diff --git a/CMakeLists.txt b/CMakeLists.txt
index f3bdd59f..52f0f269 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -189,11 +189,8 @@ file(GLOB SOURCES src/*.cc src/*.h src/serializers/*.cc src/serializers/*.h
 target_sources(ccls PRIVATE third_party/siphash.cc)
 
 target_sources(ccls PRIVATE
-               src/cache_manager.cc
                src/clang_complete.cc
-               src/clang_cursor.cc
-               src/clang_indexer.cc
-               src/clang_translation_unit.cc
+               src/clang_tu.cc
                src/clang_utils.cc
                src/config.cc
                src/diagnostics_engine.cc
@@ -202,6 +199,7 @@ target_sources(ccls PRIVATE
                src/fuzzy_match.cc
                src/main.cc
                src/include_complete.cc
+               src/indexer.cc
                src/method.cc
                src/language.cc
                src/lex_utils.cc
@@ -212,12 +210,10 @@ target_sources(ccls PRIVATE
                src/pipeline.cc
                src/platform_posix.cc
                src/platform_win.cc
-               src/port.cc
                src/position.cc
                src/project.cc
                src/query_utils.cc
                src/query.cc
-               src/queue_manager.cc
                src/serializer.cc
                src/test.cc
                src/third_party_impl.cc
diff --git a/src/cache_manager.cc b/src/cache_manager.cc
deleted file mode 100644
index c3e64788..00000000
--- a/src/cache_manager.cc
+++ /dev/null
@@ -1,62 +0,0 @@
-#include "cache_manager.h"
-
-#include "config.h"
-#include "indexer.h"
-#include "lsp.h"
-#include "platform.h"
-
-#include <algorithm>
-#include <unordered_map>
-
-namespace {
-std::string GetCachePath(const std::string& source_file) {
-  assert(!g_config->cacheDirectory.empty());
-  std::string cache_file;
-  size_t len = g_config->projectRoot.size();
-  if (StartsWith(source_file, g_config->projectRoot)) {
-    cache_file = EscapeFileName(g_config->projectRoot) +
-                 EscapeFileName(source_file.substr(len));
-  } else {
-    cache_file = '@' + EscapeFileName(g_config->projectRoot) +
-                 EscapeFileName(source_file);
-  }
-
-  return g_config->cacheDirectory + cache_file;
-}
-
-std::string AppendSerializationFormat(const std::string& base) {
-  switch (g_config->cacheFormat) {
-    case SerializeFormat::Binary:
-      return base + ".blob";
-    case SerializeFormat::Json:
-      return base + ".json";
-  }
-}
-}
-
-// Manages loading caches from file paths for the indexer process.
-void ICacheManager::WriteToCache(IndexFile& file) {
-  std::string cache_path = GetCachePath(file.path);
-  WriteToFile(cache_path, file.file_contents);
-
-  std::string indexed_content = Serialize(g_config->cacheFormat, file);
-  WriteToFile(AppendSerializationFormat(cache_path), indexed_content);
-}
-
-std::optional<std::string> ICacheManager::LoadCachedFileContents(
-    const std::string& path) {
-  return ReadContent(GetCachePath(path));
-}
-
-std::unique_ptr<IndexFile> ICacheManager::RawCacheLoad(
-    const std::string& path) {
-  std::string cache_path = GetCachePath(path);
-  std::optional<std::string> file_content = ReadContent(cache_path);
-  std::optional<std::string> serialized_indexed_content =
-      ReadContent(AppendSerializationFormat(cache_path));
-  if (!file_content || !serialized_indexed_content)
-    return nullptr;
-
-  return Deserialize(g_config->cacheFormat, path, *serialized_indexed_content,
-                     *file_content, IndexFile::kMajorVersion);
-}
diff --git a/src/cache_manager.h b/src/cache_manager.h
deleted file mode 100644
index daffdd48..00000000
--- a/src/cache_manager.h
+++ /dev/null
@@ -1,26 +0,0 @@
-#pragma once
-
-#include <optional>
-
-#include <memory>
-#include <string>
-#include <unordered_map>
-#include <vector>
-
-struct IndexFile;
-
-struct ICacheManager {
-  void WriteToCache(IndexFile& file);
-
-  std::optional<std::string> LoadCachedFileContents(const std::string& path);
-
-  template <typename Fn>
-  void IterateLoadedCaches(Fn fn) {
-    for (const auto& cache : caches_)
-      fn(cache.second.get());
-  }
-
-  std::unique_ptr<IndexFile> RawCacheLoad(const std::string& path);
-
-  std::unordered_map<std::string, std::unique_ptr<IndexFile>> caches_;
-};
diff --git a/src/clang_complete.cc b/src/clang_complete.cc
index e06c7647..f35c9429 100644
--- a/src/clang_complete.cc
+++ b/src/clang_complete.cc
@@ -21,14 +21,8 @@ unsigned Flags() {
          CXTranslationUnit_CacheCompletionResults |
          CXTranslationUnit_PrecompiledPreamble |
          CXTranslationUnit_IncludeBriefCommentsInCodeCompletion |
-         CXTranslationUnit_DetailedPreprocessingRecord
-#if !defined(_WIN32)
-         // For whatever reason, CreatePreambleOnFirstParse causes clang to
-         // become very crashy on windows.
-         // TODO: do more investigation, submit fixes to clang.
-         | CXTranslationUnit_CreatePreambleOnFirstParse
-#endif
-      ;
+         CXTranslationUnit_DetailedPreprocessingRecord |
+         CXTranslationUnit_CreatePreambleOnFirstParse;
 }
 
