Save Lua UI scripts separately

Previously EditorAction and ExitorHook scripts were saved with
instant.xml. The were saved with each session and in the config
dir (for new sessions). This allowed inconsistent UI setups, especially
when loading old sessions that had no or different scripts.

Now Editor scripts (actions and hooks) are saved in a dedicated file,
session-independently. This goes along with ui_config in general
e.g. action-table-columns

The scripts are not saved with ui_config file for two reasons:
ui_config settings related to built-in  ui_config_vars.h,
and in the future there may be further indirection like "ui-rc-file".

Note: previously loaded editor scripts are lost with this change.

gtk2_ardour/editor.cc

@@ -2578,7 +2578,7 @@ Editor::set_state (const XMLNode& node, int version)
 		}
 	}
 
-	return LuaInstance::instance()->set_state(node);
+	return 0;
 }
 
 XMLNode&
@@ -2646,8 +2646,6 @@ Editor::get_state ()
 
 	node->set_property ("nudge-clock-value", nudge_clock->current_duration());
 
-	node->add_child_nocopy (LuaInstance::instance()->get_action_state());
-	node->add_child_nocopy (LuaInstance::instance()->get_hook_state());
 	node->add_child_nocopy (_locations->get_state ());
 
 	return *node;

gtk2_ardour/luainstance.cc

@@ -20,6 +20,7 @@
 #include <cairomm/surface.h>
 #include <pango/pangocairo.h>
 
+#include "pbd/file_utils.h"
 #include "pbd/strsplit.h"
 
 #include "gtkmm2ext/bindings.h"
@@ -28,6 +29,7 @@
 #include "ardour/audioengine.h"
 #include "ardour/disk_reader.h"
 #include "ardour/disk_writer.h"
+#include "ardour/filesystem_paths.h"
 #include "ardour/plugin_manager.h"
 #include "ardour/route.h"
 #include "ardour/session.h"
@@ -54,6 +56,8 @@
 
 #include "pbd/i18n.h"
 
+static const char* ui_scripts_file_name = "ui_scripts";
+
 namespace LuaCairo {
 /** wrap RefPtr< Cairo::ImageSurface >
  *
@@ -1092,7 +1096,7 @@ LuaInstance::LuaInstance ()
 	lua.Print.connect (&_lua_print);
 	init ();
 
-	LuaScriptParamList args;
+	load_state ();
 }
 
 LuaInstance::~LuaInstance ()
@@ -1266,6 +1270,61 @@ LuaInstance::init ()
 	lua_setglobal (L, "Editor");
 }
 
+int
+LuaInstance::load_state ()
+{
+	std::string uiscripts;
+	if (!find_file (ardour_config_search_path(), ui_scripts_file_name, uiscripts)) {
+		return -1;
+	}
+	XMLTree tree;
+
+	info << string_compose (_("Loading user ui scripts file %1"), uiscripts) << endmsg;
+
+	if (!tree.read (uiscripts)) {
+		error << string_compose(_("cannot read ui scripts file \"%1\""), uiscripts) << endmsg;
+		return -1;
+	}
+
+	if (set_state (*tree.root())) {
+		error << string_compose(_("user ui scripts file \"%1\" not loaded successfully."), uiscripts) << endmsg;
+		return -1;
+	}
+
+	return 0;
+}
+
+int
+LuaInstance::save_state ()
+{
+	if (!_session) {
+		/* action scripts are un-registered with the session */
+		return -1;
+	}
+
+	std::string uiscripts = Glib::build_filename (user_config_directory(), ui_scripts_file_name);
+
+	XMLNode* node = new XMLNode (X_("UIScripts"));
+	node->add_child_nocopy (get_action_state ());
+	node->add_child_nocopy (get_hook_state ());
+
+	XMLTree tree;
+	tree.set_root (node);
+
+	if (!tree.write (uiscripts.c_str())){
+		error << string_compose (_("UI script file %1 not saved"), uiscripts) << endmsg;
+		return -1;
+	}
+	return 0;
+}
+
+void
+LuaInstance::set_dirty ()
+{
+	save_state ();
+	_session->set_dirty (); // XXX is this reasonable?
+}
+
 void LuaInstance::set_session (Session* s)
 {
 	SessionHandlePtr::set_session (s);
@@ -1273,6 +1332,8 @@ void LuaInstance::set_session (Session* s)
 		return;
 	}
 
+	load_state ();
+
 	lua_State* L = lua.getState();
 	LuaBindings::set_session (L, _session);
 
@@ -1537,7 +1598,7 @@ LuaInstance::set_lua_action (
 	} catch (...) {
 		return false;
 	}
-	_session->set_dirty ();
+	set_dirty ();
 	return true;
 }
 
@@ -1553,7 +1614,7 @@ LuaInstance::remove_lua_action (const int id)
 		return false;
 	}
 	ActionChanged (id, ""); /* EMIT SIGNAL */
-	_session->set_dirty ();
+	set_dirty ();
 	return true;
 }
 
@@ -1678,7 +1739,7 @@ LuaInstance::register_lua_slot (const std::string& name, const std::string& scri
 	} catch (luabridge::LuaException const& e) {
 		cerr << "LuaException:" << e.what () << endl;
 	} catch (...) { }
-	_session->set_dirty ();
+	set_dirty ();
 	return false;
 }
 
@@ -1691,7 +1752,7 @@ LuaInstance::unregister_lua_slot (const PBD::ID& id)
 		_callbacks.erase (i);
 		return true;
 	}
-	_session->set_dirty ();
+	set_dirty ();
 	return false;
 }
 

gtk2_ardour/luainstance.h

@@ -100,6 +100,9 @@ public:
 	XMLNode& get_action_state (void);
 	XMLNode& get_hook_state (void);
 
+	int load_state ();
+	int save_state ();
+
 	bool interactive_add (ARDOUR::LuaScriptInfo::ScriptType, int);
 
 	/* actions */
@@ -131,6 +134,7 @@ private:
 	static LuaInstance* _instance;
 
 	void init ();
+	void set_dirty ();
 	void session_going_away ();
 
 	LuaState lua;