      if (!touch.prev || farAway(touch, touch.prev)) // Single tap
        { range = new Range(pos, pos) }
      else if (!touch.prev.prev || farAway(touch, touch.prev.prev)) // Double tap
        { range = cm.findWordAt(pos) }
      else // Triple tap
        { range = new Range(Pos(pos.line, 0), clipPos(cm.doc, Pos(pos.line + 1, 0))) }
      cm.setSelection(range.anchor, range.head)
      cm.focus()
      e_preventDefault(e)
    }
    finishTouch()
  })
  on(d.scroller, "touchcancel", finishTouch)

  // Sync scrolling between fake scrollbars and real scrollable
  // area, ensure viewport is updated when scrolling.
  on(d.scroller, "scroll", function () {
    if (d.scroller.clientHeight) {
      updateScrollTop(cm, d.scroller.scrollTop)
      setScrollLeft(cm, d.scroller.scrollLeft, true)
      signal(cm, "scroll", cm)
    }
  })

  // Listen to wheel events in order to try and update the viewport on time.
  on(d.scroller, "mousewheel", function (e) { return onScrollWheel(cm, e); })
  on(d.scroller, "DOMMouseScroll", function (e) { return onScrollWheel(cm, e); })

  // Prevent wrapper from ever scrolling
  on(d.wrapper, "scroll", function () { return d.wrapper.scrollTop = d.wrapper.scrollLeft = 0; })

  d.dragFunctions = {
    enter: function (e) {if (!signalDOMEvent(cm, e)) { e_stop(e) }},
    over: function (e) {if (!signalDOMEvent(cm, e)) { onDragOver(cm, e); e_stop(e) }},
    start: function (e) { return onDragStart(cm, e); },
    drop: operation(cm, onDrop),
    leave: function (e) {if (!signalDOMEvent(cm, e)) { clearDragCursor(cm) }}
  }

  var inp = d.input.getField()
  on(inp, "keyup", function (e) { return onKeyUp.call(cm, e); })
  on(inp, "keydown", operation(cm, onKeyDown))
  on(inp, "keypress", operation(cm, onKeyPress))
  on(inp, "focus", function (e) { return onFocus(cm, e); })
  on(inp, "blur", function (e) { return onBlur(cm, e); })
}

var initHooks = []
CodeMirror.defineInitHook = function (f) { return initHooks.push(f); }

// Indent the given line. The how parameter can be "smart",
// "add"/null, "subtract", or "prev". When aggressive is false
// (typically set to true for forced single-line indents), empty
// lines are not indented, and places where the mode returns Pass
// are left alone.
function indentLine(cm, n, how, aggressive) {
  var doc = cm.doc, state
  if (how == null) { how = "add" }
  if (how == "smart") {
    // Fall back to "prev" when the mode doesn't have an indentation
    // method.
    if (!doc.mode.indent) { how = "prev" }
    else { state = getContextBefore(cm, n).state }
  }

  var tabSize = cm.options.tabSize
  var line = getLine(doc, n), curSpace = countColumn(line.text, null, tabSize)
  if (line.stateAfter) { line.stateAfter = null }
  var curSpaceString = line.text.match(/^\s*/)[0], indentation
  if (!aggressive && !/\S/.test(line.text)) {
    indentation = 0
    how = "not"
  } else if (how == "smart") {
    indentation = doc.mode.indent(state, line.text.slice(curSpaceString.length), line.text)
    if (indentation == Pass || indentation > 150) {
      if (!aggressive) { return }
      how = "prev"
    }
  }
  if (how == "prev") {
    if (n > doc.first) { indentation = countColumn(getLine(doc, n-1).text, null, tabSize) }
    else { indentation = 0 }
  } else if (how == "add") {
    indentation = curSpace + cm.options.indentUnit
  } else if (how == "subtract") {
    indentation = curSpace - cm.options.indentUnit
  } else if (typeof how == "number") {
    indentation = curSpace + how
  }
  indentation = Math.max(0, indentation)

  var indentString = "", pos = 0
  if (cm.options.indentWithTabs)
    { for (var i = Math.floor(indentation / tabSize); i; --i) {pos += tabSize; indentString += "\t"} }
  if (pos < indentation) { indentString += spaceStr(indentation - pos) }

  if (indentString != curSpaceString) {
    replaceRange(doc, indentString, Pos(n, 0), Pos(n, curSpaceString.length), "+input")
    line.stateAfter = null
    return true
  } else {
    // Ensure that, if the cursor was in the whitespace at the start
    // of the line, it is moved to the end of that space.
    for (var i$1 = 0; i$1 < doc.sel.ranges.length; i$1++) {
      var range = doc.sel.ranges[i$1]
      if (range.head.line == n && range.head.ch < curSpaceString.length) {
        var pos$1 = Pos(n, curSpaceString.length)
        replaceOneSelection(doc, i$1, new Range(pos$1, pos$1))
        break
      }
    }
  }
}

// This will be set to a {lineWise: bool, text: [string]} object, so
// that, when pasting, we know what kind of selections the copied
// text was made out of.
var lastCopied = null

function setLastCopied(newLastCopied) {
  lastCopied = newLastCopied
}

function applyTextInput(cm, inserted, deleted, sel, origin) {
  var doc = cm.doc
  cm.display.shift = false
  if (!sel) { sel = doc.sel }

  var paste = cm.state.pasteIncoming || origin == "paste"
  var textLines = splitLinesAuto(inserted), multiPaste = null
  // When pasting N lines into N selections, insert one line per selection
  if (paste && sel.ranges.length > 1) {
    if (lastCopied && lastCopied.text.join("\n") == inserted) {
      if (sel.ranges.length % lastCopied.text.length == 0) {
        multiPaste = []
        for (var i = 0; i < lastCopied.text.length; i++)
          { multiPaste.push(doc.splitLines(lastCopied.text[i])) }
      }
    } else if (textLines.length == sel.ranges.length && cm.options.pasteLinesPerSelection) {
      multiPaste = map(textLines, function (l) { return [l]; })
    }
  }

  var updateInput
  // Normal behavior is to insert the new text into every selection
  for (var i$1 = sel.ranges.length - 1; i$1 >= 0; i$1--) {
    var range = sel.ranges[i$1]
    var from = range.from(), to = range.to()
    if (range.empty()) {
      if (deleted && deleted > 0) // Handle deletion
        { from = Pos(from.line, from.ch - deleted) }
      else if (cm.state.overwrite && !paste) // Handle overwrite
        { to = Pos(to.line, Math.min(getLine(doc, to.line).text.length, to.ch + lst(textLines).length)) }
      else if (lastCopied && lastCopied.lineWise && lastCopied.text.join("\n") == inserted)
        { from = to = Pos(from.line, 0) }
    }
    updateInput = cm.curOp.updateInput
    var changeEvent = {from: from, to: to, text: multiPaste ? multiPaste[i$1 % multiPaste.length] : textLines,
                       origin: origin || (paste ? "paste" : cm.state.cutIncoming ? "cut" : "+input")}
    makeChange(cm.doc, changeEvent)
    signalLater(cm, "inputRead", cm, changeEvent)
  }
  if (inserted && !paste)
    { triggerElectric(cm, inserted) }

  ensureCursorVisible(cm)
  cm.curOp.updateInput = updateInput
  cm.curOp.typing = true
  cm.state.pasteIncoming = cm.state.cutIncoming = false
}

function handlePaste(e, cm) {
  var pasted = e.clipboardData && e.clipboardData.getData("Text")
  if (pasted) {
    e.preventDefault()
    if (!cm.isReadOnly() && !cm.options.disableInput)
      { runInOp(cm, function () { return applyTextInput(cm, pasted, 0, null, "paste"); }) }
    return true
  }
}

function triggerElectric(cm, inserted) {
  // When an 'electric' character is inserted, immediately trigger a reindent
  if (!cm.options.electricChars || !cm.options.smartIndent) { return }
  var sel = cm.doc.sel

  for (var i = sel.ranges.length - 1; i >= 0; i--) {
    var range = sel.ranges[i]
    if (range.head.ch > 100 || (i && sel.ranges[i - 1].head.line == range.head.line)) { continue }
    var mode = cm.getModeAt(range.head)
    var indented = false
    if (mode.electricChars) {
      for (var j = 0; j < mode.electricChars.length; j++)
        { if (inserted.indexOf(mode.electricChars.charAt(j)) > -1) {
          indented = indentLine(cm, range.head.line, "smart")
          break
        } }
    } else if (mode.electricInput) {
      if (mode.electricInput.test(getLine(cm.doc, range.head.line).text.slice(0, range.head.ch)))
        { indented = indentLine(cm, range.head.line, "smart") }
    }
    if (indented) { signalLater(cm, "electricInput", cm, range.head.line) }
  }
}

