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