clang-tools-extra/clangd/ClangdServer.cpp

   1 //===--- ClangdServer.cpp - Main clangd server code --------------*- C++-*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===-------------------------------------------------------------------===//
   8
   9 #include "ClangdServer.h"
  10 #include "CodeComplete.h"
  11 #include "Config.h"
  12 #include "Diagnostics.h"
  13 #include "DumpAST.h"
  14 #include "FindSymbols.h"
  15 #include "Format.h"
  16 #include "HeaderSourceSwitch.h"
  17 #include "InlayHints.h"
  18 #include "ParsedAST.h"
  19 #include "Preamble.h"
  20 #include "Protocol.h"
  21 #include "SemanticHighlighting.h"
  22 #include "SemanticSelection.h"
  23 #include "SourceCode.h"
  24 #include "TUScheduler.h"
  25 #include "XRefs.h"
  26 #include "clang-include-cleaner/Record.h"
  27 #include "index/FileIndex.h"
  28 #include "index/Merge.h"
  29 #include "index/StdLib.h"
  30 #include "refactor/Rename.h"
  31 #include "refactor/Tweak.h"
  32 #include "support/Cancellation.h"
  33 #include "support/Context.h"
  34 #include "support/Logger.h"
  35 #include "support/MemoryTree.h"
  36 #include "support/ThreadsafeFS.h"
  37 #include "support/Trace.h"
  38 #include "clang/Basic/Stack.h"
  39 #include "clang/Format/Format.h"
  40 #include "clang/Lex/Preprocessor.h"
  41 #include "clang/Tooling/CompilationDatabase.h"
  42 #include "clang/Tooling/Core/Replacement.h"
  43 #include "llvm/ADT/ArrayRef.h"
  44 #include "llvm/ADT/STLExtras.h"
  45 #include "llvm/ADT/StringRef.h"
  46 #include "llvm/Support/Error.h"
  47 #include "llvm/Support/Path.h"
  48 #include "llvm/Support/raw_ostream.h"
  49 #include <algorithm>
  50 #include <chrono>
  51 #include <future>
  52 #include <memory>
  53 #include <mutex>
  54 #include <optional>
  55 #include <string>
  56 #include <type_traits>
  57 #include <utility>
  58 #include <vector>
  59
  60 namespace clang {
  61 namespace clangd {
  62 namespace {
  63
  64 // Tracks number of times a tweak has been offered.
  65 static constexpr trace::Metric TweakAvailable(
  66     "tweak_available", trace::Metric::Counter, "tweak_id");
  67
  68 // Update the FileIndex with new ASTs and plumb the diagnostics responses.
  69 struct UpdateIndexCallbacks : public ParsingCallbacks {
  70   UpdateIndexCallbacks(FileIndex *FIndex,
  71                        ClangdServer::Callbacks *ServerCallbacks,
  72                        const ThreadsafeFS &TFS, AsyncTaskRunner *Tasks,
  73                        bool CollectInactiveRegions)
  74       : FIndex(FIndex), ServerCallbacks(ServerCallbacks), TFS(TFS),
  75         Stdlib{std::make_shared<StdLibSet>()}, Tasks(Tasks),
  76         CollectInactiveRegions(CollectInactiveRegions) {}
  77
  78   void onPreambleAST(
  79       PathRef Path, llvm::StringRef Version, CapturedASTCtx ASTCtx,
  80       std::shared_ptr<const include_cleaner::PragmaIncludes> PI) override {
  81
  82     if (!FIndex)
  83       return;
  84
  85     auto &PP = ASTCtx.getPreprocessor();
  86     auto &CI = ASTCtx.getCompilerInvocation();
  87     if (auto Loc = Stdlib->add(CI.getLangOpts(), PP.getHeaderSearchInfo()))
  88       indexStdlib(CI, std::move(*Loc));
  89
  90     // FIndex outlives the UpdateIndexCallbacks.
  91     auto Task = [FIndex(FIndex), Path(Path.str()), Version(Version.str()),
  92                  ASTCtx(std::move(ASTCtx)), PI(std::move(PI))]() mutable {
  93       trace::Span Tracer("PreambleIndexing");
  94       FIndex->updatePreamble(Path, Version, ASTCtx.getASTContext(),
  95                              ASTCtx.getPreprocessor(), *PI);
  96     };
  97
  98     if (Tasks) {
  99       Tasks->runAsync("Preamble indexing for:" + Path + Version,
 100                       std::move(Task));
 101     } else
 102       Task();
 103   }
 104
 105   void indexStdlib(const CompilerInvocation &CI, StdLibLocation Loc) {
 106     // This task is owned by Tasks, which outlives the TUScheduler and
 107     // therefore the UpdateIndexCallbacks.
 108     // We must be careful that the references we capture outlive TUScheduler.
 109     auto Task = [LO(CI.getLangOpts()), Loc(std::move(Loc)),
 110                  CI(std::make_unique<CompilerInvocation>(CI)),
 111                  // External values that outlive ClangdServer
 112                  TFS(&TFS),
 113                  // Index outlives TUScheduler (declared first)
 114                  FIndex(FIndex),
 115                  // shared_ptr extends lifetime
 116                  Stdlib(Stdlib),
 117                  // We have some FS implementations that rely on information in
 118                  // the context.
 119                  Ctx(Context::current().clone())]() mutable {
 120       // Make sure we install the context into current thread.
 121       WithContext C(std::move(Ctx));
 122       clang::noteBottomOfStack();
 123       IndexFileIn IF;
 124       IF.Symbols = indexStandardLibrary(std::move(CI), Loc, *TFS);
 125       if (Stdlib->isBest(LO))
 126         FIndex->updatePreamble(std::move(IF));
 127     };
 128     if (Tasks)
 129       // This doesn't have a semaphore to enforce -j, but it's rare.
