qtdeclarative/src/qml/jsruntime/qv4engine.cpp

/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the QtQml module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
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** accordance with the commercial license agreement provided with the
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** information use the contact form at https://www.qt.io/contact-us.
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** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 3 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL3 included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 3 requirements
** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
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** Alternatively, this file may be used under the terms of the GNU
** General Public License version 2.0 or (at your option) the GNU General
** Public license version 3 or any later version approved by the KDE Free
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** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
** included in the packaging of this file. Please review the following
** information to ensure the GNU General Public License requirements will
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****************************************************************************/
#include <qv4engine_p.h>
#include <qv4qmlcontext_p.h>
#include <qv4value_p.h>
#include <qv4object_p.h>
#include <qv4objectproto_p.h>
#include <qv4objectiterator_p.h>
#include <qv4arrayobject_p.h>
#include <qv4booleanobject_p.h>
#include <qv4globalobject_p.h>
#include <qv4errorobject_p.h>
#include <qv4functionobject_p.h>
#include "qv4function_p.h"
#include <qv4mathobject_p.h>
#include <qv4numberobject_p.h>
#include <qv4regexpobject_p.h>
#include <qv4regexp_p.h>
#include <qv4variantobject_p.h>
#include <qv4runtime_p.h>
#include <private/qv4mm_p.h>
#include <qv4argumentsobject_p.h>
#include <qv4dateobject_p.h>
#include <qv4jsonobject_p.h>
#include <qv4stringobject_p.h>
#include <qv4identifiertable_p.h>
#include "qv4debugging_p.h"
#include "qv4profiling_p.h"
#include "qv4executableallocator_p.h"
#include "qv4sequenceobject_p.h"
#include "qv4qobjectwrapper_p.h"
#include "qv4memberdata_p.h"
#include "qv4arraybuffer_p.h"
#include "qv4dataview_p.h"
#include "qv4typedarray_p.h"
#include <private/qv8engine_p.h>
#include <private/qjsvalue_p.h>
#include <private/qqmltypewrapper_p.h>
#include <private/qqmlvaluetypewrapper_p.h>
#include <private/qqmlvaluetype_p.h>
#include <private/qqmllistwrapper_p.h>
#include <private/qqmllist_p.h>
#include <private/qqmllocale_p.h>

#include <QtCore/QTextStream>
#include <QDateTime>

#ifdef V4_ENABLE_JIT
#include "qv4isel_masm_p.h"
#endif // V4_ENABLE_JIT

#if QT_CONFIG(qml_interpreter)
#include "qv4isel_moth_p.h"
#endif

#if USE(PTHREADS)
#  include <pthread.h>
#  include <sys/resource.h>
#if HAVE(PTHREAD_NP_H)
#  include <pthread_np.h>
#endif
#endif

#ifdef V4_USE_VALGRIND
#include <valgrind/memcheck.h>
#endif

QT_BEGIN_NAMESPACE

using namespace QV4;

static QBasicAtomicInt engineSerial = Q_BASIC_ATOMIC_INITIALIZER(1);

static ReturnedValue throwTypeError(CallContext *ctx)
{
    return ctx->engine()->throwTypeError();
}


#ifdef V4_BOOTSTRAP
QJSEngine *ExecutionEngine::jsEngine() const
{
    return v8Engine->publicEngine();
}

QQmlEngine *ExecutionEngine::qmlEngine() const
{
    return v8Engine->engine();
}
#endif // V4_BOOTSTRAP

qint32 ExecutionEngine::maxCallDepth = -1;

ExecutionEngine::ExecutionEngine(EvalISelFactory *factory)
    : current(0)
    , hasException(false)
    , callDepth(0)
    , memoryManager(new QV4::MemoryManager(this))
    , executableAllocator(new QV4::ExecutableAllocator)
    , regExpAllocator(new QV4::ExecutableAllocator)
    , currentContext(0)
    , bumperPointerAllocator(new WTF::BumpPointerAllocator)
    , jsStack(new WTF::PageAllocation)
    , globalCode(0)
    , v8Engine(0)
    , argumentsAccessors(0)
    , nArgumentsAccessors(0)
    , m_engineId(engineSerial.fetchAndAddOrdered(1))
    , regExpCache(0)
    , m_multiplyWrappedQObjects(0)
#ifndef QT_NO_QML_DEBUGGER
    , m_debugger(0)
    , m_profiler(0)
#endif
{
    if (maxCallDepth == -1) {
        bool ok = false;
        maxCallDepth = qEnvironmentVariableIntValue("QV4_MAX_CALL_DEPTH", &ok);
        if (!ok || maxCallDepth <= 0) {
            maxCallDepth = 1234;
        }
    }
    Q_ASSERT(maxCallDepth > 0);

    MemoryManager::GCBlocker gcBlocker(memoryManager);

    if (!factory) {
#if QT_CONFIG(qml_interpreter)
        bool jitDisabled = true;

#ifdef V4_ENABLE_JIT
        static const bool forceMoth = !qEnvironmentVariableIsEmpty("QV4_FORCE_INTERPRETER") ||
                                      !OSAllocator::canAllocateExecutableMemory();
        if (forceMoth) {
            factory = new Moth::ISelFactory;
        } else {
            factory = new JIT::ISelFactory;
            jitDisabled = false;
        }
#else // !V4_ENABLE_JIT
        factory = new Moth::ISelFactory;
#endif // V4_ENABLE_JIT

        if (jitDisabled) {
            qWarning("JIT is disabled for QML. Property bindings and animations will be "
                     "very slow. Visit https://wiki.qt.io/V4 to learn about possible "
                     "solutions for your platform.");
        }
#else
        factory = new JIT::ISelFactory;
#endif
    }
    iselFactory.reset(factory);

    // reserve space for the JS stack
    // we allow it to grow to 2 times JSStackLimit, as we can overshoot due to garbage collection
    // and ScopedValues allocated outside of JIT'ed methods.
    *jsStack = WTF::PageAllocation::allocate(2 * JSStackLimit, WTF::OSAllocator::JSVMStackPages,
                                             /* writable */ true, /* executable */ false,
                                             /* includesGuardPages */ true);
    jsStackBase = (Value *)jsStack->base();
#ifdef V4_USE_VALGRIND
    VALGRIND_MAKE_MEM_UNDEFINED(jsStackBase, 2*JSStackLimit);
#endif

    jsStackTop = jsStackBase;

    exceptionValue = jsAlloca(1);
    globalObject = static_cast<Object *>(jsAlloca(1));
    jsObjects = jsAlloca(NJSObjects);
    typedArrayPrototype = static_cast<Object *>(jsAlloca(NTypedArrayTypes));
    typedArrayCtors = static_cast<FunctionObject *>(jsAlloca(NTypedArrayTypes));
    jsStrings = jsAlloca(NJSStrings);

    // set up stack limits
    jsStackLimit = jsStackBase + JSStackLimit/sizeof(Value);

    identifierTable = new IdentifierTable(this);

    classPool = new InternalClassPool;

    emptyClass =  new (classPool) InternalClass(this);

    jsStrings[String_Empty] = newIdentifier(QString());
    jsStrings[String_undefined] = newIdentifier(QStringLiteral("undefined"));
    jsStrings[String_null] = newIdentifier(QStringLiteral("null"));
    jsStrings[String_true] = newIdentifier(QStringLiteral("true"));
    jsStrings[String_false] = newIdentifier(QStringLiteral("false"));
    jsStrings[String_boolean] = newIdentifier(QStringLiteral("boolean"));
    jsStrings[String_number] = newIdentifier(QStringLiteral("number"));
    jsStrings[String_string] = newIdentifier(QStringLiteral("string"));
    jsStrings[String_object] = newIdentifier(QStringLiteral("object"));
    jsStrings[String_function] = newIdentifier(QStringLiteral("function"));
    jsStrings[String_length] = newIdentifier(QStringLiteral("length"));
    jsStrings[String_prototype] = newIdentifier(QStringLiteral("prototype"));
    jsStrings[String_constructor] = newIdentifier(QStringLiteral("constructor"));
    jsStrings[String_arguments] = newIdentifier(QStringLiteral("arguments"));
    jsStrings[String_caller] = newIdentifier(QStringLiteral("caller"));
    jsStrings[String_callee] = newIdentifier(QStringLiteral("callee"));
    jsStrings[String_this] = newIdentifier(QStringLiteral("this"));
    jsStrings[String___proto__] = newIdentifier(QStringLiteral("__proto__"));
    jsStrings[String_enumerable] = newIdentifier(QStringLiteral("enumerable"));
    jsStrings[String_configurable] = newIdentifier(QStringLiteral("configurable"));
    jsStrings[String_writable] = newIdentifier(QStringLiteral("writable"));
    jsStrings[String_value] = newIdentifier(QStringLiteral("value"));
    jsStrings[String_get] = newIdentifier(QStringLiteral("get"));
    jsStrings[String_set] = newIdentifier(QStringLiteral("set"));
    jsStrings[String_eval] = newIdentifier(QStringLiteral("eval"));
    jsStrings[String_uintMax] = newIdentifier(QStringLiteral("4294967295"));
    jsStrings[String_name] = newIdentifier(QStringLiteral("name"));
    jsStrings[String_index] = newIdentifier(QStringLiteral("index"));
    jsStrings[String_input] = newIdentifier(QStringLiteral("input"));
    jsStrings[String_toString] = newIdentifier(QStringLiteral("toString"));
    jsStrings[String_destroy] = newIdentifier(QStringLiteral("destroy"));
    jsStrings[String_valueOf] = newIdentifier(QStringLiteral("valueOf"));
    jsStrings[String_byteLength] = newIdentifier(QStringLiteral("byteLength"));
    jsStrings[String_byteOffset] = newIdentifier(QStringLiteral("byteOffset"));
    jsStrings[String_buffer] = newIdentifier(QStringLiteral("buffer"));
    jsStrings[String_lastIndex] = newIdentifier(QStringLiteral("lastIndex"));

    jsObjects[ObjectProto] = memoryManager->allocObject<ObjectPrototype>(emptyClass);

    arrayClass = emptyClass->addMember(id_length(), Attr_NotConfigurable|Attr_NotEnumerable);
    jsObjects[ArrayProto] = memoryManager->allocObject<ArrayPrototype>(arrayClass, objectPrototype());

