QMacStyle: replace a QSet<QPointer> with QVector<QPointer>

Holding a mutable item in a QSet violates QSet invariants, namely that in
bucket N, all items have hash % size == N. If a value gets reset to
nullptr by external means, that invariant no longer holds. The code works
by pure luck.

Replace the set with a vector, which doesn't care whether elements change
under the hood, and will also outperform the typical QSet use due to
better locality of reference.

Change-Id: Ied7940e82525fd0da9f74dfb0bc36a320b45d172
Reviewed-by: Olivier Goffart (Woboq GmbH) <ogoffart@woboq.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/src/widgets/styles/qmacstyle_mac_p_p.h b/src/widgets/styles/qmacstyle_mac_p_p.h
index b09e81d595..33818568ec 100644
--- a/src/widgets/styles/qmacstyle_mac_p_p.h
+++ b/src/widgets/styles/qmacstyle_mac_p_p.h
@@ -86,7 +86,7 @@
 #include <qdatetimeedit.h>
 #include <qmath.h>
 #include <qpair.h>
-#include <qset.h>
+#include <qvector.h>
 #include <QtWidgets/qgraphicsproxywidget.h>
 #include <QtWidgets/qgraphicsview.h>
 
@@ -213,7 +213,7 @@ public:
     mutable QPointer<QObject> pressedButton;
     mutable QPointer<QObject> defaultButton;
     mutable QPointer<QObject> autoDefaultButton;
-    static  QSet<QPointer<QObject> > scrollBars;
+    static  QVector<QPointer<QObject> > scrollBars;
 
     struct ButtonState {
         int frame;