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/***************************************************************************
 *   Copyright (C) 2007 by Peter Gaede   *
 *   develop@linux-peter.de   *
 *                                                                         *
 *   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.,                                       *
 *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
 ***************************************************************************/

#ifndef SINGLEAPPLICATION_H
#define SINGLEAPPLICATION_H

#include <QApplication>

class SingleApplication : public QApplication
{
	Q_OBJECT

	public:
		SingleApplication(const QString &lockFile, int &argc, char **argv);
		~SingleApplication();

		bool isRunning() const;
		QString lockFile() const;

	private:
		bool m_isRunning;
		QString m_lockFile;
		
		bool checkForRunningInstance();
};

#endif // SINGLEAPPLICATION_H

Code: Alles auswählen

/***************************************************************************
 *   Copyright (C) 2007 by Peter Gaede   *
 *   develop@linux-peter.de   *
 *                                                                         *
 *   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.,                                       *
 *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
 ***************************************************************************/

#include "singleapplication.h"
#include <QFile>
#include <QProcess>
#include <QWidget>
#include <QMessageBox>
#include <QDir>
#include <unistd.h>

SingleApplication::SingleApplication(const QString &lockFile, int &argc, char **argv)
	: QApplication(argc, argv)
{
	m_lockFile = QString("%1/%2").arg(QDir::tempPath()).arg(lockFile);
	m_isRunning = checkForRunningInstance();
}

SingleApplication::~SingleApplication()
{
	if (!m_isRunning)
	{
		QFile file(m_lockFile);
		if (file.exists())
			file.remove();
	}
}

bool SingleApplication::checkForRunningInstance()
{
	QFile file(m_lockFile);

	// Check if lock file exists
	if (file.exists())
	{
		// Now we check if a previous instance are running
		if (file.open(QIODevice::Text | QIODevice::ReadOnly))
		{
			QString pid = QString(file.readLine());
			file.close();

			if (!pid.isEmpty())
			{
				QProcess p;

				p.start("ps", QStringList() << "--pid" << pid);
				p.waitForFinished();

				QString data = QString(p.readAllStandardOutput());
				if (data.contains(pid))
					return true;
			}
		}
		else
		{
			QWidget w;
			QMessageBox::critical(&w, tr("Lock file error"), QString(tr("Unable to open lock file for reading:\n%1")).arg(m_lockFile));
			return true;
		}
	}

	// We are the only one instance, now we write our pid to lock file
	if (file.open(QIODevice::Text | QIODevice::WriteOnly))
	{
		file.resize(0);
		file.write(QString::number(getpid()).toAscii());
		file.close();
	}
	else
	{
		QWidget w;
		QMessageBox::critical(&w, tr("Lock file error"), QString(tr("Unable open lock file for writing:\n%1")).arg(m_lockFile));
		return true;
	}

	return false;
}

QString SingleApplication::lockFile() const
{
	return m_lockFile;
}

bool SingleApplication::isRunning() const
{
	return m_isRunning;
}

Code: Alles auswählen

#include "singleapplication.h"
#include <QDialog>

int main(int argc, char **argv)
{
	SingleApplication app(".singleapptest_lock", argc, argv);
	if (app.isRunning())
		return 0;
    
    QDialog d;
    d.show();

    app.connect(&app, SIGNAL(lastWindowClosed()), &app, SLOT(quit()));
    return app.exec();
}

Code: Alles auswählen

int main(int argc, char *argv[]){

  QApplication app(argc, argv);

  SomeClass window;

  if(QDBusConnection::sessionBus().registerService("org.example")){
    window.show();
    return app.exec();
  }
}