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      1 /*
      2  * Copyright (C) 2009 Google Inc. All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions are
      6  * met:
      7  *
      8  *     * Redistributions of source code must retain the above copyright
      9  * notice, this list of conditions and the following disclaimer.
     10  *     * Redistributions in binary form must reproduce the above
     11  * copyright notice, this list of conditions and the following disclaimer
     12  * in the documentation and/or other materials provided with the
     13  * distribution.
     14  *     * Neither the name of Google Inc. nor the names of its
     15  * contributors may be used to endorse or promote products derived from
     16  * this software without specific prior written permission.
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     29  */
     30 
     31 #include "config.h"
     32 
     33 #if ENABLE(WORKERS)
     34 
     35 #include "ScriptExecutionContext.h"
     36 #include "SharedTimer.h"
     37 #include "ThreadGlobalData.h"
     38 #include "ThreadTimers.h"
     39 #include "WorkerRunLoop.h"
     40 #include "WorkerContext.h"
     41 #include "WorkerThread.h"
     42 
     43 namespace WebCore {
     44 
     45 class WorkerSharedTimer : public SharedTimer {
     46 public:
     47     WorkerSharedTimer()
     48         : m_sharedTimerFunction(0)
     49         , m_nextFireTime(0)
     50     {
     51     }
     52 
     53     // SharedTimer interface.
     54     virtual void setFiredFunction(void (*function)()) { m_sharedTimerFunction = function; }
     55     virtual void setFireTime(double fireTime) { m_nextFireTime = fireTime; }
     56     virtual void stop() { m_nextFireTime = 0; }
     57 
     58     bool isActive() { return m_sharedTimerFunction && m_nextFireTime; }
     59     double fireTime() { return m_nextFireTime; }
     60     void fire() { m_sharedTimerFunction(); }
     61 
     62 private:
     63     void (*m_sharedTimerFunction)();
     64     double m_nextFireTime;
     65 };
     66 
     67 class ModePredicate {
     68 public:
     69     ModePredicate(const String& mode)
     70         : m_mode(mode)
     71         , m_defaultMode(mode == WorkerRunLoop::defaultMode())
     72     {
     73     }
     74 
     75     bool isDefaultMode() const
     76     {
     77         return m_defaultMode;
     78     }
     79 
     80     bool operator()(WorkerRunLoop::Task* task) const
     81     {
     82         return m_defaultMode || m_mode == task->mode();
     83     }
     84 
     85 private:
     86     String m_mode;
     87     bool m_defaultMode;
     88 };
     89 
     90 WorkerRunLoop::WorkerRunLoop()
     91     : m_sharedTimer(new WorkerSharedTimer)
     92     , m_nestedCount(0)
     93     , m_uniqueId(0)
     94 {
     95 }
     96 
     97 WorkerRunLoop::~WorkerRunLoop()
     98 {
     99     ASSERT(!m_nestedCount);
    100 }
    101 
    102 String WorkerRunLoop::defaultMode()
    103 {
    104     return String();
    105 }
    106 
    107 class RunLoopSetup : public Noncopyable {
    108 public:
    109     RunLoopSetup(WorkerRunLoop& runLoop)
    110         : m_runLoop(runLoop)
    111     {
    112         if (!m_runLoop.m_nestedCount)
    113             threadGlobalData().threadTimers().setSharedTimer(m_runLoop.m_sharedTimer.get());
    114         m_runLoop.m_nestedCount++;
    115     }
    116 
    117     ~RunLoopSetup()
    118     {
    119         m_runLoop.m_nestedCount--;
    120         if (!m_runLoop.m_nestedCount)
    121             threadGlobalData().threadTimers().setSharedTimer(0);
    122     }
    123 private:
    124     WorkerRunLoop& m_runLoop;
    125 };
    126 
    127 void WorkerRunLoop::run(WorkerContext* context)
    128 {
    129     RunLoopSetup setup(*this);
    130     ModePredicate modePredicate(defaultMode());
    131     MessageQueueWaitResult result;
    132     do {
    133         result = runInMode(context, modePredicate);
    134     } while (result != MessageQueueTerminated);
    135 }
    136 
    137 MessageQueueWaitResult WorkerRunLoop::runInMode(WorkerContext* context, const String& mode)
    138 {
    139     RunLoopSetup setup(*this);
    140     ModePredicate modePredicate(mode);
    141     MessageQueueWaitResult result = runInMode(context, modePredicate);
    142     return result;
    143 }
    144 
    145 MessageQueueWaitResult WorkerRunLoop::runInMode(WorkerContext* context, const ModePredicate& predicate)
    146 {
    147     ASSERT(context);
    148     ASSERT(context->thread());
    149     ASSERT(context->thread()->threadID() == currentThread());
    150 
    151     double absoluteTime = (predicate.isDefaultMode() && m_sharedTimer->isActive()) ? m_sharedTimer->fireTime() : MessageQueue<Task>::infiniteTime();
    152     MessageQueueWaitResult result;
    153     OwnPtr<WorkerRunLoop::Task> task = m_messageQueue.waitForMessageFilteredWithTimeout(result, predicate, absoluteTime);
    154 
    155     // If the context is closing, don't execute any further JavaScript tasks (per section 4.1.1 of the Web Workers spec).  However, there may be implementation cleanup tasks in the queue, so keep running through it.
    156 
    157     switch (result) {
    158     case MessageQueueTerminated:
    159         break;
    160 
    161     case MessageQueueMessageReceived:
    162         task->performTask(context);
    163         break;
    164 
    165     case MessageQueueTimeout:
    166         if (!context->isClosing())
    167             m_sharedTimer->fire();
    168         break;
    169     }
    170 
    171     return result;
    172 }
    173 
    174 void WorkerRunLoop::terminate()
    175 {
    176     m_messageQueue.kill();
    177 }
    178 
    179 void WorkerRunLoop::postTask(PassOwnPtr<ScriptExecutionContext::Task> task)
    180 {
    181     postTaskForMode(task, defaultMode());
    182 }
    183 
    184 void WorkerRunLoop::postTaskForMode(PassOwnPtr<ScriptExecutionContext::Task> task, const String& mode)
    185 {
    186     m_messageQueue.append(Task::create(task, mode.crossThreadString()));
    187 }
    188 
    189 PassOwnPtr<WorkerRunLoop::Task> WorkerRunLoop::Task::create(PassOwnPtr<ScriptExecutionContext::Task> task, const String& mode)
    190 {
    191     return new Task(task, mode);
    192 }
    193 
    194 void WorkerRunLoop::Task::performTask(ScriptExecutionContext* context)
    195 {
    196     WorkerContext* workerContext = static_cast<WorkerContext *>(context);
    197     if (!workerContext->isClosing() || m_task->isCleanupTask())
    198         m_task->performTask(context);
    199 }
    200 
    201 WorkerRunLoop::Task::Task(PassOwnPtr<ScriptExecutionContext::Task> task, const String& mode)
    202     : m_task(task)
    203     , m_mode(mode.crossThreadString())
    204 {
    205 }
    206 
    207 
    208 } // namespace WebCore
    209 
    210 #endif // ENABLE(WORKERS)
    211