    InternalClass *argsClass = emptyClass->addMember(id_length(), Attr_NotEnumerable);
    argumentsObjectClass = argsClass->addMember(id_callee(), Attr_Data|Attr_NotEnumerable);
    strictArgumentsObjectClass = argsClass->addMember(id_callee(), Attr_Accessor|Attr_NotConfigurable|Attr_NotEnumerable);
    strictArgumentsObjectClass = strictArgumentsObjectClass->addMember(id_caller(), Attr_Accessor|Attr_NotConfigurable|Attr_NotEnumerable);

    *static_cast<Value *>(globalObject) = newObject();
    Q_ASSERT(globalObject->d()->vtable());
    initRootContext();

    stringClass = emptyClass->addMember(id_length(), Attr_ReadOnly);
    Q_ASSERT(stringClass->find(id_length()) == Heap::StringObject::LengthPropertyIndex);
    jsObjects[StringProto] = memoryManager->allocObject<StringPrototype>(stringClass, objectPrototype());
    jsObjects[NumberProto] = memoryManager->allocObject<NumberPrototype>(emptyClass, objectPrototype());
    jsObjects[BooleanProto] = memoryManager->allocObject<BooleanPrototype>(emptyClass, objectPrototype());
    jsObjects[DateProto] = memoryManager->allocObject<DatePrototype>(emptyClass, objectPrototype());

    uint index;
    InternalClass *functionProtoClass = emptyClass->addMember(id_prototype(), Attr_NotEnumerable, &index);
    Q_ASSERT(index == Heap::FunctionObject::Index_Prototype);
    jsObjects[FunctionProto] = memoryManager->allocObject<FunctionPrototype>(functionProtoClass, objectPrototype());
    functionClass = emptyClass->addMember(id_prototype(), Attr_NotEnumerable|Attr_NotConfigurable, &index);
    Q_ASSERT(index == Heap::FunctionObject::Index_Prototype);
    simpleScriptFunctionClass = functionClass->addMember(id_name(), Attr_ReadOnly, &index);
    Q_ASSERT(index == Heap::SimpleScriptFunction::Index_Name);
    simpleScriptFunctionClass = simpleScriptFunctionClass->addMember(id_length(), Attr_ReadOnly, &index);
    Q_ASSERT(index == Heap::SimpleScriptFunction::Index_Length);
    protoClass = emptyClass->addMember(id_constructor(), Attr_NotEnumerable, &index);
    Q_ASSERT(index == Heap::FunctionObject::Index_ProtoConstructor);

    Scope scope(this);
    ScopedString str(scope);
    regExpObjectClass = emptyClass->addMember(id_lastIndex(), Attr_NotEnumerable|Attr_NotConfigurable, &index);
    Q_ASSERT(index == RegExpObject::Index_LastIndex);
    regExpObjectClass = regExpObjectClass->addMember((str = newIdentifier(QStringLiteral("source"))), Attr_ReadOnly, &index);
    Q_ASSERT(index == RegExpObject::Index_Source);
    regExpObjectClass = regExpObjectClass->addMember((str = newIdentifier(QStringLiteral("global"))), Attr_ReadOnly, &index);
    Q_ASSERT(index == RegExpObject::Index_Global);
    regExpObjectClass = regExpObjectClass->addMember((str = newIdentifier(QStringLiteral("ignoreCase"))), Attr_ReadOnly, &index);
    Q_ASSERT(index == RegExpObject::Index_IgnoreCase);
    regExpObjectClass = regExpObjectClass->addMember((str = newIdentifier(QStringLiteral("multiline"))), Attr_ReadOnly, &index);
    Q_ASSERT(index == RegExpObject::Index_Multiline);

    jsObjects[RegExpProto] = memoryManager->allocObject<RegExpPrototype>(regExpObjectClass, objectPrototype());
    regExpExecArrayClass = arrayClass->addMember(id_index(), Attr_Data, &index);
    Q_ASSERT(index == RegExpObject::Index_ArrayIndex);
    regExpExecArrayClass = regExpExecArrayClass->addMember(id_input(), Attr_Data, &index);
    Q_ASSERT(index == RegExpObject::Index_ArrayInput);

    errorClass = emptyClass->addMember((str = newIdentifier(QStringLiteral("stack"))), Attr_Accessor|Attr_NotConfigurable|Attr_NotEnumerable, &index);
    Q_ASSERT(index == ErrorObject::Index_Stack);
    errorClass = errorClass->addMember((str = newIdentifier(QStringLiteral("fileName"))), Attr_Data|Attr_NotEnumerable, &index);
    Q_ASSERT(index == ErrorObject::Index_FileName);
    errorClass = errorClass->addMember((str = newIdentifier(QStringLiteral("lineNumber"))), Attr_Data|Attr_NotEnumerable, &index);
    Q_ASSERT(index == ErrorObject::Index_LineNumber);
    errorClassWithMessage = errorClass->addMember((str = newIdentifier(QStringLiteral("message"))), Attr_Data|Attr_NotEnumerable, &index);
    Q_ASSERT(index == ErrorObject::Index_Message);
    errorProtoClass = emptyClass->addMember(id_constructor(), Attr_Data|Attr_NotEnumerable, &index);
    Q_ASSERT(index == ErrorPrototype::Index_Constructor);
    errorProtoClass = errorProtoClass->addMember((str = newIdentifier(QStringLiteral("message"))), Attr_Data|Attr_NotEnumerable, &index);
    Q_ASSERT(index == ErrorPrototype::Index_Message);
    errorProtoClass = errorProtoClass->addMember(id_name(), Attr_Data|Attr_NotEnumerable, &index);
    Q_ASSERT(index == ErrorPrototype::Index_Name);

    jsObjects[GetStack_Function] = BuiltinFunction::create(rootContext(), str = newIdentifier(QStringLiteral("stack")), ErrorObject::method_get_stack);
    getStackFunction()->defineReadonlyProperty(id_length(), Primitive::fromInt32(0));

    jsObjects[ErrorProto] = memoryManager->allocObject<ErrorPrototype>(errorProtoClass, objectPrototype());
    jsObjects[EvalErrorProto] = memoryManager->allocObject<EvalErrorPrototype>(errorProtoClass, errorPrototype());
    jsObjects[RangeErrorProto] = memoryManager->allocObject<RangeErrorPrototype>(errorProtoClass, errorPrototype());
    jsObjects[ReferenceErrorProto] = memoryManager->allocObject<ReferenceErrorPrototype>(errorProtoClass, errorPrototype());
    jsObjects[SyntaxErrorProto] = memoryManager->allocObject<SyntaxErrorPrototype>(errorProtoClass, errorPrototype());
    jsObjects[TypeErrorProto] = memoryManager->allocObject<TypeErrorPrototype>(errorProtoClass, errorPrototype());
    jsObjects[URIErrorProto] = memoryManager->allocObject<URIErrorPrototype>(errorProtoClass, errorPrototype());

    jsObjects[VariantProto] = memoryManager->allocObject<VariantPrototype>(emptyClass, objectPrototype());
    Q_ASSERT(variantPrototype()->prototype() == objectPrototype()->d());

    jsObjects[SequenceProto] = ScopedValue(scope, memoryManager->allocObject<SequencePrototype>(arrayClass, arrayPrototype()));

    ExecutionContext *global = rootContext();
    jsObjects[Object_Ctor] = memoryManager->allocObject<ObjectCtor>(global);
    jsObjects[String_Ctor] = memoryManager->allocObject<StringCtor>(global);
    jsObjects[Number_Ctor] = memoryManager->allocObject<NumberCtor>(global);
    jsObjects[Boolean_Ctor] = memoryManager->allocObject<BooleanCtor>(global);
    jsObjects[Array_Ctor] = memoryManager->allocObject<ArrayCtor>(global);
    jsObjects[Function_Ctor] = memoryManager->allocObject<FunctionCtor>(global);
    jsObjects[Date_Ctor] = memoryManager->allocObject<DateCtor>(global);
    jsObjects[RegExp_Ctor] = memoryManager->allocObject<RegExpCtor>(global);
    jsObjects[Error_Ctor] = memoryManager->allocObject<ErrorCtor>(global);
    jsObjects[EvalError_Ctor] = memoryManager->allocObject<EvalErrorCtor>(global);
    jsObjects[RangeError_Ctor] = memoryManager->allocObject<RangeErrorCtor>(global);
    jsObjects[ReferenceError_Ctor] = memoryManager->allocObject<ReferenceErrorCtor>(global);
    jsObjects[SyntaxError_Ctor] = memoryManager->allocObject<SyntaxErrorCtor>(global);
    jsObjects[TypeError_Ctor] = memoryManager->allocObject<TypeErrorCtor>(global);
    jsObjects[URIError_Ctor] = memoryManager->allocObject<URIErrorCtor>(global);

    static_cast<ObjectPrototype *>(objectPrototype())->init(this, objectCtor());
    static_cast<StringPrototype *>(stringPrototype())->init(this, stringCtor());
    static_cast<NumberPrototype *>(numberPrototype())->init(this, numberCtor());
    static_cast<BooleanPrototype *>(booleanPrototype())->init(this, booleanCtor());
    static_cast<ArrayPrototype *>(arrayPrototype())->init(this, arrayCtor());
    static_cast<DatePrototype *>(datePrototype())->init(this, dateCtor());
    static_cast<FunctionPrototype *>(functionPrototype())->init(this, functionCtor());
    static_cast<RegExpPrototype *>(regExpPrototype())->init(this, regExpCtor());
    static_cast<ErrorPrototype *>(errorPrototype())->init(this, errorCtor());
    static_cast<EvalErrorPrototype *>(evalErrorPrototype())->init(this, evalErrorCtor());
    static_cast<RangeErrorPrototype *>(rangeErrorPrototype())->init(this, rangeErrorCtor());
    static_cast<ReferenceErrorPrototype *>(referenceErrorPrototype())->init(this, referenceErrorCtor());
    static_cast<SyntaxErrorPrototype *>(syntaxErrorPrototype())->init(this, syntaxErrorCtor());
    static_cast<TypeErrorPrototype *>(typeErrorPrototype())->init(this, typeErrorCtor());
    static_cast<URIErrorPrototype *>(uRIErrorPrototype())->init(this, uRIErrorCtor());

    static_cast<VariantPrototype *>(variantPrototype())->init();
    sequencePrototype()->cast<SequencePrototype>()->init();


