improv: create subscription channel for pages to send messages to

Cargo.lock

@@ -1349,6 +1349,7 @@ dependencies = [
  "once_cell",
  "regex",
  "slotmap",
+ "tokio",
  "url",
 ]
 

Cargo.toml

@@ -5,6 +5,8 @@ resolver = "2"
 rust-version = "1.71.0"
 sunrise_sunset = "1.0.1"
 
+[workspace.dependencies]
+tokio = { version = "1.37.0", features = ["macros"] }
 
 [workspace.dependencies.libcosmic]
 git = "https://github.com/pop-os/libcosmic"

cosmic-settings/Cargo.toml

@@ -6,7 +6,7 @@ license = "GPL-3.0"
 rust-version = "1.65.0"
 
 [dependencies]
-tokio = { version = "1.35.1", features = ["macros"] }
+tokio.workspace = true
 async-channel = "2.1.1"
 color-eyre = "0.6.2"
 cosmic-bg-config = { workspace = true }

cosmic-settings/src/app.rs

@@ -6,16 +6,17 @@ use crate::pages::desktop::{
     self, appearance, dock,
     panel::{
         self,
-        applets_inner::{self, AppletsPage, APPLET_DND_ICON_ID},
+        applets_inner::{self, APPLET_DND_ICON_ID},
         inner as _panel,
     },
 };
-use crate::pages::input::{self, keyboard};
+use crate::pages::input::{self};
-use crate::pages::{self, display, networking, sound, system, time};
+use crate::pages::{self, display, sound, system, time};
 use crate::subscription::desktop_files;
 use crate::widget::{page_title, search_header};
 use crate::PageCommands;
 use cosmic::app::DbusActivationMessage;
+use cosmic::iced::futures::SinkExt;
 use cosmic::iced::Subscription;
 use cosmic::widget::{button, row, text_input};
 use cosmic::{
@@ -42,6 +43,7 @@ pub struct SettingsApp {
     config: Config,
     core: Core,
     nav_model: nav_bar::Model,
+    page_sender: Option<tokio::sync::mpsc::Sender<crate::pages::Message>>,
     pages: page::Binder<crate::pages::Message>,
     search_active: bool,
     search_id: cosmic::widget::Id,
@@ -77,19 +79,21 @@ impl SettingsApp {
 
 #[derive(Clone, Debug)]
 pub enum Message {
+    CloseContextDrawer,
+    DelayedInit(page::Entity),
     DesktopInfo,
     Error(String),
+    OpenContextDrawer(Cow<'static, str>),
     Page(page::Entity),
     PageMessage(crate::pages::Message),
     PanelConfig(CosmicPanelConfig),
+    RegisterSubscriptionSender(tokio::sync::mpsc::Sender<pages::Message>),
     SearchActivate,
     SearchChanged(String),
     SearchClear,
     SearchSubmit,
-    SetWindowTitle,
-    OpenContextDrawer(Cow<'static, str>),
-    CloseContextDrawer,
     SetTheme(cosmic::theme::Theme),
+    SetWindowTitle,
 }
 
 impl cosmic::Application for SettingsApp {
@@ -113,6 +117,7 @@ impl cosmic::Application for SettingsApp {
             config: Config::new(),
             core,
             nav_model: nav_bar::Model::default(),
+            page_sender: None,
             pages: page::Binder::default(),
             search_active: false,
             search_id: cosmic::widget::Id::unique(),
@@ -136,9 +141,10 @@ impl cosmic::Application for SettingsApp {
         }
         .unwrap_or(desktop_id);
 
-        let command = app.activate_page(active_id);
+        (
-
+            app,
-        (app, command)
+            cosmic::command::message(cosmic::app::message::app(Message::DelayedInit(active_id))),
+        )
     }
 
     fn nav_model(&self) -> Option<&nav_bar::Model> {
@@ -208,6 +214,23 @@ impl cosmic::Application for SettingsApp {
         });
 
         Subscription::batch(vec![
+            // Creates a channel that listens to messages from pages.
+            // The sender is given back to the application so that it may pass it on.
+            cosmic::iced::subscription::channel(
+                std::any::TypeId::of::<Self>(),
+                4,
+                move |mut output| async move {
+                    let (tx, mut rx) = tokio::sync::mpsc::channel::<pages::Message>(4);
+
+                    let _res = output.send(Message::RegisterSubscriptionSender(tx)).await;
+
+                    while let Some(event) = rx.recv().await {
+                        let _res = output.send(Message::PageMessage(event)).await;
+                    }
+
+                    futures::future::pending().await
+                },
+            ),
             crate::subscription::daytime().map(|daytime| {
                 Message::PageMessage(pages::Message::Appearance(appearance::Message::Daytime(
                     daytime,
@@ -409,6 +432,21 @@ impl cosmic::Application for SettingsApp {
             Message::Error(error) => {
                 tracing::error!(error, "error occurred");
             }
+
+            Message::RegisterSubscriptionSender(sender) => {
+                self.page_sender = Some(sender);
+            }
+
+            // It is necessary to delay init to allow time for the page sender to be initialized
+            Message::DelayedInit(active_id) => {
+                if self.page_sender.is_none() {
+                    return cosmic::command::message(cosmic::app::message::app(
+                        Message::DelayedInit(active_id),
+                    ));
+                }
+
+                return self.activate_page(active_id);
+            }
         }
 
         Command::none()
@@ -438,7 +476,7 @@ impl cosmic::Application for SettingsApp {
         } else if let Some(sub_pages) = self.pages.sub_pages(self.active_page) {
             self.sub_page_view(sub_pages)
         } else {
-            panic!("page without sub-pages or content");
+            return row::row().into();
         };
 
         let padding = if self.core.is_condensed() {
@@ -518,9 +556,14 @@ impl SettingsApp {
         self.search_active = false;
         self.activate_navbar(page);
 
