/****************************************************************************
**
** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the QtGui module of the Qt Toolkit.
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** 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.
**
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** Nokia at qt-info@nokia.com.
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** $QT_END_LICENSE$
**
****************************************************************************/

/****************************************************************************
**
** Copyright (c) 2007-2008, Apple, Inc.
**
** All rights reserved.
**
** Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions are met:
**
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**     this list of conditions and the following disclaimer.
**
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**
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**     may be used to endorse or promote products derived from this software
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** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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****************************************************************************/

#include "qplatformdefs.h"
#include "private/qt_mac_p.h"
#include "qeventdispatcher_mac_p.h"
#include "qapplication.h"
#include "qevent.h"
#include "qdialog.h"
#include "qhash.h"
#include "qsocketnotifier.h"
#include "private/qwidget_p.h"
#include "private/qthread_p.h"
#include "private/qapplication_p.h"

#include <private/qcocoaapplication_mac_p.h>
#include "private/qt_cocoa_helpers_mac_p.h"

#ifndef QT_NO_THREAD
#  include "qmutex.h"

QT_BEGIN_NAMESPACE

QT_USE_NAMESPACE
#endif

/*****************************************************************************
  Externals
 *****************************************************************************/
extern void qt_event_request_timer(MacTimerInfo *); //qapplication_mac.cpp
extern MacTimerInfo *qt_event_get_timer(EventRef); //qapplication_mac.cpp
extern void qt_event_request_select(QEventDispatcherMac *); //qapplication_mac.cpp
extern void qt_event_request_updates(); //qapplication_mac.cpp
extern OSWindowRef qt_mac_window_for(const QWidget *); //qwidget_mac.cpp
extern bool qt_is_gui_used; //qapplication.cpp
extern bool qt_sendSpontaneousEvent(QObject*, QEvent*); // qapplication.cpp
extern bool qt_mac_is_macsheet(const QWidget *); //qwidget_mac.cpp

static inline CFRunLoopRef mainRunLoop()
{
#ifndef QT_MAC_USE_COCOA
    return reinterpret_cast<CFRunLoopRef>(const_cast<void *>(GetCFRunLoopFromEventLoop(GetMainEventLoop())));
#else
    return CFRunLoopGetMain();
#endif
}

/*****************************************************************************
  Timers stuff
 *****************************************************************************/

/* timer call back */
void QEventDispatcherMacPrivate::activateTimer(CFRunLoopTimerRef, void *info)
{
    int timerID =
#ifdef Q_OS_MAC64
    qint64(info);
#else
    int(info);
#endif

    MacTimerInfo *tmr;
    tmr = macTimerHash.value(timerID);
    if (tmr == 0 || tmr->pending == true)
        return; // Can't send another timer event if it's pending.


    if (blockSendPostedEvents) {
        QCoreApplication::postEvent(tmr->obj, new QTimerEvent(tmr->id));
    } else {
        tmr->pending = true;
        QTimerEvent e(tmr->id);
        qt_sendSpontaneousEvent(tmr->obj, &e);
        // Get the value again in case the timer gets unregistered during the sendEvent.
        tmr = macTimerHash.value(timerID);
        if (tmr != 0)
            tmr->pending = false;
    }

}

void QEventDispatcherMac::registerTimer(int timerId, int interval, QObject *obj)
{
#ifndef QT_NO_DEBUG
    if (timerId < 1 || interval < 0 || !obj) {
        qWarning("QEventDispatcherMac::registerTimer: invalid arguments");
        return;
    } else if (obj->thread() != thread() || thread() != QThread::currentThread()) {
        qWarning("QObject::startTimer: timers cannot be started from another thread");
        return;
    }
#endif

    MacTimerInfo *t = new MacTimerInfo();
    t->id = timerId;
    t->interval = interval;
    t->obj = obj;
    t->runLoopTimer = 0;
    t->pending = false;

    CFAbsoluteTime fireDate = CFAbsoluteTimeGetCurrent();
    CFTimeInterval cfinterval = qMax(CFTimeInterval(interval) / 1000, 0.0000001);
    fireDate += cfinterval;
    QEventDispatcherMacPrivate::macTimerHash.insert(timerId, t);
    CFRunLoopTimerContext info = { 0, (void *)timerId, 0, 0, 0 };
    t->runLoopTimer = CFRunLoopTimerCreate(0, fireDate, cfinterval, 0, 0,
                                           QEventDispatcherMacPrivate::activateTimer, &info);
    if (t->runLoopTimer == 0) {
        qFatal("QEventDispatcherMac::registerTimer: Cannot create timer");
    }
    CFRunLoopAddTimer(mainRunLoop(), t->runLoopTimer, kCFRunLoopCommonModes);
}

bool QEventDispatcherMac::unregisterTimer(int identifier)
{
#ifndef QT_NO_DEBUG
    if (identifier < 1) {
        qWarning("QEventDispatcherMac::unregisterTimer: invalid argument");
        return false;
    } else if (thread() != QThread::currentThread()) {
        qWarning("QObject::killTimer: timers cannot be stopped from another thread");
        return false;
    }
#endif
    if (identifier <= 0)
        return false;                                // not init'd or invalid timer

