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/****************************************************************************
*
* (c) 2009-2016 QGROUNDCONTROL PROJECT <http://www.qgroundcontrol.org>
*
* QGroundControl is licensed according to the terms in the file
* COPYING.md in the root of the source code directory.
*
****************************************************************************/
#include "RunGuard.h"
#include <QCryptographicHash>
namespace
{
QString generateKeyHash( const QString& key, const QString& salt )
{
QByteArray data;
data.append( key.toUtf8() );
data.append( salt.toUtf8() );
data = QCryptographicHash::hash( data, QCryptographicHash::Sha1 ).toHex();
return data;
}
}
RunGuard::RunGuard( const QString& key )
: key( key )
, memLockKey( generateKeyHash( key, "_memLockKey" ) )
, sharedmemKey( generateKeyHash( key, "_sharedmemKey" ) )
, sharedMem( sharedmemKey )
, memLock( memLockKey, 1 )
{
memLock.acquire();
{
QSharedMemory fix( sharedmemKey ); // Fix for *nix: http://habrahabr.ru/post/173281/
fix.attach();
}
memLock.release();
}
RunGuard::~RunGuard()
{
release();
}
bool RunGuard::isAnotherRunning()
{
if ( sharedMem.isAttached() )
return false;
memLock.acquire();
const bool isRunning = sharedMem.attach();
if ( isRunning )
sharedMem.detach();
memLock.release();
return isRunning;
}
bool RunGuard::tryToRun()
{
if ( isAnotherRunning() ) // Extra check
return false;
memLock.acquire();
const bool result = sharedMem.create( sizeof( quint64 ) );
memLock.release();
if ( !result )
{
release();
return false;
}
return true;
}
void RunGuard::release()
{
memLock.acquire();
if ( sharedMem.isAttached() )
sharedMem.detach();
memLock.release();
}