bsdsjj_siping/web/js/codemirror/lib/codemirror.js

// CodeMirror version 3.0
//
// CodeMirror is the only global var we claim
window.CodeMirror = (function() {
  "use strict";

  // BROWSER SNIFFING

  // Crude, but necessary to handle a number of hard-to-feature-detect
  // bugs and behavior differences.
  var gecko = /gecko\/\d/i.test(navigator.userAgent);
  var ie = /MSIE \d/.test(navigator.userAgent);
  var ie_lt8 = /MSIE [1-7]\b/.test(navigator.userAgent);
  var ie_lt9 = /MSIE [1-8]\b/.test(navigator.userAgent);
  var webkit = /WebKit\//.test(navigator.userAgent);
  var qtwebkit = webkit && /Qt\/\d+\.\d+/.test(navigator.userAgent);
  var chrome = /Chrome\//.test(navigator.userAgent);
  var opera = /Opera\//.test(navigator.userAgent);
  var safari = /Apple Computer/.test(navigator.vendor);
  var khtml = /KHTML\//.test(navigator.userAgent);
  var mac_geLion = /Mac OS X 1\d\D([7-9]|\d\d)\D/.test(navigator.userAgent);
  var mac_geMountainLion = /Mac OS X 1\d\D([8-9]|\d\d)\D/.test(navigator.userAgent);
  var phantom = /PhantomJS/.test(navigator.userAgent);

  var ios = /AppleWebKit/.test(navigator.userAgent) && /Mobile\/\w+/.test(navigator.userAgent);
  // This is woefully incomplete. Suggestions for alternative methods welcome.
  var mobile = ios || /Android|webOS|BlackBerry|Opera Mini|IEMobile/i.test(navigator.userAgent);
  var mac = ios || /Mac/.test(navigator.platform);

  // Optimize some code when these features are not used
  var sawReadOnlySpans = false, sawCollapsedSpans = false;

  // CONSTRUCTOR

  function CodeMirror(place, options) {
    if (!(this instanceof CodeMirror)) return new CodeMirror(place, options);
    
    this.options = options = options || {};
    // Determine effective options based on given values and defaults.
    for (var opt in defaults) if (!options.hasOwnProperty(opt) && defaults.hasOwnProperty(opt))
      options[opt] = defaults[opt];
    setGuttersForLineNumbers(options);

    var display = this.display = makeDisplay(place);
    display.wrapper.CodeMirror = this;
    updateGutters(this);
    if (options.autofocus && !mobile) focusInput(this);

    this.view = makeView(new BranchChunk([new LeafChunk([makeLine("", null, textHeight(display))])]));
    this.nextOpId = 0;
    loadMode(this);
    themeChanged(this);
    if (options.lineWrapping)
      this.display.wrapper.className += " CodeMirror-wrap";

    // Initialize the content.
    this.setValue(options.value || "");
    // Override magic textarea content restore that IE sometimes does
    // on our hidden textarea on reload
    if (ie) setTimeout(bind(resetInput, this, true), 20);
    this.view.history = makeHistory();

    registerEventHandlers(this);
    // IE throws unspecified error in certain cases, when
    // trying to access activeElement before onload
    var hasFocus; try { hasFocus = (document.activeElement == display.input); } catch(e) { }
    if (hasFocus || (options.autofocus && !mobile)) setTimeout(bind(onFocus, this), 20);
    else onBlur(this);

    operation(this, function() {
      for (var opt in optionHandlers)
        if (optionHandlers.propertyIsEnumerable(opt))
          optionHandlers[opt](this, options[opt], Init);
      for (var i = 0; i < initHooks.length; ++i) initHooks[i](this);
    })();
  }

  // DISPLAY CONSTRUCTOR

  function makeDisplay(place) {
    var d = {};
    var input = d.input = elt("textarea", null, null, "position: absolute; padding: 0; width: 1px; height: 1em; outline: none;");
    input.setAttribute("wrap", "off"); input.setAttribute("autocorrect", "off"); input.setAttribute("autocapitalize", "off");
    // Wraps and hides input textarea
    d.inputDiv = elt("div", [input], null, "overflow: hidden; position: relative; width: 3px; height: 0px;");
    // The actual fake scrollbars.
    d.scrollbarH = elt("div", [elt("div", null, null, "height: 1px")], "CodeMirror-hscrollbar");
    d.scrollbarV = elt("div", [elt("div", null, null, "width: 1px")], "CodeMirror-vscrollbar");
    d.scrollbarFiller = elt("div", null, "CodeMirror-scrollbar-filler");
    // DIVs containing the selection and the actual code
    d.lineDiv = elt("div");
    d.selectionDiv = elt("div", null, null, "position: relative; z-index: 1");
    // Blinky cursor, and element used to ensure cursor fits at the end of a line
    d.cursor = elt("pre", "\u00a0", "CodeMirror-cursor");
    // Secondary cursor, shown when on a 'jump' in bi-directional text
    d.otherCursor = elt("pre", "\u00a0", "CodeMirror-cursor CodeMirror-secondarycursor");
    // Used to measure text size
    d.measure = elt("div", null, "CodeMirror-measure");
    // Wraps everything that needs to exist inside the vertically-padded coordinate system
    d.lineSpace = elt("div", [d.measure, d.selectionDiv, d.lineDiv, d.cursor, d.otherCursor],
                         null, "position: relative; outline: none");
    // Moved around its parent to cover visible view
    d.mover = elt("div", [elt("div", [d.lineSpace], "CodeMirror-lines")], null, "position: relative");
    // Set to the height of the text, causes scrolling
    d.sizer = elt("div", [d.mover], "CodeMirror-sizer");
    // D is needed because behavior of elts with overflow: auto and padding is inconsistent across browsers
    d.heightForcer = elt("div", "\u00a0", null, "position: absolute; height: " + scrollerCutOff + "px");
    // Will contain the gutters, if any
    d.gutters = elt("div", null, "CodeMirror-gutters");
    d.lineGutter = null;
    // Helper element to properly size the gutter backgrounds
    var scrollerInner = elt("div", [d.sizer, d.heightForcer, d.gutters], null, "position: relative; min-height: 100%");
    // Provides scrolling
    d.scroller = elt("div", [scrollerInner], "CodeMirror-scroll");
    d.scroller.setAttribute("tabIndex", "-1");
    // The element in which the editor lives.
    d.wrapper = elt("div", [d.inputDiv, d.scrollbarH, d.scrollbarV,
                            d.scrollbarFiller, d.scroller], "CodeMirror");
    // Work around IE7 z-index bug
    if (ie_lt8) { d.gutters.style.zIndex = -1; d.scroller.style.paddingRight = 0; }
    if (place.appendChild) place.appendChild(d.wrapper); else place(d.wrapper);

    // Needed to hide big blue blinking cursor on Mobile Safari
    if (ios) input.style.width = "0px";
    if (!webkit) d.scroller.draggable = true;
    // Needed to handle Tab key in KHTML
    if (khtml) { d.inputDiv.style.height = "1px"; d.inputDiv.style.position = "absolute"; }
    // Need to set a minimum width to see the scrollbar on IE7 (but must not set it on IE8).
    else if (ie_lt8) d.scrollbarH.style.minWidth = d.scrollbarV.style.minWidth = "18px";

    // Current visible range (may be bigger than the view window).
    d.viewOffset = d.showingFrom = d.showingTo = d.lastSizeC = 0;

    // 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;
    // See readInput and resetInput
    d.prevInput = "";
    // Set to true when a non-horizontal-scrolling widget is added. As
    // an optimization, widget aligning is skipped when d is false.
    d.alignWidgets = false;
    // Flag that indicates whether we currently expect input to appear
    // (after some event like 'keypress' or 'input') and are polling
    // intensively.
    d.pollingFast = false;
    // Self-resetting timeout for the poller
    d.poll = new Delayed();
    // True when a drag from the editor is active
    d.draggingText = false;

    d.cachedCharWidth = d.cachedTextHeight = null;
    d.measureLineCache = [];
    d.measureLineCachePos = 0;

    // Tracks when resetInput has punted to just putting a short
    // string instead of the (large) selection.
    d.inaccurateSelection = false;

    // Used to adjust overwrite behaviour when a paste has been
    // detected
    d.pasteIncoming = false;

    return d;
  }

  // VIEW CONSTRUCTOR

  function makeView(doc) {
    var selPos = {line: 0, ch: 0};
    return {
      doc: doc,
      // frontier is the point up to which the content has been parsed,
      frontier: 0, highlight: new Delayed(),
      sel: {from: selPos, to: selPos, head: selPos, anchor: selPos, shift: false, extend: false},
      scrollTop: 0, scrollLeft: 0,
      overwrite: false, focused: false,
      // Tracks the maximum line length so that
      // the horizontal scrollbar can be kept
      // static when scrolling.
      maxLine: getLine(doc, 0),
      maxLineLength: 0,
      maxLineChanged: false,
      suppressEdits: false,
      goalColumn: null,
      cantEdit: false,
      keyMaps: []
    };
  }

  // STATE UPDATES

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

  function loadMode(cm) {
    var doc = cm.view.doc;
    cm.view.mode = CodeMirror.getMode(cm.options, cm.options.mode);
    doc.iter(0, doc.size, function(line) { line.stateAfter = null; });
    cm.view.frontier = 0;
    startWorker(cm, 100);
  }

  function wrappingChanged(cm) {
    var doc = cm.view.doc, th = textHeight(cm.display);
    if (cm.options.lineWrapping) {
      cm.display.wrapper.className += " CodeMirror-wrap";
      var perLine = cm.display.scroller.clientWidth / charWidth(cm.display) - 3;
      doc.iter(0, doc.size, function(line) {
        if (line.height == 0) return;
        var guess = Math.ceil(line.text.length / perLine) || 1;
        if (guess != 1) updateLineHeight(line, guess * th);
      });
      cm.display.sizer.style.minWidth = "";
    } else {
      cm.display.wrapper.className = cm.display.wrapper.className.replace(" CodeMirror-wrap", "");
      computeMaxLength(cm.view);
      doc.iter(0, doc.size, function(line) {
        if (line.height != 0) updateLineHeight(line, th);
      });
    }
    regChange(cm, 0, doc.size);
    clearCaches(cm);
    setTimeout(function(){updateScrollbars(cm.display, cm.view.doc.height);}, 100);
  }

  function keyMapChanged(cm) {
    var style = keyMap[cm.options.keyMap].style;
    cm.display.wrapper.className = cm.display.wrapper.className.replace(/\s*cm-keymap-\S+/g, "") +
      (style ? " cm-keymap-" + style : "");
  }

  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);
  }

  function guttersChanged(cm) {
    updateGutters(cm);
    updateDisplay(cm, true);
  }

  function updateGutters(cm) {
    var gutters = cm.display.gutters, specs = cm.options.gutters;
    removeChildren(gutters);
    for (var i = 0; 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";
  }

  function lineLength(doc, line) {
    if (line.height == 0) return 0;
    var len = line.text.length, merged, cur = line;
    while (merged = collapsedSpanAtStart(cur)) {
      var found = merged.find();
      cur = getLine(doc, found.from.line);
      len += found.from.ch - found.to.ch;
    }
    cur = line;
    while (merged = collapsedSpanAtEnd(cur)) {
      var found = merged.find();
      len -= cur.text.length - found.from.ch;
      cur = getLine(doc, found.to.line);
      len += cur.text.length - found.to.ch;
    }
    return len;
  }

  function computeMaxLength(view) {
    view.maxLine = getLine(view.doc, 0);
    view.maxLineLength = lineLength(view.doc, view.maxLine);
    view.maxLineChanged = true;
    view.doc.iter(1, view.doc.size, function(line) {
      var len = lineLength(view.doc, line);
      if (len > view.maxLineLength) {
        view.maxLineLength = len;
        view.maxLine = line;
      }
    });
  }

  // Make sure the gutters options contains the element
  // "CodeMirror-linenumbers" when the lineNumbers option is true.
  function setGuttersForLineNumbers(options) {
    var found = false;
    for (var i = 0; i < options.gutters.length; ++i) {
      if (options.gutters[i] == "CodeMirror-linenumbers") {
        if (options.lineNumbers) found = true;
        else options.gutters.splice(i--, 1);
      }
    }
    if (!found && options.lineNumbers)
      options.gutters.push("CodeMirror-linenumbers");
  }

  // SCROLLBARS

  // Re-synchronize the fake scrollbars with the actual size of the
  // content. Optionally force a scrollTop.
  function updateScrollbars(d /* display */, docHeight) {
    var totalHeight = docHeight + 2 * paddingTop(d);
    d.sizer.style.minHeight = d.heightForcer.style.top = totalHeight + "px";
    var scrollHeight = Math.max(totalHeight, d.scroller.scrollHeight);
    var needsH = d.scroller.scrollWidth > d.scroller.clientWidth;
    var needsV = scrollHeight > d.scroller.clientHeight;
    if (needsV) {
      d.scrollbarV.style.display = "block";
      d.scrollbarV.style.bottom = needsH ? scrollbarWidth(d.measure) + "px" : "0";
      d.scrollbarV.firstChild.style.height = 
        (scrollHeight - d.scroller.clientHeight + d.scrollbarV.clientHeight) + "px";
    } else d.scrollbarV.style.display = "";
    if (needsH) {
      d.scrollbarH.style.display = "block";
      d.scrollbarH.style.right = needsV ? scrollbarWidth(d.measure) + "px" : "0";
      d.scrollbarH.firstChild.style.width =
        (d.scroller.scrollWidth - d.scroller.clientWidth + d.scrollbarH.clientWidth) + "px";
    } else d.scrollbarH.style.display = "";
    if (needsH && needsV) {
      d.scrollbarFiller.style.display = "block";
      d.scrollbarFiller.style.height = d.scrollbarFiller.style.width = scrollbarWidth(d.measure) + "px";
    } else d.scrollbarFiller.style.display = "";

    if (mac_geLion && scrollbarWidth(d.measure) === 0)
      d.scrollbarV.style.minWidth = d.scrollbarH.style.minHeight = mac_geMountainLion ? "18px" : "12px";
  }

  function visibleLines(display, doc, viewPort) {
    var top = display.scroller.scrollTop, height = display.wrapper.clientHeight;
    if (typeof viewPort == "number") top = viewPort;
    else if (viewPort) {top = viewPort.top; height = viewPort.bottom - viewPort.top;}
    top = Math.floor(top - paddingTop(display));
    var bottom = Math.ceil(top + height);
    return {from: lineAtHeight(doc, top), to: lineAtHeight(doc, bottom)};
  }

  // LINE NUMBERS

  function alignHorizontally(cm) {
    var display = cm.display;
    if (!display.alignWidgets && !display.gutters.firstChild) return;
    var comp = compensateForHScroll(display) - display.scroller.scrollLeft + cm.view.scrollLeft;
    var gutterW = display.gutters.offsetWidth, l = comp + "px";
    for (var n = display.lineDiv.firstChild; n; n = n.nextSibling) if (n.alignable) {
      for (var i = 0, a = n.alignable; i < a.length; ++i) a[i].style.left = l;
    }
    display.gutters.style.left = (comp + gutterW) + "px";
  }

  function maybeUpdateLineNumberWidth(cm) {
    if (!cm.options.lineNumbers) return false;
    var doc = cm.view.doc, last = lineNumberFor(cm.options, 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);
      display.lineNumWidth = display.lineNumInnerWidth + padding;
      display.lineNumChars = display.lineNumInnerWidth ? last.length : -1;
      display.lineGutter.style.width = display.lineNumWidth + "px";
      return true;
    }
    return false;
  }

  function lineNumberFor(options, i) {
    return String(options.lineNumberFormatter(i + options.firstLineNumber));
  }
  function compensateForHScroll(display) {
    return display.scroller.getBoundingClientRect().left - display.sizer.getBoundingClientRect().left;
  }

  // DISPLAY DRAWING

  function updateDisplay(cm, changes, viewPort) {
    var oldFrom = cm.display.showingFrom, oldTo = cm.display.showingTo;
    var updated = updateDisplayInner(cm, changes, viewPort);
    if (updated) {
      signalLater(cm, cm, "update", cm);
      if (cm.display.showingFrom != oldFrom || cm.display.showingTo != oldTo)
        signalLater(cm, cm, "viewportChange", cm, cm.display.showingFrom, cm.display.showingTo);
    }
    updateSelection(cm);
    updateScrollbars(cm.display, cm.view.doc.height);

    return updated;
  }

  // Uses a set of changes plus the current scroll position to
  // determine which DOM updates have to be made, and makes the
  // updates.
  function updateDisplayInner(cm, changes, viewPort) {
    var display = cm.display, doc = cm.view.doc;
    if (!display.wrapper.clientWidth) {
      display.showingFrom = display.showingTo = display.viewOffset = 0;
      return;
    }

    // Compute the new visible window
    // If scrollTop is specified, use that to determine which lines
    // to render instead of the current scrollbar position.
    var visible = visibleLines(display, doc, viewPort);
    // Bail out if the visible area is already rendered and nothing changed.
    if (changes !== true && changes.length == 0 &&
        visible.from > display.showingFrom && visible.to < display.showingTo)
      return;

    if (changes && maybeUpdateLineNumberWidth(cm))
      changes = true;
    display.sizer.style.marginLeft = display.scrollbarH.style.left = display.gutters.offsetWidth + "px";

    // When merged lines are present, the line that needs to be
    // redrawn might not be the one that was changed.
    if (changes !== true && sawCollapsedSpans)
      for (var i = 0; i < changes.length; ++i) {
        var ch = changes[i], merged;
        while (merged = collapsedSpanAtStart(getLine(doc, ch.from))) {
          var from = merged.find().from.line;
          if (ch.diff) ch.diff -= ch.from - from;
          ch.from = from;
        }
      }

    // Used to determine which lines need their line numbers updated
    var positionsChangedFrom = changes === true ? 0 : Infinity;
    if (cm.options.lineNumbers && changes && changes !== true)
      for (var i = 0; i < changes.length; ++i)
        if (changes[i].diff) { positionsChangedFrom = changes[i].from; break; }

    var from = Math.max(visible.from - cm.options.viewportMargin, 0);
    var to = Math.min(doc.size, visible.to + cm.options.viewportMargin);
    if (display.showingFrom < from && from - display.showingFrom < 20) from = display.showingFrom;
    if (display.showingTo > to && display.showingTo - to < 20) to = Math.min(doc.size, display.showingTo);
    if (sawCollapsedSpans) {
      from = lineNo(visualLine(doc, getLine(doc, from)));
      while (to < doc.size && lineIsHidden(getLine(doc, to))) ++to;
    }

