crates/rust-analyzer/src/main_loop.rs

   1 //! The main loop of `rust-analyzer` responsible for dispatching LSP
   2 //! requests/replies and notifications back to the client.
   3 use std::{
   4     env, fmt,
   5     time::{Duration, Instant},
   6 };
   7
   8 use crossbeam_channel::{select, Receiver};
   9 use ide::PrimeCachesProgress;
  10 use ide::{Canceled, FileId};
  11 use ide_db::base_db::VfsPath;
  12 use lsp_server::{Connection, Notification, Request, Response};
  13 use lsp_types::notification::Notification as _;
  14 use vfs::ChangeKind;
  15
  16 use crate::{
  17     config::Config,
  18     dispatch::{NotificationDispatcher, RequestDispatcher},
  19     document::DocumentData,
  20     from_proto,
  21     global_state::{file_id_to_url, url_to_file_id, GlobalState, Status},
  22     handlers, lsp_ext,
  23     lsp_utils::{apply_document_changes, is_canceled, notification_is, Progress},
  24     reload::ProjectWorkspaceProgress,
  25     Result,
  26 };
  27
  28 pub fn main_loop(config: Config, connection: Connection) -> Result<()> {
  29     log::info!("initial config: {:#?}", config);
  30
  31     // Windows scheduler implements priority boosts: if thread waits for an
  32     // event (like a condvar), and event fires, priority of the thread is
  33     // temporary bumped. This optimization backfires in our case: each time the
  34     // `main_loop` schedules a task to run on a threadpool, the worker threads
  35     // gets a higher priority, and (on a machine with fewer cores) displaces the
  36     // main loop! We work-around this by marking the main loop as a
  37     // higher-priority thread.
  38     //
  39     // https://docs.microsoft.com/en-us/windows/win32/procthread/scheduling-priorities
  40     // https://docs.microsoft.com/en-us/windows/win32/procthread/priority-boosts
  41     // https://github.com/rust-analyzer/rust-analyzer/issues/2835
  42     #[cfg(windows)]
  43     unsafe {
  44         use winapi::um::processthreadsapi::*;
  45         let thread = GetCurrentThread();
  46         let thread_priority_above_normal = 1;
  47         SetThreadPriority(thread, thread_priority_above_normal);
  48     }
  49
  50     GlobalState::new(connection.sender, config).run(connection.receiver)
  51 }
  52
  53 enum Event {
  54     Lsp(lsp_server::Message),
  55     Task(Task),
  56     Vfs(vfs::loader::Message),
  57     Flycheck(flycheck::Message),
  58 }
  59
  60 #[derive(Debug)]
  61 pub(crate) enum Task {
  62     Response(Response),
  63     Diagnostics(Vec<(FileId, Vec<lsp_types::Diagnostic>)>),
  64     PrimeCaches(PrimeCachesProgress),
  65     FetchWorkspace(ProjectWorkspaceProgress),
  66 }
  67
  68 impl fmt::Debug for Event {
  69     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
  70         let debug_verbose_not = |not: &Notification, f: &mut fmt::Formatter| {
  71             f.debug_struct("Notification").field("method", &not.method).finish()
  72         };
  73
  74         match self {
  75             Event::Lsp(lsp_server::Message::Notification(not)) => {
  76                 if notification_is::<lsp_types::notification::DidOpenTextDocument>(not)
  77                     || notification_is::<lsp_types::notification::DidChangeTextDocument>(not)
  78                 {
  79                     return debug_verbose_not(not, f);
  80                 }
  81             }
  82             Event::Task(Task::Response(resp)) => {
  83                 return f
  84                     .debug_struct("Response")
  85                     .field("id", &resp.id)
  86                     .field("error", &resp.error)
  87                     .finish();
  88             }
  89             _ => (),
  90         }
  91         match self {
  92             Event::Lsp(it) => fmt::Debug::fmt(it, f),
  93             Event::Task(it) => fmt::Debug::fmt(it, f),
  94             Event::Vfs(it) => fmt::Debug::fmt(it, f),
  95             Event::Flycheck(it) => fmt::Debug::fmt(it, f),
  96         }
  97     }
  98 }
  99
 100 impl GlobalState {
 101     fn run(mut self, inbox: Receiver<lsp_server::Message>) -> Result<()> {
 102         if self.config.linked_projects().is_empty()
 103             && self.config.notifications().cargo_toml_not_found
 104         {
 105             self.show_message(
 106                 lsp_types::MessageType::Error,
 107                 "rust-analyzer failed to discover workspace".to_string(),
 108             );
 109         };
 110
 111         if self.config.did_save_text_document_dynamic_registration() {
 112             let save_registration_options = lsp_types::TextDocumentSaveRegistrationOptions {
 113                 include_text: Some(false),
 114                 text_document_registration_options: lsp_types::TextDocumentRegistrationOptions {
