config: Rework unsubscribing

Unsubscribe by object comparison, making separate tracking of
subscriptions and a dedicated method for clearing them obsolete.

src/config.py

@@ -155,11 +155,11 @@ class Config:
             self.subscriptions[variable] = [func]
         func(self.variables[variable])
 
-    def unsubscribe(self, variable, func):
-        if variable in self.subscriptions and func in self.subscriptions[variable]:
-            self.subscriptions[variable].remove(func)
-        else:
-            print(f'Unsubscribing non-subscribed function {func}!')
+    def unsubscribe(self, obj):
+        for subs in self.subscriptions.values():
+            for func in subs:
+                if func.__self__ == obj:
+                    subs.remove(func)
 
 
 config = Config()

src/ui/page.py

@@ -8,13 +8,6 @@ class Page:
     image: Union[str, Path, None] = None
     can_reload: bool = False
 
-    def _subscribe(self, variable, func):
-        config.subscribe(variable, func)
-        if hasattr(self, "subscriptions"):
-            self.subscriptions.append((variable, func))
-        else:
-            self.subscriptions = [(variable, func)]
-
     ### dummy stubs ###
 
     def load(self):
@@ -31,10 +24,3 @@ class Page:
         Called before the page is no longer shown. Used for e.g. storing current enrty values.
         '''
         pass
-
-    ### public methods ###
-
-    def cancel_subscriptions(self):
-        if hasattr(self, "subscriptions"):
-            for variable, func in self.subscriptions:
-                config.unsubscribe(variable, func)

src/ui/pages/keyboard.py

@@ -47,7 +47,7 @@ class KeyboardLayoutPage(Gtk.Box, Page):
         self.layout_list.bind_model(
             self.model, lambda o: ProgressRow(o.name, o))
 
-        self._subscribe('keyboard_language', self._update_keyboard_language)
+        config.subscribe('keyboard_language', self._update_keyboard_language)
 
     ### callbacks ###
 
@@ -82,7 +82,7 @@ class KeyboardOverviewPage(Gtk.Box, Page):
             keyboard = get_default_layout(language_code)
             set_system_keyboard_layout(keyboard_info=keyboard)
 
-        self._subscribe('keyboard_layout', self._update_primary_layout)
+        config.subscribe('keyboard_layout', self._update_primary_layout)
 
     ### callbacks ###
 

src/ui/pages/locale.py

@@ -28,8 +28,8 @@ class LocalePage(Gtk.Box, Page):
             timezone = get_current_timezone()
             config.set('timezone', timezone)
 
-        self._subscribe('formats_ui', self._update_formats)
-        self._subscribe('timezone', self._update_timezone)
+        config.subscribe('formats_ui', self._update_formats)
+        config.subscribe('timezone', self._update_timezone)
 
     ### callbacks ###
 

src/ui/widgets.py

@@ -4,6 +4,8 @@ from pathlib import Path
 
 from gi.repository import Adw, Gtk
 
+from .config import config
+
 
 def reset_model(model, new_values):
     '''
@@ -109,7 +111,7 @@ class PageWrapper(Adw.Bin):
         self.content.set_child(self.page)
 
     def __del__(self):
-        self.page.cancel_subscriptions()
+        config.unsubscribe(self.page)
 
     def get_page(self):
         return self.page