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

This needs to be handled a bit carefully, because Qt containers
will detach upon being iterated 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.

Range-for loops are much more efficient than foreach loops.

This patch shaves almost 3K of text size off an optimized Linux
AMD64 GCC 4.9 build.

Change-Id: I7b1d41db4d9b5db8b515cb75686dc5135177da68
Reviewed-by: Lars Knoll <lars.knoll@theqtcompany.com>

6 files changed, 34 insertions, 33 deletions

diff --git a/src/widgets/dialogs/qfiledialog.cpp b/src/widgets/dialogs/qfiledialog.cpp
index 27696d2c51..1f832abf78 100644
--- a/src/widgets/dialogs/qfiledialog.cpp
+++ b/src/widgets/dialogs/qfiledialog.cpp
@@ -1187,13 +1187,13 @@ QList<QUrl> QFileDialogPrivate::userSelectedFiles() const
 
     const QModelIndexList selectedRows = qFileDialogUi->listView->selectionModel()->selectedRows();
     files.reserve(selectedRows.size());
-    foreach (const QModelIndex &index, selectedRows)
+    for (const QModelIndex &index : selectedRows)
         files.append(QUrl::fromLocalFile(index.data(QFileSystemModel::FilePathRole).toString()));
 
     if (files.isEmpty() && !lineEdit()->text().isEmpty()) {
         const QStringList typedFilesList = typedFiles();
         files.reserve(typedFilesList.size());
-        foreach (const QString &path, typedFilesList)
+        for (const QString &path : typedFilesList)
             files.append(QUrl::fromLocalFile(path));
     }
 
@@ -1257,7 +1257,7 @@ QStringList QFileDialog::selectedFiles() const
     QStringList files;
     const QList<QUrl> userSelectedFiles = d->userSelectedFiles();
     files.reserve(userSelectedFiles.size());
-    foreach (const QUrl &file, userSelectedFiles)
+    for (const QUrl &file : userSelectedFiles)
         files.append(file.toLocalFile());
     if (files.isEmpty() && d->usingWidgets()) {
         const FileMode fm = fileMode();
@@ -1284,7 +1284,7 @@ QList<QUrl> QFileDialog::selectedUrls() const
         QList<QUrl> urls;
         const QStringList selectedFileList = selectedFiles();
         urls.reserve(selectedFileList.size());
-        foreach (const QString &file, selectedFileList)
+        for (const QString &file : selectedFileList)
             urls.append(QUrl::fromLocalFile(file));
         return urls;
     }
@@ -1554,7 +1554,7 @@ void QFileDialog::setMimeTypeFilters(const QStringList &filters)
 {
     Q_D(QFileDialog);
     QStringList nameFilters;
-    foreach (const QString &mimeType, filters) {
+    for (const QString &mimeType : filters) {
         const QString text = nameFilterForMime(mimeType);
         if (!text.isEmpty())
             nameFilters.append(text);
@@ -2218,7 +2218,7 @@ QStringList QFileDialog::getOpenFileNames(QWidget *parent,
     const QList<QUrl> selectedUrls = getOpenFileUrls(parent, caption, QUrl::fromLocalFile(dir), filter, selectedFilter, options, schemes);
     QStringList fileNames;
     fileNames.reserve(selectedUrls.size());
-    foreach (const QUrl &url, selectedUrls)
+    for (const QUrl &url : selectedUrls)
         fileNames << url.toLocalFile();
     return fileNames;
 }
@@ -2696,7 +2696,7 @@ void QFileDialogPrivate::saveSettings()
     QStringList historyUrls;
     const QStringList history = q->history();
     historyUrls.reserve(history.size());
-    foreach (const QString &path, history)
+    for (const QString &path : history)
         historyUrls << QUrl::fromLocalFile(path).toString();
     settings.setValue(QLatin1String("history"), historyUrls);
     settings.setValue(QLatin1String("lastVisited"), lastVisitedDir()->toString());
@@ -2730,7 +2730,8 @@ bool QFileDialogPrivate::restoreFromSettings()
         return true;
 
