undo.h

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/* 
    Copyright (C) 2002 Brett Viren & 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.

*/

#ifndef __lib_pbd_undo_h__
#define __lib_pbd_undo_h__

#include <string>
#include <list>
#include <map>
#include <sigc++/slot.h>
#include <sigc++/bind.h>
#ifndef  COMPILER_MSVC
#include <sys/time.h>
#else
#include <ardourext/misc.h>
#endif

#include "pbd/libpbd_visibility.h"
#include "pbd/command.h"

typedef sigc::slot<void> UndoAction;

class LIBPBD_API UndoTransaction : public Command
{
  public:
        UndoTransaction ();
        UndoTransaction (const UndoTransaction&);
        UndoTransaction& operator= (const UndoTransaction&);
        ~UndoTransaction ();

        void clear ();
        bool empty() const;
        bool clearing () const { return _clearing; }

        void add_command (Command* const);
        void remove_command (Command* const);

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

        XMLNode &get_state();

        void set_timestamp (struct timeval &t) {
                _timestamp = t;
        }

        const struct timeval& timestamp() const {
                return _timestamp;
        }

  private:
        std::list<Command*>    actions;
        struct timeval        _timestamp;
        bool                  _clearing;

        friend void command_death (UndoTransaction*, Command *);
        
        void about_to_explicitly_delete ();
};

class LIBPBD_API UndoHistory : public PBD::ScopedConnectionList
{
  public:
        UndoHistory();
        ~UndoHistory() {}
        
        void add (UndoTransaction* ut);
        void undo (unsigned int n);
        void redo (unsigned int n);
        
        unsigned long undo_depth() const { return UndoList.size(); }
        unsigned long redo_depth() const { return RedoList.size(); }
        
        std::string next_undo() const { return (UndoList.empty() ? std::string() : UndoList.back()->name()); }
        std::string next_redo() const { return (RedoList.empty() ? std::string() : RedoList.back()->name()); }

        void clear ();
        void clear_undo ();
        void clear_redo ();

        /* returns all or part of the history.
           If depth==0 it returns just the top
           node. If depth<0, it returns everything.
           If depth>0, it returns state for that
           many elements of the history, or 
           the full history, whichever is smaller.
        */

        XMLNode &get_state(int32_t depth = 0);
        void save_state();

        void set_depth (uint32_t);

        PBD::Signal0<void> Changed;
        PBD::Signal0<void> BeginUndoRedo;
        PBD::Signal0<void> EndUndoRedo;
        
  private:
        bool _clearing;
        uint32_t _depth;
        std::list<UndoTransaction*> UndoList;
        std::list<UndoTransaction*> RedoList;

        void remove (UndoTransaction*);
};


#endif /* __lib_pbd_undo_h__ */