function copyableRanges(cm) {
  var text = [], ranges = []
  for (var i = 0; i < cm.doc.sel.ranges.length; i++) {
    var line = cm.doc.sel.ranges[i].head.line
    var lineRange = {anchor: Pos(line, 0), head: Pos(line + 1, 0)}
    ranges.push(lineRange)
    text.push(cm.getRange(lineRange.anchor, lineRange.head))
  }
  return {text: text, ranges: ranges}
}

function disableBrowserMagic(field, spellcheck) {
  field.setAttribute("autocorrect", "off")
  field.setAttribute("autocapitalize", "off")
  field.setAttribute("spellcheck", !!spellcheck)
}

function hiddenTextarea() {
  var te = elt("textarea", null, null, "position: absolute; bottom: -1em; padding: 0; width: 1px; height: 1em; outline: none")
  var div = elt("div", [te], null, "overflow: hidden; position: relative; width: 3px; height: 0px;")
  // The textarea is kept positioned near the cursor to prevent the
  // fact that it'll be scrolled into view on input from scrolling
  // our fake cursor out of view. On webkit, when wrap=off, paste is
  // very slow. So make the area wide instead.
  if (webkit) { te.style.width = "1000px" }
  else { te.setAttribute("wrap", "off") }
  // If border: 0; -- iOS fails to open keyboard (issue #1287)
  if (ios) { te.style.border = "1px solid black" }
  disableBrowserMagic(te)
  return div
}

// The publicly visible API. Note that methodOp(f) means
// 'wrap f in an operation, performed on its `this` parameter'.

// This is not the complete set of editor methods. Most of the
// methods defined on the Doc type are also injected into
// CodeMirror.prototype, for backwards compatibility and
// convenience.

function addEditorMethods(CodeMirror) {
  var optionHandlers = CodeMirror.optionHandlers

  var helpers = CodeMirror.helpers = {}

  CodeMirror.prototype = {
    constructor: CodeMirror,
    focus: function(){window.focus(); this.display.input.focus()},

    setOption: function(option, value) {
      var options = this.options, old = options[option]
      if (options[option] == value && option != "mode") { return }
      options[option] = value
      if (optionHandlers.hasOwnProperty(option))
        { operation(this, optionHandlers[option])(this, value, old) }
      signal(this, "optionChange", this, option)
    },

    getOption: function(option) {return this.options[option]},
    getDoc: function() {return this.doc},

    addKeyMap: function(map, bottom) {
      this.state.keyMaps[bottom ? "push" : "unshift"](getKeyMap(map))
    },
    removeKeyMap: function(map) {
      var maps = this.state.keyMaps
      for (var i = 0; i < maps.length; ++i)
        { if (maps[i] == map || maps[i].name == map) {
          maps.splice(i, 1)
          return true
        } }
    },

    addOverlay: methodOp(function(spec, options) {
      var mode = spec.token ? spec : CodeMirror.getMode(this.options, spec)
      if (mode.startState) { throw new Error("Overlays may not be stateful.") }
      insertSorted(this.state.overlays,
                   {mode: mode, modeSpec: spec, opaque: options && options.opaque,
                    priority: (options && options.priority) || 0},
                   function (overlay) { return overlay.priority; })
      this.state.modeGen++
      regChange(this)
    }),
    removeOverlay: methodOp(function(spec) {
      var this$1 = this;

      var overlays = this.state.overlays
      for (var i = 0; i < overlays.length; ++i) {
        var cur = overlays[i].modeSpec
        if (cur == spec || typeof spec == "string" && cur.name == spec) {
          overlays.splice(i, 1)
          this$1.state.modeGen++
          regChange(this$1)
          return
        }
      }
    }),

    indentLine: methodOp(function(n, dir, aggressive) {
      if (typeof dir != "string" && typeof dir != "number") {
        if (dir == null) { dir = this.options.smartIndent ? "smart" : "prev" }
        else { dir = dir ? "add" : "subtract" }
      }
      if (isLine(this.doc, n)) { indentLine(this, n, dir, aggressive) }
    }),
    indentSelection: methodOp(function(how) {
      var this$1 = this;

      var ranges = this.doc.sel.ranges, end = -1
      for (var i = 0; i < ranges.length; i++) {
        var range = ranges[i]
        if (!range.empty()) {
          var from = range.from(), to = range.to()
          var start = Math.max(end, from.line)
          end = Math.min(this$1.lastLine(), to.line - (to.ch ? 0 : 1)) + 1
          for (var j = start; j < end; ++j)
            { indentLine(this$1, j, how) }
          var newRanges = this$1.doc.sel.ranges
          if (from.ch == 0 && ranges.length == newRanges.length && newRanges[i].from().ch > 0)
            { replaceOneSelection(this$1.doc, i, new Range(from, newRanges[i].to()), sel_dontScroll) }
        } else if (range.head.line > end) {
          indentLine(this$1, range.head.line, how, true)
          end = range.head.line
          if (i == this$1.doc.sel.primIndex) { ensureCursorVisible(this$1) }
        }
      }
    }),

    // Fetch the parser token for a given character. Useful for hacks
    // that want to inspect the mode state (say, for completion).
    getTokenAt: function(pos, precise) {
      return takeToken(this, pos, precise)
    },

    getLineTokens: function(line, precise) {
      return takeToken(this, Pos(line), precise, true)
    },

    getTokenTypeAt: function(pos) {
      pos = clipPos(this.doc, pos)
      var styles = getLineStyles(this, getLine(this.doc, pos.line))
      var before = 0, after = (styles.length - 1) / 2, ch = pos.ch
      var type
      if (ch == 0) { type = styles[2] }
      else { for (;;) {
        var mid = (before + after) >> 1
        if ((mid ? styles[mid * 2 - 1] : 0) >= ch) { after = mid }
        else if (styles[mid * 2 + 1] < ch) { before = mid + 1 }
        else { type = styles[mid * 2 + 2]; break }
      } }
      var cut = type ? type.indexOf("overlay ") : -1
      return cut < 0 ? type : cut == 0 ? null : type.slice(0, cut - 1)
    },

    getModeAt: function(pos) {
      var mode = this.doc.mode
      if (!mode.innerMode) { return mode }
      return CodeMirror.innerMode(mode, this.getTokenAt(pos).state).mode
    },

    getHelper: function(pos, type) {
      return this.getHelpers(pos, type)[0]
    },

    getHelpers: function(pos, type) {
      var this$1 = this;

      var found = []
      if (!helpers.hasOwnProperty(type)) { return found }
      var help = helpers[type], mode = this.getModeAt(pos)
      if (typeof mode[type] == "string") {
        if (help[mode[type]]) { found.push(help[mode[type]]) }
      } else if (mode[type]) {
        for (var i = 0; i < mode[type].length; i++) {
          var val = help[mode[type][i]]
          if (val) { found.push(val) }
        }
      } else if (mode.helperType && help[mode.helperType]) {
        found.push(help[mode.helperType])
      } else if (help[mode.name]) {
        found.push(help[mode.name])
      }
      for (var i$1 = 0; i$1 < help._global.length; i$1++) {
        var cur = help._global[i$1]
        if (cur.pred(mode, this$1) && indexOf(found, cur.val) == -1)
          { found.push(cur.val) }
      }
      return found
    },

    getStateAfter: function(line, precise) {
      var doc = this.doc
      line = clipLine(doc, line == null ? doc.first + doc.size - 1: line)
      return getContextBefore(this, line + 1, precise).state
    },

    cursorCoords: function(start, mode) {
      var pos, range = this.doc.sel.primary()
      if (start == null) { pos = range.head }
      else if (typeof start == "object") { pos = clipPos(this.doc, start) }
      else { pos = start ? range.from() : range.to() }
      return cursorCoords(this, pos, mode || "page")
    },

    charCoords: function(pos, mode) {
      return charCoords(this, clipPos(this.doc, pos), mode || "page")
    },

    coordsChar: function(coords, mode) {
      coords = fromCoordSystem(this, coords, mode || "page")
      return coordsChar(this, coords.left, coords.top)
    },

    lineAtHeight: function(height, mode) {
      height = fromCoordSystem(this, {top: height, left: 0}, mode || "page").top
      return lineAtHeight(this.doc, height + this.display.viewOffset)
    },
    heightAtLine: function(line, mode, includeWidgets) {
      var end = false, lineObj
      if (typeof line == "number") {
        var last = this.doc.first + this.doc.size - 1
        if (line < this.doc.first) { line = this.doc.first }
        else if (line > last) { line = last; end = true }
        lineObj = getLine(this.doc, line)
      } else {
        lineObj = line
      }
      return intoCoordSystem(this, lineObj, {top: 0, left: 0}, mode || "page", includeWidgets || end).top +
        (end ? this.doc.height - heightAtLine(lineObj) : 0)
    },

