Further work towards an exact GC

Add some more convenience in the helper classes
in qscopedvalue_p.h
Make accesses to CallData safer, and change
ExecutionEngine::newObject() to return a safe
pointer.

Change-Id: I980909754ce9681cf6faa1355bab3a1e5d6dd186
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>

2 files changed, 28 insertions, 19 deletions

diff --git a/src/qml/types/qqmldelegatemodel.cpp b/src/qml/types/qqmldelegatemodel.cpp
index 0457adb348..b9f78da96e 100644
--- a/src/qml/types/qqmldelegatemodel.cpp
+++ b/src/qml/types/qqmldelegatemodel.cpp
@@ -83,10 +83,12 @@ struct DelegateModelGroupFunction: QV4::FunctionObject
 
     static QV4::ReturnedValue call(QV4::Managed *that, QV4::CallData *callData)
     {
-        DelegateModelGroupFunction *f = static_cast<DelegateModelGroupFunction *>(that);
-        QQmlDelegateModelItemObject *o = callData->thisObject.as<QQmlDelegateModelItemObject>();
+        QV4::ExecutionEngine *v4 = that->engine();
+        QV4::Scope scope(v4);
+        QV4::Scoped<DelegateModelGroupFunction> f(scope, that, QV4::Scoped<DelegateModelGroupFunction>::Cast);
+        QV4::Scoped<QQmlDelegateModelItemObject> o(scope, callData->thisObject);
         if (!o)
-            that->engine()->current->throwTypeError(QStringLiteral("Not a valid VisualData object"));
+            v4->current->throwTypeError(QStringLiteral("Not a valid VisualData object"));
 
         QV4::Value v = callData->argc ? callData->args[0] : QV4::Value::undefinedValue();
         return f->code(o->item, f->flag, v);
@@ -1622,8 +1624,9 @@ void QQmlDelegateModelItemMetaType::initializePrototype()
 {
     QQmlDelegateModelEngineData *data = engineData(v8Engine);
     QV4::ExecutionEngine *v4 = QV8Engine::getV4(v8Engine);
+    QV4::Scope scope(v4);
 
-    QV4::Object *proto = v4->newObject();
+    QV4::Scoped<QV4::Object> proto(scope, v4->newObject());
     proto->defineAccessorProperty(v4, QStringLiteral("model"), QQmlDelegateModelItem::get_model, 0);
     proto->defineAccessorProperty(v4, QStringLiteral("groups"), QQmlDelegateModelItem::get_groups, QQmlDelegateModelItem::set_groups);
     QV4::Property *p = proto->insertMember(v4->newString(QStringLiteral("isUnresolved")),
@@ -1656,7 +1659,7 @@ void QQmlDelegateModelItemMetaType::initializePrototype()
         p = proto->insertMember(v4->newString(propertyName), QV4::Attr_Accessor|QV4::Attr_NotConfigurable|QV4::Attr_NotEnumerable);
         p->setGetter(new (v4->memoryManager) DelegateModelGroupFunction(v4->rootContext, i + 1, QQmlDelegateModelItem::get_index));
     }
-    modelItemProto = QV4::Value::fromObject(proto);
+    modelItemProto = proto;
 }
 
 int QQmlDelegateModelItemMetaType::parseGroups(const QStringList &groups) const
@@ -3233,15 +3236,16 @@ private:
 QQmlDelegateModelEngineData::QQmlDelegateModelEngineData(QV8Engine *e)
 {
     QV4::ExecutionEngine *v4 = QV8Engine::getV4(e);
+    QV4::Scope scope(v4);
 
-    QV4::Object *proto = v4->newObject();
+    QV4::Scoped<QV4::Object> proto(scope, v4->newObject());
     QV4::Property *p = proto->insertMember(v4->newString(QStringLiteral("index")), QV4::Attr_Accessor|QV4::Attr_NotConfigurable|QV4::Attr_NotEnumerable);
     p->setGetter(v4->newBuiltinFunction(v4->rootContext, v4->id_undefined, QQmlDelegateModelGroupChange::method_get_index));
     p = proto->insertMember(v4->newString(QStringLiteral("count")), QV4::Attr_Accessor|QV4::Attr_NotConfigurable|QV4::Attr_NotEnumerable);
     p->setGetter(v4->newBuiltinFunction(v4->rootContext, v4->id_undefined, QQmlDelegateModelGroupChange::method_get_count));
     p = proto->insertMember(v4->newString(QStringLiteral("moveId")), QV4::Attr_Accessor|QV4::Attr_NotConfigurable|QV4::Attr_NotEnumerable);
     p->setGetter(v4->newBuiltinFunction(v4->rootContext, v4->id_undefined, QQmlDelegateModelGroupChange::method_get_moveId));
-    changeProto = QV4::Value::fromObject(proto);
+    changeProto = proto;
 }
 
