qeventdispatcher_unix.cpp

QT 开发环境里面一个很重要的文件

    }

    Q_D(QEventDispatcherUNIX);
    if (d->timerList.isEmpty())
        return false;
    for (int i = 0; i < d->timerList.size(); ++i) {
        register QTimerInfo *t = d->timerList.at(i);
        if (t->obj == object) {
            // object found
            d->timerList.removeAt(i);
            delete t;
            // move back one so that we don't skip the new current item
            --i;
        }
    }
    return true;
}

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

    Q_D(const QEventDispatcherUNIX);
    QList<TimerInfo> list;
    for (int i = 0; i < d->timerList.size(); ++i) {
        register const QTimerInfo * const t = d->timerList.at(i);
        if (t->obj == object)
            list << TimerInfo(t->id, t->interval.tv_sec * 1000 + t->interval.tv_usec / 1000);
    }
    return list;
}

/*****************************************************************************
 Socket notifier type
 *****************************************************************************/
QSockNotType::QSockNotType()
{
    FD_ZERO(&select_fds);
    FD_ZERO(&enabled_fds);
    FD_ZERO(&pending_fds);
}

QSockNotType::~QSockNotType()
{
    while (!list.isEmpty())
        delete list.takeFirst();
}

/*****************************************************************************
 QEventDispatcher implementations for UNIX
 *****************************************************************************/

void QEventDispatcherUNIX::registerSocketNotifier(QSocketNotifier *notifier)
{
    int sockfd;
    int type;
    if (!notifier
        || (sockfd = notifier->socket()) < 0
        || unsigned(sockfd) >= FD_SETSIZE
        || (type = notifier->type()) < 0
        || type > 2) {
        qWarning("QSocketNotifier: Internal error");
        return;
    } else if (notifier->thread() != thread()
               || thread() != QThread::currentThread()) {
        qWarning("QSocketNotifier: socket notifiers cannot be enabled from another thread");
        return;
    }

    Q_D(QEventDispatcherUNIX);
    QList<QSockNot *> &list = d->sn_vec[type].list;
    fd_set *fds  = &d->sn_vec[type].enabled_fds;
    QSockNot *sn;

    sn = new QSockNot;
    sn->obj = notifier;
    sn->fd = sockfd;
    sn->queue = &d->sn_vec[type].pending_fds;

    int i;
    for (i = 0; i < list.size(); ++i) {
        QSockNot *p = list.at(i);
        if (p->fd < sockfd)
            break;
        if (p->fd == sockfd) {
            static const char *t[] = { "Read", "Write", "Exception" };
            qWarning("QSocketNotifier: Multiple socket notifiers for "
                      "same socket %d and type %s", sockfd, t[type]);
        }
    }
    list.insert(i, sn);

    FD_SET(sockfd, fds);
    d->sn_highest = qMax(d->sn_highest, sockfd);
}

void QEventDispatcherUNIX::unregisterSocketNotifier(QSocketNotifier *notifier)
{
    int sockfd;
    int type;
    if (!notifier
        || (sockfd = notifier->socket()) < 0
        || unsigned(sockfd) >= FD_SETSIZE
        || (type = notifier->type()) < 0
        || type > 2) {
        qWarning("QSocketNotifier: Internal error");
        return;
    } else if (notifier->thread() != thread()
               || thread() != QThread::currentThread()) {
        qWarning("QSocketNotifier: socket notifiers cannot be disabled from another thread");
        return;
    }

    Q_D(QEventDispatcherUNIX);
    QList<QSockNot *> &list = d->sn_vec[type].list;
    fd_set *fds  =  &d->sn_vec[type].enabled_fds;
    QSockNot *sn;
    int i;
    for (i = 0; i < list.size(); ++i) {
        sn = list.at(i);
        if(sn->obj == notifier && sn->fd == sockfd)
            break;
    }
    if (i == list.size()) // not found
        return;

    FD_CLR(sockfd, fds);                        // clear fd bit
    FD_CLR(sockfd, sn->queue);
    d->sn_pending_list.removeAll(sn);                // remove from activation list
    list.removeAt(i);                                // remove notifier found above
    delete sn;

    if (d->sn_highest == sockfd) {                // find highest fd
        d->sn_highest = -1;
        for (int i=0; i<3; i++) {
            if (!d->sn_vec[i].list.isEmpty())
                d->sn_highest = qMax(d->sn_highest,  // list is fd-sorted
                                     d->sn_vec[i].list.first()->fd);
        }
    }
}

void QEventDispatcherUNIX::setSocketNotifierPending(QSocketNotifier *notifier)
{
    int sockfd;
    int type;
    if (!notifier
        || (sockfd = notifier->socket()) < 0
        || sockfd > FD_SETSIZE
        || (type = notifier->type()) < 0
        || type > 2) {
        qWarning("QSocketNotifier: Internal error");
        return;
    }

    Q_ASSERT(notifier->thread() == thread() && thread() == QThread::currentThread());

    Q_D(QEventDispatcherUNIX);
    QList<QSockNot *> &list = d->sn_vec[type].list;
    QSockNot *sn = 0;
    int i;
    for (i = 0; i < list.size(); ++i) {
        sn = list.at(i);
        if(sn->obj == notifier && sn->fd == sockfd)
            break;
    }
    if (i == list.size()) // not found
        return;

