Backport recent update of completion

src/clang_complete.cc

@@ -270,7 +270,8 @@ void BuildDetailString(CXCompletionString completion_string,
                        bool& do_insert,
                        lsInsertTextFormat& format,
                        std::vector<std::string>* parameters,
-                       bool include_snippets) {
+                       bool include_snippets,
+                       int& angle_stack) {
   int num_chunks = clang_getNumCompletionChunks(completion_string);
   auto append = [&](const char* text) {
     detail += text;
@@ -285,8 +286,11 @@ void BuildDetailString(CXCompletionString completion_string,
       case CXCompletionChunk_Optional: {
         CXCompletionString nested =
             clang_getCompletionChunkCompletionString(completion_string, i);
-        BuildDetailString(nested, label, detail, insert, do_insert, format,
+        // Do not add text to insert string if we're in angle brackets.
-                          parameters, include_snippets);
+        bool should_insert = do_insert && angle_stack == 0;
+        BuildDetailString(nested, label, detail, insert,
+                          should_insert, format, parameters,
+                          include_snippets, angle_stack);
         break;
       }
 
@@ -348,8 +352,8 @@ void BuildDetailString(CXCompletionString completion_string,
       case CXCompletionChunk_RightBracket: append("]"); break;
       case CXCompletionChunk_LeftBrace: append("{"); break;
       case CXCompletionChunk_RightBrace: append("}"); break;
-      case CXCompletionChunk_LeftAngle: append("<"); break;
+      case CXCompletionChunk_LeftAngle: append("<"); angle_stack++; break;
-      case CXCompletionChunk_RightAngle: append(">"); break;
+      case CXCompletionChunk_RightAngle: append(">"); angle_stack--; break;
       case CXCompletionChunk_Comma: append(", "); break;
       case CXCompletionChunk_Colon: append(":"); break;
       case CXCompletionChunk_SemiColon: append(";"); break;
@@ -366,7 +370,8 @@ void BuildDetailString(CXCompletionString completion_string,
 void TryEnsureDocumentParsed(ClangCompleteManager* manager,
                              std::shared_ptr<CompletionSession> session,
                              std::unique_ptr<ClangTranslationUnit>* tu,
-                             ClangIndex* index) {
+                             ClangIndex* index,
+                             bool emit_diag) {
   // Nothing to do. We already have a translation unit.
   if (*tu)
     return;
@@ -414,11 +419,10 @@ void TryEnsureDocumentParsed(ClangCompleteManager* manager,
   }
 }
 
-void CompletionParseMain(ClangCompleteManager* completion_manager) {
+void CompletionPreloadMain(ClangCompleteManager* completion_manager) {
   while (true) {
     // Fetching the completion request blocks until we have a request.
-    ClangCompleteManager::ParseRequest request =
+    auto request = completion_manager->preload_requests_.Dequeue();
-        completion_manager->parse_requests_.Dequeue();
 
     // If we don't get a session then that means we don't care about the file
     // anymore - abandon the request.
@@ -429,23 +433,23 @@ void CompletionParseMain(ClangCompleteManager* completion_manager) {
     if (!session)
       continue;
 
+    // Note: we only preload completion. We emit diagnostics for the
+    // completion preload though.
+    CompletionSession::Tu* tu = &session->completion;
+
     // If we've parsed it more recently than the request time, don't bother
     // reparsing.
-    if (session->tu_last_parsed_at &&
+    if (tu->last_parsed_at && *tu->last_parsed_at > request.request_time)
-        *session->tu_last_parsed_at > request.request_time) {
       continue;
-    }
 
     std::unique_ptr<ClangTranslationUnit> parsing;
-    TryEnsureDocumentParsed(completion_manager, session, &parsing,
+    TryEnsureDocumentParsed(completion_manager, session, &parsing, &tu->index,
-                            &session->index);
+                            true);
 