    MacTimerInfo *timerInfo = QEventDispatcherMacPrivate::macTimerHash.take(identifier);
    if (timerInfo == 0)
        return false;

    if (!QObjectPrivate::get(timerInfo->obj)->inThreadChangeEvent)
        QAbstractEventDispatcherPrivate::releaseTimerId(identifier);
    CFRunLoopTimerInvalidate(timerInfo->runLoopTimer);
    CFRelease(timerInfo->runLoopTimer);
    delete timerInfo;

    return true;
}

bool QEventDispatcherMac::unregisterTimers(QObject *obj)
{
#ifndef QT_NO_DEBUG
    if (!obj) {
        qWarning("QEventDispatcherMac::unregisterTimers: invalid argument");
        return false;
    } else if (obj->thread() != thread() || thread() != QThread::currentThread()) {
        qWarning("QObject::killTimers: timers cannot be stopped from another thread");
        return false;
    }
#endif

    MacTimerHash::iterator it = QEventDispatcherMacPrivate::macTimerHash.begin();
    while (it != QEventDispatcherMacPrivate::macTimerHash.end()) {
        MacTimerInfo *timerInfo = it.value();
        if (timerInfo->obj != obj) {
            ++it;
        } else {
            if (!QObjectPrivate::get(timerInfo->obj)->inThreadChangeEvent)
                QAbstractEventDispatcherPrivate::releaseTimerId(timerInfo->id);
            CFRunLoopTimerInvalidate(timerInfo->runLoopTimer);
            CFRelease(timerInfo->runLoopTimer);
            delete timerInfo;
            it = QEventDispatcherMacPrivate::macTimerHash.erase(it);
        }
    }
    return true;
}

QList<QEventDispatcherMac::TimerInfo>
QEventDispatcherMac::registeredTimers(QObject *object) const
{
    if (!object) {
        qWarning("QEventDispatcherMac:registeredTimers: invalid argument");
        return QList<TimerInfo>();
    }

    QList<TimerInfo> list;

    MacTimerHash::const_iterator it = QEventDispatcherMacPrivate::macTimerHash.constBegin();
    while (it != QEventDispatcherMacPrivate::macTimerHash.constEnd()) {
        MacTimerInfo *t = it.value();
        if (t->obj == object)
            list << TimerInfo(t->id, t->interval);
        ++it;
    }
    return list;
}

/**************************************************************************
    Socket Notifiers
 *************************************************************************/
void qt_mac_socket_callback(CFSocketRef s, CFSocketCallBackType callbackType, CFDataRef,
                            const void *,  void *info) {
    QEventDispatcherMacPrivate *const eventDispatcher
                                    = static_cast<QEventDispatcherMacPrivate *>(info);
    int nativeSocket = CFSocketGetNative(s);
    MacSocketInfo *socketInfo = eventDispatcher->macSockets.value(nativeSocket);
    QEvent notifierEvent(QEvent::SockAct);

    // There is a race condition that happen where we disable the notifier and
    // the kernel still has a notification to pass on. We then get this
    // notification after we've successfully disabled the CFSocket, but our Qt
    // notifier is now gone. The upshot is we have to check the notifier
    // everytime.
    if (callbackType == kCFSocketReadCallBack) {
        if (socketInfo->readNotifier)
            QApplication::sendEvent(socketInfo->readNotifier, &notifierEvent);
    } else if (callbackType == kCFSocketWriteCallBack) {
        if (socketInfo->writeNotifier)
            QApplication::sendEvent(socketInfo->writeNotifier, &notifierEvent);
    }
}

/*
    Adds a loop source for the given socket to the current run loop.
*/
CFRunLoopSourceRef qt_mac_add_socket_to_runloop(const CFSocketRef socket)
{
    CFRunLoopSourceRef loopSource = CFSocketCreateRunLoopSource(kCFAllocatorDefault, socket, 0);
    if (!loopSource)
        return 0;

    CFRunLoopAddSource(mainRunLoop(), loopSource, kCFRunLoopCommonModes);
    return loopSource;
}

/*
    Removes the loop source for the given socket from the current run loop.
*/
void qt_mac_remove_socket_from_runloop(const CFSocketRef socket, CFRunLoopSourceRef runloop)
{
    Q_ASSERT(runloop);
    CFRunLoopRemoveSource(mainRunLoop(), runloop, kCFRunLoopCommonModes);
    CFSocketDisableCallBacks(socket, kCFSocketReadCallBack);
    CFSocketDisableCallBacks(socket, kCFSocketWriteCallBack);
    CFRunLoopSourceInvalidate(runloop);
}

/*
    Register a QSocketNotifier with the mac event system by creating a CFSocket with
    with a read/write callback.

