egui: get rid of unnecessary persistence of langid, separate into Config struct

src/bin/topola-egui/app.rs

@@ -16,6 +16,7 @@ use topola::{
 
 use crate::{
     activity::{ActivityStatus, ActivityStepperWithStatus},
+    config::Config,
     error_dialog::ErrorDialog,
     file_receiver::FileReceiver,
     layers::Layers,
@@ -26,52 +27,36 @@ use crate::{
     viewport::Viewport,
 };
 
-/// Deserialize/Serialize is needed to persist app state between restarts.
-#[derive(Serialize, Deserialize)]
-#[serde(default)]
 pub struct App {
+    config: Config,
     translator: Translator,
 
-    #[serde(skip)]
     maybe_overlay: Option<Overlay>,
 
-    #[serde(skip)]
     arc_mutex_maybe_invoker: Arc<Mutex<Option<Invoker<SpecctraMesadata>>>>,
 
-    #[serde(skip)]
     maybe_activity: Option<ActivityStepperWithStatus>,
 
-    #[serde(skip)]
     content_channel: (Sender<String>, Receiver<String>),
-
-    #[serde(skip)]
     history_channel: (Sender<String>, Receiver<String>),
 
-    #[serde(skip)]
     viewport: Viewport,
 
-    #[serde(skip)]
     menu_bar: MenuBar,
-
-    #[serde(skip)]
     status_bar: StatusBar,
 
-    #[serde(skip)]
     error_dialog: ErrorDialog,
 
-    #[serde(skip)]
     maybe_layers: Option<Layers>,
-
-    #[serde(skip)]
     maybe_design: Option<SpecctraDesign>,
 
-    #[serde(skip)]
     update_counter: f32,
 }
 
 impl Default for App {
     fn default() -> Self {
         Self {
+            config: Config::default(),
             translator: Translator::new(langid!("en-US")),
             maybe_overlay: None,
             arc_mutex_maybe_invoker: Arc::new(Mutex::new(None)),
@@ -92,19 +77,15 @@ impl Default for App {
 impl App {
     /// Called once on start.
     pub fn new(cc: &eframe::CreationContext<'_>, langid: LanguageIdentifier) -> Self {
-        // Load previous app state if one exists.
-        if let Some(storage) = cc.storage {
-            let this = Self {
-                translator: Translator::new(langid),
-                ..eframe::get_value(storage, eframe::APP_KEY).unwrap_or_default()
-            };
-            return this;
-        }
-
-        Self {
+        let mut this = Self {
             translator: Translator::new(langid),
             ..Default::default()
+        };
+        // Load previous app state if one exists.
+        if let Some(storage) = cc.storage {
+            this.config = eframe::get_value(storage, eframe::APP_KEY).unwrap_or_default()
         }
+        this
     }
 
     fn advance_state_by_dt(&mut self, dt: f32) {
@@ -196,7 +177,7 @@ impl App {
 impl eframe::App for App {
     /// Called to save state before shutdown.
     fn save(&mut self, storage: &mut dyn eframe::Storage) {
-        eframe::set_value(storage, eframe::APP_KEY, self);
+        eframe::set_value(storage, eframe::APP_KEY, &self.config);
     }
 
     /// Called each time the UI has to be repainted.

src/bin/topola-egui/config.rs

@@ -0,0 +1,10 @@
+#[derive(Clone, Debug, PartialEq, serde::Deserialize, serde::Serialize)]
+#[serde(default)]
+pub struct Config {
+}
+
+impl Default for Config {
+    fn default() -> Self {
+        Self {}
+    }
+}

src/bin/topola-egui/main.rs

@@ -3,6 +3,7 @@
 mod action;
 mod activity;
 mod app;
+mod config;
 mod error_dialog;
 mod file_receiver;
 mod file_sender;
@@ -16,18 +17,19 @@ mod viewport;
 
 use app::App;
 use sys_locale::get_locale;
-use unic_langid::langid;
+use unic_langid::{LanguageIdentifier, langid};
+
+fn get_langid() -> LanguageIdentifier {
+    get_locale()
+        .and_then(|langname| langname.parse().ok())
+        .unwrap_or(langid!("en-US"))
+}
 
 // Build to native.
 #[cfg(not(target_arch = "wasm32"))]
 fn main() -> eframe::Result<()> {
     env_logger::init(); // Log to stderr (if you run with `RUST_LOG=debug`).
-
-    let langid = if let Some(langname) = get_locale() {
-        langname.parse().unwrap_or(langid!("en-US"))
-    } else {
-        langid!("en-US")
-    };
+    let langid = get_langid();
 
     let native_options = eframe::NativeOptions {
         viewport: egui::ViewportBuilder::default()
@@ -49,7 +51,6 @@ fn main() {
 
     // Redirect `log` message to `console.log`:
     eframe::WebLogger::init(log::LevelFilter::Debug).ok();
-
     let web_options = eframe::WebOptions::default();
 
     wasm_bindgen_futures::spawn_local(async {
@@ -64,11 +65,12 @@ fn main() {
             .dyn_into::<eframe::web_sys::HtmlCanvasElement>()
             .expect("topola-egui was not a HtmlCanvasElement");
 
+        let langid = get_langid();
         let start_result = eframe::WebRunner::new()
             .start(
                 canvas,
                 web_options,
-                Box::new(|cc| Ok(Box::new(App::new(cc, langid!("en-US"))))),
+                Box::new(|cc| Ok(Box::new(App::new(cc, langid)))),
             )
             .await;