+        let sender = self
+            .page_sender
+            .clone()
+            .expect("sender should be available");
+
         let page_command = self
             .pages
-            .page_reload(page)
+            .on_enter(page, sender)
             .map(Message::PageMessage)
             .map(cosmic::app::Message::App);
 

cosmic-settings/src/pages/desktop/appearance.rs

@@ -1087,7 +1087,11 @@ impl page::Page<crate::pages::Message> for Page {
             .description(fl!("appearance", "desc"))
     }
 
-    fn reload(&mut self, _: page::Entity) -> Command<crate::pages::Message> {
+    fn on_enter(
+        &mut self,
+        _: page::Entity,
+        sender: tokio::sync::mpsc::Sender<crate::pages::Message>,
+    ) -> Command<crate::pages::Message> {
         command::future(fetch_icon_themes()).map(crate::pages::Message::Appearance)
     }
 

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

@@ -207,7 +207,11 @@ impl page::Page<crate::pages::Message> for Page {
             .description(fl!("wallpaper", "desc"))
     }
 
-    fn reload(&mut self, _page: page::Entity) -> Command<crate::pages::Message> {
+    fn on_enter(
+        &mut self,
+        _page: page::Entity,
+        sender: tokio::sync::mpsc::Sender<crate::pages::Message>,
+    ) -> Command<crate::pages::Message> {
         let current_folder = self.config.current_folder().to_owned();
 
         let recurse = self.categories.selected == Some(Category::Wallpapers);

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

@@ -219,12 +219,20 @@ impl page::Page<crate::pages::Message> for Page {
     }
 
     #[cfg(not(feature = "test"))]
-    fn reload(&mut self, _page: page::Entity) -> Command<crate::pages::Message> {
+    fn on_enter(
-        command::future(reload())
+        &mut self,
+        _page: page::Entity,
+        sender: tokio::sync::mpsc::Sender<crate::pages::Message>,
+    ) -> Command<crate::pages::Message> {
+        command::future(on_enter())
     }
 
     #[cfg(feature = "test")]
-    fn reload(&mut self, _page: page::Entity) -> Command<crate::pages::Message> {
+    fn on_enter(
+        &mut self,
+        _page: page::Entity,
+        sender: tokio::sync::mpsc::Sender<crate::pages::Message>,
+    ) -> Command<crate::pages::Message> {
         command::future(async move {
             let mut randr = List::default();
 
@@ -287,7 +295,7 @@ impl Page {
                 }
 
                 return cosmic::command::future(async {
-                    crate::Message::PageMessage(reload().await)
+                    crate::Message::PageMessage(on_enter().await)
                 });
             }
 
@@ -805,7 +813,7 @@ fn cache_rates(cached_rates: &mut Vec<String>, rates: &[u32]) {
         .collect();
 }
 
-pub async fn reload() -> crate::pages::Message {
+pub async fn on_enter() -> crate::pages::Message {
     let graphics_fut = graphics::fetch();
     let randr_fut = cosmic_randr_shell::list();
     let (graphics, randr) = futures::future::zip(graphics_fut, randr_fut).await;

cosmic-settings/src/pages/input/keyboard/mod.rs

@@ -250,7 +250,11 @@ impl page::Page<crate::pages::Message> for Page {
         }
     }
 
-    fn reload(&mut self, _page: page::Entity) -> Command<crate::pages::Message> {
+    fn on_enter(
+        &mut self,
+        _page: page::Entity,
+        sender: tokio::sync::mpsc::Sender<crate::pages::Message>,
+    ) -> Command<crate::pages::Message> {
         self.xkb = super::get_config(&self.config, "xkb_config");
         match xkb_data::keyboard_layouts() {
             Ok(keyboard_layouts) => {

cosmic-settings/src/pages/system/about.rs

@@ -43,7 +43,11 @@ impl page::Page<crate::pages::Message> for Page {
             .description(fl!("about", "desc"))
     }
 
-    fn reload(&mut self, _page: page::Entity) -> Command<crate::pages::Message> {
+    fn on_enter(
+        &mut self,
+        _page: page::Entity,
+        sender: tokio::sync::mpsc::Sender<crate::pages::Message>,
+    ) -> Command<crate::pages::Message> {
         command::future(async move {
             crate::pages::Message::About(Message::Info(Box::new(Info::load())))
         })

page/Cargo.toml

@@ -11,4 +11,5 @@ libcosmic = { workspace = true }
 generator = "0.7.5"
 downcast-rs = "1.2.0"
 once_cell = "1.19.0"
-url = "2.5.0"
+tokio.workspace = true
+url = "2.5.0"

page/src/binder.rs

@@ -166,9 +166,13 @@ impl<Message: 'static> Binder<Message> {
     }
 
     /// Calls a page's load function to refresh its data.
-    pub fn page_reload(&mut self, id: crate::Entity) -> Command<Message> {
+    pub fn on_enter(
+        &mut self,
+        id: crate::Entity,
+        sender: tokio::sync::mpsc::Sender<Message>,
+    ) -> Command<Message> {
         if let Some(page) = self.page.get_mut(id) {
-            return page.reload(id);
+            return page.on_enter(id, sender);
         }
 
         Command::none()

page/src/lib.rs

@@ -59,9 +59,12 @@ pub trait Page<Message: 'static>: Downcast {
     }
 
     /// Reload page metadata via a Command.
-    #[must_use]
     #[allow(unused)]
-    fn reload(&mut self, page: crate::Entity) -> Command<Message> {
+    fn on_enter(
+        &mut self,
+        page: crate::Entity,
+        sender: tokio::sync::mpsc::Sender<Message>,
+    ) -> Command<Message> {
         Command::none()
     }