void V8WorkerGlobalScopeEventListener::handleEvent(ExecutionContext* context, Event* event)
{
    if (!context)
        return;

    // The callback function on XMLHttpRequest can clear the event listener and destroys 'this' object. Keep a local reference to it.
    // See issue 889829.
    RefPtr<V8AbstractEventListener> protect(this);

    v8::Isolate* isolate = toIsolate(context);
    v8::HandleScope handleScope(isolate);

    WorkerScriptController* script = toWorkerGlobalScope(context)->script();
    if (!script)
        return;

    v8::Handle<v8::Context> v8Context = script->context();
    if (v8Context.IsEmpty())
        return;

    // Enter the V8 context in which to perform the event handling.
    v8::Context::Scope scope(v8Context);

    // Get the V8 wrapper for the event object.
    v8::Handle<v8::Value> jsEvent = toV8(event, v8::Handle<v8::Object>(), isolate);

    invokeEventHandler(context, event, v8::Local<v8::Value>::New(isolate, jsEvent));
}

// static
WorkerContextProxy* WebWorkerClientImpl::createWorkerContextProxy(Worker* worker)
{
    // Special behavior for multiple workers per process.
    // FIXME: v8 doesn't support more than one workers per process.
    // if (!worker->scriptExecutionContext()->isDocument())
    //     return new WorkerMessagingProxy(worker);

    WebWorker* webWorker = 0;
    WebWorkerClientImpl* proxy = new WebWorkerClientImpl(worker);

    if (worker->scriptExecutionContext()->isDocument()) {
        Document* document = static_cast<Document*>(
            worker->scriptExecutionContext());
        WebFrameImpl* webFrame = WebFrameImpl::fromFrame(document->frame());
        webWorker = webFrame->client()->createWorker(webFrame, proxy);
    } else {
        WorkerScriptController* controller = WorkerScriptController::controllerForContext();
        if (!controller) {
            ASSERT_NOT_REACHED();
            return 0;
        }

        DedicatedWorkerThread* thread = static_cast<DedicatedWorkerThread*>(controller->workerContext()->thread());
        WorkerObjectProxy* workerObjectProxy = &thread->workerObjectProxy();
        WebWorkerImpl* impl = reinterpret_cast<WebWorkerImpl*>(workerObjectProxy);
        webWorker = impl->client()->createWorker(proxy);
    }

    proxy->setWebWorker(webWorker);
    return proxy;
}

void V8WorkerContextEventListener::handleEvent(ScriptExecutionContext* context, Event* event)
{
    if (!context)
        return;

    // The callback function on XMLHttpRequest can clear the event listener and destroys 'this' object. Keep a local reference to it.
    // See issue 889829.
    RefPtr<V8AbstractEventListener> protect(this);

    v8::HandleScope handleScope;

    ASSERT(context->isWorkerContext());
    WorkerScriptController* script = static_cast<WorkerContext*>(context)->script();
    if (!script)
        return;

    v8::Handle<v8::Context> v8Context = script->context();
    if (v8Context.IsEmpty())
        return;

    // Enter the V8 context in which to perform the event handling.
    v8::Context::Scope scope(v8Context);

    // Get the V8 wrapper for the event object.
    v8::Handle<v8::Value> jsEvent = toV8(event);

    invokeEventHandler(context, event, jsEvent);
}

void* WorkerThread::workerThread()
{
    {
        MutexLocker lock(m_threadCreationMutex);
        m_workerContext = createWorkerContext(m_startupData->m_scriptURL, m_startupData->m_userAgent);

        if (m_runLoop.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_workerContext->script()->forbidExecution();
        }
    }

    WorkerScriptController* script = m_workerContext->script();
    script->evaluate(ScriptSourceCode(m_startupData->m_sourceCode, m_startupData->m_scriptURL));
    // Free the startup data to cause its member variable deref's happen on the worker's thread (since
    // all ref/derefs of these objects are happening on the thread at this point). Note that
    // WorkerThread::~WorkerThread happens on a different thread where it was created.
    m_startupData.clear();

    runEventLoop();

    ThreadIdentifier threadID = m_threadID;

    ASSERT(m_workerContext->hasOneRef());

    // 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.
    m_workerContext = 0;
    
