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/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the QtCore module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** No Commercial Usage
** This file contains pre-release code and may not be distributed.
** You may use this file in accordance with the terms and conditions
** contained in the either Technology Preview License Agreement or the
** Beta Release License Agreement.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain
** additional rights. These rights are described in the Nokia Qt LGPL
** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this
** package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3.0 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file. Please review the following information to
** ensure the GNU General Public License version 3.0 requirements will be
** met: http://www.gnu.org/copyleft/gpl.html.
**
** If you are unsure which license is appropriate for your use, please
** contact the sales department at http://www.qtsoftware.com/contact.
** $QT_END_LICENSE$
**
****************************************************************************/
#include "qwaitcondition.h"
#include "qmutex.h"
#include <pthread.h>
#define MIN(a,b) ((a)<(b)?(a):(b))
static void report_error(int code, const char *where, const char *what)
{
if (code != 0)
qWarning("%s: %s failure: %d", where, what, code);
}
class QWaitConditionPrivate
{
public:
pthread_mutex_t mutex;
pthread_cond_t cond;
int waiters;
int wakeups;
void wait()
{
int code;
for (;;)
{
code = pthread_cond_wait(&cond, &mutex);
if (code == 0 && wakeups == 0)
{
// many vendors warn of spurious wakeups from
// pthread_cond_wait(), especially after signal delivery,
// even though POSIX doesn't allow for it... sigh
continue;
}
break;
}
--waiters;
if (code == 0)
{
--wakeups;
}
else
{
report_error(code, "QWaitCondition::wait()", "cv wait");
}
report_error(pthread_mutex_unlock(&mutex), "QWaitCondition::wait()", "mutex unlock");
}
};
QWaitCondition::QWaitCondition()
{
d = new QWaitConditionPrivate;
report_error(pthread_mutex_init(&d->mutex, NULL), "QWaitCondition", "mutex init");
report_error(pthread_cond_init(&d->cond, NULL), "QWaitCondition", "cv init");
d->waiters = d->wakeups = 0;
}
QWaitCondition::~QWaitCondition()
{
report_error(pthread_cond_destroy(&d->cond), "QWaitCondition", "cv destroy");
report_error(pthread_mutex_destroy(&d->mutex), "QWaitCondition", "mutex destroy");
delete d;
}
void QWaitCondition::wakeOne()
{
report_error(pthread_mutex_lock(&d->mutex), "QWaitCondition::wakeOne()", "mutex lock");
d->wakeups = MIN(d->wakeups + 1, d->waiters);
report_error(pthread_cond_signal(&d->cond), "QWaitCondition::wakeOne()", "cv signal");
report_error(pthread_mutex_unlock(&d->mutex), "QWaitCondition::wakeOne()", "mutex unlock");
}
void QWaitCondition::wakeAll()
{
report_error(pthread_mutex_lock(&d->mutex), "QWaitCondition::wakeAll()", "mutex lock");
d->wakeups = d->waiters;
report_error(pthread_cond_broadcast(&d->cond), "QWaitCondition::wakeAll()", "cv broadcast");
report_error(pthread_mutex_unlock(&d->mutex), "QWaitCondition::wakeAll()", "mutex unlock");
}
void QWaitCondition::wait(QMutex *mutex)
{
if (!mutex) return;
report_error(pthread_mutex_lock(&d->mutex), "QWaitCondition::wait()", "mutex lock");
++d->waiters;
mutex->unlock();
d->wait();
mutex->lock();
}
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