    // Create a range of theoretically intact lines, and punch holes
    // in that using the change info.
    var intact = changes === true ? [] :
      computeIntact([{from: display.showingFrom, to: display.showingTo}], changes);
    // Clip off the parts that won't be visible
    var intactLines = 0;
    for (var i = 0; i < intact.length; ++i) {
      var range = intact[i];
      if (range.from < from) range.from = from;
      if (range.to > to) range.to = to;
      if (range.from >= range.to) intact.splice(i--, 1);
      else intactLines += range.to - range.from;
    }
    if (intactLines == to - from && from == display.showingFrom && to == display.showingTo)
      return;
    intact.sort(function(a, b) {return a.from - b.from;});

    if (intactLines < (to - from) * .7) display.lineDiv.style.display = "none";
    patchDisplay(cm, from, to, intact, positionsChangedFrom);
    display.lineDiv.style.display = "";

    var different = from != display.showingFrom || to != display.showingTo ||
      display.lastSizeC != display.wrapper.clientHeight;
    // This is just a bogus formula that detects when the editor is
    // resized or the font size changes.
    if (different) display.lastSizeC = display.wrapper.clientHeight;
    display.showingFrom = from; display.showingTo = to;
    startWorker(cm, 100);

    var prevBottom = display.lineDiv.offsetTop;
    for (var node = display.lineDiv.firstChild, height; node; node = node.nextSibling) if (node.lineObj) {
      if (ie_lt8) {
        var bot = node.offsetTop + node.offsetHeight;
        height = bot - prevBottom;
        prevBottom = bot;
      } else {
        var box = node.getBoundingClientRect();
        height = box.bottom - box.top;
      }
      var diff = node.lineObj.height - height;
      if (height < 2) height = textHeight(display);
      if (diff > .001 || diff < -.001)
        updateLineHeight(node.lineObj, height);
    }
    display.viewOffset = heightAtLine(cm, getLine(doc, from));
    // Position the mover div to align with the current virtual scroll position
    display.mover.style.top = display.viewOffset + "px";
    return true;
  }

  function computeIntact(intact, changes) {
    for (var i = 0, l = changes.length || 0; i < l; ++i) {
      var change = changes[i], intact2 = [], diff = change.diff || 0;
      for (var j = 0, l2 = intact.length; j < l2; ++j) {
        var range = intact[j];
        if (change.to <= range.from && change.diff) {
          intact2.push({from: range.from + diff, to: range.to + diff});
        } else if (change.to <= range.from || change.from >= range.to) {
          intact2.push(range);
        } else {
          if (change.from > range.from)
            intact2.push({from: range.from, to: change.from});
          if (change.to < range.to)
            intact2.push({from: change.to + diff, to: range.to + diff});
        }
      }
      intact = intact2;
    }
    return intact;
  }

  function getDimensions(cm) {
    var d = cm.display, left = {}, width = {};
    for (var n = d.gutters.firstChild, i = 0; n; n = n.nextSibling, ++i) {
      left[cm.options.gutters[i]] = n.offsetLeft;
      width[cm.options.gutters[i]] = n.offsetWidth;
    }
    return {fixedPos: compensateForHScroll(d),
            gutterTotalWidth: d.gutters.offsetWidth,
            gutterLeft: left,
            gutterWidth: width,
            wrapperWidth: d.wrapper.clientWidth};
  }

  function patchDisplay(cm, from, to, intact, updateNumbersFrom) {
    var dims = getDimensions(cm);
    var display = cm.display, lineNumbers = cm.options.lineNumbers;
    // IE does bad things to nodes when .innerHTML = "" is used on a parent
    // we still need widgets and markers intact to add back to the new content later
    if (!intact.length && !ie && (!webkit || !cm.display.currentWheelTarget))
      removeChildren(display.lineDiv);
    var container = display.lineDiv, cur = container.firstChild;

    function rm(node) {
      var next = node.nextSibling;
      if (webkit && mac && cm.display.currentWheelTarget == node) {
        node.style.display = "none";
        node.lineObj = null;
      } else {
        container.removeChild(node);
      }
      return next;
    }

    var nextIntact = intact.shift(), lineNo = from;
    cm.view.doc.iter(from, to, function(line) {
      if (nextIntact && nextIntact.to == lineNo) nextIntact = intact.shift();
      if (lineIsHidden(line)) {
        if (line.height != 0) updateLineHeight(line, 0);
      } else if (nextIntact && nextIntact.from <= lineNo && nextIntact.to > lineNo) {
        // This line is intact. Skip to the actual node. Update its
        // line number if needed.
        while (cur.lineObj != line) cur = rm(cur);
        if (lineNumbers && updateNumbersFrom <= lineNo && cur.lineNumber)
          setTextContent(cur.lineNumber, lineNumberFor(cm.options, lineNo));
        cur = cur.nextSibling;
      } else {
        // This line needs to be generated.
        var lineNode = buildLineElement(cm, line, lineNo, dims);
        container.insertBefore(lineNode, cur);
        lineNode.lineObj = line;
      }
      ++lineNo;
    });
    while (cur) cur = rm(cur);
  }

  function buildLineElement(cm, line, lineNo, dims) {
    var lineElement = lineContent(cm, line);
    var markers = line.gutterMarkers, display = cm.display;

    if (!cm.options.lineNumbers && !markers && !line.bgClass && !line.wrapClass &&
        (!line.widgets || !line.widgets.length)) return lineElement;

    // Lines with gutter elements or a background class need
    // to be wrapped again, and have the extra elements added
    // to the wrapper div

    var wrap = elt("div", null, line.wrapClass, "position: relative");
    if (cm.options.lineNumbers || markers) {
      var gutterWrap = wrap.appendChild(elt("div", null, null, "position: absolute; left: " +
                                            dims.fixedPos + "px"));
      wrap.alignable = [gutterWrap];
      if (cm.options.lineNumbers && (!markers || !markers["CodeMirror-linenumbers"]))
        wrap.lineNumber = gutterWrap.appendChild(
          elt("div", lineNumberFor(cm.options, lineNo),
              "CodeMirror-linenumber CodeMirror-gutter-elt",
              "left: " + dims.gutterLeft["CodeMirror-linenumbers"] + "px; width: "
              + 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"));
        }
    }
    // Kludge to make sure the styled element lies behind the selection (by z-index)
    if (line.bgClass)
      wrap.appendChild(elt("div", "\u00a0", line.bgClass + " CodeMirror-linebackground"));
    wrap.appendChild(lineElement);
    if (line.widgets)
      for (var i = 0, ws = line.widgets; i < ws.length; ++i) {
        var widget = ws[i], node = elt("div", [widget.node], "CodeMirror-linewidget");
        node.widget = widget;
        if (widget.noHScroll) {
          (wrap.alignable || (wrap.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";
        }
        if (widget.above)
          wrap.insertBefore(node, cm.options.lineNumbers && line.height != 0 ? gutterWrap : lineElement);
        else
          wrap.appendChild(node);
      }

    if (ie_lt8) wrap.style.zIndex = 2;
    return wrap;
  }

  // SELECTION / CURSOR

  function updateSelection(cm) {
    var display = cm.display;
    var collapsed = posEq(cm.view.sel.from, cm.view.sel.to);
    if (collapsed || cm.options.showCursorWhenSelecting)
      updateSelectionCursor(cm);
    else
      display.cursor.style.display = display.otherCursor.style.display = "none";
    if (!collapsed)
      updateSelectionRange(cm);
    else
      display.selectionDiv.style.display = "none";

    // Move the hidden textarea near the cursor to prevent scrolling artifacts
    var headPos = cursorCoords(cm, cm.view.sel.head, "div");
    var wrapOff = display.wrapper.getBoundingClientRect(), lineOff = display.lineDiv.getBoundingClientRect();
    display.inputDiv.style.top = Math.max(0, Math.min(display.wrapper.clientHeight - 10,
                                                      headPos.top + lineOff.top - wrapOff.top)) + "px";
    display.inputDiv.style.left = Math.max(0, Math.min(display.wrapper.clientWidth - 10,
                                                       headPos.left + lineOff.left - wrapOff.left)) + "px";
  }

  // No selection, plain cursor
  function updateSelectionCursor(cm) {
    var display = cm.display, pos = cursorCoords(cm, cm.view.sel.head, "div");
    display.cursor.style.left = pos.left + "px";
    display.cursor.style.top = pos.top + "px";
    display.cursor.style.height = Math.max(0, pos.bottom - pos.top) * cm.options.cursorHeight + "px";
    display.cursor.style.display = "";

    if (pos.other) {
      display.otherCursor.style.display = "";
      display.otherCursor.style.left = pos.other.left + "px";
      display.otherCursor.style.top = pos.other.top + "px";
      display.otherCursor.style.height = (pos.other.bottom - pos.other.top) * .85 + "px";
    } else { display.otherCursor.style.display = "none"; }
  }

  // Highlight selection
  function updateSelectionRange(cm) {
    var display = cm.display, doc = cm.view.doc, sel = cm.view.sel;
    var fragment = document.createDocumentFragment();
    var clientWidth = display.lineSpace.offsetWidth, pl = paddingLeft(cm.display);

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

    function drawForLine(line, fromArg, toArg, retTop) {
      var lineObj = getLine(doc, line);
      var lineLen = lineObj.text.length, rVal = retTop ? Infinity : -Infinity;
      function coords(ch) {
        return charCoords(cm, {line: line, ch: ch}, "div", lineObj);
      }

      iterateBidiSections(getOrder(lineObj), fromArg || 0, toArg == null ? lineLen : toArg, function(from, to, dir) {
        var leftPos = coords(dir == "rtl" ? to - 1 : from);
        var rightPos = coords(dir == "rtl" ? from : to - 1);
        var left = leftPos.left, right = rightPos.right;
        if (rightPos.top - leftPos.top > 3) { // Different lines, draw top part
          add(left, leftPos.top, null, leftPos.bottom);
          left = pl;
          if (leftPos.bottom < rightPos.top) add(left, leftPos.bottom, null, rightPos.top);
        }
        if (toArg == null && to == lineLen) right = clientWidth;
        if (fromArg == null && from == 0) left = pl;
        rVal = retTop ? Math.min(rightPos.top, rVal) : Math.max(rightPos.bottom, rVal);
        if (left < pl + 1) left = pl;
        add(left, rightPos.top, right - left, rightPos.bottom);
      });
      return rVal;
    }

    if (sel.from.line == sel.to.line) {
      drawForLine(sel.from.line, sel.from.ch, sel.to.ch);
    } else {
      var fromObj = getLine(doc, sel.from.line);
      var cur = fromObj, merged, path = [sel.from.line, sel.from.ch], singleLine;
      while (merged = collapsedSpanAtEnd(cur)) {
        var found = merged.find();
        path.push(found.from.ch, found.to.line, found.to.ch);
        if (found.to.line == sel.to.line) {
          path.push(sel.to.ch);
          singleLine = true;
          break;
        }
        cur = getLine(doc, found.to.line);
      }

      // This is a single, merged line
      if (singleLine) {
        for (var i = 0; i < path.length; i += 3)
          drawForLine(path[i], path[i+1], path[i+2]);
      } else {
        var middleTop, middleBot, toObj = getLine(doc, sel.to.line);
        if (sel.from.ch)
          // Draw the first line of selection.
          middleTop = drawForLine(sel.from.line, sel.from.ch, null, false);
        else
          // Simply include it in the middle block.
          middleTop = heightAtLine(cm, fromObj) - display.viewOffset;

        if (!sel.to.ch)
          middleBot = heightAtLine(cm, toObj) - display.viewOffset;
        else
          middleBot = drawForLine(sel.to.line, collapsedSpanAtStart(toObj) ? null : 0, sel.to.ch, true);

        if (middleTop < middleBot) add(pl, middleTop, null, middleBot);
      }
    }

    removeChildrenAndAdd(display.selectionDiv, fragment);
    display.selectionDiv.style.display = "";
  }

  // Cursor-blinking
  function restartBlink(cm) {
    var display = cm.display;
    clearInterval(display.blinker);
    var on = true;
    display.cursor.style.visibility = display.otherCursor.style.visibility = "";
    display.blinker = setInterval(function() {
      if (!display.cursor.offsetHeight) return;
      display.cursor.style.visibility = display.otherCursor.style.visibility = (on = !on) ? "" : "hidden";
    }, cm.options.cursorBlinkRate);
  }

  // HIGHLIGHT WORKER

  function startWorker(cm, time) {
    if (cm.view.frontier < cm.display.showingTo)
      cm.view.highlight.set(time, bind(highlightWorker, cm));
  }

  function highlightWorker(cm) {
    var view = cm.view, doc = view.doc;
    if (view.frontier >= cm.display.showingTo) return;
    var end = +new Date + cm.options.workTime;
    var state = copyState(view.mode, getStateBefore(cm, view.frontier));
    var changed = [], prevChange;
    doc.iter(view.frontier, Math.min(doc.size, cm.display.showingTo + 500), function(line) {
      if (view.frontier >= cm.display.showingFrom) { // Visible
        if (highlightLine(cm, line, state) && view.frontier >= cm.display.showingFrom) {
          if (prevChange && prevChange.end == view.frontier) prevChange.end++;
          else changed.push(prevChange = {start: view.frontier, end: view.frontier + 1});
        }
        line.stateAfter = copyState(view.mode, state);
      } else {
        processLine(cm, line, state);
        line.stateAfter = view.frontier % 5 == 0 ? copyState(view.mode, state) : null;
      }
      ++view.frontier;
      if (+new Date > end) {
        startWorker(cm, cm.options.workDelay);
        return true;
      }
    });
    if (changed.length)
      operation(cm, function() {
        for (var i = 0; i < changed.length; ++i)
          regChange(this, changed[i].start, changed[i].end);
      })();
  }

  // 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) {
    var minindent, minline, doc = cm.view.doc;
    for (var search = n, lim = n - 100; search > lim; --search) {
      if (search == 0) return 0;
      var line = getLine(doc, search-1);
      if (line.stateAfter) return search;
      var indented = countColumn(line.text, null, cm.options.tabSize);
      if (minline == null || minindent > indented) {
        minline = search - 1;
        minindent = indented;
      }
    }
    return minline;
  }

  function getStateBefore(cm, n) {
    var view = cm.view;
    var pos = findStartLine(cm, n), state = pos && getLine(view.doc, pos-1).stateAfter;
    if (!state) state = startState(view.mode);
    else state = copyState(view.mode, state);
    view.doc.iter(pos, n, function(line) {
      processLine(cm, line, state);
      var save = pos == n - 1 || pos % 5 == 0 || pos >= view.showingFrom && pos < view.showingTo;
      line.stateAfter = save ? copyState(view.mode, state) : null;
      ++pos;
    });
    return state;
  }

  // POSITION MEASUREMENT
  
  function paddingTop(display) {return display.lineSpace.offsetTop;}
  function paddingLeft(display) {
    var e = removeChildrenAndAdd(display.measure, elt("pre")).appendChild(elt("span", "x"));
    return e.offsetLeft;
  }

  function measureChar(cm, line, ch, data) {
    var data = data || measureLine(cm, line), dir = -1;
    for (var pos = ch;; pos += dir) {
      var r = data[pos];
      if (r) break;
      if (dir < 0 && pos == 0) dir = 1;
    }
    return {left: pos < ch ? r.right : r.left,
            right: pos > ch ? r.left : r.right,
            top: r.top, bottom: r.bottom};
  }

  function measureLine(cm, line) {
    // First look in the cache
    var display = cm.display, cache = cm.display.measureLineCache;
    for (var i = 0; i < cache.length; ++i) {
      var memo = cache[i];
      if (memo.text == line.text && memo.markedSpans == line.markedSpans &&
          display.scroller.clientWidth == memo.width)
        return memo.measure;
    }
    
    var measure = measureLineInner(cm, line);
    // Store result in the cache
    var memo = {text: line.text, width: display.scroller.clientWidth,
                markedSpans: line.markedSpans, measure: measure};
    if (cache.length == 16) cache[++display.measureLineCachePos % 16] = memo;
    else cache.push(memo);
    return measure;
  }

  function measureLineInner(cm, line) {
    var display = cm.display, measure = emptyArray(line.text.length);
    var pre = lineContent(cm, line, measure);

    // IE does not cache element positions of inline elements between
    // calls to getBoundingClientRect. This makes the loop below,
    // which gathers the positions of all the characters on the line,
    // do an amount of layout work quadratic to the number of
    // characters. When line wrapping is off, we try to improve things
    // by first subdividing the line into a bunch of inline blocks, so
    // that IE can reuse most of the layout information from caches
    // for those blocks. This does interfere with line wrapping, so it
    // doesn't work when wrapping is on, but in that case the
    // situation is slightly better, since IE does cache line-wrapping
    // information and only recomputes per-line.
    if (ie && !ie_lt8 && !cm.options.lineWrapping && pre.childNodes.length > 100) {
      var fragment = document.createDocumentFragment();
      var chunk = 10, n = pre.childNodes.length;
      for (var i = 0, chunks = Math.ceil(n / chunk); i < chunks; ++i) {
        var wrap = elt("div", null, null, "display: inline-block");
        for (var j = 0; j < chunk && n; ++j) {
          wrap.appendChild(pre.firstChild);
          --n;
        }
        fragment.appendChild(wrap);
      }
      pre.appendChild(fragment);
    }

    removeChildrenAndAdd(display.measure, pre);

    var outer = display.lineDiv.getBoundingClientRect();
    var vranges = [], data = emptyArray(line.text.length), maxBot = pre.offsetHeight;
    for (var i = 0, cur; i < measure.length; ++i) if (cur = measure[i]) {
      var size = cur.getBoundingClientRect();
      var top = Math.max(0, size.top - outer.top), bot = Math.min(size.bottom - outer.top, maxBot);
      for (var j = 0; j < vranges.length; j += 2) {
        var rtop = vranges[j], rbot = vranges[j+1];
        if (rtop > bot || rbot < top) continue;
        if (rtop <= top && rbot >= bot ||
            top <= rtop && bot >= rbot ||
            Math.min(bot, rbot) - Math.max(top, rtop) >= (bot - top) >> 1) {
          vranges[j] = Math.min(top, rtop);
          vranges[j+1] = Math.max(bot, rbot);
          break;
        }
      }
      if (j == vranges.length) vranges.push(top, bot);
      data[i] = {left: size.left - outer.left, right: size.right - outer.left, top: j};
    }
    for (var i = 0, cur; i < data.length; ++i) if (cur = data[i]) {
      var vr = cur.top;
      cur.top = vranges[vr]; cur.bottom = vranges[vr+1];
    }
    return data;
  }

  function clearCaches(cm) {
    cm.display.measureLineCache.length = cm.display.measureLineCachePos = 0;
    cm.display.cachedCharWidth = cm.display.cachedTextHeight = null;
    cm.view.maxLineChanged = true;
  }

  // Context is one of "line", "div" (display.lineDiv), "local"/null (editor), or "page"
  function intoCoordSystem(cm, lineObj, rect, context) {
    if (lineObj.widgets) for (var i = 0; i < lineObj.widgets.length; ++i) if (lineObj.widgets[i].above) {
      var size = lineObj.widgets[i].node.offsetHeight;
      rect.top += size; rect.bottom += size;
    }
    if (context == "line") return rect;
    if (!context) context = "local";
    var yOff = heightAtLine(cm, lineObj);
    if (context != "local") yOff -= cm.display.viewOffset;
    if (context == "page") {
      var lOff = cm.display.lineSpace.getBoundingClientRect();
      yOff += lOff.top + (window.pageYOffset || (document.documentElement || document.body).scrollTop);
      var xOff = lOff.left + (window.pageXOffset || (document.documentElement || document.body).scrollLeft);
      rect.left += xOff; rect.right += xOff;
    }
    rect.top += yOff; rect.bottom += yOff;
    return rect;
  }

