Ensure that dynamic property storing QObject ptr notifies on delete

Previously, when a QObject ptr was stored in a dynamic variant
property, the value of the property could change (to a zero ptr)
if the QObject was deleted without a notify signal being emitted
by the QDeclarativeVMEMetaObject which stores the property.

This commit ensures that such a notify signal is emitted correctly.

Task-number: QTBUG-23451
Change-Id: I5689abd984b177737f8d5f18950838b73ebde328
Reviewed-by: Martin Jones <martin.jones@nokia.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/src/qml/qml/qqmlvmemetaobject_p.h b/src/qml/qml/qqmlvmemetaobject_p.h
index deee989383..84c88fdd7b 100644
--- a/src/qml/qml/qqmlvmemetaobject_p.h
+++ b/src/qml/qml/qqmlvmemetaobject_p.h
@@ -136,6 +136,19 @@ struct QQmlVMEMetaData
     }
 };
 
+class QQmlVMEMetaObject;
+class QQmlVMEVariantQObjectPtr : public QQmlGuard<QObject>
+{
+public:
+    inline QQmlVMEVariantQObjectPtr();
+    inline ~QQmlVMEVariantQObjectPtr();
+    inline void objectDestroyed(QObject *);
+    inline void setGuardedValue(QObject *obj, QQmlVMEMetaObject *target, int index);
+
+    QQmlVMEMetaObject *m_target;
+    int m_index;
+};
+
 class QV8QObjectWrapper;
 class QQmlVMEVariant;
 class QQmlRefCount;
@@ -163,6 +176,7 @@ protected:
 
 private:
     friend class QQmlVMEMetaObjectEndpoint;
+    friend class QQmlVMEVariantQObjectPtr;
 
     QObject *object;
     QQmlCompiledData *compiledData;