From 021fa9fa5ce103ae5843647fee3d5d1d7038d32f Mon Sep 17 00:00:00 2001
From: "Steinar H. Gunderson" <sgunderson@bigfoot.com>
Date: Tue, 11 Jun 2019 22:31:30 +0200
Subject: [PATCH] Move some Lua utility functions into a separate header file.

---
 nageru/lua_utils.h | 77 ++++++++++++++++++++++++++++++++++++++++++++++
 nageru/theme.cpp   | 54 +-------------------------------
 2 files changed, 78 insertions(+), 53 deletions(-)
 create mode 100644 nageru/lua_utils.h

diff --git a/nageru/lua_utils.h b/nageru/lua_utils.h
new file mode 100644
index 0000000..102d7c5
--- /dev/null
+++ b/nageru/lua_utils.h
@@ -0,0 +1,77 @@
+#ifndef _LUA_UTILS_H
+#define _LUA_UTILS_H 1
+
+#include <lauxlib.h>
+#include <lua.hpp>
+
+#include <mutex>
+#include <utility>
+
+class LuaRefWithDeleter {
+public:
+	LuaRefWithDeleter(std::mutex *m, lua_State *L, int ref) : m(m), L(L), ref(ref) {}
+	~LuaRefWithDeleter() {
+		std::lock_guard<std::mutex> lock(*m);
+		luaL_unref(L, LUA_REGISTRYINDEX, ref);
+	}
+	int get() const { return ref; }
+
+private:
+	LuaRefWithDeleter(const LuaRefWithDeleter &) = delete;
+
+	std::mutex *m;
+	lua_State *L;
+	int ref;
+};
+
+template<class T, class... Args>
+int wrap_lua_object(lua_State* L, const char *class_name, Args&&... args)
+{
+	// Construct the C++ object and put it on the stack.
+	void *mem = lua_newuserdata(L, sizeof(T));
+	new(mem) T(std::forward<Args>(args)...);
+
+	// Look up the metatable named <class_name>, and set it on the new object.
+	luaL_getmetatable(L, class_name);
+	lua_setmetatable(L, -2);
+
+	return 1;
+}
+
+// Like wrap_lua_object, but the object is not owned by Lua; ie. it's not freed
+// by Lua GC. This is typically the case for Effects, which are owned by EffectChain
+// and expected to be destructed by it. The object will be of type T** instead of T*
+// when exposed to Lua.
+//
+// Note that we currently leak if you allocate an Effect in this way and never call
+// add_effect. We should see if there's a way to e.g. set __gc on it at construction time
+// and then release that once add_effect() takes ownership.
+template<class T, class... Args>
+int wrap_lua_object_nonowned(lua_State* L, const char *class_name, Args&&... args)
+{
+	// Construct the pointer ot the C++ object and put it on the stack.
+	T **obj = (T **)lua_newuserdata(L, sizeof(T *));
+	*obj = new T(std::forward<Args>(args)...);
+
+	// Look up the metatable named <class_name>, and set it on the new object.
+	luaL_getmetatable(L, class_name);
+	lua_setmetatable(L, -2);
+
+	return 1;
+}
+
+template<class T>
+int wrap_lua_existing_object_nonowned(lua_State* L, const char *class_name, T *ptr)
+{
+	// Construct the pointer ot the C++ object and put it on the stack.
+	T **obj = (T **)lua_newuserdata(L, sizeof(T *));
+	*obj = ptr;
+
+	// Look up the metatable named <class_name>, and set it on the new object.
+	luaL_getmetatable(L, class_name);
+	lua_setmetatable(L, -2);
+
+	return 1;
+}
+
+#endif  // !defined(_LUA_UTILS_H)
diff --git a/nageru/theme.cpp b/nageru/theme.cpp
index 780c7ce..71a59a2 100644
--- a/nageru/theme.cpp
+++ b/nageru/theme.cpp
@@ -37,6 +37,7 @@
 #include "flags.h"
 #include "image_input.h"
 #include "input_state.h"
+#include "lua_utils.h"
 #include "pbo_frame_allocator.h"
 
 class Mixer;
@@ -115,59 +116,6 @@ InputStateInfo::InputStateInfo(const InputState &input_state)
 	}
 }
 
-class LuaRefWithDeleter {
-public:
-	LuaRefWithDeleter(mutex *m, lua_State *L, int ref) : m(m), L(L), ref(ref) {}
-	~LuaRefWithDeleter() {
-		lock_guard<mutex> lock(*m);
-		luaL_unref(L, LUA_REGISTRYINDEX, ref);
-	}
-	int get() const { return ref; }
-
-private:
-	LuaRefWithDeleter(const LuaRefWithDeleter &) = delete;
-
-	mutex *m;
-	lua_State *L;
-	int ref;
-};
-
-template<class T, class... Args>
-int wrap_lua_object(lua_State* L, const char *class_name, Args&&... args)
-{
-	// Construct the C++ object and put it on the stack.
-	void *mem = lua_newuserdata(L, sizeof(T));
-	new(mem) T(forward<Args>(args)...);
-
-	// Look up the metatable named <class_name>, and set it on the new object.
-	luaL_getmetatable(L, class_name);
-	lua_setmetatable(L, -2);
-
-	return 1;
-}
-
-// Like wrap_lua_object, but the object is not owned by Lua; ie. it's not freed
-// by Lua GC. This is typically the case for Effects, which are owned by EffectChain
-// and expected to be destructed by it. The object will be of type T** instead of T*
-// when exposed to Lua.
-//
-// Note that we currently leak if you allocate an Effect in this way and never call
-// add_effect. We should see if there's a way to e.g. set __gc on it at construction time
-// and then release that once add_effect() takes ownership.
-template<class T, class... Args>
-int wrap_lua_object_nonowned(lua_State* L, const char *class_name, Args&&... args)
-{
-	// Construct the pointer ot the C++ object and put it on the stack.
-	T **obj = (T **)lua_newuserdata(L, sizeof(T *));
-	*obj = new T(forward<Args>(args)...);
-
-	// Look up the metatable named <class_name>, and set it on the new object.
-	luaL_getmetatable(L, class_name);
-	lua_setmetatable(L, -2);
-
-	return 1;
-}
-
 enum EffectType {
 	WHITE_BALANCE_EFFECT,
 	RESAMPLE_EFFECT,
-- 
2.39.2