Add a couple of signals to make handling the loading of session confi…

…g easier

lisp/application.py

@@ -49,6 +49,7 @@
 class Application(metaclass=Singleton):
     def __init__(self, app_conf):
         self.session_created = Signal()
+        self.session_initialised = Signal()
         self.session_before_finalize = Signal()
 
         self.__conf = app_conf
@@ -142,6 +143,7 @@ def __new_session_dialog(self):
                     self.__load_from_file(dialog.sessionPath)
                 else:
                     self.__new_session(dialog.selected())
+                    self.session_initialised.emit(self.__session)
             else:
                 if self.__session is None:
                     # If the user close the dialog, and no layout exists
@@ -215,6 +217,8 @@ def __load_from_file(self, session_file):
             for plugin_name, plugin_config in session_dict['session']['plugins'].items():
                 self.__session.set_plugin_session_config(plugin_name, plugin_config)
 
+            self.session_initialised.emit(self.__session)
+
             # Load cues
             for cues_dict in session_dict.get("cues", {}):
                 cue_type = cues_dict.pop("_type_", "Undefined")

lisp/core/plugin.py

@@ -37,7 +37,8 @@ def __init__(self, app):
         """:type app: lisp.application.Application"""
         self.__app = app
 
-        app.session_created.connect(self._on_session_init)
+        app.session_created.connect(self._on_session_created)
+        app.session_initialised.connect(self._on_session_initialised)
 
     @property
     def app(self):
@@ -47,6 +48,28 @@ def app(self):
     def finalize(self):
         """Called when the application is getting closed."""
 
-    def _on_session_init(self):
-        """Called each time a session is initialised (eg. when a session is created or opened)."""
+    def _on_session_created(self):
+        """Called immediately after a session is created.
+
+        In the case of a file load, this gets called before the session
+        properties and cues are restored.
+        """
         self.SessionConfig = PluginSessionConfig(self)
+        self.SessionConfig.changed.connect(self._on_session_config_altered)
+        self.SessionConfig.updated.connect(self._on_session_config_altered)
+
+    def _on_session_initialised(self, _):
+        """Called once a session is fully initialised.
+
+        For new sessions, there is not much difference between this and `app.session_created`
+
+        For loaded sessions, this is called *after* the various showfile properties have
+        been set, but *before* the cues are restored.
+        """
+        pass
+
+    def _on_session_config_altered(self, _):
+        """Called whenever the session config is changed or updated in any way."""
+        pass
+
+