1 /*

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

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

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

     5  *

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

     7  * modification, are permitted provided that the following conditions

     8  * are met:

     9  *

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

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

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

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

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

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

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

    17  *     from this software without specific prior written permission. 

    18  *

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

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

    21  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE

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

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

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

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

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

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

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

    29  */

    30  

    31 #include "config.h"

    32 #include "JavaScriptThreading.h"

    33 

    34 #include <CoreFoundation/CoreFoundation.h>

    35 #include <JavaScriptCore/JavaScriptCore.h>

    36 #include <pthread.h>

    37 #include <wtf/Assertions.h>

    38 #include <wtf/HashSet.h>

    39 

    40 static pthread_mutex_t javaScriptThreadsMutex = PTHREAD_MUTEX_INITIALIZER;

    41 static bool javaScriptThreadsShouldTerminate;

    42 

    43 static const int javaScriptThreadsCount = 4;

    44 

    45 typedef HashSet<pthread_t> ThreadSet;

    46 

    47 static ThreadSet* javaScriptThreads()

    48 {

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

    50     static ThreadSet staticJavaScriptThreads;

    51     return &staticJavaScriptThreads;

    52 }

    53 

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

    55 // javaScriptThreadsShouldTerminate becomes true.

    56 void* runJavaScriptThread(void* arg)

    57 {

    58     const char* const script =

    59         "var array = [];"

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

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

    62         "}";

    63 

    64     while (1) {

    65         JSGlobalContextRef ctx = JSGlobalContextCreate(0);

    66         JSStringRef scriptRef = JSStringCreateWithUTF8CString(script);

    67 

    68         JSValueRef exception = 0;

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

    70         ASSERT(!exception);

    71 

    72         JSGarbageCollect(ctx);

    73         JSGlobalContextRelease(ctx);

    74         JSStringRelease(scriptRef);

    75         

    76         JSGarbageCollect(0);

    77 

    78         pthread_mutex_lock(&javaScriptThreadsMutex);

    79 

    80         // Check for cancellation.

    81         if (javaScriptThreadsShouldTerminate) {

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

    83             pthread_mutex_unlock(&javaScriptThreadsMutex);

    84             return 0;

    85         }

    86 

    87         // Respawn probabilistically.

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

    89             pthread_t pthread;

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

    91             pthread_detach(pthread);

    92 

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

    94             javaScriptThreads()->add(pthread);

    95 

    96             pthread_mutex_unlock(&javaScriptThreadsMutex);

    97             return 0;

    98         }

    99 

   100         pthread_mutex_unlock(&javaScriptThreadsMutex);

   101     }

   102 }

   103 

   104 void startJavaScriptThreads()

   105 {

   106     pthread_mutex_lock(&javaScriptThreadsMutex);

   107 

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

   109         pthread_t pthread;

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

   111         pthread_detach(pthread);

   112         javaScriptThreads()->add(pthread);

   113     }

   114 

   115     pthread_mutex_unlock(&javaScriptThreadsMutex);

   116 }

   117 

   118 void stopJavaScriptThreads()

   119 {

   120     pthread_mutex_lock(&javaScriptThreadsMutex);

   121 

   122     javaScriptThreadsShouldTerminate = true;

   123 

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

   125 

   126     pthread_mutex_unlock(&javaScriptThreadsMutex);

   127 

   128     while (true) {

   129         pthread_mutex_lock(&javaScriptThreadsMutex);

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

   131         pthread_mutex_unlock(&javaScriptThreadsMutex);

   132 

   133         if (!threadCount)

   134             break;

   135 

   136         usleep(1000);

   137     }

   138 }