    Qt has separate socket notifiers for reading and writing, but on the mac there is
    a limitation of one CFSocket object for each native socket.
*/
void QEventDispatcherMac::registerSocketNotifier(QSocketNotifier *notifier)
{
    Q_ASSERT(notifier);
    int nativeSocket = notifier->socket();
    int type = notifier->type();
#ifndef QT_NO_DEBUG
    if (nativeSocket < 0 || nativeSocket > FD_SETSIZE) {
        qWarning("QSocketNotifier: Internal error");
        return;
    } else if (notifier->thread() != thread()
               || thread() != QThread::currentThread()) {
        qWarning("QSocketNotifier: socket notifiers cannot be enabled from another thread");
        return;
    }
#endif

    Q_D(QEventDispatcherMac);

    if (type == QSocketNotifier::Exception) {
        qWarning("QSocketNotifier::Exception is not supported on Mac OS X");
        return;
    }

    // Check if we have a CFSocket for the native socket, create one if not.
    MacSocketInfo *socketInfo = d->macSockets.value(nativeSocket);
    if (!socketInfo) {
        socketInfo = new MacSocketInfo();

        // Create CFSocket, specify that we want both read and write callbacks (the callbacks
        // are enabled/disabled later on).
        const int callbackTypes = kCFSocketReadCallBack | kCFSocketWriteCallBack;
        CFSocketContext context = {0, d, 0, 0, 0};
        socketInfo->socket = CFSocketCreateWithNative(kCFAllocatorDefault, nativeSocket, callbackTypes, qt_mac_socket_callback, &context);
        if (CFSocketIsValid(socketInfo->socket) == false) {
            qWarning("QEventDispatcherMac::registerSocketNotifier: Failed to create CFSocket");
            return;
        }

        CFOptionFlags flags = CFSocketGetSocketFlags(socketInfo->socket);
        flags |= kCFSocketAutomaticallyReenableWriteCallBack; //QSocketNotifier stays enabled after a write
        flags &= ~kCFSocketCloseOnInvalidate; //QSocketNotifier doesn't close the socket upon destruction/invalidation
        CFSocketSetSocketFlags(socketInfo->socket, flags);

        // Add CFSocket to runloop.
        if(!(socketInfo->runloop = qt_mac_add_socket_to_runloop(socketInfo->socket))) {
            qWarning("QEventDispatcherMac::registerSocketNotifier: Failed to add CFSocket to runloop");
            CFSocketInvalidate(socketInfo->socket);
            CFRelease(socketInfo->socket);
            return;
        }

        // Disable both callback types by default. This must be done after
        // we add the CFSocket to the runloop, or else these calls will have
        // no effect.
        CFSocketDisableCallBacks(socketInfo->socket, kCFSocketReadCallBack);
        CFSocketDisableCallBacks(socketInfo->socket, kCFSocketWriteCallBack);

        d->macSockets.insert(nativeSocket, socketInfo);
    }

    // Increment read/write counters and select enable callbacks if necessary.
    if (type == QSocketNotifier::Read) {
        Q_ASSERT(socketInfo->readNotifier == 0);
        socketInfo->readNotifier = notifier;
        CFSocketEnableCallBacks(socketInfo->socket, kCFSocketReadCallBack);
    } else if (type == QSocketNotifier::Write) {
        Q_ASSERT(socketInfo->writeNotifier == 0);
        socketInfo->writeNotifier = notifier;
        CFSocketEnableCallBacks(socketInfo->socket, kCFSocketWriteCallBack);
    }
}

/*
    Unregister QSocketNotifer. The CFSocket correspoding to this notifier is
    removed from the runloop of this is the last notifier that users
    that CFSocket.
*/
void QEventDispatcherMac::unregisterSocketNotifier(QSocketNotifier *notifier)
{
    Q_ASSERT(notifier);
    int nativeSocket = notifier->socket();
    int type = notifier->type();
#ifndef QT_NO_DEBUG
    if (nativeSocket < 0 || nativeSocket > FD_SETSIZE) {
        qWarning("QSocketNotifier: Internal error");
        return;
    } else if (notifier->thread() != thread() || thread() != QThread::currentThread()) {
        qWarning("QSocketNotifier: socket notifiers cannot be disabled from another thread");
        return;
    }
#endif

    Q_D(QEventDispatcherMac);

    if (type == QSocketNotifier::Exception) {
        qWarning("QSocketNotifier::Exception is not supported on Mac OS X");
        return;
    }
    MacSocketInfo *socketInfo = d->macSockets.value(nativeSocket);
    if (!socketInfo) {
        qWarning("QEventDispatcherMac::unregisterSocketNotifier: Tried to unregister a not registered notifier");
        return;
    }

    // Decrement read/write counters and disable callbacks if necessary.
    if (type == QSocketNotifier::Read) {
        Q_ASSERT(notifier == socketInfo->readNotifier);
        socketInfo->readNotifier = 0;
        CFSocketDisableCallBacks(socketInfo->socket, kCFSocketReadCallBack);
    } else if (type == QSocketNotifier::Write) {
        Q_ASSERT(notifier == socketInfo->writeNotifier);
        socketInfo->writeNotifier = 0;
        CFSocketDisableCallBacks(socketInfo->socket, kCFSocketWriteCallBack);
    }

