qtbase/src/corelib/kernel/qtimerinfo_unix.cpp

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#include <qelapsedtimer.h>
#include <qcoreapplication.h>

#include "private/qcore_unix_p.h"
#include "private/qtimerinfo_unix_p.h"
#include "private/qobject_p.h"
#include "private/qabstracteventdispatcher_p.h"

#include <sys/times.h>

QT_BEGIN_NAMESPACE

Q_CORE_EXPORT bool qt_disable_lowpriority_timers=false;

/*
 * Internal functions for manipulating timer data structures.  The
 * timerBitVec array is used for keeping track of timer identifiers.
 */

QTimerInfoList::QTimerInfoList()
{
#if (_POSIX_MONOTONIC_CLOCK-0 <= 0) && !defined(Q_OS_MAC) && !defined(Q_OS_NACL)
    if (!QElapsedTimer::isMonotonic()) {
        // not using monotonic timers, initialize the timeChanged() machinery
        previousTime = qt_gettime();

        tms unused;
        previousTicks = times(&unused);

        ticksPerSecond = sysconf(_SC_CLK_TCK);
        msPerTick = 1000/ticksPerSecond;
    } else {
        // detected monotonic timers
        previousTime.tv_sec = previousTime.tv_usec = 0;
        previousTicks = 0;
        ticksPerSecond = 0;
        msPerTick = 0;
    }
#endif

    firstTimerInfo = 0;
}

timeval QTimerInfoList::updateCurrentTime()
{
    return (currentTime = qt_gettime());
}

#if ((_POSIX_MONOTONIC_CLOCK-0 <= 0) && !defined(Q_OS_MAC) && !defined(Q_OS_INTEGRITY)) || defined(QT_BOOTSTRAPPED)

template <>
timeval qAbs(const timeval &t)
{
    timeval tmp = t;
    if (tmp.tv_sec < 0) {
        tmp.tv_sec = -tmp.tv_sec - 1;
        tmp.tv_usec -= 1000000;
    }
    if (tmp.tv_sec == 0 && tmp.tv_usec < 0) {
        tmp.tv_usec = -tmp.tv_usec;
    }
    return normalizedTimeval(tmp);
}

/*
  Returns true if the real time clock has changed by more than 10%
  relative to the processor time since the last time this function was
  called. This presumably means that the system time has been changed.

  If /a delta is nonzero, delta is set to our best guess at how much the system clock was changed.
*/
bool QTimerInfoList::timeChanged(timeval *delta)
{
#ifdef Q_OS_NACL
    Q_UNUSED(delta)
    return false; // Calling "times" crashes.
#endif
    struct tms unused;
    clock_t currentTicks = times(&unused);

    clock_t elapsedTicks = currentTicks - previousTicks;
    timeval elapsedTime = currentTime - previousTime;

    timeval elapsedTimeTicks;
    elapsedTimeTicks.tv_sec = elapsedTicks / ticksPerSecond;
    elapsedTimeTicks.tv_usec = (((elapsedTicks * 1000) / ticksPerSecond) % 1000) * 1000;

    timeval dummy;
    if (!delta)
        delta = &dummy;
    *delta = elapsedTime - elapsedTimeTicks;

    previousTicks = currentTicks;
    previousTime = currentTime;

    // If tick drift is more than 10% off compared to realtime, we assume that the clock has
    // been set. Of course, we have to allow for the tick granularity as well.
    timeval tickGranularity;
    tickGranularity.tv_sec = 0;
    tickGranularity.tv_usec = msPerTick * 1000;
    return elapsedTimeTicks < ((qAbs(*delta) - tickGranularity) * 10);
}

void QTimerInfoList::repairTimersIfNeeded()
{
    if (QElapsedTimer::isMonotonic())
        return;
    timeval delta;
    if (timeChanged(&delta))
        timerRepair(delta);
}

#else // !(_POSIX_MONOTONIC_CLOCK-0 <= 0) && !defined(QT_BOOTSTRAPPED)

void QTimerInfoList::repairTimersIfNeeded()
{
}

#endif

/*
  insert timer info into list
*/
void QTimerInfoList::timerInsert(QTimerInfo *ti)
{
    int index = size();
    while (index--) {
        register const QTimerInfo * const t = at(index);
        if (!(ti->timeout < t->timeout))
            break;
    }
    insert(index+1, ti);
}