     // Activate new translation unit.
-    // tu_last_parsed_at is only read by this thread, so it doesn't need to be
+    std::lock_guard<std::mutex> lock(tu->lock);
-    // under the mutex.
+    tu->last_parsed_at = std::chrono::high_resolution_clock::now();
-    session->tu_last_parsed_at = std::chrono::high_resolution_clock::now();
+    tu->tu = std::move(parsing);
-    std::lock_guard<std::mutex> lock(session->tu_lock);
-    session->tu = std::move(parsing);
   }
 }
 
@@ -468,15 +472,15 @@ void CompletionQueryMain(ClangCompleteManager* completion_manager) {
         completion_manager->TryGetSession(path, true /*mark_as_completion*/,
                                           true /*create_if_needed*/);
 
-    std::lock_guard<std::mutex> lock(session->tu_lock);
+    std::lock_guard<std::mutex> lock(session->completion.lock);
     Timer timer;
-    TryEnsureDocumentParsed(completion_manager, session, &session->tu,
+    TryEnsureDocumentParsed(completion_manager, session, &session->completion.tu,
-                            &session->index);
+                            &session->completion.index, false);
     timer.ResetAndPrint("[complete] TryEnsureDocumentParsed");
 
     // It is possible we failed to create the document despite
     // |TryEnsureDocumentParsed|.
-    if (!session->tu)
+    if (!session->completion.tu)
       continue;
 
     timer.Reset();
@@ -485,185 +489,161 @@ void CompletionQueryMain(ClangCompleteManager* completion_manager) {
     std::vector<CXUnsavedFile> unsaved = snapshot.AsUnsavedFiles();
     timer.ResetAndPrint("[complete] Creating WorkingFile snapshot");
 
-    // Emit code completion data.
+    unsigned const kCompleteOptions =
-    if (request->position) {
+        CXCodeComplete_IncludeMacros | CXCodeComplete_IncludeBriefComments;
-      // Language server is 0-based, clang is 1-based.
+    CXCodeCompleteResults* cx_results = clang_codeCompleteAt(
-      unsigned line = request->position->line + 1;
+        session->completion.tu->cx_tu, session->file.filename.c_str(),
-      unsigned column = request->position->character + 1;
+        request->position.line + 1, request->position.character + 1,
+        unsaved.data(), (unsigned)unsaved.size(), kCompleteOptions);
+    timer.ResetAndPrint("[complete] clangCodeCompleteAt");
+    if (!cx_results) {
+      request->on_complete({}, false /*is_cached_result*/);
+      continue;
+    }
 
-      timer.Reset();
+    std::vector<lsCompletionItem> ls_result;
-      unsigned const kCompleteOptions =
+    // this is a guess but can be larger in case of std::optional
-          CXCodeComplete_IncludeMacros | CXCodeComplete_IncludeBriefComments;
+    // parameters, as they may be expanded into multiple items
-      CXCodeCompleteResults* cx_results = clang_codeCompleteAt(
+    ls_result.reserve(cx_results->NumResults);
-          session->tu->cx_tu, session->file.filename.c_str(), line, column,
+
-          unsaved.data(), (unsigned)unsaved.size(), kCompleteOptions);
+    timer.Reset();
-      timer.ResetAndPrint("[complete] clangCodeCompleteAt");
+    for (unsigned i = 0; i < cx_results->NumResults; ++i) {
-      if (!cx_results) {
+      CXCompletionResult& result = cx_results->Results[i];
-        if (request->on_complete)
+
-          request->on_complete({}, false /*is_cached_result*/);
+      // TODO: Try to figure out how we can hide base method calls without
+      // also hiding method implementation assistance, ie,
+      //
+      //    void Foo::* {
+      //    }
+      //
+
+      if (clang_getCompletionAvailability(result.CompletionString) ==
+          CXAvailability_NotAvailable)
         continue;
-      }
 
-      {
+      // TODO: fill in more data
-        if (request->on_complete) {
+      lsCompletionItem ls_completion_item;
-          std::vector<lsCompletionItem> ls_result;
-          // this is a guess but can be larger in case of std::optional parameters,
-          // as they may be expanded into multiple items
-          ls_result.reserve(cx_results->NumResults);
 
