clang-tools-extra/clangd/ClangdLSPServer.cpp

   1 //===--- ClangdLSPServer.cpp - LSP server ------------------------*- 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 "ClangdLSPServer.h"
  10 #include "ClangdServer.h"
  11 #include "CodeComplete.h"
  12 #include "CompileCommands.h"
  13 #include "Diagnostics.h"
  14 #include "Feature.h"
  15 #include "GlobalCompilationDatabase.h"
  16 #include "LSPBinder.h"
  17 #include "ModulesBuilder.h"
  18 #include "Protocol.h"
  19 #include "SemanticHighlighting.h"
  20 #include "SourceCode.h"
  21 #include "TUScheduler.h"
  22 #include "URI.h"
  23 #include "refactor/Tweak.h"
  24 #include "support/Cancellation.h"
  25 #include "support/Context.h"
  26 #include "support/MemoryTree.h"
  27 #include "support/Trace.h"
  28 #include "clang/Tooling/Core/Replacement.h"
  29 #include "llvm/ADT/ArrayRef.h"
  30 #include "llvm/ADT/FunctionExtras.h"
  31 #include "llvm/ADT/ScopeExit.h"
  32 #include "llvm/ADT/StringRef.h"
  33 #include "llvm/ADT/Twine.h"
  34 #include "llvm/Support/Allocator.h"
  35 #include "llvm/Support/Error.h"
  36 #include "llvm/Support/FormatVariadic.h"
  37 #include "llvm/Support/JSON.h"
  38 #include "llvm/Support/SHA1.h"
  39 #include "llvm/Support/ScopedPrinter.h"
  40 #include "llvm/Support/raw_ostream.h"
  41 #include <chrono>
  42 #include <cstddef>
  43 #include <cstdint>
  44 #include <functional>
  45 #include <map>
  46 #include <memory>
  47 #include <mutex>
  48 #include <optional>
  49 #include <string>
  50 #include <utility>
  51 #include <vector>
  52
  53 namespace clang {
  54 namespace clangd {
  55
  56 namespace {
  57 // Tracks end-to-end latency of high level lsp calls. Measurements are in
  58 // seconds.
  59 constexpr trace::Metric LSPLatency("lsp_latency", trace::Metric::Distribution,
  60                                    "method_name");
  61
  62 // LSP defines file versions as numbers that increase.
  63 // ClangdServer treats them as opaque and therefore uses strings instead.
  64 std::string encodeVersion(std::optional<int64_t> LSPVersion) {
  65   return LSPVersion ? llvm::to_string(*LSPVersion) : "";
  66 }
  67 std::optional<int64_t> decodeVersion(llvm::StringRef Encoded) {
  68   int64_t Result;
  69   if (llvm::to_integer(Encoded, Result, 10))
  70     return Result;
  71   if (!Encoded.empty()) // Empty can be e.g. diagnostics on close.
  72     elog("unexpected non-numeric version {0}", Encoded);
  73   return std::nullopt;
  74 }
  75
  76 const llvm::StringLiteral ApplyFixCommand = "clangd.applyFix";
  77 const llvm::StringLiteral ApplyTweakCommand = "clangd.applyTweak";
  78 const llvm::StringLiteral ApplyRenameCommand = "clangd.applyRename";
  79
  80 CodeAction toCodeAction(const ClangdServer::CodeActionResult::Rename &R,
  81                         const URIForFile &File) {
  82   CodeAction CA;
  83   CA.title = R.FixMessage;
  84   CA.kind = std::string(CodeAction::REFACTOR_KIND);
  85   CA.command.emplace();
  86   CA.command->title = R.FixMessage;
  87   CA.command->command = std::string(ApplyRenameCommand);
  88   RenameParams Params;
  89   Params.textDocument = TextDocumentIdentifier{File};
  90   Params.position = R.Diag.Range.start;
  91   Params.newName = R.NewName;
  92   CA.command->argument = Params;
  93   return CA;
  94 }
  95
  96 /// Transforms a tweak into a code action that would apply it if executed.
  97 /// EXPECTS: T.prepare() was called and returned true.
  98 CodeAction toCodeAction(const ClangdServer::TweakRef &T, const URIForFile &File,
  99                         Range Selection) {
 100   CodeAction CA;
 101   CA.title = T.Title;
 102   CA.kind = T.Kind.str();
 103   // This tweak may have an expensive second stage, we only run it if the user
 104   // actually chooses it in the UI. We reply with a command that would run the
 105   // corresponding tweak.
 106   // FIXME: for some tweaks, computing the edits is cheap and we could send them
 107   //        directly.
 108   CA.command.emplace();
 109   CA.command->title = T.Title;
 110   CA.command->command = std::string(ApplyTweakCommand);
 111   TweakArgs Args;
 112   Args.file = File;
 113   Args.tweakID = T.ID;
 114   Args.selection = Selection;
 115   CA.command->argument = std::move(Args);
 116   return CA;
 117 }
 118
 119 /// Convert from Fix to LSP CodeAction.
 120 CodeAction toCodeAction(const Fix &F, const URIForFile &File,
 121                         const std::optional<int64_t> &Version,
 122                         bool SupportsDocumentChanges,
 123                         bool SupportChangeAnnotation) {
 124   CodeAction Action;
 125   Action.title = F.Message;
 126   Action.kind = std::string(CodeAction::QUICKFIX_KIND);
 127   Action.edit.emplace();
 128   if (!SupportsDocumentChanges) {
 129     Action.edit->changes.emplace();
 130     auto &Changes = (*Action.edit->changes)[File.uri()];
 131     for (const auto &E : F.Edits)
 132       Changes.push_back({E.range, E.newText, /*annotationId=*/""});
 133   } else {
 134     Action.edit->documentChanges.emplace();
 135     TextDocumentEdit &Edit = Action.edit->documentChanges->emplace_back();
 136     Edit.textDocument = VersionedTextDocumentIdentifier{{File}, Version};
 137     for (const auto &E : F.Edits)
 138       Edit.edits.push_back(
 139           {E.range, E.newText,
 140            SupportChangeAnnotation ? E.annotationId : ""});
 141     if (SupportChangeAnnotation) {
 142       for (const auto &[AID, Annotation]: F.Annotations)
 143         Action.edit->changeAnnotations[AID] = Annotation;
 144     }
 145   }
 146   return Action;
 147 }
 148
 149 void adjustSymbolKinds(llvm::MutableArrayRef<DocumentSymbol> Syms,
 150                        SymbolKindBitset Kinds) {
 151   for (auto &S : Syms) {
 152     S.kind = adjustKindToCapability(S.kind, Kinds);
 153     adjustSymbolKinds(S.children, Kinds);
 154   }
 155 }
 156
 157 SymbolKindBitset defaultSymbolKinds() {
 158   SymbolKindBitset Defaults;
 159   for (size_t I = SymbolKindMin; I <= static_cast<size_t>(SymbolKind::Array);
 160        ++I)
 161     Defaults.set(I);
 162   return Defaults;
 163 }
 164
 165 CompletionItemKindBitset defaultCompletionItemKinds() {
 166   CompletionItemKindBitset Defaults;
 167   for (size_t I = CompletionItemKindMin;
 168        I <= static_cast<size_t>(CompletionItemKind::Reference); ++I)
 169     Defaults.set(I);
 170   return Defaults;
 171 }
 172
 173 // Makes sure edits in \p FE are applicable to latest file contents reported by
 174 // editor. If not generates an error message containing information about files
 175 // that needs to be saved.
 176 llvm::Error validateEdits(const ClangdServer &Server, const FileEdits &FE) {
 177   size_t InvalidFileCount = 0;
 178   llvm::StringRef LastInvalidFile;
 179   for (const auto &It : FE) {
 180     if (auto Draft = Server.getDraft(It.first())) {
 181       // If the file is open in user's editor, make sure the version we
 182       // saw and current version are compatible as this is the text that
 183       // will be replaced by editors.
 184       if (!It.second.canApplyTo(*Draft)) {
 185         ++InvalidFileCount;
 186         LastInvalidFile = It.first();
 187       }
 188     }
 189   }
 190   if (!InvalidFileCount)
 191     return llvm::Error::success();
 192   if (InvalidFileCount == 1)
 193     return error("File must be saved first: {0}", LastInvalidFile);
 194   return error("Files must be saved first: {0} (and {1} others)",
 195                LastInvalidFile, InvalidFileCount - 1);
 196 }
 197 } // namespace
 198
 199 // MessageHandler dispatches incoming LSP messages.
 200 // It handles cross-cutting concerns:
 201 //  - serializes/deserializes protocol objects to JSON
 202 //  - logging of inbound messages
 203 //  - cancellation handling
 204 //  - basic call tracing
 205 // MessageHandler ensures that initialize() is called before any other handler.
 206 class ClangdLSPServer::MessageHandler : public Transport::MessageHandler {
 207 public:
 208   MessageHandler(ClangdLSPServer &Server) : Server(Server) {}
 209
 210   bool onNotify(llvm::StringRef Method, llvm::json::Value Params) override {
 211     trace::Span Tracer(Method, LSPLatency);
 212     SPAN_ATTACH(Tracer, "Params", Params);
 213     WithContext HandlerContext(handlerContext());
 214     log("<-- {0}", Method);
 215     if (Method == "exit")
 216       return false;
 217     auto Handler = Server.Handlers.NotificationHandlers.find(Method);
 218     if (Handler != Server.Handlers.NotificationHandlers.end()) {
 219       Handler->second(std::move(Params));
 220       Server.maybeExportMemoryProfile();
 221       Server.maybeCleanupMemory();
 222     } else if (!Server.Server) {
 223       elog("Notification {0} before initialization", Method);
 224     } else if (Method == "$/cancelRequest") {
 225       onCancel(std::move(Params));
 226     } else {
 227       log("unhandled notification {0}", Method);
 228     }
 229     return true;
 230   }
 231
 232   bool onCall(llvm::StringRef Method, llvm::json::Value Params,
 233               llvm::json::Value ID) override {
 234     WithContext HandlerContext(handlerContext());
 235     // Calls can be canceled by the client. Add cancellation context.
 236     WithContext WithCancel(cancelableRequestContext(ID));
 237     trace::Span Tracer(Method, LSPLatency);
 238     SPAN_ATTACH(Tracer, "Params", Params);
 239     ReplyOnce Reply(ID, Method, &Server, Tracer.Args);
 240     log("<-- {0}({1})", Method, ID);
 241     auto Handler = Server.Handlers.MethodHandlers.find(Method);
 242     if (Handler != Server.Handlers.MethodHandlers.end()) {
 243       Handler->second(std::move(Params), std::move(Reply));
 244     } else if (!Server.Server) {
 245       elog("Call {0} before initialization.", Method);
 246       Reply(llvm::make_error<LSPError>("server not initialized",
 247                                        ErrorCode::ServerNotInitialized));
 248     } else {
 249       Reply(llvm::make_error<LSPError>("method not found",
 250                                        ErrorCode::MethodNotFound));
 251     }
 252     return true;
 253   }
 254
 255   bool onReply(llvm::json::Value ID,
 256                llvm::Expected<llvm::json::Value> Result) override {
 257     WithContext HandlerContext(handlerContext());
 258
 259     Callback<llvm::json::Value> ReplyHandler = nullptr;
 260     if (auto IntID = ID.getAsInteger()) {
 261       std::lock_guard<std::mutex> Mutex(CallMutex);
 262       // Find a corresponding callback for the request ID;
 263       for (size_t Index = 0; Index < ReplyCallbacks.size(); ++Index) {
 264         if (ReplyCallbacks[Index].first == *IntID) {
 265           ReplyHandler = std::move(ReplyCallbacks[Index].second);
 266           ReplyCallbacks.erase(ReplyCallbacks.begin() +
 267                                Index); // remove the entry
 268           break;
 269         }
 270       }
 271     }
 272
 273     if (!ReplyHandler) {
 274       // No callback being found, use a default log callback.
