Eradicate Q_FOREACH loops [1/2]: trivial cases

In this patch, we port Q_FOREACH loops to C++11 ranged-for loops. All cases are
trivial in the sense that either the argument is already const or is trivially
marked as const, either by qAsConst(), or, in the case of rvalues, by storing
to a const auto temporary first.

In addition, all loop bodies are clear enough to confirm that the container we
iterate over is not changed under iteration. This does not exclude cases where
a loop is prematurely exited just after calling a modifier on the container, as
that is safe, if not especially elegant.

Change-Id: I87a63f07797437d421567d60e52305391a3c4f21
Reviewed-by: Johan Helsing <johan.helsing@qt.io>

src/plugins/platforms/wayland/plugins/shellintegration/wl-shell/qwaylandwlshellintegration.cpp

@@ -49,7 +49,8 @@ namespace QtWaylandClient {
 
 bool QWaylandWlShellIntegration::initialize(QWaylandDisplay *display)
 {
-    Q_FOREACH (QWaylandDisplay::RegistryGlobal global, display->globals()) {
+    const auto globals = display->globals();
+    for (QWaylandDisplay::RegistryGlobal global : globals) {
         if (global.interface == QLatin1String("wl_shell")) {
             m_wlShell = new QtWayland::wl_shell(display->wl_registry(), global.id, 1);
             break;

src/plugins/platforms/wayland/plugins/shellintegration/xdg-shell-v5/qwaylandxdgshellv5integration.cpp

@@ -51,7 +51,8 @@ namespace QtWaylandClient {
 
 bool QWaylandXdgShellV5Integration::initialize(QWaylandDisplay *display)
 {
-    Q_FOREACH (QWaylandDisplay::RegistryGlobal global, display->globals()) {
+    const auto globals = display->globals();
+    for (QWaylandDisplay::RegistryGlobal global : globals) {
         if (global.interface == QLatin1String("xdg_shell")) {
             m_xdgShell.reset(new QWaylandXdgShellV5(display->wl_registry(), global.id));
             break;

src/plugins/platforms/wayland/qwaylanddatasource.cpp

@@ -60,7 +60,8 @@ QWaylandDataSource::QWaylandDataSource(QWaylandDataDeviceManager *dataDeviceMana
 {
     if (!mimeData)
         return;
-    Q_FOREACH (const QString &format, mimeData->formats()) {
+    const auto formats = mimeData->formats();
+    for (const QString &format : formats) {
         offer(format);
     }
 }

src/plugins/platforms/wayland/qwaylanddisplay.cpp

@@ -366,7 +366,7 @@ void QWaylandDisplay::registry_global_remove(uint32_t id)
                     }
                 }
 
-                foreach (QWaylandScreen *screen, mScreens) {
+                for (QWaylandScreen *screen : qAsConst(mScreens)) {
                     if (screen->outputId() == id) {
                         mScreens.removeOne(screen);
                         QWindowSystemInterface::handleScreenRemoved(screen);

src/plugins/platforms/wayland/qwaylandinputcontext.cpp

@@ -221,11 +221,11 @@ void QWaylandTextInput::zwp_text_input_v2_leave(uint32_t serial, ::wl_surface *s
 
 void QWaylandTextInput::zwp_text_input_v2_modifiers_map(wl_array *map)
 {
-    QList<QByteArray> modifiersMap = QByteArray::fromRawData(static_cast<const char*>(map->data), map->size).split('\0');
+    const QList<QByteArray> modifiersMap = QByteArray::fromRawData(static_cast<const char*>(map->data), map->size).split('\0');
 
     m_modifiersMap.clear();
 
-    Q_FOREACH (const QByteArray &modifier, modifiersMap) {
+    for (const QByteArray &modifier : modifiersMap) {
         if (modifier == "Shift")
             m_modifiersMap.append(Qt::ShiftModifier);
         else if (modifier == "Control")

src/plugins/platforms/wayland/qwaylandinputdevice.cpp

@@ -1349,7 +1349,7 @@ bool QWaylandInputDevice::Touch::allTouchPointsReleased()
 
 void QWaylandInputDevice::Touch::releasePoints()
 {
-    Q_FOREACH (const QWindowSystemInterface::TouchPoint &previousPoint, mPrevTouchPoints) {
+    for (const QWindowSystemInterface::TouchPoint &previousPoint : qAsConst(mPrevTouchPoints)) {
         QWindowSystemInterface::TouchPoint tp = previousPoint;
         tp.state = Qt::TouchPointReleased;
         mTouchPoints.append(tp);

src/plugins/platforms/wayland/qwaylandintegration.cpp

@@ -421,7 +421,7 @@ void QWaylandIntegration::initializeShellIntegration()
         preferredShells << QLatin1String("wl-shell") << QLatin1String("ivi-shell");
     }
 