 130       Tasks->runAsync("IndexStdlib", std::move(Task));
 131     else
 132       Task();
 133   }
 134
 135   void onMainAST(PathRef Path, ParsedAST &AST, PublishFn Publish) override {
 136     if (FIndex)
 137       FIndex->updateMain(Path, AST);
 138
 139     if (ServerCallbacks)
 140       Publish([&]() {
 141         ServerCallbacks->onDiagnosticsReady(Path, AST.version(),
 142                                             AST.getDiagnostics());
 143         if (CollectInactiveRegions) {
 144           ServerCallbacks->onInactiveRegionsReady(Path,
 145                                                   getInactiveRegions(AST));
 146         }
 147       });
 148   }
 149
 150   void onFailedAST(PathRef Path, llvm::StringRef Version,
 151                    std::vector<Diag> Diags, PublishFn Publish) override {
 152     if (ServerCallbacks)
 153       Publish(
 154           [&]() { ServerCallbacks->onDiagnosticsReady(Path, Version, Diags); });
 155   }
 156
 157   void onFileUpdated(PathRef File, const TUStatus &Status) override {
 158     if (ServerCallbacks)
 159       ServerCallbacks->onFileUpdated(File, Status);
 160   }
 161
 162   void onPreamblePublished(PathRef File) override {
 163     if (ServerCallbacks)
 164       ServerCallbacks->onSemanticsMaybeChanged(File);
 165   }
 166
 167 private:
 168   FileIndex *FIndex;
 169   ClangdServer::Callbacks *ServerCallbacks;
 170   const ThreadsafeFS &TFS;
 171   std::shared_ptr<StdLibSet> Stdlib;
 172   AsyncTaskRunner *Tasks;
 173   bool CollectInactiveRegions;
 174 };
 175
 176 class DraftStoreFS : public ThreadsafeFS {
 177 public:
 178   DraftStoreFS(const ThreadsafeFS &Base, const DraftStore &Drafts)
 179       : Base(Base), DirtyFiles(Drafts) {}
 180
 181 private:
 182   llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> viewImpl() const override {
 183     auto OFS = llvm::makeIntrusiveRefCnt<llvm::vfs::OverlayFileSystem>(
 184         Base.view(std::nullopt));
 185     OFS->pushOverlay(DirtyFiles.asVFS());
 186     return OFS;
 187   }
 188
 189   const ThreadsafeFS &Base;
 190   const DraftStore &DirtyFiles;
 191 };
 192
 193 } // namespace
 194
 195 ClangdServer::Options ClangdServer::optsForTest() {
 196   ClangdServer::Options Opts;
 197   Opts.UpdateDebounce = DebouncePolicy::fixed(/*zero*/ {});
 198   Opts.StorePreamblesInMemory = true;
 199   Opts.AsyncThreadsCount = 4; // Consistent!
 200   return Opts;
 201 }
 202
 203 ClangdServer::Options::operator TUScheduler::Options() const {
 204   TUScheduler::Options Opts;
 205   Opts.AsyncThreadsCount = AsyncThreadsCount;
 206   Opts.RetentionPolicy = RetentionPolicy;
 207   Opts.StorePreamblesInMemory = StorePreamblesInMemory;
 208   Opts.UpdateDebounce = UpdateDebounce;
 209   Opts.ContextProvider = ContextProvider;
 210   Opts.PreambleThrottler = PreambleThrottler;
 211   return Opts;
 212 }
 213
 214 ClangdServer::ClangdServer(const GlobalCompilationDatabase &CDB,
 215                            const ThreadsafeFS &TFS, const Options &Opts,
 216                            Callbacks *Callbacks)
 217     : FeatureModules(Opts.FeatureModules), CDB(CDB), TFS(TFS),
 218       DynamicIdx(Opts.BuildDynamicSymbolIndex ? new FileIndex() : nullptr),
 219       ModulesManager(Opts.ModulesManager),
 220       ClangTidyProvider(Opts.ClangTidyProvider),
 221       UseDirtyHeaders(Opts.UseDirtyHeaders),
 222       LineFoldingOnly(Opts.LineFoldingOnly),
 223       PreambleParseForwardingFunctions(Opts.PreambleParseForwardingFunctions),
 224       ImportInsertions(Opts.ImportInsertions),
 225       PublishInactiveRegions(Opts.PublishInactiveRegions),
 226       WorkspaceRoot(Opts.WorkspaceRoot),
 227       Transient(Opts.ImplicitCancellation ? TUScheduler::InvalidateOnUpdate
 228                                           : TUScheduler::NoInvalidation),
 229       DirtyFS(std::make_unique<DraftStoreFS>(TFS, DraftMgr)) {
 230   if (Opts.AsyncThreadsCount != 0)
 231     IndexTasks.emplace();
 232   // Pass a callback into `WorkScheduler` to extract symbols from a newly
 233   // parsed file and rebuild the file index synchronously each time an AST
 234   // is parsed.
 235   WorkScheduler.emplace(CDB, TUScheduler::Options(Opts),
 236                         std::make_unique<UpdateIndexCallbacks>(
 237                             DynamicIdx.get(), Callbacks, TFS,
 238                             IndexTasks ? &*IndexTasks : nullptr,
 239                             PublishInactiveRegions));
 240   // Adds an index to the stack, at higher priority than existing indexes.
 241   auto AddIndex = [&](SymbolIndex *Idx) {
 242     if (this->Index != nullptr) {
 243       MergedIdx.push_back(std::make_unique<MergedIndex>(Idx, this->Index));
 244       this->Index = MergedIdx.back().get();
 245     } else {
 246       this->Index = Idx;
 247     }
 248   };
 249   if (Opts.StaticIndex)
 250     AddIndex(Opts.StaticIndex);
 251   if (Opts.BackgroundIndex) {
 252     BackgroundIndex::Options BGOpts;
 253     BGOpts.ThreadPoolSize = std::max(Opts.AsyncThreadsCount, 1u);
 254     BGOpts.OnProgress = [Callbacks](BackgroundQueue::Stats S) {
 255       if (Callbacks)
 256         Callbacks->onBackgroundIndexProgress(S);
 257     };
 258     BGOpts.ContextProvider = Opts.ContextProvider;
 259     BackgroundIdx = std::make_unique<BackgroundIndex>(
 260         TFS, CDB,
 261         BackgroundIndexStorage::createDiskBackedStorageFactory(
 262             [&CDB](llvm::StringRef File) { return CDB.getProjectInfo(File); }),
 263         std::move(BGOpts));
 264     AddIndex(BackgroundIdx.get());
 265   }
 266   if (DynamicIdx)
 267     AddIndex(DynamicIdx.get());
 268
 269   if (Opts.FeatureModules) {
 270     FeatureModule::Facilities F{
 271         *this->WorkScheduler,
 272         this->Index,
 273         this->TFS,
 274     };
 275     for (auto &Mod : *Opts.FeatureModules)
 276       Mod.initialize(F);
 277   }
 278 }
 279
 280 ClangdServer::~ClangdServer() {
 281   // Destroying TUScheduler first shuts down request threads that might
 282   // otherwise access members concurrently.
 283   // (Nobody can be using TUScheduler because we're on the main thread).
 284   WorkScheduler.reset();
 285   // Now requests have stopped, we can shut down feature modules.
 286   if (FeatureModules) {
 287     for (auto &Mod : *FeatureModules)
 288       Mod.stop();
 289     for (auto &Mod : *FeatureModules)
 290       Mod.blockUntilIdle(Deadline::infinity());
 291   }
 292 }
 293
 294 void ClangdServer::addDocument(PathRef File, llvm::StringRef Contents,
 295                                llvm::StringRef Version,
 296                                WantDiagnostics WantDiags, bool ForceRebuild) {
 297   std::string ActualVersion = DraftMgr.addDraft(File, Version, Contents);
 298   ParseOptions Opts;
 299   Opts.PreambleParseForwardingFunctions = PreambleParseForwardingFunctions;
 300   Opts.ImportInsertions = ImportInsertions;
 301
 302   // Compile command is set asynchronously during update, as it can be slow.
