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     sync::Arc,
   6     time::{Duration, Instant},
   7 };
   8
   9 use always_assert::always;
  10 use crossbeam_channel::{select, Receiver};
  11 use ide::{FileId, PrimeCachesProgress};
  12 use ide_db::base_db::VfsPath;
  13 use lsp_server::{Connection, Notification, Request, Response};
  14 use lsp_types::notification::Notification as _;
  15 use project_model::BuildDataCollector;
  16 use vfs::ChangeKind;
  17
  18 use crate::{
  19     config::Config,
  20     dispatch::{NotificationDispatcher, RequestDispatcher},
  21     document::DocumentData,
  22     from_proto,
  23     global_state::{file_id_to_url, url_to_file_id, GlobalState},
  24     handlers, lsp_ext,
  25     lsp_utils::{apply_document_changes, is_cancelled, notification_is, Progress},
  26     reload::{BuildDataProgress, ProjectWorkspaceProgress},
  27     Result,
  28 };
  29
  30 pub fn main_loop(config: Config, connection: Connection) -> Result<()> {
  31     log::info!("initial config: {:#?}", config);
  32
  33     // Windows scheduler implements priority boosts: if thread waits for an
  34     // event (like a condvar), and event fires, priority of the thread is
  35     // temporary bumped. This optimization backfires in our case: each time the
  36     // `main_loop` schedules a task to run on a threadpool, the worker threads
  37     // gets a higher priority, and (on a machine with fewer cores) displaces the
  38     // main loop! We work-around this by marking the main loop as a
  39     // higher-priority thread.
  40     //
  41     // https://docs.microsoft.com/en-us/windows/win32/procthread/scheduling-priorities
  42     // https://docs.microsoft.com/en-us/windows/win32/procthread/priority-boosts
  43     // https://github.com/rust-analyzer/rust-analyzer/issues/2835
  44     #[cfg(windows)]
  45     unsafe {
  46         use winapi::um::processthreadsapi::*;
  47         let thread = GetCurrentThread();
  48         let thread_priority_above_normal = 1;
  49         SetThreadPriority(thread, thread_priority_above_normal);
  50     }
  51
  52     GlobalState::new(connection.sender, config).run(connection.receiver)
  53 }
  54
  55 enum Event {
  56     Lsp(lsp_server::Message),
  57     Task(Task),
  58     Vfs(vfs::loader::Message),
  59     Flycheck(flycheck::Message),
  60 }
  61
  62 #[derive(Debug)]
  63 pub(crate) enum Task {
  64     Response(Response),
  65     Diagnostics(Vec<(FileId, Vec<lsp_types::Diagnostic>)>),
  66     PrimeCaches(PrimeCachesProgress),
  67     FetchWorkspace(ProjectWorkspaceProgress),
  68     FetchBuildData(BuildDataProgress),
  69 }
  70
  71 impl fmt::Debug for Event {
  72     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
  73         let debug_verbose_not = |not: &Notification, f: &mut fmt::Formatter| {
  74             f.debug_struct("Notification").field("method", &not.method).finish()
  75         };
  76
  77         match self {
  78             Event::Lsp(lsp_server::Message::Notification(not)) => {
  79                 if notification_is::<lsp_types::notification::DidOpenTextDocument>(not)
  80                     || notification_is::<lsp_types::notification::DidChangeTextDocument>(not)
  81                 {
  82                     return debug_verbose_not(not, f);
  83                 }
  84             }
  85             Event::Task(Task::Response(resp)) => {
  86                 return f
  87                     .debug_struct("Response")
  88                     .field("id", &resp.id)
  89                     .field("error", &resp.error)
  90                     .finish();
  91             }
  92             _ => (),
  93         }
  94         match self {
  95             Event::Lsp(it) => fmt::Debug::fmt(it, f),
  96             Event::Task(it) => fmt::Debug::fmt(it, f),
  97             Event::Vfs(it) => fmt::Debug::fmt(it, f),
  98             Event::Flycheck(it) => fmt::Debug::fmt(it, f),
  99         }
 100     }
 101 }
 102
 103 impl GlobalState {
 104     fn run(mut self, inbox: Receiver<lsp_server::Message>) -> Result<()> {
 105         if self.config.linked_projects().is_empty()
 106             && self.config.detached_files().is_empty()
 107             && self.config.notifications().cargo_toml_not_found
 108         {
 109             self.show_message(
 110                 lsp_types::MessageType::Error,
 111                 "rust-analyzer failed to discover workspace".to_string(),
 112             );
 113         };
 114
 115         if self.config.did_save_text_document_dynamic_registration() {
 116             let save_registration_options = lsp_types::TextDocumentSaveRegistrationOptions {
 117                 include_text: Some(false),
 118                 text_document_registration_options: lsp_types::TextDocumentRegistrationOptions {
