transaction.h

/*
 For general Scribus (>=1.3.2) copyright and licensing information please refer
 to the COPYING file provided with the program. Following this notice may exist
 a copyright and/or license notice that predates the release of Scribus 1.3.2
 for which a new license (GPL+exception) is in place.
 */
/***************************************************************************
*   Copyright (C) 2008 by Andreas Vox                                     *
*                                                                         *
*   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.,                                       *
*   51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.             *
***************************************************************************/

#ifndef TRANSACTION_H
#define TRANSACTION_H

#include "scribusapi.h"

#include <QSharedData>
#include <QExplicitlySharedDataPointer>

class SCRIBUS_API Transaction {

public:
    enum Status {
        STATE_OPEN,
        STATE_WILLFAIL,
        STATE_FAILED,
        STATE_COMMITTED
    };
    
    class TransactionStateBase : public QSharedData
    {
    public:
        virtual ~TransactionStateBase() {};

        Status m_status;
    };
    
    Transaction(TransactionStateBase* data) : m_data(data)
    {
        if (data != 0)
            m_data->m_status = STATE_OPEN;
    }
    
    virtual ~Transaction() {};

    operator bool() const { return (m_data.constData() != 0); }
    
    virtual bool commit() = 0;
    
    virtual bool cancel() = 0;
    
    virtual void markFailed();

    virtual void reset();

    int getState() const;

    bool isNull() const { return (m_data.constData() == 0); }

    bool isStarted() const { return (m_data.constData() != 0); }

    bool isOpened() const;
    
protected:
    // if you subclass, do *not* add any data members but use this pointer instead,
    // otherwise the copy initializer will strip your objects.
    QExplicitlySharedDataPointer<TransactionStateBase>    m_data;
};

#endif