QtWidgets: replace uses of inefficient QList<QPair>s with QVectors

These QPairs are larger than a void*, so holding them in QLists
is needlessly inefficient. Worse, the code could come to depend
on the fragile property of (inefficient) QLists that references
to elements therein never are invalidated.

Fix by holding them in QVector instead.

Change-Id: I3c205f5326cfd96482563078bdca1747d718457f
Reviewed-by: Olivier Goffart (Woboq GmbH) <ogoffart@woboq.com>

2 files changed, 5 insertions, 5 deletions

diff --git a/src/widgets/graphicsview/qgraph_p.h b/src/widgets/graphicsview/qgraph_p.h
index 34c6a8c3c5..14f7122d5c 100644
--- a/src/widgets/graphicsview/qgraph_p.h
+++ b/src/widgets/graphicsview/qgraph_p.h
@@ -211,8 +211,8 @@ public:
         return setOfVertices;
     }
 
-    QList<QPair<Vertex*, Vertex*> > connections() const {
-        QList<QPair<Vertex*, Vertex*> > conns;
+    QVector<QPair<Vertex*, Vertex*> > connections() const {
+        QVector<QPair<Vertex*, Vertex*> > conns;
         for (const_iterator it = constBegin(); it != constEnd(); ++it) {
             Vertex *from = it.from();
             Vertex *to = it.to();
diff --git a/src/widgets/graphicsview/qgraphicsanchorlayout_p.cpp b/src/widgets/graphicsview/qgraphicsanchorlayout_p.cpp
index b5865ec9c9..1e5aea9688 100644
--- a/src/widgets/graphicsview/qgraphicsanchorlayout_p.cpp
+++ b/src/widgets/graphicsview/qgraphicsanchorlayout_p.cpp
@@ -1266,7 +1266,7 @@ void QGraphicsAnchorLayoutPrivate::restoreSimplifiedGraph(Orientation orientatio
 
     // Restore anchor simplification
     Graph<AnchorVertex, AnchorData> &g = graph[orientation];
-    QList<QPair<AnchorVertex*, AnchorVertex*> > connections = g.connections();
+    QVector<QPair<AnchorVertex*, AnchorVertex*> > connections = g.connections();
     for (int i = 0; i < connections.count(); ++i) {
         AnchorVertex *v1 = connections.at(i).first;
         AnchorVertex *v2 = connections.at(i).second;
@@ -2295,7 +2295,7 @@ bool QGraphicsAnchorLayoutPrivate::calculateNonTrunk(const QList<QSimplexConstra
 void QGraphicsAnchorLayoutPrivate::refreshAllSizeHints(Orientation orientation)
 {
     Graph<AnchorVertex, AnchorData> &g = graph[orientation];
-    QList<QPair<AnchorVertex *, AnchorVertex *> > vertices = g.connections();
+    QVector<QPair<AnchorVertex *, AnchorVertex *> > vertices = g.connections();
 
     QLayoutStyleInfo styleInf = styleInfo();
     for (int i = 0; i < vertices.count(); ++i) {
@@ -2388,7 +2388,7 @@ void QGraphicsAnchorLayoutPrivate::constraintsFromPaths(Orientation orientation)
 void QGraphicsAnchorLayoutPrivate::updateAnchorSizes(Orientation orientation)
 {
     Graph<AnchorVertex, AnchorData> &g = graph[orientation];
-    const QList<QPair<AnchorVertex *, AnchorVertex *> > &vertices = g.connections();
+    const QVector<QPair<AnchorVertex *, AnchorVertex *> > &vertices = g.connections();
 
     for (int i = 0; i < vertices.count(); ++i) {
         AnchorData *ad = g.edgeData(vertices.at(i).first, vertices.at(i).second);