-    Q_FOREACH (QString preferredShell, preferredShells) {
+    for (const QString &preferredShell : qAsConst(preferredShells)) {
         mShellIntegration.reset(createShellIntegration(preferredShell));
         if (mShellIntegration) {
             qCDebug(lcQpaWayland, "Using the '%s' shell integration", qPrintable(preferredShell));

src/plugins/platforms/wayland/qwaylandscreen.cpp

@@ -175,7 +175,8 @@ QList<QPlatformScreen *> QWaylandScreen::virtualSiblings() const
 
 void QWaylandScreen::setOrientationUpdateMask(Qt::ScreenOrientations mask)
 {
-    foreach (QWindow *window, QGuiApplication::allWindows()) {
+    const auto allWindows = QGuiApplication::allWindows();
+    for (QWindow *window : allWindows) {
         QWaylandWindow *w = static_cast<QWaylandWindow *>(window->handle());
         if (w && w->waylandScreen() == this)
             w->setOrientationMask(mask);

src/plugins/platforms/wayland/qwaylandshmbackingstore.cpp

@@ -243,7 +243,8 @@ void QWaylandShmBackingStore::resize(const QSize &size, const QRegion &)
 
 QWaylandShmBuffer *QWaylandShmBackingStore::getBuffer(const QSize &size)
 {
-    foreach (QWaylandShmBuffer *b, mBuffers) {
+    const auto copy = mBuffers; // remove when ported to vector<unique_ptr> + remove_if
+    for (QWaylandShmBuffer *b : copy) {
         if (!b->busy()) {
             if (b->size() == size) {
                 return b;

src/plugins/platforms/wayland/qwaylandwindow.cpp

@@ -94,7 +94,8 @@ QWaylandWindow::~QWaylandWindow()
         reset(false);
 
     const QWindow *parent = window();
-    foreach (QWindow *w, QGuiApplication::topLevelWindows()) {
+    const auto tlw = QGuiApplication::topLevelWindows();
+    for (QWindow *w : tlw) {
         if (w->transientParent() == parent)
             QWindowSystemInterface::handleCloseEvent(w);
     }
@@ -786,7 +787,7 @@ bool QWaylandWindow::createDecoration()
     }
 
     if (hadDecoration != (bool)mWindowDecoration) {
-        foreach (QWaylandSubSurface *subsurf, mChildren) {
+        for (QWaylandSubSurface *subsurf : qAsConst(mChildren)) {
             QPoint pos = subsurf->window()->geometry().topLeft();
             QMargins m = frameMargins();
             subsurf->set_position(pos.x() + m.left(), pos.y() + m.top());

src/plugins/platforms/wayland/shared/qwaylandinputmethodeventbuilder.cpp

@@ -157,7 +157,7 @@ QInputMethodEvent QWaylandInputMethodEventBuilder::buildPreedit(const QString &t
         attributes.append(QInputMethodEvent::Attribute(QInputMethodEvent::Cursor, indexFromWayland(text, m_preeditCursor), 1, QVariant()));
     }
 
-    Q_FOREACH (const QInputMethodEvent::Attribute &attr, m_preeditStyles) {
+    for (const QInputMethodEvent::Attribute &attr : qAsConst(m_preeditStyles)) {
         int start = indexFromWayland(text, attr.start);
         int length = indexFromWayland(text, attr.start + attr.length) - start;
         attributes.append(QInputMethodEvent::Attribute(attr.type, start, length, attr.value));

src/tools/qtwaylandscanner/qtwaylandscanner.cpp

@@ -542,7 +542,7 @@ bool Scanner::process()
 
             if (hasEvents) {
                 printf("\n");
-                foreach (const WaylandEvent &e, interface.events) {
+                for (const WaylandEvent &e : interface.events) {
                     printf("        void send_");
                     printEvent(e);
                     printf(";\n");
@@ -563,7 +563,7 @@ bool Scanner::process()
 
             if (hasRequests) {
                 printf("\n");
-                foreach (const WaylandEvent &e, interface.requests) {
+                for (const WaylandEvent &e : interface.requests) {
                     printf("        virtual void %s_", interfaceNameStripped);
                     printEvent(e);
                     printf(";\n");
@@ -826,7 +826,7 @@ bool Scanner::process()
                 printf("\n");
                 printf("    };\n");
 
-                foreach (const WaylandEvent &e, interface.requests) {
+                for (const WaylandEvent &e : interface.requests) {
                     printf("\n");
                     printf("    void %s::%s_", interfaceName, interfaceNameStripped);
                     printEvent(e, true);
@@ -996,7 +996,7 @@ bool Scanner::process()
 
             if (!interface.requests.isEmpty()) {
                 printf("\n");
-                foreach (const WaylandEvent &e, interface.requests) {
+                for (const WaylandEvent &e : interface.requests) {
                     const WaylandArgument *new_id = newIdArgument(e.arguments);
                     QByteArray new_id_str = "void ";
                     if (new_id) {
@@ -1016,7 +1016,7 @@ bool Scanner::process()
             if (hasEvents) {
                 printf("\n");
                 printf("    protected:\n");
-                foreach (const WaylandEvent &e, interface.events) {
+                for (const WaylandEvent &e : interface.events) {
                     printf("        virtual void %s_", interfaceNameStripped);
                     printEvent(e);
                     printf(";\n");

tests/auto/wayland/shared_old/mockcompositor.cpp

@@ -221,8 +221,8 @@ QSharedPointer<MockSurface> MockCompositor::surface()
     QSharedPointer<MockSurface> result;
     lock();
     {
-        QVector<Impl::Surface *> surfaces = m_compositor->surfaces();
+        const QVector<Impl::Surface *> surfaces = m_compositor->surfaces();
-        foreach (Impl::Surface *surface, surfaces) {
+        for (Impl::Surface *surface : surfaces) {
             // we don't want to mistake the cursor surface for a window surface
             if (surface->isMapped()) {
                 result = surface->mockSurface();