qqmltypewrapper.cpp

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// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
// Qt-Security score:significant
 
#include "qqmltypewrapper_p.h"
 
#include <private/qjsvalue_p.h>
 
#include <private/qqmlcontext_p.h>
#include <private/qqmlengine_p.h>
#include <private/qqmlmetaobject_p.h>
#include <private/qqmltypedata_p.h>
#include <private/qqmlvaluetypewrapper_p.h>
 
#include <private/qv4dateobject_p.h>
#include <private/qv4identifiertable_p.h>
#include <private/qv4lookup_p.h>
#include <private/qv4objectproto_p.h>
#include <private/qv4qobjectwrapper_p.h>
#include <private/qv4symbol_p.h>
#include <private/qv4urlobject_p.h>
#include <private/qv4variantobject_p.h>
 
QT_BEGIN_NAMESPACE
 
using namespace QV4;
 
DEFINE_OBJECT_VTABLE(QQmlTypeWrapper);
DEFINE_OBJECT_VTABLE(QQmlTypeConstructor);
DEFINE_OBJECT_VTABLE(QQmlEnumWrapper);
 
 
void Heap::QQmlTypeWrapper::init(TypeNameMode m, QObject *o, const QQmlTypePrivate *type)
{
    Q_ASSERT(type);
    FunctionObject::init();
    flags = quint8(m) | quint8(Type);
    object.init(o);
    QQmlType::refHandle(type);
    t.typePrivate = type;
}
 
void Heap::QQmlTypeWrapper::init(
        TypeNameMode m, QObject *o, QQmlTypeNameCache *type, const QQmlImportRef *import)
{
    Q_ASSERT(type);
    FunctionObject::init();
    flags = quint8(m) | quint8(Namespace);
    object.init(o);
    n.typeNamespace = type;
    n.typeNamespace->addref();
    n.importNamespace = import;
}
 
void Heap::QQmlTypeWrapper::destroy()
{
    switch (kind()) {
    case Type:
        Q_ASSERT(t.typePrivate);
        QQmlType::derefHandle(t.typePrivate);
        delete[] t.constructors;
        break;
    case Namespace:
        Q_ASSERT(n.typeNamespace);
        n.typeNamespace->release();
        break;
    }
 
    object.destroy();
    FunctionObject::destroy();
}
 
QQmlType Heap::QQmlTypeWrapper::type() const
{
    switch (kind()) {
    case Type:
        return QQmlType(t.typePrivate);
    case Namespace:
        return QQmlType();
    }
 
    Q_UNREACHABLE_RETURN(QQmlType());
}
 
QQmlTypeNameCache::Result Heap::QQmlTypeWrapper::queryNamespace(
        const QV4::String *name, QV4::ExecutionEngine *engine) const
{
    Q_ASSERT(kind() == Namespace);
    Q_ASSERT(n.typeNamespace);
    Q_ASSERT(n.importNamespace);
    return n.typeNamespace->query(name, n.importNamespace, engine->typeLoader());
 
}
 
template<typename Callback>
void warnWithLocation(const Heap::QQmlTypeWrapper *wrapper, Callback &&callback)
{
    auto log = qWarning().noquote().nospace();
    if (const CppStackFrame *frame = wrapper->internalClass->engine->currentStackFrame)
        log << frame->source() << ':' << frame->lineNumber() << ':';
    callback(log.space());
}
 
void Heap::QQmlTypeWrapper::warnIfUncreatable() const
{
    const QQmlType t = type();
    Q_ASSERT(t.isValid());
 
    if (t.isValueType())
        return;
 
    if (t.isSingleton()) {
        warnWithLocation(this, [&](QDebug &log) {
            log << "You are calling a Q_INVOKABLE constructor of" << t.typeName()
                << "which is a singleton in QML.";
        });
        return;
    }
 
    if (!t.isCreatable()) {
        warnWithLocation(this, [&](QDebug &log) {
            log << "You are calling a Q_INVOKABLE constructor of" << t.typeName()
                << "which is uncreatable in QML.";
        });
    }
}
 
bool QQmlTypeWrapper::isSingleton() const
{
    return d()->type().isSingleton();
}
 
const QMetaObject *QQmlTypeWrapper::metaObject() const
{
    const QQmlType type = d()->type();
    if (!type.isValid())
        return nullptr;
 
