// -*- mode: c++; c-basic-offset: 4 -*-

/*

 * This file is part of the KDE libraries

 * Copyright (C) 2005 Apple Computer, Inc.

 *

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Library General Public

 * License as published by the Free Software Foundation; either

 * version 2 of the License, or (at your option) any later version.

 *

 * This library is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Library General Public License for more details.

 *

 * You should have received a copy of the GNU Library General Public License

 * along with this library; see the file COPYING.LIB.  If not, write to

 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,

 * Boston, MA 02110-1301, USA 

 *

 */

#include "config.h"

#include "JSLock.h"

#include "collector.h"

#if USE(MULTIPLE_THREADS)

#include <pthread.h>

#endif

namespace KJS {

#if USE(MULTIPLE_THREADS)

// Acquire this mutex before accessing lock-related data.

static pthread_mutex_t JSMutex = PTHREAD_MUTEX_INITIALIZER;

// Thread-specific key that tells whether a thread holds the JSMutex.

pthread_key_t didLockJSMutex;

// Lock nesting count.

static int JSLockCount;

static void createDidLockJSMutex()

{

    pthread_key_create(&didLockJSMutex, 0);

}

pthread_once_t createDidLockJSMutexOnce = PTHREAD_ONCE_INIT;

void JSLock::lock()

{

    pthread_once(&createDidLockJSMutexOnce, createDidLockJSMutex);

    if (!pthread_getspecific(didLockJSMutex)) {

        int result;

        result = pthread_mutex_lock(&JSMutex);

        ASSERT(!result);

        pthread_setspecific(didLockJSMutex, &didLockJSMutex);

    }

    ++JSLockCount;

}

void JSLock::unlock()

{

    ASSERT(JSLockCount);

    ASSERT(!!pthread_getspecific(didLockJSMutex));

    --JSLockCount;

    if (!JSLockCount) {

        pthread_setspecific(didLockJSMutex, 0);

        int result;

        result = pthread_mutex_unlock(&JSMutex);

        ASSERT(!result);

    }

}

bool JSLock::currentThreadIsHoldingLock()

{

    pthread_once(&createDidLockJSMutexOnce, createDidLockJSMutex);

    return !!pthread_getspecific(didLockJSMutex);

}

void JSLock::registerThread()

{

    Collector::registerThread();

}

JSLock::DropAllLocks::DropAllLocks()

    : m_lockCount(0)

{

    pthread_once(&createDidLockJSMutexOnce, createDidLockJSMutex);

    m_lockCount = !!pthread_getspecific(didLockJSMutex) ? JSLock::lockCount() : 0;

    for (int i = 0; i < m_lockCount; i++)

        JSLock::unlock();

}

JSLock::DropAllLocks::~DropAllLocks()

{

    for (int i = 0; i < m_lockCount; i++)

        JSLock::lock();

    m_lockCount = 0;

}

#else

// If threading support is off, set the lock count to a constant value of 1 so assertions

// that the lock is held don't fail

const int JSLockCount = 1;

bool JSLock::currentThreadIsHoldingLock()

{

    return true;

}

EXPORT 

void JSLock::lock()

{

}

EXPORT 

void JSLock::unlock()

{

}

EXPORT

void JSLock::registerThread()

{

}

EXPORT

JSLock::DropAllLocks::DropAllLocks()

{

}

EXPORT

JSLock::DropAllLocks::~DropAllLocks()

{

}

#endif // USE(MULTIPLE_THREADS)

int JSLock::lockCount()

{

    return JSLockCount;

}

}