 115                     document_selector: Some(vec![
 116                         lsp_types::DocumentFilter {
 117                             language: None,
 118                             scheme: None,
 119                             pattern: Some("**/*.rs".into()),
 120                         },
 121                         lsp_types::DocumentFilter {
 122                             language: None,
 123                             scheme: None,
 124                             pattern: Some("**/Cargo.toml".into()),
 125                         },
 126                         lsp_types::DocumentFilter {
 127                             language: None,
 128                             scheme: None,
 129                             pattern: Some("**/Cargo.lock".into()),
 130                         },
 131                     ]),
 132                 },
 133             };
 134
 135             let registration = lsp_types::Registration {
 136                 id: "textDocument/didSave".to_string(),
 137                 method: "textDocument/didSave".to_string(),
 138                 register_options: Some(serde_json::to_value(save_registration_options).unwrap()),
 139             };
 140             self.send_request::<lsp_types::request::RegisterCapability>(
 141                 lsp_types::RegistrationParams { registrations: vec![registration] },
 142                 |_, _| (),
 143             );
 144         }
 145
 146         self.fetch_workspaces_request();
 147         self.fetch_workspaces_if_needed();
 148
 149         while let Some(event) = self.next_event(&inbox) {
 150             if let Event::Lsp(lsp_server::Message::Notification(not)) = &event {
 151                 if not.method == lsp_types::notification::Exit::METHOD {
 152                     return Ok(());
 153                 }
 154             }
 155             self.handle_event(event)?
 156         }
 157
 158         Err("client exited without proper shutdown sequence")?
 159     }
 160
 161     fn next_event(&self, inbox: &Receiver<lsp_server::Message>) -> Option<Event> {
 162         select! {
 163             recv(inbox) -> msg =>
 164                 msg.ok().map(Event::Lsp),
 165
 166             recv(self.task_pool.receiver) -> task =>
 167                 Some(Event::Task(task.unwrap())),
 168
 169             recv(self.loader.receiver) -> task =>
 170                 Some(Event::Vfs(task.unwrap())),
 171
 172             recv(self.flycheck_receiver) -> task =>
 173                 Some(Event::Flycheck(task.unwrap())),
 174         }
 175     }
 176
 177     fn handle_event(&mut self, event: Event) -> Result<()> {
 178         let loop_start = Instant::now();
 179         // NOTE: don't count blocking select! call as a loop-turn time
 180         let _p = profile::span("GlobalState::handle_event");
 181
 182         log::info!("handle_event({:?})", event);
 183         let task_queue_len = self.task_pool.handle.len();
 184         if task_queue_len > 0 {
 185             log::info!("task queue len: {}", task_queue_len);
 186         }
 187
 188         let prev_status = self.status;
 189         match event {
 190             Event::Lsp(msg) => match msg {
 191                 lsp_server::Message::Request(req) => self.on_request(loop_start, req)?,
 192                 lsp_server::Message::Notification(not) => {
 193                     self.on_notification(not)?;
 194                 }
 195                 lsp_server::Message::Response(resp) => self.complete_request(resp),
 196             },
 197             Event::Task(mut task) => {
 198                 let _p = profile::span("GlobalState::handle_event/task");
 199                 let mut prime_caches_progress = Vec::new();
 200                 loop {
 201                     match task {
 202                         Task::Response(response) => self.respond(response),
 203                         Task::Diagnostics(diagnostics_per_file) => {
 204                             for (file_id, diagnostics) in diagnostics_per_file {
 205                                 self.diagnostics.set_native_diagnostics(file_id, diagnostics)
 206                             }
 207                         }
 208                         Task::PrimeCaches(progress) => match progress {
 209                             PrimeCachesProgress::Started => prime_caches_progress.push(progress),
 210                             PrimeCachesProgress::StartedOnCrate { .. } => {
 211                                 match prime_caches_progress.last_mut() {
 212                                     Some(last @ PrimeCachesProgress::StartedOnCrate { .. }) => {
 213                                         // Coalesce subsequent update events.
