QtWidgets: replace some index-based for loops with C++11 range-for

This needs to be handled a bit carefully, because Qt containers
will detach upon being iteratoed over using range-for.

In the cases of this patch, that cannot happen, because all
containers are marked as const (either by this patch or before).

Separate patches will deal with other situations.

Apart from being more readable, range-for loops are also the
most efficient for loop.

This patch shaves almost 2K of text size off an optimized Linux
AMD64 GCC 4.9 build.

Change-Id: I53810c7b25420b4fd449d20c90c07503c5e76a66
Reviewed-by: Edward Welbourne <edward.welbourne@theqtcompany.com>
Reviewed-by: Lars Knoll <lars.knoll@theqtcompany.com>

1 files changed, 8 insertions, 10 deletions

diff --git a/src/widgets/itemviews/qlistview.cpp b/src/widgets/itemviews/qlistview.cpp
index 2dbbd211c0..7cd8e890db 100644
--- a/src/widgets/itemviews/qlistview.cpp
+++ b/src/widgets/itemviews/qlistview.cpp
@@ -651,8 +651,7 @@ QItemViewPaintPairs QListViewPrivate::draggablePaintPairs(const QModelIndexList
     const QRect viewportRect = viewport->rect();
     QItemViewPaintPairs ret;
     const QSet<QModelIndex> visibleIndexes = intersectingSet(viewportRect.translated(q->horizontalOffset(), q->verticalOffset())).toList().toSet();
-    for (int i = 0; i < indexes.count(); ++i) {
-        const QModelIndex &index = indexes.at(i);
+    for (const auto &index : indexes) {
         if (visibleIndexes.contains(index)) {
             const QRect current = q->visualRect(index);
             QItemViewPaintPair p = { current, index };
@@ -1398,16 +1397,16 @@ QRegion QListView::visualRegionForSelection(const QItemSelection &selection) con
     int c = d->column;
     QRegion selectionRegion;
     const QRect &viewportRect = d->viewport->rect();
-    for (int i = 0; i < selection.count(); ++i) {
-        if (!selection.at(i).isValid())
+    for (const auto &elem : selection) {
+        if (!elem.isValid())
             continue;
-        QModelIndex parent = selection.at(i).topLeft().parent();
+        QModelIndex parent = elem.topLeft().parent();
         //we only display the children of the root in a listview
         //we're not interested in the other model indexes
         if (parent != d->root)
             continue;
-        int t = selection.at(i).topLeft().row();
-        int b = selection.at(i).bottomRight().row();
+        int t = elem.topLeft().row();
+        int b = elem.bottomRight().row();
         if (d->viewMode == IconMode || d->isWrapping()) { // in non-static mode, we have to go through all selected items
             for (int r = t; r <= b; ++r) {
                 const QRect &rect = visualRect(d->model->index(r, c, parent));
@@ -2771,9 +2770,8 @@ bool QIconModeViewBase::filterDropEvent(QDropEvent *e)
     }
     QPoint start = dd->pressedPosition;
     QPoint delta = (dd->movement == QListView::Snap ? snapToGrid(end) - snapToGrid(start) : end - start);
-    QList<QModelIndex> indexes = dd->selectionModel->selectedIndexes();
-    for (int i = 0; i < indexes.count(); ++i) {
-        QModelIndex index = indexes.at(i);
+    const QList<QModelIndex> indexes = dd->selectionModel->selectedIndexes();
+    for (const auto &index : indexes) {
         QRect rect = dd->rectForIndex(index);
         viewport()->update(dd->mapToViewport(rect, false));
         QPoint dest = rect.topLeft() + delta;