/*

 * Copyright (C) 2007 Apple Inc. All rights reserved.

 * Copyright (C) 2007 Justin Haygood (jhaygood@reaktix.com)

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 * 1.  Redistributions of source code must retain the above copyright

 *     notice, this list of conditions and the following disclaimer. 

 * 2.  Redistributions in binary form must reproduce the above copyright

 *     notice, this list of conditions and the following disclaimer in the

 *     documentation and/or other materials provided with the distribution. 

 * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of

 *     its contributors may be used to endorse or promote products derived

 *     from this software without specific prior written permission. 

 *

 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY

 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED

 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE

 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY

 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES

 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;

 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND

 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF

 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

#include "config.h"

#include "Threading.h"

#if !ENABLE(SINGLE_THREADED)

#include "CurrentTime.h"

#include "HashMap.h"

#include "MainThread.h"

#include "RandomNumberSeed.h"

#include <QCoreApplication>

#include <QMutex>

#include <QThread>

#include <QWaitCondition>

namespace WTF {

class ThreadPrivate : public QThread {

public:

    ThreadPrivate(ThreadFunction entryPoint, void* data);

    void run();

    void* getReturnValue() { return m_returnValue; }

private:

    void* m_data;

    ThreadFunction m_entryPoint;

    void* m_returnValue;

};

ThreadPrivate::ThreadPrivate(ThreadFunction entryPoint, void* data) 

    : m_data(data)

    , m_entryPoint(entryPoint)

    , m_returnValue(0)

{

}

void ThreadPrivate::run()

{

    m_returnValue = m_entryPoint(m_data);

}

class ThreadMonitor : public QObject {

    Q_OBJECT

public:

    static ThreadMonitor * instance()

    {

        static ThreadMonitor *instance = new ThreadMonitor();

        return instance;

    }

public Q_SLOTS:

    void threadFinished()

    {

        sender()->deleteLater();

    }

};

static Mutex* atomicallyInitializedStaticMutex;

static Mutex& threadMapMutex()

{

    static Mutex mutex;

    return mutex;

}

static HashMap<ThreadIdentifier, QThread*>& threadMap()

{

    static HashMap<ThreadIdentifier, QThread*> map;

    return map;

}

static ThreadIdentifier identifierByQthreadHandle(QThread*& thread)

{

    MutexLocker locker(threadMapMutex());

    HashMap<ThreadIdentifier, QThread*>::iterator i = threadMap().begin();

    for (; i != threadMap().end(); ++i) {

        if (i->second == thread)

            return i->first;

    }

    return 0;

}

static ThreadIdentifier establishIdentifierForThread(QThread*& thread)

{

    ASSERT(!identifierByQthreadHandle(thread));

    MutexLocker locker(threadMapMutex());

    static ThreadIdentifier identifierCount = 1;

    threadMap().add(identifierCount, thread);

    return identifierCount++;

}

static void clearThreadForIdentifier(ThreadIdentifier id)

{

    MutexLocker locker(threadMapMutex());

    ASSERT(threadMap().contains(id));

    threadMap().remove(id);

}

static QThread* threadForIdentifier(ThreadIdentifier id)

{

    MutexLocker locker(threadMapMutex());

    return threadMap().get(id);

}

void initializeThreading()

{

    if (!atomicallyInitializedStaticMutex) {

        atomicallyInitializedStaticMutex = new Mutex;

        threadMapMutex();

        initializeRandomNumberGenerator();

    }

}

void lockAtomicallyInitializedStaticMutex()

{

    ASSERT(atomicallyInitializedStaticMutex);

    atomicallyInitializedStaticMutex->lock();

}

void unlockAtomicallyInitializedStaticMutex()

{

    atomicallyInitializedStaticMutex->unlock();

}

ThreadIdentifier createThreadInternal(ThreadFunction entryPoint, void* data, const char*)

{

    ThreadPrivate* thread = new ThreadPrivate(entryPoint, data);

    if (!thread) {

        LOG_ERROR("Failed to create thread at entry point %p with data %p", entryPoint, data);

        return 0;

    }

    QObject::connect(thread, SIGNAL(finished()), ThreadMonitor::instance(), SLOT(threadFinished()));

    thread->start();

    QThread* threadRef = static_cast<QThread*>(thread);

    return establishIdentifierForThread(threadRef);

}

void initializeCurrentThreadInternal(const char*)

{

}

int waitForThreadCompletion(ThreadIdentifier threadID, void** result)

{

    ASSERT(threadID);

    QThread* thread = threadForIdentifier(threadID);

    bool res = thread->wait();

    clearThreadForIdentifier(threadID);

    if (result)

        *result = static_cast<ThreadPrivate*>(thread)->getReturnValue();

    return !res;

}

void detachThread(ThreadIdentifier threadID)

{

    ASSERT(threadID);

    clearThreadForIdentifier(threadID);

}

ThreadIdentifier currentThread()

{

    QThread* currentThread = QThread::currentThread();

    if (ThreadIdentifier id = identifierByQthreadHandle(currentThread))

        return id;

    return establishIdentifierForThread(currentThread);

}

Mutex::Mutex()

    : m_mutex(new QMutex())

{

}

Mutex::~Mutex()

{

    delete m_mutex;

}

void Mutex::lock()

{

    m_mutex->lock();

}

bool Mutex::tryLock()

{

    return m_mutex->tryLock();

}

void Mutex::unlock()

{

    m_mutex->unlock();

}

ThreadCondition::ThreadCondition()

    : m_condition(new QWaitCondition())

{

}

ThreadCondition::~ThreadCondition()

{

    delete m_condition;

}

void ThreadCondition::wait(Mutex& mutex)

{

    m_condition->wait(mutex.impl());

}

bool ThreadCondition::timedWait(Mutex& mutex, double absoluteTime)

{

    double currentTime = WTF::currentTime();

    // Time is in the past - return immediately.

    if (absoluteTime < currentTime)

        return false;

    // Time is too far in the future (and would overflow unsigned long) - wait forever.

    if (absoluteTime - currentTime > static_cast<double>(INT_MAX) / 1000.0) {

        wait(mutex);

        return true;

    }

    double intervalMilliseconds = (absoluteTime - currentTime) * 1000.0;

    return m_condition->wait(mutex.impl(), static_cast<unsigned long>(intervalMilliseconds));

}

void ThreadCondition::signal()

{

    m_condition->wakeOne();

}

void ThreadCondition::broadcast()

{

    m_condition->wakeAll();

}

} // namespace WebCore

#include "ThreadingQt.moc"

#endif