/*
    Copyright (C) 2010 Paul Davis 

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

*/

#include "pbd/command.h"

namespace PBD
{

class Stateful;	

/** A Command which stores its action as the differences between the before and after
 *  state of a Stateful object.
 */
class StatefulDiffCommand : public Command
{
public:
	StatefulDiffCommand (Stateful* s);
	~StatefulDiffCommand ();

	void operator() ();
	void undo ();

	XMLNode& get_state ();

private:
	Stateful* _object; ///< the object in question
	XMLNode* _before; ///< XML node containing the previous values of XML properties which changed
	XMLNode* _after; ///< XML node containing the new values of XML properties which changed
};

};