    // typed arrays

    jsObjects[ArrayBuffer_Ctor] = memoryManager->allocObject<ArrayBufferCtor>(global);
    jsObjects[ArrayBufferProto] = memoryManager->allocObject<ArrayBufferPrototype>();
    static_cast<ArrayBufferPrototype *>(arrayBufferPrototype())->init(this, arrayBufferCtor());

    jsObjects[DataView_Ctor] = memoryManager->allocObject<DataViewCtor>(global);
    jsObjects[DataViewProto] = memoryManager->allocObject<DataViewPrototype>();
    static_cast<DataViewPrototype *>(dataViewPrototype())->init(this, dataViewCtor());
    jsObjects[ValueTypeProto] = (Heap::Base *) 0;
    jsObjects[SignalHandlerProto] = (Heap::Base *) 0;

    for (int i = 0; i < Heap::TypedArray::NTypes; ++i) {
        static_cast<Value &>(typedArrayCtors[i]) = memoryManager->allocObject<TypedArrayCtor>(global, Heap::TypedArray::Type(i));
        static_cast<Value &>(typedArrayPrototype[i]) = memoryManager->allocObject<TypedArrayPrototype>(Heap::TypedArray::Type(i));
        typedArrayPrototype[i].as<TypedArrayPrototype>()->init(this, static_cast<TypedArrayCtor *>(typedArrayCtors[i].as<Object>()));
    }

    //
    // set up the global object
    //
    rootContext()->d()->global = globalObject->d();
    rootContext()->d()->callData->thisObject = globalObject;
    Q_ASSERT(globalObject->d()->vtable());

    globalObject->defineDefaultProperty(QStringLiteral("Object"), *objectCtor());
    globalObject->defineDefaultProperty(QStringLiteral("String"), *stringCtor());
    globalObject->defineDefaultProperty(QStringLiteral("Number"), *numberCtor());
    globalObject->defineDefaultProperty(QStringLiteral("Boolean"), *booleanCtor());
    globalObject->defineDefaultProperty(QStringLiteral("Array"), *arrayCtor());
    globalObject->defineDefaultProperty(QStringLiteral("Function"), *functionCtor());
    globalObject->defineDefaultProperty(QStringLiteral("Date"), *dateCtor());
    globalObject->defineDefaultProperty(QStringLiteral("RegExp"), *regExpCtor());
    globalObject->defineDefaultProperty(QStringLiteral("Error"), *errorCtor());
    globalObject->defineDefaultProperty(QStringLiteral("EvalError"), *evalErrorCtor());
    globalObject->defineDefaultProperty(QStringLiteral("RangeError"), *rangeErrorCtor());
    globalObject->defineDefaultProperty(QStringLiteral("ReferenceError"), *referenceErrorCtor());
    globalObject->defineDefaultProperty(QStringLiteral("SyntaxError"), *syntaxErrorCtor());
    globalObject->defineDefaultProperty(QStringLiteral("TypeError"), *typeErrorCtor());
    globalObject->defineDefaultProperty(QStringLiteral("URIError"), *uRIErrorCtor());

    globalObject->defineDefaultProperty(QStringLiteral("ArrayBuffer"), *arrayBufferCtor());
    globalObject->defineDefaultProperty(QStringLiteral("DataView"), *dataViewCtor());
    for (int i = 0; i < Heap::TypedArray::NTypes; ++i)
        globalObject->defineDefaultProperty((str = typedArrayCtors[i].as<FunctionObject>()->name())->toQString(), typedArrayCtors[i]);
    ScopedObject o(scope);
    globalObject->defineDefaultProperty(QStringLiteral("Math"), (o = memoryManager->allocObject<MathObject>()));
    globalObject->defineDefaultProperty(QStringLiteral("JSON"), (o = memoryManager->allocObject<JsonObject>()));

    globalObject->defineReadonlyProperty(QStringLiteral("undefined"), Primitive::undefinedValue());
    globalObject->defineReadonlyProperty(QStringLiteral("NaN"), Primitive::fromDouble(std::numeric_limits<double>::quiet_NaN()));
    globalObject->defineReadonlyProperty(QStringLiteral("Infinity"), Primitive::fromDouble(Q_INFINITY));


    jsObjects[Eval_Function] = memoryManager->allocObject<EvalFunction>(global);
    globalObject->defineDefaultProperty(QStringLiteral("eval"), *evalFunction());

    globalObject->defineDefaultProperty(QStringLiteral("parseInt"), GlobalFunctions::method_parseInt, 2);
    globalObject->defineDefaultProperty(QStringLiteral("parseFloat"), GlobalFunctions::method_parseFloat, 1);
    globalObject->defineDefaultProperty(QStringLiteral("isNaN"), GlobalFunctions::method_isNaN, 1);
    globalObject->defineDefaultProperty(QStringLiteral("isFinite"), GlobalFunctions::method_isFinite, 1);
    globalObject->defineDefaultProperty(QStringLiteral("decodeURI"), GlobalFunctions::method_decodeURI, 1);
    globalObject->defineDefaultProperty(QStringLiteral("decodeURIComponent"), GlobalFunctions::method_decodeURIComponent, 1);
    globalObject->defineDefaultProperty(QStringLiteral("encodeURI"), GlobalFunctions::method_encodeURI, 1);
    globalObject->defineDefaultProperty(QStringLiteral("encodeURIComponent"), GlobalFunctions::method_encodeURIComponent, 1);
    globalObject->defineDefaultProperty(QStringLiteral("escape"), GlobalFunctions::method_escape, 1);
    globalObject->defineDefaultProperty(QStringLiteral("unescape"), GlobalFunctions::method_unescape, 1);

    ScopedString name(scope, newString(QStringLiteral("thrower")));
    jsObjects[ThrowerObject] = BuiltinFunction::create(global, name, ::throwTypeError);
}

ExecutionEngine::~ExecutionEngine()
{
#ifndef QT_NO_QML_DEBUGGER
    delete m_debugger;
    m_debugger = 0;
    delete m_profiler;
    m_profiler = 0;
#endif
    delete m_multiplyWrappedQObjects;
    m_multiplyWrappedQObjects = 0;
    delete identifierTable;
    delete memoryManager;

    QSet<QV4::CompiledData::CompilationUnit*> remainingUnits;
    qSwap(compilationUnits, remainingUnits);
    foreach (QV4::CompiledData::CompilationUnit *unit, remainingUnits)
        unit->unlink();

    emptyClass->destroy();
    delete classPool;
    delete bumperPointerAllocator;
    delete regExpCache;
    delete regExpAllocator;
    delete executableAllocator;
    jsStack->deallocate();
    delete jsStack;
    delete [] argumentsAccessors;
}

#ifndef QT_NO_QML_DEBUGGER
void ExecutionEngine::setDebugger(Debugging::Debugger *debugger)
{
    Q_ASSERT(!m_debugger);
    m_debugger = debugger;
}

void ExecutionEngine::setProfiler(Profiling::Profiler *profiler)
{
    Q_ASSERT(!m_profiler);
    m_profiler = profiler;
}
#endif // QT_NO_QML_DEBUGGER

void ExecutionEngine::initRootContext()
{
    Scope scope(this);
    Scoped<GlobalContext> r(scope, memoryManager->allocManaged<GlobalContext>(
                                sizeof(GlobalContext::Data) + sizeof(CallData)));
    r->d_unchecked()->init(this);
    r->d()->callData = reinterpret_cast<CallData *>(r->d() + 1);
    r->d()->callData->tag = QV4::Value::Integer_Type_Internal;
    r->d()->callData->argc = 0;
    r->d()->callData->thisObject = globalObject;
    r->d()->callData->args[0] = Encode::undefined();
    jsObjects[RootContext] = r;
    jsObjects[IntegerNull] = Encode((int)0);

    currentContext = static_cast<ExecutionContext *>(jsObjects + RootContext);
    current = currentContext->d();
}

InternalClass *ExecutionEngine::newClass(const InternalClass &other)
{
    return new (classPool) InternalClass(other);
}

ExecutionContext *ExecutionEngine::pushGlobalContext()
{
    pushContext(rootContext()->d());

    Q_ASSERT(current == rootContext()->d());
    return currentContext;
}

Heap::Object *ExecutionEngine::newObject()
{
    return memoryManager->allocObject<Object>();
}

Heap::Object *ExecutionEngine::newObject(InternalClass *internalClass, QV4::Object *prototype)
{
    return memoryManager->allocObject<Object>(internalClass, prototype);
}

