Switch to a dummy cursor to force doc width in non-wrapping mode

This prevents situations where the cursor will cause a scrollbar, but the
rest of the code doesn't realize this. Also removes the lineSpace.style.width
setting code, which appears to have been broken in several different ways.

Closes #550

lib/codemirror.js

@@ -30,8 +30,10 @@ var CodeMirror = (function() {
             '<div class="CodeMirror-gutter"><div class="CodeMirror-gutter-text"></div></div>' +
             // Provides positioning relative to (visible) text origin
             '<div class="CodeMirror-lines"><div style="position: relative; z-index: 0">' +
+              // Used to measure text size
               '<div style="position: absolute; width: 100%; height: 0; overflow: hidden; visibility: hidden;"></div>' +
               '<pre class="CodeMirror-cursor">&#160;</pre>' + // Absolutely positioned blinky cursor
+              '<pre class="CodeMirror-cursor" style="visibility: hidden">&#160;</pre>' + // Used to force a width
               '<div style="position: relative; z-index: -1"></div><div></div>' + // DIVs containing the selection and the actual code
             '</div></div></div></div></div>';
     if (place.appendChild) place.appendChild(wrapper); else place(wrapper);
@@ -40,10 +42,9 @@ var CodeMirror = (function() {
         scroller = wrapper.lastChild, code = scroller.firstChild,
         mover = code.firstChild, gutter = mover.firstChild, gutterText = gutter.firstChild,
         lineSpace = gutter.nextSibling.firstChild, measure = lineSpace.firstChild,
-        cursor = measure.nextSibling, selectionDiv = cursor.nextSibling,
-        lineDiv = selectionDiv.nextSibling,
-        scrollbar = inputDiv.nextSibling,
-        scrollbarInner = scrollbar.firstChild;
+        cursor = measure.nextSibling, widthForcer = cursor.nextSibling,
+        selectionDiv = widthForcer.nextSibling, lineDiv = selectionDiv.nextSibling,
+        scrollbar = inputDiv.nextSibling, scrollbarInner = scrollbar.firstChild;
     themeChanged(); keyMapChanged();
     // Needed to hide big blue blinking cursor on Mobile Safari
     if (ios) input.style.width = "0px";
@@ -94,15 +95,15 @@ var CodeMirror = (function() {
     // Variables used by startOperation/endOperation to track what
     // happened during the operation.
     var updateInput, userSelChange, changes, textChanged, selectionChanged, leaveInputAlone,
-        gutterDirty, callbacks, maxLengthChanged;
+        gutterDirty, callbacks;
     // Current visible range (may be bigger than the view window).
     var displayOffset = 0, showingFrom = 0, showingTo = 0, lastSizeC = 0;
     // bracketHighlighted is used to remember that a bracket has been
     // marked.
     var bracketHighlighted;
     // Tracks the maximum line length so that the horizontal scrollbar
     // can be kept static when scrolling.
-    var maxLine = "", maxWidth;
+    var maxLine = "", updateMaxLine = false, maxLineChanged = true;
     var tabCache = {};
 
     // Initialize the content.
@@ -789,11 +790,11 @@ var CodeMirror = (function() {
         doc.iter(from.line, from.line + newText.length, function(line) {
           var l = line.text;
           if (!line.hidden && l.length > maxLineLength) {
-            maxLine = l; maxLineLength = l.length; maxWidth = null;
+            maxLine = l; maxLineLength = l.length; maxLineChanged = true;
             recomputeMaxLength = false;
           }
         });
-        if (recomputeMaxLength) maxLengthChanged = true;
+        if (recomputeMaxLength) updateMaxLine = true;
       }
 
       // Add these lines to the work array, so that they will be
@@ -853,14 +854,14 @@ var CodeMirror = (function() {
 
     function computeMaxLength() {
       var maxLineLength = 0; 
-      maxLine = ""; maxWidth = null;
+      maxLine = ""; maxLineChanged = true;
       doc.iter(0, doc.size, function(line) {
         var l = line.text;
         if (!line.hidden && l.length > maxLineLength) {
           maxLineLength = l.length; maxLine = l;
         }
       });
-      maxLengthChanged = false;
+      updateMaxLine = false;
     }
 
     function replaceRange(code, from, to) {
@@ -1073,7 +1074,6 @@ var CodeMirror = (function() {
                         " nodes=" + lineDiv.childNodes.length);
 
       function checkHeights() {
-        maxWidth = scroller.clientWidth;
         var curNode = lineDiv.firstChild, heightChanged = false;
         doc.iter(showingFrom, showingTo, function(line) {
           if (!line.hidden) {
@@ -1096,25 +1096,15 @@ var CodeMirror = (function() {
         var virtualHeight = Math.floor(doc.height * th + 2 * paddingTop()), scrollbarHeight = scroller.clientHeight;
         if (virtualHeight > scrollbarHeight) scrollbar.style.display = "block";
         checkHeights();
-      } else {
-        if (maxWidth == null) maxWidth = stringWidth(maxLine);
-        if (maxWidth > scroller.clientWidth) {
-          lineSpace.style.width = maxWidth + "px";
-          // Needed to prevent odd wrapping/hiding of widgets placed in here.
-          code.style.width = "";
-          code.style.width = scroller.scrollWidth + "px";
-        } else {
-          lineSpace.style.width = code.style.width = "";
-        }
       }
 
       gutter.style.display = gutterDisplay;
       if (different || gutterDirty) {
         // If the gutter grew in size, re-check heights. If those changed, re-draw gutter.
         updateGutter() && options.lineWrapping && checkHeights() && updateGutter();
       }
-      updateVerticalScroll(scrollTop);
       updateSelection();
+      updateVerticalScroll(scrollTop);
       if (!suppressCallback && options.onUpdate) options.onUpdate(instance);
       return true;
     }
@@ -1467,9 +1457,10 @@ var CodeMirror = (function() {
           if (guess != 1) updateLineHeight(line, guess);
         });
         lineSpace.style.width = code.style.width = "";
+        widthForcer.style.left = "";
       } else {
         wrapper.className = wrapper.className.replace(" CodeMirror-wrap", "");
-        maxWidth = null; maxLine = "";
+        maxLine = ""; maxLineChanged = true;
         doc.iter(0, doc.size, function(line) {
           if (line.height != 1 && !line.hidden) updateLineHeight(line, 1);
           if (line.text.length > maxLine.length) maxLine = line.text;
@@ -1602,10 +1593,9 @@ var CodeMirror = (function() {
           if (!options.lineWrapping) {
             var l = line.text;
             if (hidden && l.length == maxLine.length) {
-              maxLengthChanged = true;
+              updateMaxLine = true;
             } else if (!hidden && l.length > maxLine.length) {
-              maxLine = l; maxWidth = null;
-              maxLengthChanged = false;
+              maxLine = l; maxWidth = null; updateMaxLine = false;
             }
           }
           updateLineHeight(line, hidden ? 0 : 1);
@@ -1958,8 +1948,12 @@ var CodeMirror = (function() {
       changes = []; selectionChanged = false; callbacks = [];
     }
     function endOperation() {
+      if (updateMaxLine) computeMaxLength();
+      if (maxLineChanged && !options.lineWrapping) {
+        widthForcer.style.left = stringWidth(maxLine) + "px";
+        maxLineChanged = false;
+      }
       var newScrollPos, updated;
-      if (maxLengthChanged) computeMaxLength();
       if (selectionChanged) {
         var coords = calculateCursorCoords();
         newScrollPos = calculateScrollPos(coords.x, coords.y, coords.x, coords.yBot);