Change WokerThread to use a blink::WebThread.

Source/core/workers/WorkerThread.cpp

Index: Source/core/workers/WorkerThread.cpp
diff --git a/Source/core/workers/WorkerThread.cpp b/Source/core/workers/WorkerThread.cpp
index e84fd393fc20ee4a0c4a64870fcef6137b2950a7..100e9ed94021f9d1c5a37d4d0d19d7123eb66769 100644
--- a/Source/core/workers/WorkerThread.cpp
+++ b/Source/core/workers/WorkerThread.cpp
@@ -35,9 +35,12 @@
 #include "core/workers/WorkerReportingProxy.h"
 #include "core/workers/WorkerThreadStartupData.h"
 #include "platform/PlatformThreadData.h"
+#include "platform/Task.h"
+#include "platform/ThreadTimers.h"
 #include "platform/heap/ThreadState.h"
 #include "platform/weborigin/KURL.h"
 #include "public/platform/Platform.h"
+#include "public/platform/WebThread.h"
 #include "public/platform/WebWaitableEvent.h"
 #include "public/platform/WebWorkerRunLoop.h"
 #include "wtf/Noncopyable.h"
@@ -47,6 +50,11 @@
 
 namespace blink {
 
+namespace {
+const int64 kShortIdleHandlerDelayMs = 1000;
+const int64 kLongIdleHandlerDelayMs = 10*1000;
+}
+
 static Mutex& threadSetMutex()
 {
     AtomicallyInitializedStatic(Mutex&, mutex = *new Mutex);
@@ -65,8 +73,94 @@ unsigned WorkerThread::workerThreadCount()
     return workerThreads().size();
 }
 
+class WorkerSharedTimer : public SharedTimer {
+public:
+    explicit WorkerSharedTimer(blink::WebThread* webThread)
+        : m_thread(webThread)
+        , m_nextFireTime(0.0)
+    { }
+
+    virtual void setFiredFunction(blink::WebThread::SharedTimerFunction func)
+    {
+        m_thread->setSharedTimerFiredFunction(func);
+        if (!func)
+            m_nextFireTime = 0.0;
+    }
+    virtual void setFireInterval(double interval)
+    {
+        m_thread->setSharedTimerFireInterval(interval);
+        m_nextFireTime = interval + currentTime();
+    }
+    virtual void stop()
+    {
+        m_thread->stopSharedTimer();
+    }
+
+    double nextFireTime() { return m_nextFireTime; }
+
+private:
+    blink::WebThread* m_thread;
+    double m_nextFireTime;
+};
+
+class WorkerThreadTask : public blink::WebThread::Task {
+    WTF_MAKE_NONCOPYABLE(WorkerThreadTask); WTF_MAKE_FAST_ALLOCATED;
+public:
+    static PassOwnPtr<WorkerThreadTask> create(const WorkerThread& workerThread, PassOwnPtr<ExecutionContextTask> task, bool isInstrumented)
+    {
+        return adoptPtr(new WorkerThreadTask(workerThread, task, isInstrumented));
+    }
+
+    virtual ~WorkerThreadTask() { }
+
+    virtual void run() OVERRIDE
+    {
+        WorkerGlobalScope* workerGlobalScope = m_workerThread.workerGlobalScope();
+        if (m_isInstrumented)
+            InspectorInstrumentation::willPerformExecutionContextTask(workerGlobalScope, m_task.get());
+        if ((!workerGlobalScope->isClosing() && !m_workerThread.terminated()) || m_task->isCleanupTask())
+            m_task->performTask(workerGlobalScope);
+        if (m_isInstrumented)
+            InspectorInstrumentation::didPerformExecutionContextTask(workerGlobalScope);
+    }
+
+private:
+    WorkerThreadTask(const WorkerThread& workerThread, PassOwnPtr<ExecutionContextTask> task, bool isInstrumented)
+        : m_workerThread(workerThread)
+        , m_task(task)
+        , m_isInstrumented(isInstrumented)
+    {
+        if (m_isInstrumented)
+            m_isInstrumented = !m_task->taskNameForInstrumentation().isEmpty();
+        if (m_isInstrumented)
+            InspectorInstrumentation::didPostExecutionContextTask(m_workerThread.workerGlobalScope(), m_task.get());
+    }
+
+    const WorkerThread& m_workerThread;
+    OwnPtr<ExecutionContextTask> m_task;
+    bool m_isInstrumented;
+};
+
+class RunDebuggerQueueTask FINAL : public ExecutionContextTask {
+public:
+    static PassOwnPtr<RunDebuggerQueueTask> create(WorkerThread* thread)
+    {
+        return adoptPtr(new RunDebuggerQueueTask(thread));
+    }
+    virtual void performTask(ExecutionContext* context) OVERRIDE
+    {
+        ASSERT(context->isWorkerGlobalScope());
+        m_thread->runDebuggerTask(WorkerThread::DontWaitForMessage);
+    }
+
+private:
+    explicit RunDebuggerQueueTask(WorkerThread* thread) : m_thread(thread) { }
+
+    WorkerThread* m_thread;
+};
+
 WorkerThread::WorkerThread(WorkerLoaderProxy& workerLoaderProxy, WorkerReportingProxy& workerReportingProxy, PassOwnPtrWillBeRawPtr<WorkerThreadStartupData> startupData)
-    : m_threadID(0)
+    : m_terminated(false)
     , m_workerLoaderProxy(workerLoaderProxy)
     , m_workerReportingProxy(workerReportingProxy)
     , m_startupData(startupData)
@@ -83,25 +177,17 @@ WorkerThread::~WorkerThread()
     workerThreads().remove(this);
 }
 