    // Remove CFSocket from runloop if this was the last QSocketNotifier.
    if (socketInfo->readNotifier == 0 && socketInfo->writeNotifier == 0) {
        if (CFSocketIsValid(socketInfo->socket))
            qt_mac_remove_socket_from_runloop(socketInfo->socket, socketInfo->runloop);
        CFRunLoopSourceInvalidate(socketInfo->runloop);
        CFRelease(socketInfo->runloop);
        CFSocketInvalidate(socketInfo->socket);
        CFRelease(socketInfo->socket);
        delete socketInfo;
        d->macSockets.remove(nativeSocket);
    }
}

bool QEventDispatcherMac::hasPendingEvents()
{
    extern uint qGlobalPostedEventsCount();
    return qGlobalPostedEventsCount() || (qt_is_gui_used && GetNumEventsInQueue(GetMainEventQueue()));
}


static bool qt_mac_send_event(QEventLoop::ProcessEventsFlags, OSEventRef event, OSWindowRef pt)
{
#ifndef QT_MAC_USE_COCOA
    if(pt && SendEventToWindow(event, pt) != eventNotHandledErr)
        return true;
    return !SendEventToEventTarget(event, GetEventDispatcherTarget());
#else // QT_MAC_USE_COCOA
    if (pt)
        [pt sendEvent:event];
    else
        [NSApp sendEvent:event];
    return true;
#endif
}

#ifdef QT_MAC_USE_COCOA
static bool IsMouseOrKeyEvent( NSEvent* event )
{
    bool    result    = false;
    
    switch( [event type] )
    {
        case NSLeftMouseDown:              
        case NSLeftMouseUp:      
        case NSRightMouseDown:   
        case NSRightMouseUp:     
        case NSMouseMoved:                // ??
        case NSLeftMouseDragged: 
        case NSRightMouseDragged:
        case NSMouseEntered:     
        case NSMouseExited:      
        case NSKeyDown:          
        case NSKeyUp:            
        case NSFlagsChanged:            // key modifiers changed?
        case NSCursorUpdate:            // ??
        case NSScrollWheel:      
        case NSTabletPoint:      
        case NSTabletProximity:  
        case NSOtherMouseDown:   
        case NSOtherMouseUp:     
        case NSOtherMouseDragged:
            result    = true;
        break;

        default:
        break;
    }
    return result;
}
#endif

static inline void qt_mac_waitForMoreEvents()
{
#ifndef QT_MAC_USE_COCOA
    while (CFRunLoopRunInMode(kCFRunLoopDefaultMode, 1.0e20, true) == kCFRunLoopRunTimedOut) ;
#else
    // If no event exist in the cocoa event que, wait
    // (and free up cpu time) until at least one event occur.
    // This implementation is a bit on the edge, but seems to
    // work fine:
    NSEvent* event = [NSApp nextEventMatchingMask:NSAnyEventMask
        untilDate:[NSDate distantFuture]
        inMode:NSDefaultRunLoopMode
        dequeue:YES];
    if (event)
        [NSApp postEvent:event atStart:YES];
#endif
}

#ifdef QT_MAC_USE_COCOA
static inline void qt_mac_waitForMoreModalSessionEvents()
{
    // If no event exist in the cocoa event que, wait
    // (and free up cpu time) until at least one event occur.
    // This implementation is a bit on the edge, but seems to
    // work fine:
    NSEvent* event = [NSApp nextEventMatchingMask:NSAnyEventMask
        untilDate:[NSDate distantFuture]
        inMode:NSModalPanelRunLoopMode
        dequeue:YES];
    if (event)
        [NSApp postEvent:event atStart:YES];
}
#endif

bool QEventDispatcherMac::processEvents(QEventLoop::ProcessEventsFlags flags)
{
    Q_D(QEventDispatcherMac);
    d->interrupt = false;
    // In case we end up recursing while we now process events, make sure
    // that we send remaining posted Qt events before this call returns:
    wakeUp();
    emit awake();

    bool retVal = false;
    forever {
        if (d->interrupt)
            break;

#ifdef QT_MAC_USE_COCOA
        QMacCocoaAutoReleasePool pool;
        NSEvent* event = 0;

        // If Qt is used as a plugin, or just added into a native cocoa
        // application, we should not run or stop NSApplication;
        // This will be done from outside Qt.
        // And if processEvents is called manually (rather than from QEventLoop), we
        // cannot enter a tight loop and block the call, but instead return after one flush:
        bool canExec_3rdParty = d->nsAppRunCalledByQt || ![NSApp isRunning];
        bool canExec_Qt = flags & QEventLoop::DialogExec || flags & QEventLoop::EventLoopExec;