    if (type.isSingleton()) {
        auto metaObjectCandidate = type.metaObject();
        // if the candidate is the same as te baseMetaObject, we know that
        // we don't have an extended singleton; in that case the
        // actual instance might be subclass of type instead of type itself
        // so we need to query the actual object for it's meta-object
        if (metaObjectCandidate == type.baseMetaObject()) {
            QQmlEnginePrivate *qmlEngine = QQmlEnginePrivate::get(engine()->qmlEngine());
            auto object = qmlEngine->singletonInstance<QObject *>(type);
            if (object)
                return object->metaObject();
        }
        /* if we instead have an extended singleton, the dynamic proxy
           meta-object must alreday be set up correctly
          ### TODO: it isn't, as QQmlTypePrivate::init has no way to
                    query the object
        */
        return metaObjectCandidate;
    }
 
    return type.attachedPropertiesType(engine()->typeLoader());
}
 
QObject *QQmlTypeWrapper::object() const
{
    const QQmlType type = d()->type();
    if (!type.isValid())
        return nullptr;
 
    if (type.isSingleton())
        return QQmlEnginePrivate::get(engine()->qmlEngine())->singletonInstance<QObject *>(type);
 
    return qmlAttachedPropertiesObject(
            d()->object,
            type.attachedPropertiesFunction(engine()->typeLoader()));
}
 
QObject* QQmlTypeWrapper::singletonObject() const
{
    if (!isSingleton())
        return nullptr;
 
    QQmlEnginePrivate *e = QQmlEnginePrivate::get(engine()->qmlEngine());
    return e->singletonInstance<QObject*>(d()->type());
}
 
QVariant QQmlTypeWrapper::toVariant() const
{
    const QQmlType type = d()->type();
 
    // A QQmlTypeWrapper can represent a type namespace.
    // In that case there is no sensible C++ representation. Wrap a QJSValue.
    if (!type.isValid())
        return QVariant::fromValue(QJSValuePrivate::fromReturnedValue(asReturnedValue()));
 
    if (!isSingleton()) {
        return QVariant::fromValue(qmlAttachedPropertiesObject(
                d()->object, type.attachedPropertiesFunction(engine()->typeLoader())));
    }
 
    QQmlEnginePrivate *e = QQmlEnginePrivate::get(engine()->qmlEngine());
    if (type.isQJSValueSingleton())
        return QVariant::fromValue<QJSValue>(e->singletonInstance<QJSValue>(type));
 
    return QVariant::fromValue<QObject*>(e->singletonInstance<QObject*>(type));
}
 
ReturnedValue QQmlTypeWrapper::method_hasInstance(
        const FunctionObject *, const Value *thisObject, const Value *argv, int argc)
{
    // we want to immediately call instanceOf rather than going through Function
 
    if (!argc)
        return Encode(false);
    if (const Object *o = thisObject->as<Object>())
        return o->instanceOf(argv[0]);
    return Encode(false);
}
 
ReturnedValue QQmlTypeWrapper::method_toString(
        const FunctionObject *b, const Value *thisObject, const Value *, int)
{
    const QQmlTypeWrapper *typeWrapper = thisObject->as<QQmlTypeWrapper>();
    if (!typeWrapper)
        RETURN_UNDEFINED();
 
    const QString name = typeWrapper->d()->type().qmlTypeName();
    return Encode(b->engine()->newString(name.isEmpty()
            ? QLatin1String("Unknown Type")
            : name));
}
 
void QQmlTypeWrapper::initProto(ExecutionEngine *v4)
{
    if (v4->typeWrapperPrototype()->d_unchecked())
        return;
 
    Scope scope(v4);
    ScopedObject o(scope, v4->newObject());
 
    o->defineDefaultProperty(v4->symbol_hasInstance(), method_hasInstance, 1, Attr_ReadOnly);
    o->defineDefaultProperty(v4->id_toString(), method_toString, 0);
    o->setPrototypeOf(v4->functionPrototype());
 
    v4->jsObjects[QV4::ExecutionEngine::TypeWrapperProto] = o->d();
}
 
// Returns a type wrapper for type t on o.  This allows access of enums, and attached properties.
ReturnedValue QQmlTypeWrapper::create(QV4::ExecutionEngine *engine, QObject *o, const QQmlType &t,
                                     Heap::QQmlTypeWrapper::TypeNameMode mode)
{
    Q_ASSERT(t.isValid());
    initProto(engine);
 
    QV4::MemoryManager *mm = engine->memoryManager;
 
    if (const QMetaObject *mo = t.metaObject(); !mo || mo->constructorCount() == 0)
        return mm->allocate<QQmlTypeWrapper>(mode, o, t.priv())->asReturnedValue();
 
    return mm->allocate<QQmlTypeConstructor>(mode, o, t.priv())->asReturnedValue();
}
 