-bool WorkerThread::start()
+void WorkerThread::start()
 {
-    // Mutex protection is necessary to ensure that m_threadID is initialized when the thread starts.
-    MutexLocker lock(m_threadCreationMutex);
-
-    if (m_threadID)
-        return true;
-
-    m_threadID = createThread(WorkerThread::workerThreadStart, this, "WebCore: Worker");
-
-    return m_threadID;
-}
+    if (m_thread)
+        return;
 
-void WorkerThread::workerThreadStart(void* thread)
-{
-    static_cast<WorkerThread*>(thread)->workerThread();
+    m_thread = adoptPtr(blink::Platform::current()->createThread("WebCore: Worker"));
+    m_sharedTimer = adoptPtr(new WorkerSharedTimer(m_thread.get()));
+    m_thread->postTask(new Task(WTF::bind(&WorkerThread::initialize, this)));
 }
 
-void WorkerThread::workerThread()
+void WorkerThread::initialize()
 {
     KURL scriptURL = m_startupData->m_scriptURL;
     String sourceCode = m_startupData->m_sourceCode;
@@ -109,19 +195,22 @@ void WorkerThread::workerThread()
 
     {
         MutexLocker lock(m_threadCreationMutex);
+
         ThreadState::attach();
         m_workerGlobalScope = createWorkerGlobalScope(m_startupData.release());
-        m_runLoop.setWorkerGlobalScope(workerGlobalScope());
 
-        if (m_runLoop.terminated()) {
+        PlatformThreadData::current().threadTimers().setSharedTimer(m_sharedTimer.get());
+
+        if (m_terminated) {
             // The worker was terminated before the thread had a chance to run. Since the context didn't exist yet,
             // forbidExecution() couldn't be called from stop().
             m_workerGlobalScope->script()->forbidExecution();
         }
     }
-    // The corresponding call to didStopWorkerRunLoop is in
+
+    // The corresponding call to didStopWorkerThread is in
     // ~WorkerScriptController.
-    blink::Platform::current()->didStartWorkerRunLoop(blink::WebWorkerRunLoop(&m_runLoop));
+    blink::Platform::current()->didStartWorkerThread(m_thread.get());
 
