QtWidgets: eradicate Q_FOREACH loops [rvalues]

... by replacing them with C++11 range-for loops.

This is the simplest of the patch series: Q_FOREACH took a
copy, so we do, too. Except we don't, since we're just
catching the return value that comes out of the function
(RVO). We can't feed the rvalues into range-for, because
they are non-const and would thus detach.

Saves 2.2KiB in test size on optimized GCC 5.3 Linux AMD64
builds.

Change-Id: I914aa20fe65577b2e32ea7ea89d51a8d003a57ba
Reviewed-by: Olivier Goffart (Woboq GmbH) <ogoffart@woboq.com>

src/widgets/itemviews/qtableview.cpp

@@ -2016,8 +2016,8 @@ QRegion QTableView::visualRegionForSelection(const QItemSelection &selection) co
             if (viewportRect.intersects(rangeRect))
                 selectionRegion += rangeRect;
             if (d->hasSpans()) {
-                foreach (QSpanCollection::Span *s,
+                const auto spansInRect = d->spans.spansInRect(range.left(), range.top(), range.width(), range.height());
-                         d->spans.spansInRect(range.left(), range.top(), range.width(), range.height())) {
+                for (QSpanCollection::Span *s : spansInRect) {
                     if (range.contains(s->top(), s->left(), range.parent())) {
                         const QRect &visualSpanRect = d->visualSpanRect(*s);
                         if (viewportRect.intersects(visualSpanRect))

src/widgets/kernel/qapplication.cpp

@@ -1718,9 +1718,11 @@ QString QApplicationPrivate::desktopStyleKey()
     // first valid one.
     if (const QPlatformTheme *theme = QGuiApplicationPrivate::platformTheme()) {
         const QStringList availableKeys = QStyleFactory::keys();
-        foreach (const QString &style, theme->themeHint(QPlatformTheme::StyleNames).toStringList())
+        const auto styles = theme->themeHint(QPlatformTheme::StyleNames).toStringList();
+        for (const QString &style : styles) {
             if (availableKeys.contains(style, Qt::CaseInsensitive))
                 return style;
+        }
     }
     return QString();
 }
@@ -2225,10 +2227,13 @@ QWidget *qt_tlw_for_window(QWindow *wnd)
         else
             break;
     }
-    if (wnd)
+    if (wnd) {
-        foreach (QWidget *tlw, qApp->topLevelWidgets())
+        const auto tlws = qApp->topLevelWidgets();
+        for (QWidget *tlw : tlws) {
             if (tlw->windowHandle() == wnd)
                 return tlw;
+        }
+    }
     return 0;
 }
 
@@ -3942,7 +3947,8 @@ void QApplication::alert(QWidget *widget, int duration)
         if (QWindow *window= QApplicationPrivate::windowForWidget(widget))
             window->alert(duration);
     } else {
-        foreach (QWidget *topLevel, topLevelWidgets())
+        const auto topLevels = topLevelWidgets();
+        for (QWidget *topLevel : topLevels)
             QApplication::alert(topLevel, duration);
     }
 }

src/widgets/kernel/qgesturemanager.cpp

@@ -219,7 +219,8 @@ QGesture *QGestureManager::getState(QObject *object, QGestureRecognizer *recogni
     }
 
     // check if the QGesture for this recognizer has already been created
-    foreach (QGesture *state, m_objectGestures.value(QGestureManager::ObjectGesture(object, type))) {
+    const auto states = m_objectGestures.value(QGestureManager::ObjectGesture(object, type));
+    for (QGesture *state : states) {
         if (m_gestureToRecognizer.value(state) == recognizer)
             return state;
     }
@@ -684,7 +685,8 @@ void QGestureManager::deliverEvents(const QSet<QGesture *> &gestures,
 
         QApplication::sendEvent(receiver, &event);
         bool eventAccepted = event.isAccepted();
-        foreach(QGesture *gesture, event.gestures()) {
+        const auto eventGestures = event.gestures();
+        for (QGesture *gesture : eventGestures) {
             if (eventAccepted || event.isAccepted(gesture)) {
                 QWidget *w = event.m_targetWidgets.value(gesture->gestureType(), 0);
                 Q_ASSERT(w);
@@ -710,7 +712,8 @@ void QGestureManager::deliverEvents(const QSet<QGesture *> &gestures,
             QGestureEvent event(it.value());
             QApplication::sendEvent(it.key(), &event);
             bool eventAccepted = event.isAccepted();
-            foreach (QGesture *gesture, event.gestures()) {
+            const auto eventGestures = event.gestures();
+            for (QGesture *gesture : eventGestures) {
                 if (gesture->state() == Qt::GestureStarted &&
                     (eventAccepted || event.isAccepted(gesture))) {
                     QWidget *w = event.m_targetWidgets.value(gesture->gestureType(), 0);

src/widgets/kernel/qwhatsthis.cpp

@@ -375,11 +375,9 @@ class QWhatsThisPrivate : public QObject
 
 void QWhatsThisPrivate::notifyToplevels(QEvent *e)
 {
-    QWidgetList toplevels = QApplication::topLevelWidgets();
+    const QWidgetList toplevels = QApplication::topLevelWidgets();
-    for (int i = 0; i < toplevels.count(); ++i) {
+    for (auto *w : toplevels)
-        QWidget *w = toplevels.at(i);
         QApplication::sendEvent(w, e);
-    }
 }
 