        if (canExec_Qt && canExec_3rdParty) {
            // We can use exec-mode, meaning that we can stay in a tight loop until
            // interrupted. This is mostly an optimization, but it also allow us
            // to use [NSApp run], which is the recommended way of running applications
            // in cocoa. [NSApp run] should be called at least once for any cocoa app.
            if (NSModalSession session = d->currentModalSession()) {
                QBoolBlocker execGuard(d->currentExecIsNSAppRun, false);
                while (!d->interrupt && [NSApp runModalSession:session] == NSRunContinuesResponse)
                    qt_mac_waitForMoreModalSessionEvents();
                if (!d->interrupt && session == d->currentModalSessionCached) {
                    // INVARIANT: Someone called e.g. [NSApp stopModal:] from outside the event
                    // dispatcher (e.g to stop a native dialog). But that call wrongly stopped
                    // 'session' as well. As a result, we need to restart all internal sessions:
                    d->temporarilyStopAllModalSessions();
                }
            } else {
                d->nsAppRunCalledByQt = true;
                QBoolBlocker execGuard(d->currentExecIsNSAppRun, true);
                [NSApp run];
            }
            retVal = true;
        } else do {
            // INVARIANT: We cannot block the thread (and run in a tight loop).
            // Instead we will process all current pending events and return.
            bool mustRelease = false;

            if (!(flags & QEventLoop::ExcludeUserInputEvents) && !d->queuedUserInputEvents.isEmpty()) {
                // Process a pending user input event
                mustRelease = true;
                event = static_cast<NSEvent *>(d->queuedUserInputEvents.takeFirst());
            } else {
                if (NSModalSession session = d->currentModalSession()) {
                    if (flags & QEventLoop::WaitForMoreEvents)
                        qt_mac_waitForMoreModalSessionEvents();
                    NSInteger status = [NSApp runModalSession:session];
                    if (status != NSRunContinuesResponse && session == d->currentModalSessionCached) {
                        // INVARIANT: Someone called e.g. [NSApp stopModal:] from outside the event
                        // dispatcher (e.g to stop a native dialog). But that call wrongly stopped
                        // 'session' as well. As a result, we need to restart all internal sessions:
                        d->temporarilyStopAllModalSessions();
                    }
                    retVal = true;
                    break;
                } else {
                    event = [NSApp nextEventMatchingMask:NSAnyEventMask
                        untilDate:nil
                        inMode:NSDefaultRunLoopMode
                        dequeue: YES];

                    if (event != nil) {
                        if (flags & QEventLoop::ExcludeUserInputEvents) {
                            if (IsMouseOrKeyEvent(event)) {
                                // retain event here?
                                [event retain];
                                d->queuedUserInputEvents.append(event);
                                continue;
                            }
                        }
                    }
                }
            }
            if (event) {
                if (!filterEvent(event) && qt_mac_send_event(flags, event, 0))
                    retVal = true;
                if (mustRelease)
                    [event release];
            }
        } while(!d->interrupt && event != nil);

#else
        do {
            EventRef event;
            if (!(flags & QEventLoop::ExcludeUserInputEvents)
                    && !d->queuedUserInputEvents.isEmpty()) {
                // process a pending user input event
                event = static_cast<EventRef>(d->queuedUserInputEvents.takeFirst());
            } else {
                OSStatus err = ReceiveNextEvent(0,0, kEventDurationNoWait, true, &event);
                if(err != noErr)
                    continue;
                // else
                if (flags & QEventLoop::ExcludeUserInputEvents) {
                    UInt32 ekind = GetEventKind(event),
                           eclass = GetEventClass(event);
                    switch(eclass) {
                        case kEventClassQt:
                            if(ekind != kEventQtRequestContext)
                                break;
                            // fall through
                        case kEventClassMouse:
                        case kEventClassKeyboard:
                            d->queuedUserInputEvents.append(event);
                            continue;
                    }
                }
            }

            if (!filterEvent(&event) && qt_mac_send_event(flags, event, 0))
                retVal = true;
            ReleaseEvent(event);
        } while(!d->interrupt && GetNumEventsInQueue(GetMainEventQueue()) > 0);

#endif

        bool canWait = (d->threadData->canWait
                && !retVal
                && !d->interrupt
                && (flags & QEventLoop::WaitForMoreEvents));
        if (canWait) {
            // INVARIANT: We haven't processed any events yet. And we're told
            // to stay inside this function until at least one event is processed.
            qt_mac_waitForMoreEvents();
            flags &= ~QEventLoop::WaitForMoreEvents;
        } else {
            // Done with event processing for now.
            // Leave the function:
            break;
        }
    }

#ifdef QT_MAC_USE_COCOA
    // In case we _now_ process events using [NSApp run], we need to stop it to
    // ensure that:
    //    1. the QEventLoop that called us is still executing, or
    //    2. we have a modal session that needs to be spun instead.
    // In case this is a plain call to processEvents (perhaps from a loop) 
    // from the application (rather than from a QEventLoop), we delay the
    // interrupting until we/ actually enter a lower loop level (hence the
    // deffered delete of the object below):
    QtMacInterruptDispatcherHelp::interruptLater();
#endif

    if (d->interrupt) {
        // We should continue to leave all recursion to processEvents until
        // processEvents is called again (e.g. from a QEventLoop that 
        // was not yet told to quit:
        interrupt();
    }

    return retVal;
}

void QEventDispatcherMac::wakeUp()
{
    Q_D(QEventDispatcherMac);
    d->serialNumber.ref();
    CFRunLoopSourceSignal(d->postedEventsSource);
    CFRunLoopWakeUp(mainRunLoop());
}

void QEventDispatcherMac::flush()
{
    if(qApp) {
        QWidgetList tlws = QApplication::topLevelWidgets();
        for(int i = 0; i < tlws.size(); i++) {
            QWidget *tlw = tlws.at(i);
            if(tlw->isVisible())
                macWindowFlush(qt_mac_window_for(tlw));
        }
    }
}