    defaultTextHeight: function() { return textHeight(this.display) },
    defaultCharWidth: function() { return charWidth(this.display) },

    getViewport: function() { return {from: this.display.viewFrom, to: this.display.viewTo}},

    addWidget: function(pos, node, scroll, vert, horiz) {
      var display = this.display
      pos = cursorCoords(this, clipPos(this.doc, pos))
      var top = pos.bottom, left = pos.left
      node.style.position = "absolute"
      node.setAttribute("cm-ignore-events", "true")
      this.display.input.setUneditable(node)
      display.sizer.appendChild(node)
      if (vert == "over") {
        top = pos.top
      } else if (vert == "above" || vert == "near") {
        var vspace = Math.max(display.wrapper.clientHeight, this.doc.height),
        hspace = Math.max(display.sizer.clientWidth, display.lineSpace.clientWidth)
        // Default to positioning above (if specified and possible); otherwise default to positioning below
        if ((vert == 'above' || pos.bottom + node.offsetHeight > vspace) && pos.top > node.offsetHeight)
          { top = pos.top - node.offsetHeight }
        else if (pos.bottom + node.offsetHeight <= vspace)
          { top = pos.bottom }
        if (left + node.offsetWidth > hspace)
          { left = hspace - node.offsetWidth }
      }
      node.style.top = top + "px"
      node.style.left = node.style.right = ""
      if (horiz == "right") {
        left = display.sizer.clientWidth - node.offsetWidth
        node.style.right = "0px"
      } else {
        if (horiz == "left") { left = 0 }
        else if (horiz == "middle") { left = (display.sizer.clientWidth - node.offsetWidth) / 2 }
        node.style.left = left + "px"
      }
      if (scroll)
        { scrollIntoView(this, {left: left, top: top, right: left + node.offsetWidth, bottom: top + node.offsetHeight}) }
    },

    triggerOnKeyDown: methodOp(onKeyDown),
    triggerOnKeyPress: methodOp(onKeyPress),
    triggerOnKeyUp: onKeyUp,
    triggerOnMouseDown: methodOp(onMouseDown),

    execCommand: function(cmd) {
      if (commands.hasOwnProperty(cmd))
        { return commands[cmd].call(null, this) }
    },

    triggerElectric: methodOp(function(text) { triggerElectric(this, text) }),

    findPosH: function(from, amount, unit, visually) {
      var this$1 = this;

      var dir = 1
      if (amount < 0) { dir = -1; amount = -amount }
      var cur = clipPos(this.doc, from)
      for (var i = 0; i < amount; ++i) {
        cur = findPosH(this$1.doc, cur, dir, unit, visually)
        if (cur.hitSide) { break }
      }
      return cur
    },

    moveH: methodOp(function(dir, unit) {
      var this$1 = this;

      this.extendSelectionsBy(function (range) {
        if (this$1.display.shift || this$1.doc.extend || range.empty())
          { return findPosH(this$1.doc, range.head, dir, unit, this$1.options.rtlMoveVisually) }
        else
          { return dir < 0 ? range.from() : range.to() }
      }, sel_move)
    }),

    deleteH: methodOp(function(dir, unit) {
      var sel = this.doc.sel, doc = this.doc
      if (sel.somethingSelected())
        { doc.replaceSelection("", null, "+delete") }
      else
        { deleteNearSelection(this, function (range) {
          var other = findPosH(doc, range.head, dir, unit, false)
          return dir < 0 ? {from: other, to: range.head} : {from: range.head, to: other}
        }) }
    }),

    findPosV: function(from, amount, unit, goalColumn) {
      var this$1 = this;

      var dir = 1, x = goalColumn
      if (amount < 0) { dir = -1; amount = -amount }
      var cur = clipPos(this.doc, from)
      for (var i = 0; i < amount; ++i) {
        var coords = cursorCoords(this$1, cur, "div")
        if (x == null) { x = coords.left }
        else { coords.left = x }
        cur = findPosV(this$1, coords, dir, unit)
        if (cur.hitSide) { break }
      }
      return cur
    },

    moveV: methodOp(function(dir, unit) {
      var this$1 = this;

      var doc = this.doc, goals = []
      var collapse = !this.display.shift && !doc.extend && doc.sel.somethingSelected()
      doc.extendSelectionsBy(function (range) {
        if (collapse)
          { return dir < 0 ? range.from() : range.to() }
        var headPos = cursorCoords(this$1, range.head, "div")
        if (range.goalColumn != null) { headPos.left = range.goalColumn }
        goals.push(headPos.left)
        var pos = findPosV(this$1, headPos, dir, unit)
        if (unit == "page" && range == doc.sel.primary())
          { addToScrollTop(this$1, charCoords(this$1, pos, "div").top - headPos.top) }
        return pos
      }, sel_move)
      if (goals.length) { for (var i = 0; i < doc.sel.ranges.length; i++)
        { doc.sel.ranges[i].goalColumn = goals[i] } }
    }),

    // Find the word at the given position (as returned by coordsChar).
    findWordAt: function(pos) {
      var doc = this.doc, line = getLine(doc, pos.line).text
      var start = pos.ch, end = pos.ch
      if (line) {
        var helper = this.getHelper(pos, "wordChars")
        if ((pos.sticky == "before" || end == line.length) && start) { --start; } else { ++end }
        var startChar = line.charAt(start)
        var check = isWordChar(startChar, helper)
          ? function (ch) { return isWordChar(ch, helper); }
          : /\s/.test(startChar) ? function (ch) { return /\s/.test(ch); }
          : function (ch) { return (!/\s/.test(ch) && !isWordChar(ch)); }
        while (start > 0 && check(line.charAt(start - 1))) { --start }
        while (end < line.length && check(line.charAt(end))) { ++end }
      }
      return new Range(Pos(pos.line, start), Pos(pos.line, end))
    },

    toggleOverwrite: function(value) {
      if (value != null && value == this.state.overwrite) { return }
      if (this.state.overwrite = !this.state.overwrite)
        { addClass(this.display.cursorDiv, "CodeMirror-overwrite") }
      else
        { rmClass(this.display.cursorDiv, "CodeMirror-overwrite") }

      signal(this, "overwriteToggle", this, this.state.overwrite)
    },
    hasFocus: function() { return this.display.input.getField() == activeElt() },
    isReadOnly: function() { return !!(this.options.readOnly || this.doc.cantEdit) },

    scrollTo: methodOp(function (x, y) { scrollToCoords(this, x, y) }),
    getScrollInfo: function() {
      var scroller = this.display.scroller
      return {left: scroller.scrollLeft, top: scroller.scrollTop,
              height: scroller.scrollHeight - scrollGap(this) - this.display.barHeight,
              width: scroller.scrollWidth - scrollGap(this) - this.display.barWidth,
              clientHeight: displayHeight(this), clientWidth: displayWidth(this)}
    },

    scrollIntoView: methodOp(function(range, margin) {
      if (range == null) {
        range = {from: this.doc.sel.primary().head, to: null}
        if (margin == null) { margin = this.options.cursorScrollMargin }
      } else if (typeof range == "number") {
        range = {from: Pos(range, 0), to: null}
      } else if (range.from == null) {
        range = {from: range, to: null}
      }
      if (!range.to) { range.to = range.from }
      range.margin = margin || 0

      if (range.from.line != null) {
        scrollToRange(this, range)
      } else {
        scrollToCoordsRange(this, range.from, range.to, range.margin)
      }
    }),

    setSize: methodOp(function(width, height) {
      var this$1 = this;

      var interpret = function (val) { return typeof val == "number" || /^\d+$/.test(String(val)) ? val + "px" : val; }
      if (width != null) { this.display.wrapper.style.width = interpret(width) }
      if (height != null) { this.display.wrapper.style.height = interpret(height) }
      if (this.options.lineWrapping) { clearLineMeasurementCache(this) }
      var lineNo = this.display.viewFrom
      this.doc.iter(lineNo, this.display.viewTo, function (line) {
        if (line.widgets) { for (var i = 0; i < line.widgets.length; i++)
          { if (line.widgets[i].noHScroll) { regLineChange(this$1, lineNo, "widget"); break } } }
        ++lineNo
      })
      this.curOp.forceUpdate = true
      signal(this, "refresh", this)
    }),

    operation: function(f){return runInOp(this, f)},
    startOperation: function(){return startOperation(this)},
    endOperation: function(){return endOperation(this)},

    refresh: methodOp(function() {
      var oldHeight = this.display.cachedTextHeight
      regChange(this)
      this.curOp.forceUpdate = true
      clearCaches(this)
      scrollToCoords(this, this.doc.scrollLeft, this.doc.scrollTop)
      updateGutterSpace(this)
      if (oldHeight == null || Math.abs(oldHeight - textHeight(this.display)) > .5)
        { estimateLineHeights(this) }
      signal(this, "refresh", this)
    }),

    swapDoc: methodOp(function(doc) {
      var old = this.doc
      old.cm = null
      attachDoc(this, doc)
      clearCaches(this)
      this.display.input.reset()
      scrollToCoords(this, doc.scrollLeft, doc.scrollTop)
      this.curOp.forceScroll = true
      signalLater(this, "swapDoc", this, old)
      return old
    }),

    phrase: function(phraseText) {
      var phrases = this.options.phrases
      return phrases && Object.prototype.hasOwnProperty.call(phrases, phraseText) ? phrases[phraseText] : phraseText
    },

    getInputField: function(){return this.display.input.getField()},
    getWrapperElement: function(){return this.display.wrapper},
    getScrollerElement: function(){return this.display.scroller},
    getGutterElement: function(){return this.display.gutters}
  }
  eventMixin(CodeMirror)

