/*
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 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
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 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
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#include "config.h"

#include "bindings/core/v8/WorkerScriptController.h"

#include "bindings/core/v8/ScriptSourceCode.h"
#include "bindings/core/v8/ScriptValue.h"
#include "bindings/core/v8/V8DedicatedWorkerGlobalScope.h"
#include "bindings/core/v8/V8ErrorHandler.h"
#include "bindings/core/v8/V8GCController.h"
#include "bindings/core/v8/V8Initializer.h"
#include "bindings/core/v8/V8ObjectConstructor.h"
#include "bindings/core/v8/V8ScriptRunner.h"
#include "bindings/core/v8/V8SharedWorkerGlobalScope.h"
#include "bindings/core/v8/V8WorkerGlobalScope.h"
#include "bindings/core/v8/WrapperTypeInfo.h"
#include "bindings/modules/v8/V8ServiceWorkerGlobalScope.h"
#include "core/events/ErrorEvent.h"
#include "core/frame/DOMTimer.h"
#include "core/inspector/ScriptCallStack.h"
#include "core/workers/SharedWorkerGlobalScope.h"
#include "core/workers/WorkerGlobalScope.h"
#include "core/workers/WorkerObjectProxy.h"
#include "core/workers/WorkerThread.h"
#include "platform/heap/ThreadState.h"
#include "public/platform/Platform.h"
#include "public/platform/WebWorkerRunLoop.h"
#include <v8.h>

namespace blink {

class WorkerScriptController::WorkerGlobalScopeExecutionState FINAL {
    STACK_ALLOCATED();
public:
    explicit WorkerGlobalScopeExecutionState(WorkerScriptController* controller)
        : hadException(false)
        , lineNumber(0)
        , columnNumber(0)
        , m_controller(controller)
        , m_outerState(controller->m_globalScopeExecutionState)
    {
        m_controller->m_globalScopeExecutionState = this;
    }

    ~WorkerGlobalScopeExecutionState()
    {
        m_controller->m_globalScopeExecutionState = m_outerState;
    }

    void trace(Visitor* visitor)
    {
        visitor->trace(m_errorEventFromImportedScript);
    }

    bool hadException;
    String errorMessage;
    int lineNumber;
    int columnNumber;
    String sourceURL;
    ScriptValue exception;
    RefPtrWillBeMember<ErrorEvent> m_errorEventFromImportedScript;

    // A WorkerGlobalScopeExecutionState context is stack allocated by
    // WorkerScriptController::evaluate(), with the contoller using it
    // during script evaluation. To handle nested evaluate() uses,
    // WorkerGlobalScopeExecutionStates are chained together;
    // |m_outerState| keeps a pointer to the context object one level out
    // (or 0, if outermost.) Upon return from evaluate(), the
    // WorkerScriptController's WorkerGlobalScopeExecutionState is popped
    // and the previous one restored (see above dtor.)
    //
    // With Oilpan, |m_outerState| isn't traced. It'll be "up the stack"
    // and its fields will be traced when scanning the stack.
    WorkerScriptController* m_controller;
    WorkerGlobalScopeExecutionState* m_outerState;
};

WorkerScriptController::WorkerScriptController(WorkerGlobalScope& workerGlobalScope)
    : m_isolate(v8::Isolate::New())
    , m_workerGlobalScope(workerGlobalScope)
    , m_executionForbidden(false)
    , m_executionScheduledToTerminate(false)
    , m_globalScopeExecutionState(0)
{
    m_isolate->Enter();
    V8Initializer::initializeWorker(m_isolate);
    v8::V8::Initialize();
    V8PerIsolateData::ensureInitialized(m_isolate);
    m_world = DOMWrapperWorld::create(WorkerWorldId);
    m_interruptor = adoptPtr(new V8IsolateInterruptor(m_isolate));
    ThreadState::current()->addInterruptor(m_interruptor.get());
}