 119                     document_selector: Some(vec![
 120                         lsp_types::DocumentFilter {
 121                             language: None,
 122                             scheme: None,
 123                             pattern: Some("**/*.rs".into()),
 124                         },
 125                         lsp_types::DocumentFilter {
 126                             language: None,
 127                             scheme: None,
 128                             pattern: Some("**/Cargo.toml".into()),
 129                         },
 130                         lsp_types::DocumentFilter {
 131                             language: None,
 132                             scheme: None,
 133                             pattern: Some("**/Cargo.lock".into()),
 134                         },
 135                     ]),
 136                 },
 137             };
 138
 139             let registration = lsp_types::Registration {
 140                 id: "textDocument/didSave".to_string(),
 141                 method: "textDocument/didSave".to_string(),
 142                 register_options: Some(serde_json::to_value(save_registration_options).unwrap()),
 143             };
 144             self.send_request::<lsp_types::request::RegisterCapability>(
 145                 lsp_types::RegistrationParams { registrations: vec![registration] },
 146                 |_, _| (),
 147             );
 148         }
 149
 150         self.fetch_workspaces_request();
 151         self.fetch_workspaces_if_needed();
 152
 153         while let Some(event) = self.next_event(&inbox) {
 154             if let Event::Lsp(lsp_server::Message::Notification(not)) = &event {
 155                 if not.method == lsp_types::notification::Exit::METHOD {
 156                     return Ok(());
 157                 }
 158             }
 159             self.handle_event(event)?
 160         }
 161
 162         Err("client exited without proper shutdown sequence")?
 163     }
 164
 165     fn next_event(&self, inbox: &Receiver<lsp_server::Message>) -> Option<Event> {
 166         select! {
 167             recv(inbox) -> msg =>
 168                 msg.ok().map(Event::Lsp),
 169
 170             recv(self.task_pool.receiver) -> task =>
 171                 Some(Event::Task(task.unwrap())),
 172
 173             recv(self.loader.receiver) -> task =>
 174                 Some(Event::Vfs(task.unwrap())),
 175
 176             recv(self.flycheck_receiver) -> task =>
 177                 Some(Event::Flycheck(task.unwrap())),
 178         }
 179     }
 180
 181     fn handle_event(&mut self, event: Event) -> Result<()> {
 182         let loop_start = Instant::now();
 183         // NOTE: don't count blocking select! call as a loop-turn time
 184         let _p = profile::span("GlobalState::handle_event");
 185
 186         log::info!("handle_event({:?})", event);
 187         let task_queue_len = self.task_pool.handle.len();
 188         if task_queue_len > 0 {
 189             log::info!("task queue len: {}", task_queue_len);
 190         }
 191
 192         let was_quiescent = self.is_quiescent();
 193         match event {
 194             Event::Lsp(msg) => match msg {
 195                 lsp_server::Message::Request(req) => self.on_request(loop_start, req)?,
 196                 lsp_server::Message::Notification(not) => {
 197                     self.on_notification(not)?;
 198                 }
 199                 lsp_server::Message::Response(resp) => self.complete_request(resp),
 200             },
 201             Event::Task(mut task) => {
 202                 let _p = profile::span("GlobalState::handle_event/task");
 203                 let mut prime_caches_progress = Vec::new();
 204                 loop {
 205                     match task {
 206                         Task::Response(response) => self.respond(response),
 207                         Task::Diagnostics(diagnostics_per_file) => {
 208                             for (file_id, diagnostics) in diagnostics_per_file {
 209                                 self.diagnostics.set_native_diagnostics(file_id, diagnostics)
 210                             }
 211                         }
 212                         Task::PrimeCaches(progress) => match progress {
 213                             PrimeCachesProgress::Started => prime_caches_progress.push(progress),
 214                             PrimeCachesProgress::StartedOnCrate { .. } => {
 215                                 match prime_caches_progress.last_mut() {
 216                                     Some(last @ PrimeCachesProgress::StartedOnCrate { .. }) => {
 217                                         // Coalesce subsequent update events.