  CodeMirror.registerHelper = function(type, name, value) {
    if (!helpers.hasOwnProperty(type)) { helpers[type] = CodeMirror[type] = {_global: []} }
    helpers[type][name] = value
  }
  CodeMirror.registerGlobalHelper = function(type, name, predicate, value) {
    CodeMirror.registerHelper(type, name, value)
    helpers[type]._global.push({pred: predicate, val: value})
  }
}

// Used for horizontal relative motion. Dir is -1 or 1 (left or
// right), unit can be "char", "column" (like char, but doesn't
// cross line boundaries), "word" (across next word), or "group" (to
// the start of next group of word or non-word-non-whitespace
// chars). The visually param controls whether, in right-to-left
// text, direction 1 means to move towards the next index in the
// string, or towards the character to the right of the current
// position. The resulting position will have a hitSide=true
// property if it reached the end of the document.
function findPosH(doc, pos, dir, unit, visually) {
  var oldPos = pos
  var origDir = dir
  var lineObj = getLine(doc, pos.line)
  function findNextLine() {
    var l = pos.line + dir
    if (l < doc.first || l >= doc.first + doc.size) { return false }
    pos = new Pos(l, pos.ch, pos.sticky)
    return lineObj = getLine(doc, l)
  }
  function moveOnce(boundToLine) {
    var next
    if (visually) {
      next = moveVisually(doc.cm, lineObj, pos, dir)
    } else {
      next = moveLogically(lineObj, pos, dir)
    }
    if (next == null) {
      if (!boundToLine && findNextLine())
        { pos = endOfLine(visually, doc.cm, lineObj, pos.line, dir) }
      else
        { return false }
    } else {
      pos = next
    }
    return true
  }

  if (unit == "char") {
    moveOnce()
  } else if (unit == "column") {
    moveOnce(true)
  } else if (unit == "word" || unit == "group") {
    var sawType = null, group = unit == "group"
    var helper = doc.cm && doc.cm.getHelper(pos, "wordChars")
    for (var first = true;; first = false) {
      if (dir < 0 && !moveOnce(!first)) { break }
      var cur = lineObj.text.charAt(pos.ch) || "\n"
      var type = isWordChar(cur, helper) ? "w"
        : group && cur == "\n" ? "n"
        : !group || /\s/.test(cur) ? null
        : "p"
      if (group && !first && !type) { type = "s" }
      if (sawType && sawType != type) {
        if (dir < 0) {dir = 1; moveOnce(); pos.sticky = "after"}
        break
      }

      if (type) { sawType = type }
      if (dir > 0 && !moveOnce(!first)) { break }
    }
  }
  var result = skipAtomic(doc, pos, oldPos, origDir, true)
  if (equalCursorPos(oldPos, result)) { result.hitSide = true }
  return result
}

// For relative vertical movement. Dir may be -1 or 1. Unit can be
// "page" or "line". The resulting position will have a hitSide=true
// property if it reached the end of the document.
function findPosV(cm, pos, dir, unit) {
  var doc = cm.doc, x = pos.left, y
  if (unit == "page") {
    var pageSize = Math.min(cm.display.wrapper.clientHeight, window.innerHeight || document.documentElement.clientHeight)
    var moveAmount = Math.max(pageSize - .5 * textHeight(cm.display), 3)
    y = (dir > 0 ? pos.bottom : pos.top) + dir * moveAmount

  } else if (unit == "line") {
    y = dir > 0 ? pos.bottom + 3 : pos.top - 3
  }
  var target
  for (;;) {
    target = coordsChar(cm, x, y)
    if (!target.outside) { break }
    if (dir < 0 ? y <= 0 : y >= doc.height) { target.hitSide = true; break }
    y += dir * 5
  }
  return target
}

// CONTENTEDITABLE INPUT STYLE

var ContentEditableInput = function(cm) {
  this.cm = cm
  this.lastAnchorNode = this.lastAnchorOffset = this.lastFocusNode = this.lastFocusOffset = null
  this.polling = new Delayed()
  this.composing = null
  this.gracePeriod = false
  this.readDOMTimeout = null
};

ContentEditableInput.prototype.init = function (display) {
    var this$1 = this;

  var input = this, cm = input.cm
  var div = input.div = display.lineDiv
  disableBrowserMagic(div, cm.options.spellcheck)

  on(div, "paste", function (e) {
    if (signalDOMEvent(cm, e) || handlePaste(e, cm)) { return }
    // IE doesn't fire input events, so we schedule a read for the pasted content in this way
    if (ie_version <= 11) { setTimeout(operation(cm, function () { return this$1.updateFromDOM(); }), 20) }
  })

  on(div, "compositionstart", function (e) {
    this$1.composing = {data: e.data, done: false}
  })
  on(div, "compositionupdate", function (e) {
    if (!this$1.composing) { this$1.composing = {data: e.data, done: false} }
  })
  on(div, "compositionend", function (e) {
    if (this$1.composing) {
      if (e.data != this$1.composing.data) { this$1.readFromDOMSoon() }
      this$1.composing.done = true
    }
  })

  on(div, "touchstart", function () { return input.forceCompositionEnd(); })

  on(div, "input", function () {
    if (!this$1.composing) { this$1.readFromDOMSoon() }
  })

  function onCopyCut(e) {
    if (signalDOMEvent(cm, e)) { return }
    if (cm.somethingSelected()) {
      setLastCopied({lineWise: false, text: cm.getSelections()})
      if (e.type == "cut") { cm.replaceSelection("", null, "cut") }
    } else if (!cm.options.lineWiseCopyCut) {
      return
    } else {
      var ranges = copyableRanges(cm)
      setLastCopied({lineWise: true, text: ranges.text})
      if (e.type == "cut") {
        cm.operation(function () {
          cm.setSelections(ranges.ranges, 0, sel_dontScroll)
          cm.replaceSelection("", null, "cut")
        })
      }
    }
    if (e.clipboardData) {
      e.clipboardData.clearData()
      var content = lastCopied.text.join("\n")
      // iOS exposes the clipboard API, but seems to discard content inserted into it
      e.clipboardData.setData("Text", content)
      if (e.clipboardData.getData("Text") == content) {
        e.preventDefault()
        return
      }
    }
    // Old-fashioned briefly-focus-a-textarea hack
    var kludge = hiddenTextarea(), te = kludge.firstChild
    cm.display.lineSpace.insertBefore(kludge, cm.display.lineSpace.firstChild)
    te.value = lastCopied.text.join("\n")
    var hadFocus = document.activeElement
    selectInput(te)
    setTimeout(function () {
      cm.display.lineSpace.removeChild(kludge)
      hadFocus.focus()
      if (hadFocus == div) { input.showPrimarySelection() }
    }, 50)
  }
  on(div, "copy", onCopyCut)
  on(div, "cut", onCopyCut)
};

ContentEditableInput.prototype.prepareSelection = function () {
  var result = prepareSelection(this.cm, false)
  result.focus = this.cm.state.focused
  return result
};

ContentEditableInput.prototype.showSelection = function (info, takeFocus) {
  if (!info || !this.cm.display.view.length) { return }
  if (info.focus || takeFocus) { this.showPrimarySelection() }
  this.showMultipleSelections(info)
};

ContentEditableInput.prototype.getSelection = function () {
  return this.cm.display.wrapper.ownerDocument.getSelection()
};

