Add some documentation around the quit action

fitnesstrax/app/src/main.rs

@@ -34,6 +34,20 @@ const APP_ID_PROD: &str = "com.luminescent-dreams.fitnesstrax";
 
 const RESOURCE_BASE_PATH: &str = "/com/luminescent-dreams/fitnesstrax/";
 
+/// Sets up an application-global action, `app.quit`, which will terminate the application.
+fn setup_app_close_action(app: &adw::Application) {
+    let action = ActionEntry::builder("quit")
+        .activate(|app: &adw::Application, _, _| {
+            // right now, stopping the application is dirt simple. But we could use this
+            // block to add extra code that does additional shutdown steps if we ever want
+            // some states that shouldn't be discarded.
+            app.quit();
+        })
+        .build();
+    app.add_action_entries([action]);
+    app.set_accels_for_action("app.quit", &["<Ctrl>Q"]);
+}
+
 fn main() {
     // I still don't fully understand gio resources. resources_register_include! is convenient
     // because I don't have to deal with filesystem locations at runtime. However, I think other
@@ -67,13 +81,7 @@ fn main() {
         let icon_theme = gtk::IconTheme::for_display(&gdk::Display::default().unwrap());
         icon_theme.add_resource_path(&(RESOURCE_BASE_PATH.to_owned() + "/icons/scalable/actions"));
 
-        let app_close_action = ActionEntry::builder("quit")
+        setup_app_close_action(&adw_app);
-            .activate(|app: &adw::Application, _, _| {
-                app.quit();
-            })
-            .build();
-        adw_app.add_action_entries([app_close_action]);
-        adw_app.set_accels_for_action("app.quit", &["<Ctrl>Q"]);
 
         AppWindow::new(app_id, RESOURCE_BASE_PATH, adw_app, ft_app.clone());
     });