QSingleApplication
? QMutex
? QSharedMemory
?我正在寻找能够在 Windows、OSX 和 Linux (Ubuntu) 中顺利运行的东西。使用 Qt 4.7.1
简单的解决方案,即可满足您的要求。没有网络依赖(如QtSingleApplication
)并且没有任何开销。
Usage:
int main()
{
RunGuard guard( "some_random_key" );
if ( !guard.tryToRun() )
return 0;
QAppplication a(/*...*/);
// ...
}
运行卫士.h
#ifndef RUNGUARD_H
#define RUNGUARD_H
#include <QObject>
#include <QSharedMemory>
#include <QSystemSemaphore>
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
运行卫士.cpp
#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();
}
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