Remove most uses of Value from qml/qml

Change-Id: I409a8505a9e01f86d777bc694d24516d1c8f0c4d
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>

21 files changed, 153 insertions, 136 deletions

diff --git a/src/qml/jsruntime/qv4qobjectwrapper.cpp b/src/qml/jsruntime/qv4qobjectwrapper.cpp
index d28514f0c8..53e915c1a4 100644
--- a/src/qml/jsruntime/qv4qobjectwrapper.cpp
+++ b/src/qml/jsruntime/qv4qobjectwrapper.cpp
@@ -473,7 +473,7 @@ bool QObjectWrapper::setQmlProperty(ExecutionContext *ctx, QQmlContextData *qmlC
         // allow assignment of "special" values (null, undefined, function) to var properties
         QQmlVMEMetaObject *vmemo = QQmlVMEMetaObject::get(object);
         Q_ASSERT(vmemo);
-        vmemo->setVMEProperty(result->coreIndex, *value);
+        vmemo->setVMEProperty(result->coreIndex, value);
         return true;
     }
 
@@ -517,7 +517,7 @@ bool QObjectWrapper::setQmlProperty(ExecutionContext *ctx, QQmlContextData *qmlC
     } else if (result->isVarProperty()) {
         QQmlVMEMetaObject *vmemo = QQmlVMEMetaObject::get(object);
         Q_ASSERT(vmemo);
-        vmemo->setVMEProperty(result->coreIndex, *value);
+        vmemo->setVMEProperty(result->coreIndex, value);
     } else {
         QVariant v;
         if (result->isQList())
diff --git a/src/qml/jsruntime/qv4scopedvalue_p.h b/src/qml/jsruntime/qv4scopedvalue_p.h
index b32aed12d9..3a7526197e 100644
--- a/src/qml/jsruntime/qv4scopedvalue_p.h
+++ b/src/qml/jsruntime/qv4scopedvalue_p.h
@@ -370,6 +370,8 @@ struct ScopedCallData {
         ptr->argc = argc;
 #ifndef QT_NO_DEBUG
         scope.size += size;
+        for (int ii = 0; ii < qMax(argc, (int)QV4::Global::ReservedArgumentCount); ++ii)
+            ptr->args[ii] = QV4::Primitive::undefinedValue();
 #endif
     }
 
diff --git a/src/qml/qml/qqmlboundsignal.cpp b/src/qml/qml/qqmlboundsignal.cpp
index 76825edd94..11dc873dd4 100644
--- a/src/qml/qml/qqmlboundsignal.cpp
+++ b/src/qml/qml/qqmlboundsignal.cpp
@@ -199,35 +199,31 @@ void QQmlBoundSignalExpression::evaluate(void **a)
         int *argsTypes = QQmlPropertyCache::methodParameterTypes(m_target, methodIndex, dummy, 0);
         int argCount = argsTypes ? *argsTypes : 0;
 
-        QV4::Value *args = (QV4::Value *)alloca(qMax(argCount, (int)QV4::Global::ReservedArgumentCount)*sizeof(QV4::Value));
-#ifndef QT_NO_DEBUG
-        for (int ii = 0; ii < qMax(argCount, (int)QV4::Global::ReservedArgumentCount); ++ii)
-            args[ii] = QV4::Primitive::undefinedValue();
-#endif
+        QV4::ScopedValue f(scope, m_v8function.value());
+        QV4::ScopedCallData callData(scope, argCount);
         for (int ii = 0; ii < argCount; ++ii) {
             int type = argsTypes[ii + 1];
             //### ideally we would use metaTypeToJS, however it currently gives different results
             //    for several cases (such as QVariant type and QObject-derived types)
             //args[ii] = engine->metaTypeToJS(type, a[ii + 1]);
             if (type == QMetaType::QVariant) {
-                args[ii] = QV4::Value::fromReturnedValue(engine->fromVariant(*((QVariant *)a[ii + 1])));
+                callData->args[ii] = engine->fromVariant(*((QVariant *)a[ii + 1]));
             } else if (type == QMetaType::Int) {
                 //### optimization. Can go away if we switch to metaTypeToJS, or be expanded otherwise
-                args[ii] = QV4::Primitive::fromInt32(*reinterpret_cast<const int*>(a[ii + 1]));
+                callData->args[ii] = QV4::Primitive::fromInt32(*reinterpret_cast<const int*>(a[ii + 1]));
             } else if (type == qMetaTypeId<QQmlV4Handle>()) {
-                args[ii] = QV4::Value::fromReturnedValue(*reinterpret_cast<QQmlV4Handle *>(a[ii + 1]));
+                callData->args[ii] = *reinterpret_cast<QQmlV4Handle *>(a[ii + 1]);
             } else if (ep->isQObject(type)) {
                 if (!*reinterpret_cast<void* const *>(a[ii + 1]))
-                    args[ii] = QV4::Primitive::nullValue();
+                    callData->args[ii] = QV4::Primitive::nullValue();
                 else
-                    args[ii] = QV4::Value::fromReturnedValue(QV4::QObjectWrapper::wrap(ep->v4engine(), *reinterpret_cast<QObject* const *>(a[ii + 1])));
+                    callData->args[ii] = QV4::QObjectWrapper::wrap(ep->v4engine(), *reinterpret_cast<QObject* const *>(a[ii + 1]));
             } else {
-                args[ii] = QV4::Value::fromReturnedValue(engine->fromVariant(QVariant(type, a[ii + 1])));
+                callData->args[ii] = engine->fromVariant(QVariant(type, a[ii + 1]));
             }
         }
 
-        QV4::ScopedValue f(scope, m_v8function.value());
-        QQmlJavaScriptExpression::evaluate(context(), f, argCount, args, 0);
+        QQmlJavaScriptExpression::evaluate(context(), f, callData, 0);
     }
     ep->dereferenceScarceResources(); // "release" scarce resources if top-level expression evaluation is complete.
 }
diff --git a/src/qml/qml/qqmlcomponent.cpp b/src/qml/qml/qqmlcomponent.cpp
index 0b5e8cff0a..b83d901da5 100644
--- a/src/qml/qml/qqmlcomponent.cpp
+++ b/src/qml/qml/qqmlcomponent.cpp
@@ -1122,9 +1122,9 @@ public:
 