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

  function cursorCoords(cm, pos, context, lineObj, measurement) {
    lineObj = lineObj || getLine(cm.view.doc, pos.line);
    if (!measurement) measurement = measureLine(cm, lineObj);
    function get(ch, right) {
      var m = measureChar(cm, lineObj, ch, measurement);
      if (right) m.left = m.right; else m.right = m.left;
      return intoCoordSystem(cm, lineObj, m, context);
    }
    var order = getOrder(lineObj), ch = pos.ch;
    if (!order) return get(ch);
    var main, other, linedir = order[0].level;
    for (var i = 0; i < order.length; ++i) {
      var part = order[i], rtl = part.level % 2, nb, here;
      if (part.from < ch && part.to > ch) return get(ch, rtl);
      var left = rtl ? part.to : part.from, right = rtl ? part.from : part.to;
      if (left == ch) {
        // Opera and IE return bogus offsets and widths for edges
        // where the direction flips, but only for the side with the
        // lower level. So we try to use the side with the higher
        // level.
        if (i && part.level < (nb = order[i-1]).level) here = get(nb.level % 2 ? nb.from : nb.to - 1, true);
        else here = get(rtl && part.from != part.to ? ch - 1 : ch);
        if (rtl == linedir) main = here; else other = here;
      } else if (right == ch) {
        var nb = i < order.length - 1 && order[i+1];
        if (!rtl && nb && nb.from == nb.to) continue;
        if (nb && part.level < nb.level) here = get(nb.level % 2 ? nb.to - 1 : nb.from);
        else here = get(rtl ? ch : ch - 1, true);
        if (rtl == linedir) main = here; else other = here;
      }
    }
    if (linedir && !ch) other = get(order[0].to - 1);
    if (!main) return other;
    if (other) main.other = other;
    return main;
  }

  // Coords must be lineSpace-local
  function coordsChar(cm, x, y) {
    var doc = cm.view.doc;
    y += cm.display.viewOffset;
    if (y < 0) return {line: 0, ch: 0, outside: true};
    var lineNo = lineAtHeight(doc, y);
    if (lineNo >= doc.size) return {line: doc.size - 1, ch: getLine(doc, doc.size - 1).text.length};
    if (x < 0) x = 0;

    for (;;) {
      var lineObj = getLine(doc, lineNo);
      var found = coordsCharInner(cm, lineObj, lineNo, x, y);
      var merged = collapsedSpanAtEnd(lineObj);
      if (merged && found.ch == lineRight(lineObj))
        lineNo = merged.find().to.line;
      else
        return found;
    }
  }

  function coordsCharInner(cm, lineObj, lineNo, x, y) {
    var innerOff = y - heightAtLine(cm, lineObj);
    var wrongLine = false, cWidth = cm.display.wrapper.clientWidth;
    var measurement = measureLine(cm, lineObj);

    function getX(ch) {
      var sp = cursorCoords(cm, {line: lineNo, ch: ch}, "line",
                            lineObj, measurement);
      wrongLine = true;
      if (innerOff > sp.bottom) return Math.max(0, sp.left - cWidth);
      else if (innerOff < sp.top) return sp.left + cWidth;
      else wrongLine = false;
      return sp.left;
    }

    var bidi = getOrder(lineObj), dist = lineObj.text.length;
    var from = lineLeft(lineObj), to = lineRight(lineObj);
    var fromX = paddingLeft(cm.display), toX = getX(to);

    if (x > toX) return {line: lineNo, ch: to, outside: wrongLine};
    // Do a binary search between these bounds.
    for (;;) {
      if (bidi ? to == from || to == moveVisually(lineObj, from, 1) : to - from <= 1) {
        var after = x - fromX < toX - x, ch = after ? from : to;
        while (isExtendingChar.test(lineObj.text.charAt(ch))) ++ch;
        return {line: lineNo, ch: ch, after: after, outside: wrongLine};
      }
      var step = Math.ceil(dist / 2), middle = from + step;
      if (bidi) {
        middle = from;
        for (var i = 0; i < step; ++i) middle = moveVisually(lineObj, middle, 1);
      }
      var middleX = getX(middle);
      if (middleX > x) {to = middle; toX = middleX; if (wrongLine) toX += 1000; dist -= step;}
      else {from = middle; fromX = middleX; dist = step;}
    }
  }

  var measureText;
  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;
  }

  function charWidth(display) {
    if (display.cachedCharWidth != null) return display.cachedCharWidth;
    var anchor = elt("span", "x");
    var pre = elt("pre", [anchor]);
    removeChildrenAndAdd(display.measure, pre);
    var width = anchor.offsetWidth;
    if (width > 2) display.cachedCharWidth = width;
    return width || 10;
  }

  // OPERATIONS

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

  function startOperation(cm) {
    if (cm.curOp) ++cm.curOp.depth;
    else cm.curOp = {
      // Nested operations delay update until the outermost one
      // finishes.
      depth: 1,
      // An array of ranges of lines that have to be updated. See
      // updateDisplay.
      changes: [],
      delayedCallbacks: [],
      updateInput: null,
      userSelChange: null,
      textChanged: null,
      selectionChanged: false,
      updateMaxLine: false,
      id: ++cm.nextOpId
    };
  }

  function endOperation(cm) {
    var op = cm.curOp;
    if (--op.depth) return;
    cm.curOp = null;
    var view = cm.view, display = cm.display;
    if (op.updateMaxLine) computeMaxLength(view);
    if (view.maxLineChanged && !cm.options.lineWrapping) {
      var width = measureChar(cm, view.maxLine, view.maxLine.text.length).right;
      display.sizer.style.minWidth = (width + 3 + scrollerCutOff) + "px";
      view.maxLineChanged = false;
    }
    var newScrollPos, updated;
    if (op.selectionChanged) {
      var coords = cursorCoords(cm, view.sel.head);
      newScrollPos = calculateScrollPos(cm, coords.left, coords.top, coords.left, coords.bottom);
    }
    if (op.changes.length || newScrollPos && newScrollPos.scrollTop != null)
      updated = updateDisplay(cm, op.changes, newScrollPos && newScrollPos.scrollTop);
    if (!updated && op.selectionChanged) updateSelection(cm);
    if (newScrollPos) scrollCursorIntoView(cm);
    if (op.selectionChanged) restartBlink(cm);

    if (view.focused && op.updateInput)
      resetInput(cm, op.userSelChange);

    if (op.textChanged)
      signal(cm, "change", cm, op.textChanged);
    if (op.selectionChanged) signal(cm, "cursorActivity", cm);
    for (var i = 0; i < op.delayedCallbacks.length; ++i) op.delayedCallbacks[i](cm);
  }

  // Wraps a function in an operation. Returns the wrapped function.
  function operation(cm1, f) {
    return function() {
      var cm = cm1 || this;
      startOperation(cm);
      try {var result = f.apply(cm, arguments);}
      finally {endOperation(cm);}
      return result;
    };
  }

  function regChange(cm, from, to, lendiff) {
    cm.curOp.changes.push({from: from, to: to, diff: lendiff});
  }

  // INPUT HANDLING

  function slowPoll(cm) {
    if (cm.view.pollingFast) return;
    cm.display.poll.set(cm.options.pollInterval, function() {
      readInput(cm);
      if (cm.view.focused) slowPoll(cm);
    });
  }

  function fastPoll(cm) {
    var missed = false;
    cm.display.pollingFast = true;
    function p() {
      var changed = readInput(cm);
      if (!changed && !missed) {missed = true; cm.display.poll.set(60, p);}
      else {cm.display.pollingFast = false; slowPoll(cm);}
    }
    cm.display.poll.set(20, p);
  }

  // prevInput is a hack to work with IME. If we reset the textarea
  // on every change, that breaks IME. So we look for changes
  // compared to the previous content instead. (Modern browsers have
  // events that indicate IME taking place, but these are not widely
  // supported or compatible enough yet to rely on.)
  function readInput(cm) {
    var input = cm.display.input, prevInput = cm.display.prevInput, view = cm.view, sel = view.sel;
    if (!view.focused || hasSelection(input) || isReadOnly(cm)) return false;
    var text = input.value;
    if (text == prevInput && posEq(sel.from, sel.to)) return false;
    startOperation(cm);
    view.sel.shift = false;
    var same = 0, l = Math.min(prevInput.length, text.length);
    while (same < l && prevInput[same] == text[same]) ++same;
    var from = sel.from, to = sel.to;
    if (same < prevInput.length)
      from = {line: from.line, ch: from.ch - (prevInput.length - same)};
    else if (view.overwrite && posEq(from, to) && !cm.display.pasteIncoming)
      to = {line: to.line, ch: Math.min(getLine(cm.view.doc, to.line).text.length, to.ch + (text.length - same))};
    var updateInput = cm.curOp.updateInput;
    updateDoc(cm, from, to, splitLines(text.slice(same)), "end",
              cm.display.pasteIncoming ? "paste" : "input", {from: from, to: to});
    cm.curOp.updateInput = updateInput;
    if (text.length > 1000) input.value = cm.display.prevInput = "";
    else cm.display.prevInput = text;
    endOperation(cm);
    cm.display.pasteIncoming = false;
    return true;
  }

  function resetInput(cm, user) {
    var view = cm.view, minimal, selected;
    if (!posEq(view.sel.from, view.sel.to)) {
      cm.display.prevInput = "";
      minimal = hasCopyEvent &&
        (view.sel.to.line - view.sel.from.line > 100 || (selected = cm.getSelection()).length > 1000);
      if (minimal) cm.display.input.value = "-";
      else cm.display.input.value = selected || cm.getSelection();
      if (view.focused) selectInput(cm.display.input);
    } else if (user) cm.display.prevInput = cm.display.input.value = "";
    cm.display.inaccurateSelection = minimal;
  }

  function focusInput(cm) {
    if (cm.options.readOnly != "nocursor" && (ie || document.activeElement != cm.display.input))
      cm.display.input.focus();
  }

  function isReadOnly(cm) {
    return cm.options.readOnly || cm.view.cantEdit;
  }

  // EVENT HANDLERS

  function registerEventHandlers(cm) {
    var d = cm.display;
    on(d.scroller, "mousedown", operation(cm, onMouseDown));
    on(d.scroller, "dblclick", operation(cm, e_preventDefault));
    on(d.lineSpace, "selectstart", function(e) {
      if (!mouseEventInWidget(d, e)) e_preventDefault(e);
    });
    // Gecko browsers fire contextmenu *after* opening the menu, at
    // which point we can't mess with it anymore. Context menu is
    // handled in onMouseDown for Gecko.
    if (!gecko) on(d.scroller, "contextmenu", function(e) {onContextMenu(cm, e);});

    on(d.scroller, "scroll", function() {
      setScrollTop(cm, d.scroller.scrollTop);
      setScrollLeft(cm, d.scroller.scrollLeft, true);
      signal(cm, "scroll", cm);
    });
    on(d.scrollbarV, "scroll", function() {
      setScrollTop(cm, d.scrollbarV.scrollTop);
    });
    on(d.scrollbarH, "scroll", function() {
      setScrollLeft(cm, d.scrollbarH.scrollLeft);
    });

    on(d.scroller, "mousewheel", function(e){onScrollWheel(cm, e);});
    on(d.scroller, "DOMMouseScroll", function(e){onScrollWheel(cm, e);});

    function reFocus() { if (cm.view.focused) setTimeout(bind(focusInput, cm), 0); }
    on(d.scrollbarH, "mousedown", reFocus);
    on(d.scrollbarV, "mousedown", reFocus);
    // Prevent wrapper from ever scrolling
    on(d.wrapper, "scroll", function() { d.wrapper.scrollTop = d.wrapper.scrollLeft = 0; });
    on(window, "resize", function resizeHandler() {
      // Might be a text scaling operation, clear size caches.
      d.cachedCharWidth = d.cachedTextHeight = null;
      clearCaches(cm);
      if (d.wrapper.parentNode) updateDisplay(cm, true);
      else off(window, "resize", resizeHandler);
    });

    on(d.input, "keyup", operation(cm, function(e) {
      if (cm.options.onKeyEvent && cm.options.onKeyEvent(cm, addStop(e))) return;
      if (e_prop(e, "keyCode") == 16) cm.view.sel.shift = false;
    }));
    on(d.input, "input", bind(fastPoll, cm));
    on(d.input, "keydown", operation(cm, onKeyDown));
    on(d.input, "keypress", operation(cm, onKeyPress));
    on(d.input, "focus", bind(onFocus, cm));
    on(d.input, "blur", bind(onBlur, cm));

    function drag_(e) {
      if (cm.options.onDragEvent && cm.options.onDragEvent(cm, addStop(e))) return;
      e_stop(e);
    }
    if (cm.options.dragDrop) {
      on(d.scroller, "dragstart", function(e){onDragStart(cm, e);});
      on(d.scroller, "dragenter", drag_);
      on(d.scroller, "dragover", drag_);
      on(d.scroller, "drop", operation(cm, onDrop));
    }
    on(d.scroller, "paste", function(){focusInput(cm); fastPoll(cm);});
    on(d.input, "paste", function() {
      d.pasteIncoming = true;
      fastPoll(cm);
    });

    function prepareCopy() {
      if (d.inaccurateSelection) {
        d.prevInput = "";
        d.inaccurateSelection = false;
        d.input.value = cm.getSelection();
        selectInput(d.input);
      }
    }
    on(d.input, "cut", prepareCopy);
    on(d.input, "copy", prepareCopy);

    // Needed to handle Tab key in KHTML
    if (khtml) on(d.sizer, "mouseup", function() {
        if (document.activeElement == d.input) d.input.blur();
        focusInput(cm);
    });
  }

  function mouseEventInWidget(display, e) {
    for (var n = e_target(e); n != display.wrapper; n = n.parentNode)
      if (/\bCodeMirror-(?:line)?widget\b/.test(n.className) ||
          n.parentNode == display.sizer && n != display.mover) return true;
  }

  function posFromMouse(cm, e, liberal) {
    var display = cm.display;
    if (!liberal) {
      var target = e_target(e);
      if (target == display.scrollbarH || target == display.scrollbarH.firstChild ||
          target == display.scrollbarV || target == display.scrollbarV.firstChild ||
          target == display.scrollbarFiller) return null;
    }
    var x, y, space = display.lineSpace.getBoundingClientRect();
    // Fails unpredictably on IE[67] when mouse is dragged around quickly.
    try { x = e.clientX; y = e.clientY; } catch (e) { return null; }
    return coordsChar(cm, x - space.left, y - space.top);
  }

  var lastClick, lastDoubleClick;
  function onMouseDown(e) {
    var cm = this, display = cm.display, view = cm.view, sel = view.sel, doc = view.doc;
    sel.shift = e_prop(e, "shiftKey");

    if (mouseEventInWidget(display, e)) {
      if (!webkit) {
        display.scroller.draggable = false;
        setTimeout(function(){display.scroller.draggable = true;}, 100);
      }
      return;
    }
    if (clickInGutter(cm, e)) return;
    var start = posFromMouse(cm, e);

    switch (e_button(e)) {
    case 3:
      if (gecko) onContextMenu.call(cm, cm, e);
      return;
    case 2:
      if (start) extendSelection(cm, start);
      setTimeout(bind(focusInput, cm), 20);
      e_preventDefault(e);
      return;
    }
    // For button 1, if it was clicked inside the editor
    // (posFromMouse returning non-null), we have to adjust the
    // selection.
    if (!start) {if (e_target(e) == display.scroller) e_preventDefault(e); return;}

    if (!view.focused) onFocus(cm);

    var now = +new Date, type = "single";
    if (lastDoubleClick && lastDoubleClick.time > now - 400 && posEq(lastDoubleClick.pos, start)) {
      type = "triple";
      e_preventDefault(e);
      setTimeout(bind(focusInput, cm), 20);
      selectLine(cm, start.line);
    } else if (lastClick && lastClick.time > now - 400 && posEq(lastClick.pos, start)) {
      type = "double";
      lastDoubleClick = {time: now, pos: start};
      e_preventDefault(e);
      var word = findWordAt(getLine(doc, start.line).text, start);
      extendSelection(cm, word.from, word.to);
    } else { lastClick = {time: now, pos: start}; }

    var last = start;
    if (cm.options.dragDrop && dragAndDrop && !isReadOnly(cm) && !posEq(sel.from, sel.to) &&
        !posLess(start, sel.from) && !posLess(sel.to, start) && type == "single") {
      var dragEnd = operation(cm, function(e2) {
        if (webkit) display.scroller.draggable = false;
        view.draggingText = false;
        off(document, "mouseup", dragEnd);
        off(display.scroller, "drop", dragEnd);
        if (Math.abs(e.clientX - e2.clientX) + Math.abs(e.clientY - e2.clientY) < 10) {
          e_preventDefault(e2);
          extendSelection(cm, start);
          focusInput(cm);
        }
      });
      // Let the drag handler handle this.
      if (webkit) display.scroller.draggable = true;
      view.draggingText = dragEnd;
      // IE's approach to draggable
      if (display.scroller.dragDrop) display.scroller.dragDrop();
      on(document, "mouseup", dragEnd);
      on(display.scroller, "drop", dragEnd);
      return;
    }
    e_preventDefault(e);
    if (type == "single") extendSelection(cm, clipPos(doc, start));

    var startstart = sel.from, startend = sel.to;

    function doSelect(cur) {
      if (type == "single") {
        extendSelection(cm, clipPos(doc, start), cur);
        return;
      }

      startstart = clipPos(doc, startstart);
      startend = clipPos(doc, startend);
      if (type == "double") {
        var word = findWordAt(getLine(doc, cur.line).text, cur);
        if (posLess(cur, startstart)) extendSelection(cm, word.from, startend);
        else extendSelection(cm, startstart, word.to);
      } else if (type == "triple") {
        if (posLess(cur, startstart)) extendSelection(cm, startend, clipPos(doc, {line: cur.line, ch: 0}));
        else extendSelection(cm, startstart, clipPos(doc, {line: cur.line + 1, ch: 0}));
      }
    }

    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);
      if (!cur) return;
      if (!posEq(cur, last)) {
        if (!view.focused) onFocus(cm);
        last = cur;
        doSelect(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) {
      counter = Infinity;
      var cur = posFromMouse(cm, e);
      if (cur) doSelect(cur);
      e_preventDefault(e);
      focusInput(cm);
      off(document, "mousemove", move);
      off(document, "mouseup", up);
    }

    var move = operation(cm, function(e) {
      if (!ie && !e_button(e)) done(e);
      else extend(e);
    });
    var up = operation(cm, done);
    on(document, "mousemove", move);
    on(document, "mouseup", up);
  }

  function onDrop(e) {
    var cm = this;
    if (cm.options.onDragEvent && cm.options.onDragEvent(cm, addStop(e))) return;
    e_preventDefault(e);
    var pos = posFromMouse(cm, e, true), files = e.dataTransfer.files;
    if (!pos || isReadOnly(cm)) return;
    if (files && files.length && window.FileReader && window.File) {
      var n = files.length, text = Array(n), read = 0;
      var loadFile = function(file, i) {
        var reader = new FileReader;
        reader.onload = function() {
          text[i] = reader.result;
          if (++read == n) {
            pos = clipPos(cm.view.doc, pos);
            operation(cm, function() {
              var end = replaceRange(cm, text.join(""), pos, pos, "paste");
              setSelection(cm, pos, end);
            })();
          }
        };
        reader.readAsText(file);
      };
      for (var i = 0; i < n; ++i) loadFile(files[i], i);
    } else {
      // Don't do a replace if the drop happened inside of the selected text.
      if (cm.view.draggingText && !(posLess(pos, cm.view.sel.from) || posLess(cm.view.sel.to, pos))) {
        cm.view.draggingText(e);
        if (ie) setTimeout(bind(focusInput, cm), 50);
        return;
      }
      try {
        var text = e.dataTransfer.getData("Text");
        if (text) {
          var curFrom = cm.view.sel.from, curTo = cm.view.sel.to;
          setSelection(cm, pos, pos);
          if (cm.view.draggingText) replaceRange(cm, "", curFrom, curTo, "paste");
          cm.replaceSelection(text, null, "paste");
          focusInput(cm);
          onFocus(cm);
        }
      }
      catch(e){}
    }
  }

  function clickInGutter(cm, e) {
    var display = cm.display;
    try { var mX = e.clientX, mY = e.clientY; }
    catch(e) { return false; }

    if (mX >= Math.floor(display.gutters.getBoundingClientRect().right)) return false;
    e_preventDefault(e);
    if (!hasHandler(cm, "gutterClick")) return true;

    var lineBox = display.lineDiv.getBoundingClientRect();
    if (mY > lineBox.bottom) return true;
    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.view.doc, mY);
        var gutter = cm.options.gutters[i];
        signalLater(cm, cm, "gutterClick", cm, line, gutter, e);
        break;
      }
    }
    return true;
  }

  function onDragStart(cm, e) {
    var txt = cm.getSelection();
    e.dataTransfer.setData("Text", txt);