 std::string StripFileType(const std::string& path) {
@@ -57,23 +51,6 @@ unsigned GetCompletionPriority(const CXCompletionString& str,
   return priority;
 }
 
-/*
-bool IsCallKind(CXCursorKind kind) {
-  switch (kind) {
-    case CXCursor_ObjCInstanceMethodDecl:
-    case CXCursor_CXXMethod:
-    case CXCursor_FunctionTemplate:
-    case CXCursor_FunctionDecl:
-    case CXCursor_Constructor:
-    case CXCursor_Destructor:
-    case CXCursor_ConversionFunction:
-      return true;
-    default:
-      return false;
-  }
-}
-*/
-
 lsCompletionItemKind GetCompletionKind(CXCursorKind cursor_kind) {
   switch (cursor_kind) {
     case CXCursor_UnexposedDecl:
@@ -383,8 +360,8 @@ void TryEnsureDocumentParsed(ClangCompleteManager* manager,
   std::vector<std::string> args = session->file.args;
 
   // -fspell-checking enables FixIts for, ie, misspelled types.
-  if (!AnyStartsWith(args, "-fno-spell-checking") &&
-      !AnyStartsWith(args, "-fspell-checking")) {
+  if (!std::count(args.begin(), args.end(), "-fno-spell-checking") &&
+      !std::count(args.begin(), args.end(), "-fspell-checking")) {
     args.push_back("-fspell-checking");
   }
 
diff --git a/src/clang_complete.h b/src/clang_complete.h
index aa471c8e..af824df1 100644
--- a/src/clang_complete.h
+++ b/src/clang_complete.h
@@ -1,7 +1,6 @@
 #pragma once
 
