The Tor Browser / file revision

 // This is CodeMirror (http://codemirror.net), a code editor

 // implemented in JavaScript on top of the browser's DOM.

 //

 // You can find some technical background for some of the code below

 // at http://marijnhaverbeke.nl/blog/#cm-internals .

 (function(mod) {

   if (typeof exports == "object" && typeof module == "object") // CommonJS

     module.exports = mod();

   else if (typeof define == "function" && define.amd) // AMD

     return define([], mod);

   else // Plain browser env

     this.CodeMirror = mod();

 })(function() {

   "use strict";

   // BROWSER SNIFFING

   // Kludges for bugs and behavior differences that can't be feature

   // detected are enabled based on userAgent etc sniffing.

   var gecko = /gecko\/\d/i.test(navigator.userAgent);

   // ie_uptoN means Internet Explorer version N or lower

   var ie_upto10 = /MSIE \d/.test(navigator.userAgent);

   var ie_upto7 = ie_upto10 && (document.documentMode == null || document.documentMode < 8);

   var ie_upto8 = ie_upto10 && (document.documentMode == null || document.documentMode < 9);

   var ie_upto9 = ie_upto10 && (document.documentMode == null || document.documentMode < 10);

   var ie_11up = /Trident\/([7-9]|\d{2,})\./.test(navigator.userAgent);

   var ie = ie_upto10 || ie_11up;

   var webkit = /WebKit\//.test(navigator.userAgent);

   var qtwebkit = webkit && /Qt\/\d+\.\d+/.test(navigator.userAgent);

   var chrome = /Chrome\//.test(navigator.userAgent);

   var presto = /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|Opera Mobi|IEMobile/i.test(navigator.userAgent);

   var mac = ios || /Mac/.test(navigator.platform);

   var windows = /win/i.test(navigator.platform);

   var presto_version = presto && navigator.userAgent.match(/Version\/(\d*\.\d*)/);

   if (presto_version) presto_version = Number(presto_version[1]);

   if (presto_version && presto_version >= 15) { presto = false; webkit = true; }

   // Some browsers use the wrong event properties to signal cmd/ctrl on OS X

   var flipCtrlCmd = mac && (qtwebkit || presto && (presto_version == null || presto_version < 12.11));

   var captureRightClick = gecko || (ie && !ie_upto8);

   // Optimize some code when these features are not used.

   var sawReadOnlySpans = false, sawCollapsedSpans = false;

   // EDITOR CONSTRUCTOR

   // A CodeMirror instance represents an editor. This is the object

   // that user code is usually dealing with.

   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))

       options[opt] = defaults[opt];

     setGuttersForLineNumbers(options);

     var doc = options.value;

     if (typeof doc == "string") doc = new Doc(doc, options.mode);

     this.doc = doc;

     var display = this.display = new Display(place, doc);

     display.wrapper.CodeMirror = this;

     updateGutters(this);

     themeChanged(this);

     if (options.lineWrapping)

       this.display.wrapper.className += " CodeMirror-wrap";

     if (options.autofocus && !mobile) focusInput(this);

     this.state = {

       keyMaps: [],  // stores maps added by addKeyMap

       overlays: [], // highlighting overlays, as added by addOverlay

       modeGen: 0,   // bumped when mode/overlay changes, used to invalidate highlighting info

       overwrite: false, focused: false,

       suppressEdits: false, // used to disable editing during key handlers when in readOnly mode

       pasteIncoming: false, cutIncoming: false, // help recognize paste/cut edits in readInput

       draggingText: false,

       highlight: new Delayed() // stores highlight worker timeout

     };

     // Override magic textarea content restore that IE sometimes does

     // on our hidden textarea on reload

     if (ie_upto10) setTimeout(bind(resetInput, this, true), 20);

     registerEventHandlers(this);

     var cm = this;

     runInOp(this, function() {

       cm.curOp.forceUpdate = true;

       attachDoc(cm, doc);

       if ((options.autofocus && !mobile) || activeElt() == display.input)

         setTimeout(bind(onFocus, cm), 20);

       else

         onBlur(cm);

       for (var opt in optionHandlers) if (optionHandlers.hasOwnProperty(opt))

         optionHandlers[opt](cm, options[opt], Init);

       for (var i = 0; i < initHooks.length; ++i) initHooks[i](cm);

     });

   }

   // DISPLAY CONSTRUCTOR

   // The display handles the DOM integration, both for input reading

   // and content drawing. It holds references to DOM nodes and

   // display-related state.

   function Display(place, doc) {

     var d = this;

     // The semihidden textarea that is focused when the editor is

     // focused, and receives input.

     var input = d.input = elt("textarea", null, null, "position: absolute; padding: 0; width: 1px; height: 1em; outline: none");

     // The textarea is kept positioned near the cursor to prevent the

     // fact that it'll be scrolled into view on input from scrolling

     // our fake cursor out of view. On webkit, when wrap=off, paste is

     // very slow. So make the area wide instead.

     if (webkit) input.style.width = "1000px";

     else input.setAttribute("wrap", "off");

     // If border: 0; -- iOS fails to open keyboard (issue #1287)

     if (ios) input.style.border = "1px solid black";

     input.setAttribute("autocorrect", "off"); input.setAttribute("autocapitalize", "off"); input.setAttribute("spellcheck", "false");

     // Wraps and hides input textarea

     d.inputDiv = elt("div", [input], null, "overflow: hidden; position: relative; width: 3px; height: 0px;");

     // The fake scrollbar elements.

     d.scrollbarH = elt("div", [elt("div", null, null, "height: 100%; min-height: 1px")], "CodeMirror-hscrollbar");

     d.scrollbarV = elt("div", [elt("div", null, null, "min-width: 1px")], "CodeMirror-vscrollbar");

     // Covers bottom-right square when both scrollbars are present.

     d.scrollbarFiller = elt("div", null, "CodeMirror-scrollbar-filler");

     // Covers bottom of gutter when coverGutterNextToScrollbar is on

     // and h scrollbar is present.

     d.gutterFiller = elt("div", null, "CodeMirror-gutter-filler");

     // Will contain the actual code, positioned to cover the viewport.

     d.lineDiv = elt("div", null, "CodeMirror-code");

     // Elements are added to these to represent selection and cursors.

     d.selectionDiv = elt("div", null, null, "position: relative; z-index: 1");

     d.cursorDiv = elt("div", null, "CodeMirror-cursors");

     // A visibility: hidden element used to find the size of things.

     d.measure = elt("div", null, "CodeMirror-measure");

     // When lines outside of the viewport are measured, they are drawn in this.

     d.lineMeasure = elt("div", null, "CodeMirror-measure");

     // Wraps everything that needs to exist inside the vertically-padded coordinate system

     d.lineSpace = elt("div", [d.measure, d.lineMeasure, d.selectionDiv, d.cursorDiv, d.lineDiv],

                       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 document, allowing scrolling.

     d.sizer = elt("div", [d.mover], "CodeMirror-sizer");

     // Behavior of elts with overflow: auto and padding is

     // inconsistent across browsers. This is used to ensure the

     // scrollable area is big enough.

     d.heightForcer = elt("div", null, null, "position: absolute; height: " + scrollerCutOff + "px; width: 1px;");

     // Will contain the gutters, if any.

     d.gutters = elt("div", null, "CodeMirror-gutters");

     d.lineGutter = null;

     // Actual scrollable element.

     d.scroller = elt("div", [d.sizer, d.heightForcer, d.gutters], "CodeMirror-scroll");

     d.scroller.setAttribute("tabIndex", "-1");

     // The element in which the editor lives.

     d.wrapper = elt("div", [d.inputDiv, d.scrollbarH, d.scrollbarV,

                             d.scrollbarFiller, d.gutterFiller, d.scroller], "CodeMirror");

     // Work around IE7 z-index bug (not perfect, hence IE7 not really being supported)

     if (ie_upto7) { d.gutters.style.zIndex = -1; d.scroller.style.paddingRight = 0; }

     // 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).

     if (ie_upto7) d.scrollbarH.style.minHeight = d.scrollbarV.style.minWidth = "18px";

     if (place.appendChild) place.appendChild(d.wrapper);

     else place(d.wrapper);

     // Current rendered range (may be bigger than the view window).

     d.viewFrom = d.viewTo = doc.first;

     // Information about the rendered lines.

     d.view = [];

     // Holds info about a single rendered line when it was rendered

     // for measurement, while not in view.

     d.externalMeasured = null;

     // Empty space (in pixels) above the view

     d.viewOffset = 0;

     d.lastSizeC = 0;

     d.updateLineNumbers = null;

     // 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 line widget is

     // added. As an optimization, line widget aligning is skipped when

     // this is false.

     d.alignWidgets = false;

     // Flag that indicates whether we expect input to appear real soon

     // now (after some event like 'keypress' or 'input') and are

     // polling intensively.

     d.pollingFast = false;

     // Self-resetting timeout for the poller

     d.poll = new Delayed();

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

     // Tracks when resetInput has punted to just putting a short

     // string into the textarea instead of the full selection.

     d.inaccurateSelection = false;

     // Tracks the maximum line length so that the horizontal scrollbar

     // can be kept static when scrolling.

     d.maxLine = null;

     d.maxLineLength = 0;

     d.maxLineChanged = false;

     // Used for measuring wheel scrolling granularity

     d.wheelDX = d.wheelDY = d.wheelStartX = d.wheelStartY = null;

     // True when shift is held down.

     d.shift = false;

   }

   // STATE UPDATES

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

   function loadMode(cm) {

     cm.doc.mode = CodeMirror.getMode(cm.options, cm.doc.modeOption);

     resetModeState(cm);

   }

   function resetModeState(cm) {

     cm.doc.iter(function(line) {

       if (line.stateAfter) line.stateAfter = null;

       if (line.styles) line.styles = null;

     });

     cm.doc.frontier = cm.doc.first;

     startWorker(cm, 100);

     cm.state.modeGen++;

     if (cm.curOp) regChange(cm);

   }

   function wrappingChanged(cm) {

     if (cm.options.lineWrapping) {

       cm.display.wrapper.className += " CodeMirror-wrap";

       cm.display.sizer.style.minWidth = "";

     } else {

       cm.display.wrapper.className = cm.display.wrapper.className.replace(" CodeMirror-wrap", "");

       findMaxLine(cm);

     }

     estimateLineHeights(cm);

     regChange(cm);

     clearCaches(cm);

     setTimeout(function(){updateScrollbars(cm);}, 100);

   }

   // Returns a function that estimates the height of a line, to use as

   // first approximation until the line becomes visible (and is thus

   // properly measurable).

   function estimateHeight(cm) {

     var th = textHeight(cm.display), wrapping = cm.options.lineWrapping;

     var perLine = wrapping && Math.max(5, cm.display.scroller.clientWidth / charWidth(cm.display) - 3);

     return function(line) {

       if (lineIsHidden(cm.doc, line)) return 0;

       var widgetsHeight = 0;

       if (line.widgets) for (var i = 0; i < line.widgets.length; i++) {

         if (line.widgets[i].height) widgetsHeight += line.widgets[i].height;

       }

       if (wrapping)

         return widgetsHeight + (Math.ceil(line.text.length / perLine) || 1) * th;

       else

         return widgetsHeight + th;

     };

   }

   function estimateLineHeights(cm) {

     var doc = cm.doc, est = estimateHeight(cm);

     doc.iter(function(line) {

       var estHeight = est(line);

       if (estHeight != line.height) updateLineHeight(line, estHeight);

     });

   }

   function keyMapChanged(cm) {

     var map = keyMap[cm.options.keyMap], style = map.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);

     regChange(cm);

     setTimeout(function(){alignHorizontally(cm);}, 20);

   }

   // Rebuild the gutter elements, ensure the margin to the left of the

   // code matches their width.

   function updateGutters(cm) {

     var gutters = cm.display.gutters, specs = cm.options.gutters;

     removeChildren(gutters);

     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";

     var width = gutters.offsetWidth;

     cm.display.sizer.style.marginLeft = width + "px";

     if (i) cm.display.scrollbarH.style.left = cm.options.fixedGutter ? width + "px" : 0;

   }

   // Compute the character length of a line, taking into account

   // collapsed ranges (see markText) that might hide parts, and join

   // other lines onto it.

   function lineLength(line) {

     if (line.height == 0) return 0;

     var len = line.text.length, merged, cur = line;

     while (merged = collapsedSpanAtStart(cur)) {

       var found = merged.find(0, true);

       cur = found.from.line;

       len += found.from.ch - found.to.ch;

     }

     cur = line;

     while (merged = collapsedSpanAtEnd(cur)) {

       var found = merged.find(0, true);

       len -= cur.text.length - found.from.ch;

       cur = found.to.line;

       len += cur.text.length - found.to.ch;

     }

     return len;

   }

   // Find the longest line in the document.