/*****************************************************************************
  QEventDispatcherMac Implementation
 *****************************************************************************/
MacTimerHash QEventDispatcherMacPrivate::macTimerHash;
bool QEventDispatcherMacPrivate::blockSendPostedEvents = false;

#ifdef QT_MAC_USE_COCOA
QStack<QCocoaModalSessionInfo> QEventDispatcherMacPrivate::cocoaModalSessionStack;
bool QEventDispatcherMacPrivate::currentExecIsNSAppRun = false;
bool QEventDispatcherMacPrivate::nsAppRunCalledByQt = false;
NSModalSession QEventDispatcherMacPrivate::currentModalSessionCached = 0;

int QEventDispatcherMacPrivate::activeModalSessionCount()
{
    // Returns the number of modal sessions created
    // (and not just pushed onto the stack, pending to be created)
    int count = 0;
    for (int i=cocoaModalSessionStack.size()-1; i>=0; --i) {
        QCocoaModalSessionInfo &info = cocoaModalSessionStack[i];
        if (info.session)
            ++count;
    }
    return count;
}

void QEventDispatcherMacPrivate::temporarilyStopAllModalSessions()
{
    // Stop all created modal session, and as such, make then
    // pending again. The next call to currentModalSession will
    // recreate the session on top again:
    int stackSize = cocoaModalSessionStack.size();
    for (int i=stackSize-1; i>=0; --i) {
        QCocoaModalSessionInfo &info = cocoaModalSessionStack[i];
        if (info.session) {
            [NSApp endModalSession:info.session];
            info.session = 0;
        }
    }
    currentModalSessionCached = 0;
}

NSModalSession QEventDispatcherMacPrivate::currentModalSession()
{
    // If we have one or more modal windows, this function will create
    // a session for each of those, and return the one for the top.
    if (currentModalSessionCached)
        return currentModalSessionCached;

    if (cocoaModalSessionStack.isEmpty())
        return 0;

    // Since this code will end up calling our Qt event handler
    // (also from beginModalSessionForWindow), we need to block
    // that to avoid side effects of events beeing delivered:
    QBoolBlocker block(blockSendPostedEvents, true);

    if (![NSApp isRunning]) {
        // Sadly, we need to introduce this little event flush
        // to stop dialogs from blinking/poping in front if a 
        // modal session restart was needed:
        while (NSEvent *event = [NSApp nextEventMatchingMask:0
                untilDate:nil
                inMode:NSDefaultRunLoopMode
                dequeue: YES]) {
            qt_mac_send_event(0, event, 0);
        }
    }

    int sessionCount = cocoaModalSessionStack.size();
    for (int i=0; i<sessionCount; ++i) {
        QCocoaModalSessionInfo &info = cocoaModalSessionStack[i];
        if (!info.widget)
            continue;
        if (info.widget->testAttribute(Qt::WA_DontShowOnScreen))
            continue;
        if (!info.session) {
            QMacCocoaAutoReleasePool pool;
            NSWindow *window = qt_mac_window_for(info.widget);
            if (!window)
                continue;
            info.session = [NSApp beginModalSessionForWindow:window];
        }
        currentModalSessionCached = info.session;
    }

    return currentModalSessionCached;
}

static void setChildrenWorksWhenModal(QWidget *widget, bool worksWhenModal)
{
    // For NSPanels (but not NSWindows, sadly), we can set the flag
    // worksWhenModal, so that they are active even when they are not modal. 
    QList<QDialog *> dialogs = widget->findChildren<QDialog *>();
    for (int i=0; i<dialogs.size(); ++i){
        NSWindow *window = qt_mac_window_for(dialogs[i]);
        if (window && [window isKindOfClass:[NSPanel class]]) {
            [static_cast<NSPanel *>(window) setWorksWhenModal:worksWhenModal];
            if (worksWhenModal && dialogs[i]->isVisible()){
                [window orderFront:window];
            }
        }
    }
}

void QEventDispatcherMacPrivate::updateChildrenWorksWhenModal()
{
    // Make the dialog children of the widget
    // active. And make the dialog children of
    // the previous modal dialog unactive again:
    int size = cocoaModalSessionStack.size();
    if (size > 0){
        if (QWidget *prevModal = cocoaModalSessionStack[size-1].widget)
            setChildrenWorksWhenModal(prevModal, true);
        if (size > 1){
            if (QWidget *prevModal = cocoaModalSessionStack[size-2].widget)
                setChildrenWorksWhenModal(prevModal, false);
        }
    }
}