    // The thread object may be already destroyed from notification now, don't try to access "this".
    detachThread(threadID);

    return 0;
}

 void executeScriptInWorker(WorkerThread* worker, WebWaitableEvent* waitEvent)
 {
     WorkerScriptController* scriptController = worker->workerGlobalScope()->script();
     bool evaluateResult = scriptController->evaluate(ScriptSourceCode("var counter = 0; ++counter;"));
     ASSERT_UNUSED(evaluateResult, evaluateResult);
     waitEvent->signal();
 }

bool ActiveDOMCallback::isScriptControllerTerminating() const
{
    ExecutionContext* context = executionContext();
    if (context && context->isWorkerGlobalScope()) {
        WorkerScriptController* scriptController = toWorkerGlobalScope(context)->script();
        if (!scriptController || scriptController->isExecutionForbidden() || scriptController->isExecutionTerminating())
            return true;
    }
    return false;
}

JSValue toJS(ExecState*, WorkerContext* workerContext)
{
    if (!workerContext)
        return jsNull();
    WorkerScriptController* script = workerContext->script();
    if (!script)
        return jsNull();
    JSWorkerContext* contextWrapper = script->workerContextWrapper();
    ASSERT(contextWrapper);
    return contextWrapper;
}

v8::Local<v8::Function> V8DOMWrapper::getConstructor(WrapperTypeInfo* type, WorkerContext*)
{
    WorkerScriptController* controller = WorkerScriptController::controllerForContext();
    WorkerContextExecutionProxy* proxy = controller ? controller->proxy() : 0;
    if (!proxy)
        return v8::Local<v8::Function>();

    v8::Handle<v8::Context> context = proxy->context();
    if (context.IsEmpty())
        return v8::Local<v8::Function>();

    return getConstructorForContext(type, context);
}

void WorkerThread::workerThread()
{
    // Propagate the mainThread's fenv to workers.
#if PLATFORM(IOS)
    FloatingPointEnvironment::singleton().propagateMainThreadEnvironment();
#endif

#if PLATFORM(GTK)
    GRefPtr<GMainContext> mainContext = adoptGRef(g_main_context_new());
    g_main_context_push_thread_default(mainContext.get());
#endif

    {
        LockHolder lock(m_threadCreationMutex);
        m_workerGlobalScope = createWorkerGlobalScope(m_startupData->m_scriptURL, m_startupData->m_userAgent, m_startupData->m_contentSecurityPolicyResponseHeaders, m_startupData->m_shouldBypassMainWorldContentSecurityPolicy, WTFMove(m_startupData->m_topOrigin));

        if (m_runLoop.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();
        }
    }

    WorkerScriptController* script = m_workerGlobalScope->script();
    script->evaluate(ScriptSourceCode(m_startupData->m_sourceCode, m_startupData->m_scriptURL));
    // Free the startup data to cause its member variable deref's happen on the worker's thread (since
    // all ref/derefs of these objects are happening on the thread at this point). Note that
    // WorkerThread::~WorkerThread happens on a different thread where it was created.
    m_startupData = nullptr;

    runEventLoop();

#if PLATFORM(GTK)
    g_main_context_pop_thread_default(mainContext.get());
#endif

    ThreadIdentifier threadID = m_threadID;

    ASSERT(m_workerGlobalScope->hasOneRef());

    // 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.
    m_workerGlobalScope = nullptr;

    // Clean up WebCore::ThreadGlobalData before WTF::WTFThreadData goes away!
    threadGlobalData().destroy();

    // The thread object may be already destroyed from notification now, don't try to access "this".
    detachThread(threadID);
}

v8::Handle<v8::Value> toV8(WorkerContext* impl, v8::Handle<v8::Object> creationContext, v8::Isolate* isolate)
{
    // Notice that we explicitly ignore creationContext because the WorkerContext is its own creationContext.

    if (!impl)
        return v8NullWithCheck(isolate);

    WorkerScriptController* script = impl->script();
    if (!script)
        return v8NullWithCheck(isolate);

    v8::Handle<v8::Object> global = script->context()->Global();
    ASSERT(!global.IsEmpty());
    return global;
}

void ScheduledAction::execute(WorkerContext* workerContext)
{
    // In a Worker, the execution should always happen on a worker thread.
    ASSERT(workerContext->thread()->threadID() == currentThread());