 275       ReplyHandler = [&ID](llvm::Expected<llvm::json::Value> Result) {
 276         elog("received a reply with ID {0}, but there was no such call", ID);
 277         if (!Result)
 278           llvm::consumeError(Result.takeError());
 279       };
 280     }
 281
 282     // Log and run the reply handler.
 283     if (Result) {
 284       log("<-- reply({0})", ID);
 285       ReplyHandler(std::move(Result));
 286     } else {
 287       auto Err = Result.takeError();
 288       log("<-- reply({0}) error: {1}", ID, Err);
 289       ReplyHandler(std::move(Err));
 290     }
 291     return true;
 292   }
 293
 294   // Bind a reply callback to a request. The callback will be invoked when
 295   // clangd receives the reply from the LSP client.
 296   // Return a call id of the request.
 297   llvm::json::Value bindReply(Callback<llvm::json::Value> Reply) {
 298     std::optional<std::pair<int, Callback<llvm::json::Value>>> OldestCB;
 299     int ID;
 300     {
 301       std::lock_guard<std::mutex> Mutex(CallMutex);
 302       ID = NextCallID++;
 303       ReplyCallbacks.emplace_back(ID, std::move(Reply));
 304
 305       // If the queue overflows, we assume that the client didn't reply the
 306       // oldest request, and run the corresponding callback which replies an
 307       // error to the client.
 308       if (ReplyCallbacks.size() > MaxReplayCallbacks) {
 309         elog("more than {0} outstanding LSP calls, forgetting about {1}",
 310              MaxReplayCallbacks, ReplyCallbacks.front().first);
 311         OldestCB = std::move(ReplyCallbacks.front());
 312         ReplyCallbacks.pop_front();
 313       }
 314     }
 315     if (OldestCB)
 316       OldestCB->second(
 317           error("failed to receive a client reply for request ({0})",
 318                 OldestCB->first));
 319     return ID;
 320   }
 321
 322 private:
 323   // Function object to reply to an LSP call.
 324   // Each instance must be called exactly once, otherwise:
 325   //  - the bug is logged, and (in debug mode) an assert will fire
 326   //  - if there was no reply, an error reply is sent
 327   //  - if there were multiple replies, only the first is sent
 328   class ReplyOnce {
 329     std::atomic<bool> Replied = {false};
 330     std::chrono::steady_clock::time_point Start;
 331     llvm::json::Value ID;
 332     std::string Method;
 333     ClangdLSPServer *Server; // Null when moved-from.
 334     llvm::json::Object *TraceArgs;
 335
 336   public:
 337     ReplyOnce(const llvm::json::Value &ID, llvm::StringRef Method,
 338               ClangdLSPServer *Server, llvm::json::Object *TraceArgs)
 339         : Start(std::chrono::steady_clock::now()), ID(ID), Method(Method),
 340           Server(Server), TraceArgs(TraceArgs) {
 341       assert(Server);
 342     }
 343     ReplyOnce(ReplyOnce &&Other)
 344         : Replied(Other.Replied.load()), Start(Other.Start),
 345           ID(std::move(Other.ID)), Method(std::move(Other.Method)),
 346           Server(Other.Server), TraceArgs(Other.TraceArgs) {
 347       Other.Server = nullptr;
 348     }
 349     ReplyOnce &operator=(ReplyOnce &&) = delete;
 350     ReplyOnce(const ReplyOnce &) = delete;
 351     ReplyOnce &operator=(const ReplyOnce &) = delete;
 352
 353     ~ReplyOnce() {
 354       // There's one legitimate reason to never reply to a request: clangd's
 355       // request handler send a call to the client (e.g. applyEdit) and the
 356       // client never replied. In this case, the ReplyOnce is owned by
 357       // ClangdLSPServer's reply callback table and is destroyed along with the
 358       // server. We don't attempt to send a reply in this case, there's little
 359       // to be gained from doing so.
 360       if (Server && !Server->IsBeingDestroyed && !Replied) {
 361         elog("No reply to message {0}({1})", Method, ID);
 362         assert(false && "must reply to all calls!");
 363         (*this)(llvm::make_error<LSPError>("server failed to reply",
 364                                            ErrorCode::InternalError));
 365       }
 366     }
 367
 368     void operator()(llvm::Expected<llvm::json::Value> Reply) {
 369       assert(Server && "moved-from!");
 370       if (Replied.exchange(true)) {
 371         elog("Replied twice to message {0}({1})", Method, ID);
 372         assert(false && "must reply to each call only once!");
 373         return;
 374       }
 375       auto Duration = std::chrono::steady_clock::now() - Start;
 376       if (Reply) {
 377         log("--> reply:{0}({1}) {2:ms}", Method, ID, Duration);
 378         if (TraceArgs)
 379           (*TraceArgs)["Reply"] = *Reply;
 380         std::lock_guard<std::mutex> Lock(Server->TranspWriter);
 381         Server->Transp.reply(std::move(ID), std::move(Reply));
 382       } else {
 383         llvm::Error Err = Reply.takeError();
 384         log("--> reply:{0}({1}) {2:ms}, error: {3}", Method, ID, Duration, Err);
 385         if (TraceArgs)
 386           (*TraceArgs)["Error"] = llvm::to_string(Err);
 387         std::lock_guard<std::mutex> Lock(Server->TranspWriter);
 388         Server->Transp.reply(std::move(ID), std::move(Err));
 389       }
 390     }
 391   };
 392
 393   // Method calls may be cancelled by ID, so keep track of their state.
 394   // This needs a mutex: handlers may finish on a different thread, and that's
 395   // when we clean up entries in the map.
 396   mutable std::mutex RequestCancelersMutex;
 397   llvm::StringMap<std::pair<Canceler, /*Cookie*/ unsigned>> RequestCancelers;
 398   unsigned NextRequestCookie = 0; // To disambiguate reused IDs, see below.
 399   void onCancel(const llvm::json::Value &Params) {
 400     const llvm::json::Value *ID = nullptr;
 401     if (auto *O = Params.getAsObject())
 402       ID = O->get("id");
 403     if (!ID) {
 404       elog("Bad cancellation request: {0}", Params);
 405       return;
 406     }
 407     auto StrID = llvm::to_string(*ID);
 408     std::lock_guard<std::mutex> Lock(RequestCancelersMutex);
 409     auto It = RequestCancelers.find(StrID);
 410     if (It != RequestCancelers.end())
 411       It->second.first(); // Invoke the canceler.
 412   }
 413
 414   Context handlerContext() const {
 415     return Context::current().derive(
 416         kCurrentOffsetEncoding,
 417         Server.Opts.Encoding.value_or(OffsetEncoding::UTF16));
 418   }
 419
 420   // We run cancelable requests in a context that does two things:
 421   //  - allows cancellation using RequestCancelers[ID]
 422   //  - cleans up the entry in RequestCancelers when it's no longer needed
 423   // If a client reuses an ID, the last wins and the first cannot be canceled.
 424   Context cancelableRequestContext(const llvm::json::Value &ID) {
 425     auto Task = cancelableTask(
 426         /*Reason=*/static_cast<int>(ErrorCode::RequestCancelled));
 427     auto StrID = llvm::to_string(ID);  // JSON-serialize ID for map key.
 428     auto Cookie = NextRequestCookie++; // No lock, only called on main thread.
 429     {
 430       std::lock_guard<std::mutex> Lock(RequestCancelersMutex);
 431       RequestCancelers[StrID] = {std::move(Task.second), Cookie};
 432     }
 433     // When the request ends, we can clean up the entry we just added.
 434     // The cookie lets us check that it hasn't been overwritten due to ID
 435     // reuse.
 436     return Task.first.derive(llvm::make_scope_exit([this, StrID, Cookie] {
 437       std::lock_guard<std::mutex> Lock(RequestCancelersMutex);
 438       auto It = RequestCancelers.find(StrID);
 439       if (It != RequestCancelers.end() && It->second.second == Cookie)
 440         RequestCancelers.erase(It);
 441     }));
 442   }
 443
 444   // The maximum number of callbacks held in clangd.
 445   //
 446   // We bound the maximum size to the pending map to prevent memory leakage
 447   // for cases where LSP clients don't reply for the request.
 448   // This has to go after RequestCancellers and RequestCancellersMutex since it
 449   // can contain a callback that has a cancelable context.
 450   static constexpr int MaxReplayCallbacks = 100;
 451   mutable std::mutex CallMutex;
 452   int NextCallID = 0; /* GUARDED_BY(CallMutex) */
 453   std::deque<std::pair</*RequestID*/ int,
 454                        /*ReplyHandler*/ Callback<llvm::json::Value>>>
 455       ReplyCallbacks; /* GUARDED_BY(CallMutex) */
 456
 457   ClangdLSPServer &Server;
 458 };
 459 constexpr int ClangdLSPServer::MessageHandler::MaxReplayCallbacks;
 460
 461 // call(), notify(), and reply() wrap the Transport, adding logging and locking.
 462 void ClangdLSPServer::callMethod(StringRef Method, llvm::json::Value Params,
 463                                  Callback<llvm::json::Value> CB) {
 464   auto ID = MsgHandler->bindReply(std::move(CB));
 465   log("--> {0}({1})", Method, ID);
 466   std::lock_guard<std::mutex> Lock(TranspWriter);
 467   Transp.call(Method, std::move(Params), ID);
 468 }
 469
 470 void ClangdLSPServer::notify(llvm::StringRef Method, llvm::json::Value Params) {
 471   log("--> {0}", Method);
 472   maybeCleanupMemory();
 473   std::lock_guard<std::mutex> Lock(TranspWriter);
 474   Transp.notify(Method, std::move(Params));
 475 }
 476
 477 static std::vector<llvm::StringRef> semanticTokenTypes() {
 478   std::vector<llvm::StringRef> Types;
 479   for (unsigned I = 0; I <= static_cast<unsigned>(HighlightingKind::LastKind);
 480        ++I)
 481     Types.push_back(toSemanticTokenType(static_cast<HighlightingKind>(I)));
 482   return Types;
 483 }
 484
 485 static std::vector<llvm::StringRef> semanticTokenModifiers() {
 486   std::vector<llvm::StringRef> Modifiers;
 487   for (unsigned I = 0;
 488        I <= static_cast<unsigned>(HighlightingModifier::LastModifier); ++I)
 489     Modifiers.push_back(
 490         toSemanticTokenModifier(static_cast<HighlightingModifier>(I)));
 491   return Modifiers;
 492 }
 493
 494 void ClangdLSPServer::onInitialize(const InitializeParams &Params,
 495                                    Callback<llvm::json::Value> Reply) {
 496   // Determine character encoding first as it affects constructed ClangdServer.