     QV8Engine *v8;
     QPointer<QObject> parent;
-    QV4::Value valuemap;
+    QV4::SafeValue valuemap;
     QV4::SafeValue qmlGlobal;
-    QV4::Value m_statusChanged;
+    QV4::SafeValue m_statusChanged;
 protected:
     virtual void statusChanged(Status);
     virtual void setInitialState(QObject *);
@@ -1385,7 +1385,7 @@ void QQmlComponent::incubateObject(QQmlV4Function *args)
 }
 
 // XXX used by QSGLoader
-void QQmlComponentPrivate::initializeObjectWithInitialProperties(const QV4::ValueRef qmlGlobal, const QV4::Value &valuemap, QObject *toCreate)
+void QQmlComponentPrivate::initializeObjectWithInitialProperties(const QV4::ValueRef qmlGlobal, const QV4::ValueRef valuemap, QObject *toCreate)
 {
     QQmlEnginePrivate *ep = QQmlEnginePrivate::get(engine);
     QV8Engine *v8engine = ep->v8engine();
@@ -1395,7 +1395,7 @@ void QQmlComponentPrivate::initializeObjectWithInitialProperties(const QV4::Valu
     QV4::ScopedValue object(scope, QV4::QObjectWrapper::wrap(v4engine, toCreate));
     Q_ASSERT(object->asObject());
 
-    if (!valuemap.isUndefined()) {
+    if (!valuemap->isUndefined()) {
         QQmlComponentExtension *e = componentExtension(v8engine);
         QV4::ScopedObject qmlGlobalObj(scope, qmlGlobal);
         QV4::Scoped<QV4::FunctionObject>  f(scope, QV4::Script::evaluate(QV8Engine::getV4(v8engine),
@@ -1503,7 +1503,7 @@ void QmlIncubatorObject::setInitialState(QObject *o)
         QV4::Scoped<QV4::FunctionObject> f(scope, QV4::Script::evaluate(v4, QString::fromLatin1(INITIALPROPERTIES_SOURCE), qmlGlobal));
         QV4::ScopedCallData callData(scope, 2);
         callData->thisObject = v4->globalObject;
-        callData->args[0] = QV4::Value::fromReturnedValue(QV4::QObjectWrapper::wrap(v4, o));
+        callData->args[0] = QV4::QObjectWrapper::wrap(v4, o);
         callData->args[1] = valuemap;
         f->call(callData);
     }
@@ -1533,11 +1533,10 @@ void QmlIncubatorObject::statusChanged(Status s)
         QQmlData::get(object())->indestructible = false;
     }
 
-    QV4::Value callback = m_statusChanged;
-
-    if (QV4::FunctionObject *f = callback.asFunctionObject()) {
-        QV4::ExecutionContext *ctx = f->engine()->current;
-        QV4::Scope scope(ctx);
+    QV4::Scope scope(QV8Engine::getV4(v8));
+    QV4::ScopedFunctionObject f(scope, m_statusChanged);
+    if (f) {
+        QV4::ExecutionContext *ctx = scope.engine->current;
         try {
             QV4::ScopedCallData callData(scope, 1);
             callData->thisObject = this;
diff --git a/src/qml/qml/qqmlcomponent_p.h b/src/qml/qml/qqmlcomponent_p.h
index f2f81c8ab2..d9a2427cd5 100644
--- a/src/qml/qml/qqmlcomponent_p.h
+++ b/src/qml/qml/qqmlcomponent_p.h
@@ -91,7 +91,7 @@ public:
 
     QObject *beginCreate(QQmlContextData *);
     void completeCreate();
-    void initializeObjectWithInitialProperties(const QV4::ValueRef qmlGlobal, const QV4::Value &valuemap, QObject *toCreate);
+    void initializeObjectWithInitialProperties(const QV4::ValueRef qmlGlobal, const QV4::ValueRef valuemap, QObject *toCreate);
 
     QQmlTypeData *typeData;
     virtual void typeDataReady(QQmlTypeData *);
diff --git a/src/qml/qml/qqmlcontextwrapper.cpp b/src/qml/qml/qqmlcontextwrapper.cpp
index 15974b07fa..c867b6e126 100644
--- a/src/qml/qml/qqmlcontextwrapper.cpp
+++ b/src/qml/qml/qqmlcontextwrapper.cpp
@@ -105,23 +105,26 @@ QQmlContextData *QmlContextWrapper::callingContext(ExecutionEngine *v4)
     return !!c ? c->getContext() : 0;
 }
 
-QQmlContextData *QmlContextWrapper::getContext(const Value &value)
+QQmlContextData *QmlContextWrapper::getContext(const ValueRef value)
 {
-    QV4::ExecutionEngine *v4 = value.engine();
+    QV4::ExecutionEngine *v4 = value->engine();
     if (!v4)
         return 0;
 
     Scope scope(v4);
-    QV4::Scoped<QmlContextWrapper> c(scope, value.as<QmlContextWrapper>());
+    QV4::Scoped<QmlContextWrapper> c(scope, value);
 
-    return !!c ? c->getContext():0;
+    return c ? c->getContext() : 0;
 }
 
-void QmlContextWrapper::takeContextOwnership(const Value &qmlglobal)
+void QmlContextWrapper::takeContextOwnership(const ValueRef qmlglobal)
 {
-    Object *o = qmlglobal.asObject();
-    QmlContextWrapper *c = o ? o->as<QmlContextWrapper>() : 0;
-    assert(c);
+    QV4::ExecutionEngine *v4 = qmlglobal->engine();
+    Q_ASSERT(v4);
+
+    Scope scope(v4);
+    QV4::Scoped<QmlContextWrapper> c(scope, qmlglobal);
+    Q_ASSERT(c);
     c->ownsContext = true;
 }
 
diff --git a/src/qml/qml/qqmlcontextwrapper_p.h b/src/qml/qml/qqmlcontextwrapper_p.h
index 6660e1ab29..86ad4e5616 100644
--- a/src/qml/qml/qqmlcontextwrapper_p.h
+++ b/src/qml/qml/qqmlcontextwrapper_p.h
@@ -74,11 +74,11 @@ struct Q_QML_EXPORT QmlContextWrapper : Object
     static ReturnedValue urlScope(QV8Engine *e, const QUrl &);
 
     static QQmlContextData *callingContext(ExecutionEngine *v4);
-    static void takeContextOwnership(const QV4::Value &qmlglobal);
+    static void takeContextOwnership(const ValueRef qmlglobal);
 
     inline QObject *getScopeObject() const { return scopeObject; }
     inline QQmlContextData *getContext() const { return context; }
-    static QQmlContextData *getContext(const Value &value);
+    static QQmlContextData *getContext(const ValueRef value);
 
     void setReadOnly(bool b) { readOnly = b; }
 
diff --git a/src/qml/qml/qqmljavascriptexpression.cpp b/src/qml/qml/qqmljavascriptexpression.cpp
index 788d3e241c..938b14a15f 100644
--- a/src/qml/qml/qqmljavascriptexpression.cpp
+++ b/src/qml/qml/qqmljavascriptexpression.cpp
@@ -123,22 +123,26 @@ void QQmlJavaScriptExpression::resetNotifyOnValueChanged()
 }
 
