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, 17 insertions, 25 deletions

diff --git a/src/widgets/kernel/qapplication.cpp b/src/widgets/kernel/qapplication.cpp
index 4510fc85b6..ab8c251f50 100644
--- a/src/widgets/kernel/qapplication.cpp
+++ b/src/widgets/kernel/qapplication.cpp
@@ -1125,9 +1125,9 @@ QStyle *QApplication::style()
         QStyle *&app_style = QApplicationPrivate::app_style;
         app_style = QStyleFactory::create(style);
         if (!app_style) {
-            QStringList styles = QStyleFactory::keys();
-            for (int i = 0; i < styles.size(); ++i) {
-                if ((app_style = QStyleFactory::create(styles.at(i))))
+            const QStringList styles = QStyleFactory::keys();
+            for (const auto &style : styles) {
+                if ((app_style = QStyleFactory::create(style)))
                     break;
             }
         }
@@ -1742,8 +1742,7 @@ void QApplicationPrivate::notifyWindowIconChanged()
     QWindowList windowList = QGuiApplication::topLevelWindows();
 
     // send to all top-level QWidgets
-    for (int i = 0; i < list.size(); ++i) {
-        QWidget *w = list.at(i);
+    for (auto *w : list) {
         windowList.removeOne(w->windowHandle());
         QCoreApplication::sendEvent(w, &ev);
     }
@@ -1906,9 +1905,8 @@ bool QApplicationPrivate::tryCloseAllWidgetWindows(QWindowList *processedWindows
     }
 
 retry:
-    QWidgetList list = QApplication::topLevelWidgets();
-    for (int i = 0; i < list.size(); ++i) {
-        QWidget *w = list.at(i);
+    const QWidgetList list = QApplication::topLevelWidgets();
+    for (auto *w : list) {
         if (w->isVisible() && w->windowType() != Qt::Desktop &&
                 !w->testAttribute(Qt::WA_DontShowOnScreen) && !w->data->is_closing) {
             QWindow *window = w->windowHandle();
@@ -1995,9 +1993,8 @@ bool QApplication::event(QEvent *e)
         ce->accept();
         closeAllWindows();
 
-        QWidgetList list = topLevelWidgets();
-        for (int i = 0; i < list.size(); ++i) {
-            QWidget *w = list.at(i);
+        const QWidgetList list = topLevelWidgets();
+        for (auto *w : list) {
             if (w->isVisible() && !(w->windowType() == Qt::Desktop) && !(w->windowType() == Qt::Popup) &&
                  (!(w->windowType() == Qt::Dialog) || !w->parentWidget())) {
                 ce->ignore();
@@ -2011,9 +2008,8 @@ bool QApplication::event(QEvent *e)
     } else if (e->type() == QEvent::LocaleChange) {
         // on Windows the event propagation is taken care by the
         // WM_SETTINGCHANGE event handler.
-        QWidgetList list = topLevelWidgets();
-        for (int i = 0; i < list.size(); ++i) {
-            QWidget *w = list.at(i);
+        const QWidgetList list = topLevelWidgets();
+        for (auto *w : list) {
             if (!(w->windowType() == Qt::Desktop)) {
                 if (!w->testAttribute(Qt::WA_SetLocale))
                     w->d_func()->setLocale_helper(QLocale(), true);
@@ -2057,9 +2053,8 @@ bool QApplication::event(QEvent *e)
     }
 
     if(e->type() == QEvent::LanguageChange) {
-        QWidgetList list = topLevelWidgets();
-        for (int i = 0; i < list.size(); ++i) {
-            QWidget *w = list.at(i);
+        const QWidgetList list = topLevelWidgets();
+        for (auto *w : list) {
             if (!(w->windowType() == Qt::Desktop))
                 postEvent(w, new QEvent(QEvent::LanguageChange));
         }
@@ -2085,8 +2080,7 @@ void QApplicationPrivate::notifyLayoutDirectionChange()
     QWindowList windowList = QGuiApplication::topLevelWindows();
 
     // send to all top-level QWidgets
-    for (int i = 0; i < list.size(); ++i) {
-        QWidget *w = list.at(i);
+    for (auto *w : list) {
         windowList.removeAll(w->windowHandle());
         QEvent ev(QEvent::ApplicationLayoutDirectionChange);
         QCoreApplication::sendEvent(w, &ev);
@@ -2137,9 +2131,8 @@ void QApplication::setActiveWindow(QWidget* act)
 
     if (QApplicationPrivate::active_window) {
         if (style()->styleHint(QStyle::SH_Widget_ShareActivation, 0, QApplicationPrivate::active_window)) {
-            QWidgetList list = topLevelWidgets();
-            for (int i = 0; i < list.size(); ++i) {
-                QWidget *w = list.at(i);
+            const QWidgetList list = topLevelWidgets();
+            for (auto *w : list) {
                 if (w->isVisible() && w->isActiveWindow())
                     toBeDeactivated.append(w);
             }
@@ -2160,9 +2153,8 @@ void QApplication::setActiveWindow(QWidget* act)
 
     if (QApplicationPrivate::active_window) {
         if (style()->styleHint(QStyle::SH_Widget_ShareActivation, 0, QApplicationPrivate::active_window)) {
-            QWidgetList list = topLevelWidgets();
-            for (int i = 0; i < list.size(); ++i) {
-                QWidget *w = list.at(i);
+            const QWidgetList list = topLevelWidgets();
+            for (auto *w : list) {
                 if (w->isVisible() && w->isActiveWindow())
                     toBeActivated.append(w);
             }