/**************************************************************************** ** ** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). ** 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 "qabstracteventdispatcher.h" #include "qabstracteventdispatcher_p.h" #include "qthread.h" #include #include QT_BEGIN_NAMESPACE // we allow for 2^24 = 8^8 = 16777216 simultaneously running timers enum { NumberOfBuckets = 8, FirstBucketSize = 8 }; static const int BucketSize[NumberOfBuckets] = { 8, 64, 512, 4096, 32768, 262144, 2097152, 16777216 - 2396744 }; static const int BucketOffset[NumberOfBuckets] = { 0, 8, 72, 584, 4680, 37448, 299592, 2396744 }; static int FirstBucket[FirstBucketSize] = { 1, 2, 3, 4, 5, 6, 7, 8 }; static QBasicAtomicPointer timerIds[NumberOfBuckets] = { Q_BASIC_ATOMIC_INITIALIZER(FirstBucket), Q_BASIC_ATOMIC_INITIALIZER(0), Q_BASIC_ATOMIC_INITIALIZER(0), Q_BASIC_ATOMIC_INITIALIZER(0), Q_BASIC_ATOMIC_INITIALIZER(0), Q_BASIC_ATOMIC_INITIALIZER(0), Q_BASIC_ATOMIC_INITIALIZER(0), Q_BASIC_ATOMIC_INITIALIZER(0) }; static void timerIdsDestructorFunction() { // start at one, the first bucket is pre-allocated for (int i = 1; i < NumberOfBuckets; ++i) delete [] static_cast(timerIds[i]); } Q_DESTRUCTOR_FUNCTION(timerIdsDestructorFunction) static QBasicAtomicInt nextFreeTimerId = Q_BASIC_ATOMIC_INITIALIZER(1); // avoid the ABA-problem by using 7 of the top 8 bits of the timerId as a serial number static inline int prepareNewValueWithSerialNumber(int oldId, int newId) { return (newId & 0x00FFFFFF) | ((oldId + 0x01000000) & 0x7f000000); } static inline int bucketOffset(int timerId) { for (int i = 0; i < NumberOfBuckets; ++i) { if (timerId < BucketSize[i]) return i; timerId -= BucketSize[i]; } qFatal("QAbstractEventDispatcher: INTERNAL ERROR, timer ID %d is too large", timerId); return -1; } static inline int bucketIndex(int bucket, int timerId) { return timerId - BucketOffset[bucket]; } static inline int *allocateBucket(int bucket) { // allocate a new bucket const int size = BucketSize[bucket]; const int offset = BucketOffset[bucket]; int *b = new int[size]; for (int i = 0; i != size; ++i) b[i] = offset + i + 1; return b; } void QAbstractEventDispatcherPrivate::init() { Q_Q(QAbstractEventDispatcher); if (threadData->eventDispatcher != 0) { qWarning("QAbstractEventDispatcher: An event dispatcher has already been created for this thread"); } else { threadData->eventDispatcher = q; } } int QAbstractEventDispatcherPrivate::allocateTimerId() { int timerId, newTimerId; do { timerId = nextFreeTimerId; // which bucket are we looking in? int which = timerId & 0x00ffffff; int bucket = bucketOffset(which); int at = bucketIndex(bucket, which); int *b = timerIds[bucket]; if (!b) { // allocate a new bucket b = allocateBucket(bucket); if (!timerIds[bucket].testAndSetRelease(0, b)) { // another thread won the race to allocate the bucket delete [] b; b = timerIds[bucket]; } } newTimerId = b[at]; } while (!nextFreeTimerId.testAndSetRelaxed(timerId, newTimerId)); return timerId; } void QAbstractEventDispatcherPrivate::releaseTimerId(int timerId) { int which = timerId & 0x00ffffff; int bucket = bucketOffset(which); int at = bucketIndex(bucket, which); int *b = timerIds[bucket]; int freeId, newTimerId; do { freeId = nextFreeTimerId; b[at] = freeId & 0x00ffffff; newTimerId = prepareNewValueWithSerialNumber(freeId, timerId); } while (!nextFreeTimerId.testAndSetRelease(freeId, newTimerId)); } /*! \class QAbstractEventDispatcher \brief The QAbstractEventDispatcher class provides an interface to manage Qt's event queue. \ingroup application \ingroup events An event dispatcher receives events from the window system and other sources. It then sends them to the QCoreApplication or QApplication instance for processing and delivery. QAbstractEventDispatcher provides fine-grained control over event delivery. For simple control of event