compositor-worker: Refactor CompositorWorkerManager

third_party/WebKit/Source/modules/compositorworker/CompositorWorkerThread.cpp

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "modules/compositorworker/CompositorWorkerThread.h"
 
+#include "bindings/core/v8/V8GCController.h"
 #include "bindings/core/v8/V8Initializer.h"
 #include "core/workers/WorkerObjectProxy.h"
 #include "core/workers/WorkerThreadStartupData.h"
 #include "modules/compositorworker/CompositorWorkerGlobalScope.h"
-#include "modules/compositorworker/CompositorWorkerManager.h"
+#include "platform/ThreadSafeFunctional.h"
+#include "platform/TraceEvent.h"
 #include "public/platform/Platform.h"
 
 namespace blink {
 
+namespace {
+
+class CompositorWorkerSharedState {
+public:
+    static CompositorWorkerSharedState& instance()
+    {
+        AtomicallyInitializedStaticReference(CompositorWorkerSharedState, compositorWorkerSharedState, (new CompositorWorkerSharedState()));
+        return compositorWorkerSharedState;
+    }
+
+    WebThreadSupportingGC* compositorWorkerThread()
+    {
+        MutexLocker lock(m_mutex);
+        if (!m_thread && isMainThread()) {
+            ASSERT(!m_workerCount);
+            WebThread* platformThread = Platform::current()->compositorThread();
+            m_thread = WebThreadSupportingGC::createForThread(platformThread);
+        }
+        return m_thread.get();
+    }
+
+    void initializeBackingThread()
+    {
+        MutexLocker lock(m_mutex);
+        ASSERT(m_thread->isCurrentThread());
+        ++m_workerCount;
+        if (m_workerCount > 1)
+            return;
+
+        m_thread->initialize();
+
+        // Initialize the isolate at the same time.
+        ASSERT(!m_isolate);
+        m_isolate = V8PerIsolateData::initialize();
+        V8Initializer::initializeWorker(m_isolate);
+
+        OwnPtr<V8IsolateInterruptor> interruptor = adoptPtr(new V8IsolateInterruptor(m_isolate));
+        ThreadState::current()->addInterruptor(interruptor.release());
+        ThreadState::current()->registerTraceDOMWrappers(m_isolate, V8GCController::traceDOMWrappers);
+    }
+
+    void shutdownBackingThread(const CompositorWorkerThread* worker)
+    {
+        MutexLocker lock(m_mutex);
+        ASSERT(m_thread->isCurrentThread());
+        ASSERT(m_workerCount > 0);
+        --m_workerCount;
+        if (m_workerCount == 0) {
+            m_thread->shutdown();
+            m_markedForDeletion.set(worker, m_thread.release());
+        }
+    }
+
+    void willDestroyWorkerThread(const CompositorWorkerThread* worker)
+    {
+        MutexLocker lock(m_mutex);
+        m_markedForDeletion.remove(worker);
+    }
+
+    v8::Isolate* initializeIsolate()
+    {
+        MutexLocker lock(m_mutex);
+        ASSERT(m_thread->isCurrentThread());
+        ASSERT(m_isolate);
+        // It is safe to use the existing isolate even if TerminateExecution() has been
+        // called on it, without calling CancelTerminateExecution().
+        return m_isolate;
+    }
+
+    void willDestroyIsolate()
+    {
+        MutexLocker lock(m_mutex);
+        ASSERT(m_thread->isCurrentThread());
+        if (m_workerCount == 1)
+            V8PerIsolateData::willBeDestroyed(m_isolate);
+    }
+
+    void destroyIsolate()
+    {
+        MutexLocker lock(m_mutex);
+        if (!m_thread) {
+            ASSERT(m_workerCount == 0);
+            V8PerIsolateData::destroy(m_isolate);
+            m_isolate = nullptr;
+        }
+    }
+
+    void terminateV8Execution()
+    {
+        MutexLocker lock(m_mutex);
+        ASSERT(isMainThread());
+        if (m_workerCount > 1)
+            return;
+
+        v8::V8::TerminateExecution(m_isolate);
+    }
+
+    bool hasThreadForTest()
+    {
+        return m_thread;
+    }
+
+    bool hasIsolateForTest()
+    {
+        return m_isolate;
+    }
+
+private:
+    CompositorWorkerSharedState() {}
+    ~CompositorWorkerSharedState() {}
+
+    Mutex m_mutex;
+    OwnPtr<WebThreadSupportingGC> m_thread;
+    int m_workerCount = 0;
+    v8::Isolate* m_isolate = nullptr;
+
+    // You may only use this collection while holding the mutex.
+    HashMap<const CompositorWorkerThread*, OwnPtr<WebThreadSupportingGC>> m_markedForDeletion;

[haraken, 2015/12/03 04:04:21]

Why do we need the m_markedForDeletion? Wouldn't it be enough to just call
m_thread.clear() in ~CompositorWorkerThread()?