// Returns a type wrapper for importNamespace (of t) on o.  This allows nested resolution of a type in a
// namespace.
ReturnedValue QQmlTypeWrapper::create(
        QV4::ExecutionEngine *engine, QObject *o, const QQmlRefPointer<QQmlTypeNameCache> &t,
        const QQmlImportRef *importNamespace, Heap::QQmlTypeWrapper::TypeNameMode mode)
{
    Q_ASSERT(t);
    Q_ASSERT(importNamespace);
    initProto(engine);
 
    Scope scope(engine);
 
    Scoped<QQmlTypeWrapper> w(scope, engine->memoryManager->allocate<QQmlTypeWrapper>(
                                             mode, o, t.data(), importNamespace));
    return w.asReturnedValue();
}
 
static int enumForSingleton(QQmlTypeLoader *typeLoader, String *name, const QQmlType &type, bool *ok)
{
    Q_ASSERT(ok != nullptr);
    const int value = type.enumValue(typeLoader, name, ok);
    return *ok ? value : -1;
}
 
static ReturnedValue createEnumWrapper(ExecutionEngine *v4, Scope &scope, QQmlType type,
                                       int enumIndex, bool scoped)
{
    Scoped<QQmlEnumWrapper> enumWrapper(scope, v4->memoryManager->allocate<QQmlEnumWrapper>());
    enumWrapper->d()->typePrivate = type.priv();
    QQmlType::refHandle(enumWrapper->d()->typePrivate);
    enumWrapper->d()->enumIndex = enumIndex;
    enumWrapper->d()->scoped = scoped;
    return enumWrapper.asReturnedValue();
}
 
ReturnedValue QQmlTypeWrapper::virtualGet(const Managed *m, PropertyKey id, const Value *receiver, bool *hasProperty)
{
    // Keep this code in sync with ::virtualResolveLookupGetter
    Q_ASSERT(m->as<QQmlTypeWrapper>());
 
    if (!id.isString())
        return Object::virtualGet(m, id, receiver, hasProperty);
 
    QV4::ExecutionEngine *v4 = m->engine();
    QV4::Scope scope(v4);
    ScopedString name(scope, id.asStringOrSymbol());
 
    Scoped<QQmlTypeWrapper> w(scope, static_cast<const QQmlTypeWrapper *>(m));
 
    if (hasProperty)
        *hasProperty = true;
 
    QQmlRefPointer<QQmlContextData> context = v4->callingQmlContext();
 
    QObject *object = w->d()->object;
    QQmlType type = w->d()->type();
 
    QQmlEnginePrivate *enginePrivate = QQmlEnginePrivate::get(v4->qmlEngine());
    if (type.isValid()) {
 
        // singleton types are handled differently to other types.
        if (type.isSingleton()) {
 
            if (type.isQObjectSingleton() || type.isCompositeSingleton()) {
                if (QObject *qobjectSingleton = enginePrivate->singletonInstance<QObject*>(type)) {
                    // check for enum value
                    const bool includeEnums
                            = w->d()->typeNameMode() == Heap::QQmlTypeWrapper::IncludeEnums;
                    if (includeEnums && name->startsWithUpper()) {
                        bool ok = false;
                        int value = enumForSingleton(v4->typeLoader(), name, type, &ok);
                        if (ok)
                            return QV4::Value::fromInt32(value).asReturnedValue();
 
                        value = type.scopedEnumIndex(v4->typeLoader(), name, &ok);
                        if (ok)
                            return createEnumWrapper(v4, scope, type, value, true);
 
                        value = type.unscopedEnumIndex(v4->typeLoader(), name, &ok);
                        if (ok)
                            return createEnumWrapper(v4, scope, type, value, false);
                    }
 
                    // check for property.
                    bool ok;
                    const ReturnedValue result = QV4::QObjectWrapper::getQmlProperty(
                                v4, context, w->d(), qobjectSingleton, name,
                                QV4::QObjectWrapper::AttachMethods, &ok);
                    if (hasProperty)
                        *hasProperty = ok;
 
                    return result;
                }
            } else if (type.isQJSValueSingleton()) {
                QJSValue scriptSingleton = enginePrivate->singletonInstance<QJSValue>(type);
                if (!scriptSingleton.isUndefined()) {
                    // NOTE: if used in a binding, changes will not trigger re-evaluation since non-bindable.
                    QV4::ScopedObject o(scope, QJSValuePrivate::asReturnedValue(&scriptSingleton));
                    if (!!o)
                        return o->get(name);
                }
            }
 