    // 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)
      e.dataTransfer.setDragImage(elt('img'), 0, 0);
  }

  function setScrollTop(cm, val) {
    if (Math.abs(cm.view.scrollTop - val) < 2) return;
    cm.view.scrollTop = val;
    if (!gecko) updateDisplay(cm, [], val);
    if (cm.display.scroller.scrollTop != val) cm.display.scroller.scrollTop = val;
    if (cm.display.scrollbarV.scrollTop != val) cm.display.scrollbarV.scrollTop = val;
    if (gecko) updateDisplay(cm, []);
  }
  function setScrollLeft(cm, val, isScroller) {
    if (isScroller ? val == cm.view.scrollLeft : Math.abs(cm.view.scrollLeft - val) < 2) return;
    cm.view.scrollLeft = val;
    alignHorizontally(cm);
    if (cm.display.scroller.scrollLeft != val) cm.display.scroller.scrollLeft = val;
    if (cm.display.scrollbarH.scrollLeft != val) cm.display.scrollbarH.scrollLeft = val;
  }

  // Since the delta values reported on mouse wheel events are
  // unstandardized between browsers and even browser versions, and
  // generally horribly unpredictable, this code starts by measuring
  // the scroll effect that the first few mouse wheel events have,
  // and, from that, detects the way it can convert deltas to pixel
  // offsets afterwards.
  //
  // The reason we want to know the amount a wheel event will scroll
  // is that it gives us a chance to update the display before the
  // actual scrolling happens, reducing flickering.

  var wheelSamples = 0, wheelDX, wheelDY, wheelStartX, wheelStartY, 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 onScrollWheel(cm, 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;

    // 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) {
      for (var cur = e.target; cur != scroll; cur = cur.parentNode) {
        if (cur.lineObj) {
          cm.display.currentWheelTarget = cur;
          break;
        }
      }
    }

    var scroll = cm.display.scroller;
    // 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 && !opera && wheelPixelsPerUnit != null) {
      if (dy)
        setScrollTop(cm, Math.max(0, Math.min(scroll.scrollTop + dy * wheelPixelsPerUnit, scroll.scrollHeight - scroll.clientHeight)));
      setScrollLeft(cm, Math.max(0, Math.min(scroll.scrollLeft + dx * wheelPixelsPerUnit, scroll.scrollWidth - scroll.clientWidth)));
      e_preventDefault(e);
      wheelStartX = null; // Abort measurement, if in progress
      return;
    }

    if (dy && wheelPixelsPerUnit != null) {
      var pixels = dy * wheelPixelsPerUnit;
      var top = cm.view.scrollTop, bot = top + cm.display.wrapper.clientHeight;
      if (pixels < 0) top = Math.max(0, top + pixels - 50);
      else bot = Math.min(cm.view.doc.height, bot + pixels + 50);
      updateDisplay(cm, [], {top: top, bottom: bot});
    }

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

  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
    if (cm.display.pollingFast && readInput(cm)) cm.display.pollingFast = false;
    var view = cm.view, prevShift = view.sel.shift;
    try {
      if (isReadOnly(cm)) view.suppressEdits = true;
      if (dropShift) view.sel.shift = false;
      bound(cm);
    } catch(e) {
      if (e != Pass) throw e;
      return false;
    } finally {
      view.sel.shift = prevShift;
      view.suppressEdits = false;
    }
    return true;
  }

  function allKeyMaps(cm) {
    var maps = cm.view.keyMaps.slice(0);
    maps.push(cm.options.keyMap);
    if (cm.options.extraKeys) maps.unshift(cm.options.extraKeys);
    return maps;
  }

  var maybeTransition;
  function handleKeyBinding(cm, e) {
    // Handle auto keymap transitions
    var startMap = getKeyMap(cm.options.keyMap), next = startMap.auto;
    clearTimeout(maybeTransition);
    if (next && !isModifierKey(e)) maybeTransition = setTimeout(function() {
      if (getKeyMap(cm.options.keyMap) == startMap)
        cm.options.keyMap = (next.call ? next.call(null, cm) : next);
    }, 50);

    var name = keyNames[e_prop(e, "keyCode")], handled = false;
    var flipCtrlCmd = mac && (opera || qtwebkit);
    if (name == null || e.altGraphKey) return false;
    if (e_prop(e, "altKey")) name = "Alt-" + name;
    if (e_prop(e, flipCtrlCmd ? "metaKey" : "ctrlKey")) name = "Ctrl-" + name;
    if (e_prop(e, flipCtrlCmd ? "ctrlKey" : "metaKey")) name = "Cmd-" + name;

    var stopped = false;
    function stop() { stopped = true; }
    var keymaps = allKeyMaps(cm);

    if (e_prop(e, "shiftKey")) {
      handled = lookupKey("Shift-" + name, keymaps,
                          function(b) {return doHandleBinding(cm, b, true);}, stop)
        || lookupKey(name, keymaps, function(b) {
          if (typeof b == "string" && /^go[A-Z]/.test(b)) return doHandleBinding(cm, b);
        }, stop);
    } else {
      handled = lookupKey(name, keymaps,
                          function(b) { return doHandleBinding(cm, b); }, stop);
    }
    if (stopped) handled = false;
    if (handled) {
      e_preventDefault(e);
      restartBlink(cm);
      if (ie_lt9) { e.oldKeyCode = e.keyCode; e.keyCode = 0; }
    }
    return handled;
  }

  function handleCharBinding(cm, e, ch) {
    var handled = lookupKey("'" + ch + "'", allKeyMaps(cm),
                            function(b) { return doHandleBinding(cm, b, true); });
    if (handled) {
      e_preventDefault(e);
      restartBlink(cm);
    }
    return handled;
  }

  var lastStoppedKey = null;
  function onKeyDown(e) {
    var cm = this;
    if (!cm.view.focused) onFocus(cm);
    if (ie && e.keyCode == 27) { e.returnValue = false; }
    if (cm.options.onKeyEvent && cm.options.onKeyEvent(cm, addStop(e))) return;
    var code = e_prop(e, "keyCode");
    // IE does strange things with escape.
    cm.view.sel.shift = code == 16 || e_prop(e, "shiftKey");
    // First give onKeyEvent option a chance to handle this.
    var handled = handleKeyBinding(cm, e);
    if (opera) {
      lastStoppedKey = handled ? code : null;
      // Opera has no cut event... we try to at least catch the key combo
      if (!handled && code == 88 && !hasCopyEvent && e_prop(e, mac ? "metaKey" : "ctrlKey"))
        cm.replaceSelection("");
    }
  }

  function onKeyPress(e) {
    var cm = this;
    if (cm.options.onKeyEvent && cm.options.onKeyEvent(cm, addStop(e))) return;
    var keyCode = e_prop(e, "keyCode"), charCode = e_prop(e, "charCode");
    if (opera && keyCode == lastStoppedKey) {lastStoppedKey = null; e_preventDefault(e); return;}
    if (((opera && (!e.which || e.which < 10)) || khtml) && handleKeyBinding(cm, e)) return;
    var ch = String.fromCharCode(charCode == null ? keyCode : charCode);
    if (this.options.electricChars && this.view.mode.electricChars &&
        this.options.smartIndent && !isReadOnly(this) &&
        this.view.mode.electricChars.indexOf(ch) > -1)
      setTimeout(operation(cm, function() {indentLine(cm, cm.view.sel.to.line, "smart");}), 75);
    if (handleCharBinding(cm, e, ch)) return;
    fastPoll(cm);
  }

  function onFocus(cm) {
    if (cm.options.readOnly == "nocursor") return;
    if (!cm.view.focused) {
      signal(cm, "focus", cm);
      cm.view.focused = true;
      if (cm.display.scroller.className.search(/\bCodeMirror-focused\b/) == -1)
        cm.display.scroller.className += " CodeMirror-focused";
      resetInput(cm, true);
    }
    slowPoll(cm);
    restartBlink(cm);
  }
  function onBlur(cm) {
    if (cm.view.focused) {
      signal(cm, "blur", cm);
      cm.view.focused = false;
      cm.display.scroller.className = cm.display.scroller.className.replace(" CodeMirror-focused", "");
    }
    clearInterval(cm.display.blinker);
    setTimeout(function() {if (!cm.view.focused) cm.view.sel.shift = false;}, 150);
  }

  var detectingSelectAll;
  function onContextMenu(cm, e) {
    var display = cm.display, sel = cm.view.sel;
    var pos = posFromMouse(cm, e), scrollPos = display.scroller.scrollTop;
    if (!pos || opera) return; // Opera is difficult.
    if (posEq(sel.from, sel.to) || posLess(pos, sel.from) || !posLess(pos, sel.to))
      operation(cm, setSelection)(cm, pos, pos);

    var oldCSS = display.input.style.cssText;
    display.inputDiv.style.position = "absolute";
    display.input.style.cssText = "position: fixed; width: 30px; height: 30px; top: " + (e.clientY - 5) +
      "px; left: " + (e.clientX - 5) + "px; z-index: 1000; background: white; outline: none;" +
      "border-width: 0; outline: none; overflow: hidden; opacity: .05; filter: alpha(opacity=5);";
    focusInput(cm);
    resetInput(cm, true);
    // Adds "Select all" to context menu in FF
    if (posEq(sel.from, sel.to)) display.input.value = display.prevInput = " ";

    function rehide() {
      display.inputDiv.style.position = "relative";
      display.input.style.cssText = oldCSS;
      if (ie_lt9) display.scrollbarV.scrollTop = display.scroller.scrollTop = scrollPos;
      slowPoll(cm);

      // Try to detect the user choosing select-all 
      if (display.input.selectionStart != null) {
        clearTimeout(detectingSelectAll);
        var extval = display.input.value = " " + (posEq(sel.from, sel.to) ? "" : display.input.value), i = 0;
        display.prevInput = " ";
        display.input.selectionStart = 1; display.input.selectionEnd = extval.length;
        detectingSelectAll = setTimeout(function poll(){
          if (display.prevInput == " " && display.input.selectionStart == 0)
            operation(cm, commands.selectAll)(cm);
          else if (i++ < 10) detectingSelectAll = setTimeout(poll, 500);
          else resetInput(cm);
        }, 200);
      }
    }

    if (gecko) {
      e_stop(e);
      on(window, "mouseup", function mouseup() {
        off(window, "mouseup", mouseup);
        setTimeout(rehide, 20);
      });
    } else {
      setTimeout(rehide, 50);
    }
  }

  // UPDATING

  // Replace the range from from to to by the strings in newText.
  // Afterwards, set the selection to selFrom, selTo.
  function updateDoc(cm, from, to, newText, selUpdate, origin) {
    // Possibly split or suppress the update based on the presence
    // of read-only spans in its range.
    var split = sawReadOnlySpans &&
      removeReadOnlyRanges(cm.view.doc, from, to);
    if (split) {
      for (var i = split.length - 1; i >= 1; --i)
        updateDocInner(cm, split[i].from, split[i].to, [""], origin);
      if (split.length)
        return updateDocInner(cm, split[0].from, split[0].to, newText, selUpdate, origin);
    } else {
      return updateDocInner(cm, from, to, newText, selUpdate, origin);
    }
  }

  function updateDocInner(cm, from, to, newText, selUpdate, origin) {
    if (cm.view.suppressEdits) return;

    var view = cm.view, doc = view.doc, old = [];
    doc.iter(from.line, to.line + 1, function(line) {
      old.push(newHL(line.text, line.markedSpans));
    });
    var startSelFrom = view.sel.from, startSelTo = view.sel.to;
    var lines = updateMarkedSpans(hlSpans(old[0]), hlSpans(lst(old)), from.ch, to.ch, newText);
    var retval = updateDocNoUndo(cm, from, to, lines, selUpdate, origin);
    if (view.history) addChange(cm, from.line, newText.length, old, origin,
                                startSelFrom, startSelTo, view.sel.from, view.sel.to);
    return retval;
  }

  function unredoHelper(cm, type) {
    var doc = cm.view.doc, hist = cm.view.history;
    var set = (type == "undo" ? hist.done : hist.undone).pop();
    if (!set) return;
    var anti = {events: [], fromBefore: set.fromAfter, toBefore: set.toAfter,
                fromAfter: set.fromBefore, toAfter: set.toBefore};
    for (var i = set.events.length - 1; i >= 0; i -= 1) {
      hist.dirtyCounter += type == "undo" ? -1 : 1;
      var change = set.events[i];
      var replaced = [], end = change.start + change.added;
      doc.iter(change.start, end, function(line) { replaced.push(newHL(line.text, line.markedSpans)); });
      anti.events.push({start: change.start, added: change.old.length, old: replaced});
      var selPos = i ? null : {from: set.fromBefore, to: set.toBefore};
      updateDocNoUndo(cm, {line: change.start, ch: 0}, {line: end - 1, ch: getLine(doc, end-1).text.length},
                      change.old, selPos, type);
    }
    (type == "undo" ? hist.undone : hist.done).push(anti);
  }

  function updateDocNoUndo(cm, from, to, lines, selUpdate, origin) {
    var view = cm.view, doc = view.doc, display = cm.display;
    if (view.suppressEdits) return;

    var nlines = to.line - from.line, firstLine = getLine(doc, from.line), lastLine = getLine(doc, to.line);
    var recomputeMaxLength = false, checkWidthStart = from.line;
    if (!cm.options.lineWrapping) {
      checkWidthStart = lineNo(visualLine(doc, firstLine));
      doc.iter(checkWidthStart, to.line + 1, function(line) {
        if (lineLength(doc, line) == view.maxLineLength) {
          recomputeMaxLength = true;
          return true;
        }
      });
    }

    var lastHL = lst(lines), th = textHeight(display);

    // First adjust the line structure
    if (from.ch == 0 && to.ch == 0 && hlText(lastHL) == "") {
      // This is a whole-line replace. Treated specially to make
      // sure line objects move the way they are supposed to.
      var added = [];
      for (var i = 0, e = lines.length - 1; i < e; ++i)
        added.push(makeLine(hlText(lines[i]), hlSpans(lines[i]), th));
      updateLine(cm, lastLine, lastLine.text, hlSpans(lastHL));
      if (nlines) doc.remove(from.line, nlines, cm);
      if (added.length) doc.insert(from.line, added);
    } else if (firstLine == lastLine) {
      if (lines.length == 1) {
        updateLine(cm, firstLine, firstLine.text.slice(0, from.ch) + hlText(lines[0]) +
                   firstLine.text.slice(to.ch), hlSpans(lines[0]));
      } else {
        for (var added = [], i = 1, e = lines.length - 1; i < e; ++i)
          added.push(makeLine(hlText(lines[i]), hlSpans(lines[i]), th));
        added.push(makeLine(hlText(lastHL) + firstLine.text.slice(to.ch), hlSpans(lastHL), th));
        updateLine(cm, firstLine, firstLine.text.slice(0, from.ch) + hlText(lines[0]), hlSpans(lines[0]));
        doc.insert(from.line + 1, added);
      }
    } else if (lines.length == 1) {
      updateLine(cm, firstLine, firstLine.text.slice(0, from.ch) + hlText(lines[0]) +
                 lastLine.text.slice(to.ch), hlSpans(lines[0]));
      doc.remove(from.line + 1, nlines, cm);
    } else {
      var added = [];
      updateLine(cm, firstLine, firstLine.text.slice(0, from.ch) + hlText(lines[0]), hlSpans(lines[0]));
      updateLine(cm, lastLine, hlText(lastHL) + lastLine.text.slice(to.ch), hlSpans(lastHL));
      for (var i = 1, e = lines.length - 1; i < e; ++i)
        added.push(makeLine(hlText(lines[i]), hlSpans(lines[i]), th));
      if (nlines > 1) doc.remove(from.line + 1, nlines - 1, cm);
      doc.insert(from.line + 1, added);
    }

    if (cm.options.lineWrapping) {
      var perLine = Math.max(5, display.scroller.clientWidth / charWidth(display) - 3);
      doc.iter(from.line, from.line + lines.length, function(line) {
        if (line.height == 0) return;
        var guess = (Math.ceil(line.text.length / perLine) || 1) * th;
        if (guess != line.height) updateLineHeight(line, guess);
      });
    } else {
      doc.iter(checkWidthStart, from.line + lines.length, function(line) {
        var len = lineLength(doc, line);
        if (len > view.maxLineLength) {
          view.maxLine = line;
          view.maxLineLength = len;
          view.maxLineChanged = true;
          recomputeMaxLength = false;
        }
      });
      if (recomputeMaxLength) cm.curOp.updateMaxLine = true;
    }

    // Adjust frontier, schedule worker
    view.frontier = Math.min(view.frontier, from.line);
    startWorker(cm, 400);

    var lendiff = lines.length - nlines - 1;
    // Remember that these lines changed, for updating the display
    regChange(cm, from.line, to.line + 1, lendiff);
    if (hasHandler(cm, "change")) {
      // Normalize lines to contain only strings, since that's what
      // the change event handler expects
      for (var i = 0; i < lines.length; ++i)
        if (typeof lines[i] != "string") lines[i] = lines[i].text;
      var changeObj = {from: from, to: to, text: lines, origin: origin};
      if (cm.curOp.textChanged) {
        for (var cur = cm.curOp.textChanged; cur.next; cur = cur.next) {}
        cur.next = changeObj;
      } else cm.curOp.textChanged = changeObj;
    }

    // Update the selection
    var newSelFrom, newSelTo, end = {line: from.line + lines.length - 1,
                                     ch: hlText(lastHL).length  + (lines.length == 1 ? from.ch : 0)};
    if (selUpdate && typeof selUpdate != "string") {
      if (selUpdate.from) { newSelFrom = selUpdate.from; newSelTo = selUpdate.to; }
      else newSelFrom = newSelTo = selUpdate;
    } else if (selUpdate == "end") {
      newSelFrom = newSelTo = end;
    } else if (selUpdate == "start") {
      newSelFrom = newSelTo = from;
    } else if (selUpdate == "around") {
      newSelFrom = from; newSelTo = end;
    } else {
      var adjustPos = function(pos) {
        if (posLess(pos, from)) return pos;
        if (!posLess(to, pos)) return end;
        var line = pos.line + lendiff;
        var ch = pos.ch;
        if (pos.line == to.line)
          ch += hlText(lastHL).length - (to.ch - (to.line == from.line ? from.ch : 0));
        return {line: line, ch: ch};
      };
      newSelFrom = adjustPos(view.sel.from);
      newSelTo = adjustPos(view.sel.to);
    }
    setSelection(cm, newSelFrom, newSelTo, null, true);
    return end;
  }

  function replaceRange(cm, code, from, to, origin) {
    if (!to) to = from;
    if (posLess(to, from)) { var tmp = to; to = from; from = tmp; }
    return updateDoc(cm, from, to, splitLines(code), null, origin);
  }