void QEventDispatcherMacPrivate::beginModalSession(QWidget *widget)
{
    // Add a new, empty (null), NSModalSession to the stack.
    // It will become active the next time QEventDispatcher::processEvents is called.
    // A QCocoaModalSessionInfo is considered pending to become active if the widget pointer 
    // is non-zero, and the session pointer is zero (it will become active upon a call to
    // currentModalSession). A QCocoaModalSessionInfo is considered pending to be stopped if
    // the widget pointer is zero, and the session pointer is non-zero (it will be fully
    // stopped in endModalSession().
    QCocoaModalSessionInfo info = {widget, 0};
    cocoaModalSessionStack.push(info);
    updateChildrenWorksWhenModal();
    currentModalSessionCached = 0;
}

void QEventDispatcherMacPrivate::endModalSession(QWidget *widget)
{
    // Mark all sessions attached to widget as pending to be stopped. We do this
    // by setting the widget pointer to zero, but leave the session pointer.
    // We don't tell cocoa to stop any sessions just yet, because cocoa only understands
    // when we stop the _current_ modal session (which is the session on top of
    // the stack, and might not belong to 'widget'). 
    int stackSize = cocoaModalSessionStack.size();
    for (int i=stackSize-1; i>=0; --i) {
        QCocoaModalSessionInfo &info = cocoaModalSessionStack[i];
        if (info.widget == widget)
            info.widget = 0;
    }

    // Now we stop, and remove, all sessions marked as pending
    // to be stopped on _top_ of the stack, if any:
    bool needToInterruptEventDispatcher = false;
    bool needToUpdateChildrenWorksWhenModal = false;

    for (int i=stackSize-1; i>=0; --i) {
        QCocoaModalSessionInfo &info = cocoaModalSessionStack[i];
        if (info.widget)
            break;
        cocoaModalSessionStack.remove(i);
        needToUpdateChildrenWorksWhenModal = true;
        currentModalSessionCached = 0;
        if (info.session) {
            [NSApp endModalSession:info.session];
            needToInterruptEventDispatcher = true;
        }
    }

    if (needToUpdateChildrenWorksWhenModal)
        updateChildrenWorksWhenModal();
    if (needToInterruptEventDispatcher)
        QEventDispatcherMac::instance()->interrupt();
}

#endif

QEventDispatcherMacPrivate::QEventDispatcherMacPrivate()
    : interrupt(false)
{
}

QEventDispatcherMac::QEventDispatcherMac(QObject *parent)
    : QAbstractEventDispatcher(*new QEventDispatcherMacPrivate, parent)
{
    Q_D(QEventDispatcherMac);
    CFRunLoopSourceContext context;
    bzero(&context, sizeof(CFRunLoopSourceContext));
    context.info = d;
    context.equal = QEventDispatcherMacPrivate::postedEventSourceEqualCallback;
    context.perform = QEventDispatcherMacPrivate::postedEventsSourcePerformCallback;
    d->postedEventsSource = CFRunLoopSourceCreate(0, 0, &context);
    Q_ASSERT(d->postedEventsSource);
    CFRunLoopAddSource(mainRunLoop(), d->postedEventsSource, kCFRunLoopCommonModes);

    CFRunLoopObserverContext observerContext;
    bzero(&observerContext, sizeof(CFRunLoopObserverContext));
    observerContext.info = this;
    d->waitingObserver = CFRunLoopObserverCreate(kCFAllocatorDefault,
                                                 kCFRunLoopBeforeWaiting | kCFRunLoopAfterWaiting,
                                                 true, 0,
                                                 QEventDispatcherMacPrivate::waitingObserverCallback,
                                                 &observerContext);
    CFRunLoopAddObserver(mainRunLoop(), d->waitingObserver, kCFRunLoopCommonModes);

    /* The first cycle in the loop adds the source and the events of the source
       are not processed.
       We use an observer to process the posted events for the first
       execution of the loop. */
    CFRunLoopObserverContext firstTimeObserverContext;
    bzero(&firstTimeObserverContext, sizeof(CFRunLoopObserverContext));
    firstTimeObserverContext.info = d;
    d->firstTimeObserver = CFRunLoopObserverCreate(kCFAllocatorDefault,
                                                   kCFRunLoopEntry,
                                                   /* repeats = */ false,
                                                   0,
                                                   QEventDispatcherMacPrivate::firstLoopEntry,
                                                   &firstTimeObserverContext);
    CFRunLoopAddObserver(mainRunLoop(), d->firstTimeObserver, kCFRunLoopCommonModes);
}

void QEventDispatcherMacPrivate::waitingObserverCallback(CFRunLoopObserverRef,
                                                          CFRunLoopActivity activity, void *info)
{
    if (activity == kCFRunLoopBeforeWaiting)
        emit static_cast<QEventDispatcherMac*>(info)->aboutToBlock();
    else
        emit static_cast<QEventDispatcherMac*>(info)->awake();
}