 QWhatsThisPrivate *QWhatsThisPrivate::instance = 0;

src/widgets/kernel/qwidget.cpp

@@ -1417,7 +1417,8 @@ void QWidgetPrivate::create_sys(WId window, bool initializeWindow, bool destroyO
         win = topData()->window;
     }
 
-    foreach (const QByteArray &propertyName, q->dynamicPropertyNames()) {
+    const auto dynamicPropertyNames = q->dynamicPropertyNames();
+    for (const QByteArray &propertyName : dynamicPropertyNames) {
         if (!qstrncmp(propertyName, "_q_platform_", 12))
             win->setProperty(propertyName, q->property(propertyName));
     }
@@ -11984,7 +11985,9 @@ QWidget *QWidgetPrivate::widgetInNavigationDirection(Direction direction)
 
     QWidget *targetWidget = 0;
     int shortestDistance = INT_MAX;
-    foreach(QWidget *targetCandidate, QApplication::allWidgets()) {
+
+    const auto targetCandidates = QApplication::allWidgets();
+    for (QWidget *targetCandidate : targetCandidates) {
 
         const QRect targetCandidateRect = targetCandidate->rect().translated(targetCandidate->mapToGlobal(QPoint()));
 

src/widgets/styles/qwindowsxpstyle.cpp

@@ -406,10 +406,12 @@ HWND QWindowsXPStylePrivate::winId(const QWidget *widget)
             return hwnd;
 
     // Find top level with native window (there might be dialogs that do not have one).
-    foreach (const QWidget *toplevel, QApplication::topLevelWidgets())
+    const auto topLevels = QApplication::topLevelWidgets();
+    for (const QWidget *toplevel : topLevels) {
         if (toplevel->windowHandle() && toplevel->windowHandle()->handle())
             if (const HWND topLevelHwnd = QApplicationPrivate::getHWNDForWidget(toplevel))
                 return topLevelHwnd;
+    }
 
     if (QDesktopWidget *desktop = qApp->desktop())
         if (const HWND desktopHwnd = QApplicationPrivate::getHWNDForWidget(desktop))

src/widgets/util/qflickgesture.cpp

@@ -581,7 +581,8 @@ QGestureRecognizer::Result QFlickGestureRecognizer::recognize(QGesture *state,
 
     // Check for an active scroller at globalPos
     if (inputType == QScroller::InputPress) {
-        foreach (QScroller *as, QScroller::activeScrollers()) {
+        const auto activeScrollers = QScroller::activeScrollers();
+        for (QScroller *as : activeScrollers) {
             if (as != scroller) {
                 QRegion scrollerRegion;
 
@@ -589,11 +590,13 @@ QGestureRecognizer::Result QFlickGestureRecognizer::recognize(QGesture *state,
                     scrollerRegion = QRect(w->mapToGlobal(QPoint(0, 0)), w->size());
 #ifndef QT_NO_GRAPHICSVIEW
                 } else if (QGraphicsObject *go = qobject_cast<QGraphicsObject *>(as->target())) {
-                    if (go->scene()) {
+                    if (const auto *scene = go->scene()) {
                         const auto goBoundingRectMappedToScene = go->mapToScene(go->boundingRect());
-                        foreach (QGraphicsView *gv, go->scene()->views())
+                        const auto views = scene->views();
+                        for (QGraphicsView *gv : views) {
                             scrollerRegion |= gv->mapFromScene(goBoundingRectMappedToScene)
                                               .translated(gv->mapToGlobal(QPoint(0, 0)));
+                        }
                     }
 #endif
                 }

src/widgets/widgets/qdialogbuttonbox.cpp

@@ -964,7 +964,8 @@ bool QDialogButtonBox::event(QEvent *event)
                 break;
         }
 
-        foreach (QPushButton *pb, (dialog ? dialog : this)->findChildren<QPushButton *>()) {
+        const auto pbs = (dialog ? dialog : this)->findChildren<QPushButton *>();
+        for (QPushButton *pb : pbs) {
             if (pb->isDefault() && pb != firstAcceptButton) {
                 hasDefault = true;
                 break;

src/widgets/widgets/qmenu.cpp

@@ -1270,14 +1270,17 @@ void QMenuPrivate::_q_platformMenuAboutToShow()
     Q_Q(QMenu);
 
 #ifdef Q_OS_OSX
-    if (platformMenu)
+    if (platformMenu) {
-        Q_FOREACH (QAction *action, q->actions())
+        const auto actions = q->actions();
+        for (QAction *action : actions) {
             if (QWidget *widget = widgetItems.value(action))
                 if (widget->parent() == q) {
                     QPlatformMenuItem *menuItem = platformMenu->menuItemForTag(reinterpret_cast<quintptr>(action));
                     moveWidgetToPlatformItem(widget, menuItem);
                     platformMenu->syncMenuItem(menuItem);
                 }
+        }
+    }
 #endif
 
     emit q->aboutToShow();