feat: add subscription method for Page trait

cosmic-settings/src/app.rs

@@ -42,8 +42,6 @@ use cosmic::{
 #[cfg(feature = "wayland")]
 use cosmic_panel_config::CosmicPanelConfig;
 use cosmic_settings_page::{self as page, section};
-#[cfg(feature = "page-accessibility")]
-use cosmic_settings_subscriptions::accessibility::subscription as a11y_subscription;
 #[cfg(feature = "wayland")]
 use desktop::{
     dock,
@@ -290,7 +288,9 @@ impl cosmic::Application for SettingsApp {
     }
 
     fn subscription(&self) -> Subscription<Message> {
-        Subscription::batch(vec![
+        let page = &self.pages.page[self.active_page];
+
+        let subscriptions = vec![
             #[cfg(feature = "ashpd")]
             crate::subscription::daytime().map(|daytime| {
                 Message::PageMessage(pages::Message::Appearance(appearance::Message::Daytime(
@@ -313,6 +313,7 @@ impl cosmic::Application for SettingsApp {
             // Watch for changes to installed desktop entries
             desktop_files(0).map(|_| Message::DesktopInfo),
             // Watch for configuration changes to the panel.
+            // TODO: This should only be active when the panel page is active.
             #[cfg(feature = "wayland")]
             self.core()
                 .watch_config::<CosmicPanelConfig>("com.system76.CosmicPanel.Panel")
@@ -323,6 +324,7 @@ impl cosmic::Application for SettingsApp {
 
                     Message::PanelConfig(update.config)
                 }),
+            // TODO: This should only be active when the dock page is active.
             #[cfg(feature = "wayland")]
             self.core()
                 .watch_config::<CosmicPanelConfig>("com.system76.CosmicPanel.Dock")
@@ -333,21 +335,10 @@ impl cosmic::Application for SettingsApp {
 
                     Message::PanelConfig(update.config)
                 }),
-            // Watch for state changes from the cosmic-bg session service.
+            page.subscription(self.core()).map(Message::PageMessage),
-            self.core()
+        ];
-                .watch_state::<cosmic_bg_config::state::State>(cosmic_bg_config::NAME)
+
-                .map(|update| {
+        Subscription::batch(subscriptions)
-                    Message::PageMessage(pages::Message::DesktopWallpaper(
-                        pages::desktop::wallpaper::Message::UpdateState(update.config),
-                    ))
-                }),
-            #[cfg(feature = "page-accessibility")]
-            a11y_subscription().map(|m| {
-                Message::PageMessage(pages::Message::Accessibility(
-                    pages::accessibility::Message::DBusUpdate(m),
-                ))
-            }),
-        ])
     }
 
     #[allow(clippy::too_many_lines)]

cosmic-settings/src/pages/accessibility/mod.rs

@@ -13,7 +13,9 @@ use cosmic_settings_page::{
     self as page, Insert,
     section::{self, Section},
 };
-use cosmic_settings_subscriptions::accessibility::{DBusRequest, DBusUpdate};
+use cosmic_settings_subscriptions::accessibility::{
+    DBusRequest, DBusUpdate, subscription as a11y_subscription,
+};
 use cosmic_settings_subscriptions::cosmic_a11y_manager;
 use num_traits::FromPrimitive;
 use slotmap::SlotMap;
@@ -88,6 +90,18 @@ pub enum Message {
     ScreenReaderEnabled(bool),
 }
 
+impl From<Message> for crate::pages::Message {
+    fn from(message: Message) -> Self {
+        crate::pages::Message::Accessibility(message)
+    }
+}
+
+impl From<Message> for crate::app::Message {
+    fn from(message: Message) -> Self {
+        crate::app::Message::PageMessage(message.into())
+    }
+}
+
 impl page::Page<crate::pages::Message> for Page {
     fn set_id(&mut self, entity: page::Entity) {
         self.entity = entity;
@@ -150,6 +164,13 @@ impl page::Page<crate::pages::Message> for Page {
 
         cosmic::Task::none()
     }
+
+    fn subscription(
+        &self,
+        _core: &cosmic::Core,
+    ) -> cosmic::iced::Subscription<crate::pages::Message> {
+        a11y_subscription().map(|m| super::Message::Accessibility(Message::DBusUpdate(m)))
+    }
 }
 
 impl page::AutoBind<crate::pages::Message> for Page {

cosmic-settings/src/pages/desktop/wallpaper/mod.rs

@@ -293,6 +293,17 @@ impl page::Page<crate::pages::Message> for Page {
             .title(fl!("color-picker"))
         })
     }
+
+    /// Watch for state changes from the cosmic-bg session service.
+    fn subscription(
+        &self,
+        core: &cosmic::Core,
+    ) -> cosmic::iced::Subscription<crate::pages::Message> {
+        core.watch_state::<cosmic_bg_config::state::State>(cosmic_bg_config::NAME)
+            .map(|update| {
+                crate::pages::Message::DesktopWallpaper(Message::UpdateState(update.config))
+            })
+    }
 }
 
 impl page::AutoBind<crate::pages::Message> for Page {}

page/src/lib.rs

@@ -5,7 +5,7 @@ mod binder;
 pub use binder::{AutoBind, Binder};
 
 mod insert;
-use cosmic::{Element, Task, app::ContextDrawer};
+use cosmic::{Element, Task, app::ContextDrawer, iced::Subscription};
 use downcast_rs::{Downcast, impl_downcast};
 pub use insert::Insert;
 
@@ -89,6 +89,12 @@ pub trait Page<Message: Clone + 'static>: Downcast {
         Task::none()
     }
 
+    /// Subscription unique to the page when it is active.
+    #[inline]
+    fn subscription(&self, _core: &cosmic::Core) -> Subscription<Message> {
+        Subscription::none()
+    }
+
     /// Assigns the entity ID of the page to the page.
     #[allow(unused)]
     #[inline]