From 656b3b9c2862114eb84ea0eea5225568015515f5 Mon Sep 17 00:00:00 2001
From: Robin Gareus <robin@gareus.org>
Date: Mon, 12 Sep 2016 12:02:07 +0200
Subject: [PATCH] Add a Lua wrapper to Glib::build_filename()

---
 libs/ardour/ardour/lua_api.h |  8 ++++++++
 libs/ardour/lua_api.cc       | 20 ++++++++++++++++++++
 libs/ardour/luabindings.cc   |  1 +
 3 files changed, 29 insertions(+)

diff --git a/libs/ardour/ardour/lua_api.h b/libs/ardour/ardour/lua_api.h
index 9af9649620..f737eddc4b 100644
--- a/libs/ardour/ardour/lua_api.h
+++ b/libs/ardour/ardour/lua_api.h
@@ -130,6 +130,14 @@ namespace ARDOUR { namespace LuaAPI {
 	 * @returns 4 parameters: red, green, blue, alpha (in range 0..1)
 	 */
 	int hsla_to_rgba (lua_State *lua);
+
+	/* Creates a filename from a series of elements using the correct separator for filenames.
+	 *
+	 * No attempt is made to force the resulting filename to be an absolute path.
+	 * If the first element is a relative path, the result will be a relative path.
+	 */
+	int build_filename (lua_State *lua);
+
 } } /* namespace */
 
 namespace ARDOUR { namespace LuaOSC {
diff --git a/libs/ardour/lua_api.cc b/libs/ardour/lua_api.cc
index 890e268c59..1cf403b8b0 100644
--- a/libs/ardour/lua_api.cc
+++ b/libs/ardour/lua_api.cc
@@ -346,6 +346,26 @@ ARDOUR::LuaAPI::hsla_to_rgba (lua_State *L)
 	return 4;
 }
 
+int
+ARDOUR::LuaAPI::build_filename (lua_State *L)
+{
+	std::vector<std::string> elem;
+	int top = lua_gettop(L);
+	if (top < 1) {
+    return luaL_argerror (L, 1, "invalid number of arguments, build_filename (path, ...)");
+	}
+	for (int i = 1; i <= top; ++i) {
+		int lt = lua_type (L, i);
+		if (lt != LUA_TSTRING) {
+			return luaL_argerror (L, i, "invalid argument type, expected string");
+		}
+		elem.push_back (luaL_checkstring(L, i));
+	}
+
+	luabridge::Stack<std::string>::push (L, Glib::build_filename (elem));
+	return 1;
+}
+
 luabridge::LuaRef::Proxy&
 luabridge::LuaRef::Proxy::clone_instance (const void* classkey, void* p) {
   lua_rawgeti (m_L, LUA_REGISTRYINDEX, m_tableRef);
diff --git a/libs/ardour/luabindings.cc b/libs/ardour/luabindings.cc
index 3dce7f592a..e8b65353a5 100644
--- a/libs/ardour/luabindings.cc
+++ b/libs/ardour/luabindings.cc
@@ -1468,6 +1468,7 @@ LuaBindings::common (lua_State* L)
 		.addCFunction ("plugin_automation", ARDOUR::LuaAPI::plugin_automation)
 		.addCFunction ("hsla_to_rgba", ARDOUR::LuaAPI::hsla_to_rgba)
 		.addFunction ("usleep", Glib::usleep)
+		.addCFunction ("build_filename", ARDOUR::LuaAPI::build_filename)
 		.endNamespace () // end LuaAPI
 		.endNamespace ();// end ARDOUR
 }