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#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();
{
// Fix for *nix: http://habrahabr.ru/post/173281/
QSharedMemory fix(sharedmemKey);
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()
{
// Extra check
if (isAnotherRunning())
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();
}