            // Fall through to base implementation
 
        } else {
 
            if (name->startsWithUpper()) {
                bool ok = false;
                int value = type.enumValue(v4->typeLoader(), name, &ok);
                if (ok)
                    return QV4::Value::fromInt32(value).asReturnedValue();
 
                value = type.scopedEnumIndex(v4->typeLoader(), name, &ok);
                if (ok)
                    return createEnumWrapper(v4, scope, type, value, true);
 
                value = type.unscopedEnumIndex(v4->typeLoader(), name, &ok);
                if (ok)
                    return createEnumWrapper(v4, scope, type, value, false);
 
                // Fall through to base implementation
 
            } else if (w->d()->object) {
                QObject *ao = qmlAttachedPropertiesObject(
                        object, type.attachedPropertiesFunction(v4->typeLoader()));
                if (ao)
                    return QV4::QObjectWrapper::getQmlProperty(
                                v4, context, w->d(), ao, name, QV4::QObjectWrapper::AttachMethods,
                                hasProperty);
 
                // Fall through to base implementation
            }
 
            // Fall through to base implementation
        }
 
        // Fall through to base implementation
 
    } else if (w->d()->kind() == Heap::QQmlTypeWrapper::Namespace) {
        const QQmlTypeNameCache::Result r = w->d()->queryNamespace(name, v4);
        if (r.isValid()) {
            if (r.type.isValid()) {
                return create(scope.engine, object, r.type, w->d()->typeNameMode());
            } else if (r.scriptIndex != -1) {
                QV4::ScopedObject scripts(scope, context->importedScripts());
                return scripts->get(r.scriptIndex);
            } else if (r.importNamespace) {
                return create(scope.engine, object, context->imports(), r.importNamespace);
            }
 
            return QV4::Encode::undefined();
 
        }
 
        // Fall through to base implementation
 
    } else {
        Q_ASSERT(!"Unreachable");
    }
 
    bool ok = false;
    const ReturnedValue result = Object::virtualGet(m, id, receiver, &ok);
    if (hasProperty)
        *hasProperty = ok;
 
    return result;
}
 
 
bool QQmlTypeWrapper::virtualPut(Managed *m, PropertyKey id, const Value &value, Value *receiver)
{
    if (!id.isString())
        return Object::virtualPut(m, id, value, receiver);
 
 
    Q_ASSERT(m->as<QQmlTypeWrapper>());
    QQmlTypeWrapper *w = static_cast<QQmlTypeWrapper *>(m);
    QV4::Scope scope(w);
    if (scope.hasException())
        return false;
 
    ScopedString name(scope, id.asStringOrSymbol());
    QQmlRefPointer<QQmlContextData> context = scope.engine->callingQmlContext();
 
    QQmlType type = w->d()->type();
    if (type.isValid() && !type.isSingleton() && w->d()->object) {
        QObject *object = w->d()->object;
        QObject *ao = qmlAttachedPropertiesObject(
                object, type.attachedPropertiesFunction(scope.engine->typeLoader()));
        if (ao)
            return QV4::QObjectWrapper::setQmlProperty(
                        scope.engine, context, ao, name, QV4::QObjectWrapper::NoFlag, value);
        return false;
    } else if (type.isSingleton()) {
        QQmlEnginePrivate *e = QQmlEnginePrivate::get(scope.engine->qmlEngine());
        if (type.isQObjectSingleton() || type.isCompositeSingleton()) {
            if (QObject *qobjectSingleton = e->singletonInstance<QObject*>(type))
                return QV4::QObjectWrapper::setQmlProperty(
                            scope.engine, context, qobjectSingleton, name,
                            QV4::QObjectWrapper::NoFlag, value);
 
        } else {
            QJSValue scriptSingleton = e->singletonInstance<QJSValue>(type);
            if (!scriptSingleton.isUndefined()) {
                QV4::ScopedObject apiprivate(scope, QJSValuePrivate::asReturnedValue(&scriptSingleton));
                if (!apiprivate) {
                    QString error = QLatin1String("Cannot assign to read-only property \"") + name->toQString() + QLatin1Char('\"');
                    scope.engine->throwError(error);
                    return false;
                } else {
                    return apiprivate->put(name, value);
                }
            }
        }
    }
 
    return false;
}
 
PropertyAttributes QQmlTypeWrapper::virtualGetOwnProperty(const Managed *m, PropertyKey id, Property *p)
{
    if (id.isString()) {
        Scope scope(m);
        ScopedString n(scope, id.asStringOrSymbol());
        // ### Implement more efficiently.
        bool hasProperty = false;
        static_cast<const Object *>(m)->get(n, &hasProperty);
        return hasProperty ? Attr_Data : Attr_Invalid;
    }
 