 303   ParseInputs Inputs;
 304   Inputs.TFS = &getHeaderFS();
 305   Inputs.Contents = std::string(Contents);
 306   Inputs.Version = std::move(ActualVersion);
 307   Inputs.ForceRebuild = ForceRebuild;
 308   Inputs.Opts = std::move(Opts);
 309   Inputs.Index = Index;
 310   Inputs.ClangTidyProvider = ClangTidyProvider;
 311   Inputs.FeatureModules = FeatureModules;
 312   Inputs.ModulesManager = ModulesManager;
 313   bool NewFile = WorkScheduler->update(File, Inputs, WantDiags);
 314   // If we loaded Foo.h, we want to make sure Foo.cpp is indexed.
 315   if (NewFile && BackgroundIdx)
 316     BackgroundIdx->boostRelated(File);
 317 }
 318
 319 void ClangdServer::reparseOpenFilesIfNeeded(
 320     llvm::function_ref<bool(llvm::StringRef File)> Filter) {
 321   // Reparse only opened files that were modified.
 322   for (const Path &FilePath : DraftMgr.getActiveFiles())
 323     if (Filter(FilePath))
 324       if (auto Draft = DraftMgr.getDraft(FilePath)) // else disappeared in race?
 325         addDocument(FilePath, *Draft->Contents, Draft->Version,
 326                     WantDiagnostics::Auto);
 327 }
 328
 329 std::shared_ptr<const std::string> ClangdServer::getDraft(PathRef File) const {
 330   auto Draft = DraftMgr.getDraft(File);
 331   if (!Draft)
 332     return nullptr;
 333   return std::move(Draft->Contents);
 334 }
 335
 336 std::function<Context(PathRef)>
 337 ClangdServer::createConfiguredContextProvider(const config::Provider *Provider,
 338                                               Callbacks *Publish) {
 339   if (!Provider)
 340     return [](llvm::StringRef) { return Context::current().clone(); };
 341
 342   struct Impl {
 343     const config::Provider *Provider;
 344     ClangdServer::Callbacks *Publish;
 345     std::mutex PublishMu;
 346
 347     Impl(const config::Provider *Provider, ClangdServer::Callbacks *Publish)
 348         : Provider(Provider), Publish(Publish) {}
 349
 350     Context operator()(llvm::StringRef File) {
 351       config::Params Params;
 352       // Don't reread config files excessively often.
 353       // FIXME: when we see a config file change event, use the event timestamp?
 354       Params.FreshTime =
 355           std::chrono::steady_clock::now() - std::chrono::seconds(5);
 356       llvm::SmallString<256> PosixPath;
 357       if (!File.empty()) {
 358         assert(llvm::sys::path::is_absolute(File));
 359         llvm::sys::path::native(File, PosixPath, llvm::sys::path::Style::posix);
 360         Params.Path = PosixPath.str();
 361       }
 362
 363       llvm::StringMap<std::vector<Diag>> ReportableDiagnostics;
 364       Config C = Provider->getConfig(Params, [&](const llvm::SMDiagnostic &D) {
 365         // Create the map entry even for note diagnostics we don't report.
 366         // This means that when the file is parsed with no warnings, we
 367         // publish an empty set of diagnostics, clearing any the client has.
 368         handleDiagnostic(D, !Publish || D.getFilename().empty()
 369                                 ? nullptr
 370                                 : &ReportableDiagnostics[D.getFilename()]);
 371       });
 372       // Blindly publish diagnostics for the (unopened) parsed config files.
 373       // We must avoid reporting diagnostics for *the same file* concurrently.
 374       // Source diags are published elsewhere, but those are different files.
 375       if (!ReportableDiagnostics.empty()) {
 376         std::lock_guard<std::mutex> Lock(PublishMu);
 377         for (auto &Entry : ReportableDiagnostics)
 378           Publish->onDiagnosticsReady(Entry.first(), /*Version=*/"",
 379                                       Entry.second);
 380       }
 381       return Context::current().derive(Config::Key, std::move(C));
 382     }
 383
 384     void handleDiagnostic(const llvm::SMDiagnostic &D,
 385                           std::vector<Diag> *ClientDiagnostics) {
 386       switch (D.getKind()) {
 387       case llvm::SourceMgr::DK_Error:
 388         elog("config error at {0}:{1}:{2}: {3}", D.getFilename(), D.getLineNo(),
 389              D.getColumnNo(), D.getMessage());
 390         break;
 391       case llvm::SourceMgr::DK_Warning:
 392         log("config warning at {0}:{1}:{2}: {3}", D.getFilename(),
 393             D.getLineNo(), D.getColumnNo(), D.getMessage());
 394         break;
 395       case llvm::SourceMgr::DK_Note:
 396       case llvm::SourceMgr::DK_Remark:
 397         vlog("config note at {0}:{1}:{2}: {3}", D.getFilename(), D.getLineNo(),
 398              D.getColumnNo(), D.getMessage());
 399         ClientDiagnostics = nullptr; // Don't emit notes as LSP diagnostics.
 400         break;
 401       }
 402       if (ClientDiagnostics)
 403         ClientDiagnostics->push_back(toDiag(D, Diag::ClangdConfig));
 404     }
 405   };
 406
 407   // Copyable wrapper.
 408   return [I(std::make_shared<Impl>(Provider, Publish))](llvm::StringRef Path) {
 409     return (*I)(Path);
 410   };
 411 }
 412
 413 void ClangdServer::removeDocument(PathRef File) {
 414   DraftMgr.removeDraft(File);
 415   WorkScheduler->remove(File);
 416 }
 417
 418 void ClangdServer::codeComplete(PathRef File, Position Pos,
 419                                 const clangd::CodeCompleteOptions &Opts,
 420                                 Callback<CodeCompleteResult> CB) {
 421   // Copy completion options for passing them to async task handler.
 422   auto CodeCompleteOpts = Opts;
 423   if (!CodeCompleteOpts.Index) // Respect overridden index.
 424     CodeCompleteOpts.Index = Index;
 425
 426   auto Task = [Pos, CodeCompleteOpts, File = File.str(), CB = std::move(CB),
 427                this](llvm::Expected<InputsAndPreamble> IP) mutable {
 428     if (!IP)
 429       return CB(IP.takeError());
 430     if (auto Reason = isCancelled())
 431       return CB(llvm::make_error<CancelledError>(Reason));
 432
 433     std::optional<SpeculativeFuzzyFind> SpecFuzzyFind;
 434     if (!IP->Preamble) {
 435       // No speculation in Fallback mode, as it's supposed to be much faster
 436       // without compiling.
