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/****************************************************************************
**
** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** 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 Technology Preview License Agreement accompanying
** this package.
**
** 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 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** If you have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
**
**
**
**
**
**
**
**
** $QT_END_LICENSE$
**
****************************************************************************/
#include "qplatformdefs.h"
#include "qwaitcondition.h"
#include "qmutex.h"
#include "qreadwritelock.h"
#include "qatomic.h"
#include "qstring.h"
#include "qelapsedtimer.h"
#include "qmutex_p.h"
#include "qreadwritelock_p.h"
#ifndef QT_NO_THREAD
QT_BEGIN_NAMESPACE
static void report_error(int err, const char *where, const char *what)
{
if (err != KErrNone)
qWarning("%s: %s failure: %d", where, what, err);
}
class QWaitConditionPrivate {
public:
RMutex mutex;
RCondVar cond;
int waiters;
int wakeups;
QWaitConditionPrivate()
: waiters(0), wakeups(0)
{
qt_symbian_throwIfError(mutex.CreateLocal());
int err = cond.CreateLocal();
if (err != KErrNone) {
mutex.Close();
qt_symbian_throwIfError(err);
}
}
~QWaitConditionPrivate()
{
cond.Close();
mutex.Close();
}
bool wait(unsigned long time)
{
TInt err = KErrNone;
if (time == ULONG_MAX) {
// untimed wait, loop because RCondVar::Wait may return before the condition is triggered
do {
err = cond.Wait(mutex);
} while (err == KErrNone && wakeups == 0);
} else {
unsigned long maxWait = KMaxTInt / 1000;
QElapsedTimer waitTimer;
do {
waitTimer.start();
unsigned long waitTime = qMin(maxWait, time);
// wait at least 1ms, as 0 means no wait
err = cond.TimedWait(mutex, qMax(1ul, waitTime) * 1000);
// RCondVar::TimedWait may return before the condition is triggered, update the timeout with actual wait time
time -= qMin((unsigned long)waitTimer.elapsed(), waitTime);
} while ((err == KErrNone && wakeups == 0) || (err == KErrTimedOut && time > 0));
}
Q_ASSERT_X(waiters > 0, "QWaitCondition::wait", "internal error (waiters)");
--waiters;
if (err == KErrNone) {
Q_ASSERT_X(wakeups > 0, "QWaitCondition::wait", "internal error (wakeups)");
--wakeups;
}
mutex.Signal();
if (err && err != KErrTimedOut)
report_error(err, "QWaitCondition::wait()", "cv wait");
return err == KErrNone;
}
};
QWaitCondition::QWaitCondition()
{
d = new QWaitConditionPrivate;
}
QWaitCondition::~QWaitCondition()
{
delete d;
}
void QWaitCondition::wakeOne()
{
d->mutex.Wait();
d->wakeups = qMin(d->wakeups + 1, d->waiters);
d->cond.Signal();
d->mutex.Signal();
}
void QWaitCondition::wakeAll()
{
d->mutex.Wait();
d->wakeups = d->waiters;
d->cond.Broadcast();
d->mutex.Signal();
}
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;
}
d->mutex.Wait();
++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;
}
d->mutex.Wait();
++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
|
