RunGuard.h

/*
Copyright (C) 2010-2017 Christopher Brochtrup

This file is part of Capture2Text.

Capture2Text 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.

Capture2Text 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 Capture2Text.  If not, see <http://www.gnu.org/licenses/>.
*/

#ifndef RUNGUARD_H
#define RUNGUARD_H

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

// Taken from:
// https://stackoverflow.com/questions/5006547/qt-best-practice-for-a-single-instance-app-protection
class RunGuard
{

public:
    RunGuard( const QString& key );
    ~RunGuard();

    bool isAnotherRunning();
    bool tryToRun();
    void release();

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

    QSharedMemory sharedMem;
    QSystemSemaphore memLock;

    Q_DISABLE_COPY( RunGuard )
};


#endif // RUNGUARD_H