 437       vlog("Build for file {0} is not ready. Enter fallback mode.", File);
 438     } else if (CodeCompleteOpts.Index) {
 439       SpecFuzzyFind.emplace();
 440       {
 441         std::lock_guard<std::mutex> Lock(CachedCompletionFuzzyFindRequestMutex);
 442         SpecFuzzyFind->CachedReq = CachedCompletionFuzzyFindRequestByFile[File];
 443       }
 444     }
 445     ParseInputs ParseInput{IP->Command, &getHeaderFS(), IP->Contents.str()};
 446     // FIXME: Add traling new line if there is none at eof, workaround a crash,
 447     // see https://github.com/clangd/clangd/issues/332
 448     if (!IP->Contents.ends_with("\n"))
 449       ParseInput.Contents.append("\n");
 450     ParseInput.Index = Index;
 451
 452     CodeCompleteOpts.MainFileSignals = IP->Signals;
 453     CodeCompleteOpts.AllScopes = Config::current().Completion.AllScopes;
 454     CodeCompleteOpts.ArgumentLists = Config::current().Completion.ArgumentLists;
 455     // FIXME(ibiryukov): even if Preamble is non-null, we may want to check
 456     // both the old and the new version in case only one of them matches.
 457     CodeCompleteResult Result = clangd::codeComplete(
 458         File, Pos, IP->Preamble, ParseInput, CodeCompleteOpts,
 459         SpecFuzzyFind ? &*SpecFuzzyFind : nullptr);
 460     {
 461       clang::clangd::trace::Span Tracer("Completion results callback");
 462       CB(std::move(Result));
 463     }
 464     if (SpecFuzzyFind && SpecFuzzyFind->NewReq) {
 465       std::lock_guard<std::mutex> Lock(CachedCompletionFuzzyFindRequestMutex);
 466       CachedCompletionFuzzyFindRequestByFile[File] = *SpecFuzzyFind->NewReq;
 467     }
 468     // SpecFuzzyFind is only destroyed after speculative fuzzy find finishes.
 469     // We don't want `codeComplete` to wait for the async call if it doesn't use
 470     // the result (e.g. non-index completion, speculation fails), so that `CB`
 471     // is called as soon as results are available.
 472   };
 473
 474   // We use a potentially-stale preamble because latency is critical here.
 475   WorkScheduler->runWithPreamble(
 476       "CodeComplete", File,
 477       (Opts.RunParser == CodeCompleteOptions::AlwaysParse)
 478           ? TUScheduler::Stale
 479           : TUScheduler::StaleOrAbsent,
 480       std::move(Task));
 481 }
 482
 483 void ClangdServer::signatureHelp(PathRef File, Position Pos,
 484                                  MarkupKind DocumentationFormat,
 485                                  Callback<SignatureHelp> CB) {
 486
 487   auto Action = [Pos, File = File.str(), CB = std::move(CB),
 488                  DocumentationFormat,
 489                  this](llvm::Expected<InputsAndPreamble> IP) mutable {
 490     if (!IP)
 491       return CB(IP.takeError());
 492
 493     const auto *PreambleData = IP->Preamble;
 494     if (!PreambleData)
 495       return CB(error("Failed to parse includes"));
 496
 497     ParseInputs ParseInput{IP->Command, &getHeaderFS(), IP->Contents.str()};
 498     // FIXME: Add traling new line if there is none at eof, workaround a crash,
 499     // see https://github.com/clangd/clangd/issues/332
 500     if (!IP->Contents.ends_with("\n"))
 501       ParseInput.Contents.append("\n");
 502     ParseInput.Index = Index;
 503     CB(clangd::signatureHelp(File, Pos, *PreambleData, ParseInput,
 504                              DocumentationFormat));
 505   };
 506
 507   // Unlike code completion, we wait for a preamble here.
 508   WorkScheduler->runWithPreamble("SignatureHelp", File, TUScheduler::Stale,
 509                                  std::move(Action));
 510 }
 511
 512 void ClangdServer::formatFile(PathRef File, std::optional<Range> Rng,
 513                               Callback<tooling::Replacements> CB) {
 514   auto Code = getDraft(File);
 515   if (!Code)
 516     return CB(llvm::make_error<LSPError>("trying to format non-added document",
 517                                          ErrorCode::InvalidParams));
 518   tooling::Range RequestedRange;
 519   if (Rng) {
 520     llvm::Expected<size_t> Begin = positionToOffset(*Code, Rng->start);
 521     if (!Begin)
 522       return CB(Begin.takeError());
 523     llvm::Expected<size_t> End = positionToOffset(*Code, Rng->end);
 524     if (!End)
 525       return CB(End.takeError());
 526     RequestedRange = tooling::Range(*Begin, *End - *Begin);
 527   } else {
 528     RequestedRange = tooling::Range(0, Code->size());
 529   }
 530
 531   // Call clang-format.
 532   auto Action = [File = File.str(), Code = std::move(*Code),
 533                  Ranges = std::vector<tooling::Range>{RequestedRange},
 534                  CB = std::move(CB), this]() mutable {
 535     format::FormatStyle Style = getFormatStyleForFile(File, Code, TFS, true);
 536     tooling::Replacements IncludeReplaces =
 537         format::sortIncludes(Style, Code, Ranges, File);
 538     auto Changed = tooling::applyAllReplacements(Code, IncludeReplaces);
 539     if (!Changed)
 540       return CB(Changed.takeError());
 541
 542     CB(IncludeReplaces.merge(format::reformat(
 543         Style, *Changed,
 544         tooling::calculateRangesAfterReplacements(IncludeReplaces, Ranges),
 545         File)));
 546   };
 547   WorkScheduler->runQuick("Format", File, std::move(Action));
 548 }
 549
 550 void ClangdServer::formatOnType(PathRef File, Position Pos,
 551                                 StringRef TriggerText,
 552                                 Callback<std::vector<TextEdit>> CB) {
 553   auto Code = getDraft(File);
 554   if (!Code)
 555     return CB(llvm::make_error<LSPError>("trying to format non-added document",
 556                                          ErrorCode::InvalidParams));
 557   llvm::Expected<size_t> CursorPos = positionToOffset(*Code, Pos);
 558   if (!CursorPos)
 559     return CB(CursorPos.takeError());
 560   auto Action = [File = File.str(), Code = std::move(*Code),
 561                  TriggerText = TriggerText.str(), CursorPos = *CursorPos,
 562                  CB = std::move(CB), this]() mutable {
 563     auto Style = getFormatStyleForFile(File, Code, TFS, false);
 564     std::vector<TextEdit> Result;
 565     for (const tooling::Replacement &R :
 566          formatIncremental(Code, CursorPos, TriggerText, Style))
 567       Result.push_back(replacementToEdit(Code, R));
 568     return CB(Result);
 569   };
 570   WorkScheduler->runQuick("FormatOnType", File, std::move(Action));
 571 }
 572
 573 void ClangdServer::prepareRename(PathRef File, Position Pos,
 574                                  std::optional<std::string> NewName,
 575                                  const RenameOptions &RenameOpts,
 576                                  Callback<RenameResult> CB) {
 577   auto Action = [Pos, File = File.str(), CB = std::move(CB),
 578                  NewName = std::move(NewName),
 579                  RenameOpts](llvm::Expected<InputsAndAST> InpAST) mutable {
 580     if (!InpAST)
 581       return CB(InpAST.takeError());
 582     // prepareRename is latency-sensitive: we don't query the index, as we
 583     // only need main-file references
 584     auto Results =
 585         clangd::rename({Pos, NewName.value_or("__clangd_rename_placeholder"),
 586                         InpAST->AST, File, /*FS=*/nullptr,
 587                         /*Index=*/nullptr, RenameOpts});
 588     if (!Results) {
 589       // LSP says to return null on failure, but that will result in a generic
 590       // failure message. If we send an LSP error response, clients can surface
 591       // the message to users (VSCode does).
