qabstracteventdispatcher.cpp

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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
 
#include "qabstracteventdispatcher.h"
#include "qabstracteventdispatcher_p.h"
#include "qabstractnativeeventfilter.h"
 
#include "qthread.h"
#include <private/qthread_p.h>
#include <private/qcoreapplication_p.h>
#include <private/qfreelist_p.h>
 
QT_BEGIN_NAMESPACE
 
// we allow for 2^24 = 8^8 = 16777216 simultaneously running timers
struct QtTimerIdFreeListConstants : public QFreeListDefaultConstants
{
    enum
    {
        InitialNextValue = 1,
        BlockCount = 6
    };
 
    static const int Sizes[BlockCount];
};
 
enum {
    Offset0 = 0x00000000,
    Offset1 = 0x00000040,
    Offset2 = 0x00000100,
    Offset3 = 0x00001000,
    Offset4 = 0x00010000,
    Offset5 = 0x00100000,
 
    Size0 = Offset1 - Offset0,
    Size1 = Offset2 - Offset1,
    Size2 = Offset3 - Offset2,
    Size3 = Offset4 - Offset3,
    Size4 = Offset5 - Offset4,
    Size5 = QtTimerIdFreeListConstants::MaxIndex - Offset5
};
 
Q_CONSTINIT const int QtTimerIdFreeListConstants::Sizes[QtTimerIdFreeListConstants::BlockCount] = {
    Size0,
    Size1,
    Size2,
    Size3,
    Size4,
    Size5
};
 
typedef QFreeList<void, QtTimerIdFreeListConstants> QtTimerIdFreeList;
Q_GLOBAL_STATIC(QtTimerIdFreeList, timerIdFreeList)
 
QAbstractEventDispatcherPrivate::~QAbstractEventDispatcherPrivate()
    = default;
 
int QAbstractEventDispatcherPrivate::allocateTimerId()
{
    // This function may be called after timerIdFreeList() has been destructed
    // for example in case when application exits without waiting for
    // running threads to exit and running thread finished() has been connected
    // to a slot which triggers a sequence that registers new timer.
    // See https://bugreports.qt-project.org/browse/QTBUG-38957.
    if (QtTimerIdFreeList *fl = timerIdFreeList())
        return fl->next();
    return 0; // Note! returning 0 generates a warning
}
 
void QAbstractEventDispatcherPrivate::releaseTimerId(int timerId)
{
    // this function may be called by a global destructor after
    // timerIdFreeList() has been destructed
    if (QtTimerIdFreeList *fl = timerIdFreeList())
        fl->release(timerId);
}
 
QAbstractEventDispatcher::QAbstractEventDispatcher(QObject *parent)
    : QObject(*new QAbstractEventDispatcherPrivate, parent) {}
 
QAbstractEventDispatcher::QAbstractEventDispatcher(QAbstractEventDispatcherPrivate &dd,
                                                   QObject *parent)
    : QObject(dd, parent) {}
 
QAbstractEventDispatcher::~QAbstractEventDispatcher()
{ }
 
QAbstractEventDispatcher *QAbstractEventDispatcher::instance(QThread *thread)
{
    QThreadData *data = thread ? QThreadData::get2(thread) : QThreadData::current();
    return data->eventDispatcher.loadRelaxed();
}
 
int QAbstractEventDispatcher::registerTimer(qint64 interval, Qt::TimerType timerType, QObject *object)
{
    int id = QAbstractEventDispatcherPrivate::allocateTimerId();
    registerTimer(id, interval, timerType, object);
    return id;
}
 
// ### DOC: Are these called when the _application_ starts/stops or just
// when the current _event loop_ starts/stops?
void QAbstractEventDispatcher::startingUp()
{ }
 
void QAbstractEventDispatcher::closingDown()
{ }
 
void QAbstractEventDispatcher::installNativeEventFilter(QAbstractNativeEventFilter *filterObj)
{
    Q_D(QAbstractEventDispatcher);
 
    // clean up unused items in the list
    d->eventFilters.removeAll(nullptr);
    d->eventFilters.removeAll(filterObj);
    d->eventFilters.prepend(filterObj);
}
 
void QAbstractEventDispatcher::removeNativeEventFilter(QAbstractNativeEventFilter *filter)
{
    Q_D(QAbstractEventDispatcher);
    for (int i = 0; i < d->eventFilters.size(); ++i) {
        if (d->eventFilters.at(i) == filter) {
            d->eventFilters[i] = nullptr;
            break;
        }
    }
}
 
bool QAbstractEventDispatcher::filterNativeEvent(const QByteArray &eventType, void *message, qintptr *result)
{
    Q_D(QAbstractEventDispatcher);
    if (!d->eventFilters.isEmpty()) {
        // Raise the loopLevel so that deleteLater() calls in or triggered
        // by event_filter() will be processed from the main event loop.
        QScopedScopeLevelCounter scopeLevelCounter(d->threadData.loadAcquire());
        for (int i = 0; i < d->eventFilters.size(); ++i) {
            QAbstractNativeEventFilter *filter = d->eventFilters.at(i);
            if (!filter)
                continue;
            if (filter->nativeEventFilter(eventType, message, result))
                return true;
        }
    }
    return false;
}
 
QT_END_NAMESPACE
 
#include "moc_qabstracteventdispatcher.cpp"