  // SELECTION

  function posEq(a, b) {return a.line == b.line && a.ch == b.ch;}
  function posLess(a, b) {return a.line < b.line || (a.line == b.line && a.ch < b.ch);}
  function copyPos(x) {return {line: x.line, ch: x.ch};}

  function clipLine(doc, n) {return Math.max(0, Math.min(n, doc.size-1));}
  function clipPos(doc, pos) {
    if (pos.line < 0) return {line: 0, ch: 0};
    if (pos.line >= doc.size) return {line: doc.size-1, ch: getLine(doc, doc.size-1).text.length};
    var ch = pos.ch, linelen = getLine(doc, pos.line).text.length;
    if (ch == null || ch > linelen) return {line: pos.line, ch: linelen};
    else if (ch < 0) return {line: pos.line, ch: 0};
    else return pos;
  }
  function isLine(doc, l) {return l >= 0 && l < doc.size;}

  // If shift is held, this will move the selection anchor. Otherwise,
  // it'll set the whole selection.
  function extendSelection(cm, pos, other, bias) {
    var sel = cm.view.sel;
    if (sel.shift || sel.extend) {
      var anchor = sel.anchor;
      if (other) {
        var posBefore = posLess(pos, anchor);
        if (posBefore != posLess(other, anchor)) {
          anchor = pos;
          pos = other;
        } else if (posBefore != posLess(pos, other)) {
          pos = other;
        }
      }
      setSelection(cm, anchor, pos, bias);
    } else {
      setSelection(cm, pos, other || pos, bias);
    }
    cm.curOp.userSelChange = true;
  }

  // Update the selection. Last two args are only used by
  // updateDoc, since they have to be expressed in the line
  // numbers before the update.
  function setSelection(cm, anchor, head, bias, checkAtomic) {
    cm.view.goalColumn = null;
    var sel = cm.view.sel;
    // Skip over atomic spans.
    if (checkAtomic || !posEq(anchor, sel.anchor))
      anchor = skipAtomic(cm, anchor, bias, checkAtomic != "push");
    if (checkAtomic || !posEq(head, sel.head))
      head = skipAtomic(cm, head, bias, checkAtomic != "push");

    if (posEq(sel.anchor, anchor) && posEq(sel.head, head)) return;

    sel.anchor = anchor; sel.head = head;
    var inv = posLess(head, anchor);
    sel.from = inv ? head : anchor;
    sel.to = inv ? anchor : head;

    cm.curOp.updateInput = true;
    cm.curOp.selectionChanged = true;
  }

  function reCheckSelection(cm) {
    setSelection(cm, cm.view.sel.from, cm.view.sel.to, null, "push");
  }

  function skipAtomic(cm, pos, bias, mayClear) {
    var doc = cm.view.doc, flipped = false, curPos = pos;
    var dir = bias || 1;
    cm.view.cantEdit = false;
    search: for (;;) {
      var line = getLine(doc, curPos.line), toClear;
      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 <= curPos.ch : sp.from < curPos.ch)) &&
              (sp.to == null || (m.inclusiveRight ? sp.to >= curPos.ch : sp.to > curPos.ch))) {
            if (mayClear && m.clearOnEnter) {
              (toClear || (toClear = [])).push(m);
              continue;
            } else if (!m.atomic) continue;
            var newPos = m.find()[dir < 0 ? "from" : "to"];
            if (posEq(newPos, curPos)) {
              newPos.ch += dir;
              if (newPos.ch < 0) {
                if (newPos.line) newPos = clipPos(doc, {line: newPos.line - 1});
                else newPos = null;
              } else if (newPos.ch > line.text.length) {
                if (newPos.line < doc.size - 1) newPos = {line: newPos.line + 1, ch: 0};
                else newPos = null;
              }
              if (!newPos) {
                if (flipped) {
                  // Driven in a corner -- no valid cursor position found at all
                  // -- try again *with* clearing, if we didn't already
                  if (!mayClear) return skipAtomic(cm, pos, bias, true);
                  // Otherwise, turn off editing until further notice, and return the start of the doc
                  cm.view.cantEdit = true;
                  return {line: 0, ch: 0};
                }
                flipped = true; newPos = pos; dir = -dir;
              }
            }
            curPos = newPos;
            continue search;
          }
        }
        if (toClear) for (var i = 0; i < toClear.length; ++i) toClear[i].clear();
      }
      return curPos;
    }
  }

  // SCROLLING

  function scrollCursorIntoView(cm) {
    var view = cm.view;
    var coords = scrollPosIntoView(cm, view.sel.head);
    if (!view.focused) return;
    var display = cm.display, box = display.sizer.getBoundingClientRect(), doScroll = null;
    if (coords.top + box.top < 0) doScroll = true;
    else if (coords.bottom + box.top > (window.innerHeight || document.documentElement.clientHeight)) doScroll = false;
    if (doScroll != null && !phantom) {
      var hidden = display.cursor.style.display == "none";
      if (hidden) {
        display.cursor.style.display = "";
        display.cursor.style.left = coords.left + "px";
        display.cursor.style.top = (coords.top - display.viewOffset) + "px";
      }
      display.cursor.scrollIntoView(doScroll);
      if (hidden) display.cursor.style.display = "none";
    }
  }

  function scrollPosIntoView(cm, pos) {
    for (;;) {
      var changed = false, coords = cursorCoords(cm, pos);
      var scrollPos = calculateScrollPos(cm, coords.left, coords.top, coords.left, coords.bottom);
      var startTop = cm.view.scrollTop, startLeft = cm.view.scrollLeft;
      if (scrollPos.scrollTop != null) {
        setScrollTop(cm, scrollPos.scrollTop);
        if (Math.abs(cm.view.scrollTop - startTop) > 1) changed = true;
      }
      if (scrollPos.scrollLeft != null) {
        setScrollLeft(cm, scrollPos.scrollLeft);
        if (Math.abs(cm.view.scrollLeft - startLeft) > 1) changed = true;
      }
      if (!changed) return coords;
    }
  }

  function scrollIntoView(cm, x1, y1, x2, y2) {
    var scrollPos = calculateScrollPos(cm, x1, y1, x2, y2);
    if (scrollPos.scrollTop != null) setScrollTop(cm, scrollPos.scrollTop);
    if (scrollPos.scrollLeft != null) setScrollLeft(cm, scrollPos.scrollLeft);
  }

  function calculateScrollPos(cm, x1, y1, x2, y2) {
    var display = cm.display, pt = paddingTop(display);
    y1 += pt; y2 += pt;
    var screen = display.scroller.clientHeight - scrollerCutOff, screentop = display.scroller.scrollTop, result = {};
    var docBottom = cm.view.doc.height + 2 * pt;
    var atTop = y1 < pt + 10, atBottom = y2 + pt > docBottom - 10;
    if (y1 < screentop) result.scrollTop = atTop ? 0 : Math.max(0, y1);
    else if (y2 > screentop + screen) result.scrollTop = (atBottom ? docBottom : y2) - screen;

    var screenw = display.scroller.clientWidth - scrollerCutOff, screenleft = display.scroller.scrollLeft;
    x1 += display.gutters.offsetWidth; x2 += display.gutters.offsetWidth;
    var gutterw = display.gutters.offsetWidth;
    var atLeft = x1 < gutterw + 10;
    if (x1 < screenleft + gutterw || atLeft) {
      if (atLeft) x1 = 0;
      result.scrollLeft = Math.max(0, x1 - 10 - gutterw);
    } else if (x2 > screenw + screenleft - 3) {
      result.scrollLeft = x2 + 10 - screenw;
    }
    return result;
  }

  // API UTILITIES

  function indentLine(cm, n, how, aggressive) {
    var doc = cm.view.doc;
    if (!how) how = "add";
    if (how == "smart") {
      if (!cm.view.mode.indent) how = "prev";
      else var state = getStateBefore(cm, n);
    }

    var tabSize = cm.options.tabSize;
    var line = getLine(doc, n), curSpace = countColumn(line.text, null, tabSize);
    var curSpaceString = line.text.match(/^\s*/)[0], indentation;
    if (how == "smart") {
      indentation = cm.view.mode.indent(state, line.text.slice(curSpaceString.length), line.text);
      if (indentation == Pass) {
        if (!aggressive) return;
        how = "prev";
      }
    }
    if (how == "prev") {
      if (n) 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;
    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(cm, indentString, {line: n, ch: 0}, {line: n, ch: curSpaceString.length}, "input");
    line.stateAfter = null;
  }

  function changeLine(cm, handle, op) {
    var no = handle, line = handle, doc = cm.view.doc;
    if (typeof handle == "number") line = getLine(doc, clipLine(doc, handle));
    else no = lineNo(handle);
    if (no == null) return null;
    if (op(line, no)) regChange(cm, no, no + 1);
    else return null;
    return line;
  }

  function findPosH(cm, dir, unit, visually) {
    var doc = cm.view.doc, end = cm.view.sel.head, line = end.line, ch = end.ch;
    var lineObj = getLine(doc, line);
    function findNextLine() {
      var l = line + dir;
      if (l < 0 || l == doc.size) return false;
      line = l;
      return lineObj = getLine(doc, l);
    }
    function moveOnce(boundToLine) {
      var next = (visually ? moveVisually : moveLogically)(lineObj, ch, dir, true);
      if (next == null) {
        if (!boundToLine && findNextLine()) {
          if (visually) ch = (dir < 0 ? lineRight : lineLeft)(lineObj);
          else ch = dir < 0 ? lineObj.text.length : 0;
        } else return false;
      } else ch = next;
      return true;
    }
    if (unit == "char") moveOnce();
    else if (unit == "column") moveOnce(true);
    else if (unit == "word") {
      var sawWord = false;
      for (;;) {
        if (dir < 0) if (!moveOnce()) break;
        if (isWordChar(lineObj.text.charAt(ch))) sawWord = true;
        else if (sawWord) {if (dir < 0) {dir = 1; moveOnce();} break;}
        if (dir > 0) if (!moveOnce()) break;
      }
    }
    return skipAtomic(cm, {line: line, ch: ch}, dir, true);
  }

  function findWordAt(line, pos) {
    var start = pos.ch, end = pos.ch;
    if (line) {
      if (pos.after === false || end == line.length) --start; else ++end;
      var startChar = line.charAt(start);
      var check = isWordChar(startChar) ? isWordChar :
        /\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 {from: {line: pos.line, ch: start}, to: {line: pos.line, ch: end}};
  }

  function selectLine(cm, line) {
    extendSelection(cm, {line: line, ch: 0}, clipPos(cm.view.doc, {line: line + 1, ch: 0}));
  }

  // PROTOTYPE

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

  CodeMirror.prototype = {
    getValue: function(lineSep) {
      var text = [], doc = this.view.doc;
      doc.iter(0, doc.size, function(line) { text.push(line.text); });
      return text.join(lineSep || "\n");
    },

    setValue: operation(null, function(code) {
      var doc = this.view.doc, top = {line: 0, ch: 0}, lastLen = getLine(doc, doc.size-1).text.length;
      updateDocInner(this, top, {line: doc.size - 1, ch: lastLen}, splitLines(code), top, top, "setValue");
    }),

    getSelection: function(lineSep) { return this.getRange(this.view.sel.from, this.view.sel.to, lineSep); },

    replaceSelection: operation(null, function(code, collapse, origin) {
      var sel = this.view.sel;
      updateDoc(this, sel.from, sel.to, splitLines(code), collapse || "around", origin);
    }),

    focus: function(){window.focus(); focusInput(this); onFocus(this); fastPoll(this);},

    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);
    },

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

    getMode: function() {return this.view.mode;},

    addKeyMap: function(map) {
      this.view.keyMaps.push(map);
    },

    removeKeyMap: function(map) {
      var maps = this.view.keyMaps;
      for (var i = 0; i < maps.length; ++i)
        if ((typeof map == "string" ? maps[i].name : maps[i]) == map) {
          maps.splice(i, 1);
          return true;
        }
    },

    undo: operation(null, function() {unredoHelper(this, "undo");}),
    redo: operation(null, function() {unredoHelper(this, "redo");}),

    indentLine: operation(null, function(n, dir, aggressive) {
      if (typeof dir != "string") {
        if (dir == null) dir = this.options.smartIndent ? "smart" : "prev";
        else dir = dir ? "add" : "subtract";
      }
      if (isLine(this.view.doc, n)) indentLine(this, n, dir, aggressive);
    }),

    indentSelection: operation(null, function(how) {
      var sel = this.view.sel;
      if (posEq(sel.from, sel.to)) return indentLine(this, sel.from.line, how);
      var e = sel.to.line - (sel.to.ch ? 0 : 1);
      for (var i = sel.from.line; i <= e; ++i) indentLine(this, i, how);
    }),

    historySize: function() {
      var hist = this.view.history;
      return {undo: hist.done.length, redo: hist.undone.length};
    },

    clearHistory: function() {this.view.history = makeHistory();},

    markClean: function() {
      this.view.history.dirtyCounter = 0;
      this.view.history.lastOp = this.view.history.lastOrigin = null;
    },

    isClean: function () {return this.view.history.dirtyCounter == 0;},
      
    getHistory: function() {
      var hist = this.view.history;
      function cp(arr) {
        for (var i = 0, nw = [], nwelt; i < arr.length; ++i) {
          var set = arr[i];
          nw.push({events: nwelt = [], fromBefore: set.fromBefore, toBefore: set.toBefore,
                   fromAfter: set.fromAfter, toAfter: set.toAfter});
          for (var j = 0, elt = set.events; j < elt.length; ++j) {
            var old = [], cur = elt[j];
            nwelt.push({start: cur.start, added: cur.added, old: old});
            for (var k = 0; k < cur.old.length; ++k) old.push(hlText(cur.old[k]));
          }
        }
        return nw;
      }
      return {done: cp(hist.done), undone: cp(hist.undone)};
    },

    setHistory: function(histData) {
      var hist = this.view.history = makeHistory();
      hist.done = histData.done;
      hist.undone = histData.undone;
    },

    // Fetch the parser token for a given character. Useful for hacks
    // that want to inspect the mode state (say, for completion).
    getTokenAt: function(pos) {
      var doc = this.view.doc;
      pos = clipPos(doc, pos);
      var state = getStateBefore(this, pos.line), mode = this.view.mode;
      var line = getLine(doc, pos.line);
      var stream = new StringStream(line.text, this.options.tabSize);
      while (stream.pos < pos.ch && !stream.eol()) {
        stream.start = stream.pos;
        var style = mode.token(stream, state);
      }
      return {start: stream.start,
              end: stream.pos,
              string: stream.current(),
              className: style || null, // Deprecated, use 'type' instead
              type: style || null,
              state: state};
    },

    getStateAfter: function(line) {
      var doc = this.view.doc;
      line = clipLine(doc, line == null ? doc.size - 1: line);
      return getStateBefore(this, line + 1);
    },

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

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

    coordsChar: function(coords) {
      var off = this.display.lineSpace.getBoundingClientRect();
      return coordsChar(this, coords.left - off.left, coords.top - off.top);
    },

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

    markText: operation(null, function(from, to, options) {
      return markText(this, clipPos(this.view.doc, from), clipPos(this.view.doc, to),
                      options, "range");
    }),

    setBookmark: operation(null, function(pos, widget) {
      pos = clipPos(this.view.doc, pos);
      return markText(this, pos, pos, widget ? {replacedWith: widget} : {}, "bookmark");
    }),

    findMarksAt: function(pos) {
      var doc = this.view.doc;
      pos = clipPos(doc, pos);
      var markers = [], spans = getLine(doc, 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);
      }
      return markers;
    },

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

    clearGutter: operation(null, function(gutterID) {
      var i = 0, cm = this, doc = cm.view.doc;
      doc.iter(0, doc.size, function(line) {
        if (line.gutterMarkers && line.gutterMarkers[gutterID]) {
          line.gutterMarkers[gutterID] = null;
          regChange(cm, i, i + 1);
          if (isEmpty(line.gutterMarkers)) line.gutterMarkers = null;
        }
        ++i;
      });
    }),

    addLineClass: operation(null, function(handle, where, cls) {
      return changeLine(this, handle, function(line) {
        var prop = where == "text" ? "textClass" : where == "background" ? "bgClass" : "wrapClass";
        if (!line[prop]) line[prop] = cls;
        else if (new RegExp("\\b" + cls + "\\b").test(line[prop])) return false;
        else line[prop] += " " + cls;
        return true;
      });
    }),

    removeLineClass: operation(null, function(handle, where, cls) {
      return changeLine(this, handle, function(line) {
        var prop = where == "text" ? "textClass" : where == "background" ? "bgClass" : "wrapClass";
        var cur = line[prop];
        if (!cur) return false;
        else if (cls == null) line[prop] = null;
        else {
          var upd = cur.replace(new RegExp("^" + cls + "\\b\\s*|\\s*\\b" + cls + "\\b"), "");
          if (upd == cur) return false;
          line[prop] = upd || null;
        }
        return true;
      });
    }),

    addLineWidget: operation(null, function(handle, node, options) {
      var widget = options || {};
      widget.node = node;
      if (widget.noHScroll) this.display.alignWidgets = true;
      changeLine(this, handle, function(line) {
        (line.widgets || (line.widgets = [])).push(widget);
        widget.line = line;
        return true;
      });
      return widget;
    }),

    removeLineWidget: operation(null, function(widget) {
      var ws = widget.line.widgets, no = lineNo(widget.line);
      if (no == null) return;
      for (var i = 0; i < ws.length; ++i) if (ws[i] == widget) ws.splice(i--, 1);
      regChange(this, no, no + 1);
    }),

    lineInfo: function(line) {
      if (typeof line == "number") {
        if (!isLine(this.view.doc, line)) return null;
        var n = line;
        line = getLine(this.view.doc, line);
        if (!line) return null;
      } else {
        var 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};
    },

    getViewport: function() { return {from: this.display.showingFrom, to: this.display.showingTo};},

    addWidget: function(pos, node, scroll, vert, horiz) {
      var display = this.display;
      pos = cursorCoords(this, clipPos(this.view.doc, pos));
      var top = pos.top, left = pos.left;
      node.style.position = "absolute";
      display.sizer.appendChild(node);
      if (vert == "over") top = pos.top;
      else if (vert == "near") {
        var vspace = Math.max(display.wrapper.clientHeight, this.view.doc.height),
        hspace = Math.max(display.sizer.clientWidth, display.lineSpace.clientWidth);
        if (pos.bottom + node.offsetHeight > vspace && pos.top > node.offsetHeight)
          top = pos.top - node.offsetHeight;
        if (left + node.offsetWidth > hspace)
          left = hspace - node.offsetWidth;
      }
      node.style.top = (top + paddingTop(display)) + "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, top, left + node.offsetWidth, top + node.offsetHeight);
    },

    lineCount: function() {return this.view.doc.size;},

    clipPos: function(pos) {return clipPos(this.view.doc, pos);},

    getCursor: function(start) {
      var sel = this.view.sel, pos;
      if (start == null || start == "head") pos = sel.head;
      else if (start == "anchor") pos = sel.anchor;
      else if (start == "end" || start === false) pos = sel.to;
      else pos = sel.from;
      return copyPos(pos);
    },

    somethingSelected: function() {return !posEq(this.view.sel.from, this.view.sel.to);},

    setCursor: operation(null, function(line, ch, extend) {
      var pos = clipPos(this.view.doc, typeof line == "number" ? {line: line, ch: ch || 0} : line);
      if (extend) extendSelection(this, pos);
      else setSelection(this, pos, pos);
    }),