Heap::String *ExecutionEngine::newString(const QString &s)
{
    Scope scope(this);
    return ScopedString(scope, memoryManager->allocWithStringData<String>(s.length() * sizeof(QChar), s))->d();
}

Heap::String *ExecutionEngine::newIdentifier(const QString &text)
{
    return identifierTable->insertString(text);
}

Heap::Object *ExecutionEngine::newStringObject(const String *string)
{
    return memoryManager->allocObject<StringObject>(string);
}

Heap::Object *ExecutionEngine::newNumberObject(double value)
{
    return memoryManager->allocObject<NumberObject>(value);
}

Heap::Object *ExecutionEngine::newBooleanObject(bool b)
{
    return memoryManager->allocObject<BooleanObject>(b);
}

Heap::ArrayObject *ExecutionEngine::newArrayObject(int count)
{
    Scope scope(this);
    ScopedArrayObject object(scope, memoryManager->allocObject<ArrayObject>());

    if (count) {
        if (count < 0x1000)
            object->arrayReserve(count);
        object->setArrayLengthUnchecked(count);
    }
    return object->d();
}

Heap::ArrayObject *ExecutionEngine::newArrayObject(const Value *values, int length)
{
    Scope scope(this);
    ScopedArrayObject a(scope, memoryManager->allocObject<ArrayObject>());

    if (length) {
        size_t size = sizeof(Heap::ArrayData) + (length-1)*sizeof(Value);
        Heap::SimpleArrayData *d = scope.engine->memoryManager->allocManaged<SimpleArrayData>(size);
        d->init();
        d->alloc = length;
        d->type = Heap::ArrayData::Simple;
        d->offset = 0;
        d->len = length;
        memcpy(&d->arrayData, values, length*sizeof(Value));
        a->d()->arrayData = d;
        a->setArrayLengthUnchecked(length);
    }
    return a->d();
}

Heap::ArrayObject *ExecutionEngine::newArrayObject(const QStringList &list)
{
    Scope scope(this);
    ScopedArrayObject object(scope, memoryManager->allocObject<ArrayObject>(list));
    return object->d();
}

Heap::ArrayObject *ExecutionEngine::newArrayObject(InternalClass *internalClass, Object *prototype)
{
    Scope scope(this);
    ScopedArrayObject object(scope, memoryManager->allocObject<ArrayObject>(internalClass, prototype));
    return object->d();
}

Heap::ArrayBuffer *ExecutionEngine::newArrayBuffer(const QByteArray &array)
{
    return memoryManager->allocObject<ArrayBuffer>(array);
}

Heap::ArrayBuffer *ExecutionEngine::newArrayBuffer(size_t length)
{
    return memoryManager->allocObject<ArrayBuffer>(length);
}


Heap::DateObject *ExecutionEngine::newDateObject(const Value &value)
{
    return memoryManager->allocObject<DateObject>(value);
}

Heap::DateObject *ExecutionEngine::newDateObject(const QDateTime &dt)
{
    Scope scope(this);
    Scoped<DateObject> object(scope, memoryManager->allocObject<DateObject>(dt));
    return object->d();
}

Heap::DateObject *ExecutionEngine::newDateObjectFromTime(const QTime &t)
{
    Scope scope(this);
    Scoped<DateObject> object(scope, memoryManager->allocObject<DateObject>(t));
    return object->d();
}

Heap::RegExpObject *ExecutionEngine::newRegExpObject(const QString &pattern, int flags)
{
    bool global = (flags & IR::RegExp::RegExp_Global);
    bool ignoreCase = false;
    bool multiline = false;
    if (flags & IR::RegExp::RegExp_IgnoreCase)
        ignoreCase = true;
    if (flags & IR::RegExp::RegExp_Multiline)
        multiline = true;

    Scope scope(this);
    Scoped<RegExp> re(scope, RegExp::create(this, pattern, ignoreCase, multiline));
    return newRegExpObject(re, global);
}

Heap::RegExpObject *ExecutionEngine::newRegExpObject(RegExp *re, bool global)
{
    return memoryManager->allocObject<RegExpObject>(re, global);
}

Heap::RegExpObject *ExecutionEngine::newRegExpObject(const QRegExp &re)
{
    return memoryManager->allocObject<RegExpObject>(re);
}

Heap::Object *ExecutionEngine::newErrorObject(const Value &value)
{
    return ErrorObject::create<ErrorObject>(this, value);
}

Heap::Object *ExecutionEngine::newSyntaxErrorObject(const QString &message)
{
    return ErrorObject::create<SyntaxErrorObject>(this, message);
}

Heap::Object *ExecutionEngine::newSyntaxErrorObject(const QString &message, const QString &fileName, int line, int column)
{
    return ErrorObject::create<SyntaxErrorObject>(this, message, fileName, line, column);
}


Heap::Object *ExecutionEngine::newReferenceErrorObject(const QString &message)
{
    return ErrorObject::create<ReferenceErrorObject>(this, message);
}

Heap::Object *ExecutionEngine::newReferenceErrorObject(const QString &message, const QString &fileName, int line, int column)
{
    return ErrorObject::create<ReferenceErrorObject>(this, message, fileName, line, column);
}


Heap::Object *ExecutionEngine::newTypeErrorObject(const QString &message)
{
    return ErrorObject::create<TypeErrorObject>(this, message);
}

Heap::Object *ExecutionEngine::newRangeErrorObject(const QString &message)
{
    return ErrorObject::create<RangeErrorObject>(this, message);
}

Heap::Object *ExecutionEngine::newURIErrorObject(const Value &message)
{
    return ErrorObject::create<URIErrorObject>(this, message);
}

Heap::Object *ExecutionEngine::newVariantObject(const QVariant &v)
{
    return memoryManager->allocObject<VariantObject>(v);
}

Heap::Object *ExecutionEngine::newForEachIteratorObject(Object *o)
{
    Scope scope(this);
    ScopedObject obj(scope, memoryManager->allocObject<ForEachIteratorObject>(o));
    return obj->d();
}

Heap::QmlContext *ExecutionEngine::qmlContext() const
{
    Heap::ExecutionContext *ctx = current;

    // get the correct context when we're within a builtin function
    if (ctx->type == Heap::ExecutionContext::Type_SimpleCallContext && !ctx->outer)
        ctx = parentContext(currentContext)->d();

    if (ctx->type != Heap::ExecutionContext::Type_QmlContext && !ctx->outer)
        return 0;

    while (ctx->outer && ctx->outer->type != Heap::ExecutionContext::Type_GlobalContext)
        ctx = ctx->outer;

    Q_ASSERT(ctx);
    if (ctx->type != Heap::ExecutionContext::Type_QmlContext)
        return 0;

    return static_cast<Heap::QmlContext *>(ctx);
}

QObject *ExecutionEngine::qmlScopeObject() const
{
    Heap::QmlContext *ctx = qmlContext();
    if (!ctx)
        return 0;

    return ctx->qml->scopeObject;
}

ReturnedValue ExecutionEngine::qmlSingletonWrapper(String *name)
{
    QQmlContextData *ctx = callingQmlContext();
    if (!ctx->imports)
        return Encode::undefined();
    // Search for attached properties, enums and imported scripts
    QQmlTypeNameCache::Result r = ctx->imports->query(name);

    Q_ASSERT(r.isValid());
    Q_ASSERT(r.type);
    Q_ASSERT(r.type->isSingleton());

    QQmlType::SingletonInstanceInfo *siinfo = r.type->singletonInstanceInfo();
    QQmlEngine *e = qmlEngine();
    siinfo->init(e);

    if (QObject *qobjectSingleton = siinfo->qobjectApi(e))
        return QV4::QObjectWrapper::wrap(this, qobjectSingleton);
    return QJSValuePrivate::convertedToValue(this, siinfo->scriptApi(e));
}

QQmlContextData *ExecutionEngine::callingQmlContext() const
{
    Heap::QmlContext *ctx = qmlContext();
    if (!ctx)
        return 0;

    return ctx->qml->context->contextData();
}

QVector<StackFrame> ExecutionEngine::stackTrace(int frameLimit) const
{
    Scope scope(const_cast<ExecutionEngine *>(this));
    ScopedString name(scope);
    QVector<StackFrame> stack;

    ExecutionContext *c = currentContext;
    ScopedFunctionObject function(scope);
    while (c && frameLimit) {
        function = c->getFunctionObject();
        if (function) {
            StackFrame frame;
            if (const Function *f = function->function())
                frame.source = f->sourceFile();
            name = function->name();
            frame.function = name->toQString();
            frame.line = -1;
            frame.column = -1;

            if (function->function())
                // line numbers can be negative for places where you can't set a real breakpoint
                frame.line = qAbs(c->d()->lineNumber);

            stack.append(frame);
            --frameLimit;
        }
        c = parentContext(c);
    }

    if (frameLimit && globalCode) {
        StackFrame frame;
        frame.source = globalCode->sourceFile();
        frame.function = globalCode->name()->toQString();
        frame.line = rootContext()->d()->lineNumber;
        frame.column = -1;

        stack.append(frame);
    }
    return stack;
}

StackFrame ExecutionEngine::currentStackFrame() const
{
    StackFrame frame;
    frame.line = -1;
    frame.column = -1;

