Don't compute diagnostics on the main thread

closes #2909

Author: matklad

crates/ra_lsp_server/src/main_loop.rs

@@ -9,7 +9,7 @@ use std::{error::Error, fmt, panic, path::PathBuf, sync::Arc, time::Instant};
 
 use crossbeam_channel::{select, unbounded, RecvError, Sender};
 use lsp_server::{Connection, ErrorCode, Message, Notification, Request, RequestId, Response};
-use lsp_types::{ClientCapabilities, NumberOrString, Url};
+use lsp_types::{ClientCapabilities, NumberOrString};
 use ra_cargo_watch::{CheckOptions, CheckTask};
 use ra_ide::{Canceled, FeatureFlags, FileId, LibraryData, SourceRootId};
 use ra_prof::profile;
@@ -352,7 +352,7 @@ fn loop_turn(
             world_state.maybe_collect_garbage();
             loop_state.in_flight_libraries -= 1;
         }
-        Event::CheckWatcher(task) => on_check_task(task, world_state, task_sender)?,
+        Event::CheckWatcher(task) => on_check_task(pool, task, world_state, task_sender)?,
         Event::Msg(msg) => match msg {
             Message::Request(req) => on_request(
                 world_state,
@@ -602,31 +602,23 @@ fn on_notification(
 }
 
 fn on_check_task(
+    pool: &ThreadPool,
     task: CheckTask,
     world_state: &mut WorldState,
     task_sender: &Sender<Task>,
 ) -> Result<()> {
-    match task {
+    let urls = match task {
         CheckTask::ClearDiagnostics => {
             let state = Arc::get_mut(&mut world_state.check_watcher.state)
                 .expect("couldn't get check watcher state as mutable");
-            let cleared_files = state.clear();
-
-            // Send updated diagnostics for each cleared file
-            for url in cleared_files {
-                publish_diagnostics_for_url(&url, world_state, task_sender)?;
-            }
+            state.clear()
         }
 
         CheckTask::AddDiagnostic(url, diagnostic) => {
             let state = Arc::get_mut(&mut world_state.check_watcher.state)
                 .expect("couldn't get check watcher state as mutable");
             state.add_diagnostic_with_fixes(url.clone(), diagnostic);
-
-            // We manually send a diagnostic update when the watcher asks
-            // us to, to avoid the issue of having to change the file to
-            // receive updated diagnostics.
-            publish_diagnostics_for_url(&url, world_state, task_sender)?;
+            vec![url]
         }
 
         CheckTask::Status(progress) => {
@@ -636,22 +628,30 @@ fn on_check_task(
             };
             let not = notification_new::<req::Progress>(params);
             task_sender.send(Task::Notify(not)).unwrap();
+            Vec::new()
         }
-    }
-    Ok(())
-}
+    };
+
+    let subscriptions = urls
+        .into_iter()
+        .map(|url| {
+            let path = url.to_file_path().map_err(|()| format!("invalid uri: {}", url))?;
+            Ok(world_state.vfs.read().path2file(&path).map(|it| FileId(it.0)))
+        })
+        .filter_map(|res| res.transpose())
+        .collect::<Result<Vec<_>>>()?;
+
+    // We manually send a diagnostic update when the watcher asks
+    // us to, to avoid the issue of having to change the file to
+    // receive updated diagnostics.
+    update_file_notifications_on_threadpool(
+        pool,
+        world_state.snapshot(),
+        false,
+        task_sender.clone(),
+        subscriptions,
+    );
 
-fn publish_diagnostics_for_url(
-    url: &Url,
-    world_state: &WorldState,
-    task_sender: &Sender<Task>,
-) -> Result<()> {
-    let path = url.to_file_path().map_err(|()| format!("invalid uri: {}", url))?;
-    if let Some(file_id) = world_state.vfs.read().path2file(&path) {
-        let params = handlers::publish_diagnostics(&world_state.snapshot(), FileId(file_id.0))?;
-        let not = notification_new::<req::PublishDiagnostics>(params);
-        task_sender.send(Task::Notify(not)).unwrap();
-    }
     Ok(())
 }