    setSelection: operation(null, function(anchor, head) {
      var doc = this.view.doc;
      setSelection(this, clipPos(doc, anchor), clipPos(doc, head || anchor));
    }),

    extendSelection: operation(null, function(from, to) {
      var doc = this.view.doc;
      extendSelection(this, clipPos(doc, from), to && clipPos(doc, to));
    }),

    setExtending: function(val) {this.view.sel.extend = val;},

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

    getLineHandle: function(line) {
      var doc = this.view.doc;
      if (isLine(doc, line)) return getLine(doc, line);
    },

    getLineNumber: function(line) {return lineNo(line);},

    setLine: operation(null, function(line, text) {
      if (isLine(this.view.doc, line))
        replaceRange(this, text, {line: line, ch: 0}, {line: line, ch: getLine(this.view.doc, line).text.length});
    }),

    removeLine: operation(null, function(line) {
      if (isLine(this.view.doc, line))
        replaceRange(this, "", {line: line, ch: 0}, clipPos(this.view.doc, {line: line+1, ch: 0}));
    }),

    replaceRange: operation(null, function(code, from, to) {
      var doc = this.view.doc;
      from = clipPos(doc, from);
      to = to ? clipPos(doc, to) : from;
      return replaceRange(this, code, from, to);
    }),

    getRange: function(from, to, lineSep) {
      var doc = this.view.doc;
      from = clipPos(doc, from); to = clipPos(doc, to);
      var l1 = from.line, l2 = to.line;
      if (l1 == l2) return getLine(doc, l1).text.slice(from.ch, to.ch);
      var code = [getLine(doc, l1).text.slice(from.ch)];
      doc.iter(l1 + 1, l2, function(line) { code.push(line.text); });
      code.push(getLine(doc, l2).text.slice(0, to.ch));
      return code.join(lineSep || "\n");
    },

    triggerOnKeyDown: operation(null, onKeyDown),

    execCommand: function(cmd) {return commands[cmd](this);},

    // Stuff used by commands, probably not much use to outside code.
    moveH: operation(null, function(dir, unit) {
      var sel = this.view.sel, pos = dir < 0 ? sel.from : sel.to;
      if (sel.shift || sel.extend || posEq(sel.from, sel.to)) pos = findPosH(this, dir, unit, true);
      extendSelection(this, pos, pos, dir);
    }),

    deleteH: operation(null, function(dir, unit) {
      var sel = this.view.sel;
      if (!posEq(sel.from, sel.to)) replaceRange(this, "", sel.from, sel.to, "delete");
      else replaceRange(this, "", sel.from, findPosH(this, dir, unit, false), "delete");
      this.curOp.userSelChange = true;
    }),

    moveV: operation(null, function(dir, unit) {
      var view = this.view, doc = view.doc, display = this.display;
      var cur = view.sel.head, pos = cursorCoords(this, cur, "div");
      var x = pos.left, y;
      if (view.goalColumn != null) x = view.goalColumn;
      if (unit == "page") {
        var pageSize = Math.min(display.wrapper.clientHeight, window.innerHeight || document.documentElement.clientHeight);
        y = pos.top + dir * pageSize;
      } else if (unit == "line") {
        y = dir > 0 ? pos.bottom + 3 : pos.top - 3;
      }
      do {
        var target = coordsChar(this, x, y);
        y += dir * 5;
      } while (target.outside && (dir < 0 ? y > 0 : y < doc.height));

      if (unit == "page") display.scrollbarV.scrollTop += charCoords(this, target, "div").top - pos.top;
      extendSelection(this, target, target, dir);
      view.goalColumn = x;
    }),

    toggleOverwrite: function() {
      if (this.view.overwrite = !this.view.overwrite)
        this.display.cursor.className += " CodeMirror-overwrite";
      else
        this.display.cursor.className = this.display.cursor.className.replace(" CodeMirror-overwrite", "");
    },

    posFromIndex: function(off) {
      var lineNo = 0, ch, doc = this.view.doc;
      doc.iter(0, doc.size, function(line) {
        var sz = line.text.length + 1;
        if (sz > off) { ch = off; return true; }
        off -= sz;
        ++lineNo;
      });
      return clipPos(doc, {line: lineNo, ch: ch});
    },
    indexFromPos: function (coords) {
      if (coords.line < 0 || coords.ch < 0) return 0;
      var index = coords.ch;
      this.view.doc.iter(0, coords.line, function (line) {
        index += line.text.length + 1;
      });
      return index;
    },

    scrollTo: function(x, y) {
      if (x != null) this.display.scrollbarH.scrollLeft = this.display.scroller.scrollLeft = x;
      if (y != null) this.display.scrollbarV.scrollTop = this.display.scroller.scrollTop = y;
      updateDisplay(this, []);
    },
    getScrollInfo: function() {
      var scroller = this.display.scroller, co = scrollerCutOff;
      return {left: scroller.scrollLeft, top: scroller.scrollTop,
              height: scroller.scrollHeight - co, width: scroller.scrollWidth - co,
              clientHeight: scroller.clientHeight - co, clientWidth: scroller.clientWidth - co};
    },

    scrollIntoView: function(pos) {
      if (typeof pos == "number") pos = {line: pos, ch: 0};
      pos = pos ? clipPos(this.view.doc, pos) : this.view.sel.head;
      scrollPosIntoView(this, pos);
    },

    setSize: function(width, height) {
      function interpret(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);
      this.refresh();
    },

    on: function(type, f) {on(this, type, f);},
    off: function(type, f) {off(this, type, f);},

    operation: function(f){return operation(this, f)();},

    refresh: function() {
      clearCaches(this);
      if (this.display.scroller.scrollHeight > this.view.scrollTop)
        this.display.scrollbarV.scrollTop = this.display.scroller.scrollTop = this.view.scrollTop;
      updateDisplay(this, true);
    },

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

  // OPTION DEFAULTS

  var optionHandlers = CodeMirror.optionHandlers = {};

  // The default configuration options.
  var defaults = CodeMirror.defaults = {};

  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;
  }

  var Init = CodeMirror.Init = {toString: function(){return "CodeMirror.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) {cm.setValue(val);}, true);
  option("mode", null, loadMode, true);

  option("indentUnit", 2, loadMode, true);
  option("indentWithTabs", false);
  option("smartIndent", true);
  option("tabSize", 4, function(cm) {
    loadMode(cm);
    clearCaches(cm);
    updateDisplay(cm, true);
  }, true);
  option("electricChars", true);

  option("theme", "default", function(cm) {
    themeChanged(cm);
    guttersChanged(cm);
  }, true);
  option("keyMap", "default", keyMapChanged);
  option("extraKeys", null);

  option("onKeyEvent", null);
  option("onDragEvent", null);

  option("lineWrapping", false, wrappingChanged, true);
  option("gutters", [], function(cm) {
    setGuttersForLineNumbers(cm.options);
    guttersChanged(cm);
  }, 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("readOnly", false, function(cm, val) {
    if (val == "nocursor") {onBlur(cm); cm.display.input.blur();}
    else if (!val) resetInput(cm, true);
  });
  option("dragDrop", true);

  option("cursorBlinkRate", 530);
  option("cursorHeight", 1);
  option("workTime", 100);
  option("workDelay", 100);
  option("flattenSpans", true);
  option("pollInterval", 100);
  option("undoDepth", 40);
  option("viewportMargin", 10, function(cm){cm.refresh();}, true);

  option("tabindex", null, function(cm, val) {
    cm.display.input.tabIndex = val || "";
  });
  option("autofocus", null);

  // MODE DEFINITION AND QUERYING

  // Known modes, by name and by MIME
  var modes = CodeMirror.modes = {}, mimeModes = CodeMirror.mimeModes = {};

  CodeMirror.defineMode = function(name, mode) {
    if (!CodeMirror.defaults.mode && name != "null") CodeMirror.defaults.mode = name;
    if (arguments.length > 2) {
      mode.dependencies = [];
      for (var i = 2; i < arguments.length; ++i) mode.dependencies.push(arguments[i]);
    }
    modes[name] = mode;
  };

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

  CodeMirror.resolveMode = function(spec) {
    if (typeof spec == "string" && mimeModes.hasOwnProperty(spec))
      spec = mimeModes[spec];
    else if (typeof spec == "string" && /^[\w\-]+\/[\w\-]+\+xml$/.test(spec))
      return CodeMirror.resolveMode("application/xml");
    if (typeof spec == "string") return {name: spec};
    else return spec || {name: "null"};
  };

  CodeMirror.getMode = function(options, spec) {
    var spec = CodeMirror.resolveMode(spec);
    var mfactory = modes[spec.name];
    if (!mfactory) return CodeMirror.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;
    return modeObj;
  };

  CodeMirror.defineMode("null", function() {
    return {token: function(stream) {stream.skipToEnd();}};
  });
  CodeMirror.defineMIME("text/plain", "null");

  var modeExtensions = CodeMirror.modeExtensions = {};
  CodeMirror.extendMode = function(mode, properties) {
    var exts = modeExtensions.hasOwnProperty(mode) ? modeExtensions[mode] : (modeExtensions[mode] = {});
    for (var prop in properties) if (properties.hasOwnProperty(prop))
      exts[prop] = properties[prop];
  };

  // EXTENSIONS

  CodeMirror.defineExtension = function(name, func) {
    CodeMirror.prototype[name] = func;
  };

  CodeMirror.defineOption = option;

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

  // MODE STATE HANDLING

  // Utility functions for working with state. Exported because modes
  // sometimes need to do this.
  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;
  }
  CodeMirror.copyState = copyState;

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

  CodeMirror.innerMode = function(mode, state) {
    while (mode.innerMode) {
      var info = mode.innerMode(state);
      state = info.state;
      mode = info.mode;
    }
    return info || {mode: mode, state: state};
  };

  // STANDARD COMMANDS

  var commands = CodeMirror.commands = {
    selectAll: function(cm) {cm.setSelection({line: 0, ch: 0}, {line: cm.lineCount() - 1});},
    killLine: function(cm) {
      var from = cm.getCursor(true), to = cm.getCursor(false), sel = !posEq(from, to);
      if (!sel && cm.getLine(from.line).length == from.ch)
        cm.replaceRange("", from, {line: from.line + 1, ch: 0}, "delete");
      else cm.replaceRange("", from, sel ? to : {line: from.line}, "delete");
    },
    deleteLine: function(cm) {
      var l = cm.getCursor().line;
      cm.replaceRange("", {line: l, ch: 0}, {line: l}, "delete");
    },
    undo: function(cm) {cm.undo();},
    redo: function(cm) {cm.redo();},
    goDocStart: function(cm) {cm.extendSelection({line: 0, ch: 0});},
    goDocEnd: function(cm) {cm.extendSelection({line: cm.lineCount() - 1});},
    goLineStart: function(cm) {
      cm.extendSelection(lineStart(cm, cm.getCursor().line));
    },
    goLineStartSmart: function(cm) {
      var cur = cm.getCursor(), start = lineStart(cm, cur.line);
      var line = cm.getLineHandle(start.line);
      var order = getOrder(line);
      if (!order || order[0].level == 0) {
        var firstNonWS = Math.max(0, line.text.search(/\S/));
        var inWS = cur.line == start.line && cur.ch <= firstNonWS && cur.ch;
        cm.extendSelection({line: start.line, ch: inWS ? 0 : firstNonWS});
      } else cm.extendSelection(start);
    },
    goLineEnd: function(cm) {
      cm.extendSelection(lineEnd(cm, cm.getCursor().line));
    },
    goLineUp: function(cm) {cm.moveV(-1, "line");},
    goLineDown: function(cm) {cm.moveV(1, "line");},
    goPageUp: function(cm) {cm.moveV(-1, "page");},
    goPageDown: function(cm) {cm.moveV(1, "page");},
    goCharLeft: function(cm) {cm.moveH(-1, "char");},
    goCharRight: function(cm) {cm.moveH(1, "char");},
    goColumnLeft: function(cm) {cm.moveH(-1, "column");},
    goColumnRight: function(cm) {cm.moveH(1, "column");},
    goWordLeft: function(cm) {cm.moveH(-1, "word");},
    goWordRight: function(cm) {cm.moveH(1, "word");},
    delCharBefore: function(cm) {cm.deleteH(-1, "char");},
    delCharAfter: function(cm) {cm.deleteH(1, "char");},
    delWordBefore: function(cm) {cm.deleteH(-1, "word");},
    delWordAfter: function(cm) {cm.deleteH(1, "word");},
    indentAuto: function(cm) {cm.indentSelection("smart");},
    indentMore: function(cm) {cm.indentSelection("add");},
    indentLess: function(cm) {cm.indentSelection("subtract");},
    insertTab: function(cm) {cm.replaceSelection("\t", "end", "input");},
    defaultTab: function(cm) {
      if (cm.somethingSelected()) cm.indentSelection("add");
      else cm.replaceSelection("\t", "end", "input");
    },
    transposeChars: function(cm) {
      var cur = cm.getCursor(), line = cm.getLine(cur.line);
      if (cur.ch > 0 && cur.ch < line.length - 1)
        cm.replaceRange(line.charAt(cur.ch) + line.charAt(cur.ch - 1),
                        {line: cur.line, ch: cur.ch - 1}, {line: cur.line, ch: cur.ch + 1});
    },
    newlineAndIndent: function(cm) {
      operation(cm, function() {
        cm.replaceSelection("\n", "end", "input");
        cm.indentLine(cm.getCursor().line, null, true);
      })();
    },
    toggleOverwrite: function(cm) {cm.toggleOverwrite();}
  };

  // STANDARD KEYMAPS

  var keyMap = CodeMirror.keyMap = {};
  keyMap.basic = {
    "Left": "goCharLeft", "Right": "goCharRight", "Up": "goLineUp", "Down": "goLineDown",
    "End": "goLineEnd", "Home": "goLineStartSmart", "PageUp": "goPageUp", "PageDown": "goPageDown",
    "Delete": "delCharAfter", "Backspace": "delCharBefore", "Tab": "defaultTab", "Shift-Tab": "indentAuto",
    "Enter": "newlineAndIndent", "Insert": "toggleOverwrite"
  };
  // Note that the save and find-related commands aren't defined by
  // default. 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", "Alt-Up": "goDocStart", "Ctrl-End": "goDocEnd", "Ctrl-Down": "goDocEnd",
    "Ctrl-Left": "goWordLeft", "Ctrl-Right": "goWordRight", "Alt-Left": "goLineStart", "Alt-Right": "goLineEnd",
    "Ctrl-Backspace": "delWordBefore", "Ctrl-Delete": "delWordAfter", "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",
    fallthrough: "basic"
  };
  keyMap.macDefault = {
    "Cmd-A": "selectAll", "Cmd-D": "deleteLine", "Cmd-Z": "undo", "Shift-Cmd-Z": "redo", "Cmd-Y": "redo",
    "Cmd-Up": "goDocStart", "Cmd-End": "goDocEnd", "Cmd-Down": "goDocEnd", "Alt-Left": "goWordLeft",
    "Alt-Right": "goWordRight", "Cmd-Left": "goLineStart", "Cmd-Right": "goLineEnd", "Alt-Backspace": "delWordBefore",
    "Ctrl-Alt-Backspace": "delWordAfter", "Alt-Delete": "delWordAfter", "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",
    fallthrough: ["basic", "emacsy"]
  };
  keyMap["default"] = mac ? keyMap.macDefault : keyMap.pcDefault;
  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"
  };

  // KEYMAP DISPATCH

  function getKeyMap(val) {
    if (typeof val == "string") return keyMap[val];
    else return val;
  }

  function lookupKey(name, maps, handle, stop) {
    function lookup(map) {
      map = getKeyMap(map);
      var found = map[name];
      if (found === false) {
        if (stop) stop();
        return true;
      }
      if (found != null && handle(found)) return true;
      if (map.nofallthrough) {
        if (stop) stop();
        return true;
      }
      var fallthrough = map.fallthrough;
      if (fallthrough == null) return false;
      if (Object.prototype.toString.call(fallthrough) != "[object Array]")
        return lookup(fallthrough);
      for (var i = 0, e = fallthrough.length; i < e; ++i) {
        if (lookup(fallthrough[i])) return true;
      }
      return false;
    }

    for (var i = 0; i < maps.length; ++i)
      if (lookup(maps[i])) return true;
  }
  function isModifierKey(event) {
    var name = keyNames[e_prop(event, "keyCode")];
    return name == "Ctrl" || name == "Alt" || name == "Shift" || name == "Mod";
  }
  CodeMirror.isModifierKey = isModifierKey;

  // FROMTEXTAREA

  CodeMirror.fromTextArea = function(textarea, options) {
    if (!options) options = {};
    options.value = textarea.value;
    if (!options.tabindex && textarea.tabindex)
      options.tabindex = textarea.tabindex;
    // 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 = document.body;
      // doc.activeElement occasionally throws on IE
      try { hasFocus = document.activeElement; } catch(e) {}
      options.autofocus = hasFocus == textarea ||
        textarea.getAttribute("autofocus") != null && hasFocus == document.body;
    }

    function save() {textarea.value = cm.getValue();}
    if (textarea.form) {
      // Deplorable hack to make the submit method do the right thing.
      on(textarea.form, "submit", save);
      var form = textarea.form, realSubmit = form.submit;
      try {
        form.submit = function wrappedSubmit() {
          save();
          form.submit = realSubmit;
          form.submit();
          form.submit = wrappedSubmit;
        };
      } catch(e) {}
    }

    textarea.style.display = "none";
    var cm = CodeMirror(function(node) {
      textarea.parentNode.insertBefore(node, textarea.nextSibling);
    }, options);
    cm.save = save;
    cm.getTextArea = function() { return textarea; };
    cm.toTextArea = function() {
      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;
      }
    };
    return cm;
  };

  // STRING STREAM

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

  // The character stream used by a mode's parser.
  function StringStream(string, tabSize) {
    this.pos = this.start = 0;
    this.string = string;
    this.tabSize = tabSize || 8;
  }

  StringStream.prototype = {
    eol: function() {return this.pos >= this.string.length;},
    sol: function() {return this.pos == 0;},
    peek: function() {return this.string.charAt(this.pos) || undefined;},
    next: function() {
      if (this.pos < this.string.length)
        return this.string.charAt(this.pos++);
    },
    eat: function(match) {
      var ch = this.string.charAt(this.pos);
      if (typeof match == "string") var ok = ch == match;
      else var ok = ch && (match.test ? match.test(ch) : match(ch));
      if (ok) {++this.pos; return ch;}
    },
    eatWhile: function(match) {
      var start = this.pos;
      while (this.eat(match)){}
      return this.pos > start;
    },
    eatSpace: function() {
      var start = this.pos;
      while (/[\s\u00a0]/.test(this.string.charAt(this.pos))) ++this.pos;
      return this.pos > start;
    },
    skipToEnd: function() {this.pos = this.string.length;},
    skipTo: function(ch) {
      var found = this.string.indexOf(ch, this.pos);
      if (found > -1) {this.pos = found; return true;}
    },
    backUp: function(n) {this.pos -= n;},
    column: function() {return countColumn(this.string, this.start, this.tabSize);},
    indentation: function() {return countColumn(this.string, null, this.tabSize);},
    match: function(pattern, consume, caseInsensitive) {
      if (typeof pattern == "string") {
        var cased = function(str) {return caseInsensitive ? str.toLowerCase() : str;};
        if (cased(this.string).indexOf(cased(pattern), this.pos) == this.pos) {
          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;
      }
    },
    current: function(){return this.string.slice(this.start, this.pos);}
  };
  CodeMirror.StringStream = StringStream;

