/*

 * Copyright (C) 2005, 2006, 2007 Apple Inc. All rights reserved.

 *           (C) 2007 Graham Dennis (graham.dennis@gmail.com)

 *           (C) 2007 Eric Seidel <eric@webkit.org>

 *

 * 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 "JavaScriptThreading.h"

#include <CoreFoundation/CoreFoundation.h>

#include <JavaScriptCore/JavaScriptCore.h>

#include <pthread.h>

#include <wtf/Assertions.h>

#include <wtf/HashSet.h>

static pthread_mutex_t javaScriptThreadsMutex = PTHREAD_MUTEX_INITIALIZER;

static bool javaScriptThreadsShouldTerminate;

static const int javaScriptThreadsCount = 4;

typedef HashSet<pthread_t> ThreadSet;

static ThreadSet* javaScriptThreads()

{

    ASSERT(pthread_mutex_trylock(&javaScriptThreadsMutex) == EBUSY);

    static ThreadSet staticJavaScriptThreads;

    return &staticJavaScriptThreads;

}

// Loops forever, running a script and randomly respawning, until 

// javaScriptThreadsShouldTerminate becomes true.

void* runJavaScriptThread(void* arg)

{

    const char* const script =

        "var array = [];"

        "for (var i = 0; i < 10; i++) {"

        "    array.push(String(i));"

        "}";

    while (1) {

        JSGlobalContextRef ctx = JSGlobalContextCreate(0);

        JSStringRef scriptRef = JSStringCreateWithUTF8CString(script);

        JSValueRef exception = 0;

        JSEvaluateScript(ctx, scriptRef, 0, 0, 1, &exception);

        ASSERT(!exception);

        JSGarbageCollect(ctx);

        JSGlobalContextRelease(ctx);

        JSStringRelease(scriptRef);

        JSGarbageCollect(0);

        pthread_mutex_lock(&javaScriptThreadsMutex);

        // Check for cancellation.

        if (javaScriptThreadsShouldTerminate) {

            javaScriptThreads()->remove(pthread_self());

            pthread_mutex_unlock(&javaScriptThreadsMutex);

            return 0;

        }

        // Respawn probabilistically.

        if (random() % 5 == 0) {

            pthread_t pthread;

            pthread_create(&pthread, 0, &runJavaScriptThread, 0);

            pthread_detach(pthread);

            javaScriptThreads()->remove(pthread_self());

            javaScriptThreads()->add(pthread);

            pthread_mutex_unlock(&javaScriptThreadsMutex);

            return 0;

        }

        pthread_mutex_unlock(&javaScriptThreadsMutex);

    }

}

void startJavaScriptThreads()

{

    pthread_mutex_lock(&javaScriptThreadsMutex);

    for (int i = 0; i < javaScriptThreadsCount; i++) {

        pthread_t pthread;

        pthread_create(&pthread, 0, &runJavaScriptThread, 0);

        pthread_detach(pthread);

        javaScriptThreads()->add(pthread);

    }

    pthread_mutex_unlock(&javaScriptThreadsMutex);

}

void stopJavaScriptThreads()

{

    pthread_mutex_lock(&javaScriptThreadsMutex);

    javaScriptThreadsShouldTerminate = true;

    ASSERT(javaScriptThreads()->size() == javaScriptThreadsCount);

    pthread_mutex_unlock(&javaScriptThreadsMutex);

    while (true) {

        pthread_mutex_lock(&javaScriptThreadsMutex);

        int threadCount = javaScriptThreads()->size();

        pthread_mutex_unlock(&javaScriptThreadsMutex);

        if (!threadCount)

            break;

        usleep(1000);

    }

}