   function findMaxLine(cm) {

     var d = cm.display, doc = cm.doc;

     d.maxLine = getLine(doc, doc.first);

     d.maxLineLength = lineLength(d.maxLine);

     d.maxLineChanged = true;

     doc.iter(function(line) {

       var len = lineLength(line);

       if (len > d.maxLineLength) {

         d.maxLineLength = len;

         d.maxLine = line;

       }

     });

   }

   // Make sure the gutters options contains the element

   // "CodeMirror-linenumbers" when the lineNumbers option is true.

   function setGuttersForLineNumbers(options) {

     var found = indexOf(options.gutters, "CodeMirror-linenumbers");

     if (found == -1 && options.lineNumbers) {

       options.gutters = options.gutters.concat(["CodeMirror-linenumbers"]);

     } else if (found > -1 && !options.lineNumbers) {

       options.gutters = options.gutters.slice(0);

       options.gutters.splice(found, 1);

     }

   }

   // SCROLLBARS

   // Prepare DOM reads needed to update the scrollbars. Done in one

   // shot to minimize update/measure roundtrips.

   function measureForScrollbars(cm) {

     var scroll = cm.display.scroller;

     return {

       clientHeight: scroll.clientHeight,

       barHeight: cm.display.scrollbarV.clientHeight,

       scrollWidth: scroll.scrollWidth, clientWidth: scroll.clientWidth,

       barWidth: cm.display.scrollbarH.clientWidth,

       docHeight: Math.round(cm.doc.height + paddingVert(cm.display))

     };

   }

   // Re-synchronize the fake scrollbars with the actual size of the

   // content.

   function updateScrollbars(cm, measure) {

     if (!measure) measure = measureForScrollbars(cm);

     var d = cm.display;

     var scrollHeight = measure.docHeight + scrollerCutOff;

     var needsH = measure.scrollWidth > measure.clientWidth;

     var needsV = scrollHeight > measure.clientHeight;

     if (needsV) {

       d.scrollbarV.style.display = "block";

       d.scrollbarV.style.bottom = needsH ? scrollbarWidth(d.measure) + "px" : "0";

       // A bug in IE8 can cause this value to be negative, so guard it.

       d.scrollbarV.firstChild.style.height =

         Math.max(0, scrollHeight - measure.clientHeight + (measure.barHeight || d.scrollbarV.clientHeight)) + "px";

     } else {

       d.scrollbarV.style.display = "";

       d.scrollbarV.firstChild.style.height = "0";

     }

     if (needsH) {

       d.scrollbarH.style.display = "block";

       d.scrollbarH.style.right = needsV ? scrollbarWidth(d.measure) + "px" : "0";

       d.scrollbarH.firstChild.style.width =

         (measure.scrollWidth - measure.clientWidth + (measure.barWidth || d.scrollbarH.clientWidth)) + "px";

     } else {

       d.scrollbarH.style.display = "";

       d.scrollbarH.firstChild.style.width = "0";

     }

     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 (needsH && cm.options.coverGutterNextToScrollbar && cm.options.fixedGutter) {

       d.gutterFiller.style.display = "block";

       d.gutterFiller.style.height = scrollbarWidth(d.measure) + "px";

       d.gutterFiller.style.width = d.gutters.offsetWidth + "px";

     } else d.gutterFiller.style.display = "";

     if (mac_geLion && scrollbarWidth(d.measure) === 0) {

       d.scrollbarV.style.minWidth = d.scrollbarH.style.minHeight = mac_geMountainLion ? "18px" : "12px";

       var barMouseDown = function(e) {

         if (e_target(e) != d.scrollbarV && e_target(e) != d.scrollbarH)

           operation(cm, onMouseDown)(e);

       };

       on(d.scrollbarV, "mousedown", barMouseDown);

       on(d.scrollbarH, "mousedown", barMouseDown);

     }

   }

   // Compute the lines that are visible in a given viewport (defaults

   // the the current scroll position). viewPort may contain top,

   // height, and ensure (see op.scrollToPos) properties.

   function visibleLines(display, doc, viewPort) {

     var top = viewPort && viewPort.top != null ? viewPort.top : display.scroller.scrollTop;

     top = Math.floor(top - paddingTop(display));

     var bottom = viewPort && viewPort.bottom != null ? viewPort.bottom : top + display.wrapper.clientHeight;

     var from = lineAtHeight(doc, top), to = lineAtHeight(doc, bottom);

     // Ensure is a {from: {line, ch}, to: {line, ch}} object, and

     // forces those lines into the viewport (if possible).

     if (viewPort && viewPort.ensure) {

       var ensureFrom = viewPort.ensure.from.line, ensureTo = viewPort.ensure.to.line;

       if (ensureFrom < from)

         return {from: ensureFrom,

                 to: lineAtHeight(doc, heightAtLine(getLine(doc, ensureFrom)) + display.wrapper.clientHeight)};

       if (Math.min(ensureTo, doc.lastLine()) >= to)

         return {from: lineAtHeight(doc, heightAtLine(getLine(doc, ensureTo)) - display.wrapper.clientHeight),

                 to: ensureTo};

     }

     return {from: from, to: to};

   }

   // LINE NUMBERS

   // Re-align line numbers and gutter marks to compensate for

   // horizontal scrolling.

   function alignHorizontally(cm) {

     var display = cm.display, view = display.view;

     if (!display.alignWidgets && (!display.gutters.firstChild || !cm.options.fixedGutter)) return;

     var comp = compensateForHScroll(display) - display.scroller.scrollLeft + cm.doc.scrollLeft;

     var gutterW = display.gutters.offsetWidth, left = comp + "px";

     for (var i = 0; i < view.length; i++) if (!view[i].hidden) {

       if (cm.options.fixedGutter && view[i].gutter)

         view[i].gutter.style.left = left;

       var align = view[i].alignable;

       if (align) for (var j = 0; j < align.length; j++)

         align[j].style.left = left;

     }

     if (cm.options.fixedGutter)

       display.gutters.style.left = (comp + gutterW) + "px";

   }

   // Used to ensure that the line number gutter is still the right

   // size for the current document size. Returns true when an update

   // is needed.

   function maybeUpdateLineNumberWidth(cm) {

     if (!cm.options.lineNumbers) return false;

     var doc = cm.doc, last = lineNumberFor(cm.options, doc.first + doc.size - 1), display = cm.display;

     if (last.length != display.lineNumChars) {

       var test = display.measure.appendChild(elt("div", [elt("div", last)],

                                                  "CodeMirror-linenumber CodeMirror-gutter-elt"));

       var innerW = test.firstChild.offsetWidth, padding = test.offsetWidth - innerW;

       display.lineGutter.style.width = "";

       display.lineNumInnerWidth = Math.max(innerW, display.lineGutter.offsetWidth - padding);

       display.lineNumWidth = display.lineNumInnerWidth + padding;

       display.lineNumChars = display.lineNumInnerWidth ? last.length : -1;

       display.lineGutter.style.width = display.lineNumWidth + "px";

       var width = display.gutters.offsetWidth;

       display.scrollbarH.style.left = cm.options.fixedGutter ? width + "px" : 0;

       display.sizer.style.marginLeft = width + "px";

       return true;

     }

     return false;

   }

   function lineNumberFor(options, i) {

     return String(options.lineNumberFormatter(i + options.firstLineNumber));

   }

   // Computes display.scroller.scrollLeft + display.gutters.offsetWidth,

   // but using getBoundingClientRect to get a sub-pixel-accurate

   // result.

   function compensateForHScroll(display) {

     return display.scroller.getBoundingClientRect().left - display.sizer.getBoundingClientRect().left;

   }

   // DISPLAY DRAWING

   // Updates the display, selection, and scrollbars, using the

   // information in display.view to find out which nodes are no longer

   // up-to-date. Tries to bail out early when no changes are needed,

   // unless forced is true.

   // Returns true if an actual update happened, false otherwise.

   function updateDisplay(cm, viewPort, forced) {

     var oldFrom = cm.display.viewFrom, oldTo = cm.display.viewTo, updated;

     var visible = visibleLines(cm.display, cm.doc, viewPort);

     for (var first = true;; first = false) {

       var oldWidth = cm.display.scroller.clientWidth;

       if (!updateDisplayInner(cm, visible, forced)) break;

       updated = true;

       // If the max line changed since it was last measured, measure it,

       // and ensure the document's width matches it.

       if (cm.display.maxLineChanged && !cm.options.lineWrapping)

         adjustContentWidth(cm);

       var barMeasure = measureForScrollbars(cm);

       updateSelection(cm);

       setDocumentHeight(cm, barMeasure);

       updateScrollbars(cm, barMeasure);

       if (first && cm.options.lineWrapping && oldWidth != cm.display.scroller.clientWidth) {

         forced = true;

         continue;

       }

       forced = false;

       // Clip forced viewport to actual scrollable area.

       if (viewPort && viewPort.top != null)

         viewPort = {top: Math.min(barMeasure.docHeight - scrollerCutOff - barMeasure.clientHeight, viewPort.top)};

       // Updated line heights might result in the drawn area not

       // actually covering the viewport. Keep looping until it does.

       visible = visibleLines(cm.display, cm.doc, viewPort);

       if (visible.from >= cm.display.viewFrom && visible.to <= cm.display.viewTo)

         break;

     }

     cm.display.updateLineNumbers = null;

     if (updated) {

       signalLater(cm, "update", cm);

       if (cm.display.viewFrom != oldFrom || cm.display.viewTo != oldTo)

         signalLater(cm, "viewportChange", cm, cm.display.viewFrom, cm.display.viewTo);

     }

     return updated;

   }

   // Does the actual updating of the line display. Bails out

   // (returning false) when there is nothing to be done and forced is

   // false.

   function updateDisplayInner(cm, visible, forced) {

     var display = cm.display, doc = cm.doc;

     if (!display.wrapper.offsetWidth) {

       resetView(cm);

       return;

     }

     // Bail out if the visible area is already rendered and nothing changed.

     if (!forced && visible.from >= display.viewFrom && visible.to <= display.viewTo &&

         countDirtyView(cm) == 0)

       return;

     if (maybeUpdateLineNumberWidth(cm))

       resetView(cm);

     var dims = getDimensions(cm);

     // Compute a suitable new viewport (from & to)

     var end = doc.first + doc.size;

     var from = Math.max(visible.from - cm.options.viewportMargin, doc.first);

     var to = Math.min(end, visible.to + cm.options.viewportMargin);

     if (display.viewFrom < from && from - display.viewFrom < 20) from = Math.max(doc.first, display.viewFrom);

     if (display.viewTo > to && display.viewTo - to < 20) to = Math.min(end, display.viewTo);

     if (sawCollapsedSpans) {

       from = visualLineNo(cm.doc, from);

       to = visualLineEndNo(cm.doc, to);

     }

     var different = from != display.viewFrom || to != display.viewTo ||

       display.lastSizeC != display.wrapper.clientHeight;

     adjustView(cm, from, to);

     display.viewOffset = heightAtLine(getLine(cm.doc, display.viewFrom));

     // Position the mover div to align with the current scroll position

     cm.display.mover.style.top = display.viewOffset + "px";

     var toUpdate = countDirtyView(cm);

     if (!different && toUpdate == 0 && !forced) return;

     // For big changes, we hide the enclosing element during the

     // update, since that speeds up the operations on most browsers.

     var focused = activeElt();

     if (toUpdate > 4) display.lineDiv.style.display = "none";

     patchDisplay(cm, display.updateLineNumbers, dims);

     if (toUpdate > 4) display.lineDiv.style.display = "";

     // There might have been a widget with a focused element that got

     // hidden or updated, if so re-focus it.

     if (focused && activeElt() != focused && focused.offsetHeight) focused.focus();

     // Prevent selection and cursors from interfering with the scroll

     // width.

     removeChildren(display.cursorDiv);

     removeChildren(display.selectionDiv);

     if (different) {

       display.lastSizeC = display.wrapper.clientHeight;

       startWorker(cm, 400);

     }

     updateHeightsInViewport(cm);

     return true;

   }

   function adjustContentWidth(cm) {

     var display = cm.display;

     var width = measureChar(cm, display.maxLine, display.maxLine.text.length).left;

     display.maxLineChanged = false;

     var minWidth = Math.max(0, width + 3);

     var maxScrollLeft = Math.max(0, display.sizer.offsetLeft + minWidth + scrollerCutOff - display.scroller.clientWidth);

     display.sizer.style.minWidth = minWidth + "px";

     if (maxScrollLeft < cm.doc.scrollLeft)

       setScrollLeft(cm, Math.min(display.scroller.scrollLeft, maxScrollLeft), true);

   }

   function setDocumentHeight(cm, measure) {

     cm.display.sizer.style.minHeight = cm.display.heightForcer.style.top = measure.docHeight + "px";

     cm.display.gutters.style.height = Math.max(measure.docHeight, measure.clientHeight - scrollerCutOff) + "px";

   }

   // Read the actual heights of the rendered lines, and update their

   // stored heights to match.