 QV4::ReturnedValue QQmlJavaScriptExpression::evaluate(QQmlContextData *context,
-                                   const QV4::Value &function, bool *isUndefined)
+                                   const QV4::ValueRef function, bool *isUndefined)
 {
-    return evaluate(context, function, 0, 0, isUndefined);
+    QV4::ExecutionEngine *v4 = QV8Engine::getV4(context->engine);
+    QV4::Scope scope(v4);
+    QV4::ScopedCallData callData(scope, 0);
+
+    return evaluate(context, function, callData, isUndefined);
 }
 
 QV4::ReturnedValue QQmlJavaScriptExpression::evaluate(QQmlContextData *context,
-                                   const QV4::Value &function,
-                                   int argc, QV4::Value *args,
+                                   const QV4::ValueRef function,
+                                   QV4::CallData *callData,
                                    bool *isUndefined)
 {
     Q_ASSERT(context && context->engine);
 
-    if (function.isUndefined()) {
+    if (function->isUndefined()) {
         if (isUndefined)
             *isUndefined = true;
-        return QV4::Primitive::undefinedValue().asReturnedValue();
+        return QV4::Encode::undefined();
     }
 
     QQmlEnginePrivate *ep = QQmlEnginePrivate::get(context->engine);
@@ -165,7 +169,6 @@ QV4::ReturnedValue QQmlJavaScriptExpression::evaluate(QQmlContextData *context,
     QV4::ScopedValue result(scope, QV4::Primitive::undefinedValue());
     QV4::ExecutionContext *ctx = v4->current;
     try {
-        QV4::ScopedCallData callData(scope, argc);
         callData->thisObject = ep->v8engine()->global();
         if (scopeObject() && requiresThisObject()) {
             QV4::ScopedValue value(scope, QV4::QObjectWrapper::wrap(ctx->engine, scopeObject()));
@@ -173,8 +176,7 @@ QV4::ReturnedValue QQmlJavaScriptExpression::evaluate(QQmlContextData *context,
                 callData->thisObject = value;
         }
 
-        memcpy(callData->args, args, argc*sizeof(QV4::Value));
-        result = function.asFunctionObject()->call(callData);
+        result = function->asFunctionObject()->call(callData);
 
         if (isUndefined)
             *isUndefined = result->isUndefined();
diff --git a/src/qml/qml/qqmljavascriptexpression_p.h b/src/qml/qml/qqmljavascriptexpression_p.h
index c13e191216..031cc2d2c1 100644
--- a/src/qml/qml/qqmljavascriptexpression_p.h
+++ b/src/qml/qml/qqmljavascriptexpression_p.h
@@ -110,11 +110,8 @@ public:
 
     QQmlJavaScriptExpression(VTable *vtable);
 
-    QV4::ReturnedValue evaluate(QQmlContextData *, const QV4::Value &function,
-                                  bool *isUndefined);
-    QV4::ReturnedValue evaluate(QQmlContextData *, const QV4::Value &function,
-                                  int argc, QV4::Value *args,
-                                  bool *isUndefined);
+    QV4::ReturnedValue evaluate(QQmlContextData *, const QV4::ValueRef function, bool *isUndefined);
+    QV4::ReturnedValue evaluate(QQmlContextData *, const QV4::ValueRef function, QV4::CallData *callData, bool *isUndefined);
 
     inline bool requiresThisObject() const;
     inline void setRequiresThisObject(bool v);
diff --git a/src/qml/qml/qqmllistwrapper.cpp b/src/qml/qml/qqmllistwrapper.cpp
index 3746d58d77..523b7cc5de 100644
--- a/src/qml/qml/qqmllistwrapper.cpp
+++ b/src/qml/qml/qqmllistwrapper.cpp
@@ -158,7 +158,7 @@ Property *QmlListWrapper::advanceIterator(Managed *m, ObjectIterator *it, String
             *attrs = QV4::Attr_Data;
         *index = it->arrayIndex;
         ++it->arrayIndex;
-        it->tmpDynamicProperty.value = QV4::Value::fromReturnedValue(QV4::QObjectWrapper::wrap(w->engine(), w->property.at(&w->property, *index)));
+        it->tmpDynamicProperty.value = QV4::QObjectWrapper::wrap(w->engine(), w->property.at(&w->property, *index));
         return &it->tmpDynamicProperty;
     }
     return QV4::Object::advanceIterator(m, it, name, index, attrs);
diff --git a/src/qml/qml/qqmllocale.cpp b/src/qml/qml/qqmllocale.cpp
index e79f1582d9..9c09960e93 100644
--- a/src/qml/qml/qqmllocale.cpp
+++ b/src/qml/qml/qqmllocale.cpp
@@ -116,9 +116,9 @@ DEFINE_MANAGED_VTABLE(QQmlLocaleData);
     if (!r) \
         V4THROW_ERROR("Not a valid Locale object")
 
-static bool isLocaleObject(const QV4::Value &val)
+static bool isLocaleObject(const QV4::ValueRef val)
 {
-    return val.as<QQmlLocaleData>();
+    return val->as<QQmlLocaleData>();
 }
 
