QIdentityProxyModel: add setHandleSourceLayoutChanges(bool)

Some sub-classes have special handling of source model layout changes
(abbreviated as SMLC from here on out), they relied on disconnecting the
connections to the _q_*layout* slots in the private class using the SLOT
macro. This isn't possible any more after recent changes (and the method
were renamed to remove _q_ prefix).

Sub-classes resorting to using private API is a clear sign some
functionality is missing from the public API, so a cleaner solution for
this issue is adding this setter which enables sub-classes to tell
QIdentityProxyModel to leave handling of the SMLC to them. Thanks to
David Faure for the idea/solution.

[ChangeLog][QtCore][QIdentityProxyModel] Added
setHandleSourceLayoutChanges(bool) method to allow sub-classes to
indicate to QIdentityProxyModel that they will handle source model
layout changes on their own. Also added a getter,
isHandleSourceLayoutChanges().

Change-Id: I1de79dd693ce32a6e2df9a7c81dd4abdc5f00248
Reviewed-by: Axel Spoerl <axel.spoerl@qt.io>

1 files changed, 35 insertions, 0 deletions

diff --git a/tests/auto/corelib/itemmodels/qidentityproxymodel/tst_qidentityproxymodel.cpp b/tests/auto/corelib/itemmodels/qidentityproxymodel/tst_qidentityproxymodel.cpp
index b1de23d619..467910ef48 100644
--- a/tests/auto/corelib/itemmodels/qidentityproxymodel/tst_qidentityproxymodel.cpp
+++ b/tests/auto/corelib/itemmodels/qidentityproxymodel/tst_qidentityproxymodel.cpp
@@ -27,6 +27,16 @@ public:
         const QModelIndex idx = index(0, 0, QModelIndex());
         Q_EMIT dataChanged(idx, idx, QList<int>() << 1);
     }
+
+    // Workaround QObject::isSignalConnected() being a protected method
+    bool isConnected(const QMetaMethod &m) const { return isSignalConnected(m); }
+};
+
+class IdentityProxyModel : public QIdentityProxyModel
+{
+public:
+    // The name has to be different than the method from the base class
+    void setHandleSLC(bool b) { setHandleSourceLayoutChanges(b); }
 };
 
 class tst_QIdentityProxyModel : public QObject
@@ -53,6 +63,9 @@ private slots:
 
     void persistIndexOnLayoutChange();
     void createPersistentOnLayoutAboutToBeChanged();
+
+    void testSetHandleLayoutChanges();
+
 protected:
     void verifyIdentity(QAbstractItemModel *model, const QModelIndex &parent = QModelIndex());
 
@@ -513,5 +526,27 @@ void tst_QIdentityProxyModel::createPersistentOnLayoutAboutToBeChanged() // QTBU
     QCOMPARE(layoutChangedSpy.size(), 1);
 }
 
+void tst_QIdentityProxyModel::testSetHandleLayoutChanges()
+{
+    const std::array layoutSignals = {
+        QMetaMethod::fromSignal(&QAbstractItemModel::layoutChanged),
+        QMetaMethod::fromSignal(&QAbstractItemModel::layoutAboutToBeChanged),
+    };
+
+    DataChangedModel model;
+    IdentityProxyModel proxy;
+    proxy.setSourceModel(&model);
+    for (const auto &m : layoutSignals)
+        QVERIFY(model.isConnected(m)); // Connected by default
+
+    proxy.setSourceModel(nullptr);
+
+    // Disable handling (connecting to layotu signals) of source model layout changes
+    proxy.setHandleSLC(false);
+    proxy.setSourceModel(&model);
+    for (const auto &m : layoutSignals)
+        QVERIFY(!model.isConnected(m));
+}
+
 QTEST_MAIN(tst_QIdentityProxyModel)
 #include "tst_qidentityproxymodel.moc"