QMetatype: Register the QMetaObject of a Q_ENUM or Q_FLAG

Change-Id: Id1343c3fb51d88a43d4d97e8859dbe2b0cfbea34
Reviewed-by: Shawn Rutledge <shawn.rutledge@digia.com>

2 files changed, 24 insertions, 2 deletions

diff --git a/src/corelib/kernel/qmetatype.cpp b/src/corelib/kernel/qmetatype.cpp
index aae772ffeb..f9092b0a32 100644
--- a/src/corelib/kernel/qmetatype.cpp
+++ b/src/corelib/kernel/qmetatype.cpp
@@ -282,7 +282,7 @@ struct DefinedTypesFilter {
     \value NeedsDestruction This type has a non-trivial destructor. If the flag is not set calls to the destructor are not necessary before discarding objects.
     \value MovableType An instance of a type having this attribute can be safely moved by memcpy.
     \omitvalue SharedPointerToQObject
-    \omitvalue IsEnumeration
+    \value IsEnumeration This type is an enumeration
     \value PointerToQObject This type is a pointer to a derived of QObject
     \omitvalue WeakPointerToQObject
     \omitvalue TrackingPointerToQObject
@@ -376,6 +376,10 @@ struct DefinedTypesFilter {
     QMetaObject.  This can be used to retrieve QMetaMethod and QMetaProperty and use them on a
     pointer of this type. (given by QVariant::data for example)
 
+    If the type is an enumaration, flags contains QMetaType::IsEnumeration, and this function
+    returns the QMetaObject of the enclosing object if the enum was registered as a Q_ENUM or 0
+    otherwise
+
     \sa QMetaType::metaObjectForType(), QMetaType::flags()
 */
 
diff --git a/src/corelib/kernel/qmetatype.h b/src/corelib/kernel/qmetatype.h
index 2ff695b833..5ca44f9440 100644
--- a/src/corelib/kernel/qmetatype.h
+++ b/src/corelib/kernel/qmetatype.h
@@ -1363,12 +1363,25 @@ namespace QtPrivate
         enum { Value = sizeof(checkType(static_cast<T*>(0))) == sizeof(void*)  };
     };
 
+    char qt_getEnumMetaObject(...);
+    char qt_getEnumMetaObject(); // Workaround bugs in MSVC.
+
+    template<typename T>
+    struct IsQEnumHelper {
+        static const T &declval();
+        enum { Value = sizeof(qt_getEnumMetaObject(declval())) == sizeof(QMetaObject*) };
+    };
+
     template<typename T, typename Enable = void>
     struct MetaObjectForType
     {
         static inline const QMetaObject *value() { return 0; }
     };
-
+    template<>
+    struct MetaObjectForType<void>
+    {
+        static inline const QMetaObject *value() { return Q_NULLPTR; }
+    };
     template<typename T>
     struct MetaObjectForType<T*, typename QEnableIf<IsPointerToTypeDerivedFromQObject<T*>::Value>::Type>
     {
@@ -1379,6 +1392,11 @@ namespace QtPrivate
     {
         static inline const QMetaObject *value() { return &T::staticMetaObject; }
     };
+    template<typename T>
+    struct MetaObjectForType<T, typename QEnableIf<IsQEnumHelper<T>::Value>::Type >
+    {
+        static inline const QMetaObject *value() { return qt_getEnumMetaObject(T()); }
+    };
 
     template<typename T>
     struct IsSharedPointerToTypeDerivedFromQObject