 //--------------
diff --git a/src/qml/qml/qqmlobjectcreator.cpp b/src/qml/qml/qqmlobjectcreator.cpp
index 3ea40bd24c..65fc2a40d5 100644
--- a/src/qml/qml/qqmlobjectcreator.cpp
+++ b/src/qml/qml/qqmlobjectcreator.cpp
@@ -586,7 +586,7 @@ void QmlObjectCreator::setPropertyValue(QQmlPropertyData *property, const QV4::C
             QString stringValue = binding->valueAsString(&qmlUnit->header);
             if (property->isVarProperty()) {
                 QV4::ScopedString s(scope, v4->newString(stringValue));
-                _vmeMetaObject->setVMEProperty(property->coreIndex, s.asValue());
+                _vmeMetaObject->setVMEProperty(property->coreIndex, s);
             } else {
                 QVariant value = QQmlStringConverters::variantFromString(stringValue);
                 argv[0] = &value;
diff --git a/src/qml/qml/qqmlproperty.cpp b/src/qml/qml/qqmlproperty.cpp
index a0fd98483b..7723404831 100644
--- a/src/qml/qml/qqmlproperty.cpp
+++ b/src/qml/qml/qqmlproperty.cpp
@@ -1537,7 +1537,7 @@ bool QQmlPropertyPrivate::writeBinding(QObject *object,
 
         QQmlVMEMetaObject *vmemo = QQmlVMEMetaObject::get(object);
         Q_ASSERT(vmemo);
-        vmemo->setVMEProperty(core.coreIndex, *result);
+        vmemo->setVMEProperty(core.coreIndex, result);
     } else if (isUndefined && core.isResettable()) {
         void *args[] = { 0 };
         QMetaObject::metacall(object, QMetaObject::ResetProperty, core.coreIndex, args);
diff --git a/src/qml/qml/qqmlvme.cpp b/src/qml/qml/qqmlvme.cpp
index 512b9b4674..f256f3a1ce 100644
--- a/src/qml/qml/qqmlvme.cpp
+++ b/src/qml/qml/qqmlvme.cpp
@@ -296,12 +296,12 @@ static QVariant variantFromString(const QString &string)
 
 #define QML_STORE_VAR(name, value) \
     QML_BEGIN_INSTR(name) \
-        QV4::Value v4value = value; \
+        QV4::ValueRef valueref = value; \
         QObject *target = objects.top(); \
         CLEAN_PROPERTY(target, instr.propertyIndex); \
         QQmlVMEMetaObject *vmemo = QQmlVMEMetaObject::get(target); \
         Q_ASSERT(vmemo); \
-        vmemo->setVMEProperty(instr.propertyIndex, v4value); \
+        vmemo->setVMEProperty(instr.propertyIndex, valueref); \
     QML_END_INSTR(name)
 
 #define QML_STORE_POINTER(name, value) \
@@ -339,6 +339,9 @@ QObject *QQmlVME::run(QList<QQmlError> *errors,
 
     QQmlEngine *engine = states.at(0).context->engine;
     QQmlEnginePrivate *ep = QQmlEnginePrivate::get(engine);
+    QV4::ExecutionEngine *v4 = ep->v4engine();
+    QV4::Scope valueScope(v4);
+    QV4::ScopedValue tmpValue(valueScope);
 
     int status = -1; // needed for dbus
     QQmlPropertyPrivate::WriteFlags flags = QQmlPropertyPrivate::BypassInterceptor |
@@ -372,7 +375,7 @@ QObject *QQmlVME::run(QList<QQmlError> *errors,
         // Store a created object in a property.  These all pop from the objects stack.
         QML_STORE_VALUE(StoreObject, QObject *, objects.pop());
         QML_STORE_VALUE(StoreVariantObject, QVariant, QVariant::fromValue(objects.pop()));
-        QML_STORE_VAR(StoreVarObject, QV4::Value::fromReturnedValue(QV4::QObjectWrapper::wrap(ep->v4engine(), objects.pop())));
+        QML_STORE_VAR(StoreVarObject, (tmpValue = QV4::QObjectWrapper::wrap(ep->v4engine(), objects.pop())));
 
         // Store a literal value in a corresponding property
         QML_STORE_VALUE(StoreFloat, float, instr.value);
@@ -420,7 +423,7 @@ QObject *QQmlVME::run(QList<QQmlError> *errors,
 
         // Store a literal value in a var property.
         // We deliberately do not use string converters here
-        QML_STORE_VAR(StoreVar, QV4::Value::fromReturnedValue(ep->v8engine()->fromVariant(PRIMITIVES.at(instr.value))));
+        QML_STORE_VAR(StoreVar, (tmpValue = ep->v8engine()->fromVariant(PRIMITIVES.at(instr.value))));
         QML_STORE_VAR(StoreVarInteger, QV4::Primitive::fromInt32(instr.value));
         QML_STORE_VAR(StoreVarDouble, QV4::Primitive::fromDouble(instr.value));
         QML_STORE_VAR(StoreVarBool, QV4::Primitive::fromBoolean(instr.value));
diff --git a/src/qml/qml/qqmlvmemetaobject.cpp b/src/qml/qml/qqmlvmemetaobject.cpp
index e8960eb328..dfba6bb3b6 100644
--- a/src/qml/qml/qqmlvmemetaobject.cpp
+++ b/src/qml/qml/qqmlvmemetaobject.cpp
@@ -937,7 +937,7 @@ int QQmlVMEMetaObject::metaCall(QMetaObject::Call c, int _id, void **a)
                 callData->thisObject = ep->v8engine()->global();
 
                 for (int ii = 0; ii < data->parameterCount; ++ii)
-                    callData->args[ii] = QV4::Value::fromReturnedValue(ep->v8engine()->fromVariant(*(QVariant *)a[ii + 1]));
+                    callData->args[ii] = ep->v8engine()->fromVariant(*(QVariant *)a[ii + 1]);
 
                 QV4::ScopedValue result(scope);
                 QV4::ExecutionContext *ctx = function->engine()->current;
@@ -1023,7 +1023,7 @@ QVariant QQmlVMEMetaObject::readPropertyAsVariant(int id)
     }
 }
 
-void QQmlVMEMetaObject::writeVarProperty(int id, const QV4::Value &value)
+void QQmlVMEMetaObject::writeVarProperty(int id, const QV4::ValueRef value)
 {
     Q_ASSERT(id >= firstVarPropertyIndex);
     if (!ensureVarPropertiesAllocated())
@@ -1040,8 +1040,7 @@ void QQmlVMEMetaObject::writeVarProperty(int id, const QV4::Value &value)
     QObject *valueObject = 0;
     QQmlVMEVariantQObjectPtr *guard = getQObjectGuardForProperty(id);
 
-    QV4::ScopedValue v(scope, value);
-    QV4::ScopedObject o(scope, v);
+    QV4::ScopedObject o(scope, value);
     if (o) {
         // And, if the new value is a scarce resource, we need to ensure that it does not get
         // automatically released by the engine until no other references to it exist.
@@ -1064,7 +1063,7 @@ void QQmlVMEMetaObject::writeVarProperty(int id, const QV4::Value &value)
     }
 
