qsystemsemaphore.cpp

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#include "qsystemsemaphore.h"
#include "qsystemsemaphore_p.h"
#include <qglobal.h>

QT_BEGIN_NAMESPACE

#ifndef QT_NO_SYSTEMSEMAPHORE

QSystemSemaphore::QSystemSemaphore(const QString &key, int initialValue, AccessMode mode)
    : d(new QSystemSemaphorePrivate)
{
    setKey(key, initialValue, mode);
}

QSystemSemaphore::~QSystemSemaphore()
{
    d->cleanHandle();
}

void QSystemSemaphore::setKey(const QString &key, int initialValue, AccessMode mode)
{
    if (key == d->key && mode == Open)
        return;
    d->error = NoError;
    d->errorString = QString();
#if !defined(Q_OS_WIN) && !defined(Q_OS_SYMBIAN) && !defined(QT_POSIX_IPC)
    // optimization to not destroy/create the file & semaphore
    if (key == d->key && mode == Create && d->createdSemaphore && d->createdFile) {
        d->initialValue = initialValue;
        d->unix_key = -1;
        d->handle(mode);
        return;
    }
#endif
    d->cleanHandle();
    d->key = key;
    d->initialValue = initialValue;
    // cache the file name so it doesn't have to be generated all the time.
    d->fileName = d->makeKeyFileName();
    d->handle(mode);
}

QString QSystemSemaphore::key() const
{
    return d->key;
}

bool QSystemSemaphore::acquire()
{
    return d->modifySemaphore(-1);
}

bool QSystemSemaphore::release(int n)
{
    if (n == 0)
        return true;
    if (n < 0) {
        qWarning("QSystemSemaphore::release: n is negative.");
        return false;
    }
    return d->modifySemaphore(n);
}

QSystemSemaphore::SystemSemaphoreError QSystemSemaphore::error() const
{
    return d->error;
}

QString QSystemSemaphore::errorString() const
{
    return d->errorString;
}

#endif // QT_NO_SYSTEMSEMAPHORE

QT_END_NAMESPACE