     // Notify proxy that a new WorkerGlobalScope has been created and started.
     m_workerReportingProxy.workerGlobalScopeStarted(m_workerGlobalScope.get());
@@ -132,13 +221,19 @@ void WorkerThread::workerThread()
     InspectorInstrumentation::willEvaluateWorkerScript(workerGlobalScope(), startMode);
     script->evaluate(ScriptSourceCode(sourceCode, scriptURL));
 
-    runEventLoop();
+    postInitialize();
+
+    m_weakFactory = adoptPtr(new WeakPtrFactory<WorkerThread>(this));
+    m_thread->postDelayedTask(new Task(WTF::bind(&WorkerThread::idleHandler, m_weakFactory->createWeakPtr())), kShortIdleHandlerDelayMs);
+}
+
+void WorkerThread::cleanup()
+{
+    m_weakFactory.release();
 
     // This should be called before we start the shutdown procedure.
     workerReportingProxy().willDestroyWorkerGlobalScope();
 
-    ThreadIdentifier threadID = m_threadID;
-
     // The below assignment will destroy the context, which will in turn notify messaging proxy.
     // We cannot let any objects survive past thread exit, because no other thread will run GC or otherwise destroy them.
     // If Oilpan is enabled, we detach of the context/global scope, with the final heap cleanup below sweeping it out.
@@ -165,14 +260,10 @@ void WorkerThread::workerThread()
     // Clean up PlatformThreadData before WTF::WTFThreadData goes away!
     PlatformThreadData::current().destroy();
 
-    // The thread object may be already destroyed from notification now, don't try to access "this".
-    detachThread(threadID);
-}
-
-void WorkerThread::runEventLoop()
-{
-    // Does not return until terminated.
-    m_runLoop.run();
+    // Set the timer function to null, which will cause the shared timer in
+    // WebThread to be deleted. It is important to do it here, since it
+    // should be deleted on the same thread that it executes on.
+    m_sharedTimer->setFiredFunction(0);
 }
 
 class WorkerThreadShutdownFinishTask : public ExecutionContextTask {
@@ -188,6 +279,7 @@ public:
         workerGlobalScope->clearInspector();
         // It's not safe to call clearScript until all the cleanup tasks posted by functions initiated by WorkerThreadShutdownStartTask have completed.
         workerGlobalScope->clearScript();
+        workerGlobalScope->thread()->webThread()->postTask(new Task(WTF::bind(&WorkerThread::cleanup, workerGlobalScope->thread())));
     }
 
     virtual bool isCleanupTask() const { return true; }
@@ -205,6 +297,7 @@ public:
         WorkerGlobalScope* workerGlobalScope = toWorkerGlobalScope(context);
         workerGlobalScope->stopFetch();
         workerGlobalScope->stopActiveDOMObjects();
+        workerGlobalScope->thread()->webThread()->stopSharedTimer();
 
         // Event listeners would keep DOMWrapperWorld objects alive for too long. Also, they have references to JS objects,
         // which become dangling once Heap is destroyed.
@@ -223,9 +316,13 @@ void WorkerThread::stop()
     // Prevent the deadlock between GC and an attempt to stop a thread.
     ThreadState::SafePointScope safePointScope(ThreadState::HeapPointersOnStack);
 
-    // Mutex protection is necessary because stop() can be called before the context is fully created.
+    // Protect against this method and initialize() racing each other.
     MutexLocker lock(m_threadCreationMutex);
 
+    // If stop has already been called, just return.
+    if (m_terminated)
+        return;
+
     // Signal the thread to notify that the thread's stopping.
     if (m_shutdownEvent)
         m_shutdownEvent->signal();
@@ -234,30 +331,77 @@ void WorkerThread::stop()
     if (m_workerGlobalScope) {
         m_workerGlobalScope->script()->scheduleExecutionTermination();
         m_workerGlobalScope->wasRequestedToTerminate();
-        m_runLoop.postTaskAndTerminate(WorkerThreadShutdownStartTask::create());
+        InspectorInstrumentation::didKillAllExecutionContextTasks(m_workerGlobalScope.get());

[aandrey, 2014/07/24 16:07:53]

is it safe to access m_workerGlobalScope here?
if not, just move this line upwards, before calling
m_workerGlobalScope->wasRequestedToTerminate()

[nasko, 2014/07/25 06:30:14]

It is safe. It is used further in the WorkerThreadShutdownStartTask,
WorkerThreadShutdownFinishTask, and finally disposed in ::cleanup(). Therefore
the line can be earlier or later, whichever is best. I opted to keep it somewhat
equivalent to where it was called prior to my patch.