     // Write the value and emit change signal as appropriate.
-    vp->putIndexed(id - firstVarPropertyIndex, v);
+    vp->putIndexed(id - firstVarPropertyIndex, value);
     activate(object, methodOffset() + id, 0);
 }
 
@@ -1202,7 +1201,7 @@ QV4::ReturnedValue QQmlVMEMetaObject::vmeProperty(int index)
     return readVarProperty(index - propOffset());
 }
 
-void QQmlVMEMetaObject::setVMEProperty(int index, const QV4::Value &v)
+void QQmlVMEMetaObject::setVMEProperty(int index, const QV4::ValueRef v)
 {
     if (index < propOffset()) {
         Q_ASSERT(parentVMEMetaObject());
diff --git a/src/qml/qml/qqmlvmemetaobject_p.h b/src/qml/qml/qqmlvmemetaobject_p.h
index c9babc0492..056139114c 100644
--- a/src/qml/qml/qqmlvmemetaobject_p.h
+++ b/src/qml/qml/qqmlvmemetaobject_p.h
@@ -168,7 +168,7 @@ public:
     quint16 vmeMethodLineNumber(int index);
     void setVmeMethod(int index, QV4::ValueRef function);
     QV4::ReturnedValue vmeProperty(int index);
-    void setVMEProperty(int index, const QV4::Value &v);
+    void setVMEProperty(int index, const QV4::ValueRef v);
 
     void connectAliasSignal(int index, bool indexInSignalRange);
 
@@ -220,7 +220,7 @@ public:
     QV4::ReturnedValue method(int);
 
     QV4::ReturnedValue readVarProperty(int);
-    void writeVarProperty(int, const QV4::Value &);
+    void writeVarProperty(int, const QV4::ValueRef);
     QVariant readPropertyAsVariant(int);
     void writeProperty(int, const QVariant &);
 
diff --git a/src/qml/qml/qqmlxmlhttprequest.cpp b/src/qml/qml/qqmlxmlhttprequest.cpp
index 84e99e6846..066a266991 100644
--- a/src/qml/qml/qqmlxmlhttprequest.cpp
+++ b/src/qml/qml/qqmlxmlhttprequest.cpp
@@ -100,12 +100,12 @@ static inline QQmlXMLHttpRequestData *xhrdata(QV8Engine *engine)
     return (QQmlXMLHttpRequestData *)engine->xmlHttpRequestData();
 }
 
-static ReturnedValue constructMeObject(const Value &thisObj, QV8Engine *e)
+static ReturnedValue constructMeObject(const ValueRef thisObj, QV8Engine *e)
 {
     ExecutionEngine *v4 = QV8Engine::getV4(e);
     Scope scope(v4);
     Scoped<Object> meObj(scope, v4->newObject());
-    meObj->put(ScopedString(scope, v4->newString(QStringLiteral("ThisObject"))), ScopedValue(scope, thisObj));
+    meObj->put(ScopedString(scope, v4->newString(QStringLiteral("ThisObject"))), thisObj);
     ScopedValue v(scope, QmlContextWrapper::qmlScope(e, e->callingContext(), 0));
     meObj->put(ScopedString(scope, v4->newString(QStringLiteral("ActivationObject"))), v);
     return meObj.asReturnedValue();
@@ -1557,7 +1557,7 @@ void QQmlXMLHttpRequest::dispatchCallback(const ValueRef me)
         if (!activationObject)
             v4->current->throwError(QStringLiteral("QQmlXMLHttpRequest: internal error: empty ActivationObject"));
 
-        QQmlContextData *callingContext = QmlContextWrapper::getContext(activationObject.asValue());
+        QQmlContextData *callingContext = QmlContextWrapper::getContext(activationObject);
         if (callingContext) {
             QV4::ScopedCallData callData(scope, 0);
             callData->thisObject = activationObject.asValue();
diff --git a/src/qml/qml/v8/qqmlbuiltinfunctions.cpp b/src/qml/qml/v8/qqmlbuiltinfunctions.cpp
index 926b5c34d8..e92eb40037 100644
--- a/src/qml/qml/v8/qqmlbuiltinfunctions.cpp
+++ b/src/qml/qml/v8/qqmlbuiltinfunctions.cpp
@@ -1072,10 +1072,10 @@ use \l{QtQml2::Qt::createQmlObject()}{Qt.createQmlObject()}.
 */
 ReturnedValue QtObject::method_createComponent(SimpleCallContext *ctx)
 {
-    const QString invalidArgs = QStringLiteral("Qt.createComponent(): Invalid arguments");
-    const QString invalidParent = QStringLiteral("Qt.createComponent(): Invalid parent object");
     if (ctx->callData->argc < 1 || ctx->callData->argc > 3)
-        ctx->throwError(invalidArgs);
+        ctx->throwError(QStringLiteral("Qt.createComponent(): Invalid arguments"));
+
+    Scope scope(ctx);
 
     QV8Engine *v8engine = ctx->engine->v8Engine;
     QQmlEngine *engine = v8engine->engine();
@@ -1095,31 +1095,32 @@ ReturnedValue QtObject::method_createComponent(SimpleCallContext *ctx)
 
     int consumedCount = 1;
     if (ctx->callData->argc > 1) {
-        Value lastArg = ctx->callData->args[ctx->callData->argc-1];
+        ScopedValue lastArg(scope, ctx->callData->args[ctx->callData->argc-1]);
 