-          timer.Reset();
+      ls_completion_item.kind = GetCompletionKind(result.CursorKind);
-          for (unsigned i = 0; i < cx_results->NumResults; ++i) {
+      ls_completion_item.documentation =
-            CXCompletionResult& result = cx_results->Results[i];
+          ToString(clang_getCompletionBriefComment(result.CompletionString));
 
-            // TODO: Try to figure out how we can hide base method calls without
+      // label/detail/filterText/insertText/priority
-            // also hiding method implementation assistance, ie,
+      if (g_config->completion.detailedLabel) {
-            //
+        ls_completion_item.detail = ToString(
-            //    void Foo::* {
+            clang_getCompletionParent(result.CompletionString, nullptr));
-            //    }
-            //
 
-            if (clang_getCompletionAvailability(result.CompletionString) ==
+        auto first_idx = ls_result.size();
-                CXAvailability_NotAvailable)
+        ls_result.push_back(ls_completion_item);
-              continue;
 
-            // TODO: fill in more data
+        // label/filterText/insertText
-            lsCompletionItem ls_completion_item;
+        BuildCompletionItemTexts(ls_result, result.CompletionString,
+                                 g_config->client.snippetSupport);
 
-            ls_completion_item.kind = GetCompletionKind(result.CursorKind);
+        for (auto i = first_idx; i < ls_result.size(); ++i) {
-            ls_completion_item.documentation = ToString(
+          if (g_config->client.snippetSupport &&
-                clang_getCompletionBriefComment(result.CompletionString));
+              ls_result[i].insertTextFormat == lsInsertTextFormat::Snippet) {
-
+            ls_result[i].insertText += "$0";
-            // label/detail/filterText/insertText/priority
-            if (g_config->completion.detailedLabel) {
-              ls_completion_item.detail = ToString(
-                  clang_getCompletionParent(result.CompletionString, nullptr));
-
-              auto first_idx = ls_result.size();
-              ls_result.push_back(ls_completion_item);
-
-              // label/filterText/insertText
-              BuildCompletionItemTexts(
-                  ls_result, result.CompletionString,
-                  g_config->client.snippetSupport);
-
-              for (auto i = first_idx; i < ls_result.size(); ++i) {
-                if (g_config->client.snippetSupport &&
-                    ls_result[i].insertTextFormat ==
-                        lsInsertTextFormat::Snippet) {
-                  ls_result[i].insertText += "$0";
-                }
-
-                ls_result[i].priority_ = GetCompletionPriority(
-                    result.CompletionString, result.CursorKind,
-                    ls_result[i].filterText);
-              }
-            } else {
-              bool do_insert = true;
-              BuildDetailString(
-                  result.CompletionString, ls_completion_item.label,
-                  ls_completion_item.detail, ls_completion_item.insertText,
-                  do_insert, ls_completion_item.insertTextFormat,
-                  &ls_completion_item.parameters_,
-                  g_config->client.snippetSupport);
-              if (g_config->client.snippetSupport &&
-                  ls_completion_item.insertTextFormat ==
-                      lsInsertTextFormat::Snippet) {
-                ls_completion_item.insertText += "$0";
-              }
-              ls_completion_item.priority_ = GetCompletionPriority(
-                  result.CompletionString, result.CursorKind,
-                  ls_completion_item.label);
-              ls_result.push_back(ls_completion_item);
-            }
           }
 
