Function makeChangeFromHistory

tools/pythonauto/static/codemirrorepl/codemirror.js:3300–3362

(doc, type, allowSelectionOnly)

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

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

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

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

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

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

    for (var i = event.changes.length - 1; i >= 0; --i) {
      var change = event.changes[i];
      change.origin = type;
      if (filter && !filterChange(doc, change, false)) {
        source.length = 0;
        return;
      }

      antiChanges.push(historyChangeFromChange(doc, change));

      var after = i ? computeSelAfterChange(doc, change, null) : lst(source);
      makeChangeSingleDoc(doc, change, after, mergeOldSpans(doc, change));
      if (doc.cm) ensureCursorVisible(doc.cm);
      var rebased = [];

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