 592       return CB(Results.takeError());
 593     }
 594     return CB(*Results);
 595   };
 596   WorkScheduler->runWithAST("PrepareRename", File, std::move(Action));
 597 }
 598
 599 void ClangdServer::rename(PathRef File, Position Pos, llvm::StringRef NewName,
 600                           const RenameOptions &Opts,
 601                           Callback<RenameResult> CB) {
 602   auto Action = [File = File.str(), NewName = NewName.str(), Pos, Opts,
 603                  CB = std::move(CB),
 604                  this](llvm::Expected<InputsAndAST> InpAST) mutable {
 605     // Tracks number of files edited per invocation.
 606     static constexpr trace::Metric RenameFiles("rename_files",
 607                                                trace::Metric::Distribution);
 608     if (!InpAST)
 609       return CB(InpAST.takeError());
 610     auto R = clangd::rename({Pos, NewName, InpAST->AST, File,
 611                              DirtyFS->view(std::nullopt), Index, Opts});
 612     if (!R)
 613       return CB(R.takeError());
 614
 615     if (Opts.WantFormat) {
 616       auto Style = getFormatStyleForFile(File, InpAST->Inputs.Contents,
 617                                          *InpAST->Inputs.TFS, false);
 618       llvm::Error Err = llvm::Error::success();
 619       for (auto &E : R->GlobalChanges)
 620         Err =
 621             llvm::joinErrors(reformatEdit(E.getValue(), Style), std::move(Err));
 622
 623       if (Err)
 624         return CB(std::move(Err));
 625     }
 626     RenameFiles.record(R->GlobalChanges.size());
 627     return CB(*R);
 628   };
 629   WorkScheduler->runWithAST("Rename", File, std::move(Action));
 630 }
 631
 632 namespace {
 633 // May generate several candidate selections, due to SelectionTree ambiguity.
 634 // vector of pointers because GCC doesn't like non-copyable Selection.
 635 llvm::Expected<std::vector<std::unique_ptr<Tweak::Selection>>>
 636 tweakSelection(const Range &Sel, const InputsAndAST &AST,
 637                llvm::vfs::FileSystem *FS) {
 638   auto Begin = positionToOffset(AST.Inputs.Contents, Sel.start);
 639   if (!Begin)
 640     return Begin.takeError();
 641   auto End = positionToOffset(AST.Inputs.Contents, Sel.end);
 642   if (!End)
 643     return End.takeError();
 644   std::vector<std::unique_ptr<Tweak::Selection>> Result;
 645   SelectionTree::createEach(
 646       AST.AST.getASTContext(), AST.AST.getTokens(), *Begin, *End,
 647       [&](SelectionTree T) {
 648         Result.push_back(std::make_unique<Tweak::Selection>(
 649             AST.Inputs.Index, AST.AST, *Begin, *End, std::move(T), FS));
 650         return false;
 651       });
 652   assert(!Result.empty() && "Expected at least one SelectionTree");
 653   return std::move(Result);
 654 }
 655
 656 // Some fixes may perform local renaming, we want to convert those to clangd
 657 // rename commands, such that we can leverage the index for more accurate
 658 // results.
 659 std::optional<ClangdServer::CodeActionResult::Rename>
 660 tryConvertToRename(const Diag *Diag, const Fix &Fix) {
 661   bool IsClangTidyRename = Diag->Source == Diag::ClangTidy &&
 662                            Diag->Name == "readability-identifier-naming" &&
 663                            !Fix.Edits.empty();
 664   if (IsClangTidyRename && Diag->InsideMainFile) {
 665     ClangdServer::CodeActionResult::Rename R;
 666     R.NewName = Fix.Edits.front().newText;
 667     R.FixMessage = Fix.Message;
 668     R.Diag = {Diag->Range, Diag->Message};
 669     return R;
 670   }
 671
 672   return std::nullopt;
 673 }
 674
 675 } // namespace
 676
 677 void ClangdServer::codeAction(const CodeActionInputs &Params,
 678                               Callback<CodeActionResult> CB) {
 679   auto Action = [Params, CB = std::move(CB),
 680                  FeatureModules(this->FeatureModules)](
 681                     Expected<InputsAndAST> InpAST) mutable {
 682     if (!InpAST)
 683       return CB(InpAST.takeError());
 684     auto KindAllowed =
 685         [Only(Params.RequestedActionKinds)](llvm::StringRef Kind) {
 686           if (Only.empty())
 687             return true;
 688           return llvm::any_of(Only, [&](llvm::StringRef Base) {
 689             return Kind.consume_front(Base) &&
 690                    (Kind.empty() || Kind.starts_with("."));
 691           });
 692         };
 693
 694     CodeActionResult Result;
 695     Result.Version = InpAST->AST.version().str();
 696     if (KindAllowed(CodeAction::QUICKFIX_KIND)) {
 697       auto FindMatchedDiag = [&InpAST](const DiagRef &DR) -> const Diag * {
 698         for (const auto &Diag : InpAST->AST.getDiagnostics())
 699           if (Diag.Range == DR.Range && Diag.Message == DR.Message)
 700             return &Diag;
 701         return nullptr;
 702       };
 703       for (const auto &DiagRef : Params.Diagnostics) {
 704         if (const auto *Diag = FindMatchedDiag(DiagRef))
 705           for (const auto &Fix : Diag->Fixes) {
 706             if (auto Rename = tryConvertToRename(Diag, Fix)) {
 707               Result.Renames.emplace_back(std::move(*Rename));
 708             } else {
 709               Result.QuickFixes.push_back({DiagRef, Fix});
 710             }
 711           }
 712       }
 713     }
 714
 715     // Collect Tweaks
 716     auto Selections = tweakSelection(Params.Selection, *InpAST, /*FS=*/nullptr);
 717     if (!Selections)
 718       return CB(Selections.takeError());
 719     // Don't allow a tweak to fire more than once across ambiguous selections.
 720     llvm::DenseSet<llvm::StringRef> PreparedTweaks;
 721     auto DeduplicatingFilter = [&](const Tweak &T) {
 722       return KindAllowed(T.kind()) && Params.TweakFilter(T) &&
 723              !PreparedTweaks.count(T.id());
 724     };
 725     for (const auto &Sel : *Selections) {
 726       for (auto &T : prepareTweaks(*Sel, DeduplicatingFilter, FeatureModules)) {
 727         Result.TweakRefs.push_back(TweakRef{T->id(), T->title(), T->kind()});
 728         PreparedTweaks.insert(T->id());
 729         TweakAvailable.record(1, T->id());
 730       }
 731     }
 732     CB(std::move(Result));
 733   };
 734
 735   WorkScheduler->runWithAST("codeAction", Params.File, std::move(Action),
 736                             Transient);
 737 }
 738
 739 void ClangdServer::applyTweak(PathRef File, Range Sel, StringRef TweakID,
 740                               Callback<Tweak::Effect> CB) {
 741   // Tracks number of times a tweak has been attempted.