    QVector<StackFrame> trace = stackTrace(/*limit*/ 1);
    if (!trace.isEmpty())
        frame = trace.first();

    return frame;
}

/* Helper and "C" linkage exported function to format a GDBMI stacktrace for
 * invocation by a debugger.
 * Sample GDB invocation: print qt_v4StackTrace((void*)0x7fffffffb290)
 * Sample CDB invocation: .call Qt5Qmld!qt_v4StackTrace(0x7fffffffb290) ; gh
 * Note: The helper is there to suppress MSVC warning 4190 about anything
 * with UDT return types in a "C" linkage function. */

static inline char *v4StackTrace(const ExecutionContext *context)
{
    QString result;
    QTextStream str(&result);
    str << "stack=[";
    if (context && context->d()->engine) {
        const QVector<StackFrame> stackTrace = context->d()->engine->stackTrace(20);
        for (int i = 0; i < stackTrace.size(); ++i) {
            if (i)
                str << ',';
            const QUrl url(stackTrace.at(i).source);
            const QString fileName = url.isLocalFile() ? url.toLocalFile() : url.toString();
            str << "frame={level=\"" << i << "\",func=\"" << stackTrace.at(i).function
                << "\",file=\"" << fileName << "\",fullname=\"" << fileName
                << "\",line=\"" << stackTrace.at(i).line << "\",language=\"js\"}";
        }
    }
    str << ']';
    return qstrdup(result.toLocal8Bit().constData());
}

extern "C" Q_QML_EXPORT char *qt_v4StackTrace(void *executionContext)
{
    return v4StackTrace(reinterpret_cast<const ExecutionContext *>(executionContext));
}

QUrl ExecutionEngine::resolvedUrl(const QString &file)
{
    QUrl src(file);
    if (!src.isRelative())
        return src;

    QUrl base;
    ExecutionContext *c = currentContext;
    while (c) {
        CallContext *callCtx = c->asCallContext();
        if (callCtx && callCtx->d()->function) {
            if (callCtx->d()->function->function)
                base.setUrl(callCtx->d()->function->function->sourceFile());
            break;
        }
        c = parentContext(c);
    }

    if (base.isEmpty() && globalCode)
        base.setUrl(globalCode->sourceFile());

    if (base.isEmpty())
        return src;

    return base.resolved(src);
}

void ExecutionEngine::requireArgumentsAccessors(int n)
{
    if (n <= nArgumentsAccessors)
        return;

    Scope scope(this);
    ScopedFunctionObject get(scope);
    ScopedFunctionObject set(scope);

    if (n >= nArgumentsAccessors) {
        Property *oldAccessors = argumentsAccessors;
        int oldSize = nArgumentsAccessors;
        nArgumentsAccessors = qMax(8, n);
        argumentsAccessors = new Property[nArgumentsAccessors];
        if (oldAccessors) {
            memcpy(argumentsAccessors, oldAccessors, oldSize*sizeof(Property));
            delete [] oldAccessors;
        }
        ExecutionContext *global = rootContext();
        for (int i = oldSize; i < nArgumentsAccessors; ++i) {
            argumentsAccessors[i].value = ScopedValue(scope, memoryManager->allocObject<ArgumentsGetterFunction>(global, i));
            argumentsAccessors[i].set = ScopedValue(scope, memoryManager->allocObject<ArgumentsSetterFunction>(global, i));
        }
    }
}

void ExecutionEngine::markObjects()
{
    identifierTable->mark(this);

    for (int i = 0; i < nArgumentsAccessors; ++i) {
        const Property &pd = argumentsAccessors[i];
        if (Heap::FunctionObject *getter = pd.getter())
            getter->mark(this);
        if (Heap::FunctionObject *setter = pd.setter())
            setter->mark(this);
    }

    classPool->markObjects(this);

    for (QSet<CompiledData::CompilationUnit*>::ConstIterator it = compilationUnits.constBegin(), end = compilationUnits.constEnd();
         it != end; ++it)
        (*it)->markObjects(this);
}

ReturnedValue ExecutionEngine::throwError(const Value &value)
{
    // we can get in here with an exception already set, as the runtime
    // doesn't check after every operation that can throw.
    // in this case preserve the first exception to give correct error
    // information
    if (hasException)
        return Encode::undefined();

    hasException = true;
    *exceptionValue = value;
    QV4::Scope scope(this);
    QV4::Scoped<ErrorObject> error(scope, value);
    if (!!error)
        exceptionStackTrace = *error->d()->stackTrace;
    else
        exceptionStackTrace = stackTrace();

    if (QV4::Debugging::Debugger *debug = debugger())
        debug->aboutToThrow();

    return Encode::undefined();
}

ReturnedValue ExecutionEngine::catchException(StackTrace *trace)
{
    Q_ASSERT(hasException);
    if (trace)
        *trace = exceptionStackTrace;
    exceptionStackTrace.clear();
    hasException = false;
    ReturnedValue res = exceptionValue->asReturnedValue();
    *exceptionValue = Primitive::emptyValue();
    return res;
}

ReturnedValue ExecutionEngine::throwError(const QString &message)
{
    Scope scope(this);
    ScopedValue v(scope, newString(message));
    v = newErrorObject(v);
    return throwError(v);
}

ReturnedValue ExecutionEngine::throwSyntaxError(const QString &message, const QString &fileName, int line, int column)
{
    Scope scope(this);
    ScopedObject error(scope, newSyntaxErrorObject(message, fileName, line, column));
    return throwError(error);
}

ReturnedValue ExecutionEngine::throwSyntaxError(const QString &message)
{
    Scope scope(this);
    ScopedObject error(scope, newSyntaxErrorObject(message));
    return throwError(error);
}


ReturnedValue ExecutionEngine::throwTypeError()
{
    Scope scope(this);
    ScopedObject error(scope, newTypeErrorObject(QStringLiteral("Type error")));
    return throwError(error);
}

ReturnedValue ExecutionEngine::throwTypeError(const QString &message)
{
    Scope scope(this);
    ScopedObject error(scope, newTypeErrorObject(message));
    return throwError(error);
}

ReturnedValue ExecutionEngine::throwReferenceError(const Value &value)
{
    Scope scope(this);
    ScopedString s(scope, value.toString(this));
    QString msg = s->toQString() + QLatin1String(" is not defined");
    ScopedObject error(scope, newReferenceErrorObject(msg));
    return throwError(error);
}

ReturnedValue ExecutionEngine::throwReferenceError(const QString &message, const QString &fileName, int line, int column)
{
    Scope scope(this);
    QString msg = message;
    ScopedObject error(scope, newReferenceErrorObject(msg, fileName, line, column));
    return throwError(error);
}

ReturnedValue ExecutionEngine::throwRangeError(const QString &message)
{
    Scope scope(this);
    ScopedObject error(scope, newRangeErrorObject(message));
    return throwError(error);
}

ReturnedValue ExecutionEngine::throwRangeError(const Value &value)
{
    Scope scope(this);
    ScopedString s(scope, value.toString(this));
    QString msg = s->toQString() + QLatin1String(" out of range");
    ScopedObject error(scope, newRangeErrorObject(msg));
    return throwError(error);
}

ReturnedValue ExecutionEngine::throwURIError(const Value &msg)
{
    Scope scope(this);
    ScopedObject error(scope, newURIErrorObject(msg));
    return throwError(error);
}

ReturnedValue ExecutionEngine::throwUnimplemented(const QString &message)
{
    Scope scope(this);
    ScopedValue v(scope, newString(QStringLiteral("Unimplemented ") + message));
    v = newErrorObject(v);
    return throwError(v);
}


QQmlError ExecutionEngine::catchExceptionAsQmlError()
{
    QV4::StackTrace trace;
    QV4::Scope scope(this);
    QV4::ScopedValue exception(scope, catchException(&trace));
    QQmlError error;
    if (!trace.isEmpty()) {
        QV4::StackFrame frame = trace.constFirst();
        error.setUrl(QUrl(frame.source));
        error.setLine(frame.line);
        error.setColumn(frame.column);
    }
    QV4::Scoped<QV4::ErrorObject> errorObj(scope, exception);
    if (!!errorObj && errorObj->asSyntaxError()) {
        QV4::ScopedString m(scope, newString(QStringLiteral("message")));
        QV4::ScopedValue v(scope, errorObj->get(m));
        error.setDescription(v->toQStringNoThrow());
    } else
        error.setDescription(exception->toQStringNoThrow());
    return error;
}

// Variant conversion code

typedef QSet<QV4::Heap::Object *> V4ObjectSet;
static QVariant toVariant(QV4::ExecutionEngine *e, const QV4::Value &value, int typeHint, bool createJSValueForObjects, V4ObjectSet *visitedObjects);
static QObject *qtObjectFromJS(QV4::ExecutionEngine *engine, const QV4::Value &value);
static QVariant objectToVariant(QV4::ExecutionEngine *e, const QV4::Object *o, V4ObjectSet *visitedObjects = 0);
static bool convertToNativeQObject(QV4::ExecutionEngine *e, const QV4::Value &value,
                            const QByteArray &targetType,
                            void **result);
static QV4::ReturnedValue variantListToJS(QV4::ExecutionEngine *v4, const QVariantList &lst);
static QV4::ReturnedValue variantMapToJS(QV4::ExecutionEngine *v4, const QVariantMap &vmap);
static QV4::ReturnedValue variantToJS(QV4::ExecutionEngine *v4, const QVariant &value)
{
    return v4->metaTypeToJS(value.userType(), value.constData());
}