         // The second argument could be the mode enum
         if (ctx->callData->args[1].isInteger()) {
             int mode = ctx->callData->args[1].integerValue();
             if (mode != int(QQmlComponent::PreferSynchronous) && mode != int(QQmlComponent::Asynchronous))
-                ctx->throwError(invalidArgs);
+                ctx->throwError(QStringLiteral("Qt.createComponent(): Invalid arguments"));
             compileMode = QQmlComponent::CompilationMode(mode);
             consumedCount += 1;
         } else {
             // The second argument could be the parent only if there are exactly two args
-            if ((ctx->callData->argc != 2) || !(lastArg.isObject() || lastArg.isNull()))
-                ctx->throwError(invalidArgs);
+            if ((ctx->callData->argc != 2) || !(lastArg->isObject() || lastArg->isNull()))
+                ctx->throwError(QStringLiteral("Qt.createComponent(): Invalid arguments"));
         }
 
         if (consumedCount < ctx->callData->argc) {
-            if (lastArg.isObject()) {
-                if (QV4::QObjectWrapper *qobjectWrapper = lastArg.as<QV4::QObjectWrapper>())
+            if (lastArg->isObject()) {
+                Scoped<QObjectWrapper> qobjectWrapper(scope, lastArg);
+                if (qobjectWrapper)
                     parentArg = qobjectWrapper->object();
                 if (!parentArg)
-                    ctx->throwError(invalidParent);
-            } else if (lastArg.isNull()) {
+                    ctx->throwError(QStringLiteral("Qt.createComponent(): Invalid parent object"));
+            } else if (lastArg->isNull()) {
                 parentArg = 0;
             } else {
-                ctx->throwError(invalidParent);
+                ctx->throwError(QStringLiteral("Qt.createComponent(): Invalid parent object"));
             }
         }
     }
@@ -1365,11 +1366,10 @@ static QV4::ReturnedValue writeToConsole(ConsoleLogTypes logType, SimpleCallCont
         if (i != 0)
             result.append(QLatin1Char(' '));
 
-        QV4::Value value = ctx->callData->args[i];
-        if (value.asArrayObject())
-            result.append(QStringLiteral("[") + value.toQStringNoThrow() + QStringLiteral("]"));
+        if (ctx->callData->args[i].asArrayObject())
+            result.append(QStringLiteral("[") + ctx->callData->args[i].toQStringNoThrow() + QStringLiteral("]"));
         else
-            result.append(value.toQStringNoThrow());
+            result.append(ctx->callData->args[i].toQStringNoThrow());
     }
 
     if (printStack) {
@@ -1836,19 +1836,21 @@ QV4::ReturnedValue GlobalExtensions::method_gc(SimpleCallContext *ctx)
 
 ReturnedValue GlobalExtensions::method_string_arg(SimpleCallContext *ctx)
 {
-    QString value = ctx->callData->thisObject.toQStringNoThrow();
     if (ctx->callData->argc != 1)
         V4THROW_ERROR("String.arg(): Invalid arguments");
 
-    QV4::Value arg = ctx->callData->args[0];
-    if (arg.isInteger())
-        return ctx->engine->newString(value.arg(arg.integerValue()))->asReturnedValue();
-    else if (arg.isDouble())
-        return ctx->engine->newString(value.arg(arg.doubleValue()))->asReturnedValue();
-    else if (arg.isBoolean())
-        return ctx->engine->newString(value.arg(arg.booleanValue()))->asReturnedValue();
+    QString value = ctx->callData->thisObject.toQString();
+
+    QV4::Scope scope(ctx);
+    QV4::ScopedValue arg(scope, ctx->callData->args[0]);
+    if (arg->isInteger())
+        return ctx->engine->newString(value.arg(arg->integerValue()))->asReturnedValue();
+    else if (arg->isDouble())
+        return ctx->engine->newString(value.arg(arg->doubleValue()))->asReturnedValue();
+    else if (arg->isBoolean())
+        return ctx->engine->newString(value.arg(arg->booleanValue()))->asReturnedValue();
 
-    return ctx->engine->newString(value.arg(arg.toQStringNoThrow()))->asReturnedValue();
+    return ctx->engine->newString(value.arg(arg->toQString()))->asReturnedValue();
 }
 
 
diff --git a/src/qml/qml/v8/qv8engine.cpp b/src/qml/qml/v8/qv8engine.cpp
index 20d81c2ac0..9211ffd484 100644
--- a/src/qml/qml/v8/qv8engine.cpp
+++ b/src/qml/qml/v8/qv8engine.cpp
@@ -205,7 +205,7 @@ static QV4::ReturnedValue arrayFromVariantList(QV8Engine *engine, const QVariant
     int len = list.count();
     a->arrayReserve(len);
     for (int ii = 0; ii < len; ++ii) {
-        a->arrayData[ii].value = QV4::Value::fromReturnedValue(engine->fromVariant(list.at(ii)));
+        a->arrayData[ii].value = engine->fromVariant(list.at(ii));
         a->arrayDataLen = ii + 1;
     }
     a->setArrayLengthUnchecked(len);
@@ -319,7 +319,7 @@ QV4::ReturnedValue QV8Engine::fromVariant(const QVariant &variant)
             QV4::Scoped<QV4::ArrayObject> a(scope, m_v4Engine->newArrayObject());
             a->arrayReserve(list.count());
             for (int ii = 0; ii < list.count(); ++ii) {
-                a->arrayData[ii].value = QV4::Value::fromReturnedValue(QV4::QObjectWrapper::wrap(m_v4Engine, list.at(ii)));
+                a->arrayData[ii].value = QV4::QObjectWrapper::wrap(m_v4Engine, list.at(ii));
                 a->arrayDataLen = ii + 1;
             }
             a->setArrayLengthUnchecked(list.count());
@@ -467,7 +467,7 @@ void QV8Engine::freezeObject(const QV4::ValueRef value)
     QV4::ScopedFunctionObject f(scope, m_freezeObject.value());
     QV4::ScopedCallData callData(scope, 1);
     callData->args[0] = value;
-    callData->thisObject = QV4::Value::fromObject(m_v4Engine->globalObject);
+    callData->thisObject = m_v4Engine->globalObject;
     f->call(callData);
 }
 
@@ -535,7 +535,7 @@ QV4::ReturnedValue QV8Engine::variantListToJS(const QVariantList &lst)
     QV4::Scoped<QV4::ArrayObject> a(scope, m_v4Engine->newArrayObject());
     a->arrayReserve(lst.size());
     for (int i = 0; i < lst.size(); i++) {
-        a->arrayData[i].value = QV4::Value::fromReturnedValue(variantToJS(lst.at(i)));
+        a->arrayData[i].value = variantToJS(lst.at(i));
         a->arrayDataLen = i + 1;
     }
     a->setArrayLengthUnchecked(lst.size());
@@ -586,7 +586,7 @@ QV4::ReturnedValue QV8Engine::variantMapToJS(const QVariantMap &vmap)
     for (it = vmap.constBegin(); it != vmap.constEnd(); ++it) {
         s = m_v4Engine->newIdentifier(it.key());
         QV4::Property *p = o->insertMember(s, QV4::Attr_Data);
-        p->value = QV4::Value::fromReturnedValue(variantToJS(it.value()));
+        p->value = variantToJS(it.value());
     }
     return o.asReturnedValue();
 }
diff --git a/src/qml/types/qqmldelegatemodel.cpp b/src/qml/types/qqmldelegatemodel.cpp
index 8f56ba968e..32d6505eff 100644
--- a/src/qml/types/qqmldelegatemodel.cpp
+++ b/src/qml/types/qqmldelegatemodel.cpp
@@ -63,10 +63,10 @@ struct DelegateModelGroupFunction: QV4::FunctionObject
 {
     Q_MANAGED
 