     QStringList history;
-    foreach (const QString &urlStr, settings.value(QLatin1String("history")).toStringList()) {
+    const auto urlStrings = settings.value(QLatin1String("history")).toStringList();
+    for (const QString &urlStr : urlStrings) {
         QUrl url(urlStr);
         if (url.isLocalFile())
             history << url.toLocalFile();
@@ -2998,7 +2999,8 @@ void QFileDialogPrivate::createWidgets()
     q->setHistory(options->history());
     if (options->initiallySelectedFiles().count() == 1)
         q->selectFile(options->initiallySelectedFiles().first().fileName());
-    foreach (const QUrl &url, options->initiallySelectedFiles())
+    const auto initiallySelectedFiles = options->initiallySelectedFiles();
+    for (const QUrl &url : initiallySelectedFiles)
         q->selectUrl(url);
     lineEdit()->selectAll();
     _q_updateOkButton();
@@ -3755,7 +3757,7 @@ void QFileDialogPrivate::_q_emitUrlsSelected(const QList<QUrl> &files)
     Q_Q(QFileDialog);
     emit q->urlsSelected(files);
     QStringList localFiles;
-    foreach (const QUrl &file, files)
+    for (const QUrl &file : files)
         if (file.isLocalFile())
             localFiles.append(file.toLocalFile());
     if (!localFiles.isEmpty())
diff --git a/src/widgets/dialogs/qfontdialog.cpp b/src/widgets/dialogs/qfontdialog.cpp
index 688e8f5c13..659a311d34 100644
--- a/src/widgets/dialogs/qfontdialog.cpp
+++ b/src/widgets/dialogs/qfontdialog.cpp
@@ -481,7 +481,8 @@ void QFontDialogPrivate::updateFamilies()
     QFontDatabase fdb;
 
     QStringList familyNames;
-    foreach (const QString &family, fdb.families(writingSystem)) {
+    const auto families = fdb.families(writingSystem);
+    for (const QString &family : families) {
         if (fdb.isPrivateFamily(family))
             continue;
 
diff --git a/src/widgets/graphicsview/qgraphicsanchorlayout_p.cpp b/src/widgets/graphicsview/qgraphicsanchorlayout_p.cpp
index 5033264459..328d20be6e 100644
--- a/src/widgets/graphicsview/qgraphicsanchorlayout_p.cpp
+++ b/src/widgets/graphicsview/qgraphicsanchorlayout_p.cpp
@@ -602,10 +602,10 @@ QSimplexConstraint *GraphPath::constraint(const GraphPath &path) const
 QString GraphPath::toString() const
 {
     QString string(QLatin1String("Path: "));
-    foreach(AnchorData *edge, positives)
+    for (AnchorData *edge : positives)
         string += QString::fromLatin1(" (+++) %1").arg(edge->toString());
 
-    foreach(AnchorData *edge, negatives)
+    for (AnchorData *edge : negatives)
         string += QString::fromLatin1(" (---) %1").arg(edge->toString());
 
     return string;
@@ -1932,8 +1932,7 @@ void QGraphicsAnchorLayoutPrivate::removeVertex(QGraphicsLayoutItem *item, Qt::A
     if (AnchorVertex *v = internalVertex(item, edge)) {
         Graph<AnchorVertex, AnchorData> &g = graph[edgeOrientation(edge)];
         const QList<AnchorVertex *> allVertices = graph[edgeOrientation(edge)].adjacentVertices(v);
-        AnchorVertex *v2;
-        foreach (v2, allVertices) {
+        for (auto *v2 : allVertices) {
             g.removeEdge(v, v2);
             removeInternalVertex(item, edge);
             removeInternalVertex(v2->m_item, v2->m_edge);
@@ -2223,12 +2222,10 @@ bool QGraphicsAnchorLayoutPrivate::calculateTrunk(Orientation orientation, const
             // Calculate and set the preferred size for the layout,
             // from the edge sizes that were calculated above.
             qreal pref(0.0);
-            foreach (const AnchorData *ad, path.positives) {
+            for (const AnchorData *ad : path.positives)
                 pref += ad->sizeAtPreferred;
-            }
-            foreach (const AnchorData *ad, path.negatives) {
+            for (const AnchorData *ad : path.negatives)
                 pref -= ad->sizeAtPreferred;
-            }
 