processing use QCoreApplication::processEvents(). For finer control of the application's event loop, call instance() and call functions on the QAbstractEventDispatcher object that is returned. If you want to use your own instance of QAbstractEventDispatcher or of a QAbstractEventDispatcher subclass, you must create your instance \e before you create the QApplication object. The main event loop is started by calling QCoreApplication::exec(), and stopped by calling QCoreApplication::exit(). Local event loops can be created using QEventLoop. Programs that perform long operations can call processEvents() with a bitwise OR combination of various QEventLoop::ProcessEventsFlag values to control which events should be delivered. QAbstractEventDispatcher also allows the integration of an external event loop with the Qt event loop. For example, the \l{Qt Solutions}{Motif Extension Qt Solution} includes a reimplementation of QAbstractEventDispatcher that merges Qt and Motif events together. \sa QEventLoop, QCoreApplication */ /*! Constructs a new event dispatcher with the given \a parent. */ QAbstractEventDispatcher::QAbstractEventDispatcher(QObject *parent) : QObject(*new QAbstractEventDispatcherPrivate, parent) { Q_D(QAbstractEventDispatcher); d->init(); } /*! \internal */ QAbstractEventDispatcher::QAbstractEventDispatcher(QAbstractEventDispatcherPrivate &dd, QObject *parent) : QObject(dd, parent) { Q_D(QAbstractEventDispatcher); d->init(); } /*! Destroys the event dispatcher. */ QAbstractEventDispatcher::~QAbstractEventDispatcher() { } /*! Returns a pointer to the event dispatcher object for the specified \a thread. If \a thread is zero, the current thread is used. If no event dispatcher exists for the specified thread, this function returns 0. \bold{Note:} If Qt is built without thread support, the \a thread argument is ignored. */ QAbstractEventDispatcher *QAbstractEventDispatcher::instance(QThread *thread) { QThreadData *data = thread ? QThreadData::get2(thread) : QThreadData::current(); return data->eventDispatcher; } /*! \fn bool QAbstractEventDispatcher::processEvents(QEventLoop::ProcessEventsFlags flags) Processes pending events that match \a flags until there are no more events to process. Returns true if an event was processed; otherwise returns false. This function is especially useful if you have a long running operation and want to show its progress without allowing user input; i.e. by using the QEventLoop::ExcludeUserInputEvents flag. If the QEventLoop::WaitForMoreEvents flag is set in \a flags, the behavior of this function is as follows: \list \i If events are available, this function returns after processing them. \i If no events are available, this function will wait until more are available and return after processing newly available events. \endlist If the QEventLoop::WaitForMoreEvents flag is not set in \a flags, and no events are available, this function will return immediately. \bold{Note:} This function does not process events continuously; it returns after all available events are processed. \sa hasPendingEvents() */ /*! \fn bool QAbstractEventDispatcher::hasPendingEvents() Returns true if there is an event waiting; otherwise returns false. */ /*! \fn void QAbstractEventDispatcher::registerSocketNotifier(QSocketNotifier *notifier) Registers \a notifier with the event loop. Subclasses must implement this method to tie a socket notifier into another event loop. */ /*! \fn void QAbstractEventDispatcher::unregisterSocketNotifier(QSocketNotifier *notifier) Unregisters \a notifier from the event dispatcher. Subclasses must reimplement this method to tie a socket notifier into another event loop. Reimplementations must call the base implementation. */ /*! \fn int QAbstractEventDispatcher::registerTimer(int interval, QObject *object) Registers a timer with the specified \a interval for the given \a