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/****************************************************************************
**
** Copyright (C) 2012 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** This file is part of the QtCore module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Digia. For licensing terms and
** conditions see http://qt.digia.com/licensing. For further information
** use the contact form at http://qt.digia.com/contact-us.
**
** 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, Digia gives you certain additional
** rights. These rights are described in the Digia Qt LGPL Exception
** version 1.1, 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.
**
**
** $QT_END_LICENSE$
**
****************************************************************************/
#include "qplatformdefs.h"
#include "qwaitcondition.h"
#include "qmutex.h"
#include "qreadwritelock.h"
#include "qatomic.h"
#include "qstring.h"
#include "qmutex_p.h"
#include "qreadwritelock_p.h"
#include <errno.h>
#ifndef QT_NO_THREAD
QT_BEGIN_NAMESPACE
static void report_error(int code, const char *where, const char *what)
{
if (code != 0)
qWarning("%s: %s failure: %s", where, what, qPrintable(qt_error_string(code)));
}
class QWaitConditionPrivate {
public:
pthread_mutex_t mutex;
pthread_cond_t cond;
int waiters;
int wakeups;
bool wait(unsigned long time)
{
int code;
forever {
if (time != ULONG_MAX) {
struct timeval tv;
gettimeofday(&tv, 0);
timespec ti;
ti.tv_nsec = (tv.tv_usec + (time % 1000) * 1000) * 1000;
ti.tv_sec = tv.tv_sec + (time / 1000) + (ti.tv_nsec / 1000000000);
ti.tv_nsec %= 1000000000;
code = pthread_cond_timedwait(&cond, &mutex, &ti);
} else {
code = pthread_cond_wait(&cond, &mutex);
}
if (code == 0 && wakeups == 0) {
// many vendors warn of spurios wakeups from
// pthread_cond_wait(), especially after signal delivery,
// even though POSIX doesn't allow for it... sigh
continue;
}
break;
}
Q_ASSERT_X(waiters > 0, "QWaitCondition::wait", "internal error (waiters)");
--waiters;
if (code == 0) {
Q_ASSERT_X(wakeups > 0, "QWaitCondition::wait", "internal error (wakeups)");
--wakeups;
}
report_error(pthread_mutex_unlock(&mutex), "QWaitCondition::wait()", "mutex unlock");
if (code && code != ETIMEDOUT)
report_error(code, "QWaitCondition::wait()", "cv wait");
return (code == 0);
}
};
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 = qMin(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");
}
bool QWaitCondition::wait(QMutex *mutex, unsigned long time)
{
if (! mutex)
return false;
if (mutex->d->recursive) {
qWarning("QWaitCondition: cannot wait on recursive mutexes");
return false;
}
report_error(pthread_mutex_lock(&d->mutex), "QWaitCondition::wait()", "mutex lock");
++d->waiters;
mutex->unlock();
bool returnValue = d->wait(time);
mutex->lock();
return returnValue;
}
bool QWaitCondition::wait(QReadWriteLock *readWriteLock, unsigned long time)
{
if (!readWriteLock || readWriteLock->d->accessCount == 0)
return false;
if (readWriteLock->d->accessCount < -1) {
qWarning("QWaitCondition: cannot wait on QReadWriteLocks with recursive lockForWrite()");
return false;
}
report_error(pthread_mutex_lock(&d->mutex), "QWaitCondition::wait()", "mutex lock");
++d->waiters;
int previousAccessCount = readWriteLock->d->accessCount;
readWriteLock->unlock();
bool returnValue = d->wait(time);
if (previousAccessCount < 0)
readWriteLock->lockForWrite();
else
readWriteLock->lockForRead();
return returnValue;
}
QT_END_NAMESPACE
#endif // QT_NO_THREAD
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