-#include "clang_cursor.h"
-#include "clang_translation_unit.h"
+#include "clang_tu.h"
 #include "lru_cache.h"
 #include "lsp_completion.h"
 #include "lsp_diagnostic.h"
diff --git a/src/clang_translation_unit.cc b/src/clang_translation_unit.cc
deleted file mode 100644
index f9f9aaf4..00000000
--- a/src/clang_translation_unit.cc
+++ /dev/null
@@ -1,155 +0,0 @@
-#include "clang_translation_unit.h"
-
-#include "clang_utils.h"
-#include "log.hh"
-#include "platform.h"
-#include "utils.h"
-
-namespace {
-
-void EmitDiagnostics(std::string path,
-                     std::vector<const char*> args,
-                     CXTranslationUnit tu) {
-  std::string output = "Fatal errors while trying to parse " + path + "\n";
-  output +=
-      "Args: " +
-      StringJoinMap(args, [](const char* arg) { return std::string(arg); }) +
-      "\n";
-
-  size_t num_diagnostics = clang_getNumDiagnostics(tu);
-  for (unsigned i = 0; i < num_diagnostics; ++i) {
-    output += "  - ";
-
-    CXDiagnostic diagnostic = clang_getDiagnostic(tu, i);
-
-    // Location.
-    CXFile file;
-    unsigned int line, column;
-    clang_getSpellingLocation(clang_getDiagnosticLocation(diagnostic), &file,
-                              &line, &column, nullptr);
-    std::string path = FileName(file);
-    output += path + ":" + std::to_string(line - 1) + ":" +
-              std::to_string(column) + " ";
-
-    // Severity
-    switch (clang_getDiagnosticSeverity(diagnostic)) {
-      case CXDiagnostic_Ignored:
-      case CXDiagnostic_Note:
-        output += "[info]";
-        break;
-      case CXDiagnostic_Warning:
-        output += "[warning]";
-        break;
-      case CXDiagnostic_Error:
-        output += "[error]";
-        break;
-      case CXDiagnostic_Fatal:
-        output += "[fatal]";
-        break;
-    }
-
-    // Content.
-    output += " " + ToString(clang_getDiagnosticSpelling(diagnostic));
-
-    clang_disposeDiagnostic(diagnostic);
-
-    output += "\n";
-  }
-
-  LOG_S(WARNING) << output;
-}
-}  // namespace
-
-// static
-std::unique_ptr<ClangTranslationUnit> ClangTranslationUnit::Create(
-    ClangIndex* index,
-    const std::string& filepath,
-    const std::vector<std::string>& arguments,
-    std::vector<CXUnsavedFile>& unsaved_files,
-    unsigned flags) {
-  std::vector<const char*> args;
-  for (auto& arg : arguments)
-    args.push_back(arg.c_str());
-
-  CXTranslationUnit cx_tu;
-  CXErrorCode error_code;
-  {
-    error_code = clang_parseTranslationUnit2FullArgv(
-        index->cx_index, nullptr, args.data(), (int)args.size(),
-        unsaved_files.data(), (unsigned)unsaved_files.size(), flags, &cx_tu);
-  }
-
-  if (error_code != CXError_Success && cx_tu)
-    EmitDiagnostics(filepath, args, cx_tu);
-
-  // We sometimes dump the command to logs and ask the user to run it. Include
-  // -fsyntax-only so they don't do a full compile.
-  auto make_msg = [&]() {
-    return "Please try running the following, identify which flag causes the "
-           "issue, and report a bug. ccls will then filter the flag for you "
-           " automatically:\n " +
-           StringJoin(args, " ") + " -fsyntax-only";
-  };
-
-  switch (error_code) {
-    case CXError_Success:
-      return std::make_unique<ClangTranslationUnit>(cx_tu);
-    case CXError_Failure:
-      LOG_S(ERROR) << "libclang generic failure for " << filepath << ". "
-                   << make_msg();
-      return nullptr;
-    case CXError_Crashed:
-      LOG_S(ERROR) << "libclang crashed for " << filepath << ". " << make_msg();
-      return nullptr;
-    case CXError_InvalidArguments:
-      LOG_S(ERROR) << "libclang had invalid arguments for " << filepath << ". "
-                   << make_msg();
-      return nullptr;
-    case CXError_ASTReadError:
-      LOG_S(ERROR) << "libclang had ast read error for " << filepath << ". "
-                   << make_msg();
-      return nullptr;
-  }
-
-  return nullptr;
-}
-
-// static
-std::unique_ptr<ClangTranslationUnit> ClangTranslationUnit::Reparse(
-    std::unique_ptr<ClangTranslationUnit> tu,
-    std::vector<CXUnsavedFile>& unsaved) {
-  int error_code;
-  {
-    error_code = clang_reparseTranslationUnit(
-        tu->cx_tu, (unsigned)unsaved.size(), unsaved.data(),
-        clang_defaultReparseOptions(tu->cx_tu));
-  }
-
-  if (error_code != CXError_Success && tu->cx_tu)
-    EmitDiagnostics("<unknown>", {}, tu->cx_tu);
-
-  switch (error_code) {
-    case CXError_Success:
-      return tu;
-    case CXError_Failure:
-      LOG_S(ERROR) << "libclang reparse generic failure";
-      return nullptr;
-    case CXError_Crashed:
-      LOG_S(ERROR) << "libclang reparse crashed";
-      return nullptr;
-    case CXError_InvalidArguments:
-      LOG_S(ERROR) << "libclang reparse had invalid arguments";
-      return nullptr;
-    case CXError_ASTReadError:
-      LOG_S(ERROR) << "libclang reparse had ast read error";
-      return nullptr;
-  }
-
-  return nullptr;
-}
-
-ClangTranslationUnit::ClangTranslationUnit(CXTranslationUnit tu) : cx_tu(tu) {}
-
-ClangTranslationUnit::~ClangTranslationUnit() {
-  clang_disposeTranslationUnit(cx_tu);
-}
diff --git a/src/clang_translation_unit.h b/src/clang_translation_unit.h
deleted file mode 100644
index 59e2f17f..00000000
--- a/src/clang_translation_unit.h
+++ /dev/null
@@ -1,30 +0,0 @@
-#pragma once
-
-#include "clang_cursor.h"
-
-#include <clang-c/Index.h>
-
-#include <memory>
-#include <string>
-#include <vector>
-
-// RAII wrapper around CXTranslationUnit which also makes it much more
-// challenging to use a CXTranslationUnit instance that is not correctly
-// initialized.
-struct ClangTranslationUnit {
-  static std::unique_ptr<ClangTranslationUnit> Create(
-      ClangIndex* index,
-      const std::string& filepath,
-      const std::vector<std::string>& arguments,
-      std::vector<CXUnsavedFile>& unsaved_files,
-      unsigned flags);
-
-  static std::unique_ptr<ClangTranslationUnit> Reparse(
-      std::unique_ptr<ClangTranslationUnit> tu,
-      std::vector<CXUnsavedFile>& unsaved);
-
-  explicit ClangTranslationUnit(CXTranslationUnit tu);
-  ~ClangTranslationUnit();
-
-  CXTranslationUnit cx_tu;
-};
diff --git a/src/clang_cursor.cc b/src/clang_tu.cc
similarity index 64%
rename from src/clang_cursor.cc
rename to src/clang_tu.cc
index ab880b3d..dbb1d89d 100644
--- a/src/clang_cursor.cc
+++ b/src/clang_tu.cc
@@ -1,12 +1,70 @@
-#include "clang_cursor.h"
+#include "clang_tu.h"
 