 214                                         *last = progress;
 215                                     }
 216                                     _ => prime_caches_progress.push(progress),
 217                                 }
 218                             }
 219                             PrimeCachesProgress::Finished => prime_caches_progress.push(progress),
 220                         },
 221                         Task::FetchWorkspace(progress) => {
 222                             let (state, msg) = match progress {
 223                                 ProjectWorkspaceProgress::Begin => (Progress::Begin, None),
 224                                 ProjectWorkspaceProgress::Report(msg) => {
 225                                     (Progress::Report, Some(msg))
 226                                 }
 227                                 ProjectWorkspaceProgress::End(workspaces) => {
 228                                     self.fetch_workspaces_completed();
 229                                     self.switch_workspaces(workspaces);
 230                                     (Progress::End, None)
 231                                 }
 232                             };
 233                             self.report_progress("fetching", state, msg, None);
 234                         }
 235                     }
 236                     // Coalesce multiple task events into one loop turn
 237                     task = match self.task_pool.receiver.try_recv() {
 238                         Ok(task) => task,
 239                         Err(_) => break,
 240                     };
 241                 }
 242
 243                 for progress in prime_caches_progress {
 244                     let (state, message, fraction);
 245                     match progress {
 246                         PrimeCachesProgress::Started => {
 247                             state = Progress::Begin;
 248                             message = None;
 249                             fraction = 0.0;
 250                         }
 251                         PrimeCachesProgress::StartedOnCrate { on_crate, n_done, n_total } => {
 252                             state = Progress::Report;
 253                             message = Some(format!("{}/{} ({})", n_done, n_total, on_crate));
 254                             fraction = Progress::fraction(n_done, n_total);
 255                         }
 256                         PrimeCachesProgress::Finished => {
 257                             state = Progress::End;
 258                             message = None;
 259                             fraction = 1.0;
 260                         }
 261                     };
 262
 263                     self.report_progress("indexing", state, message, Some(fraction));
 264                 }
 265             }
 266             Event::Vfs(mut task) => {
 267                 let _p = profile::span("GlobalState::handle_event/vfs");
 268                 loop {
 269                     match task {
 270                         vfs::loader::Message::Loaded { files } => {
 271                             let vfs = &mut self.vfs.write().0;
 272                             for (path, contents) in files {
 273                                 let path = VfsPath::from(path);
 274                                 if !self.mem_docs.contains_key(&path) {
 275                                     vfs.set_file_contents(path, contents);
 276                                 }
 277                             }
 278                         }
 279                         vfs::loader::Message::Progress { n_total, n_done } => {
 280                             if n_total == 0 {
 281                                 self.transition(Status::Invalid);
 282                             } else {
 283                                 let state = if n_done == 0 {
 284                                     self.transition(Status::Loading);
 285                                     Progress::Begin
 286                                 } else if n_done < n_total {
 287                                     Progress::Report
 288                                 } else {
 289                                     assert_eq!(n_done, n_total);
 290                                     self.transition(Status::Ready);
 291                                     Progress::End
 292                                 };
 293                                 self.report_progress(
 294                                     "roots scanned",
 295                                     state,
 296                                     Some(format!("{}/{}", n_done, n_total)),
 297                                     Some(Progress::fraction(n_done, n_total)),
 298                                 )
 299                             }
 300                         }
 301                     }
 302                     // Coalesce many VFS event into a single loop turn
 303                     task = match self.loader.receiver.try_recv() {
 304                         Ok(task) => task,
 305                         Err(_) => break,
 306                     }
 307                 }
 308             }
 309             Event::Flycheck(mut task) => {
 310                 let _p = profile::span("GlobalState::handle_event/flycheck");
 311                 loop {
 312                     match task {
 313                         flycheck::Message::AddDiagnostic { workspace_root, diagnostic } => {
 314                             let diagnostics =
 315                                 crate::diagnostics::to_proto::map_rust_diagnostic_to_lsp(
 316                                     &self.config.diagnostics_map(),
 317                                     &diagnostic,
 318                                     &workspace_root,
 319                                 );
 320                             for diag in diagnostics {
 321                                 match url_to_file_id(&self.vfs.read().0, &diag.url) {
 322                                     Ok(file_id) => self.diagnostics.add_check_diagnostic(
 323                                         file_id,
 324                                         diag.diagnostic,
 325                                         diag.fixes,
 326                                     ),
 327                                     Err(err) => {
 328                                         log::error!(
 329                                             "File with cargo diagnostic not found in VFS: {}",
 330                                             err
 331                                         );
 332                                     }
 333                                 };
 334                             }
 335                         }
 336
 337                         flycheck::Message::Progress { id, progress } => {
 338                             let (state, message) = match progress {
 339                                 flycheck::Progress::DidStart => {
 340                                     self.diagnostics.clear_check();
 341                                     (Progress::Begin, None)
 342                                 }
 343                                 flycheck::Progress::DidCheckCrate(target) => {
 344                                     (Progress::Report, Some(target))
 345                                 }
 346                                 flycheck::Progress::DidCancel => (Progress::End, None),
 347                                 flycheck::Progress::DidFinish(result) => {
 348                                     if let Err(err) = result {
 349                                         log::error!("cargo check failed: {}", err)
 350                                     }
 351                                     (Progress::End, None)
 352                                 }
 353                             };
 354
 355                             // When we're running multiple flychecks, we have to include a disambiguator in
 356                             // the title, or the editor complains. Note that this is a user-facing string.