-          timer.ResetAndPrint("[complete] Building " +
+          ls_result[i].priority_ =
-                              std::to_string(ls_result.size()) +
+              GetCompletionPriority(result.CompletionString, result.CursorKind,
-                              " completion results");
+                                    ls_result[i].filterText);
-
-          request->on_complete(ls_result, false /*is_cached_result*/);
         }
+      } else {
+        bool do_insert = true;
+        int angle_stack = 0;
+        BuildDetailString(result.CompletionString, ls_completion_item.label,
+                          ls_completion_item.detail,
+                          ls_completion_item.insertText, do_insert,
+                          ls_completion_item.insertTextFormat,
+                          &ls_completion_item.parameters_,
+                          g_config->client.snippetSupport, angle_stack);
+        if (g_config->client.snippetSupport &&
+            ls_completion_item.insertTextFormat ==
+                lsInsertTextFormat::Snippet) {
+          ls_completion_item.insertText += "$0";
+        }
+        ls_completion_item.priority_ =
+            GetCompletionPriority(result.CompletionString, result.CursorKind,
+                                  ls_completion_item.label);
+        ls_result.push_back(ls_completion_item);
       }
-
-      // Make sure |ls_results| is destroyed before clearing |cx_results|.
-      clang_disposeCodeCompleteResults(cx_results);
     }
 
+    timer.ResetAndPrint("[complete] Building " +
+                        std::to_string(ls_result.size()) +
+                        " completion results");
+
+    request->on_complete(ls_result, false /*is_cached_result*/);
+
+    // Make sure |ls_results| is destroyed before clearing |cx_results|.
+    clang_disposeCodeCompleteResults(cx_results);
+  }
+}
+
+void DiagnosticQueryMain(ClangCompleteManager* completion_manager) {
+  while (true) {
+    // Fetching the completion request blocks until we have a request.
+    ClangCompleteManager::DiagnosticRequest request =
+        completion_manager->diagnostic_request_.Dequeue();
+    std::string path = request.document.uri.GetPath();
+
+    std::shared_ptr<CompletionSession> session =
+        completion_manager->TryGetSession(path, true /*mark_as_completion*/,
+                                          true /*create_if_needed*/);
+
+    // At this point, we must have a translation unit. Block until we have one.
+    std::lock_guard<std::mutex> lock(session->diagnostics.lock);
+    Timer timer;
+    TryEnsureDocumentParsed(
+        completion_manager, session, &session->diagnostics.tu,
+        &session->diagnostics.index, false /*emit_diagnostics*/);
+    timer.ResetAndPrint("[diagnostics] TryEnsureDocumentParsed");
+
+    // It is possible we failed to create the document despite
+    // |TryEnsureDocumentParsed|.
+    if (!session->diagnostics.tu)
+      continue;
+
+    timer.Reset();
+    WorkingFiles::Snapshot snapshot =
+        completion_manager->working_files_->AsSnapshot({StripFileType(path)});
+    std::vector<CXUnsavedFile> unsaved = snapshot.AsUnsavedFiles();
+    timer.ResetAndPrint("[diagnostics] Creating WorkingFile snapshot");
+
     // Emit diagnostics.
-    if (request->emit_diagnostics) {
+    timer.Reset();
-      // TODO: before emitting diagnostics check if we have another completion
+    session->diagnostics.tu = ClangTranslationUnit::Reparse(
-      // request and think about servicing that first, because it may be much
+        std::move(session->diagnostics.tu), unsaved);
-      // faster than reparsing the document.
+    timer.ResetAndPrint("[diagnostics] clang_reparseTranslationUnit");
-      // TODO: have a separate thread for diagnostics?
+    if (!session->diagnostics.tu) {
-
+      LOG_S(ERROR) << "Reparsing translation unit for diagnostics failed for "
-      timer.Reset();
+                   << path;
-      session->tu =
+      continue;
-          ClangTranslationUnit::Reparse(std::move(session->tu), unsaved);
-      timer.ResetAndPrint("[complete] clang_reparseTranslationUnit");
-      if (!session->tu) {
-        LOG_S(ERROR) << "Reparsing translation unit for diagnostics failed for "
-                     << path;
-        continue;
-      }
-
-      size_t num_diagnostics = clang_getNumDiagnostics(session->tu->cx_tu);
-      std::vector<lsDiagnostic> ls_diagnostics;
-      ls_diagnostics.reserve(num_diagnostics);
-      for (unsigned i = 0; i < num_diagnostics; ++i) {
-        CXDiagnostic cx_diag = clang_getDiagnostic(session->tu->cx_tu, i);
-        std::optional<lsDiagnostic> diagnostic =
-            BuildAndDisposeDiagnostic(cx_diag, path);
-        // Filter messages like "too many errors emitted, stopping now
-        // [-ferror-limit=]" which has line = 0 and got subtracted by 1 after
-        // conversion to lsDiagnostic
-        if (diagnostic && diagnostic->range.start.line >= 0)
-          ls_diagnostics.push_back(*diagnostic);
-      }
-      completion_manager->on_diagnostic_(session->file.filename,
-                                         ls_diagnostics);
-
-      /*
-      timer.Reset();
-      completion_manager->on_index_(session->tu.get(), unsaved,
-                                    session->file.filename, session->file.args);
-      timer.ResetAndPrint("[complete] Reindex file");
-      */
     }
 
