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// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
// Qt-Security score:significant reason:default
#include "qwaitcondition.h"
#include "qdeadlinetimer.h"
#include "qnamespace.h"
#include "qmutex.h"
#include "qreadwritelock.h"
#include "qlist.h"
#include "qalgorithms.h"
#define Q_MUTEX_T void *
#include <private/qmutex_p.h>
#include <private/qreadwritelock_p.h>
#include <qt_windows.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, QDeadlineTimer deadline);
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, QDeadlineTimer deadline)
{
// wait for the event
while (true) {
const DWORD timeout = deadline.isForever()
? INFINITE
: DWORD(std::min(deadline.remainingTime(), qint64(INFINITE - 1)));
switch (WaitForSingleObjectEx(wce->event, timeout, FALSE)) {
case WAIT_OBJECT_0:
return true;
case WAIT_TIMEOUT:
if (deadline.hasExpired())
return false;
break;
default:
return false;
}
}
}
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.constFirst();
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 (time == std::numeric_limits<unsigned long>::max())
return wait(mutex, QDeadlineTimer(QDeadlineTimer::Forever));
return wait(mutex, QDeadlineTimer(time));
}
bool QWaitCondition::wait(QMutex *mutex, QDeadlineTimer deadline)
{
if (!mutex)
return false;
QWaitConditionEvent *wce = d->pre();
mutex->unlock();
bool returnValue = d->wait(wce, deadline);
mutex->lock();
d->post(wce, returnValue);
return returnValue;
}
bool QWaitCondition::wait(QReadWriteLock *readWriteLock, unsigned long time)
{
if (time == std::numeric_limits<unsigned long>::max())
return wait(readWriteLock, QDeadlineTimer(QDeadlineTimer::Forever));
return wait(readWriteLock, QDeadlineTimer(time));
}
bool QWaitCondition::wait(QReadWriteLock *readWriteLock, QDeadlineTimer deadline)
{
QWaitConditionEvent *wce = nullptr;
auto prep = [&] { wce = d->pre(); };
auto wait = [&] { return d->wait(wce, deadline); };
bool returnValue = QReadWriteLockPrivate::waitConditionWait(readWriteLock, prep, wait);
if (wce)
d->post(wce, returnValue);
return returnValue;
}
void QWaitCondition::wakeOne()
{
// wake up the first waiting thread in the queue
QMutexLocker locker(&d->mtx);
for (QWaitConditionEvent *current : std::as_const(d->queue)) {
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 (QWaitConditionEvent *current : std::as_const(d->queue)) {
SetEvent(current->event);
current->wokenUp = true;
}
}
QT_END_NAMESPACE