 742   static constexpr trace::Metric TweakAttempt(
 743       "tweak_attempt", trace::Metric::Counter, "tweak_id");
 744   // Tracks number of times a tweak has failed to produce edits.
 745   static constexpr trace::Metric TweakFailed(
 746       "tweak_failed", trace::Metric::Counter, "tweak_id");
 747   TweakAttempt.record(1, TweakID);
 748   auto Action = [File = File.str(), Sel, TweakID = TweakID.str(),
 749                  CB = std::move(CB),
 750                  this](Expected<InputsAndAST> InpAST) mutable {
 751     if (!InpAST)
 752       return CB(InpAST.takeError());
 753     auto FS = DirtyFS->view(std::nullopt);
 754     auto Selections = tweakSelection(Sel, *InpAST, FS.get());
 755     if (!Selections)
 756       return CB(Selections.takeError());
 757     std::optional<llvm::Expected<Tweak::Effect>> Effect;
 758     // Try each selection, take the first one that prepare()s.
 759     // If they all fail, Effect will hold get the last error.
 760     for (const auto &Selection : *Selections) {
 761       auto T = prepareTweak(TweakID, *Selection, FeatureModules);
 762       if (T) {
 763         Effect = (*T)->apply(*Selection);
 764         break;
 765       }
 766       Effect = T.takeError();
 767     }
 768     assert(Effect && "Expected at least one selection");
 769     if (*Effect && (*Effect)->FormatEdits) {
 770       // Format tweaks that require it centrally here.
 771       for (auto &It : (*Effect)->ApplyEdits) {
 772         Edit &E = It.second;
 773         format::FormatStyle Style =
 774             getFormatStyleForFile(File, E.InitialCode, TFS, false);
 775         if (llvm::Error Err = reformatEdit(E, Style))
 776           elog("Failed to format {0}: {1}", It.first(), std::move(Err));
 777       }
 778     } else {
 779       TweakFailed.record(1, TweakID);
 780     }
 781     return CB(std::move(*Effect));
 782   };
 783   WorkScheduler->runWithAST("ApplyTweak", File, std::move(Action));
 784 }
 785
 786 void ClangdServer::locateSymbolAt(PathRef File, Position Pos,
 787                                   Callback<std::vector<LocatedSymbol>> CB) {
 788   auto Action = [Pos, CB = std::move(CB),
 789                  this](llvm::Expected<InputsAndAST> InpAST) mutable {
 790     if (!InpAST)
 791       return CB(InpAST.takeError());
 792     CB(clangd::locateSymbolAt(InpAST->AST, Pos, Index));
 793   };
 794
 795   WorkScheduler->runWithAST("Definitions", File, std::move(Action));
 796 }
 797
 798 void ClangdServer::switchSourceHeader(
 799     PathRef Path, Callback<std::optional<clangd::Path>> CB) {
 800   // We want to return the result as fast as possible, strategy is:
 801   //  1) use the file-only heuristic, it requires some IO but it is much
 802   //     faster than building AST, but it only works when .h/.cc files are in
 803   //     the same directory.
 804   //  2) if 1) fails, we use the AST&Index approach, it is slower but supports
 805   //     different code layout.
 806   if (auto CorrespondingFile =
 807           getCorrespondingHeaderOrSource(Path, TFS.view(std::nullopt)))
 808     return CB(std::move(CorrespondingFile));
 809   auto Action = [Path = Path.str(), CB = std::move(CB),
 810                  this](llvm::Expected<InputsAndAST> InpAST) mutable {
 811     if (!InpAST)
 812       return CB(InpAST.takeError());
 813     CB(getCorrespondingHeaderOrSource(Path, InpAST->AST, Index));
 814   };
 815   WorkScheduler->runWithAST("SwitchHeaderSource", Path, std::move(Action));
 816 }
 817
 818 void ClangdServer::findDocumentHighlights(
 819     PathRef File, Position Pos, Callback<std::vector<DocumentHighlight>> CB) {
 820   auto Action =
 821       [Pos, CB = std::move(CB)](llvm::Expected<InputsAndAST> InpAST) mutable {
 822         if (!InpAST)
 823           return CB(InpAST.takeError());
 824         CB(clangd::findDocumentHighlights(InpAST->AST, Pos));
 825       };
 826
 827   WorkScheduler->runWithAST("Highlights", File, std::move(Action), Transient);
 828 }
 829
 830 void ClangdServer::findHover(PathRef File, Position Pos,
 831                              Callback<std::optional<HoverInfo>> CB) {
 832   auto Action = [File = File.str(), Pos, CB = std::move(CB),
 833                  this](llvm::Expected<InputsAndAST> InpAST) mutable {
 834     if (!InpAST)
 835       return CB(InpAST.takeError());
 836     format::FormatStyle Style = getFormatStyleForFile(
 837         File, InpAST->Inputs.Contents, *InpAST->Inputs.TFS, false);
 838     CB(clangd::getHover(InpAST->AST, Pos, std::move(Style), Index));
 839   };
 840
 841   WorkScheduler->runWithAST("Hover", File, std::move(Action), Transient);
 842 }
 843
 844 void ClangdServer::typeHierarchy(PathRef File, Position Pos, int Resolve,
 845                                  TypeHierarchyDirection Direction,
 846                                  Callback<std::vector<TypeHierarchyItem>> CB) {
 847   auto Action = [File = File.str(), Pos, Resolve, Direction, CB = std::move(CB),
 848                  this](Expected<InputsAndAST> InpAST) mutable {
 849     if (!InpAST)
 850       return CB(InpAST.takeError());
 851     CB(clangd::getTypeHierarchy(InpAST->AST, Pos, Resolve, Direction, Index,
 852                                 File));
 853   };
 854
 855   WorkScheduler->runWithAST("TypeHierarchy", File, std::move(Action));
 856 }
 857
 858 void ClangdServer::superTypes(
 859     const TypeHierarchyItem &Item,
 860     Callback<std::optional<std::vector<TypeHierarchyItem>>> CB) {
 861   WorkScheduler->run("typeHierarchy/superTypes", /*Path=*/"",
 862                      [=, CB = std::move(CB)]() mutable {
 863                        CB(clangd::superTypes(Item, Index));
 864                      });
 865 }
 866
 867 void ClangdServer::subTypes(const TypeHierarchyItem &Item,
 868                             Callback<std::vector<TypeHierarchyItem>> CB) {
 869   WorkScheduler->run(
 870       "typeHierarchy/subTypes", /*Path=*/"",
 871       [=, CB = std::move(CB)]() mutable { CB(clangd::subTypes(Item, Index)); });
 872 }
 873
 874 void ClangdServer::resolveTypeHierarchy(
 875     TypeHierarchyItem Item, int Resolve, TypeHierarchyDirection Direction,
 876     Callback<std::optional<TypeHierarchyItem>> CB) {
 877   WorkScheduler->run(
 878       "Resolve Type Hierarchy", "", [=, CB = std::move(CB)]() mutable {
 879         clangd::resolveTypeHierarchy(Item, Resolve, Direction, Index);
 880         CB(Item);
 881       });
 882 }
 883
 884 void ClangdServer::prepareCallHierarchy(
 885     PathRef File, Position Pos, Callback<std::vector<CallHierarchyItem>> CB) {
 886   auto Action = [File = File.str(), Pos,
 887                  CB = std::move(CB)](Expected<InputsAndAST> InpAST) mutable {
 888     if (!InpAST)
 889       return CB(InpAST.takeError());
 890     CB(clangd::prepareCallHierarchy(InpAST->AST, Pos, File));
 891   };
 892   WorkScheduler->runWithAST("CallHierarchy", File, std::move(Action));
