Quick: fix expensive iteration over QHash::keys() and QMap::keys()

Change-Id: I21c48214bfddde01f71710705fe01418818a6581
Reviewed-by: Lars Knoll <lars.knoll@theqtcompany.com>

1 files changed, 5 insertions, 1 deletions

diff --git a/src/quick/items/qquickmultipointtoucharea.cpp b/src/quick/items/qquickmultipointtoucharea.cpp
index 9e658cc668..e3a8fe3cc6 100644
--- a/src/quick/items/qquickmultipointtoucharea.cpp
+++ b/src/quick/items/qquickmultipointtoucharea.cpp
@@ -470,7 +470,11 @@ void QQuickMultiPointTouchArea::grabGesture()
     grabMouse();
     setKeepMouseGrab(true);
 
-    grabTouchPoints(_touchPoints.keys().toVector());
+    QVector<int> ids;
+    ids.reserve(_touchPoints.size());
+    for (auto it = _touchPoints.keyBegin(), end = _touchPoints.keyEnd(); it != end; ++it)
+        ids.append(*it);
+    grabTouchPoints(ids);
     setKeepTouchGrab(true);
 }