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