   function updateHeightsInViewport(cm) {

     var display = cm.display;

     var prevBottom = display.lineDiv.offsetTop;

     for (var i = 0; i < display.view.length; i++) {

       var cur = display.view[i], height;

       if (cur.hidden) continue;

       if (ie_upto7) {

         var bot = cur.node.offsetTop + cur.node.offsetHeight;

         height = bot - prevBottom;

         prevBottom = bot;

       } else {

         var box = cur.node.getBoundingClientRect();

         height = box.bottom - box.top;

       }

       var diff = cur.line.height - height;

       if (height < 2) height = textHeight(display);

       if (diff > .001 || diff < -.001) {

         updateLineHeight(cur.line, height);

         updateWidgetHeight(cur.line);

         if (cur.rest) for (var j = 0; j < cur.rest.length; j++)

           updateWidgetHeight(cur.rest[j]);

       }

     }

   }

   // Read and store the height of line widgets associated with the

   // given line.

   function updateWidgetHeight(line) {

     if (line.widgets) for (var i = 0; i < line.widgets.length; ++i)

       line.widgets[i].height = line.widgets[i].node.offsetHeight;

   }

   // Do a bulk-read of the DOM positions and sizes needed to draw the

   // view, so that we don't interleave reading and writing to the DOM.

   function getDimensions(cm) {

     var d = cm.display, left = {}, width = {};

     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};

   }

   // Sync the actual display DOM structure with display.view, removing

   // nodes for lines that are no longer in view, and creating the ones

   // that are not there yet, and updating the ones that are out of

   // date.

   function patchDisplay(cm, updateNumbersFrom, dims) {

     var display = cm.display, lineNumbers = cm.options.lineNumbers;

     var container = display.lineDiv, cur = container.firstChild;

     function rm(node) {

       var next = node.nextSibling;

       // Works around a throw-scroll bug in OS X Webkit

       if (webkit && mac && cm.display.currentWheelTarget == node)

         node.style.display = "none";

       else

         node.parentNode.removeChild(node);

       return next;

     }

     var view = display.view, lineN = display.viewFrom;

     // Loop over the elements in the view, syncing cur (the DOM nodes

     // in display.lineDiv) with the view as we go.

     for (var i = 0; i < view.length; i++) {

       var lineView = view[i];

       if (lineView.hidden) {

       } else if (!lineView.node) { // Not drawn yet

         var node = buildLineElement(cm, lineView, lineN, dims);

         container.insertBefore(node, cur);

       } else { // Already drawn

         while (cur != lineView.node) cur = rm(cur);

         var updateNumber = lineNumbers && updateNumbersFrom != null &&

           updateNumbersFrom <= lineN && lineView.lineNumber;

         if (lineView.changes) {

           if (indexOf(lineView.changes, "gutter") > -1) updateNumber = false;

           updateLineForChanges(cm, lineView, lineN, dims);

         }

         if (updateNumber) {

           removeChildren(lineView.lineNumber);

           lineView.lineNumber.appendChild(document.createTextNode(lineNumberFor(cm.options, lineN)));

         }

         cur = lineView.node.nextSibling;

       }

       lineN += lineView.size;

     }

     while (cur) cur = rm(cur);

   }

   // When an aspect of a line changes, a string is added to

   // lineView.changes. This updates the relevant part of the line's

   // DOM structure.

   function updateLineForChanges(cm, lineView, lineN, dims) {

     for (var j = 0; j < lineView.changes.length; j++) {

       var type = lineView.changes[j];

       if (type == "text") updateLineText(cm, lineView);

       else if (type == "gutter") updateLineGutter(cm, lineView, lineN, dims);

       else if (type == "class") updateLineClasses(lineView);

       else if (type == "widget") updateLineWidgets(lineView, dims);

     }

     lineView.changes = null;

   }

   // Lines with gutter elements, widgets or a background class need to

   // be wrapped, and have the extra elements added to the wrapper div

   function ensureLineWrapped(lineView) {

     if (lineView.node == lineView.text) {

       lineView.node = elt("div", null, null, "position: relative");

       if (lineView.text.parentNode)

         lineView.text.parentNode.replaceChild(lineView.node, lineView.text);

       lineView.node.appendChild(lineView.text);

       if (ie_upto7) lineView.node.style.zIndex = 2;

     }

     return lineView.node;

   }

   function updateLineBackground(lineView) {

     var cls = lineView.bgClass ? lineView.bgClass + " " + (lineView.line.bgClass || "") : lineView.line.bgClass;

     if (cls) cls += " CodeMirror-linebackground";

     if (lineView.background) {

       if (cls) lineView.background.className = cls;

       else { lineView.background.parentNode.removeChild(lineView.background); lineView.background = null; }

     } else if (cls) {

       var wrap = ensureLineWrapped(lineView);

       lineView.background = wrap.insertBefore(elt("div", null, cls), wrap.firstChild);

     }

   }

   // Wrapper around buildLineContent which will reuse the structure

   // in display.externalMeasured when possible.

   function getLineContent(cm, lineView) {

     var ext = cm.display.externalMeasured;

     if (ext && ext.line == lineView.line) {

       cm.display.externalMeasured = null;

       lineView.measure = ext.measure;

       return ext.built;

     }

     return buildLineContent(cm, lineView);

   }

   // Redraw the line's text. Interacts with the background and text

   // classes because the mode may output tokens that influence these

   // classes.

   function updateLineText(cm, lineView) {

     var cls = lineView.text.className;

     var built = getLineContent(cm, lineView);

     if (lineView.text == lineView.node) lineView.node = built.pre;

     lineView.text.parentNode.replaceChild(built.pre, lineView.text);

     lineView.text = built.pre;

     if (built.bgClass != lineView.bgClass || built.textClass != lineView.textClass) {

       lineView.bgClass = built.bgClass;

       lineView.textClass = built.textClass;

       updateLineClasses(lineView);

     } else if (cls) {

       lineView.text.className = cls;

     }

   }

   function updateLineClasses(lineView) {

     updateLineBackground(lineView);

     if (lineView.line.wrapClass)

       ensureLineWrapped(lineView).className = lineView.line.wrapClass;

     else if (lineView.node != lineView.text)

       lineView.node.className = "";

     var textClass = lineView.textClass ? lineView.textClass + " " + (lineView.line.textClass || "") : lineView.line.textClass;

     lineView.text.className = textClass || "";

   }

   function updateLineGutter(cm, lineView, lineN, dims) {

     if (lineView.gutter) {

       lineView.node.removeChild(lineView.gutter);

       lineView.gutter = null;

     }

     var markers = lineView.line.gutterMarkers;

     if (cm.options.lineNumbers || markers) {

       var wrap = ensureLineWrapped(lineView);

       var gutterWrap = lineView.gutter =

         wrap.insertBefore(elt("div", null, "CodeMirror-gutter-wrapper", "position: absolute; left: " +

                               (cm.options.fixedGutter ? dims.fixedPos : -dims.gutterTotalWidth) + "px"),

                           lineView.text);

       if (cm.options.lineNumbers && (!markers || !markers["CodeMirror-linenumbers"]))

         lineView.lineNumber = gutterWrap.appendChild(

           elt("div", lineNumberFor(cm.options, lineN),

               "CodeMirror-linenumber CodeMirror-gutter-elt",

               "left: " + dims.gutterLeft["CodeMirror-linenumbers"] + "px; width: "

               + cm.display.lineNumInnerWidth + "px"));

       if (markers) for (var k = 0; k < cm.options.gutters.length; ++k) {

         var id = cm.options.gutters[k], found = markers.hasOwnProperty(id) && markers[id];

         if (found)

           gutterWrap.appendChild(elt("div", [found], "CodeMirror-gutter-elt", "left: " +

                                      dims.gutterLeft[id] + "px; width: " + dims.gutterWidth[id] + "px"));

       }

     }

   }

   function updateLineWidgets(lineView, dims) {

     if (lineView.alignable) lineView.alignable = null;

     for (var node = lineView.node.firstChild, next; node; node = next) {

       var next = node.nextSibling;

       if (node.className == "CodeMirror-linewidget")

         lineView.node.removeChild(node);

     }

     insertLineWidgets(lineView, dims);

   }

   // Build a line's DOM representation from scratch

   function buildLineElement(cm, lineView, lineN, dims) {

     var built = getLineContent(cm, lineView);

     lineView.text = lineView.node = built.pre;

     if (built.bgClass) lineView.bgClass = built.bgClass;

     if (built.textClass) lineView.textClass = built.textClass;

     updateLineClasses(lineView);

     updateLineGutter(cm, lineView, lineN, dims);

     insertLineWidgets(lineView, dims);

     return lineView.node;

   }

   // A lineView may contain multiple logical lines (when merged by

   // collapsed spans). The widgets for all of them need to be drawn.

   function insertLineWidgets(lineView, dims) {

     insertLineWidgetsFor(lineView.line, lineView, dims, true);

     if (lineView.rest) for (var i = 0; i < lineView.rest.length; i++)

       insertLineWidgetsFor(lineView.rest[i], lineView, dims, false);

   }

   function insertLineWidgetsFor(line, lineView, dims, allowAbove) {

     if (!line.widgets) return;

     var wrap = ensureLineWrapped(lineView);

     for (var i = 0, ws = line.widgets; i < ws.length; ++i) {

       var widget = ws[i], node = elt("div", [widget.node], "CodeMirror-linewidget");

       if (!widget.handleMouseEvents) node.ignoreEvents = true;

       positionLineWidget(widget, node, lineView, dims);

       if (allowAbove && widget.above)

         wrap.insertBefore(node, lineView.gutter || lineView.text);

       else

         wrap.appendChild(node);

       signalLater(widget, "redraw");

     }

   }

   function positionLineWidget(widget, node, lineView, dims) {

     if (widget.noHScroll) {

       (lineView.alignable || (lineView.alignable = [])).push(node);

       var width = dims.wrapperWidth;

       node.style.left = dims.fixedPos + "px";

       if (!widget.coverGutter) {

         width -= dims.gutterTotalWidth;

         node.style.paddingLeft = dims.gutterTotalWidth + "px";

       }

       node.style.width = width + "px";

     }

     if (widget.coverGutter) {

       node.style.zIndex = 5;

       node.style.position = "relative";

       if (!widget.noHScroll) node.style.marginLeft = -dims.gutterTotalWidth + "px";

     }

   }

   // POSITION OBJECT

   // A Pos instance represents a position within the text.

   var Pos = CodeMirror.Pos = function(line, ch) {

     if (!(this instanceof Pos)) return new Pos(line, ch);

     this.line = line; this.ch = ch;

   };

   // Compare two positions, return 0 if they are the same, a negative

   // number when a is less, and a positive number otherwise.

   var cmp = CodeMirror.cmpPos = function(a, b) { return a.line - b.line || a.ch - b.ch; };

   function copyPos(x) {return Pos(x.line, x.ch);}

   function maxPos(a, b) { return cmp(a, b) < 0 ? b : a; }

   function minPos(a, b) { return cmp(a, b) < 0 ? a : b; }

   // SELECTION / CURSOR

   // Selection objects are immutable. A new one is created every time

   // the selection changes. A selection is one or more non-overlapping

   // (and non-touching) ranges, sorted, and an integer that indicates

   // which one is the primary selection (the one that's scrolled into

   // view, that getCursor returns, etc).

   function Selection(ranges, primIndex) {

     this.ranges = ranges;

     this.primIndex = primIndex;

   }

   Selection.prototype = {

     primary: function() { return this.ranges[this.primIndex]; },

     equals: function(other) {

       if (other == this) return true;

       if (other.primIndex != this.primIndex || other.ranges.length != this.ranges.length) return false;

       for (var i = 0; i < this.ranges.length; i++) {

         var here = this.ranges[i], there = other.ranges[i];

         if (cmp(here.anchor, there.anchor) != 0 || cmp(here.head, there.head) != 0) return false;

       }

       return true;

     },

     deepCopy: function() {

       for (var out = [], i = 0; i < this.ranges.length; i++)

         out[i] = new Range(copyPos(this.ranges[i].anchor), copyPos(this.ranges[i].head));

       return new Selection(out, this.primIndex);

     },

     somethingSelected: function() {

       for (var i = 0; i < this.ranges.length; i++)

         if (!this.ranges[i].empty()) return true;

       return false;

     },

     contains: function(pos, end) {

       if (!end) end = pos;

       for (var i = 0; i < this.ranges.length; i++) {

         var range = this.ranges[i];

         if (cmp(end, range.from()) >= 0 && cmp(pos, range.to()) <= 0)

           return i;

       }

       return -1;

     }

   };

   function Range(anchor, head) {

     this.anchor = anchor; this.head = head;

   }

   Range.prototype = {

     from: function() { return minPos(this.anchor, this.head); },

     to: function() { return maxPos(this.anchor, this.head); },

     empty: function() {

       return this.head.line == this.anchor.line && this.head.ch == this.anchor.ch;

     }

   };