Boolean QEventDispatcherMacPrivate::postedEventSourceEqualCallback(const void *info1, const void *info2)
{
    return info1 == info2;
}

inline static void processPostedEvents(QEventDispatcherMacPrivate *const d, const bool blockSendPostedEvents)
{
    if (blockSendPostedEvents || d->interrupt) {
        CFRunLoopSourceSignal(d->postedEventsSource);
    } else {
        if (!d->threadData->canWait || (d->serialNumber != d->lastSerial)) {
            d->lastSerial = d->serialNumber;
            QApplicationPrivate::sendPostedEvents(0, 0, d->threadData);
        }
    }
}

void QEventDispatcherMacPrivate::firstLoopEntry(CFRunLoopObserverRef ref,
                                                CFRunLoopActivity activity,
                                                void *info)
{
    Q_UNUSED(ref);
    Q_UNUSED(activity);
    processPostedEvents(static_cast<QEventDispatcherMacPrivate *>(info), blockSendPostedEvents);
}

void QEventDispatcherMacPrivate::postedEventsSourcePerformCallback(void *info)
{
    processPostedEvents(static_cast<QEventDispatcherMacPrivate *>(info), blockSendPostedEvents);
}

void QEventDispatcherMac::interrupt()
{
    Q_D(QEventDispatcherMac);
    d->interrupt = true;
    wakeUp();

#ifndef QT_MAC_USE_COCOA
    CFRunLoopStop(mainRunLoop());
#else
    QMacCocoaAutoReleasePool pool;
    // In case we wait for more events inside
    // processEvents (or NSApp run), post a dummy to wake it up:
    static const short NSAppShouldStopForQt = SHRT_MAX;
    [NSApp postEvent:[NSEvent otherEventWithType:NSApplicationDefined location:NSZeroPoint
        modifierFlags:0 timestamp:0. windowNumber:0 context:0
        subtype:NSAppShouldStopForQt data1:0 data2:0] atStart:NO];

    if (d->activeModalSessionCount() == 0) {
        // We should only stop NSApp if we actually started it (and
        // not some 3rd party application, e.g. if we are a plugin).
        if (d->nsAppRunCalledByQt)
            [NSApp stop:NSApp];
    }
#endif
}

QEventDispatcherMac::~QEventDispatcherMac()
{
    Q_D(QEventDispatcherMac);
    //timer cleanup
    MacTimerHash::iterator it = QEventDispatcherMacPrivate::macTimerHash.begin();
    while (it != QEventDispatcherMacPrivate::macTimerHash.end()) {
        MacTimerInfo *t = it.value();
        if (t->runLoopTimer) {
            CFRunLoopTimerInvalidate(t->runLoopTimer);
            CFRelease(t->runLoopTimer);
        }
        delete t;
        ++it;
    }
    QEventDispatcherMacPrivate::macTimerHash.clear();

    // Remove CFSockets from the runloop.
    for (MacSocketHash::ConstIterator it = d->macSockets.constBegin(); it != d->macSockets.constEnd(); ++it) {
        MacSocketInfo *socketInfo = (*it);
        if (CFSocketIsValid(socketInfo->socket)) {
            qt_mac_remove_socket_from_runloop(socketInfo->socket, socketInfo->runloop);
            CFRunLoopSourceInvalidate(socketInfo->runloop);
            CFRelease(socketInfo->runloop);
            CFSocketInvalidate(socketInfo->socket);
            CFRelease(socketInfo->socket);
        }
    }
    CFRunLoopRemoveSource(mainRunLoop(), d->postedEventsSource, kCFRunLoopCommonModes);
    CFRelease(d->postedEventsSource);

    CFRunLoopObserverInvalidate(d->waitingObserver);
    CFRelease(d->waitingObserver);

    CFRunLoopObserverInvalidate(d->firstTimeObserver);
    CFRelease(d->firstTimeObserver);
}

/////////////////////////////////////////////////////////////////////////////

#ifdef QT_MAC_USE_COCOA

QtMacInterruptDispatcherHelp* QtMacInterruptDispatcherHelp::instance = 0;

QtMacInterruptDispatcherHelp::QtMacInterruptDispatcherHelp() : cancelled(false)
{
    // This is the whole point of encapsulation this code
    // inside a class; we can make the code (inside destructor)
    // execute on lower loop level:
    deleteLater();
}

QtMacInterruptDispatcherHelp::~QtMacInterruptDispatcherHelp()
{
    if (cancelled)
        return;

    instance = 0;

    if (QEventDispatcherMacPrivate::currentExecIsNSAppRun) {
        int activeCount = QEventDispatcherMacPrivate::activeModalSessionCount();
        if (activeCount > 0) {
            // The problem we now have hit: [NSApp stop] will not stop NSApp
            // if a session is active; it will stop the session instead.
            // So to stop NSApp, we need to temporarily stop all the
            // sessions, then stop NSApp, then restart the session on top again.
            // We need to do this to ensure that we're not stuck inside
            // [NSApp run] when we really should be running a modal session:
            QEventDispatcherMacPrivate::temporarilyStopAllModalSessions();
        }
    }
    // Always interrupt once more in case the modal session stack changed
    // while processEvents was called manually from within the application:
    QEventDispatcherMac::instance()->interrupt();
}

void QtMacInterruptDispatcherHelp::interruptLater() {
    if (instance) {
        instance->cancelled = true;
        delete instance;
    }
    instance = new QtMacInterruptDispatcherHelp;
}

#endif

QT_END_NAMESPACE
