QBindable: Improve read-only support

If we create a QBindable from a const property, we should obtain a
read-only interface. Besides implementing this feature, this patch adds
a isReadOnly method to Q(Untyped)Bindable which can be used to check
whether one can modify the property via the bindable interface.

Task-number: QTBUG-89505
Task-number: QTBUG-89469
Change-Id: Ic36949a5b84c5119e0060ed0a1cf4ac94a66f341
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

1 files changed, 8 insertions, 0 deletions

diff --git a/tests/auto/corelib/kernel/qproperty/tst_qproperty.cpp b/tests/auto/corelib/kernel/qproperty/tst_qproperty.cpp
index 4559587afd..7de6458406 100644
--- a/tests/auto/corelib/kernel/qproperty/tst_qproperty.cpp
+++ b/tests/auto/corelib/kernel/qproperty/tst_qproperty.cpp
@@ -1048,6 +1048,7 @@ public:
     }
 
     QBindable<int> bindableFoo() { return QBindable<int>(&fooData); }
+    const QBindable<int> bindableFoo() const { return QBindable<int>(&fooData); }
     QBindable<int> bindableBar() { return QBindable<int>(&barData); }
     QBindable<int> bindableRead() { return QBindable<int>(&readData); }
     QBindable<int> bindableComputed() { return QBindable<int>(&computedData); }
@@ -1068,7 +1069,14 @@ public:
 
 void tst_QProperty::testNewStuff()
 {
+    MyQObject testReadOnly;
+    testReadOnly.bindableFoo().setBinding([](){return 42;});
+    auto bindable = const_cast<const MyQObject&>(testReadOnly).bindableFoo();
+    QVERIFY(bindable.hasBinding());
+    QVERIFY(bindable.isReadOnly());
+
     MyQObject object;
+    QVERIFY(!object.bindableFoo().isReadOnly());
     QObject::connect(&object, &MyQObject::fooChanged, &object, &MyQObject::fooHasChanged);
     QObject::connect(&object, &MyQObject::barChanged, &object, &MyQObject::barHasChanged);