    return QV4::Object::virtualGetOwnProperty(m, id, p);
}
 
bool QQmlTypeWrapper::virtualIsEqualTo(Managed *a, Managed *b)
{
    Q_ASSERT(a->as<QV4::QQmlTypeWrapper>());
    QV4::QQmlTypeWrapper *qmlTypeWrapperA = static_cast<QV4::QQmlTypeWrapper *>(a);
    if (QV4::QQmlTypeWrapper *qmlTypeWrapperB = b->as<QV4::QQmlTypeWrapper>())
        return qmlTypeWrapperA->toVariant() == qmlTypeWrapperB->toVariant();
    else if (QV4::QObjectWrapper *qobjectWrapper = b->as<QV4::QObjectWrapper>())
        return qmlTypeWrapperA->toVariant().value<QObject*>() == qobjectWrapper->object();
 
    return false;
}
 
static bool instanceHasCompilationUnit(QObject *wrapperObject)
{
    // If the target type is a composite type, we can cut instanceof short
    // if the object is not of a composite type (e.g. Rectangle{} is never
    // an instance of CustomRectangle)
 
    QQmlData *theirDData = QQmlData::get(wrapperObject);
    Q_ASSERT(theirDData); // must exist, otherwise how do we have a QObjectWrapper for it?!
    return !theirDData->compilationUnit.isNull();
}
 
static ReturnedValue instanceOfQObject(
        const QV4::QQmlTypeWrapper *typeWrapper, QObject *wrapperObject)
{
    QV4::ExecutionEngine *engine = typeWrapper->internalClass()->engine;
    // in case the wrapper outlived the QObject*
    if (!wrapperObject)
        return engine->throwTypeError();
 
    const QQmlType type = typeWrapper->d()->type();
    QQmlMetaObject myQmlType;
    if (type.isComposite()) {
        if (!instanceHasCompilationUnit(wrapperObject))
            return Encode(false);
 
        const CompiledData::CompilationUnit *cu
                = engine->typeLoader()->getType(type.sourceUrl())->compilationUnit();
 
        // If the CU isn't there, the type probably has errors, so we could not compile it.
        if (!cu)
            return Encode(false);
 
        myQmlType = QQmlMetaObject(cu->rootPropertyCache());
        Q_ASSERT(!myQmlType.isNull());
    } else if (type.isInlineComponentType()) {
        if (!instanceHasCompilationUnit(wrapperObject))
            return Encode(false);
 
        auto baseUrl = type.sourceUrl();
        baseUrl.setFragment(QString());
 
        const CompiledData::CompilationUnit *cu
                = engine->typeLoader()->getType(baseUrl)->compilationUnit();
 
        if (!cu)
            return Encode(false);
 
        myQmlType = QQmlMetaObject(cu->propertyCaches.at(
                cu->inlineComponentId(type.elementName())));
        Q_ASSERT(!myQmlType.isNull());
    } else {
        myQmlType = QQmlMetaType::metaObjectForType(type.typeId());
        if (myQmlType.isNull())
            return Encode(false);
    }
 
    const QMetaObject *theirType = wrapperObject->metaObject();
 
    if (QQmlMetaObject::canConvert(theirType, myQmlType))
        return Encode(true);
    else if (type.isValueType())
        return Encode::undefined();
    else
        return Encode(false);
}
 
ReturnedValue QQmlTypeWrapper::virtualInstanceOf(const Object *typeObject, const Value &var)
{
    Q_ASSERT(typeObject->as<QV4::QQmlTypeWrapper>());
    const QV4::QQmlTypeWrapper *typeWrapper = static_cast<const QV4::QQmlTypeWrapper *>(typeObject);
 
    if (const QObjectWrapper *objectWrapper = var.as<QObjectWrapper>())
        return instanceOfQObject(typeWrapper, objectWrapper->object());
 
    if (const QQmlTypeWrapper *varTypeWrapper = var.as<QQmlTypeWrapper>()) {
        // Singleton or attachment
        if (QObject *varObject = varTypeWrapper->object())
            return instanceOfQObject(typeWrapper, varObject);
    }
 
    const QQmlType type = typeWrapper->d()->type();
 