-    continue;
+    size_t num_diagnostics =
+        clang_getNumDiagnostics(session->diagnostics.tu->cx_tu);
+    std::vector<lsDiagnostic> ls_diagnostics;
+    ls_diagnostics.reserve(num_diagnostics);
+    for (unsigned i = 0; i < num_diagnostics; ++i) {
+      CXDiagnostic cx_diag =
+          clang_getDiagnostic(session->diagnostics.tu->cx_tu, i);
+      std::optional<lsDiagnostic> diagnostic =
+          BuildAndDisposeDiagnostic(cx_diag, path);
+      // Filter messages like "too many errors emitted, stopping now
+      // [-ferror-limit=]" which has line = 0 and got subtracted by 1 after
+      // conversion to lsDiagnostic
+      if (diagnostic && diagnostic->range.start.line >= 0)
+        ls_diagnostics.push_back(*diagnostic);
+    }
+    completion_manager->on_diagnostic_(session->file.filename, ls_diagnostics);
   }
 }
 
 }  // namespace
 
-CompletionSession::CompletionSession(const Project::Entry& file,
-                                     WorkingFiles* working_files)
-    : file(file),
-      working_files(working_files),
-      index(0 /*excludeDeclarationsFromPCH*/, 0 /*displayDiagnostics*/) {}
-
-CompletionSession::~CompletionSession() {}
-
-ClangCompleteManager::ParseRequest::ParseRequest(const std::string& path)
-    : request_time(std::chrono::high_resolution_clock::now()), path(path) {}
-
-ClangCompleteManager::CompletionRequest::CompletionRequest(
-    const lsRequestId& id,
-    const lsTextDocumentIdentifier& document,
-    bool emit_diagnostics)
-    : id(id), document(document), emit_diagnostics(emit_diagnostics) {}
-ClangCompleteManager::CompletionRequest::CompletionRequest(
-    const lsRequestId& id,
-    const lsTextDocumentIdentifier& document,
-    const lsPosition& position,
-    const OnComplete& on_complete,
-    bool emit_diagnostics)
-    : id(id),
-      document(document),
-      position(position),
-      on_complete(on_complete),
-      emit_diagnostics(emit_diagnostics) {}
-
 ClangCompleteManager::ClangCompleteManager(Project* project,
                                            WorkingFiles* working_files,
                                            OnDiagnostic on_diagnostic,
@@ -677,13 +657,16 @@ ClangCompleteManager::ClangCompleteManager(Project* project,
       preloaded_sessions_(kMaxPreloadedSessions),
       completion_sessions_(kMaxCompletionSessions) {
   new std::thread([&]() {
-    SetThreadName("completequery");
+    SetThreadName("comp-query");
     CompletionQueryMain(this);
   });
-
   new std::thread([&]() {
-    SetThreadName("completeparse");
+    SetThreadName("comp-preload");
-    CompletionParseMain(this);
+    CompletionPreloadMain(this);
+  });
+  new std::thread([&]() {
+    SetThreadName("diag-query");
+    DiagnosticQueryMain(this);
   });
 }
 
