From 3873c51781e453b86e9b97495172713f24adfabb Mon Sep 17 00:00:00 2001
From: Andreas Kling <awesomekling@gmail.com>
Date: Mon, 27 May 2019 04:18:24 +0200
Subject: [PATCH] LibCore: Add CObject::for_each_child_of_type<T>()

Use this to iterate over all the GRadioButtons in a group.
---
 LibCore/CObject.h       | 15 +++++++++++++--
 LibGUI/GRadioButton.cpp |  4 +---
 LibGUI/GRadioButton.h   |  7 +++++++
 3 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/LibCore/CObject.h b/LibCore/CObject.h
index 92fe544edd9..a4eac52eec2 100644
--- a/LibCore/CObject.h
+++ b/LibCore/CObject.h
@@ -29,6 +29,8 @@ public:
         }
     }
 
+    template<typename T, typename Callback> void for_each_child_of_type(Callback callback);
+
     CObject* parent() { return m_parent; }
     const CObject* parent() const { return m_parent; }
 
@@ -59,8 +61,7 @@ private:
     Vector<CObject*> m_children;
 };
 
-template<typename T> inline bool is(const CObject&) { return false; }
-template<> inline bool is<CObject>(const CObject&) { return true; }
+template<typename T> inline bool is(const CObject&) { return true; }
 
 template<typename T>
 inline T& to(CObject& object)
@@ -75,3 +76,13 @@ inline const T& to(const CObject& object)
     ASSERT(is<T>(object));
     return static_cast<const T&>(object);
 }
+
+template<typename T, typename Callback>
+inline void CObject::for_each_child_of_type(Callback callback)
+{
+    for_each_child([&] (auto& child) {
+        if (is<T>(child))
+            return callback(to<T>(child));
+        return IterationDecision::Continue;
+    });
+}
diff --git a/LibGUI/GRadioButton.cpp b/LibGUI/GRadioButton.cpp
index 773bfd2369f..afcb2d9c32c 100644
--- a/LibGUI/GRadioButton.cpp
+++ b/LibGUI/GRadioButton.cpp
@@ -55,9 +55,7 @@ void GRadioButton::for_each_in_group(Callback callback)
 {
     if (!parent())
         return;
-    for_each_child_widget([&] (auto& child) {
-        if (!child.is_radio_button())
-            return IterationDecision::Continue;
+    parent()->for_each_child_of_type<GRadioButton>([&] (auto& child) {
         return callback(static_cast<GRadioButton&>(child));
     });
 }
diff --git a/LibGUI/GRadioButton.h b/LibGUI/GRadioButton.h
index 21496b8c954..95897f5b47e 100644
--- a/LibGUI/GRadioButton.h
+++ b/LibGUI/GRadioButton.h
@@ -20,3 +20,10 @@ private:
     template<typename Callback> void for_each_in_group(Callback);
     static Size circle_size();
 };
+
+template<> inline bool is<GRadioButton>(const CObject& object)
+{
+    if (!is<GWidget>(object))
+        return false;
+    return to<GWidget>(object).is_radio_button();
+}