Delete the QSlotObject when disconnect()ing

When disconnect()ing through a QMetaObject::Connection,  if the
QObjectPrivate::Connection contains a slot object, deref it, so
that it will be destroyed before the next run of cleanConnectionList.

Previously, a copy of the functor passed to connect() was kept until
QObjectPrivate::cleanConnectionLists was called (by adding a new signal,
or the sender was destroyed), even after a successful call to
disconnect(). That is, we were keeping that copy allocated without
any good reason.

Change-Id: Ie6074ea797df1611cb995dec07c5b5a742360833
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/src/corelib/kernel/qobject.cpp b/src/corelib/kernel/qobject.cpp
index 20c634ad78..9091b5579e 100644
--- a/src/corelib/kernel/qobject.cpp
+++ b/src/corelib/kernel/qobject.cpp
@@ -4294,6 +4294,12 @@ bool QObject::disconnect(const QMetaObject::Connection &connection)
         c->next->prev = c->prev;
     c->receiver = 0;
 
+    // destroy the QSlotObject, if possible
+    if (c->isSlotObject) {
+        c->slotObj->destroyIfLastRef();
+        c->isSlotObject = false;
+    }
+
     const_cast<QMetaObject::Connection &>(connection).d_ptr = 0;
     c->deref(); // has been removed from the QMetaObject::Connection object