QVariant ExecutionEngine::toVariant(const Value &value, int typeHint, bool createJSValueForObjects)
{
    return ::toVariant(this, value, typeHint, createJSValueForObjects, 0);
}


static QVariant toVariant(QV4::ExecutionEngine *e, const QV4::Value &value, int typeHint, bool createJSValueForObjects, V4ObjectSet *visitedObjects)
{
    Q_ASSERT (!value.isEmpty());
    QV4::Scope scope(e);

    if (const QV4::VariantObject *v = value.as<QV4::VariantObject>())
        return v->d()->data();

    if (typeHint == QVariant::Bool)
        return QVariant(value.toBoolean());

    if (typeHint == QMetaType::QJsonValue)
        return QVariant::fromValue(QV4::JsonObject::toJsonValue(value));

    if (typeHint == qMetaTypeId<QJSValue>())
        return QVariant::fromValue(QJSValue(e, value.asReturnedValue()));

    if (value.as<Object>()) {
        QV4::ScopedObject object(scope, value);
        if (typeHint == QMetaType::QJsonObject
                   && !value.as<ArrayObject>() && !value.as<FunctionObject>()) {
            return QVariant::fromValue(QV4::JsonObject::toJsonObject(object));
        } else if (QV4::QObjectWrapper *wrapper = object->as<QV4::QObjectWrapper>()) {
            return qVariantFromValue<QObject *>(wrapper->object());
        } else if (object->as<QV4::QmlContextWrapper>()) {
            return QVariant();
        } else if (QV4::QmlTypeWrapper *w = object->as<QV4::QmlTypeWrapper>()) {
            return w->toVariant();
        } else if (QV4::QQmlValueTypeWrapper *v = object->as<QV4::QQmlValueTypeWrapper>()) {
            return v->toVariant();
        } else if (QV4::QmlListWrapper *l = object->as<QV4::QmlListWrapper>()) {
            return l->toVariant();
        } else if (object->isListType())
            return QV4::SequencePrototype::toVariant(object);
    }

    if (value.as<ArrayObject>()) {
        QV4::ScopedArrayObject a(scope, value);
        if (typeHint == qMetaTypeId<QList<QObject *> >()) {
            QList<QObject *> list;
            uint length = a->getLength();
            QV4::Scoped<QV4::QObjectWrapper> qobjectWrapper(scope);
            for (uint ii = 0; ii < length; ++ii) {
                qobjectWrapper = a->getIndexed(ii);
                if (!!qobjectWrapper) {
                    list << qobjectWrapper->object();
                } else {
                    list << 0;
                }
            }

            return qVariantFromValue<QList<QObject*> >(list);
        } else if (typeHint == QMetaType::QJsonArray) {
            return QVariant::fromValue(QV4::JsonObject::toJsonArray(a));
        }

        bool succeeded = false;
        QVariant retn = QV4::SequencePrototype::toVariant(value, typeHint, &succeeded);
        if (succeeded)
            return retn;
    }

    if (value.isUndefined())
        return QVariant();
    if (value.isNull())
        return QVariant::fromValue(nullptr);
    if (value.isBoolean())
        return value.booleanValue();
    if (value.isInteger())
        return value.integerValue();
    if (value.isNumber())
        return value.asDouble();
    if (String *s = value.stringValue()) {
        const QString &str = s->toQString();
        // QChars are stored as a strings
        if (typeHint == QVariant::Char && str.size() == 1)
            return str.at(0);
        return str;
    }
    if (const QV4::QQmlLocaleData *ld = value.as<QV4::QQmlLocaleData>())
        return *ld->d()->locale;
    if (const QV4::DateObject *d = value.as<DateObject>())
        return d->toQDateTime();
    if (const ArrayBuffer *d = value.as<ArrayBuffer>())
        return d->asByteArray();
    // NOTE: since we convert QTime to JS Date, round trip will change the variant type (to QDateTime)!

    QV4::ScopedObject o(scope, value);
    Q_ASSERT(o);

    if (QV4::RegExpObject *re = o->as<QV4::RegExpObject>())
        return re->toQRegExp();

    if (createJSValueForObjects)
        return QVariant::fromValue(QJSValue(scope.engine, o->asReturnedValue()));

    return objectToVariant(e, o, visitedObjects);
}

static QVariant objectToVariant(QV4::ExecutionEngine *e, const QV4::Object *o, V4ObjectSet *visitedObjects)
{
    Q_ASSERT(o);

    V4ObjectSet recursionGuardSet;
    if (!visitedObjects) {
        visitedObjects = &recursionGuardSet;
    } else if (visitedObjects->contains(o->d())) {
        // Avoid recursion.
        // For compatibility with QVariant{List,Map} conversion, we return an
        // empty object (and no error is thrown).
        if (o->as<ArrayObject>())
            return QVariantList();
        return QVariantMap();
    }
    visitedObjects->insert(o->d());

    QVariant result;

    if (o->as<ArrayObject>()) {
        QV4::Scope scope(e);
        QV4::ScopedArrayObject a(scope, o->asReturnedValue());
        QV4::ScopedValue v(scope);
        QVariantList list;

        int length = a->getLength();
        for (int ii = 0; ii < length; ++ii) {
            v = a->getIndexed(ii);
            list << ::toVariant(e, v, -1, /*createJSValueForObjects*/false, visitedObjects);
        }

        result = list;
    } else if (!o->as<FunctionObject>()) {
        QVariantMap map;
        QV4::Scope scope(e);
        QV4::ObjectIterator it(scope, o, QV4::ObjectIterator::EnumerableOnly);
        QV4::ScopedValue name(scope);
        QV4::ScopedValue val(scope);
        while (1) {
            name = it.nextPropertyNameAsString(val);
            if (name->isNull())
                break;

            QString key = name->toQStringNoThrow();
            map.insert(key, ::toVariant(e, val, /*type hint*/-1, /*createJSValueForObjects*/false, visitedObjects));
        }

        result = map;
    }

    visitedObjects->remove(o->d());
    return result;
}

static QV4::ReturnedValue arrayFromVariantList(QV4::ExecutionEngine *e, const QVariantList &list)
{
    QV4::Scope scope(e);
    QV4::ScopedArrayObject a(scope, e->newArrayObject());
    int len = list.count();
    a->arrayReserve(len);
    QV4::ScopedValue v(scope);
    for (int ii = 0; ii < len; ++ii)
        a->arrayPut(ii, (v = scope.engine->fromVariant(list.at(ii))));

    a->setArrayLengthUnchecked(len);
    return a.asReturnedValue();
}

static QV4::ReturnedValue objectFromVariantMap(QV4::ExecutionEngine *e, const QVariantMap &map)
{
    QV4::Scope scope(e);
    QV4::ScopedObject o(scope, e->newObject());
    QV4::ScopedString s(scope);
    QV4::ScopedValue v(scope);
    for (QVariantMap::const_iterator iter = map.begin(), cend = map.end(); iter != cend; ++iter) {
        s = e->newString(iter.key());
        uint idx = s->asArrayIndex();
        if (idx > 16 && (!o->arrayData() || idx > o->arrayData()->length() * 2))
            o->initSparseArray();
        o->put(s, (v = e->fromVariant(iter.value())));
    }
    return o.asReturnedValue();
}

Q_CORE_EXPORT QString qt_regexp_toCanonical(const QString &, QRegExp::PatternSyntax);

QV4::ReturnedValue QV4::ExecutionEngine::fromVariant(const QVariant &variant)
{
    int type = variant.userType();
    const void *ptr = variant.constData();

    if (type < QMetaType::User) {
        switch (QMetaType::Type(type)) {
            case QMetaType::UnknownType:
            case QMetaType::Void:
                return QV4::Encode::undefined();
            case QMetaType::Nullptr:
            case QMetaType::VoidStar:
                return QV4::Encode::null();
            case QMetaType::Bool:
                return QV4::Encode(*reinterpret_cast<const bool*>(ptr));
            case QMetaType::Int:
                return QV4::Encode(*reinterpret_cast<const int*>(ptr));
            case QMetaType::UInt:
                return QV4::Encode(*reinterpret_cast<const uint*>(ptr));
            case QMetaType::LongLong:
                return QV4::Encode((double)*reinterpret_cast<const qlonglong*>(ptr));
            case QMetaType::ULongLong:
                return QV4::Encode((double)*reinterpret_cast<const qulonglong*>(ptr));
            case QMetaType::Double:
                return QV4::Encode(*reinterpret_cast<const double*>(ptr));
            case QMetaType::QString:
                return newString(*reinterpret_cast<const QString*>(ptr))->asReturnedValue();
            case QMetaType::QByteArray:
                return newArrayBuffer(*reinterpret_cast<const QByteArray*>(ptr))->asReturnedValue();
            case QMetaType::Float:
                return QV4::Encode(*reinterpret_cast<const float*>(ptr));
            case QMetaType::Short:
                return QV4::Encode((int)*reinterpret_cast<const short*>(ptr));
            case QMetaType::UShort:
                return QV4::Encode((int)*reinterpret_cast<const unsigned short*>(ptr));
            case QMetaType::Char:
                return QV4::Encode((int)*reinterpret_cast<const char*>(ptr));
            case QMetaType::UChar:
                return QV4::Encode((int)*reinterpret_cast<const unsigned char*>(ptr));
            case QMetaType::QChar:
                return newString(*reinterpret_cast<const QChar *>(ptr))->asReturnedValue();
            case QMetaType::QDateTime:
                return QV4::Encode(newDateObject(*reinterpret_cast<const QDateTime *>(ptr)));
            case QMetaType::QDate:
                return QV4::Encode(newDateObject(QDateTime(*reinterpret_cast<const QDate *>(ptr))));
            case QMetaType::QTime:
                return QV4::Encode(newDateObjectFromTime(*reinterpret_cast<const QTime *>(ptr)));
            case QMetaType::QRegExp:
                return QV4::Encode(newRegExpObject(*reinterpret_cast<const QRegExp *>(ptr)));
            case QMetaType::QObjectStar:
                return QV4::QObjectWrapper::wrap(this, *reinterpret_cast<QObject* const *>(ptr));
            case QMetaType::QStringList:
                {
                bool succeeded = false;
                QV4::Scope scope(this);
                QV4::ScopedValue retn(scope, QV4::SequencePrototype::fromVariant(this, variant, &succeeded));
                if (succeeded)
                    return retn->asReturnedValue();
                return QV4::Encode(newArrayObject(*reinterpret_cast<const QStringList *>(ptr)));
                }
            case QMetaType::QVariantList:
                return arrayFromVariantList(this, *reinterpret_cast<const QVariantList *>(ptr));
            case QMetaType::QVariantMap:
                return objectFromVariantMap(this, *reinterpret_cast<const QVariantMap *>(ptr));
            case QMetaType::QJsonValue:
                return QV4::JsonObject::fromJsonValue(this, *reinterpret_cast<const QJsonValue *>(ptr));
            case QMetaType::QJsonObject:
                return QV4::JsonObject::fromJsonObject(this, *reinterpret_cast<const QJsonObject *>(ptr));
            case QMetaType::QJsonArray:
                return QV4::JsonObject::fromJsonArray(this, *reinterpret_cast<const QJsonArray *>(ptr));
            case QMetaType::QLocale:
                return QQmlLocale::wrap(this, *reinterpret_cast<const QLocale*>(ptr));
            default:
                break;
        }