    // If the target type is an object type  we want null.
    if (!type.isValueType())
        return Encode(false);
 
    const auto canCastValueType = [&]() -> bool {
        if (const QQmlValueTypeWrapper *valueWrapper = var.as<QQmlValueTypeWrapper>()) {
            return QQmlMetaObject::canConvert(
                    valueWrapper->metaObject(), type.metaObjectForValueType());
        }
 
        const QMetaType typeId = type.typeId();
        if (const VariantObject *variantObject = var.as<VariantObject>()) {
            if (variantObject->d()->data().metaType() == typeId)
                return true;
        }
 
        switch (typeId.id()) {
        case QMetaType::Void:
            return var.isUndefined();
        case QMetaType::QVariant:
            return true; // Everything is a var
        case QMetaType::Int:
            return var.isInteger();
        case QMetaType::Double:
            return var.isDouble(); // Integers are also doubles
        case QMetaType::QString:
            return var.isString();
        case QMetaType::Bool:
            return var.isBoolean();
        case QMetaType::QUrl:
            if (var.as<UrlObject>())
                return true;
            break;
        case QMetaType::QDate:
        case QMetaType::QTime:
        case QMetaType::QDateTime:
            if (var.as<DateObject>())
                return true;
            break;
        default:
            break;
        }
 
        return false;
    };
 
    // We want "foo as valuetype" to return undefined if it doesn't match.
    return canCastValueType() ? Encode(true) : Encode::undefined();
}
 
ReturnedValue QQmlTypeWrapper::virtualResolveLookupGetter(const Object *object, ExecutionEngine *engine, Lookup *lookup)
{
    // Keep this code in sync with ::virtualGet
    PropertyKey id = engine->identifierTable->asPropertyKey(engine->currentStackFrame->v4Function->compilationUnit->runtimeStrings[lookup->nameIndex]);
    if (!id.isString())
        return Object::virtualResolveLookupGetter(object, engine, lookup);
    Scope scope(engine);
 
    const QQmlTypeWrapper *This = static_cast<const QQmlTypeWrapper *>(object);
    ScopedString name(scope, id.asStringOrSymbol());
    QQmlRefPointer<QQmlContextData> qmlContext = engine->callingQmlContext();
 
    Scoped<QQmlTypeWrapper> w(scope, static_cast<const QQmlTypeWrapper *>(This));
    QQmlType type = w->d()->type();
 
    if (type.isValid()) {
 
        if (type.isSingleton()) {
            QQmlEnginePrivate *e = QQmlEnginePrivate::get(engine->qmlEngine());
            if (type.isQObjectSingleton() || type.isCompositeSingleton()) {
                if (QObject *qobjectSingleton = e->singletonInstance<QObject*>(type)) {
                    const bool includeEnums
                            = w->d()->typeNameMode() == Heap::QQmlTypeWrapper::IncludeEnums;
                    if (!includeEnums || !name->startsWithUpper()) {
                        QQmlData *ddata = QQmlData::get(qobjectSingleton, false);
                        if (ddata && ddata->propertyCache) {
                            const QQmlPropertyData *property = ddata->propertyCache->property(name.getPointer(), qobjectSingleton, qmlContext);
                            if (property) {
                                ScopedValue val(scope, Value::fromReturnedValue(QV4::QObjectWrapper::wrap(engine, qobjectSingleton)));
                                if (qualifiesForMethodLookup(property)) {
                                    QV4::Heap::QObjectMethod *method = nullptr;
                                    setupQObjectMethodLookup(
                                            lookup, ddata->propertyCache, property,
                                            val->objectValue(), method);
                                    lookup->call = QV4::Lookup::Call::GetterSingletonMethod;
                                } else {
                                    setupQObjectLookup(
                                                lookup, ddata, property, val->objectValue(), This);
                                    lookup->call = QV4::Lookup::Call::GetterSingletonProperty;
                                }
                                return lookup->getter(engine, *object);
                            }
                            // Fall through to base implementation
                        }
                        // Fall through to base implementation
                    }
                    // Fall through to base implementation
                }
                // Fall through to base implementation
            }
            // Fall through to base implementation
        }
 
        if (name->startsWithUpper()) {
            bool ok = false;
            QQmlTypeLoader *typeLoader = engine->typeLoader();
            int value = type.enumValue(typeLoader, name, &ok);
            if (ok) {
                lookup->qmlEnumValueLookup.ic.set(engine, This->internalClass());
                lookup->qmlEnumValueLookup.encodedEnumValue
                        = QV4::Value::fromInt32(value).asReturnedValue();
                lookup->call = QV4::Lookup::Call::GetterEnumValue;
                return lookup->getter(engine, *object);
            }
 
            value = type.scopedEnumIndex(typeLoader, name, &ok);
            if (ok) {
                Scoped<QQmlEnumWrapper> enumWrapper(
                        scope, createEnumWrapper(engine, scope, type, value, true));
                auto *wrapper = enumWrapper->as<QQmlEnumWrapper>();
                lookup->qmlEnumWrapperLookup.ic.set(engine, This->internalClass());
                lookup->qmlEnumWrapperLookup.qmlEnumWrapper.set(engine, wrapper->heapObject());
                lookup->call = QV4::Lookup::Call::GetterEnum;
                return enumWrapper.asReturnedValue();
            }
 