 497   if (Params.capabilities.offsetEncoding && !Opts.Encoding) {
 498     Opts.Encoding = OffsetEncoding::UTF16; // fallback
 499     for (OffsetEncoding Supported : *Params.capabilities.offsetEncoding)
 500       if (Supported != OffsetEncoding::UnsupportedEncoding) {
 501         Opts.Encoding = Supported;
 502         break;
 503       }
 504   }
 505
 506   if (Params.capabilities.TheiaSemanticHighlighting &&
 507       !Params.capabilities.SemanticTokens) {
 508     elog("Client requested legacy semanticHighlights notification, which is "
 509          "no longer supported. Migrate to standard semanticTokens request");
 510   }
 511
 512   if (Params.rootUri && *Params.rootUri)
 513     Opts.WorkspaceRoot = std::string(Params.rootUri->file());
 514   else if (Params.rootPath && !Params.rootPath->empty())
 515     Opts.WorkspaceRoot = *Params.rootPath;
 516   if (Server)
 517     return Reply(llvm::make_error<LSPError>("server already initialized",
 518                                             ErrorCode::InvalidRequest));
 519
 520   Opts.CodeComplete.EnableSnippets = Params.capabilities.CompletionSnippets;
 521   Opts.CodeComplete.IncludeFixIts = Params.capabilities.CompletionFixes;
 522   if (!Opts.CodeComplete.BundleOverloads)
 523     Opts.CodeComplete.BundleOverloads = Params.capabilities.HasSignatureHelp;
 524   Opts.CodeComplete.DocumentationFormat =
 525       Params.capabilities.CompletionDocumentationFormat;
 526   Opts.SignatureHelpDocumentationFormat =
 527       Params.capabilities.SignatureHelpDocumentationFormat;
 528   DiagOpts.EmbedFixesInDiagnostics = Params.capabilities.DiagnosticFixes;
 529   DiagOpts.SendDiagnosticCategory = Params.capabilities.DiagnosticCategory;
 530   DiagOpts.EmitRelatedLocations =
 531       Params.capabilities.DiagnosticRelatedInformation;
 532   if (Params.capabilities.WorkspaceSymbolKinds)
 533     SupportedSymbolKinds |= *Params.capabilities.WorkspaceSymbolKinds;
 534   if (Params.capabilities.CompletionItemKinds)
 535     SupportedCompletionItemKinds |= *Params.capabilities.CompletionItemKinds;
 536   SupportsCompletionLabelDetails = Params.capabilities.CompletionLabelDetail;
 537   SupportsCodeAction = Params.capabilities.CodeActionStructure;
 538   SupportsHierarchicalDocumentSymbol =
 539       Params.capabilities.HierarchicalDocumentSymbol;
 540   SupportsReferenceContainer = Params.capabilities.ReferenceContainer;
 541   SupportFileStatus = Params.initializationOptions.FileStatus;
 542   SupportsDocumentChanges = Params.capabilities.DocumentChanges;
 543   SupportsChangeAnnotation = Params.capabilities.ChangeAnnotation;
 544   HoverContentFormat = Params.capabilities.HoverContentFormat;
 545   Opts.LineFoldingOnly = Params.capabilities.LineFoldingOnly;
 546   SupportsOffsetsInSignatureHelp = Params.capabilities.OffsetsInSignatureHelp;
 547   if (Params.capabilities.WorkDoneProgress)
 548     BackgroundIndexProgressState = BackgroundIndexProgress::Empty;
 549   BackgroundIndexSkipCreate = Params.capabilities.ImplicitProgressCreation;
 550   Opts.ImplicitCancellation = !Params.capabilities.CancelsStaleRequests;
 551   Opts.PublishInactiveRegions = Params.capabilities.InactiveRegions;
 552
 553   if (Opts.UseDirBasedCDB) {
 554     DirectoryBasedGlobalCompilationDatabase::Options CDBOpts(TFS);
 555     if (const auto &Dir = Params.initializationOptions.compilationDatabasePath)
 556       CDBOpts.CompileCommandsDir = Dir;
 557     CDBOpts.ContextProvider = Opts.ContextProvider;
 558     BaseCDB =
 559         std::make_unique<DirectoryBasedGlobalCompilationDatabase>(CDBOpts);
 560   }
 561   auto Mangler = CommandMangler::detect();
 562   Mangler.SystemIncludeExtractor =
 563       getSystemIncludeExtractor(llvm::ArrayRef(Opts.QueryDriverGlobs));
 564   if (Opts.ResourceDir)
 565     Mangler.ResourceDir = *Opts.ResourceDir;
 566   CDB.emplace(BaseCDB.get(), Params.initializationOptions.fallbackFlags,
 567               std::move(Mangler));
 568
 569   if (Opts.EnableExperimentalModulesSupport) {
 570     ModulesManager.emplace(*CDB);
 571     Opts.ModulesManager = &*ModulesManager;
 572   }
 573
 574   {
 575     // Switch caller's context with LSPServer's background context. Since we
 576     // rather want to propagate information from LSPServer's context into the
 577     // Server, CDB, etc.
 578     WithContext MainContext(BackgroundContext.clone());
 579     std::optional<WithContextValue> WithOffsetEncoding;
 580     if (Opts.Encoding)
 581       WithOffsetEncoding.emplace(kCurrentOffsetEncoding, *Opts.Encoding);
 582     Server.emplace(*CDB, TFS, Opts,
 583                    static_cast<ClangdServer::Callbacks *>(this));
 584   }
 585
 586   llvm::json::Object ServerCaps{
 587       {"textDocumentSync",
 588        llvm::json::Object{
 589            {"openClose", true},
 590            {"change", (int)TextDocumentSyncKind::Incremental},
 591            {"save", true},
 592        }},
 593       {"documentFormattingProvider", true},
 594       {"documentRangeFormattingProvider", true},
 595       {"documentOnTypeFormattingProvider",
 596        llvm::json::Object{
 597            {"firstTriggerCharacter", "\n"},
 598            {"moreTriggerCharacter", {}},
 599        }},
 600       {"completionProvider",
 601        llvm::json::Object{
 602            // We don't set `(` etc as allCommitCharacters as they interact
 603            // poorly with snippet results.
 604            // See https://github.com/clangd/vscode-clangd/issues/357
 605            // Hopefully we can use them one day without this side-effect:
 606            //     https://github.com/microsoft/vscode/issues/42544
 607            {"resolveProvider", false},
 608            // We do extra checks, e.g. that > is part of ->.
 609            {"triggerCharacters", {".", "<", ">", ":", "\"", "/", "*"}},
 610        }},
 611       {"semanticTokensProvider",
 612        llvm::json::Object{
 613            {"full", llvm::json::Object{{"delta", true}}},
 614            {"range", false},
 615            {"legend",
 616             llvm::json::Object{{"tokenTypes", semanticTokenTypes()},
 617                                {"tokenModifiers", semanticTokenModifiers()}}},
 618        }},
 619       {"signatureHelpProvider",
 620        llvm::json::Object{
 621            {"triggerCharacters", {"(", ")", "{", "}", "<", ">", ","}},
 622        }},
 623       {"declarationProvider", true},
 624       {"definitionProvider", true},
 625       {"implementationProvider", true},
 626       {"typeDefinitionProvider", true},
 627       {"documentHighlightProvider", true},
 628       {"documentLinkProvider",
 629        llvm::json::Object{
 630            {"resolveProvider", false},
 631        }},
 632       {"hoverProvider", true},
 633       {"selectionRangeProvider", true},
 634       {"documentSymbolProvider", true},
 635       {"workspaceSymbolProvider", true},
 636       {"referencesProvider", true},
 637       {"astProvider", true}, // clangd extension
 638       {"typeHierarchyProvider", true},
 639       // Unfortunately our extension made use of the same capability name as the
 640       // standard. Advertise this capability to tell clients that implement our
 641       // extension we really have support for the standardized one as well.
 642       {"standardTypeHierarchyProvider", true}, // clangd extension
 643       {"memoryUsageProvider", true},           // clangd extension
 644       {"compilationDatabase",                  // clangd extension
 645        llvm::json::Object{{"automaticReload", true}}},
 646       {"inactiveRegionsProvider", true}, // clangd extension
 647       {"callHierarchyProvider", true},
 648       {"clangdInlayHintsProvider", true},
 649       {"inlayHintProvider", true},
 650       {"foldingRangeProvider", true},
 651   };
 652
 653   {
 654     LSPBinder Binder(Handlers, *this);
 655     bindMethods(Binder, Params.capabilities);
 656     if (Opts.FeatureModules)
 657       for (auto &Mod : *Opts.FeatureModules)
 658         Mod.initializeLSP(Binder, Params.rawCapabilities, ServerCaps);
 659   }
 660
 661   // Per LSP, renameProvider can be either boolean or RenameOptions.
 662   // RenameOptions will be specified if the client states it supports prepare.
 663   ServerCaps["renameProvider"] =
 664       Params.capabilities.RenamePrepareSupport
 665           ? llvm::json::Object{{"prepareProvider", true}}
 666           : llvm::json::Value(true);
 667
 668   // Per LSP, codeActionProvider can be either boolean or CodeActionOptions.
 669   // CodeActionOptions is only valid if the client supports action literal
 670   // via textDocument.codeAction.codeActionLiteralSupport.
 671   ServerCaps["codeActionProvider"] =
 672       Params.capabilities.CodeActionStructure
 673           ? llvm::json::Object{{"codeActionKinds",
 674                                 {CodeAction::QUICKFIX_KIND,
 675                                  CodeAction::REFACTOR_KIND,
 676                                  CodeAction::INFO_KIND}}}
 677           : llvm::json::Value(true);
 678
 679   std::vector<llvm::StringRef> Commands;
 680   for (llvm::StringRef Command : Handlers.CommandHandlers.keys())
 681     Commands.push_back(Command);
 682   llvm::sort(Commands);
 683   ServerCaps["executeCommandProvider"] =
 684       llvm::json::Object{{"commands", Commands}};
 685
 686   llvm::json::Object Result{
 687       {{"serverInfo",
 688         llvm::json::Object{
 689             {"name", "clangd"},
 690             {"version", llvm::formatv("{0} {1} {2}", versionString(),
 691                                       featureString(), platformString())}}},
 692        {"capabilities", std::move(ServerCaps)}}};
 693   if (Opts.Encoding)
 694     Result["offsetEncoding"] = *Opts.Encoding;
 695   Reply(std::move(Result));
 696
 697   // Apply settings after we're fully initialized.
 698   // This can start background indexing and in turn trigger LSP notifications.
 699   applyConfiguration(Params.initializationOptions.ConfigSettings);
 700 }
 701
 702 void ClangdLSPServer::onInitialized(const InitializedParams &Params) {}
 703
 704 void ClangdLSPServer::onShutdown(const NoParams &,
 705                                  Callback<std::nullptr_t> Reply) {
 706   // Do essentially nothing, just say we're ready to exit.
 707   ShutdownRequestReceived = true;
 708   Reply(nullptr);
 709 }
 710
 711 // sync is a clangd extension: it blocks until all background work completes.
 712 // It blocks the calling thread, so no messages are processed until it returns!