@@ -693,14 +676,20 @@ void ClangCompleteManager::CodeComplete(
     const OnComplete& on_complete) {
   completion_request_.PushBack(std::make_unique<CompletionRequest>(
       id, completion_location.textDocument, completion_location.position,
-      on_complete, false));
+      on_complete));
 }
 
 void ClangCompleteManager::DiagnosticsUpdate(
     const lsRequestId& id,
     const lsTextDocumentIdentifier& document) {
-  completion_request_.PushBack(
+  bool has = false;
-      std::make_unique<CompletionRequest>(id, document, true));
+  diagnostic_request_.Iterate([&](const DiagnosticRequest& request) {
+    if (request.document.uri == document.uri)
+      has = true;
+  });
+  if (!has)
+    diagnostic_request_.PushBack(DiagnosticRequest{document},
+                                 true /*priority*/);
 }
 
 void ClangCompleteManager::NotifyView(const std::string& filename) {
@@ -712,7 +701,7 @@ void ClangCompleteManager::NotifyView(const std::string& filename) {
 
   // Only reparse the file if we create a new CompletionSession.
   if (EnsureCompletionOrCreatePreloadSession(filename))
-    parse_requests_.PushBack(ParseRequest(filename), true);
+    preload_requests_.PushBack(PreloadRequest(filename), true);
 }
 
 void ClangCompleteManager::NotifyEdit(const std::string& filename) {
@@ -731,7 +720,7 @@ void ClangCompleteManager::NotifySave(const std::string& filename) {
   //
 
   EnsureCompletionOrCreatePreloadSession(filename);
-  parse_requests_.PushBack(ParseRequest(filename), true);
+  preload_requests_.PushBack(PreloadRequest(filename), true);
 }
 
 void ClangCompleteManager::NotifyClose(const std::string& filename) {

src/clang_complete.h

@@ -18,22 +18,26 @@
 
 struct CompletionSession
     : public std::enable_shared_from_this<CompletionSession> {
+  // Translation unit for clang.
+  struct Tu {
+    ClangIndex index{0, 0};
+
+    // When |tu| was last parsed.
+    std::optional<std::chrono::time_point<std::chrono::high_resolution_clock>>
+        last_parsed_at;
+    // Acquired when |tu| is being used.
+    std::mutex lock;
+    std::unique_ptr<ClangTranslationUnit> tu;
+  };
+
   Project::Entry file;
   WorkingFiles* working_files;
-  ClangIndex index;
 
-  // When |tu| was last parsed.
+  Tu completion;
-  std::optional<std::chrono::time_point<std::chrono::high_resolution_clock>>
+  Tu diagnostics;
-      tu_last_parsed_at;
 
-  // Acquired when |tu| is being used.
+  CompletionSession(const Project::Entry& file, WorkingFiles* wfiles)
-  std::mutex tu_lock;
+      : file(file), working_files(wfiles) {}
-
-  // The active translation unit.
-  std::unique_ptr<ClangTranslationUnit> tu;
-
-  CompletionSession(const Project::Entry& file, WorkingFiles* working_files);
-  ~CompletionSession();
 };
 
 struct ClangCompleteManager {
@@ -49,27 +53,30 @@ struct ClangCompleteManager {
                          bool is_cached_result)>;
   using OnDropped = std::function<void(lsRequestId request_id)>;
 
-  struct ParseRequest {
+  struct PreloadRequest {
-    ParseRequest(const std::string& path);
+    PreloadRequest(const std::string& path)
+        : request_time(std::chrono::high_resolution_clock::now()), path(path) {}
 
     std::chrono::time_point<std::chrono::high_resolution_clock> request_time;
     std::string path;
   };
   struct CompletionRequest {
-    CompletionRequest(const lsRequestId& id,
-                      const lsTextDocumentIdentifier& document,
-                      bool emit_diagnostics);
     CompletionRequest(const lsRequestId& id,
                       const lsTextDocumentIdentifier& document,
                       const lsPosition& position,
-                      const OnComplete& on_complete,
+                      const OnComplete& on_complete)
-                      bool emit_diagnostics);
+        : id(id),
+          document(document),
+          position(position),
+          on_complete(on_complete) {}
 