             sizeHints[orientation][Qt::MinimumSize] = min;
             sizeHints[orientation][Qt::PreferredSize] = pref;
@@ -2368,8 +2365,8 @@ void QGraphicsAnchorLayoutPrivate::findPaths(Orientation orientation)
 */
 void QGraphicsAnchorLayoutPrivate::constraintsFromPaths(Orientation orientation)
 {
-    foreach (AnchorVertex *vertex, graphPaths[orientation].uniqueKeys())
-    {
+    const auto vertices = graphPaths[orientation].uniqueKeys();
+    for (AnchorVertex *vertex : vertices) {
         int valueCount = graphPaths[orientation].count(vertex);
         if (valueCount == 1)
             continue;
diff --git a/src/widgets/widgets/qabstractscrollarea.cpp b/src/widgets/widgets/qabstractscrollarea.cpp
index ed6b039c7c..946d683bf0 100644
--- a/src/widgets/widgets/qabstractscrollarea.cpp
+++ b/src/widgets/widgets/qabstractscrollarea.cpp
@@ -469,7 +469,7 @@ void QAbstractScrollAreaPrivate::layoutChildren()
     if ((vscrollOverlap > 0 && needv) || (hscrollOverlap > 0 && needh)) {
         const QList<QHeaderView *> headers = q->findChildren<QHeaderView*>();
         if (headers.count() <= 2) {
-            Q_FOREACH (const QHeaderView *header, headers) {
+            for (const QHeaderView *header : headers) {
                 const QRect geo = header->geometry();
                 if (header->orientation() == Qt::Vertical && header->isVisible() && QStyle::visualRect(opt.direction, opt.rect, geo).left() <= opt.rect.width() / 2)
                     vHeaderRight = QStyle::visualRect(opt.direction, opt.rect, geo).right();
diff --git a/src/widgets/widgets/qmdiarea.cpp b/src/widgets/widgets/qmdiarea.cpp
index a0a6e08688..50685667d3 100644
--- a/src/widgets/widgets/qmdiarea.cpp
+++ b/src/widgets/widgets/qmdiarea.cpp
@@ -408,7 +408,7 @@ void IconTiler::rearrange(QList<QWidget *> &widgets, const QRect &domain) const
 int MinOverlapPlacer::accumulatedOverlap(const QRect &source, const QVector<QRect> &rects)
 {
     int accOverlap = 0;
-    foreach (const QRect &rect, rects) {
+    for (const QRect &rect : rects) {
         QRect intersection = source.intersected(rect);
         accOverlap += intersection.width() * intersection.height();
     }
@@ -425,7 +425,7 @@ QRect MinOverlapPlacer::findMinOverlapRect(const QVector<QRect> &source, const Q
 {
     int minAccOverlap = -1;
     QRect minAccOverlapRect;
-    foreach (const QRect &srcRect, source) {
+    for (const QRect &srcRect : source) {
         const int accOverlap = accumulatedOverlap(srcRect, rects);
         if (accOverlap < minAccOverlap || minAccOverlap == -1) {
             minAccOverlap = accOverlap;
@@ -454,7 +454,7 @@ QVector<QRect> MinOverlapPlacer::getCandidatePlacements(const QSize &size, const
     if (domain.bottom() - size.height() + 1 >= 0)
         ylist << domain.bottom() - size.height() + 1;
 
