Prevent the root object from being garbage collected.

Passing the root object as a return value from a C++ function could
cause the indestructible flag to be set to false.

Change-Id: Ib70c666f0d0ffbb48bca1996c2517fbccafa5dc1
Reviewed-by: Chris Adams <christopher.adams@nokia.com>

3 files changed, 13 insertions, 8 deletions

diff --git a/src/qml/qml/qqmlcomponent.cpp b/src/qml/qml/qqmlcomponent.cpp
index 6cd5cf6cec..416178e3e1 100644
--- a/src/qml/qml/qqmlcomponent.cpp
+++ b/src/qml/qml/qqmlcomponent.cpp
@@ -829,7 +829,10 @@ QQmlComponentPrivate::beginCreate(QQmlContextData *context)
     if (rv) {
         QQmlData *ddata = QQmlData::get(rv);
         Q_ASSERT(ddata);
+        //top level objects should never get JS ownership.
+        //if JS ownership is needed this needs to be explicitly undone (like in component.createObject())
         ddata->indestructible = true;
+        ddata->explicitIndestructibleSet = true;
     }
 
     if (enginePriv->isDebugging && rv) {
@@ -1120,7 +1123,8 @@ void QQmlComponent::createObject(QQmlV8Function *args)
     d->completeCreate();
 
     Q_ASSERT(QQmlData::get(rv));
-    QQmlData::get(rv)->setImplicitDestructible();
+    QQmlData::get(rv)->explicitIndestructibleSet = false;
+    QQmlData::get(rv)->indestructible = false;
 
     if (!rv)
         args->returnValue(v8::Null());
@@ -1255,10 +1259,6 @@ void QQmlComponentPrivate::initializeObjectWithInitialProperties(v8::Handle<v8::
         v8::Handle<v8::Value> args[] = { object, valuemap };
         v8::Handle<v8::Function>::Cast(function)->Call(v8engine->global(), 2, args);
     }
-
-    QQmlData *ddata = QQmlData::get(toCreate);
-    Q_ASSERT(ddata);
-    ddata->setImplicitDestructible();
 }
 
 
diff --git a/src/qml/qml/qqmlincubator.cpp b/src/qml/qml/qqmlincubator.cpp
index aa9777d89e..fad2ae2f28 100644
--- a/src/qml/qml/qqmlincubator.cpp
+++ b/src/qml/qml/qqmlincubator.cpp
@@ -293,8 +293,9 @@ void QQmlIncubatorPrivate::incubate(QQmlVME::Interrupt &i)
         if (result) {
             QQmlData *ddata = QQmlData::get(result);
             Q_ASSERT(ddata);
+            //see QQmlComponent::beginCreate for explanation of indestructible
             ddata->indestructible = true;
-
+            ddata->explicitIndestructibleSet = true;
             q->setInitialState(result);
         }
 
diff --git a/src/qml/qml/v8/qqmlbuiltinfunctions.cpp b/src/qml/qml/v8/qqmlbuiltinfunctions.cpp
index 57a1cb0dcb..c8f178db08 100644
--- a/src/qml/qml/v8/qqmlbuiltinfunctions.cpp
+++ b/src/qml/qml/v8/qqmlbuiltinfunctions.cpp
@@ -1097,7 +1097,9 @@ v8::Handle<v8::Value> createQmlObject(const v8::Arguments &args)
 
     QObject *obj = component.beginCreate(effectiveContext);
     if (obj) {
-        QQmlData::get(obj, true)->setImplicitDestructible();
+        QQmlData::get(obj, true)->explicitIndestructibleSet = false;
+        QQmlData::get(obj)->indestructible = false;
+
 
         obj->setParent(parentArg);
 
@@ -1208,7 +1210,9 @@ v8::Handle<v8::Value> createComponent(const v8::Arguments &args)
     QUrl url = context->resolvedUrl(QUrl(arg));
     QQmlComponent *c = new QQmlComponent(engine, url, compileMode, parentArg);
     QQmlComponentPrivate::get(c)->creationContext = effectiveContext;
-    QQmlData::get(c, true)->setImplicitDestructible();
+    QQmlData::get(c, true)->explicitIndestructibleSet = false;
+    QQmlData::get(c)->indestructible = false;
+
     return v8engine->newQObject(c);
 }