 713 void ClangdLSPServer::onSync(const NoParams &, Callback<std::nullptr_t> Reply) {
 714   if (Server->blockUntilIdleForTest(/*TimeoutSeconds=*/60))
 715     Reply(nullptr);
 716   else
 717     Reply(error("Not idle after a minute"));
 718 }
 719
 720 void ClangdLSPServer::onDocumentDidOpen(
 721     const DidOpenTextDocumentParams &Params) {
 722   PathRef File = Params.textDocument.uri.file();
 723
 724   const std::string &Contents = Params.textDocument.text;
 725
 726   Server->addDocument(File, Contents,
 727                       encodeVersion(Params.textDocument.version),
 728                       WantDiagnostics::Yes);
 729 }
 730
 731 void ClangdLSPServer::onDocumentDidChange(
 732     const DidChangeTextDocumentParams &Params) {
 733   auto WantDiags = WantDiagnostics::Auto;
 734   if (Params.wantDiagnostics)
 735     WantDiags =
 736         *Params.wantDiagnostics ? WantDiagnostics::Yes : WantDiagnostics::No;
 737
 738   PathRef File = Params.textDocument.uri.file();
 739   auto Code = Server->getDraft(File);
 740   if (!Code) {
 741     log("Trying to incrementally change non-added document: {0}", File);
 742     return;
 743   }
 744   std::string NewCode(*Code);
 745   for (const auto &Change : Params.contentChanges) {
 746     if (auto Err = applyChange(NewCode, Change)) {
 747       // If this fails, we are most likely going to be not in sync anymore with
 748       // the client.  It is better to remove the draft and let further
 749       // operations fail rather than giving wrong results.
 750       Server->removeDocument(File);
 751       elog("Failed to update {0}: {1}", File, std::move(Err));
 752       return;
 753     }
 754   }
 755   Server->addDocument(File, NewCode, encodeVersion(Params.textDocument.version),
 756                       WantDiags, Params.forceRebuild);
 757 }
 758
 759 void ClangdLSPServer::onDocumentDidSave(
 760     const DidSaveTextDocumentParams &Params) {
 761   Server->reparseOpenFilesIfNeeded([](llvm::StringRef) { return true; });
 762 }
 763
 764 void ClangdLSPServer::onFileEvent(const DidChangeWatchedFilesParams &Params) {
 765   // We could also reparse all open files here. However:
 766   //  - this could be frequent, and revalidating all the preambles isn't free
 767   //  - this is useful e.g. when switching git branches, but we're likely to see
 768   //    fresh headers but still have the old-branch main-file content
 769   Server->onFileEvent(Params);
 770   // FIXME: observe config files, immediately expire time-based caches, reparse:
 771   //  - compile_commands.json and compile_flags.txt
 772   //  - .clang_format and .clang-tidy
 773   //  - .clangd and clangd/config.yaml
 774 }
 775
 776 void ClangdLSPServer::onCommand(const ExecuteCommandParams &Params,
 777                                 Callback<llvm::json::Value> Reply) {
 778   auto It = Handlers.CommandHandlers.find(Params.command);
 779   if (It == Handlers.CommandHandlers.end()) {
 780     return Reply(llvm::make_error<LSPError>(
 781         llvm::formatv("Unsupported command \"{0}\".", Params.command).str(),
 782         ErrorCode::InvalidParams));
 783   }
 784   It->second(Params.argument, std::move(Reply));
 785 }
 786
 787 void ClangdLSPServer::onCommandApplyEdit(const WorkspaceEdit &WE,
 788                                          Callback<llvm::json::Value> Reply) {
 789   // The flow for "apply-fix" :
 790   // 1. We publish a diagnostic, including fixits
 791   // 2. The user clicks on the diagnostic, the editor asks us for code actions
 792   // 3. We send code actions, with the fixit embedded as context
 793   // 4. The user selects the fixit, the editor asks us to apply it
 794   // 5. We unwrap the changes and send them back to the editor
 795   // 6. The editor applies the changes (applyEdit), and sends us a reply
 796   // 7. We unwrap the reply and send a reply to the editor.
 797   applyEdit(WE, "Fix applied.", std::move(Reply));
 798 }
 799
 800 void ClangdLSPServer::onCommandApplyTweak(const TweakArgs &Args,
 801                                           Callback<llvm::json::Value> Reply) {
 802   auto Action = [this, Reply = std::move(Reply)](
 803                     llvm::Expected<Tweak::Effect> R) mutable {
 804     if (!R)
 805       return Reply(R.takeError());
 806
 807     assert(R->ShowMessage || (!R->ApplyEdits.empty() && "tweak has no effect"));
 808
 809     if (R->ShowMessage) {
 810       ShowMessageParams Msg;
 811       Msg.message = *R->ShowMessage;
 812       Msg.type = MessageType::Info;
 813       ShowMessage(Msg);
 814     }
 815     // When no edit is specified, make sure we Reply().
 816     if (R->ApplyEdits.empty())
 817       return Reply("Tweak applied.");
 818
 819     if (auto Err = validateEdits(*Server, R->ApplyEdits))
 820       return Reply(std::move(Err));
 821
 822     WorkspaceEdit WE;
 823     // FIXME: use documentChanges when SupportDocumentChanges is true.
 824     WE.changes.emplace();
 825     for (const auto &It : R->ApplyEdits) {
 826       (*WE.changes)[URI::createFile(It.first()).toString()] =
 827           It.second.asTextEdits();
 828     }
 829     // ApplyEdit will take care of calling Reply().
 830     return applyEdit(std::move(WE), "Tweak applied.", std::move(Reply));
 831   };
 832   Server->applyTweak(Args.file.file(), Args.selection, Args.tweakID,
 833                      std::move(Action));
 834 }
 835
 836 void ClangdLSPServer::onCommandApplyRename(const RenameParams &R,
 837                                            Callback<llvm::json::Value> Reply) {
 838   onRename(R, [this, Reply = std::move(Reply)](
 839                   llvm::Expected<WorkspaceEdit> Edit) mutable {
 840     if (!Edit)
 841       Reply(Edit.takeError());
 842     applyEdit(std::move(*Edit), "Rename applied.", std::move(Reply));
 843   });
 844 }
 845
 846 void ClangdLSPServer::applyEdit(WorkspaceEdit WE, llvm::json::Value Success,
 847                                 Callback<llvm::json::Value> Reply) {
 848   ApplyWorkspaceEditParams Edit;
 849   Edit.edit = std::move(WE);
 850   ApplyWorkspaceEdit(
 851       Edit, [Reply = std::move(Reply), SuccessMessage = std::move(Success)](
 852                 llvm::Expected<ApplyWorkspaceEditResponse> Response) mutable {
 853         if (!Response)
 854           return Reply(Response.takeError());
 855         if (!Response->applied) {
 856           std::string Reason = Response->failureReason
 857                                    ? *Response->failureReason
 858                                    : "unknown reason";
 859           return Reply(error("edits were not applied: {0}", Reason));
 860         }
 861         return Reply(SuccessMessage);
 862       });
 863 }
 864
 865 void ClangdLSPServer::onWorkspaceSymbol(
 866     const WorkspaceSymbolParams &Params,
 867     Callback<std::vector<SymbolInformation>> Reply) {
 868   Server->workspaceSymbols(
 869       Params.query, Params.limit.value_or(Opts.CodeComplete.Limit),
 870       [Reply = std::move(Reply),
 871        this](llvm::Expected<std::vector<SymbolInformation>> Items) mutable {
 872         if (!Items)
 873           return Reply(Items.takeError());
 874         for (auto &Sym : *Items)
 875           Sym.kind = adjustKindToCapability(Sym.kind, SupportedSymbolKinds);
 876
 877         Reply(std::move(*Items));
 878       });
 879 }
 880
 881 void ClangdLSPServer::onPrepareRename(const TextDocumentPositionParams &Params,
 882                                       Callback<PrepareRenameResult> Reply) {
 883   Server->prepareRename(
 884       Params.textDocument.uri.file(), Params.position, /*NewName*/ std::nullopt,
 885       Opts.Rename,
 886       [Reply = std::move(Reply)](llvm::Expected<RenameResult> Result) mutable {
 887         if (!Result)
 888           return Reply(Result.takeError());
 889         PrepareRenameResult PrepareResult;
 890         PrepareResult.range = Result->Target;
 891         PrepareResult.placeholder = Result->Placeholder;
 892         return Reply(std::move(PrepareResult));
 893       });
 894 }
 895
 896 void ClangdLSPServer::onRename(const RenameParams &Params,
 897                                Callback<WorkspaceEdit> Reply) {
 898   Path File = std::string(Params.textDocument.uri.file());
 899   if (!Server->getDraft(File))
 900     return Reply(llvm::make_error<LSPError>(
 901         "onRename called for non-added file", ErrorCode::InvalidParams));
 902   Server->rename(File, Params.position, Params.newName, Opts.Rename,
 903                  [File, Params, Reply = std::move(Reply),
 904                   this](llvm::Expected<RenameResult> R) mutable {
 905                    if (!R)
 906                      return Reply(R.takeError());
 907                    if (auto Err = validateEdits(*Server, R->GlobalChanges))
 908                      return Reply(std::move(Err));
 909                    WorkspaceEdit Result;
 910                    // FIXME: use documentChanges if SupportDocumentChanges is
 911                    // true.
 912                    Result.changes.emplace();
 913                    for (const auto &Rep : R->GlobalChanges) {
 914                      (*Result
 915                            .changes)[URI::createFile(Rep.first()).toString()] =
 916                          Rep.second.asTextEdits();
 917                    }
 918                    Reply(Result);
 919                  });
 920 }
 921
 922 void ClangdLSPServer::onDocumentDidClose(
 923     const DidCloseTextDocumentParams &Params) {
 924   PathRef File = Params.textDocument.uri.file();
 925   Server->removeDocument(File);
 926
 927   {
 928     std::lock_guard<std::mutex> Lock(DiagRefMutex);
 929     DiagRefMap.erase(File);
 930   }
 931   {
 932     std::lock_guard<std::mutex> HLock(SemanticTokensMutex);
 933     LastSemanticTokens.erase(File);
 934   }
 935   // clangd will not send updates for this file anymore, so we empty out the
 936   // list of diagnostics shown on the client (e.g. in the "Problems" pane of
 937   // VSCode). Note that this cannot race with actual diagnostics responses
 938   // because removeDocument() guarantees no diagnostic callbacks will be
 939   // executed after it returns.
 940   PublishDiagnosticsParams Notification;
 941   Notification.uri = URIForFile::canonicalize(File, /*TUPath=*/File);
 942   PublishDiagnostics(Notification);
 943 }
 944
 945 void ClangdLSPServer::onDocumentOnTypeFormatting(
 946     const DocumentOnTypeFormattingParams &Params,
 947     Callback<std::vector<TextEdit>> Reply) {
 948   auto File = Params.textDocument.uri.file();
 949   Server->formatOnType(File, Params.position, Params.ch, std::move(Reply));
 950 }
 951
 952 void ClangdLSPServer::onDocumentRangeFormatting(
 953     const DocumentRangeFormattingParams &Params,
 954     Callback<std::vector<TextEdit>> Reply) {
 955   auto File = Params.textDocument.uri.file();
 956   auto Code = Server->getDraft(File);
 957   Server->formatFile(File, Params.range,
 958                      [Code = std::move(Code), Reply = std::move(Reply)](
 959                          llvm::Expected<tooling::Replacements> Result) mutable {
 960                        if (Result)
 961                          Reply(replacementsToEdits(*Code, Result.get()));
 962                        else
 963                          Reply(Result.takeError());
 964                      });
 965 }
 966
 967 void ClangdLSPServer::onDocumentFormatting(
 968     const DocumentFormattingParams &Params,
 969     Callback<std::vector<TextEdit>> Reply) {
 970   auto File = Params.textDocument.uri.file();
 971   auto Code = Server->getDraft(File);
 972   Server->formatFile(File,
 973                      /*Rng=*/std::nullopt,
 974                      [Code = std::move(Code), Reply = std::move(Reply)](
 975                          llvm::Expected<tooling::Replacements> Result) mutable {
 976                        if (Result)
 977                          Reply(replacementsToEdits(*Code, Result.get()));
 978                        else
 979                          Reply(Result.takeError());
 980                      });
 981 }
 982
 983 /// The functions constructs a flattened view of the DocumentSymbol hierarchy.