object. */ int QAbstractEventDispatcher::registerTimer(int interval, QObject *object) { int id = QAbstractEventDispatcherPrivate::allocateTimerId(); registerTimer(id, interval, object); return id; } /*! \fn void QAbstractEventDispatcher::registerTimer(int timerId, int interval, QObject *object) Register a timer with the specified \a timerId and \a interval for the given \a object. */ /*! \fn bool QAbstractEventDispatcher::unregisterTimer(int timerId) Unregisters the timer with the given \a timerId. Returns true if successful; otherwise returns false. \sa registerTimer(), unregisterTimers() */ /*! \fn bool QAbstractEventDispatcher::unregisterTimers(QObject *object) Unregisters all the timers associated with the given \a object. Returns true if all timers were successful removed; otherwise returns false. \sa unregisterTimer(), registeredTimers() */ /*! \fn QList QAbstractEventDispatcher::registeredTimers(QObject *object) const Returns a list of registered timers for \a object. The timer ID is the first member in each pair; the interval is the second. */ /*! \fn void QAbstractEventDispatcher::wakeUp() \threadsafe Wakes up the event loop. \sa awake() */ /*! \fn void QAbstractEventDispatcher::interrupt() Interrupts event dispatching; i.e. the event dispatcher will return from processEvents() as soon as possible. */ /*! \fn void QAbstractEventDispatcher::flush() Flushes the event queue. This normally returns almost immediately. Does nothing on platforms other than X11. */ // ### DOC: Are these called when the _application_ starts/stops or just // when the current _event loop_ starts/stops? /*! \internal */ void QAbstractEventDispatcher::startingUp() { } /*! \internal */ void QAbstractEventDispatcher::closingDown() { } /*! \typedef QAbstractEventDispatcher::TimerInfo Typedef for QPair. The first component of the pair is the timer ID; the second component is the interval. \sa registeredTimers() */ /*! \typedef QAbstractEventDispatcher::EventFilter Typedef for a function with the signature \snippet doc/src/snippets/code/src_corelib_kernel_qabstracteventdispatcher.cpp 0 \sa setEventFilter(), filterEvent() */ /*! Sets the event filter \a filter. Returns a pointer to the filter function previously defined. The event filter is a function that receives all messages taken from the system event loop before the event is dispatched to the respective target. This includes messages that are not sent to Qt objects. The function can return true to stop the event to be processed by Qt, or false to continue with the standard event processing. Only one filter can be defined, but the filter can use the return value to call the previously set event filter. By default, no filter is set (i.e. the function returns 0). */ QAbstractEventDispatcher::EventFilter QAbstractEventDispatcher::setEventFilter(EventFilter filter) { Q_D(QAbstractEventDispatcher); EventFilter oldFilter = d->event_filter; d->event_filter = filter; return oldFilter; } /*! Sends \a message through the event filter that was set by setEventFilter(). If no event filter has been set, this function returns false; otherwise, this function returns the result of the event filter function. Subclasses of QAbstractEventDispatcher \e must call this function for \e all messages received from the system to ensure compatibility with any extensions that may be used in the application. \sa setEventFilter() */ bool QAbstractEventDispatcher::filterEvent(void *message) { Q_D(QAbstractEventDispatcher); if (d->event_filter) return d->event_filter(message); return false; } /*! \fn void QAbstractEventDispatcher::awake() This signal is emitted after the event loop returns from a function that could block. \sa wakeUp() aboutToBlock() */ /*! \fn void QAbstractEventDispatcher::aboutToBlock() This signal is emitted before the event loop calls a function that could block. \sa awake() */ QT_END_NAMESPACE