[yurys, 2014/07/25 06:41:56]

It is unsafe to access m_workerGlobalScope here as WorkerThread::stop() is
called on the main thread while m_workerGlobalScope is cleared in
WorkerThread::cleanup which is executed on the worker thread without acquiring a
mutex.

+        postTask(WorkerThreadShutdownStartTask::create());
+        m_terminated = true;
         return;
     }
-    m_runLoop.terminate();
 }
 
 bool WorkerThread::isCurrentThread() const
 {
-    return m_threadID == currentThread();
+    return m_thread && m_thread->isCurrentThread();
+}
+
+void WorkerThread::idleHandler()
+{
+    if (m_terminated)
+        return;
+
+    int64 delay = kLongIdleHandlerDelayMs;
+
+    // Do a script engine idle notification if the next event is distant enough.
+    const double kMinIdleTimespan = 0.3;
+    if (!m_sharedTimer->nextFireTime() || m_sharedTimer->nextFireTime() > currentTime() + kMinIdleTimespan) {
+        bool hasMoreWork = !m_workerGlobalScope->idleNotification();
+        if (hasMoreWork)
+            delay = kShortIdleHandlerDelayMs;
+    }
+
+    m_thread->postDelayedTask(new Task(WTF::bind(&WorkerThread::idleHandler, m_weakFactory->createWeakPtr())), delay);
 }
 
 void WorkerThread::postTask(PassOwnPtr<ExecutionContextTask> task)
 {
-    m_runLoop.postTask(task);
+    m_thread->postTask(WorkerThreadTask::create(*this, task, true).leakPtr());
 }
 
 void WorkerThread::postDebuggerTask(PassOwnPtr<ExecutionContextTask> task)
 {
-    m_runLoop.postDebuggerTask(task);
+    m_debuggerMessageQueue.append(WorkerThreadTask::create(*this, task, false));
+    postTask(RunDebuggerQueueTask::create(this));
+}
+
+MessageQueueWaitResult WorkerThread::runDebuggerTask(WaitMode waitMode)
+{
+    ASSERT(isCurrentThread());
+    MessageQueueWaitResult result;
+    double absoluteTime = MessageQueue<blink::WebThread::Task>::infiniteTime();
+    OwnPtr<blink::WebThread::Task> task;
+    {
+        if (waitMode == DontWaitForMessage)
+            absoluteTime = 0.0;
+        ThreadState::SafePointScope safePointScope(ThreadState::NoHeapPointersOnStack);
+        task = m_debuggerMessageQueue.waitForMessageWithTimeout(result, absoluteTime);
+    }
+
+    if (result == MessageQueueMessageReceived) {
+        InspectorInstrumentation::willProcessTask(workerGlobalScope());
+        task->run();
+        InspectorInstrumentation::didProcessTask(workerGlobalScope());
+    }
+
+    return result;
+}
+
+void WorkerThread::willEnterNestedLoop()
+{
+    InspectorInstrumentation::willEnterNestedRunLoop(m_workerGlobalScope.get());
 }
 
-MessageQueueWaitResult WorkerThread::runDebuggerTask(WorkerRunLoop::WaitMode waitMode)
+void WorkerThread::didLeaveNestedLoop()
 {
-    return m_runLoop.runDebuggerTask(waitMode);
+    InspectorInstrumentation::didLeaveNestedRunLoop(m_workerGlobalScope.get());
 }
 
 } // namespace blink