/*
  repair broken timer
*/
void QTimerInfoList::timerRepair(const timeval &diff)
{
    // repair all timers
    for (int i = 0; i < size(); ++i) {
        register QTimerInfo *t = at(i);
        t->timeout = t->timeout + diff;
    }
}

inline timeval &operator+=(timeval &t1, int ms)
{
    t1.tv_sec += ms / 1000;
    t1.tv_usec += ms % 1000 * 1000;
    return normalizedTimeval(t1);
}

inline timeval operator+(const timeval &t1, int ms)
{
    timeval t2 = t1;
    return t2 += ms;
}

static timeval roundToMillisecond(timeval val)
{
    // always round up
    // worst case scenario is that the first trigger of a 1-ms timer is 0.999 ms late

    int us = val.tv_usec % 1000;
    val.tv_usec += 1000 - us;
    return normalizedTimeval(val);
}

/*
  Returns the time to wait for the next timer, or null if no timers
  are waiting.
*/
bool QTimerInfoList::timerWait(timeval &tm)
{
    timeval currentTime = updateCurrentTime();
    repairTimersIfNeeded();

    // Find first waiting timer not already active
    QTimerInfo *t = 0;
    for (QTimerInfoList::const_iterator it = constBegin(); it != constEnd(); ++it) {
        if (!(*it)->activateRef) {
            t = *it;
            break;
        }
    }

    if (!t)
      return false;

    if (currentTime < t->timeout) {
        // time to wait
        tm = roundToMillisecond(t->timeout - currentTime);
    } else {
        // no time to wait
        tm.tv_sec  = 0;
        tm.tv_usec = 0;
    }

    return true;
}

void QTimerInfoList::registerTimer(int timerId, int interval, Qt::TimerType timerType, QObject *object)
{
    QTimerInfo *t = new QTimerInfo;
    t->id = timerId;
    t->interval = interval;
    t->timerType = timerType;
    t->timeout = updateCurrentTime() + t->interval;
    t->obj = object;
    t->activateRef = 0;

    timerInsert(t);
}

bool QTimerInfoList::unregisterTimer(int timerId)
{
    // set timer inactive
    for (int i = 0; i < count(); ++i) {
        register QTimerInfo *t = at(i);
        if (t->id == timerId) {
            // found it
            removeAt(i);
            if (t == firstTimerInfo)
                firstTimerInfo = 0;
            if (t->activateRef)
                *(t->activateRef) = 0;
            delete t;
            return true;
        }
    }
    // id not found
    return false;
}

bool QTimerInfoList::unregisterTimers(QObject *object)
{
    if (isEmpty())
        return false;
    for (int i = 0; i < count(); ++i) {
        register QTimerInfo *t = at(i);
        if (t->obj == object) {
            // object found
            removeAt(i);
            if (t == firstTimerInfo)
                firstTimerInfo = 0;
            if (t->activateRef)
                *(t->activateRef) = 0;
            delete t;
            // move back one so that we don't skip the new current item
            --i;
        }
    }
    return true;
}

QList<QAbstractEventDispatcher::TimerInfo> QTimerInfoList::registeredTimers(QObject *object) const
{
    QList<QAbstractEventDispatcher::TimerInfo> list;
    for (int i = 0; i < count(); ++i) {
        register const QTimerInfo * const t = at(i);
        if (t->obj == object)
            list << QAbstractEventDispatcher::TimerInfo(t->id, t->interval, t->timerType);
    }
    return list;
}

/*
    Activate pending timers, returning how many where activated.
*/
int QTimerInfoList::activateTimers()
{
    if (qt_disable_lowpriority_timers || isEmpty())
        return 0; // nothing to do

    int n_act = 0, maxCount = 0;
    firstTimerInfo = 0;

    timeval currentTime = updateCurrentTime();
    repairTimersIfNeeded();


    // Find out how many timer have expired
    for (QTimerInfoList::const_iterator it = constBegin(); it != constEnd(); ++it) {
        if (currentTime < (*it)->timeout)
            break;
        maxCount++;
    }

    //fire the timers.
    while (maxCount--) {
        if (isEmpty())
            break;

        QTimerInfo *currentTimerInfo = first();
        if (currentTime < currentTimerInfo->timeout)
            break; // no timer has expired

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

        // remove from list
        removeFirst();

        // determine next timeout time
        currentTimerInfo->timeout += currentTimerInfo->interval;
        if (currentTimerInfo->timeout < currentTime)
            currentTimerInfo->timeout = currentTime + currentTimerInfo->interval;

        // reinsert timer
        timerInsert(currentTimerInfo);
        if (currentTimerInfo->interval > 0)
            n_act++;

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

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

            if (currentTimerInfo)
                currentTimerInfo->activateRef = 0;
        }
    }

    firstTimerInfo = 0;
    return n_act;
}

QT_END_NAMESPACE