  // TEXTMARKERS

  function TextMarker(cm, type) {
    this.lines = [];
    this.type = type;
    this.cm = cm;
  }

  TextMarker.prototype.clear = function() {
    if (this.explicitlyCleared) return;
    startOperation(this.cm);
    var min = null, max = null;
    for (var i = 0; i < this.lines.length; ++i) {
      var line = this.lines[i];
      var span = getMarkedSpanFor(line.markedSpans, this);
      if (span.to != null) max = lineNo(line);
      line.markedSpans = removeMarkedSpan(line.markedSpans, span);
      if (span.from != null)
        min = lineNo(line);
      else if (this.collapsed && !lineIsHidden(line))
        updateLineHeight(line, textHeight(this.cm.display));
    }
    if (min != null) regChange(this.cm, min, max + 1);
    this.lines.length = 0;
    this.explicitlyCleared = true;
    if (this.collapsed && this.cm.view.cantEdit) {
      this.cm.view.cantEdit = false;
      reCheckSelection(this.cm);
    }
    endOperation(this.cm);
    signalLater(this.cm, this, "clear");
  };

  TextMarker.prototype.find = function() {
    var from, to;
    for (var i = 0; i < this.lines.length; ++i) {
      var line = this.lines[i];
      var span = getMarkedSpanFor(line.markedSpans, this);
      if (span.from != null || span.to != null) {
        var found = lineNo(line);
        if (span.from != null) from = {line: found, ch: span.from};
        if (span.to != null) to = {line: found, ch: span.to};
      }
    }
    if (this.type == "bookmark") return from;
    return from && {from: from, to: to};
  };

  function markText(cm, from, to, options, type) {
    var doc = cm.view.doc;
    var marker = new TextMarker(cm, type);
    if (type == "range" && !posLess(from, to)) return marker;
    if (options) for (var opt in options) if (options.hasOwnProperty(opt))
      marker[opt] = options[opt];
    if (marker.replacedWith) {
      marker.collapsed = true;
      marker.replacedWith = elt("span", [marker.replacedWith], "CodeMirror-widget");
    }
    if (marker.collapsed) sawCollapsedSpans = true;

    var curLine = from.line, size = 0, collapsedAtStart, collapsedAtEnd;
    doc.iter(curLine, to.line + 1, function(line) {
      var span = {from: null, to: null, marker: marker};
      size += line.text.length;
      if (curLine == from.line) {span.from = from.ch; size -= from.ch;}
      if (curLine == to.line) {span.to = to.ch; size -= line.text.length - to.ch;}
      if (marker.collapsed) {
        if (curLine == to.line) collapsedAtEnd = collapsedSpanAt(line, to.ch);
        if (curLine == from.line) collapsedAtStart = collapsedSpanAt(line, from.ch);
        else updateLineHeight(line, 0);
      }
      addMarkedSpan(line, span);
      if (marker.collapsed && curLine == from.line && lineIsHidden(line))
        updateLineHeight(line, 0);
      ++curLine;
    });

    if (marker.readOnly) {
      sawReadOnlySpans = true;
      if (cm.view.history.done.length || cm.view.history.undone.length)
        cm.clearHistory();
    }
    if (marker.collapsed) {
      if (collapsedAtStart != collapsedAtEnd)
        throw new Error("Inserting collapsed marker overlapping an existing one");
      marker.size = size;
      marker.atomic = true;
    }
    if (marker.className || marker.startStyle || marker.endStyle || marker.collapsed)
      regChange(cm, from.line, to.line + 1);
    if (marker.atomic) reCheckSelection(cm);
    return marker;
  }

  // TEXTMARKER SPANS

  function getMarkedSpanFor(spans, marker) {
    if (spans) for (var i = 0; i < spans.length; ++i) {
      var span = spans[i];
      if (span.marker == marker) return span;
    }
  }
  function removeMarkedSpan(spans, span) {
    for (var r, i = 0; i < spans.length; ++i)
      if (spans[i] != span) (r || (r = [])).push(spans[i]);
    return r;
  }
  function addMarkedSpan(line, span) {
    line.markedSpans = line.markedSpans ? line.markedSpans.concat([span]) : [span];
    span.marker.lines.push(line);
  }

  function markedSpansBefore(old, startCh) {
    if (old) for (var i = 0, nw; 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 || marker.type == "bookmark" && span.from == startCh) {
        var endsAfter = span.to == null || (marker.inclusiveRight ? span.to >= startCh : span.to > startCh);
        (nw || (nw = [])).push({from: span.from,
                                to: endsAfter ? null : span.to,
                                marker: marker});
      }
    }
    return nw;
  }

  function markedSpansAfter(old, startCh, endCh) {
    if (old) for (var i = 0, nw; 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 || marker.type == "bookmark" && span.from == endCh && span.from != startCh) {
        var startsBefore = span.from == null || (marker.inclusiveLeft ? span.from <= endCh : span.from < endCh);
        (nw || (nw = [])).push({from: startsBefore ? null : span.from - endCh,
                                to: span.to == null ? null : span.to - endCh,
                                marker: marker});
      }
    }
    return nw;
  }

  function updateMarkedSpans(oldFirst, oldLast, startCh, endCh, newText) {
    if (!oldFirst && !oldLast) return newText;
    // Get the spans that 'stick out' on both sides
    var first = markedSpansBefore(oldFirst, startCh);
    var last = markedSpansAfter(oldLast, startCh, endCh);

    // Next, merge those two ends
    var sameLine = newText.length == 1, offset = lst(newText).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 = 0; i < last.length; ++i) {
        var span = last[i];
        if (span.to != null) span.to += offset;
        if (span.from == null) {
          var found = getMarkedSpanFor(first, span.marker);
          if (!found) {
            span.from = offset;
            if (sameLine) (first || (first = [])).push(span);
          }
        } else {
          span.from += offset;
          if (sameLine) (first || (first = [])).push(span);
        }
      }
    }

    var newMarkers = [newHL(newText[0], first)];
    if (!sameLine) {
      // Fill gap with whole-line-spans
      var gap = newText.length - 2, gapMarkers;
      if (gap > 0 && first)
        for (var i = 0; i < first.length; ++i)
          if (first[i].to == null)
            (gapMarkers || (gapMarkers = [])).push({from: null, to: null, marker: first[i].marker});
      for (var i = 0; i < gap; ++i)
        newMarkers.push(newHL(newText[i+1], gapMarkers));
      newMarkers.push(newHL(lst(newText), last));
    }
    return newMarkers;
  }

  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 m = markers[i].find();
      for (var j = 0; j < parts.length; ++j) {
        var p = parts[j];
        if (!posLess(m.from, p.to) || posLess(m.to, p.from)) continue;
        var newParts = [j, 1];
        if (posLess(p.from, m.from)) newParts.push({from: p.from, to: m.from});
        if (posLess(m.to, p.to)) newParts.push({from: m.to, to: p.to});
        parts.splice.apply(parts, newParts);
        j += newParts.length - 1;
      }
    }
    return parts;
  }

  function collapsedSpanAt(line, ch) {
    var sps = sawCollapsedSpans && line.markedSpans, found;
    if (sps) for (var sp, i = 0; i < sps.length; ++i) {
      sp = sps[i];
      if (!sp.marker.collapsed) continue;
      if ((sp.from == null || sp.from < ch) &&
          (sp.to == null || sp.to > ch) &&
          (!found || found.width < sp.marker.width))
        found = sp.marker;
    }
    return found;
  }
  function collapsedSpanAtStart(line) { return collapsedSpanAt(line, -1); }
  function collapsedSpanAtEnd(line) { return collapsedSpanAt(line, line.text.length + 1); }

  function visualLine(doc, line) {
    var merged;
    while (merged = collapsedSpanAtStart(line))
      line = getLine(doc, merged.find().from.line);
    return line;
  }

  function lineIsHidden(line) {
    var sps = sawCollapsedSpans && line.markedSpans;
    if (sps) for (var sp, i = 0; i < sps.length; ++i) {
      sp = sps[i];
      if (!sp.marker.collapsed) continue;
      if (sp.from == null) return true;
      if (sp.from == 0 && sp.marker.inclusiveLeft && lineIsHiddenInner(line, sp))
        return true;
    }
  }
  window.lineIsHidden = lineIsHidden;
  function lineIsHiddenInner(line, span) {
    if (span.to == null || span.marker.inclusiveRight && span.to == line.text.length)
      return true;
    for (var sp, i = 0; i < line.markedSpans.length; ++i) {
      sp = line.markedSpans[i];
      if (sp.marker.collapsed && sp.from == span.to &&
          (sp.marker.inclusiveLeft || span.marker.inclusiveRight) &&
          lineIsHiddenInner(line, sp)) return true;
    }
  }

  // hl stands for history-line, a data structure that can be either a
  // string (line without markers) or a {text, markedSpans} object.
  function hlText(val) { return typeof val == "string" ? val : val.text; }
  function hlSpans(val) {
    if (typeof val == "string") return null;
    var spans = val.markedSpans, out = null;
    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;
  }
  function newHL(text, spans) { return spans ? {text: text, markedSpans: spans} : text; }

  function detachMarkedSpans(line) {
    var spans = line.markedSpans;
    if (!spans) return;
    for (var i = 0; i < spans.length; ++i) {
      var lines = spans[i].marker.lines;
      var ix = indexOf(lines, line);
      lines.splice(ix, 1);
    }
    line.markedSpans = null;
  }

  function attachMarkedSpans(line, spans) {
    if (!spans) return;
    for (var i = 0; i < spans.length; ++i)
      spans[i].marker.lines.push(line);
    line.markedSpans = spans;
  }

  // LINE DATA STRUCTURE

  // Line objects. These hold state related to a line, including
  // highlighting info (the styles array).
  function makeLine(text, markedSpans, height) {
    var line = {text: text, height: height};
    attachMarkedSpans(line, markedSpans);
    if (lineIsHidden(line)) line.height = 0;
    return line;
  }

  function updateLine(cm, line, text, markedSpans) {
    line.text = text;
    line.stateAfter = line.styles = null;
    if (line.order != null) line.order = null;
    detachMarkedSpans(line);
    attachMarkedSpans(line, markedSpans);
    if (lineIsHidden(line)) line.height = 0;
    else if (!line.height) line.height = textHeight(cm.display);
    signalLater(cm, line, "change");
  }

  function cleanUpLine(line) {
    line.parent = null;
    detachMarkedSpans(line);
  }

  // Run the given mode's parser over a line, update the styles
  // array, which contains alternating fragments of text and CSS
  // classes.
  function highlightLine(cm, line, state) {
    var mode = cm.view.mode, flattenSpans = cm.options.flattenSpans;
    var changed = !line.styles, pos = 0, curText = "", curStyle = null;
    var stream = new StringStream(line.text, cm.options.tabSize), st = line.styles || (line.styles = []);
    if (line.text == "" && mode.blankLine) mode.blankLine(state);
    while (!stream.eol()) {
      var style = mode.token(stream, state), substr = stream.current();
      stream.start = stream.pos;
      if (!flattenSpans || curStyle != style) {
        if (curText) {
          changed = changed || pos >= st.length || curText != st[pos] || curStyle != st[pos+1];
          st[pos++] = curText; st[pos++] = curStyle;
        }
        curText = substr; curStyle = style;
      } else curText = curText + substr;
      // Give up when line is ridiculously long
      if (stream.pos > 5000) break;
    }
    if (curText) {
      changed = changed || pos >= st.length || curText != st[pos] || curStyle != st[pos+1];
      st[pos++] = curText; st[pos++] = curStyle;
    }
    if (stream.pos > 5000) { st[pos++] = line.text.slice(stream.pos); st[pos++] = null; }
    if (pos != st.length) { st.length = pos; changed = true; }
    return changed;
  }

  // Lightweight form of highlight -- proceed over this line and
  // update state, but don't save a style array.
  function processLine(cm, line, state) {
    var mode = cm.view.mode;
    var stream = new StringStream(line.text, cm.options.tabSize);
    if (line.text == "" && mode.blankLine) mode.blankLine(state);
    while (!stream.eol() && stream.pos <= 5000) {
      mode.token(stream, state);
      stream.start = stream.pos;
    }
  }

  var styleToClassCache = {};
  function styleToClass(style) {
    if (!style) return null;
    return styleToClassCache[style] ||
      (styleToClassCache[style] = "cm-" + style.replace(/ +/g, " cm-"));
  }

  function lineContent(cm, realLine, measure) {
    var merged, line = realLine, lineBefore, sawBefore, simple = true;
    while (merged = collapsedSpanAtStart(line)) {
      simple = false;
      line = getLine(cm.view.doc, merged.find().from.line);
      if (!lineBefore) lineBefore = line;
    }

    var builder = {pre: elt("pre"), col: 0, pos: 0, display: !measure,
                   measure: null, addedOne: false, cm: cm};
    if (line.textClass) builder.pre.className = line.textClass;

    do {
      if (!line.styles)
        highlightLine(cm, line, line.stateAfter = getStateBefore(cm, lineNo(line)));
      builder.measure = line == realLine && measure;
      builder.pos = 0;
      builder.addToken = builder.measure ? buildTokenMeasure : buildToken;
      if (measure && sawBefore && line != realLine && !builder.addedOne) {
        measure[0] = builder.pre.appendChild(zeroWidthElement(cm.display.measure));
        builder.addedOne = true;
      }
      var next = insertLineContent(line, builder);
      sawBefore = line == lineBefore;
      if (next) {
        line = getLine(cm.view.doc, next.to.line);
        simple = false;
      }
    } while (next);

    if (measure && !builder.addedOne)
      measure[0] = builder.pre.appendChild(simple ? elt("span", "\u00a0") : zeroWidthElement(cm.display.measure));
    if (!builder.pre.firstChild && !lineIsHidden(realLine))
      builder.pre.appendChild(document.createTextNode("\u00a0"));

    return builder.pre;
  }

  var tokenSpecialChars = /[\t\u0000-\u0019\u200b\u2028\u2029\uFEFF]/g;
  function buildToken(builder, text, style, startStyle, endStyle) {
    if (!text) return;
    if (!tokenSpecialChars.test(text)) {
      builder.col += text.length;
      var content = document.createTextNode(text);
    } else {
      var content = document.createDocumentFragment(), pos = 0;
      while (true) {
        tokenSpecialChars.lastIndex = pos;
        var m = tokenSpecialChars.exec(text);
        var skipped = m ? m.index - pos : text.length - pos;
        if (skipped) {
          content.appendChild(document.createTextNode(text.slice(pos, pos + skipped)));
          builder.col += skipped;
        }
        if (!m) break;
        pos += skipped + 1;
        if (m[0] == "\t") {
          var tabSize = builder.cm.options.tabSize, tabWidth = tabSize - builder.col % tabSize;
          content.appendChild(elt("span", spaceStr(tabWidth), "cm-tab"));
          builder.col += tabWidth;
        } else {
          var token = elt("span", "\u2022", "cm-invalidchar");
          token.title = "\\u" + m[0].charCodeAt(0).toString(16);
          content.appendChild(token);
          builder.col += 1;
        }
      }
    }
    if (style || startStyle || endStyle || builder.measure) {
      var fullStyle = style || "";
      if (startStyle) fullStyle += startStyle;
      if (endStyle) fullStyle += endStyle;
      return builder.pre.appendChild(elt("span", [content], fullStyle));
    }
    builder.pre.appendChild(content);
  }

  function buildTokenMeasure(builder, text, style, startStyle, endStyle) {
    for (var i = 0; i < text.length; ++i) {
      if (i && i < text.length - 1 &&
          builder.cm.options.lineWrapping &&
          spanAffectsWrapping.test(text.slice(i - 1, i + 1)))
        builder.pre.appendChild(elt("wbr"));
      builder.measure[builder.pos++] =
        buildToken(builder, text.charAt(i), style,
                   i == 0 && startStyle, i == text.length - 1 && endStyle);
    }
    if (text.length) builder.addedOne = true;
  }

  function buildCollapsedSpan(builder, size, widget) {
    if (widget) {
      if (!builder.display) widget = widget.cloneNode(true);
      builder.pre.appendChild(widget);
      if (builder.measure && size) {
        builder.measure[builder.pos] = widget;
        builder.addedOne = true;
      }
    }
    builder.pos += size;
  }

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

    var allText = line.text, len = allText.length;
    var pos = 0, i = 0, text = "", style;
    var nextChange = 0, spanStyle, spanEndStyle, spanStartStyle, collapsed;
    for (;;) {
      if (nextChange == pos) { // Update current marker set
        spanStyle = spanEndStyle = spanStartStyle = "";
        collapsed = null; nextChange = Infinity;
        var foundBookmark = null;
        for (var j = 0; j < spans.length; ++j) {
          var sp = spans[j], m = sp.marker;
          if (sp.from <= pos && (sp.to == null || sp.to > pos)) {
            if (sp.to != null && nextChange > sp.to) { nextChange = sp.to; spanEndStyle = ""; }
            if (m.className) spanStyle += " " + m.className;
            if (m.startStyle && sp.from == pos) spanStartStyle += " " + m.startStyle;
            if (m.endStyle && sp.to == nextChange) spanEndStyle += " " + m.endStyle;
            if (m.collapsed && (!collapsed || collapsed.marker.width < m.width))
              collapsed = sp;
          } else if (sp.from > pos && nextChange > sp.from) {
            nextChange = sp.from;
          }
          if (m.type == "bookmark" && sp.from == pos && m.replacedWith)
            foundBookmark = m.replacedWith;
        }
        if (collapsed && (collapsed.from || 0) == pos) {
          buildCollapsedSpan(builder, (collapsed.to == null ? len : collapsed.to) - pos,
                             collapsed.from != null && collapsed.marker.replacedWith);
          if (collapsed.to == null) return collapsed.marker.find();
        }
        if (foundBookmark && !collapsed) buildCollapsedSpan(builder, 0, foundBookmark);
      }
      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 + spanStyle,
                             spanStartStyle, pos + tokenText.length == nextChange ? spanEndStyle : "");
          }
          if (end >= upto) {text = text.slice(upto - pos); pos = upto; break;}
          pos = end;
          spanStartStyle = "";
        }
        text = st[i++]; style = styleToClass(st[i++]);
      }
    }
  }

  // DOCUMENT DATA STRUCTURE

  function LeafChunk(lines) {
    this.lines = lines;
    this.parent = null;
    for (var i = 0, e = lines.length, height = 0; i < e; ++i) {
      lines[i].parent = this;
      height += lines[i].height;
    }
    this.height = height;
  }

  LeafChunk.prototype = {
    chunkSize: function() { return this.lines.length; },
    remove: function(at, n, cm) {
      for (var i = at, e = at + n; i < e; ++i) {
        var line = this.lines[i];
        this.height -= line.height;
        cleanUpLine(line);
        signalLater(cm, line, "delete");
      }
      this.lines.splice(at, n);
    },
    collapse: function(lines) {
      lines.splice.apply(lines, [lines.length, 0].concat(this.lines));
    },
    insertHeight: function(at, lines, height) {
      this.height += height;
      this.lines = this.lines.slice(0, at).concat(lines).concat(this.lines.slice(at));
      for (var i = 0, e = lines.length; i < e; ++i) lines[i].parent = this;
    },
    iterN: function(at, n, op) {
      for (var e = at + n; at < e; ++at)
        if (op(this.lines[at])) return true;
    }
  };