            value = type.unscopedEnumIndex(typeLoader, name, &ok);
            if (ok) {
                Scoped<QQmlEnumWrapper> enumWrapper(
                        scope, createEnumWrapper(engine, scope, type, value, false));
                auto *wrapper = enumWrapper->as<QQmlEnumWrapper>();
                lookup->qmlEnumWrapperLookup.ic.set(engine, This->internalClass());
                lookup->qmlEnumWrapperLookup.qmlEnumWrapper.set(engine, wrapper->heapObject());
                lookup->call = QV4::Lookup::Call::GetterEnum;
                return enumWrapper.asReturnedValue();
            }
 
            // Fall through to base implementation
        } else if (w->d()->object) {
            QObject *ao = qmlAttachedPropertiesObject(
                    w->d()->object, type.attachedPropertiesFunction(engine->typeLoader()));
            if (ao) {
                // ### QTBUG-126877: Optimize this case
                lookup->call = QV4::Lookup::Call::GetterQObjectPropertyFallback;
                return lookup->getter(engine, *object);
            }
        }
        // Fall through to base implementation
    }
    /* ### QTBUG-126877: use QV4::Object::virtualResolveLookupGetter once we can be sure
       that we don't run into issues related to Function being our prototype  */
    lookup->call = QV4::Lookup::Call::GetterQObjectPropertyFallback;
    return lookup->getter(engine, *object);
}
 
bool QQmlTypeWrapper::virtualResolveLookupSetter(Object *object, ExecutionEngine *engine, Lookup *lookup, const Value &value)
{
    return Object::virtualResolveLookupSetter(object, engine, lookup, value);
}
 
OwnPropertyKeyIterator *QQmlTypeWrapper::virtualOwnPropertyKeys(const Object *m, Value *target)
{
    QV4::Scope scope(m->engine());
    QV4::Scoped<QQmlTypeWrapper> typeWrapper(scope, m);
    Q_ASSERT(typeWrapper);
    if (QObject *object = typeWrapper->object()) {
        QV4::Scoped<QV4::QObjectWrapper> objectWrapper(scope, QV4::QObjectWrapper::wrap(typeWrapper->engine(), object));
        return QV4::QObjectWrapper::virtualOwnPropertyKeys(objectWrapper, target);
    }
 
    return Object::virtualOwnPropertyKeys(m, target);
}
 
int QQmlTypeWrapper::virtualMetacall(Object *object, QMetaObject::Call call, int index, void **a)
{
    QQmlTypeWrapper *wrapper = object->as<QQmlTypeWrapper>();
    Q_ASSERT(wrapper);
 
    if (QObject *qObject = wrapper->object())
        return QMetaObject::metacall(qObject, call, index, a);
 
    return 0;
}
 
ReturnedValue QQmlTypeWrapper::lookupSingletonProperty(Lookup *l, ExecutionEngine *engine, const Value &object)
{
    const auto revertLookup = [l, engine, &object]() {
        l->qobjectLookup.propertyCache->release();
        l->qobjectLookup.propertyCache = nullptr;
        l->call = QV4::Lookup::Call::GetterGeneric;
        return Lookup::getterGeneric(l, engine, object);
    };
 
    // we can safely cast to a QV4::Object here. If object is something else,
    // the internal class won't match
    Heap::Object *o = static_cast<Heap::Object *>(object.heapObject());
 
    // The qmlTypeIc check is not strictly necessary.
    // If we have different ways to get to the same QObject type
    // we can use the same lookup to get its properties, no matter
    // how we've found the object. Most of the few times this check
    // fails, we will, of course have different object types. So
    // this check provides an early exit for the error case.
    //
    // So, if we ever need more bits in qobjectLookup, qmlTypeIc is the
    // member to be replaced.
    if (!o || o->internalClass != l->qobjectLookup.qmlTypeIc)
        return revertLookup();
 
    Heap::QQmlTypeWrapper *This = static_cast<Heap::QQmlTypeWrapper *>(o);
 
    QQmlType type = This->type();
    if (!type.isValid())
        return revertLookup();
 
    if (!type.isQObjectSingleton() && !type.isCompositeSingleton())
        return revertLookup();
 
    QQmlEnginePrivate *e = QQmlEnginePrivate::get(engine->qmlEngine());
    QObject *qobjectSingleton = e->singletonInstance<QObject *>(type);
    Q_ASSERT(qobjectSingleton);
 