-    QV4::ReturnedValue (*code)(QQmlDelegateModelItem *item, uint flag, const QV4::Value &arg);
+    QV4::ReturnedValue (*code)(QQmlDelegateModelItem *item, uint flag, const QV4::ValueRef arg);
     uint flag;
 
-    DelegateModelGroupFunction(QV4::ExecutionContext *scope, uint flag, QV4::ReturnedValue (*code)(QQmlDelegateModelItem *item, uint flag, const QV4::Value &arg))
+    DelegateModelGroupFunction(QV4::ExecutionContext *scope, uint flag, QV4::ReturnedValue (*code)(QQmlDelegateModelItem *item, uint flag, const QV4::ValueRef arg))
         : FunctionObject(scope, /*name*/0)
         , code(code)
         , flag(flag)
@@ -105,8 +105,8 @@ public:
     QQmlDelegateModelEngineData(QV8Engine *engine);
     ~QQmlDelegateModelEngineData();
 
-    QV4::Value array(QV8Engine *engine, const QVector<QQmlChangeSet::Remove> &changes);
-    QV4::Value array(QV8Engine *engine, const QVector<QQmlChangeSet::Insert> &changes);
+    QV4::ReturnedValue array(QV8Engine *engine, const QVector<QQmlChangeSet::Remove> &changes);
+    QV4::ReturnedValue array(QV8Engine *engine, const QVector<QQmlChangeSet::Insert> &changes);
 
     QV4::PersistentValue changeProto;
 };
@@ -1540,7 +1540,7 @@ QQmlDelegateModelAttached *QQmlDelegateModel::qmlAttachedProperties(QObject *obj
     return new QQmlDelegateModelAttached(obj);
 }
 
-bool QQmlDelegateModelPrivate::insert(Compositor::insert_iterator &before, const QV4::Value &object, int groups)
+bool QQmlDelegateModelPrivate::insert(Compositor::insert_iterator &before, const QV4::ValueRef object, int groups)
 {
     if (!m_context->isValid())
         return false;
@@ -1548,13 +1548,16 @@ bool QQmlDelegateModelPrivate::insert(Compositor::insert_iterator &before, const
     QQmlDelegateModelItem *cacheItem = m_adaptorModel.createItem(m_cacheMetaType, m_context->engine(), -1);
     if (!cacheItem)
         return false;
-    QV4::Object *o = object.asObject();
-    if (!o)
+    QV4::ExecutionEngine *v4 = object->engine();
+    if (!v4)
         return false;
 
-    QV4::Scope scope(o->engine());
+    QV4::Scope scope(v4);
+    QV4::ScopedObject o(scope, object);
+    if (!o)
+        return false;
 
-    QV4::ObjectIterator it(o, QV4::ObjectIterator::EnumerableOnly|QV4::ObjectIterator::WithProtoChain);
+    QV4::ObjectIterator it(o.getPointer(), QV4::ObjectIterator::EnumerableOnly|QV4::ObjectIterator::WithProtoChain);
     QV4::ScopedValue propertyName(scope);
     while (1) {
         QV4::Value value;
@@ -1677,21 +1680,27 @@ int QQmlDelegateModelItemMetaType::parseGroups(const QStringList &groups) const
     return groupFlags;
 }
 
-int QQmlDelegateModelItemMetaType::parseGroups(const QV4::Value &groups) const
+int QQmlDelegateModelItemMetaType::parseGroups(const QV4::ValueRef groups) const
 {
     int groupFlags = 0;
-    if (QV4::String *s = groups.asString()) {
+    QV4::Scope scope(QV8Engine::getV4(v8Engine));
+
+    QV4::ScopedString s(scope, groups);
+    if (s) {
         const QString groupName = s->toQString();
         int index = groupNames.indexOf(groupName);
         if (index != -1)
             groupFlags |= 2 << index;
-    } else if (QV4::ArrayObject *array = groups.asArrayObject()) {
-        QV4::Scope scope(array->engine());
+        return groupFlags;
+    }
+
+    QV4::ScopedArrayObject array(scope, groups);
+    if (array) {
         QV4::ScopedValue v(scope);
         uint arrayLength = array->arrayLength();
         for (uint i = 0; i < arrayLength; ++i) {
             v = array->getIndexed(i);
-            const QString groupName = v->toQStringNoThrow();
+            const QString groupName = v->toQString();
             int index = groupNames.indexOf(groupName);
             if (index != -1)
                 groupFlags |= 2 << index;
@@ -1748,19 +1757,19 @@ QV4::ReturnedValue QQmlDelegateModelItem::set_groups(QV4::SimpleCallContext *ctx
     return QV4::Encode::undefined();
 }
 
-QV4::ReturnedValue QQmlDelegateModelItem::get_member(QQmlDelegateModelItem *thisItem, uint flag, const QV4::Value &)
+QV4::ReturnedValue QQmlDelegateModelItem::get_member(QQmlDelegateModelItem *thisItem, uint flag, const QV4::ValueRef)
 {
     return QV4::Encode(bool(thisItem->groups & (1 << flag)));
 }
 
-QV4::ReturnedValue QQmlDelegateModelItem::set_member(QQmlDelegateModelItem *cacheItem, uint flag, const QV4::Value &arg)
+QV4::ReturnedValue QQmlDelegateModelItem::set_member(QQmlDelegateModelItem *cacheItem, uint flag, const QV4::ValueRef arg)
 {
     if (!cacheItem->metaType->model)
         return QV4::Encode::undefined();
 
     QQmlDelegateModelPrivate *model = QQmlDelegateModelPrivate::get(cacheItem->metaType->model);
 