 QQmlDelegateModelEngineData::~QQmlDelegateModelEngineData()
diff --git a/src/qml/types/qquickworkerscript.cpp b/src/qml/types/qquickworkerscript.cpp
index 4e39682d84..d80df760fa 100644
--- a/src/qml/types/qquickworkerscript.cpp
+++ b/src/qml/types/qquickworkerscript.cpp
@@ -177,7 +177,7 @@ public:
     };
 
     QHash<int, WorkerScript *> workers;
-    QV4::Value getWorker(WorkerScript *);
+    QV4::ReturnedValue getWorker(WorkerScript *);
 
     int m_nextId;
 
@@ -282,9 +282,9 @@ QV4::ReturnedValue QQuickWorkerScriptEnginePrivate::method_sendMessage(QV4::Simp
 {
     WorkerEngine *engine = (WorkerEngine*)ctx->engine->v8Engine;
 
-    int id = ctx->argument(1).toInt32();
+    int id = ctx->argumentCount > 1 ? ctx->arguments[1].toInt32() : 0;
 
-    QByteArray data = QV4::Serialize::serialize(ctx->argument(2), engine);
+    QByteArray data = QV4::Serialize::serialize(ctx->argumentCount > 2 ? ctx->arguments[2] : QV4::Value::undefinedValue(), engine);
 
     QMutexLocker locker(&engine->p->m_lock);
     WorkerScript *script = engine->p->workers.value(id);
@@ -298,27 +298,29 @@ QV4::ReturnedValue QQuickWorkerScriptEnginePrivate::method_sendMessage(QV4::Simp
 }
 
 // Requires handle scope and context scope
-QV4::Value QQuickWorkerScriptEnginePrivate::getWorker(WorkerScript *script)
+QV4::ReturnedValue QQuickWorkerScriptEnginePrivate::getWorker(WorkerScript *script)
 {
     if (!script->initialized) {
         script->initialized = true;
 
         QV4::ExecutionEngine *v4 = QV8Engine::getV4(workerEngine);
+        QV4::Scope scope(v4);
 
         script->object = QV4::QmlContextWrapper::urlScope(workerEngine, script->source);
 
-        QV4::QmlContextWrapper *w = script->object.value().asObject()->as<QV4::QmlContextWrapper>();
+        QV4::Scoped<QV4::QmlContextWrapper> w(scope, script->object.value());
+        Q_ASSERT(!!w);
         w->setReadOnly(false);
 
-        QV4::Object *api = v4->newObject();
+        QV4::Scoped<QV4::Object> api(scope, v4->newObject());
         api->put(v4->newString("sendMessage"), workerEngine->sendFunction(script->id));
 
-        script->object.value().asObject()->put(v4->newString("WorkerScript"), QV4::Value::fromObject(api));
+        script->object.value().asObject()->put(v4->newString("WorkerScript"), api.asValue());
 
         w->setReadOnly(true);
     }
 
-    return script->object.value();
+    return script->object.value().asReturnedValue();
 }
 
 bool QQuickWorkerScriptEnginePrivate::event(QEvent *event)
@@ -386,12 +388,15 @@ void QQuickWorkerScriptEnginePrivate::processLoad(int id, const QUrl &url)
         if (!script)
             return;
         script->source = url;
-        QV4::Value activation = getWorker(script);
-        if (activation.isEmpty())
-            return;
 
         QV4::ExecutionEngine *v4 = QV8Engine::getV4(workerEngine);
-        QV4::Script program(v4, activation.asObject(), sourceCode, url.toString());
+        QV4::Scope scope(v4);
+
+        QV4::Scoped<QV4::Object> activation(scope, getWorker(script));
+        if (!activation)
+            return;
+
+        QV4::Script program(v4, activation.getPointer(), sourceCode, url.toString());
 
         QV4::ExecutionContext *ctx = v4->current;
         try {