Optimize QListViewPrivate::draggablePaintPairs()

Instead of converting a QVector to a QList to a QSet just to
be able to look up some indexes, take the original QVector,
sort it, and use std::binary_search().

Change-Id: If56e9371972b9aaebb033a8a499be306163266e2
Reviewed-by: Olivier Goffart (Woboq GmbH) <ogoffart@woboq.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/src/widgets/itemviews/qlistview.cpp b/src/widgets/itemviews/qlistview.cpp
index 7cd8e890db..985b347bbc 100644
--- a/src/widgets/itemviews/qlistview.cpp
+++ b/src/widgets/itemviews/qlistview.cpp
@@ -650,9 +650,10 @@ QItemViewPaintPairs QListViewPrivate::draggablePaintPairs(const QModelIndexList
     QRect &rect = *r;
     const QRect viewportRect = viewport->rect();
     QItemViewPaintPairs ret;
-    const QSet<QModelIndex> visibleIndexes = intersectingSet(viewportRect.translated(q->horizontalOffset(), q->verticalOffset())).toList().toSet();
+    QVector<QModelIndex> visibleIndexes = intersectingSet(viewportRect.translated(q->horizontalOffset(), q->verticalOffset()));
+    std::sort(visibleIndexes.begin(), visibleIndexes.end());
     for (const auto &index : indexes) {
-        if (visibleIndexes.contains(index)) {
+        if (std::binary_search(visibleIndexes.cbegin(), visibleIndexes.cend(), index)) {
             const QRect current = q->visualRect(index);
             QItemViewPaintPair p = { current, index };
             ret += p;