/// <summary> Performs the given action and adds it to the undoable stack. </summary>
/// <param name="undoableAction"> The undoable action. </param>
public void Do(UndoableAction undoableAction)
{
bool wasMerged = false;
var newestEntry = new UndoStackEntry(undoableAction, DateTimeOffset.UtcNow);
if (_toUndoStack.Count > 0)
{
var lastEntry = _toUndoStack.Peek();
if (_mergePolicy.ShouldTryMerge(lastEntry, newestEntry))
{
wasMerged = lastEntry.Action.TryMerge(_context, undoableAction);
}
}
undoableAction.Do(_context);
if (!wasMerged)
{
// it was merged into the previous command, so no need to add it to the stack
_toUndoStack.Push(newestEntry);
}
_toRedoStack.Clear();
}
public UndoStackEntry(UndoableAction action, DateTimeOffset insertTime)
{
Action = action;
InsertTime = insertTime;
}
/// <summary> Attempts to merge the given action into this instance. </summary>
/// <param name="context"> The context in which the action should be merged. </param>
/// <param name="action"> The action to merge, if possible. </param>
/// <returns> True if the action was merged, false otherwise. </returns>
public virtual bool TryMerge(DocumentEditorContext context, UndoableAction action)
{
return(false);
}