// We need to postpone V8 Isolate destruction until the very end of
// worker thread finalization when all objects on the worker heap
// are destroyed.
class IsolateCleanupTask : public ThreadState::CleanupTask {
public:
    static PassOwnPtr<IsolateCleanupTask> create(v8::Isolate* isolate)
    {
        return adoptPtr(new IsolateCleanupTask(isolate));
    }

    virtual void postCleanup()
    {
        V8PerIsolateData::dispose(m_isolate);
        m_isolate->Exit();
        m_isolate->Dispose();
    }

private:
    explicit IsolateCleanupTask(v8::Isolate* isolate) : m_isolate(isolate)  { }

    v8::Isolate* m_isolate;
};

WorkerScriptController::~WorkerScriptController()
{
    ThreadState::current()->removeInterruptor(m_interruptor.get());

    m_world->dispose();

    // The corresponding call to didStartWorkerRunLoop is in
    // WorkerThread::initialize().
    // See http://webkit.org/b/83104#c14 for why this is here.
    blink::Platform::current()->didStopWorkerRunLoop(blink::WebWorkerRunLoop(m_workerGlobalScope.thread()));

    if (isContextInitialized())
        m_scriptState->disposePerContextData();

    ThreadState::current()->addCleanupTask(IsolateCleanupTask::create(m_isolate));
}

bool WorkerScriptController::initializeContextIfNeeded()
{
    v8::HandleScope handleScope(m_isolate);

    if (isContextInitialized())
        return true;

    v8::Handle<v8::Context> context = v8::Context::New(m_isolate);
    if (context.IsEmpty())
        return false;

    m_scriptState = ScriptState::create(context, m_world);

    ScriptState::Scope scope(m_scriptState.get());

    // Set DebugId for the new context.
    context->SetEmbedderData(0, v8AtomicString(m_isolate, "worker"));

    // Create a new JS object and use it as the prototype for the shadow global object.
    const WrapperTypeInfo* contextType = &V8DedicatedWorkerGlobalScope::wrapperTypeInfo;
    if (m_workerGlobalScope.isServiceWorkerGlobalScope())
        contextType = &V8ServiceWorkerGlobalScope::wrapperTypeInfo;
    else if (!m_workerGlobalScope.isDedicatedWorkerGlobalScope())
        contextType = &V8SharedWorkerGlobalScope::wrapperTypeInfo;
    v8::Handle<v8::Function> workerGlobalScopeConstructor = m_scriptState->perContextData()->constructorForType(contextType);
    v8::Local<v8::Object> jsWorkerGlobalScope = V8ObjectConstructor::newInstance(m_isolate, workerGlobalScopeConstructor);
    if (jsWorkerGlobalScope.IsEmpty()) {
        m_scriptState->disposePerContextData();
        return false;
    }

    V8DOMWrapper::associateObjectWithWrapper<V8WorkerGlobalScope>(PassRefPtrWillBeRawPtr<WorkerGlobalScope>(&m_workerGlobalScope), contextType, jsWorkerGlobalScope, m_isolate, WrapperConfiguration::Dependent);

    // Insert the object instance as the prototype of the shadow object.
    v8::Handle<v8::Object> globalObject = v8::Handle<v8::Object>::Cast(m_scriptState->context()->Global()->GetPrototype());
    globalObject->SetPrototype(jsWorkerGlobalScope);

    return true;
}

ScriptValue WorkerScriptController::evaluate(const String& script, const String& fileName, const TextPosition& scriptStartPosition)
{
    if (!initializeContextIfNeeded())
        return ScriptValue();

    ScriptState::Scope scope(m_scriptState.get());

    if (!m_disableEvalPending.isEmpty()) {
        m_scriptState->context()->AllowCodeGenerationFromStrings(false);
        m_scriptState->context()->SetErrorMessageForCodeGenerationFromStrings(v8String(m_isolate, m_disableEvalPending));
        m_disableEvalPending = String();
    }

    v8::TryCatch block;

    v8::Handle<v8::String> scriptString = v8String(m_isolate, script);
    v8::Handle<v8::Script> compiledScript = V8ScriptRunner::compileScript(scriptString, fileName, scriptStartPosition, 0, m_isolate);
    v8::Local<v8::Value> result = V8ScriptRunner::runCompiledScript(compiledScript, &m_workerGlobalScope, m_isolate);

    if (!block.CanContinue()) {
        m_workerGlobalScope.script()->forbidExecution();
        return ScriptValue();
    }