    WorkerScriptController* scriptController = workerContext->script();

    if (m_function) {
        JSWorkerContext* contextWrapper = scriptController->workerContextWrapper();
        executeFunctionInContext(contextWrapper, contextWrapper, workerContext);
    } else {
        ScriptSourceCode code(m_code, workerContext->url());
        scriptController->evaluate(code);
    }
}

void ScheduledAction::execute(WorkerContext* workerContext)
{
    // In a Worker, the execution should always happen on a worker thread.
    ASSERT(workerContext->thread()->threadID() == currentThread());
  
    WorkerScriptController* scriptController = workerContext->script();

    if (!m_function.IsEmpty() && m_function->IsFunction()) {
        v8::HandleScope handleScope;
        v8::Handle<v8::Context> v8Context = v8::Local<v8::Context>::New(m_context.get());
        ASSERT(!v8Context.IsEmpty());
        v8::Context::Scope scope(v8Context);
        m_function->Call(v8Context->Global(), m_argc, m_argv);
    } else
        scriptController->evaluate(m_code);
}

void WebWorkerBase::openFileSystem(WebFileSystem::Type type, long long size, WebFileSystemCallbacks* callbacks, bool synchronous)
{
    WorkerRunLoop& runLoop = m_workerThread->runLoop();
    WorkerScriptController* controller = WorkerScriptController::controllerForContext();
    WorkerContext* workerContext = controller->workerContext();

    // Create a unique mode for this openFileSystem call.
    String mode = openFileSystemMode;
    mode.append(String::number(runLoop.createUniqueId()));

    RefPtr<WorkerFileSystemCallbacksBridge> bridge = WorkerFileSystemCallbacksBridge::create(this, workerContext, callbacks);
    bridge->postOpenFileSystemToMainThread(commonClient(), type, size, mode);

    if (synchronous) {
        if (runLoop.runInMode(workerContext, mode) == MessageQueueTerminated)
            bridge->stop();
    }
}

void WorkerThread::workerThread()
{
    // Propagate the mainThread's fenv to workers.
#if PLATFORM(IOS)
    fesetenv(&mainThreadFEnv);
#endif

    {
        MutexLocker lock(m_threadCreationMutex);
        m_workerGlobalScope = createWorkerGlobalScope(m_startupData->m_scriptURL, m_startupData->m_userAgent, std::move(m_startupData->m_groupSettings), m_startupData->m_contentSecurityPolicy, m_startupData->m_contentSecurityPolicyType, m_startupData->m_topOrigin.release());

        if (m_runLoop.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();
        }
    }

    WorkerScriptController* script = m_workerGlobalScope->script();
#if ENABLE(INSPECTOR)
    InspectorInstrumentation::willEvaluateWorkerScript(workerGlobalScope(), m_startupData->m_startMode);
#endif
    script->evaluate(ScriptSourceCode(m_startupData->m_sourceCode, m_startupData->m_scriptURL));
    // Free the startup data to cause its member variable deref's happen on the worker's thread (since
    // all ref/derefs of these objects are happening on the thread at this point). Note that
    // WorkerThread::~WorkerThread happens on a different thread where it was created.
    m_startupData.clear();

    runEventLoop();

    ThreadIdentifier threadID = m_threadID;

    ASSERT(m_workerGlobalScope->hasOneRef());

    // 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.
    m_workerGlobalScope = 0;

    // Clean up WebCore::ThreadGlobalData before WTF::WTFThreadData goes away!
    threadGlobalData().destroy();

    // The thread object may be already destroyed from notification now, don't try to access "this".
    detachThread(threadID);
}

static void promiseRejectHandlerInWorker(v8::PromiseRejectMessage data)
{
    v8::Local<v8::Promise> promise = data.GetPromise();

    // Bail out if called during context initialization.
    v8::Isolate* isolate = promise->GetIsolate();
    ScriptState* scriptState = ScriptState::current(isolate);
    if (!scriptState->contextIsValid())
        return;

    ExecutionContext* executionContext = scriptState->executionContext();
    if (!executionContext)
        return;

    ASSERT(executionContext->isWorkerGlobalScope());
    WorkerScriptController* scriptController = toWorkerGlobalScope(executionContext)->script();
    ASSERT(scriptController);

    if (data.GetEvent() == v8::kPromiseHandlerAddedAfterReject) {
        scriptController->rejectedPromises()->handlerAdded(data);
        return;
    }

