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, 27 insertions, 3 deletions

diff --git a/src/qml/qml/qqmlmetatype.cpp b/src/qml/qml/qqmlmetatype.cpp
index f0debb8e59..b173bc8bec 100644
--- a/src/qml/qml/qqmlmetatype.cpp
+++ b/src/qml/qml/qqmlmetatype.cpp
@@ -38,6 +38,7 @@
 #include <private/qqmlcustomparser_p.h>
 #include <private/qhashedstring_p.h>
 #include <private/qqmlimport_p.h>
+#include <private/qqmlcompiler_p.h>
 
 #include <QtCore/qdebug.h>
 #include <QtCore/qstringlist.h>
@@ -473,6 +474,23 @@ QQmlType *QQmlType::superType() const
     return d->superType;
 }
 
+int QQmlType::resolveCompositeEnumValue(QQmlEnginePrivate *engine, const QString &name, bool *ok) const
+{
+    Q_ASSERT(isComposite());
+    *ok = false;
+    if (!engine)
+        return -1;
+    QQmlTypeData *td = engine->typeLoader.getType(sourceUrl());
+    if (!td || !td->isComplete())
+        return -1;
+    QQmlCompiledData *cd = td->compiledData();
+    const QMetaObject *mo = cd->rootPropertyCache->firstCppMetaObject();
+    QQmlType *type = QQmlMetaType::qmlType(mo);
+    if (!type)
+        return -1;
+    return type->enumValue(engine, name, ok);
+}
+
 static void clone(QMetaObjectBuilder &builder, const QMetaObject *mo,
                   const QMetaObject *ignoreStart, const QMetaObject *ignoreEnd)
 {
@@ -907,9 +925,11 @@ QUrl QQmlType::sourceUrl() const
         return QUrl();
 }
 
-int QQmlType::enumValue(const QHashedStringRef &name, bool *ok) const
+int QQmlType::enumValue(QQmlEnginePrivate *engine, const QHashedStringRef &name, bool *ok) const
 {
     Q_ASSERT(ok);
+    if (isComposite())
+        return resolveCompositeEnumValue(engine, name.toString(), ok);
     *ok = true;
 
     d->initEnums();
@@ -922,9 +942,11 @@ int QQmlType::enumValue(const QHashedStringRef &name, bool *ok) const
     return -1;
 }
 
-int QQmlType::enumValue(const QHashedCStringRef &name, bool *ok) const
+int QQmlType::enumValue(QQmlEnginePrivate *engine, const QHashedCStringRef &name, bool *ok) const
 {
     Q_ASSERT(ok);
+    if (isComposite())
+        return resolveCompositeEnumValue(engine, name.toUtf16(), ok);
     *ok = true;
 
     d->initEnums();
@@ -937,9 +959,11 @@ int QQmlType::enumValue(const QHashedCStringRef &name, bool *ok) const
     return -1;
 }
 
-int QQmlType::enumValue(const QV4::String *name, bool *ok) const
+int QQmlType::enumValue(QQmlEnginePrivate *engine, const QV4::String *name, bool *ok) const
 {
     Q_ASSERT(ok);
+    if (isComposite())
+        return resolveCompositeEnumValue(engine, name->toQString(), ok);
     *ok = true;
 
     d->initEnums();