define display_context interface, implement in game_board

src/display_context.hpp

@@ -0,0 +1,40 @@
+/*
+   Copyright (C) 2014 by Chris Beck <render787@gmail.com>
+   Part of the Battle for Wesnoth Project http://www.wesnoth.org/
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2 of the License, or
+   (at your option) any later version.
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY.
+
+   See the COPYING file for more details.
+*/
+
+/**
+ *
+ * This class is an abstract base class designed to simplify the use
+ * of the display object.
+ *
+ **/
+
+#ifndef DISPLAY_CONTEXT_HPP_INCLUDED
+#define DISPLAY_CONTEXT_HPP_INCLUDED
+
+#include<vector>
+
+class team;
+class gamemap;
+class unit_map;
+
+class display_context {
+public:
+	virtual const std::vector<team> & teams() const = 0;
+	virtual const gamemap & map() const = 0;
+	virtual const unit_map & units() const = 0;
+
+	virtual ~display_context() {}
+};
+
+#endif

src/game_board.hpp

@@ -17,6 +17,7 @@
 
 #include "global.hpp"
 
+#include "display_context.hpp"
 #include "map.hpp"
 #include "team.hpp"
 #include "unit_map.hpp"
@@ -46,7 +47,7 @@ namespace events {
  *
  **/
 
-class game_board {
+class game_board : public display_context {
 
 	std::vector<team> teams_;
 
@@ -82,13 +83,14 @@ class game_board {
 
 	public:
 
-	// Constructors and const accessors
+	// Constructors, trivial dtor, and const accessors
 
 	game_board(const config & game_config, const config & level) : teams_(), map_(game_config, level), units_() {}
+	virtual ~game_board() {}
 
-	const std::vector<team> & teams() const { return teams_; }
-	const gamemap & map() const { return map_; }
-	const unit_map & units() const { return units_; }
+	virtual const std::vector<team> & teams() const { return teams_; }
+	virtual const gamemap & map() const { return map_; }
+	virtual const unit_map & units() const { return units_; }
 
 	// Saving