 218                                         *last = progress;
 219                                     }
 220                                     _ => prime_caches_progress.push(progress),
 221                                 }
 222                             }
 223                             PrimeCachesProgress::Finished => prime_caches_progress.push(progress),
 224                         },
 225                         Task::FetchWorkspace(progress) => {
 226                             let (state, msg) = match progress {
 227                                 ProjectWorkspaceProgress::Begin => (Progress::Begin, None),
 228                                 ProjectWorkspaceProgress::Report(msg) => {
 229                                     (Progress::Report, Some(msg))
 230                                 }
 231                                 ProjectWorkspaceProgress::End(workspaces) => {
 232                                     self.fetch_workspaces_completed(workspaces);
 233
 234                                     let old = Arc::clone(&self.workspaces);
 235                                     self.switch_workspaces();
 236                                     let workspaces_updated = !Arc::ptr_eq(&old, &self.workspaces);
 237
 238                                     if self.config.run_build_scripts() && workspaces_updated {
 239                                         let mut collector =
 240                                             BuildDataCollector::new(self.config.wrap_rustc());
 241                                         for ws in self.workspaces.iter() {
 242                                             ws.collect_build_data_configs(&mut collector);
 243                                         }
 244                                         self.fetch_build_data_request(collector)
 245                                     }
 246
 247                                     (Progress::End, None)
 248                                 }
 249                             };
 250
 251                             self.report_progress("Fetching", state, msg, None);
 252                         }
 253                         Task::FetchBuildData(progress) => {
 254                             let (state, msg) = match progress {
 255                                 BuildDataProgress::Begin => (Some(Progress::Begin), None),
 256                                 BuildDataProgress::Report(msg) => {
 257                                     (Some(Progress::Report), Some(msg))
 258                                 }
 259                                 BuildDataProgress::End(build_data_result) => {
 260                                     self.fetch_build_data_completed(build_data_result);
 261
 262                                     self.switch_workspaces();
 263
 264                                     (Some(Progress::End), None)
 265                                 }
 266                             };
 267
 268                             if let Some(state) = state {
 269                                 self.report_progress("Loading", state, msg, None);
 270                             }
 271                         }
 272                     }
 273
 274                     // Coalesce multiple task events into one loop turn
 275                     task = match self.task_pool.receiver.try_recv() {
 276                         Ok(task) => task,
 277                         Err(_) => break,
 278                     };
 279                 }
 280
 281                 for progress in prime_caches_progress {
 282                     let (state, message, fraction);
 283                     match progress {
 284                         PrimeCachesProgress::Started => {
 285                             state = Progress::Begin;
 286                             message = None;
 287                             fraction = 0.0;
 288                         }
 289                         PrimeCachesProgress::StartedOnCrate { on_crate, n_done, n_total } => {
 290                             state = Progress::Report;
 291                             message = Some(format!("{}/{} ({})", n_done, n_total, on_crate));
 292                             fraction = Progress::fraction(n_done, n_total);
 293                         }
 294                         PrimeCachesProgress::Finished => {
 295                             state = Progress::End;
 296                             message = None;
 297                             fraction = 1.0;
 298
 299                             self.prime_caches_queue.op_completed(());
 300                         }
 301                     };
 302
 303                     self.report_progress("Indexing", state, message, Some(fraction));
 304                 }
 305             }
 306             Event::Vfs(mut task) => {
 307                 let _p = profile::span("GlobalState::handle_event/vfs");
 308                 loop {
 309                     match task {
 310                         vfs::loader::Message::Loaded { files } => {
 311                             let vfs = &mut self.vfs.write().0;
 312                             for (path, contents) in files {
 313                                 let path = VfsPath::from(path);
 314                                 if !self.mem_docs.contains_key(&path) {
 315                                     vfs.set_file_contents(path, contents);
 316                                 }
 317                             }
 318                         }
 319                         vfs::loader::Message::Progress { n_total, n_done, config_version } => {