 984 /// Used by the clients that do not support the hierarchical view.
 985 static std::vector<SymbolInformation>
 986 flattenSymbolHierarchy(llvm::ArrayRef<DocumentSymbol> Symbols,
 987                        const URIForFile &FileURI) {
 988   std::vector<SymbolInformation> Results;
 989   std::function<void(const DocumentSymbol &, llvm::StringRef)> Process =
 990       [&](const DocumentSymbol &S, std::optional<llvm::StringRef> ParentName) {
 991         SymbolInformation SI;
 992         SI.containerName = std::string(ParentName ? "" : *ParentName);
 993         SI.name = S.name;
 994         SI.kind = S.kind;
 995         SI.location.range = S.range;
 996         SI.location.uri = FileURI;
 997
 998         Results.push_back(std::move(SI));
 999         std::string FullName =
1000             !ParentName ? S.name : (ParentName->str() + "::" + S.name);
1001         for (auto &C : S.children)
1002           Process(C, /*ParentName=*/FullName);
1003       };
1004   for (auto &S : Symbols)
1005     Process(S, /*ParentName=*/"");
1006   return Results;
1007 }
1008
1009 void ClangdLSPServer::onDocumentSymbol(const DocumentSymbolParams &Params,
1010                                        Callback<llvm::json::Value> Reply) {
1011   URIForFile FileURI = Params.textDocument.uri;
1012   Server->documentSymbols(
1013       Params.textDocument.uri.file(),
1014       [this, FileURI, Reply = std::move(Reply)](
1015           llvm::Expected<std::vector<DocumentSymbol>> Items) mutable {
1016         if (!Items)
1017           return Reply(Items.takeError());
1018         adjustSymbolKinds(*Items, SupportedSymbolKinds);
1019         if (SupportsHierarchicalDocumentSymbol)
1020           return Reply(std::move(*Items));
1021         return Reply(flattenSymbolHierarchy(*Items, FileURI));
1022       });
1023 }
1024
1025 void ClangdLSPServer::onFoldingRange(
1026     const FoldingRangeParams &Params,
1027     Callback<std::vector<FoldingRange>> Reply) {
1028   Server->foldingRanges(Params.textDocument.uri.file(), std::move(Reply));
1029 }
1030
1031 static std::optional<Command> asCommand(const CodeAction &Action) {
1032   Command Cmd;
1033   if (Action.command && Action.edit)
1034     return std::nullopt; // Not representable. (We never emit these anyway).
1035   if (Action.command) {
1036     Cmd = *Action.command;
1037   } else if (Action.edit) {
1038     Cmd.command = std::string(ApplyFixCommand);
1039     Cmd.argument = *Action.edit;
1040   } else {
1041     return std::nullopt;
1042   }
1043   Cmd.title = Action.title;
1044   if (Action.kind && *Action.kind == CodeAction::QUICKFIX_KIND)
1045     Cmd.title = "Apply fix: " + Cmd.title;
1046   return Cmd;
1047 }
1048
1049 void ClangdLSPServer::onCodeAction(const CodeActionParams &Params,
1050                                    Callback<llvm::json::Value> Reply) {
1051   URIForFile File = Params.textDocument.uri;
1052   std::map<ClangdServer::DiagRef, clangd::Diagnostic> ToLSPDiags;
1053   ClangdServer::CodeActionInputs Inputs;
1054
1055   for (const auto& LSPDiag : Params.context.diagnostics) {
1056     if (auto DiagRef = getDiagRef(File.file(), LSPDiag)) {
1057       ToLSPDiags[*DiagRef] = LSPDiag;
1058       Inputs.Diagnostics.push_back(*DiagRef);
1059     }
1060   }
1061   Inputs.File = File.file();
1062   Inputs.Selection = Params.range;
1063   Inputs.RequestedActionKinds = Params.context.only;
1064   Inputs.TweakFilter = [this](const Tweak &T) {
1065     return Opts.TweakFilter(T);
1066   };
1067   auto CB = [this,
1068              Reply = std::move(Reply),
1069              ToLSPDiags = std::move(ToLSPDiags), File,
1070              Selection = Params.range](
1071                 llvm::Expected<ClangdServer::CodeActionResult> Fixits) mutable {
1072     if (!Fixits)
1073       return Reply(Fixits.takeError());
1074     std::vector<CodeAction> CAs;
1075     auto Version = decodeVersion(Fixits->Version);
1076     for (const auto &QF : Fixits->QuickFixes) {
1077       CAs.push_back(toCodeAction(QF.F, File, Version, SupportsDocumentChanges,
1078                                  SupportsChangeAnnotation));
1079       if (auto It = ToLSPDiags.find(QF.Diag);
1080           It != ToLSPDiags.end()) {
1081         CAs.back().diagnostics = {It->second};
1082       }
1083     }
1084
1085     for (const auto &R : Fixits->Renames)
1086       CAs.push_back(toCodeAction(R, File));
1087
1088     for (const auto &TR : Fixits->TweakRefs)
1089       CAs.push_back(toCodeAction(TR, File, Selection));
1090
1091     // If there's exactly one quick-fix, call it "preferred".
1092     // We never consider refactorings etc as preferred.
1093     CodeAction *OnlyFix = nullptr;
1094     for (auto &Action : CAs) {
1095       if (Action.kind && *Action.kind == CodeAction::QUICKFIX_KIND) {
1096         if (OnlyFix) {
1097           OnlyFix = nullptr;
1098           break;
1099         }
1100         OnlyFix = &Action;
1101       }
1102     }
1103     if (OnlyFix) {
1104       OnlyFix->isPreferred = true;
1105       if (ToLSPDiags.size() == 1 &&
1106           ToLSPDiags.begin()->second.range == Selection)
1107         OnlyFix->diagnostics = {ToLSPDiags.begin()->second};
1108     }
1109
1110     if (SupportsCodeAction)
1111       return Reply(llvm::json::Array(CAs));
1112     std::vector<Command> Commands;
1113     for (const auto &Action : CAs) {
1114       if (auto Command = asCommand(Action))
1115         Commands.push_back(std::move(*Command));
1116     }
1117     return Reply(llvm::json::Array(Commands));
1118   };
1119   Server->codeAction(Inputs, std::move(CB));
1120 }
1121
1122 void ClangdLSPServer::onCompletion(const CompletionParams &Params,
1123                                    Callback<CompletionList> Reply) {
1124   if (!shouldRunCompletion(Params)) {
1125     // Clients sometimes auto-trigger completions in undesired places (e.g.
1126     // 'a >^ '), we return empty results in those cases.
1127     vlog("ignored auto-triggered completion, preceding char did not match");
1128     return Reply(CompletionList());
1129   }
1130   auto Opts = this->Opts.CodeComplete;
1131   if (Params.limit && *Params.limit >= 0)
1132     Opts.Limit = *Params.limit;
1133   Server->codeComplete(Params.textDocument.uri.file(), Params.position, Opts,
1134                        [Reply = std::move(Reply), Opts,
1135                         this](llvm::Expected<CodeCompleteResult> List) mutable {
1136                          if (!List)
1137                            return Reply(List.takeError());
1138                          CompletionList LSPList;
1139                          LSPList.isIncomplete = List->HasMore;
1140                          for (const auto &R : List->Completions) {
1141                            CompletionItem C = R.render(Opts);
1142                            C.kind = adjustKindToCapability(
1143                                C.kind, SupportedCompletionItemKinds);
1144                            if (!SupportsCompletionLabelDetails)
1145                              removeCompletionLabelDetails(C);
1146                            LSPList.items.push_back(std::move(C));
1147                          }
1148                          return Reply(std::move(LSPList));
1149                        });
1150 }
1151
1152 void ClangdLSPServer::onSignatureHelp(const TextDocumentPositionParams &Params,
1153                                       Callback<SignatureHelp> Reply) {
1154   Server->signatureHelp(Params.textDocument.uri.file(), Params.position,
1155                         Opts.SignatureHelpDocumentationFormat,
1156                         [Reply = std::move(Reply), this](
1157                             llvm::Expected<SignatureHelp> Signature) mutable {
1158                           if (!Signature)
1159                             return Reply(Signature.takeError());
1160                           if (SupportsOffsetsInSignatureHelp)
1161                             return Reply(std::move(*Signature));
1162                           // Strip out the offsets from signature help for
1163                           // clients that only support string labels.
1164                           for (auto &SigInfo : Signature->signatures) {
1165                             for (auto &Param : SigInfo.parameters)
1166                               Param.labelOffsets.reset();
1167                           }
1168                           return Reply(std::move(*Signature));
1169                         });
1170 }
1171
1172 // Go to definition has a toggle function: if def and decl are distinct, then
1173 // the first press gives you the def, the second gives you the matching def.
1174 // getToggle() returns the counterpart location that under the cursor.
1175 //
1176 // We return the toggled location alone (ignoring other symbols) to encourage
1177 // editors to "bounce" quickly between locations, without showing a menu.
1178 static Location *getToggle(const TextDocumentPositionParams &Point,
1179                            LocatedSymbol &Sym) {
1180   // Toggle only makes sense with two distinct locations.