 893 }
 894
 895 void ClangdServer::incomingCalls(
 896     const CallHierarchyItem &Item,
 897     Callback<std::vector<CallHierarchyIncomingCall>> CB) {
 898   WorkScheduler->run("Incoming Calls", "",
 899                      [CB = std::move(CB), Item, this]() mutable {
 900                        CB(clangd::incomingCalls(Item, Index));
 901                      });
 902 }
 903
 904 void ClangdServer::inlayHints(PathRef File, std::optional<Range> RestrictRange,
 905                               Callback<std::vector<InlayHint>> CB) {
 906   auto Action = [RestrictRange(std::move(RestrictRange)),
 907                  CB = std::move(CB)](Expected<InputsAndAST> InpAST) mutable {
 908     if (!InpAST)
 909       return CB(InpAST.takeError());
 910     CB(clangd::inlayHints(InpAST->AST, std::move(RestrictRange)));
 911   };
 912   WorkScheduler->runWithAST("InlayHints", File, std::move(Action), Transient);
 913 }
 914
 915 void ClangdServer::onFileEvent(const DidChangeWatchedFilesParams &Params) {
 916   // FIXME: Do nothing for now. This will be used for indexing and potentially
 917   // invalidating other caches.
 918 }
 919
 920 void ClangdServer::workspaceSymbols(
 921     llvm::StringRef Query, int Limit,
 922     Callback<std::vector<SymbolInformation>> CB) {
 923   WorkScheduler->run(
 924       "getWorkspaceSymbols", /*Path=*/"",
 925       [Query = Query.str(), Limit, CB = std::move(CB), this]() mutable {
 926         CB(clangd::getWorkspaceSymbols(Query, Limit, Index,
 927                                        WorkspaceRoot.value_or("")));
 928       });
 929 }
 930
 931 void ClangdServer::documentSymbols(llvm::StringRef File,
 932                                    Callback<std::vector<DocumentSymbol>> CB) {
 933   auto Action =
 934       [CB = std::move(CB)](llvm::Expected<InputsAndAST> InpAST) mutable {
 935         if (!InpAST)
 936           return CB(InpAST.takeError());
 937         CB(clangd::getDocumentSymbols(InpAST->AST));
 938       };
 939   WorkScheduler->runWithAST("DocumentSymbols", File, std::move(Action),
 940                             Transient);
 941 }
 942
 943 void ClangdServer::foldingRanges(llvm::StringRef File,
 944                                  Callback<std::vector<FoldingRange>> CB) {
 945   auto Code = getDraft(File);
 946   if (!Code)
 947     return CB(llvm::make_error<LSPError>(
 948         "trying to compute folding ranges for non-added document",
 949         ErrorCode::InvalidParams));
 950   auto Action = [LineFoldingOnly = LineFoldingOnly, CB = std::move(CB),
 951                  Code = std::move(*Code)]() mutable {
 952     CB(clangd::getFoldingRanges(Code, LineFoldingOnly));
 953   };
 954   // We want to make sure folding ranges are always available for all the open
 955   // files, hence prefer runQuick to not wait for operations on other files.
 956   WorkScheduler->runQuick("FoldingRanges", File, std::move(Action));
 957 }
 958
 959 void ClangdServer::findType(llvm::StringRef File, Position Pos,
 960                             Callback<std::vector<LocatedSymbol>> CB) {
 961   auto Action = [Pos, CB = std::move(CB),
 962                  this](llvm::Expected<InputsAndAST> InpAST) mutable {
 963     if (!InpAST)
 964       return CB(InpAST.takeError());
 965     CB(clangd::findType(InpAST->AST, Pos, Index));
 966   };
 967   WorkScheduler->runWithAST("FindType", File, std::move(Action));
 968 }
 969
 970 void ClangdServer::findImplementations(
 971     PathRef File, Position Pos, Callback<std::vector<LocatedSymbol>> CB) {
 972   auto Action = [Pos, CB = std::move(CB),
 973                  this](llvm::Expected<InputsAndAST> InpAST) mutable {
 974     if (!InpAST)
 975       return CB(InpAST.takeError());
 976     CB(clangd::findImplementations(InpAST->AST, Pos, Index));
 977   };
 978
 979   WorkScheduler->runWithAST("Implementations", File, std::move(Action));
 980 }
 981
 982 void ClangdServer::findReferences(PathRef File, Position Pos, uint32_t Limit,
 983                                   bool AddContainer,
 984                                   Callback<ReferencesResult> CB) {
 985   auto Action = [Pos, Limit, AddContainer, CB = std::move(CB),
 986                  this](llvm::Expected<InputsAndAST> InpAST) mutable {
 987     if (!InpAST)
 988       return CB(InpAST.takeError());
 989     CB(clangd::findReferences(InpAST->AST, Pos, Limit, Index, AddContainer));
 990   };
 991
 992   WorkScheduler->runWithAST("References", File, std::move(Action));
 993 }
 994
 995 void ClangdServer::symbolInfo(PathRef File, Position Pos,
 996                               Callback<std::vector<SymbolDetails>> CB) {
 997   auto Action =
 998       [Pos, CB = std::move(CB)](llvm::Expected<InputsAndAST> InpAST) mutable {
 999         if (!InpAST)
1000           return CB(InpAST.takeError());
1001         CB(clangd::getSymbolInfo(InpAST->AST, Pos));
1002       };
1003
1004   WorkScheduler->runWithAST("SymbolInfo", File, std::move(Action));
1005 }
1006
1007 void ClangdServer::semanticRanges(PathRef File,
1008                                   const std::vector<Position> &Positions,
1009                                   Callback<std::vector<SelectionRange>> CB) {
1010   auto Action = [Positions, CB = std::move(CB)](
1011                     llvm::Expected<InputsAndAST> InpAST) mutable {
1012     if (!InpAST)
1013       return CB(InpAST.takeError());
1014     std::vector<SelectionRange> Result;
1015     for (const auto &Pos : Positions) {
1016       if (auto Range = clangd::getSemanticRanges(InpAST->AST, Pos))
1017         Result.push_back(std::move(*Range));
1018       else
1019         return CB(Range.takeError());
1020     }
1021     CB(std::move(Result));
1022   };
1023   WorkScheduler->runWithAST("SemanticRanges", File, std::move(Action));
1024 }
1025
1026 void ClangdServer::documentLinks(PathRef File,
1027                                  Callback<std::vector<DocumentLink>> CB) {
1028   auto Action =
1029       [CB = std::move(CB)](llvm::Expected<InputsAndAST> InpAST) mutable {
1030         if (!InpAST)
1031           return CB(InpAST.takeError());
1032         CB(clangd::getDocumentLinks(InpAST->AST));
1033       };
1034   WorkScheduler->runWithAST("DocumentLinks", File, std::move(Action),
1035                             Transient);
1036 }
1037
1038 void ClangdServer::semanticHighlights(
1039     PathRef File, Callback<std::vector<HighlightingToken>> CB) {
1040
1041   auto Action = [CB = std::move(CB),
1042                  PublishInactiveRegions = PublishInactiveRegions](
1043                     llvm::Expected<InputsAndAST> InpAST) mutable {
1044     if (!InpAST)
1045       return CB(InpAST.takeError());
1046     // Include inactive regions in semantic highlighting tokens only if the
1047     // client doesn't support a dedicated protocol for being informed about
1048     // them.