In the first place, I don't fully understand why your previous CL caused a hang.
It is true that WebThreadSupportingGC's destructor blocks until all tasks in the
worker queue has been processed, but why can that cause a hang in this case?

+};
+
+} // namespace
+
 PassRefPtr<CompositorWorkerThread> CompositorWorkerThread::create(PassRefPtr<WorkerLoaderProxy> workerLoaderProxy, WorkerObjectProxy& workerObjectProxy, double timeOrigin)
 {
+    TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("compositor-worker"), "CompositorWorkerThread::create");
     ASSERT(isMainThread());
     return adoptRef(new CompositorWorkerThread(workerLoaderProxy, workerObjectProxy, timeOrigin));
 }
 
 CompositorWorkerThread::CompositorWorkerThread(PassRefPtr<WorkerLoaderProxy> workerLoaderProxy, WorkerObjectProxy& workerObjectProxy, double timeOrigin)
     : WorkerThread(workerLoaderProxy, workerObjectProxy)
     , m_workerObjectProxy(workerObjectProxy)
     , m_timeOrigin(timeOrigin)
 {
 }
 
 CompositorWorkerThread::~CompositorWorkerThread()
 {
+    CompositorWorkerSharedState::instance().willDestroyWorkerThread(this);
+}
+
+WebThreadSupportingGC* CompositorWorkerThread::sharedBackingThread()
+{
+    return CompositorWorkerSharedState::instance().compositorWorkerThread();
 }
 
 PassRefPtrWillBeRawPtr<WorkerGlobalScope> CompositorWorkerThread::createWorkerGlobalScope(PassOwnPtr<WorkerThreadStartupData> startupData)
 {
+    TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("compositor-worker"), "CompositorWorkerThread::createWorkerGlobalScope");
     return CompositorWorkerGlobalScope::create(this, startupData, m_timeOrigin);
 }
 
 WebThreadSupportingGC& CompositorWorkerThread::backingThread()
 {
-    return CompositorWorkerManager::instance()->compositorWorkerThread();
+    return *CompositorWorkerSharedState::instance().compositorWorkerThread();
 }
 
 void CompositorWorkerThread::initializeBackingThread()
 {
-    CompositorWorkerManager::instance()->initializeBackingThread();
+    TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("compositor-worker"), "CompositorWorkerThread::initializeBackingThread");
+    CompositorWorkerSharedState::instance().initializeBackingThread();
 }
 
 void CompositorWorkerThread::shutdownBackingThread()
 {
-    CompositorWorkerManager::instance()->shutdownBackingThread();
+    TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("compositor-worker"), "CompositorWorkerThread::shutdownBackingThread");
+    CompositorWorkerSharedState::instance().shutdownBackingThread(this);
 }
 
 v8::Isolate* CompositorWorkerThread::initializeIsolate()
 {
-    return CompositorWorkerManager::instance()->initializeIsolate();
+    return CompositorWorkerSharedState::instance().initializeIsolate();
 }
 
 void CompositorWorkerThread::willDestroyIsolate()
 {
-    CompositorWorkerManager::instance()->willDestroyIsolate();
+    TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("compositor-worker"), "CompositorWorkerThread::willDestroyIsolate");
+    CompositorWorkerSharedState::instance().willDestroyIsolate();
 }
 
 void CompositorWorkerThread::destroyIsolate()
 {
-    CompositorWorkerManager::instance()->destroyIsolate();
+    TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("compositor-worker"), "CompositorWorkerThread::destroyIsolate");
+    CompositorWorkerSharedState::instance().destroyIsolate();
 }
 
 void CompositorWorkerThread::terminateV8Execution()
 {
-    CompositorWorkerManager::instance()->terminateV8Execution();
+    TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("compositor-worker"), "CompositorWorkerThread::terminateV8Execution");
+    CompositorWorkerSharedState::instance().terminateV8Execution();
+}
+
+bool CompositorWorkerThread::hasThreadForTest()
+{
+    return CompositorWorkerSharedState::instance().hasThreadForTest();
+}
+
+bool CompositorWorkerThread::hasIsolateForTest()
+{
+    return CompositorWorkerSharedState::instance().hasIsolateForTest();
 }
 
 } // namespace blink