New option to disable persistent storage (#1825)

* New option to disable persistent storage

crates/re_viewer/src/app.rs

@@ -44,6 +44,7 @@ enum TimeControlCommand {
 #[derive(Clone, Copy, Default)]
 pub struct StartupOptions {
     pub memory_limit: re_memory::MemoryLimit,
+    pub persist_state: bool,
 }
 
 // ----------------------------------------------------------------------------
@@ -118,9 +119,13 @@ impl App {
             );
         }
 
-        let state: AppState = storage
-            .and_then(|storage| eframe::get_value(storage, eframe::APP_KEY))
-            .unwrap_or_default();
+        let state: AppState = if startup_options.persist_state {
+            storage
+                .and_then(|storage| eframe::get_value(storage, eframe::APP_KEY))
+                .unwrap_or_default()
+        } else {
+            AppState::default()
+        };
 
         let mut analytics = ViewerAnalytics::new();
         analytics.on_viewer_started(&build_info, app_env);
@@ -412,7 +417,9 @@ impl eframe::App for App {
     }
 
     fn save(&mut self, storage: &mut dyn eframe::Storage) {
-        eframe::set_value(storage, eframe::APP_KEY, &self.state);
+        if self.startup_options.persist_state {
+            eframe::set_value(storage, eframe::APP_KEY, &self.state);
+        }
     }
 
     fn update(&mut self, egui_ctx: &egui::Context, frame: &mut eframe::Frame) {

crates/re_viewer/src/web.rs

@@ -33,11 +33,13 @@ pub async fn start(
         Box::new(move |cc| {
             let build_info = re_build_info::build_info!();
             let app_env = crate::AppEnvironment::Web;
+            let persist_state = get_persist_state(&cc.integration_info);
             let startup_options = crate::StartupOptions {
                 memory_limit: re_memory::MemoryLimit {
                     // On wasm32 we only have 4GB of memory to play around with.
                     limit: Some(3_500_000_000),
                 },
+                persist_state,
             };
             let re_ui = crate::customize_eframe(cc);
             let url = url.unwrap_or_else(|| get_url(&cc.integration_info));
@@ -122,3 +124,23 @@ fn get_url(info: &eframe::IntegrationInfo) -> String {
         url
     }
 }
+
+fn get_persist_state(info: &eframe::IntegrationInfo) -> bool {
+    match info
+        .web_info
+        .location
+        .query_map
+        .get("persist")
+        .map(String::as_str)
+    {
+        Some("0") => false,
+        Some("1") => true,
+        Some(other) => {
+            re_log::warn!(
+                "Unexpected value for 'persist' query: {other:?}. Expected either '0' or '1'. Defaulting to '1'."
+            );
+            true
+        }
+        _ => true,
+    }
+}

crates/rerun/src/run.rs

@@ -58,6 +58,15 @@ struct Args {
     #[clap(long)]
     memory_limit: Option<String>,
 
+    /// Whether the Rerun Viewer should persist the state of the viewer to disk.
+    ///
+    /// When persisted, the state will be stored at the following locations:
+    /// - Linux: /home/UserName/.local/share/rerunviewer
+    /// - macOS: /Users/UserName/Library/Application Support/rerunviewer
+    /// - Windows: C:\Users\UserName\AppData\Roaming\rerunviewer
+    #[clap(long, default_value_t = true)]
+    persist_state: bool,
+
     /// What TCP port do we listen to (for SDK:s to connect to)?
     #[cfg(feature = "server")]
     #[clap(long, default_value_t = re_sdk_comms::DEFAULT_SERVER_PORT)]
@@ -273,6 +282,7 @@ async fn run_impl(
             re_memory::MemoryLimit::parse(l)
                 .unwrap_or_else(|err| panic!("Bad --memory-limit: {err}"))
         }),
+        persist_state: args.persist_state,
     };
 
     let (shutdown_rx, shutdown_bool) = setup_ctrl_c_handler();