     lsRequestId id;
     lsTextDocumentIdentifier document;
-    std::optional<lsPosition> position;
+    lsPosition position;
-    OnComplete on_complete;  // May be null/empty.
+    OnComplete on_complete;
-    bool emit_diagnostics = false;
+  };
+  struct DiagnosticRequest {
+    lsTextDocumentIdentifier document;
   };
 
   ClangCompleteManager(Project* project,
@@ -138,9 +145,10 @@ struct ClangCompleteManager {
 
   // Request a code completion at the given location.
   ThreadedQueue<std::unique_ptr<CompletionRequest>> completion_request_;
+  ThreadedQueue<DiagnosticRequest> diagnostic_request_;
   // Parse requests. The path may already be parsed, in which case it should be
   // reparsed.
-  ThreadedQueue<ParseRequest> parse_requests_;
+  ThreadedQueue<PreloadRequest> preload_requests_;
 };
 
 // Cached completion information, so we can give fast completion results when

src/messages/text_document_completion.cc

@@ -123,7 +123,7 @@ static const std::vector<std::string> preprocessorKeywords = {
     "define", "undef", "include", "if",   "ifdef", "ifndef",
     "else",   "elif",  "endif",   "line", "error", "pragma"};
 
-std::vector<lsCompletionItem> preprocessorKeywordCompletionItems(
+std::vector<lsCompletionItem> PreprocessorKeywordCompletionItems(
     const std::smatch& match) {
   std::vector<lsCompletionItem> items;
   for (auto& keyword : preprocessorKeywords) {
@@ -160,7 +160,8 @@ char* tofixedbase64(T input, char* out) {
 // when given 1000+ completion items.
 void FilterAndSortCompletionResponse(
     Out_TextDocumentComplete* complete_response,
-    const std::string& complete_text) {
+    const std::string& complete_text,
+    bool has_open_paren) {
   if (!g_config->completion.filterAndSort)
     return;
 
@@ -189,6 +190,10 @@ void FilterAndSortCompletionResponse(
       complete_response->result.isIncomplete = true;
     }
 
+    if (has_open_paren)
+      for (auto& item: items)
+        item.insertText = item.label;
+
     // Set sortText. Note that this happens after resizing - we could do it
     // before, but then we should also sort by priority.
     char buf[16];
@@ -236,6 +241,26 @@ void FilterAndSortCompletionResponse(
   finalize();
 }
 
+// Returns true if position is an points to a '(' character in |lines|. Skips
+// whitespace.
+bool IsOpenParenOrAngle(const std::vector<std::string>& lines,
+  const lsPosition& position) {
+  auto [c, l] = position;
+  while (l < lines.size()) {
+    const auto& line = lines[l];
+    if (c >= line.size())
+      return false;
+    if (line[c] == '(' || line[c] == '<')
+      return true;
+    if (!isspace(line[c])) break;
+    if (++c >= line.size()) {
+      c = 0;
+      l++;
+    }
+  }
+  return false;
+}
+
 struct Handler_TextDocumentCompletion : MessageHandler {
   MethodType GetMethodType() const override { return kMethodType; }
 
@@ -306,13 +331,15 @@ struct Handler_TextDocumentCompletion : MessageHandler {
 
     bool is_global_completion = false;
     std::string existing_completion;
+    lsPosition end_pos = request->params.position;
     if (file) {
       request->params.position = file->FindStableCompletionSource(
           request->params.position, &is_global_completion,
-          &existing_completion);
+          &existing_completion, &end_pos);
     }
 