 320                             always!(config_version <= self.vfs_config_version);
 321
 322                             self.vfs_progress_config_version = config_version;
 323                             self.vfs_progress_n_total = n_total;
 324                             self.vfs_progress_n_done = n_done;
 325
 326                             let state = if n_done == 0 {
 327                                 Progress::Begin
 328                             } else if n_done < n_total {
 329                                 Progress::Report
 330                             } else {
 331                                 assert_eq!(n_done, n_total);
 332                                 Progress::End
 333                             };
 334                             self.report_progress(
 335                                 "Roots Scanned",
 336                                 state,
 337                                 Some(format!("{}/{}", n_done, n_total)),
 338                                 Some(Progress::fraction(n_done, n_total)),
 339                             )
 340                         }
 341                     }
 342                     // Coalesce many VFS event into a single loop turn
 343                     task = match self.loader.receiver.try_recv() {
 344                         Ok(task) => task,
 345                         Err(_) => break,
 346                     }
 347                 }
 348             }
 349             Event::Flycheck(mut task) => {
 350                 let _p = profile::span("GlobalState::handle_event/flycheck");
 351                 loop {
 352                     match task {
 353                         flycheck::Message::AddDiagnostic { workspace_root, diagnostic } => {
 354                             let diagnostics =
 355                                 crate::diagnostics::to_proto::map_rust_diagnostic_to_lsp(
 356                                     &self.config.diagnostics_map(),
 357                                     &diagnostic,
 358                                     &workspace_root,
 359                                 );
 360                             for diag in diagnostics {
 361                                 match url_to_file_id(&self.vfs.read().0, &diag.url) {
 362                                     Ok(file_id) => self.diagnostics.add_check_diagnostic(
 363                                         file_id,
 364                                         diag.diagnostic,
 365                                         diag.fixes,
 366                                     ),
 367                                     Err(err) => {
 368                                         log::error!(
 369                                             "File with cargo diagnostic not found in VFS: {}",
 370                                             err
 371                                         );
 372                                     }
 373                                 };
 374                             }
 375                         }
 376
 377                         flycheck::Message::Progress { id, progress } => {
 378                             let (state, message) = match progress {
 379                                 flycheck::Progress::DidStart => {
 380                                     self.diagnostics.clear_check();
 381                                     (Progress::Begin, None)
 382                                 }
 383                                 flycheck::Progress::DidCheckCrate(target) => {
 384                                     (Progress::Report, Some(target))
 385                                 }
 386                                 flycheck::Progress::DidCancel => (Progress::End, None),
 387                                 flycheck::Progress::DidFinish(result) => {
 388                                     if let Err(err) = result {
 389                                         log::error!("cargo check failed: {}", err)
 390                                     }
 391                                     (Progress::End, None)
 392                                 }
 393                             };
 394
 395                             // When we're running multiple flychecks, we have to include a disambiguator in
 396                             // the title, or the editor complains. Note that this is a user-facing string.
 397                             let title = if self.flycheck.len() == 1 {
 398                                 "cargo check".to_string()
 399                             } else {
 400                                 format!("cargo check (#{})", id + 1)
 401                             };
 402                             self.report_progress(&title, state, message, None);
 403                         }
 404                     }
 405                     // Coalesce many flycheck updates into a single loop turn
 406                     task = match self.flycheck_receiver.try_recv() {
 407                         Ok(task) => task,
 408                         Err(_) => break,
 409                     }
 410                 }
 411             }
 412         }
 413
 414         let state_changed = self.process_changes();
 415
 416         if self.is_quiescent() && !was_quiescent {
 417             for flycheck in &self.flycheck {
 418                 flycheck.update();
 419             }
 420         }
 421
 422         if self.is_quiescent() && (!was_quiescent || state_changed) {
 423             self.update_file_notifications_on_threadpool();
 424
 425             // Refresh semantic tokens if the client supports it.
