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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 "qwaitcondition.h"
#include "qnamespace.h"
#include "qmutex.h"
#include "qreadwritelock.h"
#include "qlist.h"
#include "qalgorithms.h"
#include "qt_windows.h"
#ifndef QT_NO_THREAD
#define Q_MUTEX_T void*
#include <private/qmutex_p.h>
#include <private/qreadwritelock_p.h>
QT_BEGIN_NAMESPACE
//***********************************************************************
// QWaitConditionPrivate
// **********************************************************************
class QWaitConditionEvent
{
public:
inline QWaitConditionEvent() : priority(0), wokenUp(false)
{
event = CreateEvent(NULL, TRUE, FALSE, NULL);
}
inline ~QWaitConditionEvent() { CloseHandle(event); }
int priority;
bool wokenUp;
HANDLE event;
};
typedef QList<QWaitConditionEvent *> EventQueue;
class QWaitConditionPrivate
{
public:
QMutex mtx;
EventQueue queue;
EventQueue freeQueue;
QWaitConditionEvent *pre();
bool wait(QWaitConditionEvent *wce, unsigned long time);
void post(QWaitConditionEvent *wce, bool ret);
};
QWaitConditionEvent *QWaitConditionPrivate::pre()
{
mtx.lock();
QWaitConditionEvent *wce =
freeQueue.isEmpty() ? new QWaitConditionEvent : freeQueue.takeFirst();
wce->priority = GetThreadPriority(GetCurrentThread());
wce->wokenUp = false;
// insert 'wce' into the queue (sorted by priority)
int index = 0;
for (; index < queue.size(); ++index) {
QWaitConditionEvent *current = queue.at(index);
if (current->priority < wce->priority)
break;
}
queue.insert(index, wce);
mtx.unlock();
return wce;
}
bool QWaitConditionPrivate::wait(QWaitConditionEvent *wce, unsigned long time)
{
// wait for the event
bool ret = false;
switch (WaitForSingleObject(wce->event, time)) {
default: break;
case WAIT_OBJECT_0:
ret = true;
break;
}
return ret;
}
void QWaitConditionPrivate::post(QWaitConditionEvent *wce, bool ret)
{
mtx.lock();
// remove 'wce' from the queue
queue.removeAll(wce);
ResetEvent(wce->event);
freeQueue.append(wce);
// wakeups delivered after the timeout should be forwarded to the next waiter
if (!ret && wce->wokenUp && !queue.isEmpty()) {
QWaitConditionEvent *other = queue.first();
SetEvent(other->event);
other->wokenUp = true;
}
mtx.unlock();
}
//***********************************************************************
// QWaitCondition implementation
//***********************************************************************
QWaitCondition::QWaitCondition()
{
d = new QWaitConditionPrivate;
}
QWaitCondition::~QWaitCondition()
{
if (!d->queue.isEmpty()) {
qWarning("QWaitCondition: Destroyed while threads are still waiting");
qDeleteAll(d->queue);
}
qDeleteAll(d->freeQueue);
delete d;
}
bool QWaitCondition::wait(QMutex *mutex, unsigned long time)
{
if (!mutex)
return false;
if (mutex->d->recursive) {
qWarning("QWaitCondition::wait: Cannot wait on recursive mutexes");
return false;
}
QWaitConditionEvent *wce = d->pre();
mutex->unlock();
bool returnValue = d->wait(wce, time);
mutex->lock();
d->post(wce, returnValue);
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;
}
QWaitConditionEvent *wce = d->pre();
int previousAccessCount = readWriteLock->d->accessCount;
readWriteLock->unlock();
bool returnValue = d->wait(wce, time);
if (previousAccessCount < 0)
readWriteLock->lockForWrite();
else
readWriteLock->lockForRead();
d->post(wce, returnValue);
return returnValue;
}
void QWaitCondition::wakeOne()
{
// wake up the first waiting thread in the queue
QMutexLocker locker(&d->mtx);
for (int i = 0; i < d->queue.size(); ++i) {
QWaitConditionEvent *current = d->queue.at(i);
if (current->wokenUp)
continue;
SetEvent(current->event);
current->wokenUp = true;
break;
}
}
void QWaitCondition::wakeAll()
{
// wake up the all threads in the queue
QMutexLocker locker(&d->mtx);
for (int i = 0; i < d->queue.size(); ++i) {
QWaitConditionEvent *current = d->queue.at(i);
SetEvent(current->event);
current->wokenUp = true;
}
}
QT_END_NAMESPACE
#endif // QT_NO_THREAD
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