     ParseIncludeLineResult result = ParseIncludeLine(buffer_line);
+    bool has_open_paren = IsOpenParenOrAngle(file->buffer_lines, end_pos);
 
     if (result.ok) {
       Out_TextDocumentComplete out;
@@ -325,8 +352,8 @@ struct Handler_TextDocumentCompletion : MessageHandler {
                          [&result](std::string_view k) {
                            return k == result.keyword;
                          })) {
-          out.result.items = preprocessorKeywordCompletionItems(result.match);
+          out.result.items = PreprocessorKeywordCompletionItems(result.match);
-          FilterAndSortCompletionResponse(&out, result.keyword);
+          FilterAndSortCompletionResponse(&out, result.keyword, has_open_paren);
         }
       } else if (result.keyword.compare("include") == 0) {
         {
@@ -340,7 +367,7 @@ struct Handler_TextDocumentCompletion : MessageHandler {
             if (quote.empty() || quote == (item.use_angle_brackets_ ? "<" : "\""))
                out.result.items.push_back(item);
         }
-        FilterAndSortCompletionResponse(&out, result.pattern);
+        FilterAndSortCompletionResponse(&out, result.pattern, has_open_paren);
         DecorateIncludePaths(result.match, &out.result.items);
       }
 
@@ -354,15 +381,15 @@ struct Handler_TextDocumentCompletion : MessageHandler {
       QueueManager::WriteStdout(kMethodType, out);
     } else {
       ClangCompleteManager::OnComplete callback = std::bind(
-          [this, is_global_completion, existing_completion, request](
+          [this, request, is_global_completion, existing_completion,
-              const std::vector<lsCompletionItem>& results,
+           has_open_paren](const std::vector<lsCompletionItem>& results,
-              bool is_cached_result) {
+                           bool is_cached_result) {
             Out_TextDocumentComplete out;
             out.id = request->id;
             out.result.items = results;
 
             // Emit completion results.
-            FilterAndSortCompletionResponse(&out, existing_completion);
+            FilterAndSortCompletionResponse(&out, existing_completion, has_open_paren);
             QueueManager::WriteStdout(kMethodType, out);
 
             // Cache completion results.

src/threaded_queue.h

@@ -205,6 +205,15 @@ struct ThreadedQueue : public BaseThreadQueue {
 
   std::optional<T> TryPopFrontHigh() { return TryPopFrontHelper(2); }
 
+  template <typename Fn>
+  void Iterate(Fn fn) {
+    std::lock_guard<std::mutex> lock(mutex_);
+    for (auto& entry : priority_)
+      fn(entry);
+    for (auto& entry : queue_)
+      fn(entry);
+  }
+
   mutable std::mutex mutex_;
 
  private:

src/working_files.cc

@@ -415,7 +415,8 @@ std::string WorkingFile::FindClosestCallNameInBuffer(
 lsPosition WorkingFile::FindStableCompletionSource(
     lsPosition position,
     bool* is_global_completion,
-    std::string* existing_completion) const {
+    std::string* existing_completion,
+    lsPosition* replace_end_pos) const {
   *is_global_completion = true;
 
   int start_offset = GetOffsetForPosition(position, buffer_content);
@@ -441,6 +442,14 @@ lsPosition WorkingFile::FindStableCompletionSource(
     --offset;
   }
 
+  *replace_end_pos = position;
+  for (int i = start_offset; i < buffer_content.size(); i++) {
+    char c = buffer_content[i];
+    if (!isalnum(c) && c != '_') break;
+    // We know that replace_end_pos and position are on the same line.
+    replace_end_pos->character++;
+  }
+
   *existing_completion = buffer_content.substr(offset, start_offset - offset);
   return GetPositionForOffset(buffer_content, offset);
 }

src/working_files.h

@@ -69,7 +69,8 @@ struct WorkingFile {
   // content the user has entered.
   lsPosition FindStableCompletionSource(lsPosition position,
                                         bool* is_global_completion,
-                                        std::string* existing_completion) const;
+                                        std::string* existing_completion,
+                                        lsPosition* replace_end_pos) const;
 
  private:
   // Compute index_to_buffer and buffer_to_index.