    // We choose a random activation order to be more fair under high load.
    // If a constant order is used and a peer early in the list can
    // saturate the IO, it might grab our attention completely.
    // Also, if we're using a straight list, the callback routines may
    // delete other entries from the list before those other entries are
    // processed.
    if (! FD_ISSET(sn->fd, sn->queue)) {
        d->sn_pending_list.insert((qrand() & 0xff) %
                                  (d->sn_pending_list.size()+1), sn);
        FD_SET(sn->fd, sn->queue);
    }
}

int QEventDispatcherUNIX::activateTimers()
{
    Q_ASSERT(thread() == QThread::currentThread());

    Q_D(QEventDispatcherUNIX);
    if (qt_disable_lowpriority_timers || d->timerList.isEmpty())
        return 0; // nothing to do

    bool first = true;
    timeval currentTime;
    int n_act = 0, maxCount = d->timerList.size();
    QTimerInfo *begin = 0;

    while (maxCount--) {
        getTime(currentTime);
        if (first) {
            d->timerList.updateWatchTime(currentTime);
            first = false;
        }

        if (d->timerList.isEmpty()) break;
        QTimerInfo *t = d->timerList.first();
        if (currentTime < t->timeout)
            break; // no timer has expired

        if (!begin) {
            begin = t;
        } else if (begin == t) {
            // avoid sending the same timer multiple times
            break;
        } else if (t->interval <  begin->interval || t->interval == begin->interval) {
            begin = t;
        }

        // remove from list
        d->timerList.removeFirst();
        t->timeout += t->interval;
        if (t->timeout < currentTime)
            t->timeout = currentTime + t->interval;

        // reinsert timer
        d->timerList.timerInsert(t);
        if (t->interval.tv_usec > 0 || t->interval.tv_sec > 0)
            n_act++;

        if (!t->inTimerEvent) {
            // send event, but don't allow it to recurse
            t->inTimerEvent = true;

            QTimerEvent e(t->id);
            QCoreApplication::sendEvent(t->obj, &e);

            if (d->timerList.contains(t))
                t->inTimerEvent = false;
        }

        if (!d->timerList.contains(begin)) begin = 0;
    }
    return n_act;
}

int QEventDispatcherUNIX::activateSocketNotifiers()
{
    Q_D(QEventDispatcherUNIX);
    if (d->sn_pending_list.isEmpty())
        return 0;

    // create sets that match the current pending sets (note: we skip
    // the first one, because we activate first and check second)
    fd_set rset, wset, xset;
    FD_ZERO(&rset);
    FD_ZERO(&wset);
    FD_ZERO(&xset);
    for (int i = 1; i < d->sn_pending_list.size(); ++i) {
        const QSockNot * const sn = d->sn_pending_list.at(i);
        switch (sn->obj->type()) {
        case QSocketNotifier::Read:
            FD_SET(sn->fd, &rset);
            break;
        case QSocketNotifier::Write:
            FD_SET(sn->fd, &wset);
            break;
        case QSocketNotifier::Exception:
            FD_SET(sn->fd, &xset);
            break;
        }
    }

    // activate entries
    int n_act = 0;
    QEvent event(QEvent::SockAct);
    while (!d->sn_pending_list.isEmpty()) {
        QSockNot *sn = d->sn_pending_list.takeFirst();
        if (FD_ISSET(sn->fd, sn->queue)) {
            FD_CLR(sn->fd, sn->queue);
            QCoreApplication::sendEvent(sn->obj, &event);
            ++n_act;
        }
    }
    return n_act;
}

bool QEventDispatcherUNIX::processEvents(QEventLoop::ProcessEventsFlags flags)
{
    Q_D(QEventDispatcherUNIX);
    d->interrupt = false;

    // we are awake, broadcast it
    emit awake();
    QCoreApplication::sendPostedEvents(0, (flags & QEventLoop::DeferredDeletion) ? -1 : 0);

    int nevents = 0;
    const bool canWait = (d->threadData->canWait
                          && !d->interrupt
                          && (flags & QEventLoop::WaitForMoreEvents));

    if (canWait)
        emit aboutToBlock();

    if (!d->interrupt) {
        // return the maximum time we can wait for an event.
        timeval *tm = 0;
        timeval wait_tm = { 0l, 0l };
        if (!(flags & QEventLoop::X11ExcludeTimers)) {
            if (d->timerList.timerWait(wait_tm))
                tm = &wait_tm;

            if (!canWait) {
                if (!tm)
                    tm = &wait_tm;

                // no time to wait
                tm->tv_sec  = 0l;
                tm->tv_usec = 0l;
            }
        }

        nevents = d->doSelect(flags, tm);

        // activate timers
        if (! (flags & QEventLoop::X11ExcludeTimers)) {
            nevents += activateTimers();
        }
    }
    // return true if we handled events, false otherwise
    return (nevents > 0);
}

bool QEventDispatcherUNIX::hasPendingEvents()
{
    extern uint qGlobalPostedEventsCount(); // from qapplication.cpp
    return qGlobalPostedEventsCount();
}

void QEventDispatcherUNIX::wakeUp()
{
    Q_D(QEventDispatcherUNIX);
    if (d->wakeUps.testAndSetAcquire(0, 1)) {
        char c = 0;
        ::write( d->thread_pipe[1], &c, 1 );
    }
}

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

void QEventDispatcherUNIX::flush()
{ }




void QCoreApplication::watchUnixSignal(int sig, bool watch)
{
    if (sig < NSIG) {
        struct sigaction sa;
        sigemptyset(&(sa.sa_mask));
        sa.sa_flags = 0;
        if (watch)
            sa.sa_handler = signalHandler;
        else
            sa.sa_handler = SIG_DFL;
        sigaction(sig, &sa, 0);
    }
}