1049     CB(clangd::getSemanticHighlightings(InpAST->AST, !PublishInactiveRegions));
1050   };
1051   WorkScheduler->runWithAST("SemanticHighlights", File, std::move(Action),
1052                             Transient);
1053 }
1054
1055 void ClangdServer::getAST(PathRef File, std::optional<Range> R,
1056                           Callback<std::optional<ASTNode>> CB) {
1057   auto Action =
1058       [R, CB(std::move(CB))](llvm::Expected<InputsAndAST> Inputs) mutable {
1059         if (!Inputs)
1060           return CB(Inputs.takeError());
1061         if (!R) {
1062           // It's safe to pass in the TU, as dumpAST() does not
1063           // deserialize the preamble.
1064           auto Node = DynTypedNode::create(
1065               *Inputs->AST.getASTContext().getTranslationUnitDecl());
1066           return CB(dumpAST(Node, Inputs->AST.getTokens(),
1067                             Inputs->AST.getASTContext()));
1068         }
1069         unsigned Start, End;
1070         if (auto Offset = positionToOffset(Inputs->Inputs.Contents, R->start))
1071           Start = *Offset;
1072         else
1073           return CB(Offset.takeError());
1074         if (auto Offset = positionToOffset(Inputs->Inputs.Contents, R->end))
1075           End = *Offset;
1076         else
1077           return CB(Offset.takeError());
1078         bool Success = SelectionTree::createEach(
1079             Inputs->AST.getASTContext(), Inputs->AST.getTokens(), Start, End,
1080             [&](SelectionTree T) {
1081               if (const SelectionTree::Node *N = T.commonAncestor()) {
1082                 CB(dumpAST(N->ASTNode, Inputs->AST.getTokens(),
1083                            Inputs->AST.getASTContext()));
1084                 return true;
1085               }
1086               return false;
1087             });
1088         if (!Success)
1089           CB(std::nullopt);
1090       };
1091   WorkScheduler->runWithAST("GetAST", File, std::move(Action));
1092 }
1093
1094 void ClangdServer::customAction(PathRef File, llvm::StringRef Name,
1095                                 Callback<InputsAndAST> Action) {
1096   WorkScheduler->runWithAST(Name, File, std::move(Action));
1097 }
1098
1099 void ClangdServer::diagnostics(PathRef File, Callback<std::vector<Diag>> CB) {
1100   auto Action =
1101       [CB = std::move(CB)](llvm::Expected<InputsAndAST> InpAST) mutable {
1102         if (!InpAST)
1103           return CB(InpAST.takeError());
1104         return CB(InpAST->AST.getDiagnostics());
1105       };
1106
1107   WorkScheduler->runWithAST("Diagnostics", File, std::move(Action));
1108 }
1109
1110 llvm::StringMap<TUScheduler::FileStats> ClangdServer::fileStats() const {
1111   return WorkScheduler->fileStats();
1112 }
1113
1114 [[nodiscard]] bool
1115 ClangdServer::blockUntilIdleForTest(std::optional<double> TimeoutSeconds) {
1116   // Order is important here: we don't want to block on A and then B,
1117   // if B might schedule work on A.
1118
1119 #if defined(__has_feature) &&                                                  \
1120     (__has_feature(address_sanitizer) || __has_feature(hwaddress_sanitizer) || \
1121      __has_feature(memory_sanitizer) || __has_feature(thread_sanitizer))
1122   if (TimeoutSeconds.has_value())
1123     (*TimeoutSeconds) *= 10;
1124 #endif
1125
1126   // Nothing else can schedule work on TUScheduler, because it's not threadsafe
1127   // and we're blocking the main thread.
1128   if (!WorkScheduler->blockUntilIdle(timeoutSeconds(TimeoutSeconds)))
1129     return false;
1130   // TUScheduler is the only thing that starts background indexing work.
1131   if (IndexTasks && !IndexTasks->wait(timeoutSeconds(TimeoutSeconds)))
1132     return false;
1133
1134   // Unfortunately we don't have strict topological order between the rest of
1135   // the components. E.g. CDB broadcast triggers backrgound indexing.
1136   // This queries the CDB which may discover new work if disk has changed.
1137   //
1138   // So try each one a few times in a loop.
1139   // If there are no tricky interactions then all after the first are no-ops.
1140   // Then on the last iteration, verify they're idle without waiting.
1141   //
1142   // There's a small chance they're juggling work and we didn't catch them :-(
1143   for (std::optional<double> Timeout :
1144        {TimeoutSeconds, TimeoutSeconds, std::optional<double>(0)}) {
1145     if (!CDB.blockUntilIdle(timeoutSeconds(Timeout)))
1146       return false;
1147     if (BackgroundIdx && !BackgroundIdx->blockUntilIdleForTest(Timeout))
1148       return false;
1149     if (FeatureModules && llvm::any_of(*FeatureModules, [&](FeatureModule &M) {
1150           return !M.blockUntilIdle(timeoutSeconds(Timeout));
1151         }))
1152       return false;
1153   }
1154
1155   assert(WorkScheduler->blockUntilIdle(Deadline::zero()) &&
1156          "Something scheduled work while we're blocking the main thread!");
1157   return true;
1158 }
1159
1160 void ClangdServer::profile(MemoryTree &MT) const {
1161   if (DynamicIdx)
1162     DynamicIdx->profile(MT.child("dynamic_index"));
1163   if (BackgroundIdx)
1164     BackgroundIdx->profile(MT.child("background_index"));
1165   WorkScheduler->profile(MT.child("tuscheduler"));
1166 }
1167 } // namespace clangd
1168 } // namespace clang