-    bool member = arg.toBoolean();
+    bool member = arg->toBoolean();
     uint groupFlag = (1 << flag);
     if (member == ((cacheItem->groups & groupFlag) != 0))
         return QV4::Encode::undefined();
@@ -1774,7 +1783,7 @@ QV4::ReturnedValue QQmlDelegateModelItem::set_member(QQmlDelegateModelItem *cach
     return QV4::Encode::undefined();
 }
 
-QV4::ReturnedValue QQmlDelegateModelItem::get_index(QQmlDelegateModelItem *thisItem, uint flag, const QV4::Value &)
+QV4::ReturnedValue QQmlDelegateModelItem::get_index(QQmlDelegateModelItem *thisItem, uint flag, const QV4::ValueRef)
 {
     return QV4::Encode((int)thisItem->groupIndex(Compositor::Group(flag)));
 }
@@ -2404,12 +2413,21 @@ QQmlV4Handle QQmlDelegateModelGroup::get(int index)
     return QQmlV4Handle(o);
 }
 
-bool QQmlDelegateModelGroupPrivate::parseIndex(const QV4::Value &value, int *index, Compositor::Group *group) const
+bool QQmlDelegateModelGroupPrivate::parseIndex(const QV4::ValueRef value, int *index, Compositor::Group *group) const
 {
-    if (value.isNumber()) {
-        *index = value.toInt32();
+    if (value->isNumber()) {
+        *index = value->toInt32();
         return true;
-    } else if (QQmlDelegateModelItemObject *object = value.as<QQmlDelegateModelItemObject>()) {
+    }
+
+    QV4::ExecutionEngine *v4 = value->engine();
+    if (!v4)
+        return false;
+
+    QV4::Scope scope(v4);
+    QV4::Scoped<QQmlDelegateModelItemObject> object(scope, value);
+
+    if (object) {
         QQmlDelegateModelItem * const cacheItem = object->item;
         if (QQmlDelegateModelPrivate *model = cacheItem->metaType->model
                 ? QQmlDelegateModelPrivate::get(cacheItem->metaType->model)
@@ -3275,20 +3293,16 @@ QQmlDelegateModelEngineData::~QQmlDelegateModelEngineData()
 {
 }
 
-QV4::Value QQmlDelegateModelEngineData::array(
-        QV8Engine *engine, const QVector<QQmlChangeSet::Remove> &changes)
+QV4::ReturnedValue QQmlDelegateModelEngineData::array(QV8Engine *engine, const QVector<QQmlChangeSet::Remove> &changes)
 {
     QV4::ExecutionEngine *v4 = QV8Engine::getV4(engine);
-    QV4::Object *array = new (v4->memoryManager) QQmlDelegateModelGroupRemoveArray(v4, changes);
-    return QV4::Value::fromObject(array);
+    return (new (v4->memoryManager) QQmlDelegateModelGroupRemoveArray(v4, changes))->asReturnedValue();
 }
 
-QV4::Value QQmlDelegateModelEngineData::array(
-        QV8Engine *engine, const QVector<QQmlChangeSet::Insert> &changes)
+QV4::ReturnedValue QQmlDelegateModelEngineData::array(QV8Engine *engine, const QVector<QQmlChangeSet::Insert> &changes)
 {
     QV4::ExecutionEngine *v4 = QV8Engine::getV4(engine);
-    QV4::Object *array = new (v4->memoryManager) QQmlDelegateModelGroupInsertArray(v4, changes);
-    return QV4::Value::fromObject(array);
+    return (new (v4->memoryManager) QQmlDelegateModelGroupInsertArray(v4, changes))->asReturnedValue();
 }
 
 QT_END_NAMESPACE
diff --git a/src/qml/types/qqmldelegatemodel_p_p.h b/src/qml/types/qqmldelegatemodel_p_p.h
index aa4e0c30e2..8205b5350f 100644
--- a/src/qml/types/qqmldelegatemodel_p_p.h
+++ b/src/qml/types/qqmldelegatemodel_p_p.h
@@ -78,7 +78,7 @@ public:
     void initializePrototype();
 
     int parseGroups(const QStringList &groupNames) const;
-    int parseGroups(const QV4::Value &groupNames) const;
+    int parseGroups(const QV4::ValueRef groupNames) const;
 
     QPointer<QQmlDelegateModel> model;
     const int groupCount;
@@ -136,9 +136,9 @@ public:
     static QV4::ReturnedValue get_model(QV4::SimpleCallContext *ctx);
     static QV4::ReturnedValue get_groups(QV4::SimpleCallContext *ctx);
     static QV4::ReturnedValue set_groups(QV4::SimpleCallContext *ctx);
-    static QV4::ReturnedValue get_member(QQmlDelegateModelItem *thisItem, uint flag, const QV4::Value &);
-    static QV4::ReturnedValue set_member(QQmlDelegateModelItem *thisItem, uint flag, const QV4::Value &arg);
-    static QV4::ReturnedValue get_index(QQmlDelegateModelItem *thisItem, uint flag, const QV4::Value &arg);
+    static QV4::ReturnedValue get_member(QQmlDelegateModelItem *thisItem, uint flag, const QV4::ValueRef);
+    static QV4::ReturnedValue set_member(QQmlDelegateModelItem *thisItem, uint flag, const QV4::ValueRef arg);
+    static QV4::ReturnedValue get_index(QQmlDelegateModelItem *thisItem, uint flag, const QV4::ValueRef arg);
 
     QV4::ExecutionEngine *v4;
     QQmlDelegateModelItemMetaType * const metaType;
@@ -226,7 +226,7 @@ public:
     void initPackage(int index, QQuickPackage *package);
     void destroyingPackage(QQuickPackage *package);
 
-    bool parseIndex(const QV4::Value &value, int *index, Compositor::Group *group) const;
+    bool parseIndex(const QV4::ValueRef value, int *index, Compositor::Group *group) const;
     bool parseGroupArgs(
             QQmlV4Function *args, Compositor::Group *group, int *index, int *count, int *groups) const;
 
@@ -289,7 +289,7 @@ public:
     void emitChanges();
     void emitModelUpdated(const QQmlChangeSet &changeSet, bool reset);
 
-    bool insert(Compositor::insert_iterator &before, const QV4::Value &object, int groups);
+    bool insert(Compositor::insert_iterator &before, const QV4::ValueRef object, int groups);
 
     static void group_append(QQmlListProperty<QQmlDelegateModelGroup> *property, QQmlDelegateModelGroup *group);
     static int group_count(QQmlListProperty<QQmlDelegateModelGroup> *property);