From 5a66c688616485a834925ec1f4289a75ca44d646 Mon Sep 17 00:00:00 2001
From: Jared Boone <jboone@earfeast.com>
Date: Sun, 7 Feb 2016 11:24:25 -0800
Subject: [PATCH] Return Widget::children() by reference.

---
 firmware/common/ui_widget.cpp | 8 +++++---
 firmware/common/ui_widget.hpp | 6 ++++--
 2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/firmware/common/ui_widget.cpp b/firmware/common/ui_widget.cpp
index 8125c30e..788b7abf 100644
--- a/firmware/common/ui_widget.cpp
+++ b/firmware/common/ui_widget.cpp
@@ -46,6 +46,8 @@ bool is_dirty() {
 
 /* Widget ****************************************************************/
 
+const std::vector<Widget*> Widget::no_children { };
+
 Point Widget::screen_pos() {
 	return screen_rect().pos;
 }
@@ -153,8 +155,8 @@ bool Widget::on_touch(const TouchEvent event) {
 	return false;
 }
 
-const std::vector<Widget*> Widget::children() const {
-	return { };
+const std::vector<Widget*>& Widget::children() const {
+	return no_children;
 }
 
 Context& Widget::context() const {
@@ -244,7 +246,7 @@ void View::remove_child(Widget* const widget) {
 	}
 }
 
-const std::vector<Widget*> View::children() const {
+const std::vector<Widget*>& View::children() const {
 	return children_;
 }
 
diff --git a/firmware/common/ui_widget.hpp b/firmware/common/ui_widget.hpp
index bf53ffd5..4a3e080c 100644
--- a/firmware/common/ui_widget.hpp
+++ b/firmware/common/ui_widget.hpp
@@ -94,7 +94,7 @@ public:
 	virtual bool on_key(const KeyEvent event);
 	virtual bool on_encoder(const EncoderEvent event);
 	virtual bool on_touch(const TouchEvent event);
-	virtual const std::vector<Widget*> children() const;
+	virtual const std::vector<Widget*>& children() const;
 
 	virtual Context& context() const;
 
@@ -136,6 +136,8 @@ private:
 		.highlighted = false,
 		.visible = false,
 	};
+
+	static const std::vector<Widget*> no_children;
 };
 
 class View : public Widget {
@@ -154,7 +156,7 @@ public:
 	void add_child(Widget* const widget);
 	void add_children(const std::vector<Widget*>& children);
 	void remove_child(Widget* const widget);
-	const std::vector<Widget*> children() const override;
+	const std::vector<Widget*>& children() const override;
 
 	virtual std::string title() const;