Add support for binding directly to QProperty instances

Avoid going through externally managed bindings and instead allocate a
more lightweight property binding. It's basically a
QQmlJavaScriptExpression and one pointer plus the overhead of
QPropertyBindingPrivate.

Change-Id: I1530330926d351b61f2b3bbad39301c628a8bef1
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

1 files changed, 17 insertions, 0 deletions

diff --git a/tests/auto/qml/qqmlecmascript/tst_qqmlecmascript.cpp b/tests/auto/qml/qqmlecmascript/tst_qqmlecmascript.cpp
index b3e4296a13..fbb344f9a0 100644
--- a/tests/auto/qml/qqmlecmascript/tst_qqmlecmascript.cpp
+++ b/tests/auto/qml/qqmlecmascript/tst_qqmlecmascript.cpp
@@ -381,6 +381,7 @@ private slots:
     void getThisObject();
     void semicolonAfterProperty();
     void hugeStack();
+    void bindingOnQProperty();
 
     void gcCrashRegressionTest();
 
@@ -9281,6 +9282,22 @@ void tst_qqmlecmascript::gcCrashRegressionTest()
     QCOMPARE(process.exitCode(), 0);
 }
 
+void tst_qqmlecmascript::bindingOnQProperty()
+{
+    QQmlEngine engine;
+    QQmlComponent component(&engine, testFileUrl("bindingOnQProperty.qml"));
+    QVERIFY2(component.isReady(), qPrintable(component.errorString()));
+    QScopedPointer<QObject> test(component.create());
+    test->setProperty("externalValue", 42);
+    QCOMPARE(test->property("value").toInt(), 42);
+    test->setProperty("externalValue", 100);
+    QCOMPARE(test->property("value").toInt(), 100);
+
+    QVERIFY(qobject_cast<ClassWithQProperty*>(test.data()));
+    QProperty<int> &qprop = static_cast<ClassWithQProperty*>(test.data())->value;
+    QVERIFY(qprop.hasBinding());
+}
+
 QTEST_MAIN(tst_qqmlecmascript)
 
 #include "tst_qqmlecmascript.moc"