1181   if (!Sym.Definition || *Sym.Definition == Sym.PreferredDeclaration)
1182     return nullptr;
1183   if (Sym.Definition->uri.file() == Point.textDocument.uri.file() &&
1184       Sym.Definition->range.contains(Point.position))
1185     return &Sym.PreferredDeclaration;
1186   if (Sym.PreferredDeclaration.uri.file() == Point.textDocument.uri.file() &&
1187       Sym.PreferredDeclaration.range.contains(Point.position))
1188     return &*Sym.Definition;
1189   return nullptr;
1190 }
1191
1192 void ClangdLSPServer::onGoToDefinition(const TextDocumentPositionParams &Params,
1193                                        Callback<std::vector<Location>> Reply) {
1194   Server->locateSymbolAt(
1195       Params.textDocument.uri.file(), Params.position,
1196       [Params, Reply = std::move(Reply)](
1197           llvm::Expected<std::vector<LocatedSymbol>> Symbols) mutable {
1198         if (!Symbols)
1199           return Reply(Symbols.takeError());
1200         std::vector<Location> Defs;
1201         for (auto &S : *Symbols) {
1202           if (Location *Toggle = getToggle(Params, S))
1203             return Reply(std::vector<Location>{std::move(*Toggle)});
1204           Defs.push_back(S.Definition.value_or(S.PreferredDeclaration));
1205         }
1206         Reply(std::move(Defs));
1207       });
1208 }
1209
1210 void ClangdLSPServer::onGoToDeclaration(
1211     const TextDocumentPositionParams &Params,
1212     Callback<std::vector<Location>> Reply) {
1213   Server->locateSymbolAt(
1214       Params.textDocument.uri.file(), Params.position,
1215       [Params, Reply = std::move(Reply)](
1216           llvm::Expected<std::vector<LocatedSymbol>> Symbols) mutable {
1217         if (!Symbols)
1218           return Reply(Symbols.takeError());
1219         std::vector<Location> Decls;
1220         for (auto &S : *Symbols) {
1221           if (Location *Toggle = getToggle(Params, S))
1222             return Reply(std::vector<Location>{std::move(*Toggle)});
1223           Decls.push_back(std::move(S.PreferredDeclaration));
1224         }
1225         Reply(std::move(Decls));
1226       });
1227 }
1228
1229 void ClangdLSPServer::onSwitchSourceHeader(
1230     const TextDocumentIdentifier &Params,
1231     Callback<std::optional<URIForFile>> Reply) {
1232   Server->switchSourceHeader(
1233       Params.uri.file(),
1234       [Reply = std::move(Reply),
1235        Params](llvm::Expected<std::optional<clangd::Path>> Path) mutable {
1236         if (!Path)
1237           return Reply(Path.takeError());
1238         if (*Path)
1239           return Reply(URIForFile::canonicalize(**Path, Params.uri.file()));
1240         return Reply(std::nullopt);
1241       });
1242 }
1243
1244 void ClangdLSPServer::onDocumentHighlight(
1245     const TextDocumentPositionParams &Params,
1246     Callback<std::vector<DocumentHighlight>> Reply) {
1247   Server->findDocumentHighlights(Params.textDocument.uri.file(),
1248                                  Params.position, std::move(Reply));
1249 }
1250
1251 void ClangdLSPServer::onHover(const TextDocumentPositionParams &Params,
1252                               Callback<std::optional<Hover>> Reply) {
1253   Server->findHover(Params.textDocument.uri.file(), Params.position,
1254                     [Reply = std::move(Reply),
1255                      this](llvm::Expected<std::optional<HoverInfo>> H) mutable {
1256                       if (!H)
1257                         return Reply(H.takeError());
1258                       if (!*H)
1259                         return Reply(std::nullopt);
1260
1261                       Hover R;
1262                       R.contents.kind = HoverContentFormat;
1263                       R.range = (*H)->SymRange;
1264                       switch (HoverContentFormat) {
1265                       case MarkupKind::PlainText:
1266                         R.contents.value = (*H)->present().asPlainText();
1267                         return Reply(std::move(R));
1268                       case MarkupKind::Markdown:
1269                         R.contents.value = (*H)->present().asMarkdown();
1270                         return Reply(std::move(R));
1271                       };
1272                       llvm_unreachable("unhandled MarkupKind");
1273                     });
1274 }
1275
1276 // Our extension has a different representation on the wire than the standard.
1277 // https://clangd.llvm.org/extensions#type-hierarchy
1278 llvm::json::Value serializeTHIForExtension(TypeHierarchyItem THI) {
1279   llvm::json::Object Result{{
1280       {"name", std::move(THI.name)},
1281       {"kind", static_cast<int>(THI.kind)},
1282       {"uri", std::move(THI.uri)},
1283       {"range", THI.range},
1284       {"selectionRange", THI.selectionRange},
1285       {"data", std::move(THI.data)},
1286   }};
1287   if (THI.deprecated)
1288     Result["deprecated"] = THI.deprecated;
1289   if (THI.detail)
1290     Result["detail"] = std::move(*THI.detail);
1291
1292   if (THI.parents) {
1293     llvm::json::Array Parents;
1294     for (auto &Parent : *THI.parents)
1295       Parents.emplace_back(serializeTHIForExtension(std::move(Parent)));
1296     Result["parents"] = std::move(Parents);
1297   }
1298
1299   if (THI.children) {
1300     llvm::json::Array Children;
1301     for (auto &child : *THI.children)
1302       Children.emplace_back(serializeTHIForExtension(std::move(child)));
1303     Result["children"] = std::move(Children);
1304   }
1305   return Result;
1306 }
1307
1308 void ClangdLSPServer::onTypeHierarchy(const TypeHierarchyPrepareParams &Params,
1309                                       Callback<llvm::json::Value> Reply) {
1310   auto Serialize =
1311       [Reply = std::move(Reply)](
1312           llvm::Expected<std::vector<TypeHierarchyItem>> Resp) mutable {
1313         if (!Resp) {
1314           Reply(Resp.takeError());
1315           return;
1316         }
1317         if (Resp->empty()) {
1318           Reply(nullptr);
1319           return;
1320         }
1321         Reply(serializeTHIForExtension(std::move(Resp->front())));
1322       };
1323   Server->typeHierarchy(Params.textDocument.uri.file(), Params.position,
1324                         Params.resolve, Params.direction, std::move(Serialize));
1325 }
1326
1327 void ClangdLSPServer::onResolveTypeHierarchy(
1328     const ResolveTypeHierarchyItemParams &Params,
1329     Callback<llvm::json::Value> Reply) {
1330   auto Serialize =
1331       [Reply = std::move(Reply)](
1332           llvm::Expected<std::optional<TypeHierarchyItem>> Resp) mutable {
1333         if (!Resp) {
1334           Reply(Resp.takeError());
1335           return;
1336         }
1337         if (!*Resp) {
1338           Reply(std::move(*Resp));
1339           return;
1340         }
1341         Reply(serializeTHIForExtension(std::move(**Resp)));
1342       };
1343   Server->resolveTypeHierarchy(Params.item, Params.resolve, Params.direction,
1344                                std::move(Serialize));
1345 }
1346
1347 void ClangdLSPServer::onPrepareTypeHierarchy(
1348     const TypeHierarchyPrepareParams &Params,
1349     Callback<std::vector<TypeHierarchyItem>> Reply) {
1350   Server->typeHierarchy(Params.textDocument.uri.file(), Params.position,
1351                         Params.resolve, Params.direction, std::move(Reply));
1352 }
1353
1354 void ClangdLSPServer::onSuperTypes(
1355     const ResolveTypeHierarchyItemParams &Params,
1356     Callback<std::optional<std::vector<TypeHierarchyItem>>> Reply) {
1357   Server->superTypes(Params.item, std::move(Reply));
1358 }
1359
1360 void ClangdLSPServer::onSubTypes(
1361     const ResolveTypeHierarchyItemParams &Params,
1362     Callback<std::vector<TypeHierarchyItem>> Reply) {
1363   Server->subTypes(Params.item, std::move(Reply));
1364 }
1365
1366 void ClangdLSPServer::onPrepareCallHierarchy(
1367     const CallHierarchyPrepareParams &Params,
1368     Callback<std::vector<CallHierarchyItem>> Reply) {
1369   Server->prepareCallHierarchy(Params.textDocument.uri.file(), Params.position,
1370                                std::move(Reply));
1371 }
1372
1373 void ClangdLSPServer::onCallHierarchyIncomingCalls(
1374     const CallHierarchyIncomingCallsParams &Params,
1375     Callback<std::vector<CallHierarchyIncomingCall>> Reply) {
1376   Server->incomingCalls(Params.item, std::move(Reply));
1377 }
1378
1379 void ClangdLSPServer::onClangdInlayHints(const InlayHintsParams &Params,
1380                                          Callback<llvm::json::Value> Reply) {
1381   // Our extension has a different representation on the wire than the standard.
1382   // We have a "range" property and "kind" is represented as a string, not as an
1383   // enum value.
1384   // https://clangd.llvm.org/extensions#inlay-hints
1385   auto Serialize = [Reply = std::move(Reply)](
1386                        llvm::Expected<std::vector<InlayHint>> Hints) mutable {
1387     if (!Hints) {
1388       Reply(Hints.takeError());
1389       return;
1390     }
1391     llvm::json::Array Result;
1392     Result.reserve(Hints->size());
1393     for (auto &Hint : *Hints) {
1394       Result.emplace_back(llvm::json::Object{
1395           {"kind", llvm::to_string(Hint.kind)},
1396           {"range", Hint.range},
1397           {"position", Hint.position},
1398           // Extension doesn't have paddingLeft/Right so adjust the label
1399           // accordingly.
1400           {"label",
1401            ((Hint.paddingLeft ? " " : "") + llvm::StringRef(Hint.joinLabels()) +
1402             (Hint.paddingRight ? " " : ""))
1403                .str()},
1404       });
1405     }
1406     Reply(std::move(Result));
1407   };
1408   Server->inlayHints(Params.textDocument.uri.file(), Params.range,
1409                      std::move(Serialize));
1410 }
1411
1412 void ClangdLSPServer::onInlayHint(const InlayHintsParams &Params,
1413                                   Callback<std::vector<InlayHint>> Reply) {
1414   Server->inlayHints(Params.textDocument.uri.file(), Params.range,
1415                      std::move(Reply));
1416 }
1417
1418 void ClangdLSPServer::applyConfiguration(
1419     const ConfigurationSettings &Settings) {
1420   // Per-file update to the compilation database.
1421   llvm::StringSet<> ModifiedFiles;
1422   for (auto &[File, Command] : Settings.compilationDatabaseChanges) {
1423     auto Cmd =
1424         tooling::CompileCommand(std::move(Command.workingDirectory), File,
1425                                 std::move(Command.compilationCommand),
1426                                 /*Output=*/"");
1427     if (CDB->setCompileCommand(File, std::move(Cmd))) {
1428       ModifiedFiles.insert(File);
1429     }
1430   }
1431
1432   Server->reparseOpenFilesIfNeeded(
1433       [&](llvm::StringRef File) { return ModifiedFiles.count(File) != 0; });
1434 }
1435
1436 void ClangdLSPServer::maybeExportMemoryProfile() {
1437   if (!trace::enabled() || !ShouldProfile())
1438     return;
1439
1440   static constexpr trace::Metric MemoryUsage(
1441       "memory_usage", trace::Metric::Value, "component_name");
1442   trace::Span Tracer("ProfileBrief");
1443   MemoryTree MT;
1444   profile(MT);
1445   record(MT, "clangd_lsp_server", MemoryUsage);
1446 }
1447
1448 void ClangdLSPServer::maybeCleanupMemory() {
1449   if (!Opts.MemoryCleanup || !ShouldCleanupMemory())
1450     return;
1451   Opts.MemoryCleanup();
1452 }
1453
1454 // FIXME: This function needs to be properly tested.
1455 void ClangdLSPServer::onChangeConfiguration(
1456     const DidChangeConfigurationParams &Params) {
1457   applyConfiguration(Params.settings);
1458 }
1459
1460 void ClangdLSPServer::onReference(
1461     const ReferenceParams &Params,
1462     Callback<std::vector<ReferenceLocation>> Reply) {
1463   Server->findReferences(Params.textDocument.uri.file(), Params.position,
1464                          Opts.ReferencesLimit, SupportsReferenceContainer,
1465                          [Reply = std::move(Reply),
1466                           IncludeDecl(Params.context.includeDeclaration)](
1467                              llvm::Expected<ReferencesResult> Refs) mutable {
1468                            if (!Refs)
1469                              return Reply(Refs.takeError());
1470                            // Filter out declarations if the client asked.
