protected bool ExecuteActionInternal(IUndoableAction action, bool clearRedoStack)
{
OnBeforeStateChanged();
if (!action.Execute())
{
return(false);
}
if (clearRedoStack)
{
redoStack.Clear();
}
var undoGroup = action.GetUndoGroup();
// Should we group together this undo step with more of the same kind?
if (undoGroup != 0)
{
if (currentGroup == null || currentGroup.CaughtGroup != undoGroup)
{
currentGroup = new UndoableActionGroup(undoGroup);
AddToUndoStack(currentGroup);
}
currentGroup.Actions.Add(action);
}
else
{
AddToUndoStack(action);
}
OnAfterStateChanged();
return(true);
}
/// <summary>
/// Force the current undo group to stop. For example, if you're painting some tiles and
/// stop for a moment, you might want to split the undo group at that point in order
/// to separate undo steps by stroke. Call this function to do so.
/// </summary>
/// <param name="group">Id of the group we want to end.</param>
public void EndUndoGroup(int group)
{
if (currentGroup != null && currentGroup.CaughtGroup == group)
{
currentGroup = null;
}
}
/// <summary>
/// Clear entire undo state.
/// </summary>
public void Clear()
{
OnBeforeStateChanged();
currentGroup = null;
undoStack.Clear();
redoStack.Clear();
OnAfterStateChanged();
}
/// <summary>
/// Redo a single action.
/// </summary>
public void Redo()
{
currentGroup = null;
if (redoStack.Count > 0)
{
var action = redoStack[redoStack.Count - 1];
redoStack.RemoveAt(redoStack.Count - 1);
ExecuteActionInternal(action, false);
OnRedoEvent(action);
}
}
/// <summary>
/// Undo a single action.
/// </summary>
public void Undo()
{
currentGroup = null;
if (undoStack.Count > 0)
{
OnBeforeStateChanged();
var action = undoStack[undoStack.Count - 1];
undoStack.RemoveAt(undoStack.Count - 1);
action.Undo();
redoStack.Add(action);
OnUndoEvent(action);
OnAfterStateChanged();
}
}