 426             if self.config.semantic_tokens_refresh() {
 427                 self.semantic_tokens_cache.lock().clear();
 428                 self.send_request::<lsp_types::request::SemanticTokensRefesh>((), |_, _| ());
 429             }
 430
 431             // Refresh code lens if the client supports it.
 432             if self.config.code_lens_refresh() {
 433                 self.send_request::<lsp_types::request::CodeLensRefresh>((), |_, _| ());
 434             }
 435         }
 436
 437         if let Some(diagnostic_changes) = self.diagnostics.take_changes() {
 438             for file_id in diagnostic_changes {
 439                 let url = file_id_to_url(&self.vfs.read().0, file_id);
 440                 let diagnostics = self.diagnostics.diagnostics_for(file_id).cloned().collect();
 441                 let version = from_proto::vfs_path(&url)
 442                     .map(|path| self.mem_docs.get(&path).map(|it| it.version))
 443                     .unwrap_or_default();
 444
 445                 self.send_notification::<lsp_types::notification::PublishDiagnostics>(
 446                     lsp_types::PublishDiagnosticsParams { uri: url, diagnostics, version },
 447                 );
 448             }
 449         }
 450
 451         if self.config.cargo_autoreload() {
 452             self.fetch_workspaces_if_needed();
 453         }
 454         self.fetch_build_data_if_needed();
 455
 456         self.report_new_status_if_needed();
 457
 458         let loop_duration = loop_start.elapsed();
 459         if loop_duration > Duration::from_millis(100) {
 460             log::warn!("overly long loop turn: {:?}", loop_duration);
 461             if env::var("RA_PROFILE").is_ok() {
 462                 self.show_message(
 463                     lsp_types::MessageType::Error,
 464                     format!("overly long loop turn: {:?}", loop_duration),
 465                 )
 466             }
 467         }
 468         Ok(())
 469     }
 470
 471     fn on_request(&mut self, request_received: Instant, req: Request) -> Result<()> {
 472         self.register_request(&req, request_received);
 473
 474         if self.shutdown_requested {
 475             self.respond(Response::new_err(
 476                 req.id,
 477                 lsp_server::ErrorCode::InvalidRequest as i32,
 478                 "Shutdown already requested.".to_owned(),
 479             ));
 480
 481             return Ok(());
 482         }
 483
 484         // Avoid flashing a bunch of unresolved references during initial load.
 485         if self.workspaces.is_empty() && !self.is_quiescent() {
 486             self.respond(lsp_server::Response::new_err(
 487                 req.id,
 488                 // FIXME: i32 should impl From<ErrorCode> (from() guarantees lossless conversion)
 489                 lsp_server::ErrorCode::ContentModified as i32,
 490                 "waiting for cargo metadata or cargo check".to_owned(),
 491             ));
 492             return Ok(());
 493         }
 494
 495         RequestDispatcher { req: Some(req), global_state: self }
 496             .on_sync::<lsp_ext::ReloadWorkspace>(|s, ()| {
 497                 s.fetch_workspaces_request();
 498                 s.fetch_workspaces_if_needed();
 499                 Ok(())
 500             })?
 501             .on_sync::<lsp_ext::JoinLines>(|s, p| handlers::handle_join_lines(s.snapshot(), p))?
 502             .on_sync::<lsp_ext::OnEnter>(|s, p| handlers::handle_on_enter(s.snapshot(), p))?
 503             .on_sync::<lsp_types::request::Shutdown>(|s, ()| {
 504                 s.shutdown_requested = true;
 505                 Ok(())
 506             })?
 507             .on_sync::<lsp_types::request::SelectionRangeRequest>(|s, p| {
 508                 handlers::handle_selection_range(s.snapshot(), p)
 509             })?
 510             .on_sync::<lsp_ext::MatchingBrace>(|s, p| {
 511                 handlers::handle_matching_brace(s.snapshot(), p)
 512             })?
 513             .on_sync::<lsp_ext::MemoryUsage>(|s, p| handlers::handle_memory_usage(s, p))?
