Function patchDisplay

static/plugins/codemirror/codemirror.js:4227–4266

(cm, updateNumbersFrom, dims)

  // that are not there yet, and updating the ones that are out of
  // date.
  function patchDisplay(cm, updateNumbersFrom, dims) {
    var display = cm.display, lineNumbers = cm.options.lineNumbers;
    var container = display.lineDiv, cur = container.firstChild;

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

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

  function updateGutterSpace(display) {
    var width = display.gutters.offsetWidth;