Introduce QMetaObject::metaType

This function returns the metatype corresponding to the metaobject, or
an invalid metatype for namespaces.

This works as follows: First we increment the metaobject revision for
new metaobjects. Metaobjects with older revisions are handled by doing a
lookup by name. That fallback is also used for dynamic metaobjects (from
QtDBUS and those created by QMetaObjectBuilder).
For new metaobjects, we store the metatype in its metatype array, behind
the property metatypes. This avoids any changes to the property and
method metatype extraction logic: For properties, the metatype access
does not change, as the new metatype is after their metatypes. For
method metatypes, we already have an indirection layer (using offsets),
so by adjusting those offsets by one, the same logic keeps working.

To distinguish between namespaces and dynamic metaobjects, namespaces
store the metatypeinterface pointer for void in the metatype array,
whereas dynamic metaobjects store a nullptr.

One nice additional benefit is that this simplifies the generator logic
in moc, as the metatype array is now never empty.

Task-number: QTBUG-92077
Change-Id: Id3f920f28553f12032a71a1a87dad29e5374dbe7
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>
Reviewed-by: Andrei Golubev <andrei.golubev@qt.io>

1 files changed, 11 insertions, 0 deletions

diff --git a/tests/auto/corelib/kernel/qmetaobject/tst_qmetaobject.cpp b/tests/auto/corelib/kernel/qmetaobject/tst_qmetaobject.cpp
index 86501b74ea..968ccee043 100644
--- a/tests/auto/corelib/kernel/qmetaobject/tst_qmetaobject.cpp
+++ b/tests/auto/corelib/kernel/qmetaobject/tst_qmetaobject.cpp
@@ -315,6 +315,8 @@ private slots:
     void propertyConstant();
     void propertyFinal();
 
+    void metaType();
+
     void stdSet();
     void classInfo();
 
@@ -1612,6 +1614,15 @@ void tst_QMetaObject::propertyFinal()
     QVERIFY(!prop.isFinal());
 }
 
+void tst_QMetaObject::metaType()
+{
+    QCOMPARE(QObject::staticMetaObject.metaType(), QMetaType::fromType<QObject>());
+    QCOMPARE(MyGadget::staticMetaObject.metaType(), QMetaType::fromType<MyGadget>());
+    QCOMPARE(QAbstractProxyModel::staticMetaObject.metaType(), QMetaType::fromType<QAbstractProxyModel>());
+    auto qtNameSpaceMetaType = Qt::staticMetaObject.metaType();
+    QVERIFY2(!qtNameSpaceMetaType.isValid(), qtNameSpaceMetaType.name());
+}
+
 class ClassInfoTestObjectA : public QObject
 {
     Q_OBJECT