    Scope scope(engine);
    ScopedValue obj(scope, QV4::QObjectWrapper::wrap(engine, qobjectSingleton));
    const QObjectWrapper::Flags flags = l->forCall
            ? QObjectWrapper::AllowOverride
            : (QObjectWrapper::AttachMethods | QObjectWrapper::AllowOverride);
    return QObjectWrapper::lookupPropertyGetterImpl(l, engine, obj, flags, revertLookup);
}
 
ReturnedValue QQmlTypeWrapper::lookupSingletonMethod(Lookup *l, ExecutionEngine *engine, const Value &object)
{
    const auto revertLookup = [l, engine, &object]() {
        l->qobjectMethodLookup.propertyCache->release();
        l->qobjectMethodLookup.propertyCache = nullptr;
        l->call = QV4::Lookup::Call::GetterGeneric;
        return Lookup::getterGeneric(l, engine, object);
    };
 
    // We cannot safely cast here as we don't explicitly check the IC. Therefore as().
    const QQmlTypeWrapper *This = object.as<QQmlTypeWrapper>();
    if (!This)
        return revertLookup();
 
    QQmlType type = This->d()->type();
    if (!type.isValid())
        return revertLookup();
 
    if (!type.isQObjectSingleton() && !type.isCompositeSingleton())
        return revertLookup();
 
    QQmlEnginePrivate *e = QQmlEnginePrivate::get(engine->qmlEngine());
    QObject *qobjectSingleton = e->singletonInstance<QObject *>(type);
    Q_ASSERT(qobjectSingleton);
 
    Scope scope(engine);
    ScopedValue obj(scope, QV4::QObjectWrapper::wrap(engine, qobjectSingleton));
    return QObjectWrapper::lookupMethodGetterImpl(
                l, engine, obj, l->forCall ? QObjectWrapper::NoFlag : QObjectWrapper::AttachMethods,
                revertLookup);
}
 
ReturnedValue QQmlTypeWrapper::lookupEnumValue(Lookup *l, ExecutionEngine *engine, const Value &base)
{
    auto *o = static_cast<Heap::Object *>(base.heapObject());
    if (!o || o->internalClass != l->qmlEnumValueLookup.ic) {
        l->call = QV4::Lookup::Call::GetterGeneric;
        return Lookup::getterGeneric(l, engine, base);
    }
 
    return l->qmlEnumValueLookup.encodedEnumValue;
}
 
ReturnedValue QQmlTypeWrapper::lookupEnum(Lookup *l, ExecutionEngine *engine, const Value &base)
{
    Scope scope(engine);
    Scoped<QQmlEnumWrapper> enumWrapper(scope, l->qmlEnumWrapperLookup.qmlEnumWrapper.get());
 
    auto *o = static_cast<Heap::Object *>(base.heapObject());
    if (!o || o->internalClass != l->qmlEnumWrapperLookup.ic) {
        QQmlType::derefHandle(enumWrapper->d()->typePrivate);
        l->qmlEnumWrapperLookup.qmlEnumWrapper.clear();
        l->call = QV4::Lookup::Call::GetterGeneric;
        return Lookup::getterGeneric(l, engine, base);
    }
 
    return enumWrapper.asReturnedValue();
}
 
void Heap::QQmlEnumWrapper::destroy()
{
    QQmlType::derefHandle(typePrivate);
    typePrivate = nullptr;
    Object::destroy();
}
 
QQmlType Heap::QQmlEnumWrapper::type() const
{
    return QQmlType(typePrivate);
}
 
ReturnedValue QQmlEnumWrapper::virtualGet(const Managed *m, PropertyKey id, const Value *receiver,
                                          bool *hasProperty)
{
    Q_ASSERT(m->as<QQmlEnumWrapper>());
    if (!id.isString())
        return Object::virtualGet(m, id, receiver, hasProperty);
 
    const QQmlEnumWrapper *resource = static_cast<const QQmlEnumWrapper *>(m);
    QV4::ExecutionEngine *v4 = resource->engine();
    QV4::Scope scope(v4);
    ScopedString name(scope, id.asStringOrSymbol());
 
    QQmlType type = resource->d()->type();
    int index = resource->d()->enumIndex;
 
    bool ok = false;
    auto *typeLoader = v4->typeLoader();
    int value = resource->d()->scoped ? type.scopedEnumValue(typeLoader, index, name, &ok)
                                      : type.unscopedEnumValue(typeLoader, index, name, &ok);
    if (hasProperty)
        *hasProperty = ok;
    if (ok)
        return QV4::Value::fromInt32(value).asReturnedValue();
 
    return Object::virtualGet(m, id, receiver, hasProperty);
}
 
QT_END_NAMESPACE