1471                            std::vector<ReferenceLocation> Result;
1472                            Result.reserve(Refs->References.size());
1473                            for (auto &Ref : Refs->References) {
1474                              bool IsDecl =
1475                                  Ref.Attributes & ReferencesResult::Declaration;
1476                              if (IncludeDecl || !IsDecl)
1477                                Result.push_back(std::move(Ref.Loc));
1478                            }
1479                            return Reply(std::move(Result));
1480                          });
1481 }
1482
1483 void ClangdLSPServer::onGoToType(const TextDocumentPositionParams &Params,
1484                                  Callback<std::vector<Location>> Reply) {
1485   Server->findType(
1486       Params.textDocument.uri.file(), Params.position,
1487       [Reply = std::move(Reply)](
1488           llvm::Expected<std::vector<LocatedSymbol>> Types) mutable {
1489         if (!Types)
1490           return Reply(Types.takeError());
1491         std::vector<Location> Response;
1492         for (const LocatedSymbol &Sym : *Types)
1493           Response.push_back(Sym.Definition.value_or(Sym.PreferredDeclaration));
1494         return Reply(std::move(Response));
1495       });
1496 }
1497
1498 void ClangdLSPServer::onGoToImplementation(
1499     const TextDocumentPositionParams &Params,
1500     Callback<std::vector<Location>> Reply) {
1501   Server->findImplementations(
1502       Params.textDocument.uri.file(), Params.position,
1503       [Reply = std::move(Reply)](
1504           llvm::Expected<std::vector<LocatedSymbol>> Overrides) mutable {
1505         if (!Overrides)
1506           return Reply(Overrides.takeError());
1507         std::vector<Location> Impls;
1508         for (const LocatedSymbol &Sym : *Overrides)
1509           Impls.push_back(Sym.Definition.value_or(Sym.PreferredDeclaration));
1510         return Reply(std::move(Impls));
1511       });
1512 }
1513
1514 void ClangdLSPServer::onSymbolInfo(const TextDocumentPositionParams &Params,
1515                                    Callback<std::vector<SymbolDetails>> Reply) {
1516   Server->symbolInfo(Params.textDocument.uri.file(), Params.position,
1517                      std::move(Reply));
1518 }
1519
1520 void ClangdLSPServer::onSelectionRange(
1521     const SelectionRangeParams &Params,
1522     Callback<std::vector<SelectionRange>> Reply) {
1523   Server->semanticRanges(
1524       Params.textDocument.uri.file(), Params.positions,
1525       [Reply = std::move(Reply)](
1526           llvm::Expected<std::vector<SelectionRange>> Ranges) mutable {
1527         if (!Ranges)
1528           return Reply(Ranges.takeError());
1529         return Reply(std::move(*Ranges));
1530       });
1531 }
1532
1533 void ClangdLSPServer::onDocumentLink(
1534     const DocumentLinkParams &Params,
1535     Callback<std::vector<DocumentLink>> Reply) {
1536
1537   // TODO(forster): This currently resolves all targets eagerly. This is slow,
1538   // because it blocks on the preamble/AST being built. We could respond to the
1539   // request faster by using string matching or the lexer to find the includes
1540   // and resolving the targets lazily.
1541   Server->documentLinks(
1542       Params.textDocument.uri.file(),
1543       [Reply = std::move(Reply)](
1544           llvm::Expected<std::vector<DocumentLink>> Links) mutable {
1545         if (!Links) {
1546           return Reply(Links.takeError());
1547         }
1548         return Reply(std::move(Links));
1549       });
1550 }
1551
1552 // Increment a numeric string: "" -> 1 -> 2 -> ... -> 9 -> 10 -> 11 ...
1553 static void increment(std::string &S) {
1554   for (char &C : llvm::reverse(S)) {
1555     if (C != '9') {
1556       ++C;
1557       return;
1558     }
1559     C = '0';
1560   }
1561   S.insert(S.begin(), '1');
1562 }
1563
1564 void ClangdLSPServer::onSemanticTokens(const SemanticTokensParams &Params,
1565                                        Callback<SemanticTokens> CB) {
1566   auto File = Params.textDocument.uri.file();
1567   Server->semanticHighlights(
1568       Params.textDocument.uri.file(),
1569       [this, File(File.str()), CB(std::move(CB)), Code(Server->getDraft(File))](
1570           llvm::Expected<std::vector<HighlightingToken>> HT) mutable {
1571         if (!HT)
1572           return CB(HT.takeError());
1573         SemanticTokens Result;
1574         Result.tokens = toSemanticTokens(*HT, *Code);
1575         {
1576           std::lock_guard<std::mutex> Lock(SemanticTokensMutex);
1577           auto &Last = LastSemanticTokens[File];
1578
1579           Last.tokens = Result.tokens;
1580           increment(Last.resultId);
1581           Result.resultId = Last.resultId;
1582         }
1583         CB(std::move(Result));
1584       });
1585 }
1586
1587 void ClangdLSPServer::onSemanticTokensDelta(
1588     const SemanticTokensDeltaParams &Params,
1589     Callback<SemanticTokensOrDelta> CB) {
1590   auto File = Params.textDocument.uri.file();
1591   Server->semanticHighlights(
1592       Params.textDocument.uri.file(),
1593       [this, PrevResultID(Params.previousResultId), File(File.str()),
1594        CB(std::move(CB)), Code(Server->getDraft(File))](
1595           llvm::Expected<std::vector<HighlightingToken>> HT) mutable {
1596         if (!HT)
1597           return CB(HT.takeError());
1598         std::vector<SemanticToken> Toks = toSemanticTokens(*HT, *Code);
1599
1600         SemanticTokensOrDelta Result;
1601         {
1602           std::lock_guard<std::mutex> Lock(SemanticTokensMutex);
1603           auto &Last = LastSemanticTokens[File];
1604
1605           if (PrevResultID == Last.resultId) {
1606             Result.edits = diffTokens(Last.tokens, Toks);
1607           } else {
1608             vlog("semanticTokens/full/delta: wanted edits vs {0} but last "
1609                  "result had ID {1}. Returning full token list.",
1610                  PrevResultID, Last.resultId);
1611             Result.tokens = Toks;
1612           }
1613
1614           Last.tokens = std::move(Toks);
1615           increment(Last.resultId);
1616           Result.resultId = Last.resultId;
1617         }
1618
1619         CB(std::move(Result));
1620       });
1621 }
1622
1623 void ClangdLSPServer::onMemoryUsage(const NoParams &,
1624                                     Callback<MemoryTree> Reply) {
1625   llvm::BumpPtrAllocator DetailAlloc;
1626   MemoryTree MT(&DetailAlloc);
1627   profile(MT);
1628   Reply(std::move(MT));
1629 }
1630
1631 void ClangdLSPServer::onAST(const ASTParams &Params,
1632                             Callback<std::optional<ASTNode>> CB) {
1633   Server->getAST(Params.textDocument.uri.file(), Params.range, std::move(CB));
1634 }
1635
1636 ClangdLSPServer::ClangdLSPServer(Transport &Transp, const ThreadsafeFS &TFS,
1637                                  const ClangdLSPServer::Options &Opts)
1638     : ShouldProfile(/*Period=*/std::chrono::minutes(5),
1639                     /*Delay=*/std::chrono::minutes(1)),
1640       ShouldCleanupMemory(/*Period=*/std::chrono::minutes(1),
1641                           /*Delay=*/std::chrono::minutes(1)),
1642       BackgroundContext(Context::current().clone()), Transp(Transp),
1643       MsgHandler(new MessageHandler(*this)), TFS(TFS),
1644       SupportedSymbolKinds(defaultSymbolKinds()),
1645       SupportedCompletionItemKinds(defaultCompletionItemKinds()), Opts(Opts) {
1646   if (Opts.ConfigProvider) {
1647     assert(!Opts.ContextProvider &&
1648            "Only one of ConfigProvider and ContextProvider allowed!");
1649     this->Opts.ContextProvider = ClangdServer::createConfiguredContextProvider(
1650         Opts.ConfigProvider, this);
1651   }
1652   LSPBinder Bind(this->Handlers, *this);
1653   Bind.method("initialize", this, &ClangdLSPServer::onInitialize);
1654 }
1655
1656 void ClangdLSPServer::bindMethods(LSPBinder &Bind,
1657                                   const ClientCapabilities &Caps) {
1658   // clang-format off
1659   Bind.notification("initialized", this, &ClangdLSPServer::onInitialized);
1660   Bind.method("shutdown", this, &ClangdLSPServer::onShutdown);
1661   Bind.method("sync", this, &ClangdLSPServer::onSync);
1662   Bind.method("textDocument/rangeFormatting", this, &ClangdLSPServer::onDocumentRangeFormatting);
1663   Bind.method("textDocument/onTypeFormatting", this, &ClangdLSPServer::onDocumentOnTypeFormatting);
1664   Bind.method("textDocument/formatting", this, &ClangdLSPServer::onDocumentFormatting);
1665   Bind.method("textDocument/codeAction", this, &ClangdLSPServer::onCodeAction);
1666   Bind.method("textDocument/completion", this, &ClangdLSPServer::onCompletion);
1667   Bind.method("textDocument/signatureHelp", this, &ClangdLSPServer::onSignatureHelp);
1668   Bind.method("textDocument/definition", this, &ClangdLSPServer::onGoToDefinition);
1669   Bind.method("textDocument/declaration", this, &ClangdLSPServer::onGoToDeclaration);
1670   Bind.method("textDocument/typeDefinition", this, &ClangdLSPServer::onGoToType);
1671   Bind.method("textDocument/implementation", this, &ClangdLSPServer::onGoToImplementation);
1672   Bind.method("textDocument/references", this, &ClangdLSPServer::onReference);
1673   Bind.method("textDocument/switchSourceHeader", this, &ClangdLSPServer::onSwitchSourceHeader);
1674   Bind.method("textDocument/prepareRename", this, &ClangdLSPServer::onPrepareRename);
1675   Bind.method("textDocument/rename", this, &ClangdLSPServer::onRename);
1676   Bind.method("textDocument/hover", this, &ClangdLSPServer::onHover);
1677   Bind.method("textDocument/documentSymbol", this, &ClangdLSPServer::onDocumentSymbol);
1678   Bind.method("workspace/executeCommand", this, &ClangdLSPServer::onCommand);
1679   Bind.method("textDocument/documentHighlight", this, &ClangdLSPServer::onDocumentHighlight);
1680   Bind.method("workspace/symbol", this, &ClangdLSPServer::onWorkspaceSymbol);
1681   Bind.method("textDocument/ast", this, &ClangdLSPServer::onAST);
1682   Bind.notification("textDocument/didOpen", this, &ClangdLSPServer::onDocumentDidOpen);
1683   Bind.notification("textDocument/didClose", this, &ClangdLSPServer::onDocumentDidClose);
1684   Bind.notification("textDocument/didChange", this, &ClangdLSPServer::onDocumentDidChange);
1685   Bind.notification("textDocument/didSave", this, &ClangdLSPServer::onDocumentDidSave);
1686   Bind.notification("workspace/didChangeWatchedFiles", this, &ClangdLSPServer::onFileEvent);
1687   Bind.notification("workspace/didChangeConfiguration", this, &ClangdLSPServer::onChangeConfiguration);
1688   Bind.method("textDocument/symbolInfo", this, &ClangdLSPServer::onSymbolInfo);
1689   Bind.method("textDocument/typeHierarchy", this, &ClangdLSPServer::onTypeHierarchy);
1690   Bind.method("typeHierarchy/resolve", this, &ClangdLSPServer::onResolveTypeHierarchy);
1691   Bind.method("textDocument/prepareTypeHierarchy", this, &ClangdLSPServer::onPrepareTypeHierarchy);
1692   Bind.method("typeHierarchy/supertypes", this, &ClangdLSPServer::onSuperTypes);
1693   Bind.method("typeHierarchy/subtypes", this, &ClangdLSPServer::onSubTypes);
1694   Bind.method("textDocument/prepareCallHierarchy", this, &ClangdLSPServer::onPrepareCallHierarchy);
1695   Bind.method("callHierarchy/incomingCalls", this, &ClangdLSPServer::onCallHierarchyIncomingCalls);
1696   Bind.method("textDocument/selectionRange", this, &ClangdLSPServer::onSelectionRange);
1697   Bind.method("textDocument/documentLink", this, &ClangdLSPServer::onDocumentLink);
1698   Bind.method("textDocument/semanticTokens/full", this, &ClangdLSPServer::onSemanticTokens);
1699   Bind.method("textDocument/semanticTokens/full/delta", this, &ClangdLSPServer::onSemanticTokensDelta);
1700   Bind.method("clangd/inlayHints", this, &ClangdLSPServer::onClangdInlayHints);
1701   Bind.method("textDocument/inlayHint", this, &ClangdLSPServer::onInlayHint);
1702   Bind.method("$/memoryUsage", this, &ClangdLSPServer::onMemoryUsage);
1703   Bind.method("textDocument/foldingRange", this, &ClangdLSPServer::onFoldingRange);
1704   Bind.command(ApplyFixCommand, this, &ClangdLSPServer::onCommandApplyEdit);
1705   Bind.command(ApplyTweakCommand, this, &ClangdLSPServer::onCommandApplyTweak);
1706   Bind.command(ApplyRenameCommand, this, &ClangdLSPServer::onCommandApplyRename);
1707
1708   ApplyWorkspaceEdit = Bind.outgoingMethod("workspace/applyEdit");
1709   PublishDiagnostics = Bind.outgoingNotification("textDocument/publishDiagnostics");
1710   if (Caps.InactiveRegions)
1711     PublishInactiveRegions = Bind.outgoingNotification("textDocument/inactiveRegions");
1712   ShowMessage = Bind.outgoingNotification("window/showMessage");
1713   NotifyFileStatus = Bind.outgoingNotification("textDocument/clangd.fileStatus");
1714   CreateWorkDoneProgress = Bind.outgoingMethod("window/workDoneProgress/create");
1715   BeginWorkDoneProgress = Bind.outgoingNotification("$/progress");
1716   ReportWorkDoneProgress = Bind.outgoingNotification("$/progress");
1717   EndWorkDoneProgress = Bind.outgoingNotification("$/progress");
1718   if(Caps.SemanticTokenRefreshSupport)
1719     SemanticTokensRefresh = Bind.outgoingMethod("workspace/semanticTokens/refresh");
1720   // clang-format on
1721 }
1722
1723 ClangdLSPServer::~ClangdLSPServer() {
1724   IsBeingDestroyed = true;
1725   // Explicitly destroy ClangdServer first, blocking on threads it owns.