    if (block.HasCaught()) {
        v8::Local<v8::Message> message = block.Message();
        m_globalScopeExecutionState->hadException = true;
        m_globalScopeExecutionState->errorMessage = toCoreString(message->Get());
        m_globalScopeExecutionState->lineNumber = message->GetLineNumber();
        m_globalScopeExecutionState->columnNumber = message->GetStartColumn() + 1;
        TOSTRING_DEFAULT(V8StringResource<>, sourceURL, message->GetScriptOrigin().ResourceName(), ScriptValue());
        m_globalScopeExecutionState->sourceURL = sourceURL;
        m_globalScopeExecutionState->exception = ScriptValue(m_scriptState.get(), block.Exception());
        block.Reset();
    } else {
        m_globalScopeExecutionState->hadException = false;
    }

    if (result.IsEmpty() || result->IsUndefined())
        return ScriptValue();

    return ScriptValue(m_scriptState.get(), result);
}

void WorkerScriptController::evaluate(const ScriptSourceCode& sourceCode, RefPtrWillBeRawPtr<ErrorEvent>* errorEvent)
{
    if (isExecutionForbidden())
        return;

    WorkerGlobalScopeExecutionState state(this);
    evaluate(sourceCode.source(), sourceCode.url().string(), sourceCode.startPosition());
    if (state.hadException) {
        if (errorEvent) {
            if (state.m_errorEventFromImportedScript) {
                // Propagate inner error event outwards.
                *errorEvent = state.m_errorEventFromImportedScript.release();
                return;
            }
            if (m_workerGlobalScope.shouldSanitizeScriptError(state.sourceURL, NotSharableCrossOrigin))
                *errorEvent = ErrorEvent::createSanitizedError(m_world.get());
            else
                *errorEvent = ErrorEvent::create(state.errorMessage, state.sourceURL, state.lineNumber, state.columnNumber, m_world.get());
            V8ErrorHandler::storeExceptionOnErrorEventWrapper(errorEvent->get(), state.exception.v8Value(), m_scriptState->context()->Global(), m_isolate);
        } else {
            ASSERT(!m_workerGlobalScope.shouldSanitizeScriptError(state.sourceURL, NotSharableCrossOrigin));
            RefPtrWillBeRawPtr<ErrorEvent> event = nullptr;
            if (state.m_errorEventFromImportedScript)
                event = state.m_errorEventFromImportedScript.release();
            else
                event = ErrorEvent::create(state.errorMessage, state.sourceURL, state.lineNumber, state.columnNumber, m_world.get());
            m_workerGlobalScope.reportException(event, nullptr, NotSharableCrossOrigin);
        }
    }
}

void WorkerScriptController::scheduleExecutionTermination()
{
    // The mutex provides a memory barrier to ensure that once
    // termination is scheduled, isExecutionTerminating will
    // accurately reflect that state when called from another thread.
    {
        MutexLocker locker(m_scheduledTerminationMutex);
        m_executionScheduledToTerminate = true;
    }
    v8::V8::TerminateExecution(m_isolate);
}

bool WorkerScriptController::isExecutionTerminating() const
{
    // See comments in scheduleExecutionTermination regarding mutex usage.
    MutexLocker locker(m_scheduledTerminationMutex);
    return m_executionScheduledToTerminate;
}

void WorkerScriptController::forbidExecution()
{
    ASSERT(m_workerGlobalScope.isContextThread());
    m_executionForbidden = true;
}

bool WorkerScriptController::isExecutionForbidden() const
{
    ASSERT(m_workerGlobalScope.isContextThread());
    return m_executionForbidden;
}

void WorkerScriptController::disableEval(const String& errorMessage)
{
    m_disableEvalPending = errorMessage;
}

void WorkerScriptController::rethrowExceptionFromImportedScript(PassRefPtrWillBeRawPtr<ErrorEvent> errorEvent, ExceptionState& exceptionState)
{
    const String& errorMessage = errorEvent->message();
    if (m_globalScopeExecutionState)
        m_globalScopeExecutionState->m_errorEventFromImportedScript = errorEvent;
    exceptionState.rethrowV8Exception(V8ThrowException::createGeneralError(errorMessage, m_isolate));
}

} // namespace blink
