LibGUI: Add GWidget::for_each_child_widget(callback).

LibGUI/GRadioButton.cpp

@@ -55,13 +55,11 @@ void GRadioButton::for_each_in_group(Callback callback)
 {
     if (!parent())
         return;
-    for (auto& object : parent()->children()) {
-        if (!object->is_widget())
-            continue;
-        if (!static_cast<GWidget*>(object)->is_radio_button())
-            continue;
-        callback(*static_cast<GRadioButton*>(object));
-    }
+    for_each_child_widget([&] (auto& child) {
+        if (!child.is_radio_button())
+            return IterationDecision::Continue;
+        return callback(static_cast<GRadioButton&>(child));
+    });
 }
 
 void GRadioButton::click()
@@ -71,6 +69,7 @@ void GRadioButton::click()
     for_each_in_group([this] (auto& button) {
         if (&button != this)
             button.set_checked(false);
+        return IterationDecision::Continue;
     });
     set_checked(true);
 }

LibGUI/GSplitter.cpp

@@ -40,17 +40,15 @@ void GSplitter::mousedown_event(GMouseEvent& event)
     GWidget* first_resizee { nullptr };
     GWidget* second_resizee { nullptr };
     int fudge = layout()->spacing();
-    for (auto* child : children()) {
-        if (!child->is_widget())
-            continue;
-        auto& child_widget = *static_cast<GWidget*>(child);
-        int child_start = m_orientation == Orientation::Horizontal ? child_widget.relative_rect().left() : child_widget.relative_rect().top();
-        int child_end = m_orientation == Orientation::Horizontal ? child_widget.relative_rect().right() : child_widget.relative_rect().bottom();
+    for_each_child_widget([&] (auto& child) {
+        int child_start = m_orientation == Orientation::Horizontal ? child.relative_rect().left() : child.relative_rect().top();
+        int child_end = m_orientation == Orientation::Horizontal ? child.relative_rect().right() : child.relative_rect().bottom();
         if (x_or_y > child_end && (x_or_y - fudge) <= child_end)
-            first_resizee = &child_widget;
+            first_resizee = &child;
         if (x_or_y < child_start && (x_or_y + fudge) >= child_start)
-            second_resizee = &child_widget;
-    }
+            second_resizee = &child;
+        return IterationDecision::Continue;
+    });
     ASSERT(first_resizee && second_resizee);
     m_first_resizee = first_resizee->make_weak_ptr();
     m_second_resizee = second_resizee->make_weak_ptr();

LibGUI/GTabWidget.cpp

@@ -61,12 +61,10 @@ void GTabWidget::child_event(CChildEvent& event)
     } else if (event.type() == GEvent::ChildRemoved) {
         if (m_active_widget == &child) {
             GWidget* new_active_widget = nullptr;
-            for (auto* new_child : children()) {
-                if (new_child->is_widget()) {
-                    new_active_widget = static_cast<GWidget*>(new_child);
-                    break;
-                }
-            }
+            for_each_child_widget([&] (auto& new_child) {
+                new_active_widget = &new_child;
+                return IterationDecision::Abort;
+            });
             set_active_widget(new_active_widget);
         }
     }

LibGUI/GWidget.cpp

@@ -116,15 +116,15 @@ void GWidget::handle_paint_event(GPaintEvent& event)
 #endif
     }
     paint_event(event);
-    for (auto* ch : children()) {
-        auto* child = (GWidget*)ch;
-        if (!child->is_visible())
-            continue;
-        if (child->relative_rect().intersects(event.rect())) {
-            GPaintEvent local_event(event.rect().intersected(child->relative_rect()).translated(-child->relative_position()));
-            child->event(local_event);
+    for_each_child_widget([&] (auto& child) {
+        if (!child.is_visible())
+            return IterationDecision::Continue;
+        if (child.relative_rect().intersects(event.rect())) {
+            GPaintEvent local_event(event.rect().intersected(child.relative_rect()).translated(-child.relative_position()));
+            child.event(local_event);
         }
-    }
+        return IterationDecision::Continue;
+    });
     second_paint_event(event);
 }
 

LibGUI/GWidget.h

@@ -185,6 +185,16 @@ public:
     void register_local_shortcut_action(Badge<GAction>, GAction&);
     void unregister_local_shortcut_action(Badge<GAction>, GAction&);
 
+    template<typename Callback>
+    void for_each_child_widget(Callback callback)
+    {
+        for_each_child([&] (auto& child) {
+            if (child.is_widget())
+                return callback(static_cast<GWidget&>(child));
+            return IterationDecision::Continue;
+        });
+    }
+
     virtual bool is_radio_button() const { return false; }
 
 private:

LibGUI/GWindow.cpp

@@ -526,16 +526,14 @@ Vector<GWidget*> GWindow::focusable_widgets() const
     Function<void(GWidget&)> collect_focusable_widgets = [&] (GWidget& widget) {
         if (widget.accepts_focus())
             collected_widgets.append(&widget);
-        for (auto& child : widget.children()) {
-            if (!child->is_widget())
-                continue;
-            auto& child_widget = *static_cast<GWidget*>(child);
-            if (!child_widget.is_visible())
-                continue;
-            if (!child_widget.is_enabled())
-                continue;
-            collect_focusable_widgets(child_widget);
-        }
+        widget.for_each_child_widget([&] (auto& child) {
+            if (!child.is_visible())
+                return IterationDecision::Continue;
+            if (!child.is_enabled())
+                return IterationDecision::Continue;
+            collect_focusable_widgets(child);
+            return IterationDecision::Continue;
+        });
     };
 
     collect_focusable_widgets(*m_main_widget);