ProjectJournal.h

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/*
 * ProjectJournal.h - declaration of class ProjectJournal
 *
 * Copyright (c) 2006-2010 Tobias Doerffel <tobydox/at/users.sourceforge.net>
 *
 * This file is part of LMMS - https://lmms.io
 *
 * 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 (see COPYING); if not, write to the
 * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301 USA.
 *
 */
 
#ifndef LMMS_PROJECT_JOURNAL_H
#define LMMS_PROJECT_JOURNAL_H
 
#include <QHash>
#include <QStack>
 
#include "LmmsTypes.h"
#include "DataFile.h"
 
 
namespace lmms
{
 
 
class JournallingObject;
 

class ProjectJournal
{
public:
        static const int MAX_UNDO_STATES;
 
        ProjectJournal();
        virtual ~ProjectJournal() = default;
 
        void undo();
        void redo();
 
        bool canUndo() const;
        bool canRedo() const;
 
        void addJournalCheckPoint( JournallingObject *jo );
 
        bool isJournalling() const
        {
                return m_journalling;
        }
 
        void setJournalling( const bool _on )
        {
                m_journalling = _on;
        }
 
        // alloc new ID and register object _obj to it
        jo_id_t allocID( JournallingObject * _obj );
 
        // if there's already something known about ID _id, but it is currently
        // unused (e.g. after jouralling object was deleted), register object
        // _obj to this id
        void reallocID( const jo_id_t _id, JournallingObject * _obj );
 
        // make ID _id unused, but keep all global journalling information
        // (order of journalling entries etc.) referring to _id - needed for
        // restoring a journalling object later
        void freeID( const jo_id_t _id )
        {
                reallocID( _id, nullptr );
        }

        static jo_id_t idToSave( jo_id_t id );
        static jo_id_t idFromSave( jo_id_t id );
 
        void clearJournal();
        void stopAllJournalling();
        JournallingObject * journallingObject( const jo_id_t _id )
        {
                if( m_joIDs.contains( _id ) )
                {
                        return m_joIDs[_id];
                }
                return nullptr;
        }
 
 
private:
        using JoIdMap = QHash<jo_id_t, JournallingObject*>;
 
        struct CheckPoint
        {
                CheckPoint( jo_id_t initID = 0, const DataFile& initData = DataFile( DataFile::Type::JournalData ) ) :
                        joID( initID ),
                        data( initData )
                {
                }
                jo_id_t joID;
                DataFile data;
        } ;
        using CheckPointStack = QStack<CheckPoint>;
 
        JoIdMap m_joIDs;
 
        CheckPointStack m_undoCheckPoints;
        CheckPointStack m_redoCheckPoints;
 
        bool m_journalling;
 
} ;
 
 
} // namespace lmms
 
#endif // LMMS_PROJECT_JOURNAL_H