   // Take an unsorted, potentially overlapping set of ranges, and

   // build a selection out of it. 'Consumes' ranges array (modifying

   // it).

   function normalizeSelection(ranges, primIndex) {

     var prim = ranges[primIndex];

     ranges.sort(function(a, b) { return cmp(a.from(), b.from()); });

     primIndex = indexOf(ranges, prim);

     for (var i = 1; i < ranges.length; i++) {

       var cur = ranges[i], prev = ranges[i - 1];

       if (cmp(prev.to(), cur.from()) >= 0) {

         var from = minPos(prev.from(), cur.from()), to = maxPos(prev.to(), cur.to());

         var inv = prev.empty() ? cur.from() == cur.head : prev.from() == prev.head;

         if (i <= primIndex) --primIndex;

         ranges.splice(--i, 2, new Range(inv ? to : from, inv ? from : to));

       }

     }

     return new Selection(ranges, primIndex);

   }

   function simpleSelection(anchor, head) {

     return new Selection([new Range(anchor, head || anchor)], 0);

   }

   // Most of the external API clips given positions to make sure they

   // actually exist within the document.

   function clipLine(doc, n) {return Math.max(doc.first, Math.min(n, doc.first + doc.size - 1));}

   function clipPos(doc, pos) {

     if (pos.line < doc.first) return Pos(doc.first, 0);

     var last = doc.first + doc.size - 1;

     if (pos.line > last) return Pos(last, getLine(doc, last).text.length);

     return clipToLen(pos, getLine(doc, pos.line).text.length);

   }

   function clipToLen(pos, linelen) {

     var ch = pos.ch;

     if (ch == null || ch > linelen) return Pos(pos.line, linelen);

     else if (ch < 0) return Pos(pos.line, 0);

     else return pos;

   }

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

   function clipPosArray(doc, array) {

     for (var out = [], i = 0; i < array.length; i++) out[i] = clipPos(doc, array[i]);

     return out;

   }

   // SELECTION UPDATES

   // The 'scroll' parameter given to many of these indicated whether

   // the new cursor position should be scrolled into view after

   // modifying the selection.

   // If shift is held or the extend flag is set, extends a range to

   // include a given position (and optionally a second position).

   // Otherwise, simply returns the range between the given positions.

   // Used for cursor motion and such.

   function extendRange(doc, range, head, other) {

     if (doc.cm && doc.cm.display.shift || doc.extend) {

       var anchor = range.anchor;

       if (other) {

         var posBefore = cmp(head, anchor) < 0;

         if (posBefore != (cmp(other, anchor) < 0)) {

           anchor = head;

           head = other;

         } else if (posBefore != (cmp(head, other) < 0)) {

           head = other;

         }

       }

       return new Range(anchor, head);

     } else {

       return new Range(other || head, head);

     }

   }

   // Extend the primary selection range, discard the rest.

   function extendSelection(doc, head, other, options) {

     setSelection(doc, new Selection([extendRange(doc, doc.sel.primary(), head, other)], 0), options);

   }

   // Extend all selections (pos is an array of selections with length

   // equal the number of selections)

   function extendSelections(doc, heads, options) {

     for (var out = [], i = 0; i < doc.sel.ranges.length; i++)

       out[i] = extendRange(doc, doc.sel.ranges[i], heads[i], null);

     var newSel = normalizeSelection(out, doc.sel.primIndex);

     setSelection(doc, newSel, options);

   }

   // Updates a single range in the selection.

   function replaceOneSelection(doc, i, range, options) {

     var ranges = doc.sel.ranges.slice(0);

     ranges[i] = range;

     setSelection(doc, normalizeSelection(ranges, doc.sel.primIndex), options);

   }

   // Reset the selection to a single range.

   function setSimpleSelection(doc, anchor, head, options) {

     setSelection(doc, simpleSelection(anchor, head), options);

   }

   // Give beforeSelectionChange handlers a change to influence a

   // selection update.

   function filterSelectionChange(doc, sel) {

     var obj = {

       ranges: sel.ranges,

       update: function(ranges) {

         this.ranges = [];

         for (var i = 0; i < ranges.length; i++)

           this.ranges[i] = new Range(clipPos(doc, ranges[i].anchor),

                                      clipPos(doc, ranges[i].head));

       }

     };

     signal(doc, "beforeSelectionChange", doc, obj);

     if (doc.cm) signal(doc.cm, "beforeSelectionChange", doc.cm, obj);

     if (obj.ranges != sel.ranges) return normalizeSelection(obj.ranges, obj.ranges.length - 1);

     else return sel;

   }

   function setSelectionReplaceHistory(doc, sel, options) {

     var done = doc.history.done, last = lst(done);

     if (last && last.ranges) {

       done[done.length - 1] = sel;

       setSelectionNoUndo(doc, sel, options);

     } else {

       setSelection(doc, sel, options);

     }

   }

   // Set a new selection.

   function setSelection(doc, sel, options) {

     setSelectionNoUndo(doc, sel, options);

     addSelectionToHistory(doc, doc.sel, doc.cm ? doc.cm.curOp.id : NaN, options);

   }

   function setSelectionNoUndo(doc, sel, options) {

     if (hasHandler(doc, "beforeSelectionChange") || doc.cm && hasHandler(doc.cm, "beforeSelectionChange"))

       sel = filterSelectionChange(doc, sel);

     var bias = cmp(sel.primary().head, doc.sel.primary().head) < 0 ? -1 : 1;

     setSelectionInner(doc, skipAtomicInSelection(doc, sel, bias, true));

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

       ensureCursorVisible(doc.cm);

   }

   function setSelectionInner(doc, sel) {

     if (sel.equals(doc.sel)) return;

     doc.sel = sel;

     if (doc.cm)

       doc.cm.curOp.updateInput = doc.cm.curOp.selectionChanged =

         doc.cm.curOp.cursorActivity = true;

     signalLater(doc, "cursorActivity", doc);

   }

   // Verify that the selection does not partially select any atomic

   // marked ranges.

   function reCheckSelection(doc) {

     setSelectionInner(doc, skipAtomicInSelection(doc, doc.sel, null, false), sel_dontScroll);

   }

   // Return a selection that does not partially select any atomic

   // ranges.

   function skipAtomicInSelection(doc, sel, bias, mayClear) {

     var out;

     for (var i = 0; i < sel.ranges.length; i++) {

       var range = sel.ranges[i];

       var newAnchor = skipAtomic(doc, range.anchor, bias, mayClear);

       var newHead = skipAtomic(doc, range.head, bias, mayClear);

       if (out || newAnchor != range.anchor || newHead != range.head) {

         if (!out) out = sel.ranges.slice(0, i);

         out[i] = new Range(newAnchor, newHead);

       }

     }

     return out ? normalizeSelection(out, sel.primIndex) : sel;

   }

   // Ensure a given position is not inside an atomic range.

   function skipAtomic(doc, pos, bias, mayClear) {

     var flipped = false, curPos = pos;

     var dir = bias || 1;

     doc.cantEdit = false;

     search: for (;;) {

       var line = getLine(doc, curPos.line);

       if (line.markedSpans) {

         for (var i = 0; i < line.markedSpans.length; ++i) {

           var sp = line.markedSpans[i], m = sp.marker;

           if ((sp.from == null || (m.inclusiveLeft ? sp.from <= curPos.ch : sp.from < curPos.ch)) &&

               (sp.to == null || (m.inclusiveRight ? sp.to >= curPos.ch : sp.to > curPos.ch))) {

             if (mayClear) {

               signal(m, "beforeCursorEnter");

               if (m.explicitlyCleared) {

                 if (!line.markedSpans) break;

                 else {--i; continue;}

               }

             }

             if (!m.atomic) continue;

             var newPos = m.find(dir < 0 ? -1 : 1);

             if (cmp(newPos, curPos) == 0) {

               newPos.ch += dir;

               if (newPos.ch < 0) {

                 if (newPos.line > doc.first) newPos = clipPos(doc, Pos(newPos.line - 1));

                 else newPos = null;

               } else if (newPos.ch > line.text.length) {

                 if (newPos.line < doc.first + doc.size - 1) newPos = Pos(newPos.line + 1, 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(doc, pos, bias, true);

                   // Otherwise, turn off editing until further notice, and return the start of the doc

                   doc.cantEdit = true;

                   return Pos(doc.first, 0);

                 }

                 flipped = true; newPos = pos; dir = -dir;

               }

             }

             curPos = newPos;

             continue search;

           }

         }

       }

       return curPos;

     }

   }

   // SELECTION DRAWING

   // Redraw the selection and/or cursor

   function updateSelection(cm) {

     var display = cm.display, doc = cm.doc;

     var curFragment = document.createDocumentFragment();

     var selFragment = document.createDocumentFragment();

     for (var i = 0; i < doc.sel.ranges.length; i++) {

       var range = doc.sel.ranges[i];

       var collapsed = range.empty();

       if (collapsed || cm.options.showCursorWhenSelecting)

         updateSelectionCursor(cm, range, curFragment);

       if (!collapsed)

         updateSelectionRange(cm, range, selFragment);

     }

     // Move the hidden textarea near the cursor to prevent scrolling artifacts

     if (cm.options.moveInputWithCursor) {

       var headPos = cursorCoords(cm, doc.sel.primary().head, "div");

       var wrapOff = display.wrapper.getBoundingClientRect(), lineOff = display.lineDiv.getBoundingClientRect();

       var top = Math.max(0, Math.min(display.wrapper.clientHeight - 10,

                                      headPos.top + lineOff.top - wrapOff.top));

       var left = Math.max(0, Math.min(display.wrapper.clientWidth - 10,

                                       headPos.left + lineOff.left - wrapOff.left));

       display.inputDiv.style.top = top + "px";

       display.inputDiv.style.left = left + "px";

     }

     removeChildrenAndAdd(display.cursorDiv, curFragment);

     removeChildrenAndAdd(display.selectionDiv, selFragment);

   }

   // Draws a cursor for the given range

   function updateSelectionCursor(cm, range, output) {

     var pos = cursorCoords(cm, range.head, "div");

     var cursor = output.appendChild(elt("div", "\u00a0", "CodeMirror-cursor"));

     cursor.style.left = pos.left + "px";

     cursor.style.top = pos.top + "px";

     cursor.style.height = Math.max(0, pos.bottom - pos.top) * cm.options.cursorHeight + "px";

     if (pos.other) {

       // Secondary cursor, shown when on a 'jump' in bi-directional text

       var otherCursor = output.appendChild(elt("div", "\u00a0", "CodeMirror-cursor CodeMirror-secondarycursor"));

       otherCursor.style.display = "";

       otherCursor.style.left = pos.other.left + "px";

       otherCursor.style.top = pos.other.top + "px";

       otherCursor.style.height = (pos.other.bottom - pos.other.top) * .85 + "px";

     }

   }

   // Draws the given range as a highlighted selection

   function updateSelectionRange(cm, range, output) {

     var display = cm.display, doc = cm.doc;

     var fragment = document.createDocumentFragment();

     var padding = paddingH(cm.display), leftSide = padding.left, rightSide = display.lineSpace.offsetWidth - padding.right;

     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 ? rightSide - left : width) +

                                "px; height: " + (bottom - top) + "px"));

     }

     function drawForLine(line, fromArg, toArg) {

       var lineObj = getLine(doc, line);

       var lineLen = lineObj.text.length;

       var start, end;

       function coords(ch, bias) {

         return charCoords(cm, Pos(line, ch), "div", lineObj, bias);

       }

       iterateBidiSections(getOrder(lineObj), fromArg || 0, toArg == null ? lineLen : toArg, function(from, to, dir) {

         var leftPos = coords(from, "left"), rightPos, left, right;

         if (from == to) {

           rightPos = leftPos;

           left = right = leftPos.left;

         } else {

           rightPos = coords(to - 1, "right");

           if (dir == "rtl") { var tmp = leftPos; leftPos = rightPos; rightPos = tmp; }

           left = leftPos.left;

           right = rightPos.right;

         }

         if (fromArg == null && from == 0) left = leftSide;

         if (rightPos.top - leftPos.top > 3) { // Different lines, draw top part

           add(left, leftPos.top, null, leftPos.bottom);

           left = leftSide;

           if (leftPos.bottom < rightPos.top) add(left, leftPos.bottom, null, rightPos.top);

         }

         if (toArg == null && to == lineLen) right = rightSide;

         if (!start || leftPos.top < start.top || leftPos.top == start.top && leftPos.left < start.left)

           start = leftPos;

         if (!end || rightPos.bottom > end.bottom || rightPos.bottom == end.bottom && rightPos.right > end.right)

           end = rightPos;

         if (left < leftSide + 1) left = leftSide;

         add(left, rightPos.top, right - left, rightPos.bottom);

       });

       return {start: start, end: end};

     }

     var sFrom = range.from(), sTo = range.to();

     if (sFrom.line == sTo.line) {

       drawForLine(sFrom.line, sFrom.ch, sTo.ch);