        if (const QMetaObject *vtmo = QQmlValueTypeFactory::metaObjectForMetaType(type))
            return QV4::QQmlValueTypeWrapper::create(this, variant, vtmo, type);
    } else {
        QV4::Scope scope(this);
        if (type == qMetaTypeId<QQmlListReference>()) {
            typedef QQmlListReferencePrivate QDLRP;
            QDLRP *p = QDLRP::get((QQmlListReference*)const_cast<void *>(ptr));
            if (p->object) {
                return QV4::QmlListWrapper::create(scope.engine, p->property, p->propertyType);
            } else {
                return QV4::Encode::null();
            }
        } else if (type == qMetaTypeId<QJSValue>()) {
            const QJSValue *value = reinterpret_cast<const QJSValue *>(ptr);
            return QJSValuePrivate::convertedToValue(this, *value);
        } else if (type == qMetaTypeId<QList<QObject *> >()) {
            // XXX Can this be made more by using Array as a prototype and implementing
            // directly against QList<QObject*>?
            const QList<QObject *> &list = *(const QList<QObject *>*)ptr;
            QV4::ScopedArrayObject a(scope, newArrayObject());
            a->arrayReserve(list.count());
            QV4::ScopedValue v(scope);
            for (int ii = 0; ii < list.count(); ++ii)
                a->arrayPut(ii, (v = QV4::QObjectWrapper::wrap(this, list.at(ii))));
            a->setArrayLengthUnchecked(list.count());
            return a.asReturnedValue();
        } else if (QMetaType::typeFlags(type) & QMetaType::PointerToQObject) {
            return QV4::QObjectWrapper::wrap(this, *reinterpret_cast<QObject* const *>(ptr));
        }

        bool objOk;
        QObject *obj = QQmlMetaType::toQObject(variant, &objOk);
        if (objOk)
            return QV4::QObjectWrapper::wrap(this, obj);

        bool succeeded = false;
        QV4::ScopedValue retn(scope, QV4::SequencePrototype::fromVariant(this, variant, &succeeded));
        if (succeeded)
            return retn->asReturnedValue();

        if (const QMetaObject *vtmo = QQmlValueTypeFactory::metaObjectForMetaType(type))
            return QV4::QQmlValueTypeWrapper::create(this, variant, vtmo, type);
    }

    // XXX TODO: To be compatible, we still need to handle:
    //    + QObjectList
    //    + QList<int>

    return QV4::Encode(newVariantObject(variant));
}

QVariantMap ExecutionEngine::variantMapFromJS(const Object *o)
{
    return objectToVariant(this, o).toMap();
}


// Converts a QVariantList to JS.
// The result is a new Array object with length equal to the length
// of the QVariantList, and the elements being the QVariantList's
// elements converted to JS, recursively.
static QV4::ReturnedValue variantListToJS(QV4::ExecutionEngine *v4, const QVariantList &lst)
{
    QV4::Scope scope(v4);
    QV4::ScopedArrayObject a(scope, v4->newArrayObject());
    a->arrayReserve(lst.size());
    QV4::ScopedValue v(scope);
    for (int i = 0; i < lst.size(); i++)
        a->arrayPut(i, (v = variantToJS(v4, lst.at(i))));
    a->setArrayLengthUnchecked(lst.size());
    return a.asReturnedValue();
}

// Converts a QVariantMap to JS.
// The result is a new Object object with property names being
// the keys of the QVariantMap, and values being the values of
// the QVariantMap converted to JS, recursively.
static QV4::ReturnedValue variantMapToJS(QV4::ExecutionEngine *v4, const QVariantMap &vmap)
{
    QV4::Scope scope(v4);
    QV4::ScopedObject o(scope, v4->newObject());
    QV4::ScopedString s(scope);
    QV4::ScopedValue v(scope);
    for (QVariantMap::const_iterator it = vmap.constBegin(), cend = vmap.constEnd(); it != cend; ++it) {
        s = v4->newIdentifier(it.key());
        v = variantToJS(v4, it.value());
        uint idx = s->asArrayIndex();
        if (idx < UINT_MAX)
            o->arraySet(idx, v);
        else
            o->insertMember(s, v);
    }
    return o.asReturnedValue();
}

// Converts the meta-type defined by the given type and data to JS.
// Returns the value if conversion succeeded, an empty handle otherwise.
QV4::ReturnedValue ExecutionEngine::metaTypeToJS(int type, const void *data)
{
    Q_ASSERT(data != 0);

    // check if it's one of the types we know
    switch (QMetaType::Type(type)) {
    case QMetaType::UnknownType:
    case QMetaType::Void:
        return QV4::Encode::undefined();
    case QMetaType::Nullptr:
    case QMetaType::VoidStar:
        return QV4::Encode::null();
    case QMetaType::Bool:
        return QV4::Encode(*reinterpret_cast<const bool*>(data));
    case QMetaType::Int:
        return QV4::Encode(*reinterpret_cast<const int*>(data));
    case QMetaType::UInt:
        return QV4::Encode(*reinterpret_cast<const uint*>(data));
    case QMetaType::LongLong:
        return QV4::Encode(double(*reinterpret_cast<const qlonglong*>(data)));
    case QMetaType::ULongLong:
#if defined(Q_OS_WIN) && defined(_MSC_FULL_VER) && _MSC_FULL_VER <= 12008804
#pragma message("** NOTE: You need the Visual Studio Processor Pack to compile support for 64bit unsigned integers.")
        return QV4::Encode(double((qlonglong)*reinterpret_cast<const qulonglong*>(data)));
#elif defined(Q_CC_MSVC) && !defined(Q_CC_MSVC_NET)
        return QV4::Encode(double((qlonglong)*reinterpret_cast<const qulonglong*>(data)));
#else
        return QV4::Encode(double(*reinterpret_cast<const qulonglong*>(data)));
#endif
    case QMetaType::Double:
        return QV4::Encode(*reinterpret_cast<const double*>(data));
    case QMetaType::QString:
        return newString(*reinterpret_cast<const QString*>(data))->asReturnedValue();
    case QMetaType::QByteArray:
        return newArrayBuffer(*reinterpret_cast<const QByteArray*>(data))->asReturnedValue();
    case QMetaType::Float:
        return QV4::Encode(*reinterpret_cast<const float*>(data));
    case QMetaType::Short:
        return QV4::Encode((int)*reinterpret_cast<const short*>(data));
    case QMetaType::UShort:
        return QV4::Encode((int)*reinterpret_cast<const unsigned short*>(data));
    case QMetaType::Char:
        return QV4::Encode((int)*reinterpret_cast<const char*>(data));
    case QMetaType::UChar:
        return QV4::Encode((int)*reinterpret_cast<const unsigned char*>(data));
    case QMetaType::QChar:
        return QV4::Encode((int)(*reinterpret_cast<const QChar*>(data)).unicode());
    case QMetaType::QStringList:
        return QV4::Encode(newArrayObject(*reinterpret_cast<const QStringList *>(data)));
    case QMetaType::QVariantList:
        return variantListToJS(this, *reinterpret_cast<const QVariantList *>(data));
    case QMetaType::QVariantMap:
        return variantMapToJS(this, *reinterpret_cast<const QVariantMap *>(data));
    case QMetaType::QDateTime:
        return QV4::Encode(newDateObject(*reinterpret_cast<const QDateTime *>(data)));
    case QMetaType::QDate:
        return QV4::Encode(newDateObject(QDateTime(*reinterpret_cast<const QDate *>(data))));
    case QMetaType::QRegExp:
        return QV4::Encode(newRegExpObject(*reinterpret_cast<const QRegExp *>(data)));
    case QMetaType::QObjectStar:
        return QV4::QObjectWrapper::wrap(this, *reinterpret_cast<QObject* const *>(data));
    case QMetaType::QVariant:
        return variantToJS(this, *reinterpret_cast<const QVariant*>(data));
    case QMetaType::QJsonValue:
        return QV4::JsonObject::fromJsonValue(this, *reinterpret_cast<const QJsonValue *>(data));
    case QMetaType::QJsonObject:
        return QV4::JsonObject::fromJsonObject(this, *reinterpret_cast<const QJsonObject *>(data));
    case QMetaType::QJsonArray:
        return QV4::JsonObject::fromJsonArray(this, *reinterpret_cast<const QJsonArray *>(data));
    default:
        if (type == qMetaTypeId<QJSValue>()) {
            return QJSValuePrivate::convertedToValue(this, *reinterpret_cast<const QJSValue*>(data));
        } else {
            QByteArray typeName = QMetaType::typeName(type);
            if (typeName.endsWith('*') && !*reinterpret_cast<void* const *>(data)) {
                return QV4::Encode::null();
            }
            QMetaType mt(type);
            if (mt.flags() & QMetaType::IsGadget) {
                Q_ASSERT(mt.metaObject());
                return QV4::QQmlValueTypeWrapper::create(this, QVariant(type, data), mt.metaObject(), type);
            }
            // Fall back to wrapping in a QVariant.
            return QV4::Encode(newVariantObject(QVariant(type, data)));
        }
    }
    Q_UNREACHABLE();
    return 0;
}

void ExecutionEngine::assertObjectBelongsToEngine(const Heap::Base &baseObject)
{
    Q_ASSERT(!baseObject.vtable()->isObject || static_cast<const Heap::Object&>(baseObject).internalClass->engine == this);
    Q_UNUSED(baseObject);
}

void ExecutionEngine::failStackLimitCheck(Scope &scope)
{
    scope.result = throwRangeError(QStringLiteral("Maximum call stack size exceeded."));
}

