Disallow parent changes for QML created objects

Currently this is protected with a QML_PARENT_TEST environment variable
to allow the rest of QtQuick to be updated before it is enforced.

Change-Id: I4dd3644cbbce91d67f24c9556637f97eafb00638
Reviewed-by: Kent Hansen <kent.hansen@nokia.com>
Reviewed-by: Michael Brasser <michael.brasser@nokia.com>

6 files changed, 36 insertions, 27 deletions

diff --git a/src/qml/qml/qqmlcompiler.cpp b/src/qml/qml/qqmlcompiler.cpp
index f8625861af..218d719634 100644
--- a/src/qml/qml/qqmlcompiler.cpp
+++ b/src/qml/qml/qqmlcompiler.cpp
@@ -1155,7 +1155,7 @@ bool QQmlCompiler::buildObject(QQmlScript::Object *obj, const BindingContext &ct
     return true;
 }
 
-void QQmlCompiler::genObject(QQmlScript::Object *obj)
+void QQmlCompiler::genObject(QQmlScript::Object *obj, bool parentToSuper)
 {
     QQmlCompiledData::TypeReference &tr = output->types[obj->type];
     if (tr.type && obj->metatype->metaObject() == &QQmlComponent::staticMetaObject) {
@@ -1173,6 +1173,7 @@ void QQmlCompiler::genObject(QQmlScript::Object *obj)
         create.type = obj->type;
         create.line = obj->location.start.line;
         create.column = obj->location.start.column;
+        create.parentToSuper = parentToSuper;
         output->addInstruction(create);
 
     } else {
@@ -1186,6 +1187,7 @@ void QQmlCompiler::genObject(QQmlScript::Object *obj)
                 create.data = output->indexForByteArray(obj->custom);
             create.type = obj->type;
             create.isRoot = (compileState->root == obj);
+            create.parentToSuper = parentToSuper;
             output->addInstruction(create);
         } else {
             Instruction::CreateQMLObject create;
@@ -1975,31 +1977,25 @@ void QQmlCompiler::genPropertyAssignment(QQmlScript::Property *prop,
                  v->type == Value::ValueInterceptor);
 
         if (v->type == Value::ValueSource) {
-            genObject(v->object);
+            genObject(v->object, valueTypeProperty?true:false);
 
             Instruction::StoreValueSource store;
-            if (valueTypeProperty) {
+            if (valueTypeProperty)
                 store.property = genValueTypeData(prop, valueTypeProperty);
-                store.owner = 1;
-            } else {
+            else
                 store.property = prop->core;
-                store.owner = 0;
-            }
             QQmlType *valueType = toQmlType(v->object);
             store.castValue = valueType->propertyValueSourceCast();
             output->addInstruction(store);
 
         } else if (v->type == Value::ValueInterceptor) {
-            genObject(v->object);
+            genObject(v->object, valueTypeProperty?true:false);
 
             Instruction::StoreValueInterceptor store;
-            if (valueTypeProperty) {
+            if (valueTypeProperty)
                 store.property = genValueTypeData(prop, valueTypeProperty);
-                store.owner = 1;
-            } else {
+            else
                 store.property = prop->core;
-                store.owner = 0;
-            }
             QQmlType *valueType = toQmlType(v->object);
             store.castValue = valueType->propertyValueInterceptorCast();
             output->addInstruction(store);
diff --git a/src/qml/qml/qqmlcompiler_p.h b/src/qml/qml/qqmlcompiler_p.h
index 2339b6ceea..4b730c2e20 100644
--- a/src/qml/qml/qqmlcompiler_p.h
+++ b/src/qml/qml/qqmlcompiler_p.h
@@ -373,7 +373,7 @@ private:
     bool checkValidId(QQmlScript::Value *, const QString &);
 
 
-    void genObject(QQmlScript::Object *obj);
+    void genObject(QQmlScript::Object *obj, bool parentToSuper = false);
     void genObjectBody(QQmlScript::Object *obj);
     void genValueTypeProperty(QQmlScript::Object *obj,QQmlScript::Property *);
     void genComponent(QQmlScript::Object *obj);
diff --git a/src/qml/qml/qqmldata_p.h b/src/qml/qml/qqmldata_p.h
index eba2f4df6e..879d59722b 100644
--- a/src/qml/qml/qqmldata_p.h
+++ b/src/qml/qml/qqmldata_p.h
@@ -80,7 +80,7 @@ public:
     QQmlData()
         : ownMemory(true), ownContext(false), indestructible(true), explicitIndestructibleSet(false), 
           hasTaintedV8Object(false), isQueuedForDeletion(false), rootObjectInCreation(false),
-          hasVMEMetaObject(false), notifyList(0), context(0), outerContext(0),
+          hasVMEMetaObject(false), parentFrozen(false), notifyList(0), context(0), outerContext(0),
           bindings(0), signalHandlers(0), nextContextObject(0), prevContextObject(0), bindingBitsSize(0), bindingBits(0),
           lineNumber(0), columnNumber(0), compiledData(0), deferredIdx(0), v8objectid(0),
           propertyCache(0), guards(0), extendedData(0) {
@@ -122,7 +122,8 @@ public:
      */
     quint32 rootObjectInCreation:1;
     quint32 hasVMEMetaObject:1;
-    quint32 dummy:24;
+    quint32 parentFrozen:1;
+    quint32 dummy:23;
 
     struct NotifyList {
         quint64 connectionMask;
diff --git a/src/qml/qml/qqmlengine.cpp b/src/qml/qml/qqmlengine.cpp
index 7b4b827409..832f58bcfa 100644
--- a/src/qml/qml/qqmlengine.cpp
+++ b/src/qml/qml/qqmlengine.cpp
@@ -1383,10 +1383,23 @@ void QQmlData::destroyed(QObject *object)
         delete this;
 }
 
