/// <summary>
/// Pushes new action to the stack.
/// </summary>
public void Add(EditAction action)
{
if (_GroupingUndoChain != null)
{
// put given action to the head of the chain
action.Next = _GroupingUndoChain;
_GroupingUndoChain = action;
}
else
{
// if there is no more space, expand buffer
if (_Stack.Length <= _NextIndex)
{
Utl.ResizeArray(ref _Stack, _Stack.Length + GrowSize);
}
// stack up this action
_Stack[_NextIndex] = action;
_NextIndex++;
if (_NextIndex < _Stack.Length)
{
_Stack[_NextIndex] = null;
}
}
}
/// <summary>
/// Begins grouping up editing actions into a single UNDO action.
/// </summary>
public void BeginUndo()
{
if (_GroupingUndoChain == null)
{
_GroupingUndoChain = new EditAction(null,
0, null, null,
0, 0, null);
}
_GroupUndoDepth++;
}
public void SetSavedState()
{
if (0 < _NextIndex)
{
_LastSavedAction = _Stack[_NextIndex - 1];
}
else
{
_LastSavedAction = null;
}
}
/// <summary>
/// Gets the action most recently done and remove it from stack.
/// </summary>
public EditAction GetRedoAction()
{
if (_NextIndex < _Stack.Length &&
_Stack[_NextIndex] != null)
{
EditAction redoAction = _Stack[_NextIndex];
_NextIndex++;
return(redoAction);
}
return(null);
}
/// <summary>
/// Ends grouping up editing actions.
/// </summary>
public void EndUndo()
{
_GroupUndoDepth--;
if (_GroupUndoDepth <= 0)
{
if (_GroupingUndoChain != null)
{
EditAction groupedAction = _GroupingUndoChain;
_GroupingUndoChain = null;
if (groupedAction.HasNoEffect == false)
{
Add(groupedAction);
}
}
_GroupUndoDepth = 0;
}
}