Support querying indirect extensions for a given object

Introduce a private version of qmlExtendedObject() that returns an
index-based extension (where 0 represents an extension on the leaf type
and N represents a (N - 1)th base type's extension)

Teach QQmlProxyMetaObject to distinguish different extension proxies.
Its custom metaCall can now query up to 128 extensions (should be enough
for the user needs)

Change-Id: I5520a1e84501f1f9fe6a8e77d8269009a12c255c
Reviewed-by: Maximilian Goldstein <max.goldstein@qt.io>
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

2 files changed, 87 insertions, 0 deletions

diff --git a/tests/auto/qml/qqmllanguage/testtypes.h b/tests/auto/qml/qqmllanguage/testtypes.h
index 8efccbc0fb..ca42ae02bc 100644
--- a/tests/auto/qml/qqmllanguage/testtypes.h
+++ b/tests/auto/qml/qqmllanguage/testtypes.h
@@ -1851,6 +1851,35 @@ public:
     ExtendedInParentByIndirect(QObject *parent = nullptr) : ExtendedByIndirect(parent) { }
 };
 
+class MultiExtensionThreeExtensions : public MultiExtension
+{
+    Q_OBJECT
+    QML_ELEMENT
+    QML_EXTENDED(Extension)
+public:
+    MultiExtensionThreeExtensions(QObject *parent = nullptr) : MultiExtension(parent) { }
+};
+
+class MultiExtensionWithoutExtension : public MultiExtension
+{
+    Q_OBJECT
+    QML_ANONYMOUS
+public:
+    MultiExtensionWithoutExtension(QObject *parent = nullptr) : MultiExtension(parent) { }
+};
+
+class MultiExtensionWithExtensionInBaseBase : public MultiExtensionWithoutExtension
+{
+    Q_OBJECT
+    QML_ELEMENT
+    QML_EXTENDED(Extension)
+public:
+    MultiExtensionWithExtensionInBaseBase(QObject *parent = nullptr)
+        : MultiExtensionWithoutExtension(parent)
+    {
+    }
+};
+
 class StringSignaler : public QObject
 {
     Q_OBJECT
diff --git a/tests/auto/qml/qqmllanguage/tst_qqmllanguage.cpp b/tests/auto/qml/qqmllanguage/tst_qqmllanguage.cpp
index 1e3f06a9e9..bfcd146b10 100644
--- a/tests/auto/qml/qqmllanguage/tst_qqmllanguage.cpp
+++ b/tests/auto/qml/qqmllanguage/tst_qqmllanguage.cpp
@@ -365,6 +365,7 @@ private slots:
     void qtbug_86482();
 
     void multiExtension();
+    void multiExtensionExtra();
     void multiExtensionIndirect();
     void extensionSpecial();
     void invalidInlineComponent();
@@ -6395,6 +6396,63 @@ void tst_qqmllanguage::multiExtension()
     QCOMPARE(o->property("d").toInt(), 22);
     QCOMPARE(o->property("f").toInt(), 31);
     QCOMPARE(o->property("g").toInt(), 44); // NB: taken from the type, not from the extension!
+
+    QObject *extension = qmlExtendedObject(o.get());
+    QVERIFY(extension != nullptr);
+    QVERIFY(qobject_cast<ExtensionB *>(extension) != nullptr);
+
+    QCOMPARE(QQmlPrivate::qmlExtendedObject(o.get(), 0), extension);
+    QObject *baseTypeExtension = QQmlPrivate::qmlExtendedObject(o.get(), 1);
+    QVERIFY(baseTypeExtension);
+    QVERIFY(qobject_cast<ExtensionA *>(baseTypeExtension) != nullptr);
+}
+
+void tst_qqmllanguage::multiExtensionExtra()
+{
+    QQmlEngine engine;
+    {
+        QQmlComponent c(&engine);
+        c.setData("import StaticTest\nMultiExtensionThreeExtensions {}", QUrl());
+        QVERIFY2(c.isReady(), qPrintable(c.errorString()));
+        QScopedPointer<QObject> o(c.create());
+
+        QObject *extension = qmlExtendedObject(o.get());
+        QVERIFY(extension != nullptr);
+        QVERIFY(qobject_cast<Extension *>(extension) != nullptr);
+
+        QCOMPARE(QQmlPrivate::qmlExtendedObject(o.get(), 0), extension);
+        QObject *baseTypeExtension = QQmlPrivate::qmlExtendedObject(o.get(), 1);
+        QVERIFY(baseTypeExtension);
+        QVERIFY(qobject_cast<ExtensionB *>(baseTypeExtension) != nullptr);
+        QObject *baseBaseTypeExtension = QQmlPrivate::qmlExtendedObject(o.get(), 2);
+        QVERIFY(baseBaseTypeExtension);
+        QVERIFY(qobject_cast<ExtensionA *>(baseBaseTypeExtension) != nullptr);
+    }
+
+    {
+        QQmlComponent c(&engine);
+        c.setData("import StaticTest\nMultiExtensionWithExtensionInBaseBase {}", QUrl());
+        QVERIFY2(c.isReady(), qPrintable(c.errorString()));
+        QScopedPointer<QObject> o(c.create());
+
+        QObject *extension = qmlExtendedObject(o.get());
+        QVERIFY(extension != nullptr);
+        QVERIFY(qobject_cast<Extension *>(extension) != nullptr);
+
+        QCOMPARE(QQmlPrivate::qmlExtendedObject(o.get(), 0), extension);
+
+        QObject *pseudoExtension = QQmlPrivate::qmlExtendedObject(o.get(), 1);
+        QVERIFY(pseudoExtension);
+        QVERIFY(qobject_cast<ExtensionB *>(pseudoExtension) != nullptr);
+
+        QObject *baseBaseTypeExtension = QQmlPrivate::qmlExtendedObject(o.get(), 2);
+        QVERIFY(baseBaseTypeExtension);
+        QVERIFY(qobject_cast<ExtensionB *>(baseBaseTypeExtension) != nullptr);
+
+        QObject *baseBaseBaseTypeExtension = QQmlPrivate::qmlExtendedObject(o.get(), 3);
+        QVERIFY(baseBaseBaseTypeExtension);
+        QVERIFY(qobject_cast<ExtensionA *>(baseBaseBaseTypeExtension) != nullptr);
+    }
 }
 
 void tst_qqmllanguage::multiExtensionIndirect()