ContentEditableInput.prototype.showPrimarySelection = function () {
  var sel = this.getSelection(), cm = this.cm, prim = cm.doc.sel.primary()
  var from = prim.from(), to = prim.to()

  if (cm.display.viewTo == cm.display.viewFrom || from.line >= cm.display.viewTo || to.line < cm.display.viewFrom) {
    sel.removeAllRanges()
    return
  }

  var curAnchor = domToPos(cm, sel.anchorNode, sel.anchorOffset)
  var curFocus = domToPos(cm, sel.focusNode, sel.focusOffset)
  if (curAnchor && !curAnchor.bad && curFocus && !curFocus.bad &&
      cmp(minPos(curAnchor, curFocus), from) == 0 &&
      cmp(maxPos(curAnchor, curFocus), to) == 0)
    { return }

  var view = cm.display.view
  var start = (from.line >= cm.display.viewFrom && posToDOM(cm, from)) ||
      {node: view[0].measure.map[2], offset: 0}
  var end = to.line < cm.display.viewTo && posToDOM(cm, to)
  if (!end) {
    var measure = view[view.length - 1].measure
    var map = measure.maps ? measure.maps[measure.maps.length - 1] : measure.map
    end = {node: map[map.length - 1], offset: map[map.length - 2] - map[map.length - 3]}
  }

  if (!start || !end) {
    sel.removeAllRanges()
    return
  }

  var old = sel.rangeCount && sel.getRangeAt(0), rng
  try { rng = range(start.node, start.offset, end.offset, end.node) }
  catch(e) {} // Our model of the DOM might be outdated, in which case the range we try to set can be impossible
  if (rng) {
    if (!gecko && cm.state.focused) {
      sel.collapse(start.node, start.offset)
      if (!rng.collapsed) {
        sel.removeAllRanges()
        sel.addRange(rng)
      }
    } else {
      sel.removeAllRanges()
      sel.addRange(rng)
    }
    if (old && sel.anchorNode == null) { sel.addRange(old) }
    else if (gecko) { this.startGracePeriod() }
  }
  this.rememberSelection()
};

ContentEditableInput.prototype.startGracePeriod = function () {
    var this$1 = this;

  clearTimeout(this.gracePeriod)
  this.gracePeriod = setTimeout(function () {
    this$1.gracePeriod = false
    if (this$1.selectionChanged())
      { this$1.cm.operation(function () { return this$1.cm.curOp.selectionChanged = true; }) }
  }, 20)
};

ContentEditableInput.prototype.showMultipleSelections = function (info) {
  removeChildrenAndAdd(this.cm.display.cursorDiv, info.cursors)
  removeChildrenAndAdd(this.cm.display.selectionDiv, info.selection)
};

ContentEditableInput.prototype.rememberSelection = function () {
  var sel = this.getSelection()
  this.lastAnchorNode = sel.anchorNode; this.lastAnchorOffset = sel.anchorOffset
  this.lastFocusNode = sel.focusNode; this.lastFocusOffset = sel.focusOffset
};

ContentEditableInput.prototype.selectionInEditor = function () {
  var sel = this.getSelection()
  if (!sel.rangeCount) { return false }
  var node = sel.getRangeAt(0).commonAncestorContainer
  return contains(this.div, node)
};

ContentEditableInput.prototype.focus = function () {
  if (this.cm.options.readOnly != "nocursor") {
    if (!this.selectionInEditor())
      { this.showSelection(this.prepareSelection(), true) }
    this.div.focus()
  }
};
ContentEditableInput.prototype.blur = function () { this.div.blur() };
ContentEditableInput.prototype.getField = function () { return this.div };

ContentEditableInput.prototype.supportsTouch = function () { return true };

ContentEditableInput.prototype.receivedFocus = function () {
  var input = this
  if (this.selectionInEditor())
    { this.pollSelection() }
  else
    { runInOp(this.cm, function () { return input.cm.curOp.selectionChanged = true; }) }

  function poll() {
    if (input.cm.state.focused) {
      input.pollSelection()
      input.polling.set(input.cm.options.pollInterval, poll)
    }
  }
  this.polling.set(this.cm.options.pollInterval, poll)
};

ContentEditableInput.prototype.selectionChanged = function () {
  var sel = this.getSelection()
  return sel.anchorNode != this.lastAnchorNode || sel.anchorOffset != this.lastAnchorOffset ||
    sel.focusNode != this.lastFocusNode || sel.focusOffset != this.lastFocusOffset
};

ContentEditableInput.prototype.pollSelection = function () {
  if (this.readDOMTimeout != null || this.gracePeriod || !this.selectionChanged()) { return }
  var sel = this.getSelection(), cm = this.cm
  // On Android Chrome (version 56, at least), backspacing into an
  // uneditable block element will put the cursor in that element,
  // and then, because it's not editable, hide the virtual keyboard.
  // Because Android doesn't allow us to actually detect backspace
  // presses in a sane way, this code checks for when that happens
  // and simulates a backspace press in this case.
  if (android && chrome && this.cm.options.gutters.length && isInGutter(sel.anchorNode)) {
    this.cm.triggerOnKeyDown({type: "keydown", keyCode: 8, preventDefault: Math.abs})
    this.blur()
    this.focus()
    return
  }
  if (this.composing) { return }
  this.rememberSelection()
  var anchor = domToPos(cm, sel.anchorNode, sel.anchorOffset)
  var head = domToPos(cm, sel.focusNode, sel.focusOffset)
  if (anchor && head) { runInOp(cm, function () {
    setSelection(cm.doc, simpleSelection(anchor, head), sel_dontScroll)
    if (anchor.bad || head.bad) { cm.curOp.selectionChanged = true }
  }) }
};

ContentEditableInput.prototype.pollContent = function () {
  if (this.readDOMTimeout != null) {
    clearTimeout(this.readDOMTimeout)
    this.readDOMTimeout = null
  }

  var cm = this.cm, display = cm.display, sel = cm.doc.sel.primary()
  var from = sel.from(), to = sel.to()
  if (from.ch == 0 && from.line > cm.firstLine())
    { from = Pos(from.line - 1, getLine(cm.doc, from.line - 1).length) }
  if (to.ch == getLine(cm.doc, to.line).text.length && to.line < cm.lastLine())
    { to = Pos(to.line + 1, 0) }
  if (from.line < display.viewFrom || to.line > display.viewTo - 1) { return false }

  var fromIndex, fromLine, fromNode
  if (from.line == display.viewFrom || (fromIndex = findViewIndex(cm, from.line)) == 0) {
    fromLine = lineNo(display.view[0].line)
    fromNode = display.view[0].node
  } else {
    fromLine = lineNo(display.view[fromIndex].line)
    fromNode = display.view[fromIndex - 1].node.nextSibling
  }
  var toIndex = findViewIndex(cm, to.line)
  var toLine, toNode
  if (toIndex == display.view.length - 1) {
    toLine = display.viewTo - 1
    toNode = display.lineDiv.lastChild
  } else {
    toLine = lineNo(display.view[toIndex + 1].line) - 1
    toNode = display.view[toIndex + 1].node.previousSibling
  }

  if (!fromNode) { return false }
  var newText = cm.doc.splitLines(domTextBetween(cm, fromNode, toNode, fromLine, toLine))
  var oldText = getBetween(cm.doc, Pos(fromLine, 0), Pos(toLine, getLine(cm.doc, toLine).text.length))
  while (newText.length > 1 && oldText.length > 1) {
    if (lst(newText) == lst(oldText)) { newText.pop(); oldText.pop(); toLine-- }
    else if (newText[0] == oldText[0]) { newText.shift(); oldText.shift(); fromLine++ }
    else { break }
  }

  var cutFront = 0, cutEnd = 0
  var newTop = newText[0], oldTop = oldText[0], maxCutFront = Math.min(newTop.length, oldTop.length)
  while (cutFront < maxCutFront && newTop.charCodeAt(cutFront) == oldTop.charCodeAt(cutFront))
    { ++cutFront }
  var newBot = lst(newText), oldBot = lst(oldText)
  var maxCutEnd = Math.min(newBot.length - (newText.length == 1 ? cutFront : 0),
                           oldBot.length - (oldText.length == 1 ? cutFront : 0))
  while (cutEnd < maxCutEnd &&
         newBot.charCodeAt(newBot.length - cutEnd - 1) == oldBot.charCodeAt(oldBot.length - cutEnd - 1))
    { ++cutEnd }
  // Try to move start of change to start of selection if ambiguous
  if (newText.length == 1 && oldText.length == 1 && fromLine == from.line) {
    while (cutFront && cutFront > from.ch &&
           newBot.charCodeAt(newBot.length - cutEnd - 1) == oldBot.charCodeAt(oldBot.length - cutEnd - 1)) {
      cutFront--
      cutEnd++
    }
  }

  newText[newText.length - 1] = newBot.slice(0, newBot.length - cutEnd).replace(/^\u200b+/, "")
  newText[0] = newText[0].slice(cutFront).replace(/\u200b+$/, "")

  var chFrom = Pos(fromLine, cutFront)
  var chTo = Pos(toLine, oldText.length ? lst(oldText).length - cutEnd : 0)
  if (newText.length > 1 || newText[0] || cmp(chFrom, chTo)) {
    replaceRange(cm.doc, newText, chFrom, chTo, "+input")
    return true
  }
};