// Converts a JS value to a meta-type.
// data must point to a place that can store a value of the given type.
// Returns true if conversion succeeded, false otherwise.
bool ExecutionEngine::metaTypeFromJS(const Value *value, int type, void *data)
{
    // check if it's one of the types we know
    switch (QMetaType::Type(type)) {
    case QMetaType::Bool:
        *reinterpret_cast<bool*>(data) = value->toBoolean();
        return true;
    case QMetaType::Int:
        *reinterpret_cast<int*>(data) = value->toInt32();
        return true;
    case QMetaType::UInt:
        *reinterpret_cast<uint*>(data) = value->toUInt32();
        return true;
    case QMetaType::LongLong:
        *reinterpret_cast<qlonglong*>(data) = qlonglong(value->toInteger());
        return true;
    case QMetaType::ULongLong:
        *reinterpret_cast<qulonglong*>(data) = qulonglong(value->toInteger());
        return true;
    case QMetaType::Double:
        *reinterpret_cast<double*>(data) = value->toNumber();
        return true;
    case QMetaType::QString:
        if (value->isUndefined() || value->isNull())
            *reinterpret_cast<QString*>(data) = QString();
        else
            *reinterpret_cast<QString*>(data) = value->toQString();
        return true;
    case QMetaType::QByteArray:
        if (const ArrayBuffer *ab = value->as<ArrayBuffer>())
            *reinterpret_cast<QByteArray*>(data) = ab->asByteArray();
        else
            *reinterpret_cast<QByteArray*>(data) = QByteArray();
        return true;
    case QMetaType::Float:
        *reinterpret_cast<float*>(data) = value->toNumber();
        return true;
    case QMetaType::Short:
        *reinterpret_cast<short*>(data) = short(value->toInt32());
        return true;
    case QMetaType::UShort:
        *reinterpret_cast<unsigned short*>(data) = value->toUInt16();
        return true;
    case QMetaType::Char:
        *reinterpret_cast<char*>(data) = char(value->toInt32());
        return true;
    case QMetaType::UChar:
        *reinterpret_cast<unsigned char*>(data) = (unsigned char)(value->toInt32());
        return true;
    case QMetaType::QChar:
        if (String *s = value->stringValue()) {
            QString str = s->toQString();
            *reinterpret_cast<QChar*>(data) = str.isEmpty() ? QChar() : str.at(0);
        } else {
            *reinterpret_cast<QChar*>(data) = QChar(ushort(value->toUInt16()));
        }
        return true;
    case QMetaType::QDateTime:
        if (const QV4::DateObject *d = value->as<DateObject>()) {
            *reinterpret_cast<QDateTime *>(data) = d->toQDateTime();
            return true;
        } break;
    case QMetaType::QDate:
        if (const QV4::DateObject *d = value->as<DateObject>()) {
            *reinterpret_cast<QDate *>(data) = d->toQDateTime().date();
            return true;
        } break;
    case QMetaType::QRegExp:
        if (const QV4::RegExpObject *r = value->as<QV4::RegExpObject>()) {
            *reinterpret_cast<QRegExp *>(data) = r->toQRegExp();
            return true;
        } break;
    case QMetaType::QObjectStar: {
        const QV4::QObjectWrapper *qobjectWrapper = value->as<QV4::QObjectWrapper>();
        if (qobjectWrapper || value->isNull()) {
            *reinterpret_cast<QObject* *>(data) = qtObjectFromJS(this, *value);
            return true;
        } break;
    }
    case QMetaType::QStringList: {
        const QV4::ArrayObject *a = value->as<QV4::ArrayObject>();
        if (a) {
            *reinterpret_cast<QStringList *>(data) = a->toQStringList();
            return true;
        }
        break;
    }
    case QMetaType::QVariantList: {
        const QV4::ArrayObject *a = value->as<QV4::ArrayObject>();
        if (a) {
            *reinterpret_cast<QVariantList *>(data) = toVariant(*a, /*typeHint*/-1, /*createJSValueForObjects*/false).toList();
            return true;
        }
        break;
    }
    case QMetaType::QVariantMap: {
        const QV4::Object *o = value->as<QV4::Object>();
        if (o) {
            *reinterpret_cast<QVariantMap *>(data) = variantMapFromJS(o);
            return true;
        }
        break;
    }
    case QMetaType::QVariant:
        *reinterpret_cast<QVariant*>(data) = toVariant(*value, /*typeHint*/-1, /*createJSValueForObjects*/false);
        return true;
    case QMetaType::QJsonValue:
        *reinterpret_cast<QJsonValue *>(data) = QV4::JsonObject::toJsonValue(*value);
        return true;
    case QMetaType::QJsonObject: {
        *reinterpret_cast<QJsonObject *>(data) = QV4::JsonObject::toJsonObject(value->as<Object>());
        return true;
    }
    case QMetaType::QJsonArray: {
        const QV4::ArrayObject *a = value->as<ArrayObject>();
        if (a) {
            *reinterpret_cast<QJsonArray *>(data) = JsonObject::toJsonArray(a);
            return true;
        }
        break;
    }
    default:
    ;
    }

    {
        const QQmlValueTypeWrapper *vtw = value->as<QQmlValueTypeWrapper>();
        if (vtw && vtw->typeId() == type) {
            return vtw->toGadget(data);
        }
    }

#if 0
    if (isQtVariant(value)) {
        const QVariant &var = variantValue(value);
        // ### Enable once constructInPlace() is in qt master.
        if (var.userType() == type) {
            QMetaType::constructInPlace(type, data, var.constData());
            return true;
        }
        if (var.canConvert(type)) {
            QVariant vv = var;
            vv.convert(type);
            Q_ASSERT(vv.userType() == type);
            QMetaType::constructInPlace(type, data, vv.constData());
            return true;
        }

    }
#endif

    // Try to use magic; for compatibility with qjsvalue_cast.

    QByteArray name = QMetaType::typeName(type);
    if (convertToNativeQObject(this, *value, name, reinterpret_cast<void* *>(data)))
        return true;
    if (value->as<QV4::VariantObject>() && name.endsWith('*')) {
        int valueType = QMetaType::type(name.left(name.size()-1));
        QVariant &var = value->as<QV4::VariantObject>()->d()->data();
        if (valueType == var.userType()) {
            // We have T t, T* is requested, so return &t.
            *reinterpret_cast<void* *>(data) = var.data();
            return true;
        } else if (Object *o = value->objectValue()) {
            // Look in the prototype chain.
            QV4::Scope scope(this);
            QV4::ScopedObject proto(scope, o->prototype());
            while (proto) {
                bool canCast = false;
                if (QV4::VariantObject *vo = proto->as<QV4::VariantObject>()) {
                    const QVariant &v = vo->d()->data();
                    canCast = (type == v.userType()) || (valueType && (valueType == v.userType()));
                }
                else if (proto->as<QV4::QObjectWrapper>()) {
                    QByteArray className = name.left(name.size()-1);
                    QV4::ScopedObject p(scope, proto.getPointer());
                    if (QObject *qobject = qtObjectFromJS(this, p))
                        canCast = qobject->qt_metacast(className) != 0;
                }
                if (canCast) {
                    QByteArray varTypeName = QMetaType::typeName(var.userType());
                    if (varTypeName.endsWith('*'))
                        *reinterpret_cast<void* *>(data) = *reinterpret_cast<void* *>(var.data());
                    else
                        *reinterpret_cast<void* *>(data) = var.data();
                    return true;
                }
                proto = proto->prototype();
            }
        }
    } else if (value->isNull() && name.endsWith('*')) {
        *reinterpret_cast<void* *>(data) = 0;
        return true;
    } else if (type == qMetaTypeId<QJSValue>()) {
        *reinterpret_cast<QJSValue*>(data) = QJSValue(this, value->asReturnedValue());
        return true;
    }

    return false;
}

static bool convertToNativeQObject(QV4::ExecutionEngine *e, const Value &value, const QByteArray &targetType, void **result)
{
    if (!targetType.endsWith('*'))
        return false;
    if (QObject *qobject = qtObjectFromJS(e, value)) {
        int start = targetType.startsWith("const ") ? 6 : 0;
        QByteArray className = targetType.mid(start, targetType.size()-start-1);
        if (void *instance = qobject->qt_metacast(className)) {
            *result = instance;
            return true;
        }
    }
    return false;
}

static QObject *qtObjectFromJS(QV4::ExecutionEngine *engine, const Value &value)
{
    if (!value.isObject())
        return 0;

    QV4::Scope scope(engine);
    QV4::Scoped<QV4::VariantObject> v(scope, value);

    if (v) {
        QVariant variant = v->d()->data();
        int type = variant.userType();
        if (type == QMetaType::QObjectStar)
            return *reinterpret_cast<QObject* const *>(variant.constData());
    }
    QV4::Scoped<QV4::QObjectWrapper> wrapper(scope, value);
    if (!wrapper)
        return 0;
    return wrapper->object();
}


QT_END_NAMESPACE