 357                             let title = if self.flycheck.len() == 1 {
 358                                 "cargo check".to_string()
 359                             } else {
 360                                 format!("cargo check (#{})", id + 1)
 361                             };
 362                             self.report_progress(&title, state, message, None);
 363                         }
 364                     }
 365                     // Coalesce many flycheck updates into a single loop turn
 366                     task = match self.flycheck_receiver.try_recv() {
 367                         Ok(task) => task,
 368                         Err(_) => break,
 369                     }
 370                 }
 371             }
 372         }
 373
 374         let state_changed = self.process_changes();
 375         if prev_status == Status::Loading && self.status == Status::Ready {
 376             for flycheck in &self.flycheck {
 377                 flycheck.update();
 378             }
 379         }
 380
 381         if self.status == Status::Ready && (state_changed || prev_status == Status::Loading) {
 382             self.update_file_notifications_on_threadpool();
 383
 384             // Refresh semantic tokens if the client supports it.
 385             if self.config.semantic_tokens_refresh() {
 386                 self.semantic_tokens_cache.lock().clear();
 387                 self.send_request::<lsp_types::request::SemanticTokensRefesh>((), |_, _| ());
 388             }
 389
 390             // Refresh code lens if the client supports it.
 391             if self.config.code_lens_refresh() {
 392                 self.send_request::<lsp_types::request::CodeLensRefresh>((), |_, _| ());
 393             }
 394         }
 395
 396         if let Some(diagnostic_changes) = self.diagnostics.take_changes() {
 397             for file_id in diagnostic_changes {
 398                 let url = file_id_to_url(&self.vfs.read().0, file_id);
 399                 let diagnostics = self.diagnostics.diagnostics_for(file_id).cloned().collect();
 400                 let version = from_proto::vfs_path(&url)
 401                     .map(|path| self.mem_docs.get(&path).map(|it| it.version))
 402                     .unwrap_or_default();
 403
 404                 self.send_notification::<lsp_types::notification::PublishDiagnostics>(
 405                     lsp_types::PublishDiagnosticsParams { uri: url, diagnostics, version },
 406                 );
 407             }
 408         }
 409
 410         self.fetch_workspaces_if_needed();
 411
 412         let loop_duration = loop_start.elapsed();
 413         if loop_duration > Duration::from_millis(100) {
 414             log::warn!("overly long loop turn: {:?}", loop_duration);
 415             if env::var("RA_PROFILE").is_ok() {
 416                 self.show_message(
 417                     lsp_types::MessageType::Error,
 418                     format!("overly long loop turn: {:?}", loop_duration),
 419                 )
 420             }
 421         }
 422         Ok(())
 423     }
 424
 425     fn on_request(&mut self, request_received: Instant, req: Request) -> Result<()> {
 426         self.register_request(&req, request_received);
 427
 428         if self.shutdown_requested {
 429             self.respond(Response::new_err(
 430                 req.id,
 431                 lsp_server::ErrorCode::InvalidRequest as i32,
 432                 "Shutdown already requested.".to_owned(),
 433             ));
 434
 435             return Ok(());
 436         }
 437
 438         if self.status == Status::Loading && req.method != "shutdown" {
 439             self.respond(lsp_server::Response::new_err(
 440                 req.id,
 441                 // FIXME: i32 should impl From<ErrorCode> (from() guarantees lossless conversion)
 442                 lsp_server::ErrorCode::ContentModified as i32,
 443                 "Rust Analyzer is still loading...".to_owned(),
 444             ));
 445             return Ok(());
 446         }
 447
 448         RequestDispatcher { req: Some(req), global_state: self }
 449             .on_sync::<lsp_ext::ReloadWorkspace>(|s, ()| Ok(s.fetch_workspaces_request()))?