ContentEditableInput.prototype.ensurePolled = function () {
  this.forceCompositionEnd()
};
ContentEditableInput.prototype.reset = function () {
  this.forceCompositionEnd()
};
ContentEditableInput.prototype.forceCompositionEnd = function () {
  if (!this.composing) { return }
  clearTimeout(this.readDOMTimeout)
  this.composing = null
  this.updateFromDOM()
  this.div.blur()
  this.div.focus()
};
ContentEditableInput.prototype.readFromDOMSoon = function () {
    var this$1 = this;

  if (this.readDOMTimeout != null) { return }
  this.readDOMTimeout = setTimeout(function () {
    this$1.readDOMTimeout = null
    if (this$1.composing) {
      if (this$1.composing.done) { this$1.composing = null }
      else { return }
    }
    this$1.updateFromDOM()
  }, 80)
};

ContentEditableInput.prototype.updateFromDOM = function () {
    var this$1 = this;

  if (this.cm.isReadOnly() || !this.pollContent())
    { runInOp(this.cm, function () { return regChange(this$1.cm); }) }
};

ContentEditableInput.prototype.setUneditable = function (node) {
  node.contentEditable = "false"
};

ContentEditableInput.prototype.onKeyPress = function (e) {
  if (e.charCode == 0 || this.composing) { return }
  e.preventDefault()
  if (!this.cm.isReadOnly())
    { operation(this.cm, applyTextInput)(this.cm, String.fromCharCode(e.charCode == null ? e.keyCode : e.charCode), 0) }
};

ContentEditableInput.prototype.readOnlyChanged = function (val) {
  this.div.contentEditable = String(val != "nocursor")
};

ContentEditableInput.prototype.onContextMenu = function () {};
ContentEditableInput.prototype.resetPosition = function () {};

ContentEditableInput.prototype.needsContentAttribute = true

function posToDOM(cm, pos) {
  var view = findViewForLine(cm, pos.line)
  if (!view || view.hidden) { return null }
  var line = getLine(cm.doc, pos.line)
  var info = mapFromLineView(view, line, pos.line)

  var order = getOrder(line, cm.doc.direction), side = "left"
  if (order) {
    var partPos = getBidiPartAt(order, pos.ch)
    side = partPos % 2 ? "right" : "left"
  }
  var result = nodeAndOffsetInLineMap(info.map, pos.ch, side)
  result.offset = result.collapse == "right" ? result.end : result.start
  return result
}

function isInGutter(node) {
  for (var scan = node; scan; scan = scan.parentNode)
    { if (/CodeMirror-gutter-wrapper/.test(scan.className)) { return true } }
  return false
}

function badPos(pos, bad) { if (bad) { pos.bad = true; } return pos }

function domTextBetween(cm, from, to, fromLine, toLine) {
  var text = "", closing = false, lineSep = cm.doc.lineSeparator(), extraLinebreak = false
  function recognizeMarker(id) { return function (marker) { return marker.id == id; } }
  function close() {
    if (closing) {
      text += lineSep
      if (extraLinebreak) { text += lineSep }
      closing = extraLinebreak = false
    }
  }
  function addText(str) {
    if (str) {
      close()
      text += str
    }
  }
  function walk(node) {
    if (node.nodeType == 1) {
      var cmText = node.getAttribute("cm-text")
      if (cmText) {
        addText(cmText)
        return
      }
      var markerID = node.getAttribute("cm-marker"), range
      if (markerID) {
        var found = cm.findMarks(Pos(fromLine, 0), Pos(toLine + 1, 0), recognizeMarker(+markerID))
        if (found.length && (range = found[0].find(0)))
          { addText(getBetween(cm.doc, range.from, range.to).join(lineSep)) }
        return
      }
      if (node.getAttribute("contenteditable") == "false") { return }
      var isBlock = /^(pre|div|p|li|table|br)$/i.test(node.nodeName)
      if (!/^br$/i.test(node.nodeName) && node.textContent.length == 0) { return }

      if (isBlock) { close() }
      for (var i = 0; i < node.childNodes.length; i++)
        { walk(node.childNodes[i]) }

      if (/^(pre|p)$/i.test(node.nodeName)) { extraLinebreak = true }
      if (isBlock) { closing = true }
    } else if (node.nodeType == 3) {
      addText(node.nodeValue.replace(/\u200b/g, "").replace(/\u00a0/g, " "))
    }
  }
  for (;;) {
    walk(from)
    if (from == to) { break }
    from = from.nextSibling
    extraLinebreak = false
  }
  return text
}

function domToPos(cm, node, offset) {
  var lineNode
  if (node == cm.display.lineDiv) {
    lineNode = cm.display.lineDiv.childNodes[offset]
    if (!lineNode) { return badPos(cm.clipPos(Pos(cm.display.viewTo - 1)), true) }
    node = null; offset = 0
  } else {
    for (lineNode = node;; lineNode = lineNode.parentNode) {
      if (!lineNode || lineNode == cm.display.lineDiv) { return null }
      if (lineNode.parentNode && lineNode.parentNode == cm.display.lineDiv) { break }
    }
  }
  for (var i = 0; i < cm.display.view.length; i++) {
    var lineView = cm.display.view[i]
    if (lineView.node == lineNode)
      { return locateNodeInLineView(lineView, node, offset) }
  }
}

function locateNodeInLineView(lineView, node, offset) {
  var wrapper = lineView.text.firstChild, bad = false
  if (!node || !contains(wrapper, node)) { return badPos(Pos(lineNo(lineView.line), 0), true) }
  if (node == wrapper) {
    bad = true
    node = wrapper.childNodes[offset]
    offset = 0
    if (!node) {
      var line = lineView.rest ? lst(lineView.rest) : lineView.line
      return badPos(Pos(lineNo(line), line.text.length), bad)
    }
  }

  var textNode = node.nodeType == 3 ? node : null, topNode = node
  if (!textNode && node.childNodes.length == 1 && node.firstChild.nodeType == 3) {
    textNode = node.firstChild
    if (offset) { offset = textNode.nodeValue.length }
  }
  while (topNode.parentNode != wrapper) { topNode = topNode.parentNode }
  var measure = lineView.measure, maps = measure.maps

  function find(textNode, topNode, offset) {
    for (var i = -1; i < (maps ? maps.length : 0); i++) {
      var map = i < 0 ? measure.map : maps[i]
      for (var j = 0; j < map.length; j += 3) {
        var curNode = map[j + 2]
        if (curNode == textNode || curNode == topNode) {
          var line = lineNo(i < 0 ? lineView.line : lineView.rest[i])
          var ch = map[j] + offset
          if (offset < 0 || curNode != textNode) { ch = map[j + (offset ? 1 : 0)] }
          return Pos(line, ch)
        }
      }
    }
  }
  var found = find(textNode, topNode, offset)
  if (found) { return badPos(found, bad) }

  // FIXME this is all really shaky. might handle the few cases it needs to handle, but likely to cause problems
  for (var after = topNode.nextSibling, dist = textNode ? textNode.nodeValue.length - offset : 0; after; after = after.nextSibling) {
    found = find(after, after.firstChild, 0)
    if (found)
      { return badPos(Pos(found.line, found.ch - dist), bad) }
    else
      { dist += after.textContent.length }
  }
  for (var before = topNode.previousSibling, dist$1 = offset; before; before = before.previousSibling) {
    found = find(before, before.firstChild, -1)
    if (found)
      { return badPos(Pos(found.line, found.ch + dist$1), bad) }
    else
      { dist$1 += before.textContent.length }
  }
}

// TEXTAREA INPUT STYLE

var TextareaInput = function(cm) {
  this.cm = cm
  // See input.poll and input.reset
  this.prevInput = ""

  // Flag that indicates whether we expect input to appear real soon
  // now (after some event like 'keypress' or 'input') and are
  // polling intensively.
  this.pollingFast = false
  // Self-resetting timeout for the poller
  this.polling = new Delayed()
  // Used to work around IE issue with selection being forgotten when focus moves away from textarea
  this.hasSelection = false
  this.composing = null
};

TextareaInput.prototype.init = function (display) {
    var this$1 = this;

  var input = this, cm = this.cm
  this.createField(display)
  var te = this.textarea

  display.wrapper.insertBefore(this.wrapper, display.wrapper.firstChild)

