runguard.h

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/*
 * 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 3 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, see <http://www.gnu.org/licenses/>
 *
 * Additional note on redistribution: The copyright and license notices above
 * must be maintained in each individual source file that is a derivative work
 * of this source file; otherwise redistribution is prohibited.
 */

#ifndef RUNGUARD_H
#define RUNGUARD_H

#include "runguard_global.h"

#include <QObject>
#include <QSharedMemory>
#include <QSystemSemaphore>


class RUNGUARD_EXPORT RunGuard
{

public:
    static RunGuard &instance(const QString &key);

    bool tryToRun();
    quint64 secondaryAttempts();

private:
    const QString key;
    const QString memLockKey;
    const QString sharedmemKey;

    QSharedMemory sharedMem;
    QSystemSemaphore memLock;

    RunGuard(const QString &key = QString());
    ~RunGuard();

    bool isAnotherRunning();
    void release();

    Q_DISABLE_COPY(RunGuard)
};

#endif // RUNGUARD_H