     } else {

       var fromLine = getLine(doc, sFrom.line), toLine = getLine(doc, sTo.line);

       var singleVLine = visualLine(fromLine) == visualLine(toLine);

       var leftEnd = drawForLine(sFrom.line, sFrom.ch, singleVLine ? fromLine.text.length + 1 : null).end;

       var rightStart = drawForLine(sTo.line, singleVLine ? 0 : null, sTo.ch).start;

       if (singleVLine) {

         if (leftEnd.top < rightStart.top - 2) {

           add(leftEnd.right, leftEnd.top, null, leftEnd.bottom);

           add(leftSide, rightStart.top, rightStart.left, rightStart.bottom);

         } else {

           add(leftEnd.right, leftEnd.top, rightStart.left - leftEnd.right, leftEnd.bottom);

         }

       }

       if (leftEnd.bottom < rightStart.top)

         add(leftSide, leftEnd.bottom, null, rightStart.top);

     }

     output.appendChild(fragment);

   }

   // Cursor-blinking

   function restartBlink(cm) {

     if (!cm.state.focused) return;

     var display = cm.display;

     clearInterval(display.blinker);

     var on = true;

     display.cursorDiv.style.visibility = "";

     if (cm.options.cursorBlinkRate > 0)

       display.blinker = setInterval(function() {

         display.cursorDiv.style.visibility = (on = !on) ? "" : "hidden";

       }, cm.options.cursorBlinkRate);

   }

   // HIGHLIGHT WORKER

   function startWorker(cm, time) {

     if (cm.doc.mode.startState && cm.doc.frontier < cm.display.viewTo)

       cm.state.highlight.set(time, bind(highlightWorker, cm));

   }

   function highlightWorker(cm) {

     var doc = cm.doc;

     if (doc.frontier < doc.first) doc.frontier = doc.first;

     if (doc.frontier >= cm.display.viewTo) return;

     var end = +new Date + cm.options.workTime;

     var state = copyState(doc.mode, getStateBefore(cm, doc.frontier));

     runInOp(cm, function() {

     doc.iter(doc.frontier, Math.min(doc.first + doc.size, cm.display.viewTo + 500), function(line) {

       if (doc.frontier >= cm.display.viewFrom) { // Visible

         var oldStyles = line.styles;

         line.styles = highlightLine(cm, line, state, true);

         var ischange = !oldStyles || oldStyles.length != line.styles.length;

         for (var i = 0; !ischange && i < oldStyles.length; ++i) ischange = oldStyles[i] != line.styles[i];

         if (ischange) regLineChange(cm, doc.frontier, "text");

         line.stateAfter = copyState(doc.mode, state);

       } else {

         processLine(cm, line.text, state);

         line.stateAfter = doc.frontier % 5 == 0 ? copyState(doc.mode, state) : null;

       }

       ++doc.frontier;

       if (+new Date > end) {

         startWorker(cm, cm.options.workDelay);

         return true;

       }

     });

     });

   }

   // Finds the line to start with when starting a parse. Tries to

   // find a line with a stateAfter, so that it can start with a

   // valid state. If that fails, it returns the line with the

   // smallest indentation, which tends to need the least context to

   // parse correctly.

   function findStartLine(cm, n, precise) {

     var minindent, minline, doc = cm.doc;

     var lim = precise ? -1 : n - (cm.doc.mode.innerMode ? 1000 : 100);

     for (var search = n; search > lim; --search) {

       if (search <= doc.first) return doc.first;

       var line = getLine(doc, search - 1);

       if (line.stateAfter && (!precise || search <= doc.frontier)) 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, precise) {

     var doc = cm.doc, display = cm.display;

     if (!doc.mode.startState) return true;

     var pos = findStartLine(cm, n, precise), state = pos > doc.first && getLine(doc, pos-1).stateAfter;

     if (!state) state = startState(doc.mode);

     else state = copyState(doc.mode, state);

     doc.iter(pos, n, function(line) {

       processLine(cm, line.text, state);

       var save = pos == n - 1 || pos % 5 == 0 || pos >= display.viewFrom && pos < display.viewTo;

       line.stateAfter = save ? copyState(doc.mode, state) : null;

       ++pos;

     });

     if (precise) doc.frontier = pos;

     return state;

   }

   // POSITION MEASUREMENT

   function paddingTop(display) {return display.lineSpace.offsetTop;}

   function paddingVert(display) {return display.mover.offsetHeight - display.lineSpace.offsetHeight;}

   function paddingH(display) {

     if (display.cachedPaddingH) return display.cachedPaddingH;

     var e = removeChildrenAndAdd(display.measure, elt("pre", "x"));

     var style = window.getComputedStyle ? window.getComputedStyle(e) : e.currentStyle;

     return display.cachedPaddingH = {left: parseInt(style.paddingLeft),

                                      right: parseInt(style.paddingRight)};

   }

   // Ensure the lineView.wrapping.heights array is populated. This is

   // an array of bottom offsets for the lines that make up a drawn

   // line. When lineWrapping is on, there might be more than one

   // height.

   function ensureLineHeights(cm, lineView, rect) {

     var wrapping = cm.options.lineWrapping;

     var curWidth = wrapping && cm.display.scroller.clientWidth;

     if (!lineView.measure.heights || wrapping && lineView.measure.width != curWidth) {

       var heights = lineView.measure.heights = [];

       if (wrapping) {

         lineView.measure.width = curWidth;

         var rects = lineView.text.firstChild.getClientRects();

         for (var i = 0; i < rects.length - 1; i++) {

           var cur = rects[i], next = rects[i + 1];

           if (Math.abs(cur.bottom - next.bottom) > 2)

             heights.push((cur.bottom + next.top) / 2 - rect.top);

         }

       }

       heights.push(rect.bottom - rect.top);

     }

   }

   // Find a line map (mapping character offsets to text nodes) and a

   // measurement cache for the given line number. (A line view might

   // contain multiple lines when collapsed ranges are present.)

   function mapFromLineView(lineView, line, lineN) {

     if (lineView.line == line)

       return {map: lineView.measure.map, cache: lineView.measure.cache};

     for (var i = 0; i < lineView.rest.length; i++)

       if (lineView.rest[i] == line)

         return {map: lineView.measure.maps[i], cache: lineView.measure.caches[i]};

     for (var i = 0; i < lineView.rest.length; i++)

       if (lineNo(lineView.rest[i]) > lineN)

         return {map: lineView.measure.maps[i], cache: lineView.measure.caches[i], before: true};

   }

   // Render a line into the hidden node display.externalMeasured. Used

   // when measurement is needed for a line that's not in the viewport.

   function updateExternalMeasurement(cm, line) {

     line = visualLine(line);

     var lineN = lineNo(line);

     var view = cm.display.externalMeasured = new LineView(cm.doc, line, lineN);

     view.lineN = lineN;

     var built = view.built = buildLineContent(cm, view);

     view.text = built.pre;

     removeChildrenAndAdd(cm.display.lineMeasure, built.pre);

     return view;

   }

   // Get a {top, bottom, left, right} box (in line-local coordinates)

   // for a given character.

   function measureChar(cm, line, ch, bias) {

     return measureCharPrepared(cm, prepareMeasureForLine(cm, line), ch, bias);

   }

   // Find a line view that corresponds to the given line number.

   function findViewForLine(cm, lineN) {

     if (lineN >= cm.display.viewFrom && lineN < cm.display.viewTo)

       return cm.display.view[findViewIndex(cm, lineN)];

     var ext = cm.display.externalMeasured;

     if (ext && lineN >= ext.lineN && lineN < ext.lineN + ext.size)

       return ext;

   }

   // Measurement can be split in two steps, the set-up work that

   // applies to the whole line, and the measurement of the actual

   // character. Functions like coordsChar, that need to do a lot of

   // measurements in a row, can thus ensure that the set-up work is

   // only done once.

   function prepareMeasureForLine(cm, line) {

     var lineN = lineNo(line);

     var view = findViewForLine(cm, lineN);

     if (view && !view.text)

       view = null;

     else if (view && view.changes)

       updateLineForChanges(cm, view, lineN, getDimensions(cm));

     if (!view)

       view = updateExternalMeasurement(cm, line);

     var info = mapFromLineView(view, line, lineN);

     return {

       line: line, view: view, rect: null,

       map: info.map, cache: info.cache, before: info.before,

       hasHeights: false

     };

   }

   // Given a prepared measurement object, measures the position of an

   // actual character (or fetches it from the cache).

   function measureCharPrepared(cm, prepared, ch, bias) {

     if (prepared.before) ch = -1;

     var key = ch + (bias || ""), found;

     if (prepared.cache.hasOwnProperty(key)) {

       found = prepared.cache[key];

     } else {

       if (!prepared.rect)

         prepared.rect = prepared.view.text.getBoundingClientRect();

       if (!prepared.hasHeights) {

         ensureLineHeights(cm, prepared.view, prepared.rect);

         prepared.hasHeights = true;

       }

       found = measureCharInner(cm, prepared, ch, bias);

       if (!found.bogus) prepared.cache[key] = found;

     }

     return {left: found.left, right: found.right, top: found.top, bottom: found.bottom};

   }

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

   function measureCharInner(cm, prepared, ch, bias) {

     var map = prepared.map;

     var node, start, end, collapse;

     // First, search the line map for the text node corresponding to,

     // or closest to, the target character.

     for (var i = 0; i < map.length; i += 3) {

       var mStart = map[i], mEnd = map[i + 1];

       if (ch < mStart) {

         start = 0; end = 1;

         collapse = "left";

       } else if (ch < mEnd) {

         start = ch - mStart;

         end = start + 1;

       } else if (i == map.length - 3 || ch == mEnd && map[i + 3] > ch) {

         end = mEnd - mStart;

         start = end - 1;

         if (ch >= mEnd) collapse = "right";

       }

       if (start != null) {

         node = map[i + 2];

         if (mStart == mEnd && bias == (node.insertLeft ? "left" : "right"))

           collapse = bias;

         if (bias == "left" && start == 0)

           while (i && map[i - 2] == map[i - 3] && map[i - 1].insertLeft) {

             node = map[(i -= 3) + 2];

             collapse = "left";

           }

         if (bias == "right" && start == mEnd - mStart)

           while (i < map.length - 3 && map[i + 3] == map[i + 4] && !map[i + 5].insertLeft) {

             node = map[(i += 3) + 2];

             collapse = "right";

           }

         break;

       }

     }

     var rect;

     if (node.nodeType == 3) { // If it is a text node, use a range to retrieve the coordinates.

       while (start && isExtendingChar(prepared.line.text.charAt(mStart + start))) --start;

       while (mStart + end < mEnd && isExtendingChar(prepared.line.text.charAt(mStart + end))) ++end;

       if (ie_upto8 && start == 0 && end == mEnd - mStart) {

         rect = node.parentNode.getBoundingClientRect();

       } else if (ie && cm.options.lineWrapping) {

         var rects = range(node, start, end).getClientRects();

         if (rects.length)

           rect = rects[bias == "right" ? rects.length - 1 : 0];

         else

           rect = nullRect;

       } else {

         rect = range(node, start, end).getBoundingClientRect();

       }

     } else { // If it is a widget, simply get the box for the whole widget.

       if (start > 0) collapse = bias = "right";

       var rects;

       if (cm.options.lineWrapping && (rects = node.getClientRects()).length > 1)

         rect = rects[bias == "right" ? rects.length - 1 : 0];

       else

         rect = node.getBoundingClientRect();

     }

     if (ie_upto8 && !start && (!rect || !rect.left && !rect.right)) {

       var rSpan = node.parentNode.getClientRects()[0];

       if (rSpan)

         rect = {left: rSpan.left, right: rSpan.left + charWidth(cm.display), top: rSpan.top, bottom: rSpan.bottom};

       else

         rect = nullRect;

     }

     var top, bot = (rect.bottom + rect.top) / 2 - prepared.rect.top;

     var heights = prepared.view.measure.heights;

     for (var i = 0; i < heights.length - 1; i++)

       if (bot < heights[i]) break;

     top = i ? heights[i - 1] : 0; bot = heights[i];

     var result = {left: (collapse == "right" ? rect.right : rect.left) - prepared.rect.left,

                   right: (collapse == "left" ? rect.left : rect.right) - prepared.rect.left,

                   top: top, bottom: bot};

     if (!rect.left && !rect.right) result.bogus = true;

     return result;

   }

   function clearLineMeasurementCacheFor(lineView) {

     if (lineView.measure) {

       lineView.measure.cache = {};

       lineView.measure.heights = null;

       if (lineView.rest) for (var i = 0; i < lineView.rest.length; i++)

         lineView.measure.caches[i] = {};

     }

   }

   function clearLineMeasurementCache(cm) {

     cm.display.externalMeasure = null;

     removeChildren(cm.display.lineMeasure);

     for (var i = 0; i < cm.display.view.length; i++)

       clearLineMeasurementCacheFor(cm.display.view[i]);

   }

   function clearCaches(cm) {

     clearLineMeasurementCache(cm);

     cm.display.cachedCharWidth = cm.display.cachedTextHeight = cm.display.cachedPaddingH = null;

     if (!cm.options.lineWrapping) cm.display.maxLineChanged = true;

     cm.display.lineNumChars = null;

   }

   function pageScrollX() { return window.pageXOffset || (document.documentElement || document.body).scrollLeft; }

   function pageScrollY() { return window.pageYOffset || (document.documentElement || document.body).scrollTop; }

   // Converts a {top, bottom, left, right} box from line-local

   // coordinates into another coordinate system. Context may be one of

   // "line", "div" (display.lineDiv), "local"/null (editor), 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 = widgetHeight(lineObj.widgets[i]);

       rect.top += size; rect.bottom += size;

     }

     if (context == "line") return rect;

     if (!context) context = "local";

     var yOff = heightAtLine(lineObj);

     if (context == "local") yOff += paddingTop(cm.display);

     else yOff -= cm.display.viewOffset;

     if (context == "page" || context == "window") {

       var lOff = cm.display.lineSpace.getBoundingClientRect();

       yOff += lOff.top + (context == "window" ? 0 : pageScrollY());

       var xOff = lOff.left + (context == "window" ? 0 : pageScrollX());

       rect.left += xOff; rect.right += xOff;

     }

     rect.top += yOff; rect.bottom += yOff;

     return rect;

   }

   // Coverts a box from "div" coords to another coordinate system.