  // Needed to hide big blue blinking cursor on Mobile Safari (doesn't seem to work in iOS 8 anymore)
  if (ios) { te.style.width = "0px" }

  on(te, "input", function () {
    if (ie && ie_version >= 9 && this$1.hasSelection) { this$1.hasSelection = null }
    input.poll()
  })

  on(te, "paste", function (e) {
    if (signalDOMEvent(cm, e) || handlePaste(e, cm)) { return }

    cm.state.pasteIncoming = true
    input.fastPoll()
  })

  function prepareCopyCut(e) {
    if (signalDOMEvent(cm, e)) { return }
    if (cm.somethingSelected()) {
      setLastCopied({lineWise: false, text: cm.getSelections()})
    } else if (!cm.options.lineWiseCopyCut) {
      return
    } else {
      var ranges = copyableRanges(cm)
      setLastCopied({lineWise: true, text: ranges.text})
      if (e.type == "cut") {
        cm.setSelections(ranges.ranges, null, sel_dontScroll)
      } else {
        input.prevInput = ""
        te.value = ranges.text.join("\n")
        selectInput(te)
      }
    }
    if (e.type == "cut") { cm.state.cutIncoming = true }
  }
  on(te, "cut", prepareCopyCut)
  on(te, "copy", prepareCopyCut)

  on(display.scroller, "paste", function (e) {
    if (eventInWidget(display, e) || signalDOMEvent(cm, e)) { return }
    cm.state.pasteIncoming = true
    input.focus()
  })

  // Prevent normal selection in the editor (we handle our own)
  on(display.lineSpace, "selectstart", function (e) {
    if (!eventInWidget(display, e)) { e_preventDefault(e) }
  })

  on(te, "compositionstart", function () {
    var start = cm.getCursor("from")
    if (input.composing) { input.composing.range.clear() }
    input.composing = {
      start: start,
      range: cm.markText(start, cm.getCursor("to"), {className: "CodeMirror-composing"})
    }
  })
  on(te, "compositionend", function () {
    if (input.composing) {
      input.poll()
      input.composing.range.clear()
      input.composing = null
    }
  })
};

TextareaInput.prototype.createField = function (_display) {
  // Wraps and hides input textarea
  this.wrapper = hiddenTextarea()
  // The semihidden textarea that is focused when the editor is
  // focused, and receives input.
  this.textarea = this.wrapper.firstChild
};

TextareaInput.prototype.prepareSelection = function () {
  // Redraw the selection and/or cursor
  var cm = this.cm, display = cm.display, doc = cm.doc
  var result = prepareSelection(cm)

  // Move the hidden textarea near the cursor to prevent scrolling artifacts
  if (cm.options.moveInputWithCursor) {
    var headPos = cursorCoords(cm, doc.sel.primary().head, "div")
    var wrapOff = display.wrapper.getBoundingClientRect(), lineOff = display.lineDiv.getBoundingClientRect()
    result.teTop = Math.max(0, Math.min(display.wrapper.clientHeight - 10,
                                        headPos.top + lineOff.top - wrapOff.top))
    result.teLeft = Math.max(0, Math.min(display.wrapper.clientWidth - 10,
                                         headPos.left + lineOff.left - wrapOff.left))
  }

  return result
};

TextareaInput.prototype.showSelection = function (drawn) {
  var cm = this.cm, display = cm.display
  removeChildrenAndAdd(display.cursorDiv, drawn.cursors)
  removeChildrenAndAdd(display.selectionDiv, drawn.selection)
  if (drawn.teTop != null) {
    this.wrapper.style.top = drawn.teTop + "px"
    this.wrapper.style.left = drawn.teLeft + "px"
  }
};

// Reset the input to correspond to the selection (or to be empty,
// when not typing and nothing is selected)
TextareaInput.prototype.reset = function (typing) {
  if (this.contextMenuPending || this.composing) { return }
  var cm = this.cm
  if (cm.somethingSelected()) {
    this.prevInput = ""
    var content = cm.getSelection()
    this.textarea.value = content
    if (cm.state.focused) { selectInput(this.textarea) }
    if (ie && ie_version >= 9) { this.hasSelection = content }
  } else if (!typing) {
    this.prevInput = this.textarea.value = ""
    if (ie && ie_version >= 9) { this.hasSelection = null }
  }
};

TextareaInput.prototype.getField = function () { return this.textarea };

TextareaInput.prototype.supportsTouch = function () { return false };

TextareaInput.prototype.focus = function () {
  if (this.cm.options.readOnly != "nocursor" && (!mobile || activeElt() != this.textarea)) {
    try { this.textarea.focus() }
    catch (e) {} // IE8 will throw if the textarea is display: none or not in DOM
  }
};

TextareaInput.prototype.blur = function () { this.textarea.blur() };

TextareaInput.prototype.resetPosition = function () {
  this.wrapper.style.top = this.wrapper.style.left = 0
};

TextareaInput.prototype.receivedFocus = function () { this.slowPoll() };

// Poll for input changes, using the normal rate of polling. This
// runs as long as the editor is focused.
TextareaInput.prototype.slowPoll = function () {
    var this$1 = this;

  if (this.pollingFast) { return }
  this.polling.set(this.cm.options.pollInterval, function () {
    this$1.poll()
    if (this$1.cm.state.focused) { this$1.slowPoll() }
  })
};

// When an event has just come in that is likely to add or change
// something in the input textarea, we poll faster, to ensure that
// the change appears on the screen quickly.
TextareaInput.prototype.fastPoll = function () {
  var missed = false, input = this
  input.pollingFast = true
  function p() {
    var changed = input.poll()
    if (!changed && !missed) {missed = true; input.polling.set(60, p)}
    else {input.pollingFast = false; input.slowPoll()}
  }
  input.polling.set(20, p)
};

// Read input from the textarea, and update the document to match.
// When something is selected, it is present in the textarea, and
// selected (unless it is huge, in which case a placeholder is
// used). When nothing is selected, the cursor sits after previously
// seen text (can be empty), which is stored in prevInput (we must
// not reset the textarea when typing, because that breaks IME).
TextareaInput.prototype.poll = function () {
    var this$1 = this;

  var cm = this.cm, input = this.textarea, prevInput = this.prevInput
  // Since this is called a *lot*, try to bail out as cheaply as
  // possible when it is clear that nothing happened. hasSelection
  // will be the case when there is a lot of text in the textarea,
  // in which case reading its value would be expensive.
  if (this.contextMenuPending || !cm.state.focused ||
      (hasSelection(input) && !prevInput && !this.composing) ||
      cm.isReadOnly() || cm.options.disableInput || cm.state.keySeq)
    { return false }

  var text = input.value
  // If nothing changed, bail.
  if (text == prevInput && !cm.somethingSelected()) { return false }
  // Work around nonsensical selection resetting in IE9/10, and
  // inexplicable appearance of private area unicode characters on
  // some key combos in Mac (#2689).
  if (ie && ie_version >= 9 && this.hasSelection === text ||
      mac && /[\uf700-\uf7ff]/.test(text)) {
    cm.display.input.reset()
    return false
  }

  if (cm.doc.sel == cm.display.selForContextMenu) {
    var first = text.charCodeAt(0)
    if (first == 0x200b && !prevInput) { prevInput = "\u200b" }
    if (first == 0x21da) { this.reset(); return this.cm.execCommand("undo") }
  }
  // Find the part of the input that is actually new
  var same = 0, l = Math.min(prevInput.length, text.length)
  while (same < l && prevInput.charCodeAt(same) == text.charCodeAt(same)) { ++same }

  runInOp(cm, function () {
    applyTextInput(cm, text.slice(same), prevInput.length - same,
                   null, this$1.composing ? "*compose" : null)

    // Don't leave long text in the textarea, since it makes further polling slow
    if (text.length > 1000 || text.indexOf("\n") > -1) { input.value = this$1.prevInput = "" }
    else { this$1.prevInput = text }

    if (this$1.composing) {
      this$1.composing.range.clear()
      this$1.composing.range = cm.markText(this$1.composing.start, cm.getCursor("to"),
                                         {className: "CodeMirror-composing"})
    }
  })
  return true
};

TextareaInput.prototype.ensurePolled = function () {
  if (this.pollingFast && this.poll()) { this.pollingFast = false }
};

TextareaInput.prototype.onKeyPress = function () {
  if (ie && ie_version >= 9) { this.hasSelection = null }
  this.fastPoll()
};

TextareaInput.prototype.onContextMenu = function (e) {
  var input = this, cm = input.cm, display = cm.display, te = input.textarea
  var pos = posFromMouse(cm, e), scrollPos = display.scroller.scrollTop
  if (!pos || presto) { return } // Opera is difficult.