+DEFINE_BOOL_CONFIG_OPTION(parentTest, QML_PARENT_TEST);
+
 void QQmlData::parentChanged(QObject *object, QObject *parent)
 {
-    Q_UNUSED(object);
-    Q_UNUSED(parent);
+    if (parentTest()) {
+        if (parentFrozen && !QObjectPrivate::get(object)->wasDeleted) {
+            QString on;
+            QString pn;
+
+            { QDebug dbg(&on); dbg << object; on = on.left(on.length() - 1); }
+            { QDebug dbg(&pn); dbg << parent; pn = pn.left(pn.length() - 1); }
+
+            qFatal("Object %s has had its parent frozen by QML and cannot be changed.\n"
+                   "User code is attempting to change it to %s.\n"
+                   "This behavior is NOT supported!", qPrintable(on), qPrintable(pn));
+        }
+    }
 }
 
 bool QQmlData::hasBindingBit(int bit) const
diff --git a/src/qml/qml/qqmlinstruction_p.h b/src/qml/qml/qqmlinstruction_p.h
index bd279d66d8..8b7dc383f8 100644
--- a/src/qml/qml/qqmlinstruction_p.h
+++ b/src/qml/qml/qqmlinstruction_p.h
@@ -200,6 +200,7 @@ union QQmlInstruction
         ushort column;
         ushort line; 
         bool isRoot;
+        bool parentToSuper;
     };
     struct instr_createSimple {
         QML_INSTR_HEADER
@@ -208,6 +209,7 @@ union QQmlInstruction
         int type;
         ushort column;
         ushort line; 
+        bool parentToSuper;
     };
     struct instr_storeMeta {
         QML_INSTR_HEADER
@@ -222,13 +224,11 @@ union QQmlInstruction
     struct instr_assignValueSource {
         QML_INSTR_HEADER
         QQmlPropertyRawData property;
-        int owner;
         int castValue;
     };
     struct instr_assignValueInterceptor {
         QML_INSTR_HEADER
         QQmlPropertyRawData property;
-        int owner;
         int castValue;
     };
     struct instr_initV8Bindings {
diff --git a/src/qml/qml/qqmlvme.cpp b/src/qml/qml/qqmlvme.cpp
index bb245198bf..b9924e384c 100644
--- a/src/qml/qml/qqmlvme.cpp
+++ b/src/qml/qml/qqmlvme.cpp
@@ -609,13 +609,14 @@ QObject *QQmlVME::run(QList<QQmlError> *errors,
                 customParser->setCustomData(o, DATAS.at(instr.data));
             }
             if (!objects.isEmpty()) {
-                QObject *parent = objects.top();
+                QObject *parent = objects.at(objects.count() - 1 - (instr.parentToSuper?1:0));
 #if 0 // ### refactor
                 if (o->isWidgetType() && parent->isWidgetType()) 
                     static_cast<QWidget*>(o)->setParent(static_cast<QWidget*>(parent));
                 else 
 #endif
                     QQml_setParent_noEvent(o, parent);
+                ddata->parentFrozen = true;
             }
             objects.push(o);
         QML_END_INSTR(CreateCppObject)
@@ -642,9 +643,10 @@ QObject *QQmlVME::run(QList<QQmlError> *errors,
             ddata->prevContextObject = &CTXT->contextObjects; 
             CTXT->contextObjects = ddata; 
 
-            QObject *parent = objects.top();                                                                    
+            QObject *parent = objects.at(objects.count() - 1 - (instr.parentToSuper?1:0));
             QQml_setParent_noEvent(o, parent);                                                        
 
+            ddata->parentFrozen = true;
             objects.push(o);
         QML_END_INSTR(CreateSimpleObject)
 
@@ -905,19 +907,16 @@ QObject *QQmlVME::run(QList<QQmlError> *errors,
         QML_BEGIN_INSTR(StoreValueSource)
             QObject *obj = objects.pop();
             QQmlPropertyValueSource *vs = reinterpret_cast<QQmlPropertyValueSource *>(reinterpret_cast<char *>(obj) + instr.castValue);
-            QObject *target = objects.at(objects.count() - 1 - instr.owner);
-
-            obj->setParent(target);
+            QObject *target = obj->parent();
             vs->setTarget(QQmlPropertyPrivate::restore(target, instr.property, CTXT));
         QML_END_INSTR(StoreValueSource)
 
         QML_BEGIN_INSTR(StoreValueInterceptor)
             QObject *obj = objects.pop();
             QQmlPropertyValueInterceptor *vi = reinterpret_cast<QQmlPropertyValueInterceptor *>(reinterpret_cast<char *>(obj) + instr.castValue);
-            QObject *target = objects.at(objects.count() - 1 - instr.owner);
+            QObject *target = obj->parent();
             QQmlProperty prop = 
                 QQmlPropertyPrivate::restore(target, instr.property, CTXT);
-            obj->setParent(target);
             vi->setTarget(prop);
             QQmlVMEMetaObject *mo = QQmlVMEMetaObject::get(target);
             Q_ASSERT(mo);