Looping over QList::contains() constitutes O(N²) behavior,
the more so as this QList is horribly inefficient since
WritingSystem is not a Q_MOVABLE_TYPE.
Since the range of possible unique values in the result
is severly limited (by virtue of being enumerated values),
use a bitmask to remember which WritingSystems were
encountered, then, after releaseing the mutex again, use
that bitmask to populate the QList.
Change-Id: I1d12eb487513ec17faa6f38942f8b681819dc0e8
Reviewed-by: Adam Majer <adamm@zombino.com>
Reviewed-by: Konstantin Ritt <ritt.ks@gmail.com>
Reviewed-by: Lars Knoll <lars.knoll@theqtcompany.com>
452ece9c02