 514             .on::<lsp_ext::AnalyzerStatus>(handlers::handle_analyzer_status)
 515             .on::<lsp_ext::SyntaxTree>(handlers::handle_syntax_tree)
 516             .on::<lsp_ext::ViewHir>(handlers::handle_view_hir)
 517             .on::<lsp_ext::ViewCrateGraph>(handlers::handle_view_crate_graph)
 518             .on::<lsp_ext::ViewItemTree>(handlers::handle_view_item_tree)
 519             .on::<lsp_ext::ExpandMacro>(handlers::handle_expand_macro)
 520             .on::<lsp_ext::ParentModule>(handlers::handle_parent_module)
 521             .on::<lsp_ext::Runnables>(handlers::handle_runnables)
 522             .on::<lsp_ext::RelatedTests>(handlers::handle_related_tests)
 523             .on::<lsp_ext::InlayHints>(handlers::handle_inlay_hints)
 524             .on::<lsp_ext::CodeActionRequest>(handlers::handle_code_action)
 525             .on::<lsp_ext::CodeActionResolveRequest>(handlers::handle_code_action_resolve)
 526             .on::<lsp_ext::HoverRequest>(handlers::handle_hover)
 527             .on::<lsp_ext::ExternalDocs>(handlers::handle_open_docs)
 528             .on::<lsp_ext::OpenCargoToml>(handlers::handle_open_cargo_toml)
 529             .on::<lsp_ext::MoveItem>(handlers::handle_move_item)
 530             .on::<lsp_ext::WorkspaceSymbol>(handlers::handle_workspace_symbol)
 531             .on::<lsp_types::request::OnTypeFormatting>(handlers::handle_on_type_formatting)
 532             .on::<lsp_types::request::DocumentSymbolRequest>(handlers::handle_document_symbol)
 533             .on::<lsp_types::request::GotoDefinition>(handlers::handle_goto_definition)
 534             .on::<lsp_types::request::GotoImplementation>(handlers::handle_goto_implementation)
 535             .on::<lsp_types::request::GotoTypeDefinition>(handlers::handle_goto_type_definition)
 536             .on::<lsp_types::request::Completion>(handlers::handle_completion)
 537             .on::<lsp_types::request::ResolveCompletionItem>(handlers::handle_completion_resolve)
 538             .on::<lsp_types::request::CodeLensRequest>(handlers::handle_code_lens)
 539             .on::<lsp_types::request::CodeLensResolve>(handlers::handle_code_lens_resolve)
 540             .on::<lsp_types::request::FoldingRangeRequest>(handlers::handle_folding_range)
 541             .on::<lsp_types::request::SignatureHelpRequest>(handlers::handle_signature_help)
 542             .on::<lsp_types::request::PrepareRenameRequest>(handlers::handle_prepare_rename)
 543             .on::<lsp_types::request::Rename>(handlers::handle_rename)
 544             .on::<lsp_types::request::References>(handlers::handle_references)
 545             .on::<lsp_types::request::Formatting>(handlers::handle_formatting)
 546             .on::<lsp_types::request::RangeFormatting>(handlers::handle_range_formatting)
 547             .on::<lsp_types::request::DocumentHighlightRequest>(handlers::handle_document_highlight)
 548             .on::<lsp_types::request::CallHierarchyPrepare>(handlers::handle_call_hierarchy_prepare)
 549             .on::<lsp_types::request::CallHierarchyIncomingCalls>(
 550                 handlers::handle_call_hierarchy_incoming,
 551             )
 552             .on::<lsp_types::request::CallHierarchyOutgoingCalls>(
 553                 handlers::handle_call_hierarchy_outgoing,
 554             )
 555             .on::<lsp_types::request::SemanticTokensFullRequest>(
 556                 handlers::handle_semantic_tokens_full,
 557             )
 558             .on::<lsp_types::request::SemanticTokensFullDeltaRequest>(
 559                 handlers::handle_semantic_tokens_full_delta,
 560             )
 561             .on::<lsp_types::request::SemanticTokensRangeRequest>(
 562                 handlers::handle_semantic_tokens_range,
 563             )
 564             .on::<lsp_types::request::WillRenameFiles>(handlers::handle_will_rename_files)
 565             .on::<lsp_ext::Ssr>(handlers::handle_ssr)
 566             .finish();
 567         Ok(())
 568     }
 569     fn on_notification(&mut self, not: Notification) -> Result<()> {
 570         NotificationDispatcher { not: Some(not), global_state: self }
 571             .on::<lsp_types::notification::Cancel>(|this, params| {
 572                 let id: lsp_server::RequestId = match params.id {
 573                     lsp_types::NumberOrString::Number(id) => id.into(),
 574                     lsp_types::NumberOrString::String(id) => id.into(),
 575                 };
 576                 this.cancel(id);
 577                 Ok(())
 578             })?
