internal void CloseUndoGroup()
{
if (null != currentUndoGroup)
{
undoStack.Add(currentUndoGroup);
currentUndoGroup = null;
}
}
internal void Undo(ref Point cursorPosition)
{
CloseUndoGroup();
if (undoStack.Count == 0)
return;
ModificationGroup topMostGroup = undoStack[undoStack.Count - 1];
topMostGroup.ReverseModifications();
foreach (Modification modification in topMostGroup.List)
UndoModification(modification, ref cursorPosition);
// Redo group is always closed immediately.
if (null != currentRedoGroup)
{
redoStack.Add(currentRedoGroup);
currentRedoGroup = null;
}
undoStack.RemoveAt(undoStack.Count - 1);
}
private void RecordInsertionInternal(int lineInsertedAt, int newLineCount, List<string> originalContents, Point cursorPosition)
{
if (currentUndoGroup == null)
currentUndoGroup = new ModificationGroup();
if (currentUndoGroup.ModificationCount == 1)
{
Modification lastModification = currentUndoGroup.GetLastModification();
if (null != lastModification && (false != lastModification.IsInsertion) && lastModification.StartLine == lineInsertedAt)
return; // Insertions after another insertion are ignored.
}
currentUndoGroup.Add(new Modification(lineInsertedAt, newLineCount,
originalContents, Modification.Action.Insert, cursorPosition));
}
private void RecordRemovalInternal(int lineRemovedAt, int lineCount, List<string> originalContents, Point cursorPosition)
{
if (currentUndoGroup == null)
currentUndoGroup = new ModificationGroup();
else
{
Modification lastModification = currentUndoGroup.GetLastModification();
if (null != lastModification)
{
if (false != lastModification.IsRemoval)
return;
if (false != lastModification.IsInsertion)
{
CloseUndoGroup();
currentUndoGroup = new ModificationGroup();
}
}
}
currentUndoGroup.Add(new Modification(lineRemovedAt, lineCount,
originalContents, Modification.Action.Remove, cursorPosition));
}
private void AddRemoveToRedoGroup(int lineInsertedAt, int newLineCount, List<string> originalContents, Point cursorPosition)
{
if (currentRedoGroup == null)
currentRedoGroup = new ModificationGroup();
currentRedoGroup.Add(new Modification(lineInsertedAt, newLineCount,
originalContents, Modification.Action.Remove, cursorPosition));
}