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, 1 insertions, 0 deletions

diff --git a/src/corelib/itemmodels/qidentityproxymodel_p.h b/src/corelib/itemmodels/qidentityproxymodel_p.h
index d36fa426da..78e1f5316c 100644
--- a/src/corelib/itemmodels/qidentityproxymodel_p.h
+++ b/src/corelib/itemmodels/qidentityproxymodel_p.h
@@ -63,6 +63,7 @@ public:
     void sourceModelReset();
 
 private:
+    bool m_handleLayoutChanges = true;
     QVarLengthArray<QMetaObject::Connection, 18> m_sourceModelConnections;
 };