-    foreach (const QRect &rect, rects) {
+    for (const QRect &rect : rects) {
         xlist << rect.right() + 1;
         ylist << rect.bottom() + 1;
     }
@@ -504,7 +504,7 @@ QVector<QRect> MinOverlapPlacer::findMaxOverlappers(const QRect &domain, const Q
     result.reserve(source.size());
 
     int maxOverlap = -1;
-    foreach (const QRect &srcRect, source) {
+    for (const QRect &srcRect : source) {
         QRect intersection = domain.intersected(srcRect);
         const int overlap = intersection.width() * intersection.height();
         if (overlap >= maxOverlap || maxOverlap == -1) {
@@ -549,7 +549,7 @@ QPoint MinOverlapPlacer::place(const QSize &size, const QVector<QRect> &rects,
 {
     if (size.isEmpty() || !domain.isValid())
         return QPoint();
-    foreach (const QRect &rect, rects) {
+    for (const QRect &rect : rects) {
         if (!rect.isValid())
             return QPoint();
     }
@@ -1237,7 +1237,8 @@ void QMdiAreaPrivate::internalRaise(QMdiSubWindow *mdiChild) const
 
     QMdiSubWindow *stackUnderChild = 0;
     if (!windowStaysOnTop(mdiChild)) {
-        foreach (QObject *object, viewport->children()) {
+        const auto children = viewport->children(); // take a copy, as raising/stacking under changes the order
+        for (QObject *object : children) {
             QMdiSubWindow *child = qobject_cast<QMdiSubWindow *>(object);
             if (!child || !childWindows.contains(child))
                 continue;
@@ -1392,7 +1393,7 @@ QMdiAreaPrivate::subWindowList(QMdiArea::WindowOrder order, bool reversed) const
                 list.prepend(child);
         }
     } else if (order == QMdiArea::StackingOrder) {
-        foreach (QObject *object, viewport->children()) {
+        for (QObject *object : viewport->children()) {
             QMdiSubWindow *child = qobject_cast<QMdiSubWindow *>(object);
             if (!child || !childWindows.contains(child))
                 continue;
@@ -1741,7 +1742,7 @@ QSize QMdiArea::sizeHint() const
 
     QSize desktopSize = QApplication::desktop()->size();
     QSize size(desktopSize.width() * 2 / scaleFactor, desktopSize.height() * 2 / scaleFactor);
-    foreach (QMdiSubWindow *child, d_func()->childWindows) {
+    for (QMdiSubWindow *child : d_func()->childWindows) {
         if (!sanityCheck(child, "QMdiArea::sizeHint"))
             continue;
         size = size.expandedTo(child->sizeHint());
@@ -1759,7 +1760,7 @@ QSize QMdiArea::minimumSizeHint() const
                style()->pixelMetric(QStyle::PM_TitleBarHeight, 0, this));
     size = size.expandedTo(QAbstractScrollArea::minimumSizeHint());
     if (!d->scrollBarsEnabled()) {
-        foreach (QMdiSubWindow *child, d->childWindows) {
+        for (QMdiSubWindow *child : d->childWindows) {
             if (!sanityCheck(child, "QMdiArea::sizeHint"))
                 continue;
             size = size.expandedTo(child->minimumSizeHint());
diff --git a/src/widgets/widgets/qmdisubwindow.cpp b/src/widgets/widgets/qmdisubwindow.cpp
index 0f38eee6cd..83a997dae0 100644
--- a/src/widgets/widgets/qmdisubwindow.cpp
+++ b/src/widgets/widgets/qmdisubwindow.cpp
@@ -2206,8 +2206,8 @@ void QMdiSubWindowPrivate::setSizeGrip(QSizeGrip *newSizeGrip)
 void QMdiSubWindowPrivate::setSizeGripVisible(bool visible) const
 {
     // See if we can find any size grips
-    QList<QSizeGrip *> sizeGrips = q_func()->findChildren<QSizeGrip *>();
-    foreach (QSizeGrip *grip, sizeGrips)
+    const QList<QSizeGrip *> sizeGrips = q_func()->findChildren<QSizeGrip *>();
+    for (QSizeGrip *grip : sizeGrips)
         grip->setVisible(visible);
 }