/// <summary>
/// Disposes the this mementor and clears redo and undo stacks.
/// This method won't fire <see cref="Changed"/> event.
/// </summary>
public void Dispose()
{
Changed = null;
_undoStack.Clear();
_redoStack.Clear();
_currentBatch = null;
}
private BaseEvent InternalEndBatch(BatchEvent stack)
{
BaseEvent processed = ProcessBatch(_currentBatch);
if (processed != null)
{
stack.Push(processed);
}
_currentBatch = null;
return(processed);
}
private BaseEvent ProcessBatch(BatchEvent batchEvent)
{
if (batchEvent.Count == 0)
{
return(null);
}
if (batchEvent.Count == 1)
{
return(batchEvent.Pop());
}
return(batchEvent);
}
/// <summary>
/// Explicitly marks the beginning of a batch. Use this instead of <see cref="Batch"/>
/// changes can be made in different places instead of inside one certain block of code.
/// When finish, end the batch by invoking <see cref="EndBatch"/>.
/// </summary>
public void BeginBatch()
{
if (!IsTrackingEnabled)
{
return;
}
if (IsInBatch)
{
throw new InvalidOperationException("Re-entrant batch is not supported");
}
_currentBatch = new BatchEvent();
}
/// <summary>
/// Resets the state of this <see cref="Mementor"/> object to its initial state.
/// This effectively clears the redo stack, undo stack and current batch (if one is active).
/// </summary>
public void Reset()
{
bool shouldNotify = UndoCount > 0 || RedoCount > 0;
_undoStack.Clear();
_redoStack.Clear();
_currentBatch = null;
IsTrackingEnabled = true;
if (shouldNotify)
{
NotifyChange(null);
}
}
protected internal override BaseEvent Rollback()
{
var batch = new BatchEvent();
while (Count > 0)
{
var reverse = Pop().Rollback();
if (reverse == null)
{
continue;
}
if (reverse is BatchEvent)
{
throw new InvalidOperationException("Must not return BatchEvent in Rollback()");
}
batch.Push(reverse);
}
return(batch);
}
internal BatchEvent(BatchEvent other = null)
{
_events = other == null
? new Stack <BaseEvent>()
: new Stack <BaseEvent>(other._events.Reverse());
}