   // Context may be "window", "page", "div", or "local"/null.

   function fromCoordSystem(cm, coords, context) {

     if (context == "div") return coords;

     var left = coords.left, top = coords.top;

     // First move into "page" coordinate system

     if (context == "page") {

       left -= pageScrollX();

       top -= pageScrollY();

     } else if (context == "local" || !context) {

       var localBox = cm.display.sizer.getBoundingClientRect();

       left += localBox.left;

       top += localBox.top;

     }

     var lineSpaceBox = cm.display.lineSpace.getBoundingClientRect();

     return {left: left - lineSpaceBox.left, top: top - lineSpaceBox.top};

   }

   function charCoords(cm, pos, context, lineObj, bias) {

     if (!lineObj) lineObj = getLine(cm.doc, pos.line);

     return intoCoordSystem(cm, lineObj, measureChar(cm, lineObj, pos.ch, bias), context);

   }

   // Returns a box for a given cursor position, which may have an

   // 'other' property containing the position of the secondary cursor

   // on a bidi boundary.

   function cursorCoords(cm, pos, context, lineObj, preparedMeasure) {

     lineObj = lineObj || getLine(cm.doc, pos.line);

     if (!preparedMeasure) preparedMeasure = prepareMeasureForLine(cm, lineObj);

     function get(ch, right) {

       var m = measureCharPrepared(cm, preparedMeasure, ch, right ? "right" : "left");

       if (right) m.left = m.right; else m.right = m.left;

       return intoCoordSystem(cm, lineObj, m, context);

     }

     function getBidi(ch, partPos) {

       var part = order[partPos], right = part.level % 2;

       if (ch == bidiLeft(part) && partPos && part.level < order[partPos - 1].level) {

         part = order[--partPos];

         ch = bidiRight(part) - (part.level % 2 ? 0 : 1);

         right = true;

       } else if (ch == bidiRight(part) && partPos < order.length - 1 && part.level < order[partPos + 1].level) {

         part = order[++partPos];

         ch = bidiLeft(part) - part.level % 2;

         right = false;

       }

       if (right && ch == part.to && ch > part.from) return get(ch - 1);

       return get(ch, right);

     }

     var order = getOrder(lineObj), ch = pos.ch;

     if (!order) return get(ch);

     var partPos = getBidiPartAt(order, ch);

     var val = getBidi(ch, partPos);

     if (bidiOther != null) val.other = getBidi(ch, bidiOther);

     return val;

   }

   // Used to cheaply estimate the coordinates for a position. Used for

   // intermediate scroll updates.

   function estimateCoords(cm, pos) {

     var left = 0, pos = clipPos(cm.doc, pos);

     if (!cm.options.lineWrapping) left = charWidth(cm.display) * pos.ch;

     var lineObj = getLine(cm.doc, pos.line);

     var top = heightAtLine(lineObj) + paddingTop(cm.display);

     return {left: left, right: left, top: top, bottom: top + lineObj.height};

   }

   // Positions returned by coordsChar contain some extra information.

   // xRel is the relative x position of the input coordinates compared

   // to the found position (so xRel > 0 means the coordinates are to

   // the right of the character position, for example). When outside

   // is true, that means the coordinates lie outside the line's

   // vertical range.

   function PosWithInfo(line, ch, outside, xRel) {

     var pos = Pos(line, ch);

     pos.xRel = xRel;

     if (outside) pos.outside = true;

     return pos;

   }

   // Compute the character position closest to the given coordinates.

   // Input must be lineSpace-local ("div" coordinate system).

   function coordsChar(cm, x, y) {

     var doc = cm.doc;

     y += cm.display.viewOffset;

     if (y < 0) return PosWithInfo(doc.first, 0, true, -1);

     var lineN = lineAtHeight(doc, y), last = doc.first + doc.size - 1;

     if (lineN > last)

       return PosWithInfo(doc.first + doc.size - 1, getLine(doc, last).text.length, true, 1);

     if (x < 0) x = 0;

     var lineObj = getLine(doc, lineN);

     for (;;) {

       var found = coordsCharInner(cm, lineObj, lineN, x, y);

       var merged = collapsedSpanAtEnd(lineObj);

       var mergedPos = merged && merged.find(0, true);

       if (merged && (found.ch > mergedPos.from.ch || found.ch == mergedPos.from.ch && found.xRel > 0))

         lineN = lineNo(lineObj = mergedPos.to.line);

       else

         return found;

     }

   }

   function coordsCharInner(cm, lineObj, lineNo, x, y) {

     var innerOff = y - heightAtLine(lineObj);

     var wrongLine = false, adjust = 2 * cm.display.wrapper.clientWidth;

     var preparedMeasure = prepareMeasureForLine(cm, lineObj);

     function getX(ch) {

       var sp = cursorCoords(cm, Pos(lineNo, ch), "line", lineObj, preparedMeasure);

       wrongLine = true;

       if (innerOff > sp.bottom) return sp.left - adjust;

       else if (innerOff < sp.top) return sp.left + adjust;

       else wrongLine = false;

       return sp.left;

     }

     var bidi = getOrder(lineObj), dist = lineObj.text.length;

     var from = lineLeft(lineObj), to = lineRight(lineObj);

     var fromX = getX(from), fromOutside = wrongLine, toX = getX(to), toOutside = wrongLine;

     if (x > toX) return PosWithInfo(lineNo, to, toOutside, 1);

     // Do a binary search between these bounds.

     for (;;) {

       if (bidi ? to == from || to == moveVisually(lineObj, from, 1) : to - from <= 1) {

         var ch = x < fromX || x - fromX <= toX - x ? from : to;

         var xDiff = x - (ch == from ? fromX : toX);

         while (isExtendingChar(lineObj.text.charAt(ch))) ++ch;

         var pos = PosWithInfo(lineNo, ch, ch == from ? fromOutside : toOutside,

                               xDiff < -1 ? -1 : xDiff > 1 ? 1 : 0);

         return pos;

       }

       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 (toOutside = wrongLine) toX += 1000; dist = step;}

       else {from = middle; fromX = middleX; fromOutside = wrongLine; dist -= step;}

     }

   }

   var measureText;

   // Compute the default text height.

   function textHeight(display) {

     if (display.cachedTextHeight != null) return display.cachedTextHeight;

     if (measureText == null) {

       measureText = elt("pre");

       // Measure a bunch of lines, for browsers that compute

       // fractional heights.

       for (var i = 0; i < 49; ++i) {

         measureText.appendChild(document.createTextNode("x"));

         measureText.appendChild(elt("br"));

       }

       measureText.appendChild(document.createTextNode("x"));

     }

     removeChildrenAndAdd(display.measure, measureText);

     var height = measureText.offsetHeight / 50;

     if (height > 3) display.cachedTextHeight = height;

     removeChildren(display.measure);

     return height || 1;

   }

   // Compute the default character width.

   function charWidth(display) {

     if (display.cachedCharWidth != null) return display.cachedCharWidth;

     var anchor = elt("span", "xxxxxxxxxx");

     var pre = elt("pre", [anchor]);

     removeChildrenAndAdd(display.measure, pre);

     var rect = anchor.getBoundingClientRect(), width = (rect.right - rect.left) / 10;

     if (width > 2) display.cachedCharWidth = width;

     return width || 10;

   }

   // OPERATIONS

   // Operations are used to wrap a series of changes to the editor

   // state in such a way that each change won't have to update the

   // cursor and display (which would be awkward, slow, and

   // error-prone). Instead, display updates are batched and then all

   // combined and executed at once.

   var nextOpId = 0;

   // Start a new operation.

   function startOperation(cm) {

     cm.curOp = {

       viewChanged: false,      // Flag that indicates that lines might need to be redrawn

       startHeight: cm.doc.height, // Used to detect need to update scrollbar

       forceUpdate: false,      // Used to force a redraw

       updateInput: null,       // Whether to reset the input textarea

       typing: false,           // Whether this reset should be careful to leave existing text (for compositing)

       changeObjs: null,        // Accumulated changes, for firing change events

       cursorActivity: false,   // Whether to fire a cursorActivity event

       selectionChanged: false, // Whether the selection needs to be redrawn

       updateMaxLine: false,    // Set when the widest line needs to be determined anew

       scrollLeft: null, scrollTop: null, // Intermediate scroll position, not pushed to DOM yet

       scrollToPos: null,       // Used to scroll to a specific position

       id: ++nextOpId           // Unique ID

     };

     if (!delayedCallbackDepth++) delayedCallbacks = [];

   }

   // Finish an operation, updating the display and signalling delayed events

   function endOperation(cm) {

     var op = cm.curOp, doc = cm.doc, display = cm.display;

     cm.curOp = null;

     if (op.updateMaxLine) findMaxLine(cm);

     // If it looks like an update might be needed, call updateDisplay

     if (op.viewChanged || op.forceUpdate || op.scrollTop != null ||

         op.scrollToPos && (op.scrollToPos.from.line < display.viewFrom ||

                            op.scrollToPos.to.line >= display.viewTo) ||

         display.maxLineChanged && cm.options.lineWrapping) {

       var updated = updateDisplay(cm, {top: op.scrollTop, ensure: op.scrollToPos}, op.forceUpdate);

       if (cm.display.scroller.offsetHeight) cm.doc.scrollTop = cm.display.scroller.scrollTop;

     }

     // If no update was run, but the selection changed, redraw that.

     if (!updated && op.selectionChanged) updateSelection(cm);

     if (!updated && op.startHeight != cm.doc.height) updateScrollbars(cm);

     // Propagate the scroll position to the actual DOM scroller

     if (op.scrollTop != null && display.scroller.scrollTop != op.scrollTop) {

       var top = Math.max(0, Math.min(display.scroller.scrollHeight - display.scroller.clientHeight, op.scrollTop));

       display.scroller.scrollTop = display.scrollbarV.scrollTop = doc.scrollTop = top;

     }

     if (op.scrollLeft != null && display.scroller.scrollLeft != op.scrollLeft) {

       var left = Math.max(0, Math.min(display.scroller.scrollWidth - display.scroller.clientWidth, op.scrollLeft));

       display.scroller.scrollLeft = display.scrollbarH.scrollLeft = doc.scrollLeft = left;

       alignHorizontally(cm);

     }

     // If we need to scroll a specific position into view, do so.

     if (op.scrollToPos) {

       var coords = scrollPosIntoView(cm, clipPos(cm.doc, op.scrollToPos.from),

                                      clipPos(cm.doc, op.scrollToPos.to), op.scrollToPos.margin);

       if (op.scrollToPos.isCursor && cm.state.focused) maybeScrollWindow(cm, coords);

     }

     if (op.selectionChanged) restartBlink(cm);

     if (cm.state.focused && op.updateInput)

       resetInput(cm, op.typing);

     // Fire events for markers that are hidden/unidden by editing or

     // undoing

     var hidden = op.maybeHiddenMarkers, unhidden = op.maybeUnhiddenMarkers;

     if (hidden) for (var i = 0; i < hidden.length; ++i)

       if (!hidden[i].lines.length) signal(hidden[i], "hide");

     if (unhidden) for (var i = 0; i < unhidden.length; ++i)

       if (unhidden[i].lines.length) signal(unhidden[i], "unhide");

     var delayed;

     if (!--delayedCallbackDepth) {

       delayed = delayedCallbacks;

       delayedCallbacks = null;