 579             .on::<lsp_types::notification::WorkDoneProgressCancel>(|_this, _params| {
 580                 // Just ignore this. It is OK to continue sending progress
 581                 // notifications for this token, as the client can't know when
 582                 // we accepted notification.
 583                 Ok(())
 584             })?
 585             .on::<lsp_types::notification::DidOpenTextDocument>(|this, params| {
 586                 if let Ok(path) = from_proto::vfs_path(&params.text_document.uri) {
 587                     if this
 588                         .mem_docs
 589                         .insert(path.clone(), DocumentData::new(params.text_document.version))
 590                         .is_some()
 591                     {
 592                         log::error!("duplicate DidOpenTextDocument: {}", path)
 593                     }
 594                     let changed = this
 595                         .vfs
 596                         .write()
 597                         .0
 598                         .set_file_contents(path, Some(params.text_document.text.into_bytes()));
 599
 600                     // If the VFS contents are unchanged, update diagnostics, since `handle_event`
 601                     // won't see any changes. This avoids missing diagnostics when opening a file.
 602                     //
 603                     // If the file *was* changed, `handle_event` will already recompute and send
 604                     // diagnostics. We can't do it here, since the *current* file contents might be
 605                     // unset in salsa, since the VFS change hasn't been applied to the database yet.
 606                     if !changed {
 607                         this.maybe_update_diagnostics();
 608                     }
 609                 }
 610                 Ok(())
 611             })?
 612             .on::<lsp_types::notification::DidChangeTextDocument>(|this, params| {
 613                 if let Ok(path) = from_proto::vfs_path(&params.text_document.uri) {
 614                     let doc = match this.mem_docs.get_mut(&path) {
 615                         Some(doc) => doc,
 616                         None => {
 617                             log::error!("expected DidChangeTextDocument: {}", path);
 618                             return Ok(());
 619                         }
 620                     };
 621                     let vfs = &mut this.vfs.write().0;
 622                     let file_id = vfs.file_id(&path).unwrap();
 623                     let mut text = String::from_utf8(vfs.file_contents(file_id).to_vec()).unwrap();
 624                     apply_document_changes(&mut text, params.content_changes);
 625
 626                     // The version passed in DidChangeTextDocument is the version after all edits are applied
 627                     // so we should apply it before the vfs is notified.
 628                     doc.version = params.text_document.version;
 629
 630                     vfs.set_file_contents(path.clone(), Some(text.into_bytes()));
 631                 }
 632                 Ok(())
 633             })?
 634             .on::<lsp_types::notification::DidCloseTextDocument>(|this, params| {
 635                 let mut version = None;
 636                 if let Ok(path) = from_proto::vfs_path(&params.text_document.uri) {
 637                     match this.mem_docs.remove(&path) {
 638                         Some(doc) => version = Some(doc.version),
 639                         None => log::error!("orphan DidCloseTextDocument: {}", path),
 640                     }
 641
 642                     this.semantic_tokens_cache.lock().remove(&params.text_document.uri);
 643
 644                     if let Some(path) = path.as_path() {
 645                         this.loader.handle.invalidate(path.to_path_buf());
 646                     }
 647                 }
 648
 649                 // Clear the diagnostics for the previously known version of the file.
 650                 // This prevents stale "cargo check" diagnostics if the file is
 651                 // closed, "cargo check" is run and then the file is reopened.
 652                 this.send_notification::<lsp_types::notification::PublishDiagnostics>(
 653                     lsp_types::PublishDiagnosticsParams {
 654                         uri: params.text_document.uri,
 655                         diagnostics: Vec::new(),
 656                         version,
 657                     },
 658                 );
 659                 Ok(())
 660             })?