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

  BranchChunk.prototype = {
    chunkSize: function() { return this.size; },
    remove: function(at, n, callbacks) {
      this.size -= n;
      for (var i = 0; i < this.children.length; ++i) {
        var child = this.children[i], sz = child.chunkSize();
        if (at < sz) {
          var rm = Math.min(n, sz - at), oldHeight = child.height;
          child.remove(at, rm, callbacks);
          this.height -= oldHeight - child.height;
          if (sz == rm) { this.children.splice(i--, 1); child.parent = null; }
          if ((n -= rm) == 0) break;
          at = 0;
        } else at -= sz;
      }
      if (this.size - n < 25) {
        var lines = [];
        this.collapse(lines);
        this.children = [new LeafChunk(lines)];
        this.children[0].parent = this;
      }
    },
    collapse: function(lines) {
      for (var i = 0, e = this.children.length; i < e; ++i) this.children[i].collapse(lines);
    },
    insert: function(at, lines) {
      var height = 0;
      for (var i = 0, e = lines.length; i < e; ++i) height += lines[i].height;
      this.insertHeight(at, lines, height);
    },
    insertHeight: function(at, lines, height) {
      this.size += lines.length;
      this.height += height;
      for (var i = 0, e = this.children.length; i < e; ++i) {
        var child = this.children[i], sz = child.chunkSize();
        if (at <= sz) {
          child.insertHeight(at, lines, height);
          if (child.lines && child.lines.length > 50) {
            while (child.lines.length > 50) {
              var spilled = child.lines.splice(child.lines.length - 25, 25);
              var newleaf = new LeafChunk(spilled);
              child.height -= newleaf.height;
              this.children.splice(i + 1, 0, newleaf);
              newleaf.parent = this;
            }
            this.maybeSpill();
          }
          break;
        }
        at -= sz;
      }
    },
    maybeSpill: function() {
      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();
    },
    iter: function(from, to, op) { this.iterN(from, to - from, op); },
    iterN: function(at, n, op) {
      for (var i = 0, e = this.children.length; i < e; ++i) {
        var child = this.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 UTILITIES

  function getLine(chunk, n) {
    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];
  }

  function updateLineHeight(line, height) {
    var diff = height - line.height;
    for (var n = line; n; n = n.parent) n.height += diff;
  }

  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;
  }

  function lineAtHeight(chunk, h) {
    var n = 0;
    outer: do {
      for (var i = 0, e = chunk.children.length; i < e; ++i) {
        var child = chunk.children[i], ch = child.height;
        if (h < ch) { chunk = child; continue outer; }
        h -= ch;
        n += child.chunkSize();
      }
      return n;
    } while (!chunk.lines);
    for (var i = 0, e = chunk.lines.length; i < e; ++i) {
      var line = chunk.lines[i], lh = line.height;
      if (h < lh) break;
      h -= lh;
    }
    return n + i;
  }

  function heightAtLine(cm, lineObj) {
    lineObj = visualLine(cm.view.doc, 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 = 0; i < p.children.length; ++i) {
        var cur = p.children[i];
        if (cur == chunk) break;
        else h += cur.height;
      }
    }
    return h;
  }

  function getOrder(line) {
    var order = line.order;
    if (order == null) order = line.order = bidiOrdering(line.text);
    return order;
  }

  // HISTORY

  function makeHistory() {
    return {
      // Arrays of history events. Doing something adds an event to
      // done and clears undo. Undoing moves events from done to
      // undone, redoing moves them in the other direction.
      done: [], undone: [],
      // Used to track when changes can be merged into a single undo
      // event
      lastTime: 0, lastOp: null, lastOrigin: null,
      // Used by the isClean() method
      dirtyCounter: 0
    };
  }

  function addChange(cm, start, added, old, origin, fromBefore, toBefore, fromAfter, toAfter) {
    var history = cm.view.history;
    history.undone.length = 0;
    var time = +new Date, cur = lst(history.done);
    
    if (cur &&
        (history.lastOp == cm.curOp.id ||
         history.lastOrigin == origin && (origin == "input" || origin == "delete") &&
         history.lastTime > time - 600)) {
      // Merge this change into the last event
      var last = lst(cur.events);
      if (last.start > start + old.length || last.start + last.added < start) {
        // Doesn't intersect with last sub-event, add new sub-event
        cur.events.push({start: start, added: added, old: old});
      } else {
        // Patch up the last sub-event
        var startBefore = Math.max(0, last.start - start),
        endAfter = Math.max(0, (start + old.length) - (last.start + last.added));
        for (var i = startBefore; i > 0; --i) last.old.unshift(old[i - 1]);
        for (var i = endAfter; i > 0; --i) last.old.push(old[old.length - i]);
        if (startBefore) last.start = start;
        last.added += added - (old.length - startBefore - endAfter);
      }
      cur.fromAfter = fromAfter; cur.toAfter = toAfter;
    } else {
      // Can not be merged, start a new event.
      cur = {events: [{start: start, added: added, old: old}],
             fromBefore: fromBefore, toBefore: toBefore, fromAfter: fromAfter, toAfter: toAfter};
      history.done.push(cur);
      while (history.done.length > cm.options.undoDepth)
        history.done.shift();
      if (history.dirtyCounter < 0)
          // The user has made a change after undoing past the last clean state. 
          // We can never get back to a clean state now until markClean() is called.
          history.dirtyCounter = NaN;
      else
        history.dirtyCounter++;
    }
    history.lastTime = time;
    history.lastOp = cm.curOp.id;
    history.lastOrigin = origin;
  }

  // EVENT OPERATORS

  function stopMethod() {e_stop(this);}
  // Ensure an event has a stop method.
  function addStop(event) {
    if (!event.stop) event.stop = stopMethod;
    return event;
  }

  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_stop(e) {e_preventDefault(e); e_stopPropagation(e);}
  CodeMirror.e_stop = e_stop;
  CodeMirror.e_preventDefault = e_preventDefault;
  CodeMirror.e_stopPropagation = e_stopPropagation;

  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;
  }

  // Allow 3rd-party code to override event properties by adding an override
  // object to an event object.
  function e_prop(e, prop) {
    var overridden = e.override && e.override.hasOwnProperty(prop);
    return overridden ? e.override[prop] : e[prop];
  }

  // EVENT HANDLING

  function on(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 = {});
      var arr = map[type] || (map[type] = []);
      arr.push(f);
    }
  }

  function off(emitter, type, f) {
    if (emitter.removeEventListener)
      emitter.removeEventListener(type, f, false);
    else if (emitter.detachEvent)
      emitter.detachEvent("on" + type, f);
    else {
      var arr = emitter._handlers && emitter._handlers[type];
      if (!arr) return;
      for (var i = 0; i < arr.length; ++i)
        if (arr[i] == f) { arr.splice(i, 1); break; }
    }
  }

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

  function signalLater(cm, emitter, type /*, values...*/) {
    var arr = emitter._handlers && emitter._handlers[type];
    if (!arr) return;
    var args = Array.prototype.slice.call(arguments, 3), flist = cm.curOp && cm.curOp.delayedCallbacks;
    function bnd(f) {return function(){f.apply(null, args);};};
    for (var i = 0; i < arr.length; ++i)
      if (flist) flist.push(bnd(arr[i]));
      else arr[i].apply(null, args);
  }

  function hasHandler(emitter, type) {
    var arr = emitter._handlers && emitter._handlers[type];
    return arr && arr.length > 0;
  }

  CodeMirror.on = on; CodeMirror.off = off; CodeMirror.signal = signal;

  // MISC UTILITIES

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

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

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

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

  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 selectInput(node) {
    if (ios) { // Mobile Safari apparently has a bug where select() is broken.
      node.selectionStart = 0;
      node.selectionEnd = node.value.length;
    } else node.select();
  }

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

  function emptyArray(size) {
    for (var a = [], i = 0; i < size; ++i) a.push(undefined);
    return a;
  }

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

  var nonASCIISingleCaseWordChar = /[\u3040-\u309f\u30a0-\u30ff\u3400-\u4db5\u4e00-\u9fcc]/;
  function isWordChar(ch) {
    return /\w/.test(ch) || ch > "\x80" &&
      (ch.toUpperCase() != ch.toLowerCase() || nonASCIISingleCaseWordChar.test(ch));
  }

  function isEmpty(obj) {
    var c = 0;
    for (var n in obj) if (obj.hasOwnProperty(n) && obj[n]) ++c;
    return !c;
  }

  var isExtendingChar = /[\u0300-\u036F\u0483-\u0487\u0488-\u0489\u0591-\u05BD\u05BF\u05C1-\u05C2\u05C4-\u05C5\u05C7\u0610-\u061A\u064B-\u065F\u0670\u06D6-\u06DC\u06DF-\u06E4\u06E7-\u06E8\u06EA-\u06ED\uA66F\uA670-\uA672\uA674-\uA67D\uA69F]/;

  // DOM UTILITIES

  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") setTextContent(e, content);
    else if (content) for (var i = 0; i < content.length; ++i) e.appendChild(content[i]);
    return e;
  }

  function removeChildren(e) {
    e.innerHTML = "";
    return e;
  }

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

  function setTextContent(e, str) {
    if (ie_lt9) {
      e.innerHTML = "";
      e.appendChild(document.createTextNode(str));
    } else e.textContent = str;
  }

  // FEATURE DETECTION

  // 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_lt9) return false;
    var div = elt('div');
    return "draggable" in div || "dragDrop" in div;
  }();

  // For a reason I have yet to figure out, some browsers disallow
  // word wrapping between certain characters *only* if a new inline
  // element is started between them. This makes it hard to reliably
  // measure the position of things, since that requires inserting an
  // extra span. This terribly fragile set of regexps matches the
  // character combinations that suffer from this phenomenon on the
  // various browsers.
  var spanAffectsWrapping = /^$/; // Won't match any two-character string
  if (gecko) spanAffectsWrapping = /$'/;
  else if (safari) spanAffectsWrapping = /\-[^ \-?]|\?[^ !'\"\),.\-\/:;\?\]\}]/;
  else if (chrome) spanAffectsWrapping = /\-[^ \-\.?]|\?[^ \-\.?\]\}:;!'\"\),\/]|[\.!\"#&%\)*+,:;=>\]|\}~][\(\{\[<]|\$'/;

  var knownScrollbarWidth;
  function scrollbarWidth(measure) {
    if (knownScrollbarWidth != null) return knownScrollbarWidth;
    var test = elt("div", null, null, "width: 50px; height: 50px; overflow-x: scroll");
    removeChildrenAndAdd(measure, test);
    if (test.offsetWidth)
      knownScrollbarWidth = test.offsetHeight - test.clientHeight;
    return knownScrollbarWidth || 0;
  }

  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_lt8;
    }
    if (zwspSupported) return elt("span", "\u200b");
    else return elt("span", "\u00a0", null, "display: inline-block; width: 1px; margin-right: -1px");
  }

  // See if "".split is the broken IE version, if so, provide an
  // alternative way to split lines.
  var splitLines = "\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/);};
  CodeMirror.splitLines = splitLines;

  var hasSelection = window.getSelection ? function(te) {
    try { return te.selectionStart != te.selectionEnd; }
    catch(e) { return false; }
  } : function(te) {
    try {var 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';
  })();

  // KEY NAMING

  var keyNames = {3: "Enter", 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: ";", 91: "Mod", 92: "Mod", 93: "Mod", 109: "-", 107: "=", 127: "Delete",
                  186: ";", 187: "=", 188: ",", 189: "-", 190: ".", 191: "/", 192: "`", 219: "[", 220: "\\",
                  221: "]", 222: "'", 63276: "PageUp", 63277: "PageDown", 63275: "End", 63273: "Home",
                  63234: "Left", 63232: "Up", 63235: "Right", 63233: "Down", 63302: "Insert", 63272: "Delete"};
  CodeMirror.keyNames = keyNames;
  (function() {
    // Number keys
    for (var i = 0; i < 10; i++) keyNames[i + 48] = String(i);
    // Alphabetic keys
    for (var i = 65; i <= 90; i++) keyNames[i] = String.fromCharCode(i);
    // Function keys
    for (var i = 1; i <= 12; i++) keyNames[i + 111] = keyNames[i + 63235] = "F" + i;
  })();

  // BIDI HELPERS

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

  function bidiLeft(part) { return part.level % 2 ? part.to : part.from; }
  function bidiRight(part) { return part.level % 2 ? part.from : part.to; }

  function lineLeft(line) { var order = getOrder(line); return order ? bidiLeft(order[0]) : 0; }
  function lineRight(line) {
    var order = getOrder(line);
    if (!order) return line.text.length;
    return bidiRight(lst(order));
  }

  function lineStart(cm, lineN) {
    var line = getLine(cm.view.doc, lineN);
    var visual = visualLine(cm.view.doc, line);
    if (visual != line) lineN = lineNo(visual);
    var order = getOrder(visual);
    var ch = !order ? 0 : order[0].level % 2 ? lineRight(visual) : lineLeft(visual);
    return {line: lineN, ch: ch};
  }
  function lineEnd(cm, lineNo) {
    var merged, line;
    while (merged = collapsedSpanAtEnd(line = getLine(cm.view.doc, lineNo)))
      lineNo = merged.find().to.line;
    var order = getOrder(line);
    var ch = !order ? line.text.length : order[0].level % 2 ? lineLeft(line) : lineRight(line);
    return {line: lineNo, ch: ch};
  }

  // This is somewhat involved. It is needed in order to move
  // 'visually' through bi-directional text -- i.e., pressing left
  // should make the cursor go left, even when in RTL text. The
  // tricky part is the 'jumps', where RTL and LTR text touch each
  // other. This often requires the cursor offset to move more than
  // one unit, in order to visually move one unit.
  function moveVisually(line, start, dir, byUnit) {
    var bidi = getOrder(line);
    if (!bidi) return moveLogically(line, start, dir, byUnit);
    var moveOneUnit = byUnit ? function(pos, dir) {
      do pos += dir;
      while (pos > 0 && isExtendingChar.test(line.text.charAt(pos)));
      return pos;
    } : function(pos, dir) { return pos + dir; };
    var linedir = bidi[0].level;
    for (var i = 0; i < bidi.length; ++i) {
      var part = bidi[i], sticky = part.level % 2 == linedir;
      if ((part.from < start && part.to > start) ||
          (sticky && (part.from == start || part.to == start))) break;
    }
    var target = moveOneUnit(start, part.level % 2 ? -dir : dir);

    while (target != null) {
      if (part.level % 2 == linedir) {
        if (target < part.from || target > part.to) {
          part = bidi[i += dir];
          target = part && (dir > 0 == part.level % 2 ? moveOneUnit(part.to, -1) : moveOneUnit(part.from, 1));
        } else break;
      } else {
        if (target == bidiLeft(part)) {
          part = bidi[--i];
          target = part && bidiRight(part);
        } else if (target == bidiRight(part)) {
          part = bidi[++i];
          target = part && bidiLeft(part);
        } else break;
      }
    }

    return target < 0 || target > line.text.length ? null : target;
  }

  function moveLogically(line, start, dir, byUnit) {
    var target = start + dir;
    if (byUnit) while (target > 0 && isExtendingChar.test(line.text.charAt(target))) target += dir;
    return target < 0 || target > line.text.length ? null : target;
  }

  // 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%%11NLNNN1LNNNNNLLLLLLLLLLLLLLLLLLLLLLLNLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLNLLLLLLLL";
    // Character types for codepoints 0x600 to 0x6ff
    var arabicTypes = "rrrrrrrrrrrr,rNNmmmmmmrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrmmmmmmmmmmmmmmrrrrrrrnnnnnnnnnn%nnrrrmrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrmmmmmmmmmmmmmmmmmmmNmmmmrrrrrrrrrrrrrrrrrr";
    function charType(code) {
      if (code <= 0xff) return lowTypes.charAt(code);
      else if (0x590 <= code && code <= 0x5f4) return "R";
      else if (0x600 <= code && code <= 0x6ff) return arabicTypes.charAt(code - 0x600);
      else if (0x700 <= code && code <= 0x8ac) return "r";
      else return "L";
    }

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

    return function charOrdering(str) {
      if (!bidiRE.test(str)) return false;
      var len = str.length, types = [], startType = null;
      for (var i = 0, type; i < len; ++i) {
        types.push(type = charType(str.charCodeAt(i)));
        if (startType == null) {
          if (type == "L") startType = "L";
          else if (type == "R" || type == "r") startType = "R";
        }
      }
      if (startType == null) startType = "L";

      // 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 = 0, prev = startType; i < len; ++i) {
        var type = types[i];
        if (type == "m") types[i] = 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 = 0, cur = startType; i < len; ++i) {
        var type = types[i];
        if (type == "1" && cur == "r") types[i] = "n";
        else if (isStrong.test(type)) { cur = type; if (type == "r") types[i] = "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 = 1, prev = types[0]; i < len - 1; ++i) {
        var type = types[i];
        if (type == "+" && prev == "1" && types[i+1] == "1") types[i] = "1";
        else if (type == "," && prev == types[i+1] &&
                 (prev == "1" || prev == "n")) types[i] = prev;
        prev = type;
      }

      // 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 = 0; i < len; ++i) {
        var type = types[i];
        if (type == ",") types[i] = "N";
        else if (type == "%") {
          for (var end = i + 1; end < len && types[end] == "%"; ++end) {}
          var replace = (i && types[i-1] == "!") || (end < len - 1 && types[end] == "1") ? "1" : "N";
          for (var j = i; j < end; ++j) types[j] = replace;
          i = 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 = 0, cur = startType; i < len; ++i) {
        var type = types[i];
        if (cur == "L" && type == "1") types[i] = "L";
        else if (isStrong.test(type)) cur = type;
      }

      // 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 = 0; i < len; ++i) {
        if (isNeutral.test(types[i])) {
          for (var end = i + 1; end < len && isNeutral.test(types[end]); ++end) {}
          var before = (i ? types[i-1] : startType) == "L";
          var after = (end < len - 1 ? types[end] : startType) == "L";
          var replace = before || after ? "L" : "R";
          for (var j = i; j < end; ++j) types[j] = replace;
          i = end - 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 = 0; i < len;) {
        if (countsAsLeft.test(types[i])) {
          var start = i;
          for (++i; i < len && countsAsLeft.test(types[i]); ++i) {}
          order.push({from: start, to: i, level: 0});
        } else {
          var pos = i, at = order.length;
          for (++i; i < len && types[i] != "L"; ++i) {}
          for (var j = pos; j < i;) {
            if (countsAsNum.test(types[j])) {
              if (pos < j) order.splice(at, 0, {from: pos, to: j, level: 1});
              var nstart = j;
              for (++j; j < i && countsAsNum.test(types[j]); ++j) {}
              order.splice(at, 0, {from: nstart, to: j, level: 2});
              pos = j;
            } else ++j;
          }
          if (pos < i) order.splice(at, 0, {from: pos, to: i, level: 1});
        }
      }
      if (order[0].level == 1 && (m = str.match(/^\s+/))) {
        order[0].from = m[0].length;
        order.unshift({from: 0, to: m[0].length, level: 0});
      }
      if (lst(order).level == 1 && (m = str.match(/\s+$/))) {
        lst(order).to -= m[0].length;
        order.push({from: len - m[0].length, to: len, level: 0});
      }
      if (order[0].level != lst(order).level)
        order.push({from: len, to: len, level: order[0].level});

      return order;
    };
  })();

  // THE END

  CodeMirror.version = "3.0";

  return CodeMirror;
})();