    ASSERT(data.GetEvent() == v8::kPromiseRejectWithNoHandler);

    int scriptId = 0;
    int lineNumber = 0;
    int columnNumber = 0;
    String resourceName;
    String errorMessage;

    v8::Local<v8::Message> message = v8::Exception::CreateMessage(data.GetValue());
    if (!message.IsEmpty()) {
        TOSTRING_VOID(V8StringResource<>, resourceName, message->GetScriptOrigin().ResourceName());
        scriptId = message->GetScriptOrigin().ScriptID()->Value();
        if (v8Call(message->GetLineNumber(scriptState->context()), lineNumber)
            && v8Call(message->GetStartColumn(scriptState->context()), columnNumber))
            ++columnNumber;
        // message->Get() can be empty here. https://crbug.com/450330
        errorMessage = toCoreStringWithNullCheck(message->Get());
    }
    scriptController->rejectedPromises()->rejectedWithNoHandler(scriptState, data, errorMessage, resourceName, scriptId, lineNumber, columnNumber, nullptr);
}

v8::Handle<v8::Value> SetTimeoutOrInterval(const v8::Arguments& args, bool singleShot)
{
    WorkerContext* workerContext = V8WorkerContext::toNative(args.Holder());

    int argumentCount = args.Length();
    if (argumentCount < 1)
        return v8::Undefined();

    v8::Handle<v8::Value> function = args[0];
    int32_t timeout = argumentCount >= 2 ? args[1]->Int32Value() : 0;
    int timerId;

    WorkerScriptController* script = workerContext->script();
    if (!script)
        return v8::Undefined();

    v8::Handle<v8::Context> v8Context = script->context();
    if (function->IsString()) {
        if (ContentSecurityPolicy* policy = workerContext->contentSecurityPolicy()) {
            if (!policy->allowEval())
                return v8Integer(0, args.GetIsolate());
        }
        WTF::String stringFunction = toWebCoreString(function);
        timerId = DOMTimer::install(workerContext, adoptPtr(new ScheduledAction(v8Context, stringFunction, workerContext->url())), timeout, singleShot);
    } else if (function->IsFunction()) {
        size_t paramCount = argumentCount >= 2 ? argumentCount - 2 : 0;
        v8::Local<v8::Value>* params = 0;
        if (paramCount > 0) {
            params = new v8::Local<v8::Value>[paramCount];
            for (size_t i = 0; i < paramCount; ++i)
                params[i] = args[i+2];
        }
        // ScheduledAction takes ownership of actual params and releases them in its destructor.
        OwnPtr<ScheduledAction> action = adoptPtr(new ScheduledAction(v8Context, v8::Handle<v8::Function>::Cast(function), paramCount, params));
        // FIXME: We should use a OwnArrayPtr for params.
        delete [] params;
        timerId = DOMTimer::install(workerContext, action.release(), timeout, singleShot);
    } else
        return v8::Undefined();

    return v8Integer(timerId, args.GetIsolate());
}

bool WebWorkerBase::allowDatabase(WebFrame*, const WebString& name, const WebString& displayName, unsigned long estimatedSize)
{
    WorkerRunLoop& runLoop = m_workerThread->runLoop();
    WorkerScriptController* controller = WorkerScriptController::controllerForContext();
    WorkerContext* workerContext = controller->workerContext();

    // Create a unique mode just for this synchronous call.
    String mode = allowDatabaseMode;
    mode.append(String::number(runLoop.createUniqueId()));

    RefPtr<AllowDatabaseMainThreadBridge> bridge = AllowDatabaseMainThreadBridge::create(this, mode, commonClient(), m_webView->mainFrame(), String(name), String(displayName), estimatedSize);

    // Either the bridge returns, or the queue gets terminated.
    if (runLoop.runInMode(workerContext, mode) == MessageQueueTerminated) {
        bridge->cancel();
        return false;
    }

    return bridge->result();
}

v8::Local<v8::Function> V8DOMWrapper::constructorForType(WrapperTypeInfo* type, WorkerContext*)
{
    WorkerScriptController* controller = WorkerScriptController::controllerForContext();
    WorkerContextExecutionProxy* proxy = controller ? controller->proxy() : 0;
    return proxy ? proxy->perContextData()->constructorForType(type) : v8::Local<v8::Function>();
}