Simplify the safeguarding logic in notify()

The logic in notify() was doing quite a bit more work than
it needed to. By inserting a dummy node after the current one instead of
replacing it, we can avoid half of the data shuffling that has been
happening and also don't need a back pointer when executing the
notification.

Also avoid calling a semi expensive destructor of QPropertyObserver.

Reduces the overhead of notify() by ~30%.

Change-Id: I7ce16bcf9cd9c4368c18bf875fc959223452fd4f
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
(cherry picked from commit e8ef871e3522f340b4efe32382af7e35ef908665)
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

0 files changed, 0 insertions, 0 deletions