 661             .on::<lsp_types::notification::DidSaveTextDocument>(|this, params| {
 662                 for flycheck in &this.flycheck {
 663                     flycheck.update();
 664                 }
 665                 if let Ok(abs_path) = from_proto::abs_path(&params.text_document.uri) {
 666                     this.maybe_refresh(&[(abs_path, ChangeKind::Modify)]);
 667                 }
 668                 Ok(())
 669             })?
 670             .on::<lsp_types::notification::DidChangeConfiguration>(|this, _params| {
 671                 // As stated in https://github.com/microsoft/language-server-protocol/issues/676,
 672                 // this notification's parameters should be ignored and the actual config queried separately.
 673                 this.send_request::<lsp_types::request::WorkspaceConfiguration>(
 674                     lsp_types::ConfigurationParams {
 675                         items: vec![lsp_types::ConfigurationItem {
 676                             scope_uri: None,
 677                             section: Some("rust-analyzer".to_string()),
 678                         }],
 679                     },
 680                     |this, resp| {
 681                         log::debug!("config update response: '{:?}", resp);
 682                         let Response { error, result, .. } = resp;
 683
 684                         match (error, result) {
 685                             (Some(err), _) => {
 686                                 log::error!("failed to fetch the server settings: {:?}", err)
 687                             }
 688                             (None, Some(mut configs)) => {
 689                                 if let Some(json) = configs.get_mut(0) {
 690                                     // Note that json can be null according to the spec if the client can't
 691                                     // provide a configuration. This is handled in Config::update below.
 692                                     let mut config = Config::clone(&*this.config);
 693                                     config.update(json.take());
 694                                     this.update_configuration(config);
 695                                 }
 696                             }
 697                             (None, None) => log::error!(
 698                                 "received empty server settings response from the client"
 699                             ),
 700                         }
 701                     },
 702                 );
 703
 704                 Ok(())
 705             })?
 706             .on::<lsp_types::notification::DidChangeWatchedFiles>(|this, params| {
 707                 for change in params.changes {
 708                     if let Ok(path) = from_proto::abs_path(&change.uri) {
 709                         this.loader.handle.invalidate(path);
 710                     }
 711                 }
 712                 Ok(())
 713             })?
 714             .finish();
 715         Ok(())
 716     }
 717     fn update_file_notifications_on_threadpool(&mut self) {
 718         self.maybe_update_diagnostics();
 719
 720         // Ensure that only one cache priming task can run at a time
 721         self.prime_caches_queue.request_op(());
 722         if self.prime_caches_queue.should_start_op().is_none() {
 723             return;
 724         }
 725
 726         self.task_pool.handle.spawn_with_sender({
 727             let snap = self.snapshot();
 728             move |sender| {
 729                 let cb = |progress| {
 730                     sender.send(Task::PrimeCaches(progress)).unwrap();
 731                 };
 732                 match snap.analysis.prime_caches(cb) {
 733                     Ok(()) => (),
 734                     Err(_canceled) => (),
 735                 }
 736             }
 737         });
 738     }
 739     fn maybe_update_diagnostics(&mut self) {
 740         let subscriptions = self
 741             .mem_docs
 742             .keys()
 743             .map(|path| self.vfs.read().0.file_id(path).unwrap())
 744             .collect::<Vec<_>>();
 745
 746         log::trace!("updating notifications for {:?}", subscriptions);
 747         if self.config.publish_diagnostics() {
 748             let snapshot = self.snapshot();
 749             self.task_pool.handle.spawn(move || {
 750                 let diagnostics = subscriptions
 751                     .into_iter()
 752                     .filter_map(|file_id| {
 753                         handlers::publish_diagnostics(&snapshot, file_id)
 754                             .map_err(|err| {
 755                                 if !is_cancelled(&*err) {
 756                                     log::error!("failed to compute diagnostics: {:?}", err);
 757                                 }
 758                                 ()
 759                             })
 760                             .ok()
 761                             .map(|diags| (file_id, diags))
 762                     })
 763                     .collect::<Vec<_>>();
 764                 Task::Diagnostics(diagnostics)
 765             })
 766         }
 767     }
 768 }