 450             .on_sync::<lsp_ext::JoinLines>(|s, p| handlers::handle_join_lines(s.snapshot(), p))?
 451             .on_sync::<lsp_ext::OnEnter>(|s, p| handlers::handle_on_enter(s.snapshot(), p))?
 452             .on_sync::<lsp_types::request::Shutdown>(|s, ()| {
 453                 s.shutdown_requested = true;
 454                 Ok(())
 455             })?
 456             .on_sync::<lsp_types::request::SelectionRangeRequest>(|s, p| {
 457                 handlers::handle_selection_range(s.snapshot(), p)
 458             })?
 459             .on_sync::<lsp_ext::MatchingBrace>(|s, p| {
 460                 handlers::handle_matching_brace(s.snapshot(), p)
 461             })?
 462             .on_sync::<lsp_ext::MemoryUsage>(|s, p| handlers::handle_memory_usage(s, p))?
 463             .on::<lsp_ext::AnalyzerStatus>(handlers::handle_analyzer_status)
 464             .on::<lsp_ext::SyntaxTree>(handlers::handle_syntax_tree)
 465             .on::<lsp_ext::ViewHir>(handlers::handle_view_hir)
 466             .on::<lsp_ext::ExpandMacro>(handlers::handle_expand_macro)
 467             .on::<lsp_ext::ParentModule>(handlers::handle_parent_module)
 468             .on::<lsp_ext::Runnables>(handlers::handle_runnables)
 469             .on::<lsp_ext::InlayHints>(handlers::handle_inlay_hints)
 470             .on::<lsp_ext::CodeActionRequest>(handlers::handle_code_action)
 471             .on::<lsp_ext::CodeActionResolveRequest>(handlers::handle_code_action_resolve)
 472             .on::<lsp_ext::HoverRequest>(handlers::handle_hover)
 473             .on::<lsp_ext::ExternalDocs>(handlers::handle_open_docs)
 474             .on::<lsp_ext::OpenCargoToml>(handlers::handle_open_cargo_toml)
 475             .on::<lsp_types::request::OnTypeFormatting>(handlers::handle_on_type_formatting)
 476             .on::<lsp_types::request::DocumentSymbolRequest>(handlers::handle_document_symbol)
 477             .on::<lsp_types::request::WorkspaceSymbol>(handlers::handle_workspace_symbol)
 478             .on::<lsp_types::request::GotoDefinition>(handlers::handle_goto_definition)
 479             .on::<lsp_types::request::GotoImplementation>(handlers::handle_goto_implementation)
 480             .on::<lsp_types::request::GotoTypeDefinition>(handlers::handle_goto_type_definition)
 481             .on::<lsp_types::request::Completion>(handlers::handle_completion)
 482             .on::<lsp_types::request::ResolveCompletionItem>(handlers::handle_completion_resolve)
 483             .on::<lsp_types::request::CodeLensRequest>(handlers::handle_code_lens)
 484             .on::<lsp_types::request::CodeLensResolve>(handlers::handle_code_lens_resolve)
 485             .on::<lsp_types::request::FoldingRangeRequest>(handlers::handle_folding_range)
 486             .on::<lsp_types::request::SignatureHelpRequest>(handlers::handle_signature_help)
 487             .on::<lsp_types::request::PrepareRenameRequest>(handlers::handle_prepare_rename)
 488             .on::<lsp_types::request::Rename>(handlers::handle_rename)
 489             .on::<lsp_types::request::References>(handlers::handle_references)
 490             .on::<lsp_types::request::Formatting>(handlers::handle_formatting)
 491             .on::<lsp_types::request::DocumentHighlightRequest>(handlers::handle_document_highlight)
 492             .on::<lsp_types::request::CallHierarchyPrepare>(handlers::handle_call_hierarchy_prepare)
 493             .on::<lsp_types::request::CallHierarchyIncomingCalls>(
 494                 handlers::handle_call_hierarchy_incoming,
 495             )
 496             .on::<lsp_types::request::CallHierarchyOutgoingCalls>(
 497                 handlers::handle_call_hierarchy_outgoing,
 498             )
 499             .on::<lsp_types::request::SemanticTokensFullRequest>(
 500                 handlers::handle_semantic_tokens_full,
 501             )
 502             .on::<lsp_types::request::SemanticTokensFullDeltaRequest>(
 503                 handlers::handle_semantic_tokens_full_delta,
 504             )
 505             .on::<lsp_types::request::SemanticTokensRangeRequest>(
 506                 handlers::handle_semantic_tokens_range,
 507             )
 508             .on::<lsp_types::request::WillRenameFiles>(handlers::handle_will_rename_files)
 509             .on::<lsp_ext::Ssr>(handlers::handle_ssr)
 510             .finish();
 511         Ok(())
 512     }
 513     fn on_notification(&mut self, not: Notification) -> Result<()> {
 514         NotificationDispatcher { not: Some(not), global_state: self }
 515             .on::<lsp_types::notification::Cancel>(|this, params| {
 516                 let id: lsp_server::RequestId = match params.id {
 517                     lsp_types::NumberOrString::Number(id) => id.into(),
 518                     lsp_types::NumberOrString::String(id) => id.into(),
 519                 };
 520                 this.cancel(id);
 521                 Ok(())
 522             })?
