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#include "qplatformdefs.h"

#include "qwaitcondition.h"

#include "qmutex.h"

#include "qreadwritelock.h"

#include "qatomic.h"

#include "qstring.h"

#include "qmutex_p.h"

#include "qreadwritelock_p.h"

#include <errno.h>

#ifndef QT_NO_THREAD

QT_BEGIN_NAMESPACE

static void report_error(int code, const char *where, const char *what)

{

    if (code != 0)

        qWarning("%s: %s failure: %s", where, what, qPrintable(qt_error_string(code)));

}

struct QWaitConditionPrivate {

    pthread_mutex_t mutex;

    pthread_cond_t cond;

    int waiters;

    int wakeups;

    bool wait(unsigned long time)

    {

        int code;

        forever {

            if (time != ULONG_MAX) {

                struct timeval tv;

                gettimeofday(&tv, 0);

                timespec ti;

                ti.tv_nsec = (tv.tv_usec + (time % 1000) * 1000) * 1000;

                ti.tv_sec = tv.tv_sec + (time / 1000) + (ti.tv_nsec / 1000000000);

                ti.tv_nsec %= 1000000000;

                code = pthread_cond_timedwait(&cond, &mutex, &ti);

            } else {

                code = pthread_cond_wait(&cond, &mutex);

            }

            if (code == 0 && wakeups == 0) {

                // many vendors warn of spurios wakeups from

                // pthread_cond_wait(), especially after signal delivery,

                // even though POSIX doesn't allow for it... sigh

                continue;

            }

            break;

        }

        Q_ASSERT_X(waiters > 0, "QWaitCondition::wait", "internal error (waiters)");

        --waiters;

        if (code == 0) {

            Q_ASSERT_X(wakeups > 0, "QWaitCondition::wait", "internal error (wakeups)");

            --wakeups;

        }

        report_error(pthread_mutex_unlock(&mutex), "QWaitCondition::wait()", "mutex unlock");

        if (code && code != ETIMEDOUT)

            report_error(code, "QWaitCondition::wait()", "cv wait");

        return (code == 0);

    }

};

QWaitCondition::QWaitCondition()

{

    d = new QWaitConditionPrivate;

    report_error(pthread_mutex_init(&d->mutex, NULL), "QWaitCondition", "mutex init");

    report_error(pthread_cond_init(&d->cond, NULL), "QWaitCondition", "cv init");

    d->waiters = d->wakeups = 0;

}

QWaitCondition::~QWaitCondition()

{

    report_error(pthread_cond_destroy(&d->cond), "QWaitCondition", "cv destroy");

    report_error(pthread_mutex_destroy(&d->mutex), "QWaitCondition", "mutex destroy");

    delete d;

}

void QWaitCondition::wakeOne()

{

    report_error(pthread_mutex_lock(&d->mutex), "QWaitCondition::wakeOne()", "mutex lock");

    d->wakeups = qMin(d->wakeups + 1, d->waiters);

    report_error(pthread_cond_signal(&d->cond), "QWaitCondition::wakeOne()", "cv signal");

    report_error(pthread_mutex_unlock(&d->mutex), "QWaitCondition::wakeOne()", "mutex unlock");

}

void QWaitCondition::wakeAll()

{

    report_error(pthread_mutex_lock(&d->mutex), "QWaitCondition::wakeAll()", "mutex lock");

    d->wakeups = d->waiters;

    report_error(pthread_cond_broadcast(&d->cond), "QWaitCondition::wakeAll()", "cv broadcast");

    report_error(pthread_mutex_unlock(&d->mutex), "QWaitCondition::wakeAll()", "mutex unlock");

}

bool QWaitCondition::wait(QMutex *mutex, unsigned long time)

{

    if (! mutex)

        return false;

    if (mutex->d->recursive) {

        qWarning("QWaitCondition: cannot wait on recursive mutexes");

        return false;

    }

    report_error(pthread_mutex_lock(&d->mutex), "QWaitCondition::wait()", "mutex lock");

    ++d->waiters;

    mutex->unlock();

    bool returnValue = d->wait(time);

    mutex->lock();

    return returnValue;

}

bool QWaitCondition::wait(QReadWriteLock *readWriteLock, unsigned long time)

{

    if (!readWriteLock || readWriteLock->d->accessCount == 0)

        return false;

    if (readWriteLock->d->accessCount < -1) {

        qWarning("QWaitCondition: cannot wait on QReadWriteLocks with recursive lockForWrite()");

        return false;

    }

    report_error(pthread_mutex_lock(&d->mutex), "QWaitCondition::wait()", "mutex lock");

    ++d->waiters;

    int previousAccessCount = readWriteLock->d->accessCount;

    readWriteLock->unlock();

    bool returnValue = d->wait(time);

    if (previousAccessCount < 0)

        readWriteLock->lockForWrite();

    else

        readWriteLock->lockForRead();

    return returnValue;

}

QT_END_NAMESPACE

#endif // QT_NO_THREAD