  // Reset the current text selection only if the click is done outside of the selection
  // and 'resetSelectionOnContextMenu' option is true.
  var reset = cm.options.resetSelectionOnContextMenu
  if (reset && cm.doc.sel.contains(pos) == -1)
    { operation(cm, setSelection)(cm.doc, simpleSelection(pos), sel_dontScroll) }

  var oldCSS = te.style.cssText, oldWrapperCSS = input.wrapper.style.cssText
  input.wrapper.style.cssText = "position: absolute"
  var wrapperBox = input.wrapper.getBoundingClientRect()
  te.style.cssText = "position: absolute; width: 30px; height: 30px;\n      top: " + (e.clientY - wrapperBox.top - 5) + "px; left: " + (e.clientX - wrapperBox.left - 5) + "px;\n      z-index: 1000; background: " + (ie ? "rgba(255, 255, 255, .05)" : "transparent") + ";\n      outline: none; border-width: 0; outline: none; overflow: hidden; opacity: .05; filter: alpha(opacity=5);"
  var oldScrollY
  if (webkit) { oldScrollY = window.scrollY } // Work around Chrome issue (#2712)
  display.input.focus()
  if (webkit) { window.scrollTo(null, oldScrollY) }
  display.input.reset()
  // Adds "Select all" to context menu in FF
  if (!cm.somethingSelected()) { te.value = input.prevInput = " " }
  input.contextMenuPending = true
  display.selForContextMenu = cm.doc.sel
  clearTimeout(display.detectingSelectAll)

  // Select-all will be greyed out if there's nothing to select, so
  // this adds a zero-width space so that we can later check whether
  // it got selected.
  function prepareSelectAllHack() {
    if (te.selectionStart != null) {
      var selected = cm.somethingSelected()
      var extval = "\u200b" + (selected ? te.value : "")
      te.value = "\u21da" // Used to catch context-menu undo
      te.value = extval
      input.prevInput = selected ? "" : "\u200b"
      te.selectionStart = 1; te.selectionEnd = extval.length
      // Re-set this, in case some other handler touched the
      // selection in the meantime.
      display.selForContextMenu = cm.doc.sel
    }
  }
  function rehide() {
    input.contextMenuPending = false
    input.wrapper.style.cssText = oldWrapperCSS
    te.style.cssText = oldCSS
    if (ie && ie_version < 9) { display.scrollbars.setScrollTop(display.scroller.scrollTop = scrollPos) }

    // Try to detect the user choosing select-all
    if (te.selectionStart != null) {
      if (!ie || (ie && ie_version < 9)) { prepareSelectAllHack() }
      var i = 0, poll = function () {
        if (display.selForContextMenu == cm.doc.sel && te.selectionStart == 0 &&
            te.selectionEnd > 0 && input.prevInput == "\u200b") {
          operation(cm, selectAll)(cm)
        } else if (i++ < 10) {
          display.detectingSelectAll = setTimeout(poll, 500)
        } else {
          display.selForContextMenu = null
          display.input.reset()
        }
      }
      display.detectingSelectAll = setTimeout(poll, 200)
    }
  }

  if (ie && ie_version >= 9) { prepareSelectAllHack() }
  if (captureRightClick) {
    e_stop(e)
    var mouseup = function () {
      off(window, "mouseup", mouseup)
      setTimeout(rehide, 20)
    }
    on(window, "mouseup", mouseup)
  } else {
    setTimeout(rehide, 50)
  }
};

TextareaInput.prototype.readOnlyChanged = function (val) {
  if (!val) { this.reset() }
  this.textarea.disabled = val == "nocursor"
};

TextareaInput.prototype.setUneditable = function () {};

TextareaInput.prototype.needsContentAttribute = false

function fromTextArea(textarea, options) {
  options = options ? copyObj(options) : {}
  options.value = textarea.value
  if (!options.tabindex && textarea.tabIndex)
    { options.tabindex = textarea.tabIndex }
  if (!options.placeholder && textarea.placeholder)
    { options.placeholder = textarea.placeholder }
  // Set autofocus to true if this textarea is focused, or if it has
  // autofocus and no other element is focused.
  if (options.autofocus == null) {
    var hasFocus = activeElt()
    options.autofocus = hasFocus == textarea ||
      textarea.getAttribute("autofocus") != null && hasFocus == document.body
  }

  function save() {textarea.value = cm.getValue()}

  var realSubmit
  if (textarea.form) {
    on(textarea.form, "submit", save)
    // Deplorable hack to make the submit method do the right thing.
    if (!options.leaveSubmitMethodAlone) {
      var form = textarea.form
      realSubmit = form.submit
      try {
        var wrappedSubmit = form.submit = function () {
          save()
          form.submit = realSubmit
          form.submit()
          form.submit = wrappedSubmit
        }
      } catch(e) {}
    }
  }

  options.finishInit = function (cm) {
    cm.save = save
    cm.getTextArea = function () { return textarea; }
    cm.toTextArea = function () {
      cm.toTextArea = isNaN // Prevent this from being ran twice
      save()
      textarea.parentNode.removeChild(cm.getWrapperElement())
      textarea.style.display = ""
      if (textarea.form) {
        off(textarea.form, "submit", save)
        if (typeof textarea.form.submit == "function")
          { textarea.form.submit = realSubmit }
      }
    }
  }

  textarea.style.display = "none"
  var cm = CodeMirror(function (node) { return textarea.parentNode.insertBefore(node, textarea.nextSibling); },
    options)
  return cm
}

function addLegacyProps(CodeMirror) {
  CodeMirror.off = off
  CodeMirror.on = on
  CodeMirror.wheelEventPixels = wheelEventPixels
  CodeMirror.Doc = Doc
  CodeMirror.splitLines = splitLinesAuto
  CodeMirror.countColumn = countColumn
  CodeMirror.findColumn = findColumn
  CodeMirror.isWordChar = isWordCharBasic
  CodeMirror.Pass = Pass
  CodeMirror.signal = signal
  CodeMirror.Line = Line
  CodeMirror.changeEnd = changeEnd
  CodeMirror.scrollbarModel = scrollbarModel
  CodeMirror.Pos = Pos
  CodeMirror.cmpPos = cmp
  CodeMirror.modes = modes
  CodeMirror.mimeModes = mimeModes
  CodeMirror.resolveMode = resolveMode
  CodeMirror.getMode = getMode
  CodeMirror.modeExtensions = modeExtensions
  CodeMirror.extendMode = extendMode
  CodeMirror.copyState = copyState
  CodeMirror.startState = startState
  CodeMirror.innerMode = innerMode
  CodeMirror.commands = commands
  CodeMirror.keyMap = keyMap
  CodeMirror.keyName = keyName
  CodeMirror.isModifierKey = isModifierKey
  CodeMirror.lookupKey = lookupKey
  CodeMirror.normalizeKeyMap = normalizeKeyMap
  CodeMirror.StringStream = StringStream
  CodeMirror.SharedTextMarker = SharedTextMarker
  CodeMirror.TextMarker = TextMarker
  CodeMirror.LineWidget = LineWidget
  CodeMirror.e_preventDefault = e_preventDefault
  CodeMirror.e_stopPropagation = e_stopPropagation
  CodeMirror.e_stop = e_stop
  CodeMirror.addClass = addClass
  CodeMirror.contains = contains
  CodeMirror.rmClass = rmClass
  CodeMirror.keyNames = keyNames
}

// EDITOR CONSTRUCTOR

defineOptions(CodeMirror)

addEditorMethods(CodeMirror)

// Set up methods on CodeMirror's prototype to redirect to the editor's document.
var dontDelegate = "iter insert remove copy getEditor constructor".split(" ")
for (var prop in Doc.prototype) { if (Doc.prototype.hasOwnProperty(prop) && indexOf(dontDelegate, prop) < 0)
  { CodeMirror.prototype[prop] = (function(method) {
    return function() {return method.apply(this.doc, arguments)}
  })(Doc.prototype[prop]) } }

eventMixin(Doc)

// INPUT HANDLING

CodeMirror.inputStyles = {"textarea": TextareaInput, "contenteditable": ContentEditableInput}

// MODE DEFINITION AND QUERYING

// Extra arguments are stored as the mode's dependencies, which is
// used by (legacy) mechanisms like loadmode.js to automatically
// load a mode. (Preferred mechanism is the require/define calls.)
CodeMirror.defineMode = function(name/*, mode, …*/) {
  if (!CodeMirror.defaults.mode && name != "null") { CodeMirror.defaults.mode = name }
  defineMode.apply(this, arguments)
}

CodeMirror.defineMIME = defineMIME

// Minimal default mode.
CodeMirror.defineMode("null", function () { return ({token: function (stream) { return stream.skipToEnd(); }}); })
CodeMirror.defineMIME("text/plain", "null")

// EXTENSIONS

CodeMirror.defineExtension = function (name, func) {
  CodeMirror.prototype[name] = func
}
CodeMirror.defineDocExtension = function (name, func) {
  Doc.prototype[name] = func
}

CodeMirror.fromTextArea = fromTextArea

addLegacyProps(CodeMirror)

CodeMirror.version = "5.40.2"

return CodeMirror;

})));