 523             .on::<lsp_types::notification::DidOpenTextDocument>(|this, params| {
 524                 if let Ok(path) = from_proto::vfs_path(&params.text_document.uri) {
 525                     if this
 526                         .mem_docs
 527                         .insert(path.clone(), DocumentData::new(params.text_document.version))
 528                         .is_some()
 529                     {
 530                         log::error!("duplicate DidOpenTextDocument: {}", path)
 531                     }
 532                     let changed = this
 533                         .vfs
 534                         .write()
 535                         .0
 536                         .set_file_contents(path, Some(params.text_document.text.into_bytes()));
 537
 538                     // If the VFS contents are unchanged, update diagnostics, since `handle_event`
 539                     // won't see any changes. This avoids missing diagnostics when opening a file.
 540                     //
 541                     // If the file *was* changed, `handle_event` will already recompute and send
 542                     // diagnostics. We can't do it here, since the *current* file contents might be
 543                     // unset in salsa, since the VFS change hasn't been applied to the database yet.
 544                     if !changed {
 545                         this.maybe_update_diagnostics();
 546                     }
 547                 }
 548                 Ok(())
 549             })?
 550             .on::<lsp_types::notification::DidChangeTextDocument>(|this, params| {
 551                 if let Ok(path) = from_proto::vfs_path(&params.text_document.uri) {
 552                     let doc = match this.mem_docs.get_mut(&path) {
 553                         Some(doc) => doc,
 554                         None => {
 555                             log::error!("expected DidChangeTextDocument: {}", path);
 556                             return Ok(());
 557                         }
 558                     };
 559                     let vfs = &mut this.vfs.write().0;
 560                     let file_id = vfs.file_id(&path).unwrap();
 561                     let mut text = String::from_utf8(vfs.file_contents(file_id).to_vec()).unwrap();
 562                     apply_document_changes(&mut text, params.content_changes);
 563
 564                     // The version passed in DidChangeTextDocument is the version after all edits are applied
 565                     // so we should apply it before the vfs is notified.
 566                     doc.version = params.text_document.version;
 567
 568                     vfs.set_file_contents(path.clone(), Some(text.into_bytes()));
 569                 }
 570                 Ok(())
 571             })?
 572             .on::<lsp_types::notification::DidCloseTextDocument>(|this, params| {
 573                 let mut version = None;
 574                 if let Ok(path) = from_proto::vfs_path(&params.text_document.uri) {
 575                     match this.mem_docs.remove(&path) {
 576                         Some(doc) => version = Some(doc.version),
 577                         None => log::error!("orphan DidCloseTextDocument: {}", path),
 578                     }
 579
 580                     this.semantic_tokens_cache.lock().remove(&params.text_document.uri);
 581
 582                     if let Some(path) = path.as_path() {
 583                         this.loader.handle.invalidate(path.to_path_buf());
 584                     }
 585                 }
 586
 587                 // Clear the diagnostics for the previously known version of the file.
 588                 // This prevents stale "cargo check" diagnostics if the file is
 589                 // closed, "cargo check" is run and then the file is reopened.
