Fix property access and method invocation on value types that use inheritance

For gadgets/value types we use moc's static_metacall, which doesn't call the
parent class implementation. Therefore before placing a static metacall we
must resolve the indicies and find the right meta-object.

Change-Id: I258e3d9ecfc704498c68772dc42b16134a3bfd83
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>
Reviewed-by: Alex Blasche <alexander.blasche@theqtcompany.com>

4 files changed, 52 insertions, 6 deletions

diff --git a/src/qml/qml/qqmlpropertycache.cpp b/src/qml/qml/qqmlpropertycache.cpp
index b5bc29aaa6..182e6a7814 100644
--- a/src/qml/qml/qqmlpropertycache.cpp
+++ b/src/qml/qml/qqmlpropertycache.cpp
@@ -1510,6 +1510,39 @@ bool QQmlMetaObject::canConvert(const QQmlMetaObject &from, const QQmlMetaObject
     return false;
 }
 
+void QQmlMetaObject::resolveGadgetMethodOrPropertyIndex(QMetaObject::Call type, const QMetaObject **metaObject, int *index)
+{
+    int offset;
+
+    switch (type) {
+    case QMetaObject::ReadProperty:
+    case QMetaObject::WriteProperty:
+    case QMetaObject::ResetProperty:
+    case QMetaObject::QueryPropertyDesignable:
+    case QMetaObject::QueryPropertyEditable:
+    case QMetaObject::QueryPropertyScriptable:
+    case QMetaObject::QueryPropertyStored:
+    case QMetaObject::QueryPropertyUser:
+        offset = (*metaObject)->propertyOffset();
+        while (*index < offset) {
+            *metaObject = (*metaObject)->superClass();
+            offset = (*metaObject)->propertyOffset();
+        }
+        break;
+    case QMetaObject::InvokeMetaMethod:
+        offset = (*metaObject)->methodOffset();
+        while (*index < offset) {
+            *metaObject = (*metaObject)->superClass();
+            offset = (*metaObject)->methodOffset();
+        }
+        break;
+    default:
+        Q_UNIMPLEMENTED();
+    }
+
+    *index -= offset;
+}
+
 QQmlPropertyCache *QQmlMetaObject::propertyCache(QQmlEnginePrivate *e) const
 {
     if (_m.isNull()) return 0;
@@ -1652,8 +1685,11 @@ void QQmlObjectOrGadget::metacall(QMetaObject::Call type, int index, void **argv
 {
     if (ptr.isT1())
         QMetaObject::metacall(ptr.asT1(), type, index, argv);
-    else
-        _m.asT1()->metaObject()->d.static_metacall(reinterpret_cast<QObject*>(ptr.asT2()), type, index, argv);
+    else {
+        const QMetaObject *metaObject = _m.asT1()->metaObject();
+        QQmlMetaObject::resolveGadgetMethodOrPropertyIndex(type, &metaObject, &index);
+        metaObject->d.static_metacall(reinterpret_cast<QObject*>(ptr.asT2()), type, index, argv);
+    }
 }
 
 QT_END_NAMESPACE
diff --git a/src/qml/qml/qqmlpropertycache_p.h b/src/qml/qml/qqmlpropertycache_p.h
index 77bbd3dc14..033ff1de31 100644
--- a/src/qml/qml/qqmlpropertycache_p.h
+++ b/src/qml/qml/qqmlpropertycache_p.h
@@ -432,6 +432,10 @@ public:
 
     static bool canConvert(const QQmlMetaObject &from, const QQmlMetaObject &to);
 
+    // static_metacall (on Gadgets) doesn't call the base implementation and therefore
+    // we need a helper to find the correct meta object and property/method index.
+    static void resolveGadgetMethodOrPropertyIndex(QMetaObject::Call type, const QMetaObject **metaObject, int *index);
+
 protected:
     QBiPointer<QQmlPropertyCache, const QMetaObject> _m;
 };
diff --git a/src/qml/qml/qqmlvaluetype.cpp b/src/qml/qml/qqmlvaluetype.cpp
index e901a9c0d7..7f0e3a3a61 100644
--- a/src/qml/qml/qqmlvaluetype.cpp
+++ b/src/qml/qml/qqmlvaluetype.cpp
@@ -231,7 +231,9 @@ void QQmlValueType::objectDestroyed(QObject *)
 
 int QQmlValueType::metaCall(QObject *, QMetaObject::Call type, int _id, void **argv)
 {
-    d.static_metacall(reinterpret_cast<QObject*>(gadgetPtr), type, _id, argv);
+    const QMetaObject *mo = _metaObject;
+    QQmlMetaObject::resolveGadgetMethodOrPropertyIndex(type, &mo, &_id);
+    mo->d.static_metacall(reinterpret_cast<QObject*>(gadgetPtr), type, _id, argv);
     return _id;
 }
 
diff --git a/src/qml/qml/qqmlvaluetypewrapper.cpp b/src/qml/qml/qqmlvaluetypewrapper.cpp
index 332cfefde9..85a391fd98 100644
--- a/src/qml/qml/qqmlvaluetypewrapper.cpp
+++ b/src/qml/qml/qqmlvaluetypewrapper.cpp
@@ -307,11 +307,15 @@ ReturnedValue QQmlValueTypeWrapper::get(Managed *m, String *name, bool *hasPrope
     if (result->propType == metatype) { \
         cpptype v; \
         void *args[] = { &v, 0 }; \
-        metaObject->d.static_metacall(reinterpret_cast<QObject*>(gadget), QMetaObject::ReadProperty, result->coreIndex, args); \
+        metaObject->d.static_metacall(reinterpret_cast<QObject*>(gadget), QMetaObject::ReadProperty, index, args); \
         return QV4::Encode(constructor(v)); \
     }
 
     const QMetaObject *metaObject = r->d()->propertyCache->metaObject();
+
+    int index = result->coreIndex;
+    QQmlMetaObject::resolveGadgetMethodOrPropertyIndex(QMetaObject::ReadProperty, &metaObject, &index);
+
     void *gadget = r->d()->gadget();
 
     // These four types are the most common used by the value type wrappers
@@ -322,9 +326,9 @@ ReturnedValue QQmlValueTypeWrapper::get(Managed *m, String *name, bool *hasPrope
 
     QVariant v(result->propType, (void *)0);
     void *args[] = { v.data(), 0 };
-    metaObject->d.static_metacall(reinterpret_cast<QObject*>(gadget), QMetaObject::ReadProperty, result->coreIndex, args);
+    metaObject->d.static_metacall(reinterpret_cast<QObject*>(gadget), QMetaObject::ReadProperty, index, args);
     return QV8Engine::fromVariant(v4, v);
-#undef VALUE_TYPE_ACCESSOR
+#undef VALUE_TYPE_LOAD
 }
 
 void QQmlValueTypeWrapper::put(Managed *m, String *name, const ValueRef value)