     }

     // Fire change events, and delayed event handlers

     if (op.changeObjs) {

       for (var i = 0; i < op.changeObjs.length; i++)

         signal(cm, "change", cm, op.changeObjs[i]);

       signal(cm, "changes", cm, op.changeObjs);

     }

     if (op.cursorActivity) signal(cm, "cursorActivity", cm);

     if (delayed) for (var i = 0; i < delayed.length; ++i) delayed[i]();

   }

   // Run the given function in an operation

   function runInOp(cm, f) {

     if (cm.curOp) return f();

     startOperation(cm);

     try { return f(); }

     finally { endOperation(cm); }

   }

   // Wraps a function in an operation. Returns the wrapped function.

   function operation(cm, f) {

     return function() {

       if (cm.curOp) return f.apply(cm, arguments);

       startOperation(cm);

       try { return f.apply(cm, arguments); }

       finally { endOperation(cm); }

     };

   }

   // Used to add methods to editor and doc instances, wrapping them in

   // operations.

   function methodOp(f) {

     return function() {

       if (this.curOp) return f.apply(this, arguments);

       startOperation(this);

       try { return f.apply(this, arguments); }

       finally { endOperation(this); }

     };

   }

   function docMethodOp(f) {

     return function() {

       var cm = this.cm;

       if (!cm || cm.curOp) return f.apply(this, arguments);

       startOperation(cm);

       try { return f.apply(this, arguments); }

       finally { endOperation(cm); }

     };

   }

   // VIEW TRACKING

   // These objects are used to represent the visible (currently drawn)

   // part of the document. A LineView may correspond to multiple

   // logical lines, if those are connected by collapsed ranges.

   function LineView(doc, line, lineN) {

     // The starting line

     this.line = line;

     // Continuing lines, if any

     this.rest = visualLineContinued(line);

     // Number of logical lines in this visual line

     this.size = this.rest ? lineNo(lst(this.rest)) - lineN + 1 : 1;

     this.node = this.text = null;

     this.hidden = lineIsHidden(doc, line);

   }

   // Create a range of LineView objects for the given lines.

   function buildViewArray(cm, from, to) {

     var array = [], nextPos;

     for (var pos = from; pos < to; pos = nextPos) {

       var view = new LineView(cm.doc, getLine(cm.doc, pos), pos);

       nextPos = pos + view.size;

       array.push(view);

     }

     return array;

   }

   // Updates the display.view data structure for a given change to the

   // document. From and to are in pre-change coordinates. Lendiff is

   // the amount of lines added or subtracted by the change. This is

   // used for changes that span multiple lines, or change the way

   // lines are divided into visual lines. regLineChange (below)

   // registers single-line changes.

   function regChange(cm, from, to, lendiff) {

     if (from == null) from = cm.doc.first;

     if (to == null) to = cm.doc.first + cm.doc.size;

     if (!lendiff) lendiff = 0;

     var display = cm.display;

     if (lendiff && to < display.viewTo &&

         (display.updateLineNumbers == null || display.updateLineNumbers > from))

       display.updateLineNumbers = from;

     cm.curOp.viewChanged = true;

     if (from >= display.viewTo) { // Change after

       if (sawCollapsedSpans && visualLineNo(cm.doc, from) < display.viewTo)

         resetView(cm);

     } else if (to <= display.viewFrom) { // Change before

       if (sawCollapsedSpans && visualLineEndNo(cm.doc, to + lendiff) > display.viewFrom) {

         resetView(cm);

       } else {

         display.viewFrom += lendiff;

         display.viewTo += lendiff;

       }

     } else if (from <= display.viewFrom && to >= display.viewTo) { // Full overlap

       resetView(cm);

     } else if (from <= display.viewFrom) { // Top overlap

       var cut = viewCuttingPoint(cm, to, to + lendiff, 1);

       if (cut) {

         display.view = display.view.slice(cut.index);

         display.viewFrom = cut.lineN;

         display.viewTo += lendiff;

       } else {

         resetView(cm);

       }

     } else if (to >= display.viewTo) { // Bottom overlap

       var cut = viewCuttingPoint(cm, from, from, -1);

       if (cut) {

         display.view = display.view.slice(0, cut.index);

         display.viewTo = cut.lineN;

       } else {

         resetView(cm);

       }

     } else { // Gap in the middle

       var cutTop = viewCuttingPoint(cm, from, from, -1);

       var cutBot = viewCuttingPoint(cm, to, to + lendiff, 1);

       if (cutTop && cutBot) {

         display.view = display.view.slice(0, cutTop.index)

           .concat(buildViewArray(cm, cutTop.lineN, cutBot.lineN))

           .concat(display.view.slice(cutBot.index));

         display.viewTo += lendiff;

       } else {

         resetView(cm);

       }

     }

     var ext = display.externalMeasured;

     if (ext) {

       if (to < ext.lineN)

         ext.lineN += lendiff;

       else if (from < ext.lineN + ext.size)

         display.externalMeasured = null;

     }

   }

   // Register a change to a single line. Type must be one of "text",

   // "gutter", "class", "widget"

   function regLineChange(cm, line, type) {

     cm.curOp.viewChanged = true;

     var display = cm.display, ext = cm.display.externalMeasured;

     if (ext && line >= ext.lineN && line < ext.lineN + ext.size)

       display.externalMeasured = null;

     if (line < display.viewFrom || line >= display.viewTo) return;

     var lineView = display.view[findViewIndex(cm, line)];

     if (lineView.node == null) return;

     var arr = lineView.changes || (lineView.changes = []);

     if (indexOf(arr, type) == -1) arr.push(type);

   }

   // Clear the view.

   function resetView(cm) {

     cm.display.viewFrom = cm.display.viewTo = cm.doc.first;

     cm.display.view = [];

     cm.display.viewOffset = 0;

   }

   // Find the view element corresponding to a given line. Return null

   // when the line isn't visible.

   function findViewIndex(cm, n) {

     if (n >= cm.display.viewTo) return null;

     n -= cm.display.viewFrom;

     if (n < 0) return null;

     var view = cm.display.view;

     for (var i = 0; i < view.length; i++) {

       n -= view[i].size;

       if (n < 0) return i;

     }

   }

   function viewCuttingPoint(cm, oldN, newN, dir) {

     var index = findViewIndex(cm, oldN), diff, view = cm.display.view;

     if (!sawCollapsedSpans) return {index: index, lineN: newN};

     for (var i = 0, n = cm.display.viewFrom; i < index; i++)

       n += view[i].size;

     if (n != oldN) {

       if (dir > 0) {

         if (index == view.length - 1) return null;

         diff = (n + view[index].size) - oldN;

         index++;

       } else {

         diff = n - oldN;

       }

       oldN += diff; newN += diff;

     }

     while (visualLineNo(cm.doc, newN) != newN) {

       if (index == (dir < 0 ? 0 : view.length - 1)) return null;

       newN += dir * view[index - (dir < 0 ? 1 : 0)].size;

       index += dir;

     }

     return {index: index, lineN: newN};

   }

   // Force the view to cover a given range, adding empty view element

   // or clipping off existing ones as needed.

   function adjustView(cm, from, to) {

     var display = cm.display, view = display.view;

     if (view.length == 0 || from >= display.viewTo || to <= display.viewFrom) {

       display.view = buildViewArray(cm, from, to);

       display.viewFrom = from;

     } else {

       if (display.viewFrom > from)

         display.view = buildViewArray(cm, from, display.viewFrom).concat(display.view);

       else if (display.viewFrom < from)

         display.view = display.view.slice(findViewIndex(cm, from));

       display.viewFrom = from;

       if (display.viewTo < to)

         display.view = display.view.concat(buildViewArray(cm, display.viewTo, to));

       else if (display.viewTo > to)

         display.view = display.view.slice(0, findViewIndex(cm, to));

     }

     display.viewTo = to;

   }

   // Count the number of lines in the view whose DOM representation is

   // out of date (or nonexistent).

   function countDirtyView(cm) {

     var view = cm.display.view, dirty = 0;

     for (var i = 0; i < view.length; i++) {

       var lineView = view[i];

       if (!lineView.hidden && (!lineView.node || lineView.changes)) ++dirty;

     }

     return dirty;

   }

   // INPUT HANDLING

   // Poll for input changes, using the normal rate of polling. This

   // runs as long as the editor is focused.

   function slowPoll(cm) {

     if (cm.display.pollingFast) return;

     cm.display.poll.set(cm.options.pollInterval, function() {

       readInput(cm);

       if (cm.state.focused) slowPoll(cm);

     });

   }

   // When an event has just come in that is likely to add or change

   // something in the input textarea, we poll faster, to ensure that

   // the change appears on the screen quickly.

   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);

   }

   // Read input from the textarea, and update the document to match.

   // When something is selected, it is present in the textarea, and

   // selected (unless it is huge, in which case a placeholder is

   // used). When nothing is selected, the cursor sits after previously

   // seen text (can be empty), which is stored in prevInput (we must

   // not reset the textarea when typing, because that breaks IME).

   function readInput(cm) {

     var input = cm.display.input, prevInput = cm.display.prevInput, doc = cm.doc;

     // Since this is called a *lot*, try to bail out as cheaply as

     // possible when it is clear that nothing happened. hasSelection

     // will be the case when there is a lot of text in the textarea,

     // in which case reading its value would be expensive.

     if (!cm.state.focused || hasSelection(input) || isReadOnly(cm) || cm.options.disableInput) return false;

     var text = input.value;

     // If nothing changed, bail.

     if (text == prevInput && !cm.somethingSelected()) return false;

     // Work around nonsensical selection resetting in IE9/10

     if (ie && !ie_upto8 && cm.display.inputHasSelection === text) {

       resetInput(cm);

       return false;

     }

     var withOp = !cm.curOp;

     if (withOp) startOperation(cm);

     cm.display.shift = false;

     // Find the part of the input that is actually new

     var same = 0, l = Math.min(prevInput.length, text.length);

     while (same < l && prevInput.charCodeAt(same) == text.charCodeAt(same)) ++same;

     var inserted = text.slice(same), textLines = splitLines(inserted);

     // When pasing N lines into N selections, insert one line per selection

     var multiPaste = cm.state.pasteIncoming && textLines.length > 1 && doc.sel.ranges.length == textLines.length;

     // Normal behavior is to insert the new text into every selection

     for (var i = doc.sel.ranges.length - 1; i >= 0; i--) {

       var range = doc.sel.ranges[i];

       var from = range.from(), to = range.to();

       // Handle deletion

       if (same < prevInput.length)

         from = Pos(from.line, from.ch - (prevInput.length - same));

       // Handle overwrite

       else if (cm.state.overwrite && range.empty() && !cm.state.pasteIncoming)

         to = Pos(to.line, Math.min(getLine(doc, to.line).text.length, to.ch + lst(textLines).length));

       var updateInput = cm.curOp.updateInput;

       var changeEvent = {from: from, to: to, text: multiPaste ? [textLines[i]] : textLines,

                          origin: cm.state.pasteIncoming ? "paste" : cm.state.cutIncoming ? "cut" : "+input"};

       makeChange(cm.doc, changeEvent);

       signalLater(cm, "inputRead", cm, changeEvent);

       // When an 'electric' character is inserted, immediately trigger a reindent

       if (inserted && !cm.state.pasteIncoming && cm.options.electricChars &&

           cm.options.smartIndent && range.head.ch < 100 &&

           (!i || doc.sel.ranges[i - 1].head.line != range.head.line)) {

         var electric = cm.getModeAt(range.head).electricChars;

         if (electric) for (var j = 0; j < electric.length; j++)

           if (inserted.indexOf(electric.charAt(j)) > -1) {

             indentLine(cm, range.head.line, "smart");

             break;

           }

       }

     }

     ensureCursorVisible(cm);

     cm.curOp.updateInput = updateInput;

     cm.curOp.typing = true;

     // Don't leave long text in the textarea, since it makes further polling slow

     if (text.length > 1000 || text.indexOf("\n") > -1) input.value = cm.display.prevInput = "";

     else cm.display.prevInput = text;

     if (withOp) endOperation(cm);

     cm.state.pasteIncoming = cm.state.cutIncoming = false;

     return true;

   }

   // Reset the input to correspond to the selection (or to be empty,

   // when not typing and nothing is selected)

   function resetInput(cm, typing) {

     var minimal, selected, doc = cm.doc;

     if (cm.somethingSelected()) {

       cm.display.prevInput = "";

       var range = doc.sel.primary();

       minimal = hasCopyEvent &&

         (range.to().line - range.from().line > 100 || (selected = cm.getSelection()).length > 1000);

       var content = minimal ? "-" : selected || cm.getSelection();

       cm.display.input.value = content;

       if (cm.state.focused) selectInput(cm.display.input);

       if (ie && !ie_upto8) cm.display.inputHasSelection = content;

     } else if (!typing) {

       cm.display.prevInput = cm.display.input.value = "";

       if (ie && !ie_upto8) cm.display.inputHasSelection = null;

     }

     cm.display.inaccurateSelection = minimal;