 590                 this.send_notification::<lsp_types::notification::PublishDiagnostics>(
 591                     lsp_types::PublishDiagnosticsParams {
 592                         uri: params.text_document.uri,
 593                         diagnostics: Vec::new(),
 594                         version,
 595                     },
 596                 );
 597                 Ok(())
 598             })?
 599             .on::<lsp_types::notification::DidSaveTextDocument>(|this, params| {
 600                 for flycheck in &this.flycheck {
 601                     flycheck.update();
 602                 }
 603                 if let Ok(abs_path) = from_proto::abs_path(&params.text_document.uri) {
 604                     this.maybe_refresh(&[(abs_path, ChangeKind::Modify)]);
 605                 }
 606                 Ok(())
 607             })?
 608             .on::<lsp_types::notification::DidChangeConfiguration>(|this, _params| {
 609                 // As stated in https://github.com/microsoft/language-server-protocol/issues/676,
 610                 // this notification's parameters should be ignored and the actual config queried separately.
 611                 this.send_request::<lsp_types::request::WorkspaceConfiguration>(
 612                     lsp_types::ConfigurationParams {
 613                         items: vec![lsp_types::ConfigurationItem {
 614                             scope_uri: None,
 615                             section: Some("rust-analyzer".to_string()),
 616                         }],
 617                     },
 618                     |this, resp| {
 619                         log::debug!("config update response: '{:?}", resp);
 620                         let Response { error, result, .. } = resp;
 621
 622                         match (error, result) {
 623                             (Some(err), _) => {
 624                                 log::error!("failed to fetch the server settings: {:?}", err)
 625                             }
 626                             (None, Some(mut configs)) => {
 627                                 if let Some(json) = configs.get_mut(0) {
 628                                     // Note that json can be null according to the spec if the client can't
 629                                     // provide a configuration. This is handled in Config::update below.
 630                                     let mut config = Config::clone(&*this.config);
 631                                     config.update(json.take());
 632                                     this.update_configuration(config);
 633                                 }
 634                             }
 635                             (None, None) => log::error!(
 636                                 "received empty server settings response from the client"
 637                             ),
 638                         }
 639                     },
 640                 );
 641
 642                 return Ok(());
 643             })?
 644             .on::<lsp_types::notification::DidChangeWatchedFiles>(|this, params| {
 645                 for change in params.changes {
 646                     if let Ok(path) = from_proto::abs_path(&change.uri) {
 647                         this.loader.handle.invalidate(path);
 648                     }
 649                 }
 650                 Ok(())
 651             })?
 652             .finish();
 653         Ok(())
 654     }
 655     fn update_file_notifications_on_threadpool(&mut self) {
 656         self.maybe_update_diagnostics();
 657         self.task_pool.handle.spawn_with_sender({
 658             let snap = self.snapshot();
 659             move |sender| {
 660                 snap.analysis
 661                     .prime_caches(|progress| {
 662                         sender.send(Task::PrimeCaches(progress)).unwrap();
 663                     })
 664                     .unwrap_or_else(|_: Canceled| {
 665                         // Pretend that we're done, so that the progress bar is removed. Otherwise
 666                         // the editor may complain about it already existing.
 667                         sender.send(Task::PrimeCaches(PrimeCachesProgress::Finished)).unwrap()
 668                     });
 669             }
 670         });
 671     }
 672     fn maybe_update_diagnostics(&mut self) {
 673         let subscriptions = self
 674             .mem_docs
 675             .keys()
 676             .map(|path| self.vfs.read().0.file_id(&path).unwrap())
 677             .collect::<Vec<_>>();
 678
 679         log::trace!("updating notifications for {:?}", subscriptions);
 680         if self.config.publish_diagnostics() {
 681             let snapshot = self.snapshot();
 682             self.task_pool.handle.spawn(move || {
 683                 let diagnostics = subscriptions
 684                     .into_iter()
 685                     .filter_map(|file_id| {
 686                         handlers::publish_diagnostics(&snapshot, file_id)
 687                             .map_err(|err| {
 688                                 if !is_canceled(&*err) {
 689                                     log::error!("failed to compute diagnostics: {:?}", err);
 690                                 }
 691                                 ()
 692                             })
 693                             .ok()
 694                             .map(|diags| (file_id, diags))
 695                     })
 696                     .collect::<Vec<_>>();
 697                 Task::Diagnostics(diagnostics)
 698             })
 699         }
 700     }
 701 }