Make QML composite types inherit enums

Problem: in Qt Quick Controls 2, enums declared in the abstract
C++ base types were not accessible with the concrete QML type name,
but had to be referenced using the base type name:

    Slider {
        snapMode: AbstractSlider.SnapOnRelease
    }

Solution: this change resolves the C++ base type and creates the
missing link between the composite type and its base type's meta-
object. This allows referencing enums using the concrete/composite
QML type name:

    Slider {
        snapMode: Slider.SnapOnRelease
    }

Change-Id: Icefdec91b012b12728367fd54b4d16796233ee12
Task-number: QTBUG-43582
Reviewed-by: Simon Hausmann <simon.hausmann@theqtcompany.com>

1 files changed, 5 insertions, 3 deletions

diff --git a/src/qml/qml/qqmlmetatype_p.h b/src/qml/qml/qqmlmetatype_p.h
index 61a6567f1d..08f19bcf09 100644
--- a/src/qml/qml/qqmlmetatype_p.h
+++ b/src/qml/qml/qqmlmetatype_p.h
@@ -57,6 +57,7 @@ QT_BEGIN_NAMESPACE
 
 class QQmlType;
 class QQmlEngine;
+class QQmlEnginePrivate;
 class QQmlCustomParser;
 class QQmlTypePrivate;
 class QQmlTypeModule;
@@ -204,11 +205,12 @@ public:
 
     QUrl sourceUrl() const;
 
-    int enumValue(const QHashedStringRef &, bool *ok) const;
-    int enumValue(const QHashedCStringRef &, bool *ok) const;
-    int enumValue(const QV4::String *, bool *ok) const;
+    int enumValue(QQmlEnginePrivate *engine, const QHashedStringRef &, bool *ok) const;
+    int enumValue(QQmlEnginePrivate *engine, const QHashedCStringRef &, bool *ok) const;
+    int enumValue(QQmlEnginePrivate *engine, const QV4::String *, bool *ok) const;
 private:
     QQmlType *superType() const;
+    int resolveCompositeEnumValue(QQmlEnginePrivate *engine, const QString &name, bool *ok) const;
     friend class QQmlTypePrivate;
     friend struct QQmlMetaTypeData;