   }

   function focusInput(cm) {

     if (cm.options.readOnly != "nocursor" && (!mobile || activeElt() != cm.display.input))

       cm.display.input.focus();

   }

   function ensureFocus(cm) {

     if (!cm.state.focused) { focusInput(cm); onFocus(cm); }

   }

   function isReadOnly(cm) {

     return cm.options.readOnly || cm.doc.cantEdit;

   }

   // EVENT HANDLERS

   // Attach the necessary event handlers when initializing the editor

   function registerEventHandlers(cm) {

     var d = cm.display;

     on(d.scroller, "mousedown", operation(cm, onMouseDown));

     // Older IE's will not fire a second mousedown for a double click

     if (ie_upto10)

       on(d.scroller, "dblclick", operation(cm, function(e) {

         if (signalDOMEvent(cm, e)) return;

         var pos = posFromMouse(cm, e);

         if (!pos || clickInGutter(cm, e) || eventInWidget(cm.display, e)) return;

         e_preventDefault(e);

         var word = findWordAt(cm.doc, pos);

         extendSelection(cm.doc, word.anchor, word.head);

       }));

     else

       on(d.scroller, "dblclick", function(e) { signalDOMEvent(cm, e) || e_preventDefault(e); });

     // Prevent normal selection in the editor (we handle our own)

     on(d.lineSpace, "selectstart", function(e) {

       if (!eventInWidget(d, e)) e_preventDefault(e);

     });

     // Some browsers fire contextmenu *after* opening the menu, at

     // which point we can't mess with it anymore. Context menu is

     // handled in onMouseDown for these browsers.

     if (!captureRightClick) on(d.scroller, "contextmenu", function(e) {onContextMenu(cm, e);});

     // Sync scrolling between fake scrollbars and real scrollable

     // area, ensure viewport is updated when scrolling.

     on(d.scroller, "scroll", function() {

       if (d.scroller.clientHeight) {

         setScrollTop(cm, d.scroller.scrollTop);

         setScrollLeft(cm, d.scroller.scrollLeft, true);

         signal(cm, "scroll", cm);

       }

     });

     on(d.scrollbarV, "scroll", function() {

       if (d.scroller.clientHeight) setScrollTop(cm, d.scrollbarV.scrollTop);

     });

     on(d.scrollbarH, "scroll", function() {

       if (d.scroller.clientHeight) setScrollLeft(cm, d.scrollbarH.scrollLeft);

     });

     // Listen to wheel events in order to try and update the viewport on time.

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

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

     // Prevent clicks in the scrollbars from killing focus

     function reFocus() { if (cm.state.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; });

     // When the window resizes, we need to refresh active editors.

     var resizeTimer;

     function onResize() {

       if (resizeTimer == null) resizeTimer = setTimeout(function() {

         resizeTimer = null;

         // Might be a text scaling operation, clear size caches.

         d.cachedCharWidth = d.cachedTextHeight = d.cachedPaddingH = knownScrollbarWidth = null;

         cm.setSize();

       }, 100);

     }

     on(window, "resize", onResize);

     // The above handler holds on to the editor and its data

     // structures. Here we poll to unregister it when the editor is no

     // longer in the document, so that it can be garbage-collected.

     function unregister() {

       if (contains(document.body, d.wrapper)) setTimeout(unregister, 5000);

       else off(window, "resize", onResize);

     }

     setTimeout(unregister, 5000);

     on(d.input, "keyup", operation(cm, onKeyUp));

     on(d.input, "input", function() {

       if (ie && !ie_upto8 && cm.display.inputHasSelection) cm.display.inputHasSelection = null;

       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 (!signalDOMEvent(cm, e)) 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(e) {

       if (eventInWidget(d, e)) return;

       cm.state.pasteIncoming = true;

       focusInput(cm);

       fastPoll(cm);

     });

     on(d.input, "paste", function() {

       cm.state.pasteIncoming = true;

       fastPoll(cm);

     });

     function prepareCopy(e) {

       if (d.inaccurateSelection) {

         d.prevInput = "";

         d.inaccurateSelection = false;

         d.input.value = cm.getSelection();

         selectInput(d.input);

       }

       if (e.type == "cut") cm.state.cutIncoming = true;

     }

     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 (activeElt() == d.input) d.input.blur();

       focusInput(cm);

     });

   }

   // MOUSE EVENTS

   // Return true when the given mouse event happened in a widget

   function eventInWidget(display, e) {

     for (var n = e_target(e); n != display.wrapper; n = n.parentNode) {

       if (!n || n.ignoreEvents || n.parentNode == display.sizer && n != display.mover) return true;

     }

   }

   // Given a mouse event, find the corresponding position. If liberal

   // is false, it checks whether a gutter or scrollbar was clicked,

   // and returns null if it was. forRect is used by rectangular

   // selections, and tries to estimate a character position even for

   // coordinates beyond the right of the text.

   function posFromMouse(cm, e, liberal, forRect) {

     var display = cm.display;

     if (!liberal) {

       var target = e_target(e);

       if (target == display.scrollbarH || target == display.scrollbarV ||

           target == display.scrollbarFiller || target == display.gutterFiller) return null;

     }

     var x, y, space = display.lineSpace.getBoundingClientRect();

     // Fails unpredictably on IE[67] when mouse is dragged around quickly.

     try { x = e.clientX - space.left; y = e.clientY - space.top; }

     catch (e) { return null; }

     var coords = coordsChar(cm, x, y), line;

     if (forRect && coords.xRel == 1 && (line = getLine(cm.doc, coords.line).text).length == coords.ch) {

       var colDiff = countColumn(line, line.length, cm.options.tabSize) - line.length;

       coords = Pos(coords.line, Math.round((x - paddingH(cm.display).left) / charWidth(cm.display)) - colDiff);

     }

     return coords;

   }

   // A mouse down can be a single click, double click, triple click,

   // start of selection drag, start of text drag, new cursor

   // (ctrl-click), rectangle drag (alt-drag), or xwin

   // middle-click-paste. Or it might be a click on something we should

   // not interfere with, such as a scrollbar or widget.

   function onMouseDown(e) {

     if (signalDOMEvent(this, e)) return;

     var cm = this, display = cm.display;

     display.shift = e.shiftKey;

     if (eventInWidget(display, e)) {

       if (!webkit) {

         // Briefly turn off draggability, to allow widgets to do

         // normal dragging things.

         display.scroller.draggable = false;

         setTimeout(function(){display.scroller.draggable = true;}, 100);

       }

       return;

     }

     if (clickInGutter(cm, e)) return;

     var start = posFromMouse(cm, e);

     window.focus();

     switch (e_button(e)) {

     case 1:

       if (start)

         leftButtonDown(cm, e, start);

       else if (e_target(e) == display.scroller)

         e_preventDefault(e);

       break;

     case 2:

       if (webkit) cm.state.lastMiddleDown = +new Date;

       if (start) extendSelection(cm.doc, start);

       setTimeout(bind(focusInput, cm), 20);

       e_preventDefault(e);

       break;

     case 3:

       if (captureRightClick) onContextMenu(cm, e);

       break;

     }

   }

   var lastClick, lastDoubleClick;

   function leftButtonDown(cm, e, start) {

     setTimeout(bind(ensureFocus, cm), 0);

     var now = +new Date, type;

     if (lastDoubleClick && lastDoubleClick.time > now - 400 && cmp(lastDoubleClick.pos, start) == 0) {

       type = "triple";

     } else if (lastClick && lastClick.time > now - 400 && cmp(lastClick.pos, start) == 0) {

       type = "double";

       lastDoubleClick = {time: now, pos: start};

     } else {

       type = "single";

       lastClick = {time: now, pos: start};

     }

     var sel = cm.doc.sel, addNew = mac ? e.metaKey : e.ctrlKey;

     if (cm.options.dragDrop && dragAndDrop && !addNew && !isReadOnly(cm) &&

         type == "single" && sel.contains(start) > -1 && sel.somethingSelected())

       leftButtonStartDrag(cm, e, start);

     else

       leftButtonSelect(cm, e, start, type, addNew);

   }

   // Start a text drag. When it ends, see if any dragging actually

   // happen, and treat as a click if it didn't.

   function leftButtonStartDrag(cm, e, start) {

     var display = cm.display;

     var dragEnd = operation(cm, function(e2) {

       if (webkit) display.scroller.draggable = false;

       cm.state.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.doc, start);

         focusInput(cm);

         // Work around unexplainable focus problem in IE9 (#2127)

         if (ie_upto10 && !ie_upto8)

           setTimeout(function() {document.body.focus(); focusInput(cm);}, 20);

       }

     });

     // Let the drag handler handle this.

     if (webkit) display.scroller.draggable = true;

     cm.state.draggingText = dragEnd;

     // IE's approach to draggable

     if (display.scroller.dragDrop) display.scroller.dragDrop();

     on(document, "mouseup", dragEnd);

     on(display.scroller, "drop", dragEnd);

   }

   // Normal selection, as opposed to text dragging.

   function leftButtonSelect(cm, e, start, type, addNew) {

     var display = cm.display, doc = cm.doc;

     e_preventDefault(e);

     var ourRange, ourIndex, startSel = doc.sel;

     if (addNew) {

       ourIndex = doc.sel.contains(start);

       if (ourIndex > -1)

         ourRange = doc.sel.ranges[ourIndex];

       else

         ourRange = new Range(start, start);

     } else {

       ourRange = doc.sel.primary();

     }

     if (e.altKey) {

       type = "rect";

       if (!addNew) ourRange = new Range(start, start);

       start = posFromMouse(cm, e, true, true);

       ourIndex = -1;

     } else if (type == "double") {

       var word = findWordAt(doc, start);

       if (cm.display.shift || doc.extend)

         ourRange = extendRange(doc, ourRange, word.anchor, word.head);

       else

         ourRange = word;

     } else if (type == "triple") {

       var line = new Range(Pos(start.line, 0), clipPos(doc, Pos(start.line + 1, 0)));

       if (cm.display.shift || doc.extend)

         ourRange = extendRange(doc, ourRange, line.anchor, line.head);

       else

         ourRange = line;

     } else {

       ourRange = extendRange(doc, ourRange, start);

     }

     if (!addNew) {

       ourIndex = 0;

       setSelection(doc, new Selection([ourRange], 0), sel_mouse);

     } else if (ourIndex > -1) {

       replaceOneSelection(doc, ourIndex, ourRange, sel_mouse);

     } else {

       ourIndex = doc.sel.ranges.length;

       setSelection(doc, normalizeSelection(doc.sel.ranges.concat([ourRange]), ourIndex),

                    {scroll: false, origin: "*mouse"});

     }

     var lastPos = start;

     function extendTo(pos) {

       if (cmp(lastPos, pos) == 0) return;

       lastPos = pos;

       if (type == "rect") {

         var ranges = [], tabSize = cm.options.tabSize;

         var startCol = countColumn(getLine(doc, start.line).text, start.ch, tabSize);

         var posCol = countColumn(getLine(doc, pos.line).text, pos.ch, tabSize);

         var left = Math.min(startCol, posCol), right = Math.max(startCol, posCol);

         for (var line = Math.min(start.line, pos.line), end = Math.min(cm.lastLine(), Math.max(start.line, pos.line));

              line <= end; line++) {

           var text = getLine(doc, line).text, leftPos = findColumn(text, left, tabSize);

           if (left == right)

             ranges.push(new Range(Pos(line, leftPos), Pos(line, leftPos)));

           else if (text.length > leftPos)

             ranges.push(new Range(Pos(line, leftPos), Pos(line, findColumn(text, right, tabSize))));

         }

         if (!ranges.length) ranges.push(new Range(start, start));

         setSelection(doc, normalizeSelection(startSel.ranges.slice(0, ourIndex).concat(ranges), ourIndex), sel_mouse);

       } else {

         var oldRange = ourRange;

         var anchor = oldRange.anchor, head = pos;

         if (type != "single") {

           if (type == "double")

             var range = findWordAt(doc, pos);

           else

             var range = new Range(Pos(pos.line, 0), clipPos(doc, Pos(pos.line + 1, 0)));

           if (cmp(range.anchor, anchor) > 0) {

             head = range.head;

             anchor = minPos(oldRange.from(), range.anchor);

           } else {

             head = range.anchor;

             anchor = maxPos(oldRange.to(), range.head);

           }

         }

         var ranges = startSel.ranges.slice(0);

         ranges[ourIndex] = new Range(clipPos(doc, anchor), head);

         setSelection(doc, normalizeSelection(ranges, ourIndex), sel_mouse);

       }

     }

     var editorSize = display.wrapper.getBoundingClientRect();

     // Used to ensure timeout re-tries don't fire when another extend

     // happened in the meantime (clearTimeout isn't reliable -- at

     // least on Chrome, the timeouts still happen even when cleared,

     // if the clear happens after their scheduled firing time).

     var counter = 0;

     function extend(e) {

       var curCount = ++counter;