keep track of state per window

This allows multiple application windows to be opened and managed.

crates/gitbutler-tauri/src/main.rs

@@ -211,14 +211,19 @@ fn main() {
                 .menu(menu::build(tauri_context.package_info()))
                 .on_menu_event(|event|menu::handle_event(&event))
                 .on_window_event(|event| {
-                    if let tauri::WindowEvent::Focused(focused) = event.event() {
-                        if *focused {
-                            tokio::task::spawn(async move {
-                                let _ = event.window().app_handle()
-                                    .state::<WindowState>()
-                                    .flush().await;
-                            });
+                    let window = event.window();
+                    match event.event() {
+                        tauri::WindowEvent::Destroyed  => {
+                            window.app_handle()
+                                .state::<WindowState>()
+                                .remove(window.label());
                         }
+                        tauri::WindowEvent::Focused(focused) if *focused => {
+                            window.app_handle()
+                                .state::<WindowState>()
+                                .flush(window.label()).ok();
+                        },
+                        _ => {}
                     }
                 })
                 .build(tauri_context)

crates/gitbutler-tauri/src/projects.rs

@@ -4,7 +4,7 @@ pub mod commands {
 
     use gitbutler_project::ProjectId;
     use gitbutler_project::{self as projects, Controller};
-    use tauri::State;
+    use tauri::{State, Window};
     use tracing::instrument;
 
     use crate::error::Error;
@@ -49,14 +49,15 @@ pub mod commands {
     ///
     /// We use it to start watching for filesystem events.
     #[tauri::command(async)]
-    #[instrument(skip(controller, watchers), err(Debug))]
+    #[instrument(skip(controller, watchers, window), err(Debug))]
     pub async fn set_project_active(
         controller: State<'_, Controller>,
         watchers: State<'_, WindowState>,
+        window: Window,
         id: ProjectId,
     ) -> Result<(), Error> {
         let project = controller.get(id).context("project not found")?;
-        Ok(watchers.set_project_to_window(&project)?)
+        Ok(watchers.set_project_to_window(window.label(), &project)?)
     }
 
     #[tauri::command(async)]

crates/gitbutler-tauri/src/window.rs

@@ -1,3 +1,4 @@
+use std::collections::BTreeMap;
 use std::sync::Arc;
 
 use anyhow::{Context, Result};
@@ -14,7 +15,7 @@ mod event {
     use gitbutler_watcher::Change;
     use tauri::Manager;
 
-    /// An change we want to inform the frontend about.
+    /// A change we want to inform the frontend about.
     #[derive(Debug, Clone, PartialEq, Eq)]
     pub(super) struct ChangeForFrontend {
         name: String,
@@ -85,18 +86,21 @@ impl Drop for State {
     }
 }
 
+type WindowLabel = String;
+type WindowLabelRef = str;
+
 /// State associated to windows
-/// Note that this type is managed in Tauri and thus needs to be send and sync.
+/// Note that this type is managed in Tauri and thus needs to be `Send` and `Sync`.
 #[derive(Clone)]
 pub struct WindowState {
     /// NOTE: This handle is required for this type to be self-contained as it's used by `core` through a trait.
     app_handle: AppHandle,
-    /// The state for the main window.
+    /// The state for every open application window.
     /// NOTE: This is a `tokio` mutex as this needs to lock the inner option from within async.
-    state: Arc<tokio::sync::Mutex<Option<State>>>,
+    state: Arc<tokio::sync::Mutex<BTreeMap<WindowLabel, State>>>,
 }
 
-fn handler_from_app(app: &AppHandle) -> anyhow::Result<gitbutler_watcher::Handler> {
+fn handler_from_app(app: &AppHandle) -> Result<gitbutler_watcher::Handler> {
     let projects = app.state::<projects::Controller>().inner().clone();
     let users = app.state::<users::Controller>().inner().clone();
     let vbranches = gitbutler_branch_actions::VirtualBranchActions::default();
@@ -120,9 +124,16 @@ impl WindowState {
         }
     }
 
-    /// Watch the project and assure no other instance can access it.
+    /// Watch the `project`, assure no other instance can access it, and associate it with the window
+    /// uniquely identified by `window`.
+    ///
+    /// Previous state will be removed and its resources cleaned up.
     #[instrument(skip(self, project), err(Debug))]
-    pub fn set_project_to_window(&self, project: &projects::Project) -> Result<()> {
+    pub fn set_project_to_window(
+        &self,
+        window: &WindowLabelRef,
+        project: &projects::Project,
+    ) -> Result<()> {
         let mut lock_file =
             fslock::LockFile::open(project.gb_dir().join(WINDOW_LOCK_FILE).as_os_str())?;
         lock_file
@@ -133,20 +144,25 @@ impl WindowState {
         let worktree_dir = project.path.clone();
         let project_id = project.id;
         let watcher = gitbutler_watcher::watch_in_background(handler, worktree_dir, project_id)?;
-        block_on(self.state.lock()).replace(State {
-            project_id,
-            watcher,
-            exclusive_access: lock_file,
-        });
+        let mut state_by_label = block_on(self.state.lock());
+        state_by_label.insert(
+            window.to_owned(),
+            State {
+                project_id,
+                watcher,
+                exclusive_access: lock_file,
+            },
+        );
+        tracing::debug!("Maintaining {} Windows", state_by_label.len());
         Ok(())
     }
 
     pub async fn post(&self, action: gitbutler_watcher::Action) -> Result<()> {
-        let state = self.state.lock().await;
-        if let Some(state) = state
-            .as_ref()
-            .filter(|state| state.project_id == action.project_id())
-        {
+        let mut state_by_label = self.state.lock().await;
+        let state = state_by_label
+            .values_mut()
+            .find(|state| state.project_id == action.project_id());
+        if let Some(state) = state {
             state
                 .watcher
                 .post(action)
@@ -154,19 +170,26 @@ impl WindowState {
                 .context("failed to post event")
         } else {
             Err(anyhow::anyhow!(
-                "matching watcher to post event not found, wanted {wanted}, got {actual:?}",
+                "matching watcher to post event not found, wanted {wanted}",
                 wanted = action.project_id(),
-                actual = state.as_ref().map(|s| s.project_id)
             ))
         }
     }
 
-    pub async fn flush(&self) -> Result<()> {
-        let state = self.state.lock().await;
-        if let Some(state) = state.as_ref() {
+    /// Flush file-monitor watcher events once the windows regains focus for it to respond instantly
+    /// instead of according to the tick-rate.
+    pub fn flush(&self, window: &WindowLabelRef) -> Result<()> {
+        let state_by_label = block_on(self.state.lock());
+        if let Some(state) = state_by_label.get(window) {
             state.watcher.flush()?;
         }
 
         Ok(())
     }
+
+    /// Remove the state associated with `window`, typically upon its destruction.
+    pub fn remove(&self, window: &WindowLabelRef) {
+        let mut state_by_label = block_on(self.state.lock());
+        state_by_label.remove(window);
+    }
 }