/// <summary>
/// Push a new <see cref="IAction"/> onto the <see cref="WUndoStack"/>, or merges it with the most recently executed command.
/// This function executes the <see cref="IAction.Redo"/> function in either case. Calling this will clear the <see cref="WUndoStack"/>'s
/// Redo stack, so the command will always end up being the top-most on the stack.
/// </summary>
/// <param name="command"></param>
public void Push(WUndoCommand command)
{
// If we have an open macro, we push it to the macro instead of the stack, and when the macro is ended, that is when it is finally pushed to the stack.
// command.GetType().IsSubclassOf(typeof(WUndoCommand)) will return false if we're pushing a WUndoCommand, ie: the end of a macro.
if (m_macroParent != null && command.GetType().IsSubclassOf(typeof(WUndoCommand)))
{
command.SetParent(m_macroParent);
return;
}
// Clear the redo stack when we add a new item to the undo stack.
m_redoStack.Clear();
// Call the Redo function to apply the state change encapsulated by the IAction.
command.Redo();
// Attempt to merge with our new action. If this fails, add our new action to the undo stack.
WUndoCommand latestAction = m_undoStack.Peek();
if (latestAction == null)
{
m_undoStack.Push(command);
}
else if (!latestAction.MergeWith(command))
{
m_undoStack.Push(command);
}
}
/// <summary>
/// Calling this function clears both the undo and redo stack. This should be
/// used when a map is closed so that we free all references to objects in that
/// map.
/// </summary>
public void Clear()
{
m_undoStack.Clear();
m_redoStack.Clear();
}