1726   // This ensures they don't access any other members.
1727   Server.reset();
1728 }
1729
1730 bool ClangdLSPServer::run() {
1731   // Run the Language Server loop.
1732   bool CleanExit = true;
1733   if (auto Err = Transp.loop(*MsgHandler)) {
1734     elog("Transport error: {0}", std::move(Err));
1735     CleanExit = false;
1736   }
1737
1738   return CleanExit && ShutdownRequestReceived;
1739 }
1740
1741 void ClangdLSPServer::profile(MemoryTree &MT) const {
1742   if (Server)
1743     Server->profile(MT.child("clangd_server"));
1744 }
1745
1746 std::optional<ClangdServer::DiagRef>
1747 ClangdLSPServer::getDiagRef(StringRef File, const clangd::Diagnostic &D) {
1748   std::lock_guard<std::mutex> Lock(DiagRefMutex);
1749   auto DiagToDiagRefIter = DiagRefMap.find(File);
1750   if (DiagToDiagRefIter == DiagRefMap.end())
1751     return std::nullopt;
1752
1753   const auto &DiagToDiagRefMap = DiagToDiagRefIter->second;
1754   auto FixItsIter = DiagToDiagRefMap.find(toDiagKey(D));
1755   if (FixItsIter == DiagToDiagRefMap.end())
1756     return std::nullopt;
1757
1758   return FixItsIter->second;
1759 }
1760
1761 // A completion request is sent when the user types '>' or ':', but we only
1762 // want to trigger on '->' and '::'. We check the preceding text to make
1763 // sure it matches what we expected.
1764 // Running the lexer here would be more robust (e.g. we can detect comments
1765 // and avoid triggering completion there), but we choose to err on the side
1766 // of simplicity here.
1767 bool ClangdLSPServer::shouldRunCompletion(
1768     const CompletionParams &Params) const {
1769   if (Params.context.triggerKind != CompletionTriggerKind::TriggerCharacter)
1770     return true;
1771   auto Code = Server->getDraft(Params.textDocument.uri.file());
1772   if (!Code)
1773     return true; // completion code will log the error for untracked doc.
1774   auto Offset = positionToOffset(*Code, Params.position,
1775                                  /*AllowColumnsBeyondLineLength=*/false);
1776   if (!Offset) {
1777     vlog("could not convert position '{0}' to offset for file '{1}'",
1778          Params.position, Params.textDocument.uri.file());
1779     return true;
1780   }
1781   return allowImplicitCompletion(*Code, *Offset);
1782 }
1783
1784 void ClangdLSPServer::onDiagnosticsReady(PathRef File, llvm::StringRef Version,
1785                                          llvm::ArrayRef<Diag> Diagnostics) {
1786   PublishDiagnosticsParams Notification;
1787   Notification.version = decodeVersion(Version);
1788   Notification.uri = URIForFile::canonicalize(File, /*TUPath=*/File);
1789   DiagnosticToDiagRefMap LocalDiagMap; // Temporary storage
1790   for (auto &Diag : Diagnostics) {
1791     toLSPDiags(Diag, Notification.uri, DiagOpts,
1792                [&](clangd::Diagnostic LSPDiag, llvm::ArrayRef<Fix> Fixes) {
1793                  if (DiagOpts.EmbedFixesInDiagnostics) {
1794                    std::vector<CodeAction> CodeActions;
1795                    for (const auto &Fix : Fixes)
1796                      CodeActions.push_back(toCodeAction(
1797                          Fix, Notification.uri, Notification.version,
1798                          SupportsDocumentChanges, SupportsChangeAnnotation));
1799                    LSPDiag.codeActions.emplace(std::move(CodeActions));
1800                    if (LSPDiag.codeActions->size() == 1)
1801                      LSPDiag.codeActions->front().isPreferred = true;
1802                  }
1803                  LocalDiagMap[toDiagKey(LSPDiag)] = {Diag.Range, Diag.Message};
1804                  Notification.diagnostics.push_back(std::move(LSPDiag));
1805                });
1806   }
1807
1808   // Cache DiagRefMap
1809   {
1810     std::lock_guard<std::mutex> Lock(DiagRefMutex);
1811     DiagRefMap[File] = LocalDiagMap;
1812   }
1813
1814   // Send a notification to the LSP client.
1815   PublishDiagnostics(Notification);
1816 }
1817
1818 void ClangdLSPServer::onInactiveRegionsReady(
1819     PathRef File, std::vector<Range> InactiveRegions) {
1820   InactiveRegionsParams Notification;
1821   Notification.TextDocument = {URIForFile::canonicalize(File, /*TUPath=*/File)};
1822   Notification.InactiveRegions = std::move(InactiveRegions);
1823
1824   PublishInactiveRegions(Notification);
1825 }
1826
1827 void ClangdLSPServer::onBackgroundIndexProgress(
1828     const BackgroundQueue::Stats &Stats) {
1829   static const char ProgressToken[] = "backgroundIndexProgress";
1830
1831   // The background index did some work, maybe we need to cleanup
1832   maybeCleanupMemory();
1833
1834   std::lock_guard<std::mutex> Lock(BackgroundIndexProgressMutex);
1835
1836   auto NotifyProgress = [this](const BackgroundQueue::Stats &Stats) {
1837     if (BackgroundIndexProgressState != BackgroundIndexProgress::Live) {
1838       WorkDoneProgressBegin Begin;
1839       Begin.percentage = true;
1840       Begin.title = "indexing";
1841       BeginWorkDoneProgress({ProgressToken, std::move(Begin)});
1842       BackgroundIndexProgressState = BackgroundIndexProgress::Live;
1843     }
1844
1845     if (Stats.Completed < Stats.Enqueued) {
1846       assert(Stats.Enqueued > Stats.LastIdle);
1847       WorkDoneProgressReport Report;
1848       Report.percentage = 100 * (Stats.Completed - Stats.LastIdle) /
1849                           (Stats.Enqueued - Stats.LastIdle);
1850       Report.message =
1851           llvm::formatv("{0}/{1}", Stats.Completed - Stats.LastIdle,
1852                         Stats.Enqueued - Stats.LastIdle);
1853       ReportWorkDoneProgress({ProgressToken, std::move(Report)});
1854     } else {
1855       assert(Stats.Completed == Stats.Enqueued);
1856       EndWorkDoneProgress({ProgressToken, WorkDoneProgressEnd()});
1857       BackgroundIndexProgressState = BackgroundIndexProgress::Empty;
1858     }
1859   };
1860
1861   switch (BackgroundIndexProgressState) {
1862   case BackgroundIndexProgress::Unsupported:
1863     return;
1864   case BackgroundIndexProgress::Creating:
1865     // Cache this update for when the progress bar is available.
1866     PendingBackgroundIndexProgress = Stats;
1867     return;
1868   case BackgroundIndexProgress::Empty: {
1869     if (BackgroundIndexSkipCreate) {
1870       NotifyProgress(Stats);
1871       break;
1872     }
1873     // Cache this update for when the progress bar is available.
1874     PendingBackgroundIndexProgress = Stats;
1875     BackgroundIndexProgressState = BackgroundIndexProgress::Creating;
1876     WorkDoneProgressCreateParams CreateRequest;
1877     CreateRequest.token = ProgressToken;
1878     CreateWorkDoneProgress(
1879         CreateRequest,
1880         [this, NotifyProgress](llvm::Expected<std::nullptr_t> E) {
1881           std::lock_guard<std::mutex> Lock(BackgroundIndexProgressMutex);
1882           if (E) {
1883             NotifyProgress(this->PendingBackgroundIndexProgress);
1884           } else {
1885             elog("Failed to create background index progress bar: {0}",
1886                  E.takeError());
1887             // give up forever rather than thrashing about
1888             BackgroundIndexProgressState = BackgroundIndexProgress::Unsupported;
1889           }
1890         });
1891     break;
1892   }
1893   case BackgroundIndexProgress::Live:
1894     NotifyProgress(Stats);
1895     break;
1896   }
1897 }
1898
1899 void ClangdLSPServer::onFileUpdated(PathRef File, const TUStatus &Status) {
1900   if (!SupportFileStatus)
1901     return;
1902   // FIXME: we don't emit "BuildingFile" and `RunningAction`, as these
1903   // two statuses are running faster in practice, which leads the UI constantly
1904   // changing, and doesn't provide much value. We may want to emit status at a
1905   // reasonable time interval (e.g. 0.5s).
1906   if (Status.PreambleActivity == PreambleAction::Idle &&
1907       (Status.ASTActivity.K == ASTAction::Building ||
1908        Status.ASTActivity.K == ASTAction::RunningAction))
1909     return;
1910   NotifyFileStatus(Status.render(File));
1911 }
1912
1913 void ClangdLSPServer::onSemanticsMaybeChanged(PathRef File) {
1914   if (SemanticTokensRefresh) {
1915     SemanticTokensRefresh(NoParams{}, [](llvm::Expected<std::nullptr_t> E) {
1916       if (E)
1917         return;
1918       elog("Failed to refresh semantic tokens: {0}", E.takeError());
1919     });
1920   }
1921 }
1922
1923 } // namespace clangd
1924 } // namespace clang