 #include "clang_utils.h"
+#include "log.hh"
+#include "platform.h"
+#include "utils.h"
 
 #include <assert.h>
 #include <string.h>
 #include <algorithm>
 #include <mutex>
 
+namespace {
+
+void EmitDiagnostics(std::string path,
+                     std::vector<const char*> args,
+                     CXTranslationUnit tu) {
+  std::string output = "Fatal errors while trying to parse " + path + "\n";
+  output +=
+      "Args: " +
+      StringJoinMap(args, [](const char* arg) { return std::string(arg); }) +
+      "\n";
+
+  size_t num_diagnostics = clang_getNumDiagnostics(tu);
+  for (unsigned i = 0; i < num_diagnostics; ++i) {
+    output += "  - ";
+
+    CXDiagnostic diagnostic = clang_getDiagnostic(tu, i);
+
+    // Location.
+    CXFile file;
+    unsigned int line, column;
+    clang_getSpellingLocation(clang_getDiagnosticLocation(diagnostic), &file,
+                              &line, &column, nullptr);
+    std::string path = FileName(file);
+    output += path + ":" + std::to_string(line - 1) + ":" +
+              std::to_string(column) + " ";
+
+    // Severity
+    switch (clang_getDiagnosticSeverity(diagnostic)) {
+      case CXDiagnostic_Ignored:
+      case CXDiagnostic_Note:
+        output += "[info]";
+        break;
+      case CXDiagnostic_Warning:
+        output += "[warning]";
+        break;
+      case CXDiagnostic_Error:
+        output += "[error]";
+        break;
+      case CXDiagnostic_Fatal:
+        output += "[fatal]";
+        break;
+    }
+
+    // Content.
+    output += " " + ToString(clang_getDiagnosticSpelling(diagnostic));
+
+    clang_disposeDiagnostic(diagnostic);
+
+    output += "\n";
+  }
+
+  LOG_S(WARNING) << output;
+}
+}  // namespace
+
 Range ResolveCXSourceRange(const CXSourceRange& range, CXFile* cx_file) {
   CXSourceLocation start = clang_getRangeStart(range);
   CXSourceLocation end = clang_getRangeEnd(range);
@@ -284,3 +342,97 @@ ClangIndex::ClangIndex(int exclude_declarations_from_pch,
 ClangIndex::~ClangIndex() {
   clang_disposeIndex(cx_index);
 }
+
+// static
+std::unique_ptr<ClangTranslationUnit> ClangTranslationUnit::Create(
+    ClangIndex* index,
+    const std::string& filepath,
+    const std::vector<std::string>& arguments,
+    std::vector<CXUnsavedFile>& unsaved_files,
+    unsigned flags) {
+  std::vector<const char*> args;
+  for (auto& arg : arguments)
+    args.push_back(arg.c_str());
+
+  CXTranslationUnit cx_tu;
+  CXErrorCode error_code;
+  {
+    error_code = clang_parseTranslationUnit2FullArgv(
+        index->cx_index, nullptr, args.data(), (int)args.size(),
+        unsaved_files.data(), (unsigned)unsaved_files.size(), flags, &cx_tu);
+  }
+
+  if (error_code != CXError_Success && cx_tu)
+    EmitDiagnostics(filepath, args, cx_tu);
+
+  // We sometimes dump the command to logs and ask the user to run it. Include
+  // -fsyntax-only so they don't do a full compile.
+  auto make_msg = [&]() {
+    return "Please try running the following, identify which flag causes the "
+           "issue, and report a bug. ccls will then filter the flag for you "
+           " automatically:\n " +
+           StringJoin(args, " ") + " -fsyntax-only";
+  };
+
+  switch (error_code) {
+    case CXError_Success:
+      return std::make_unique<ClangTranslationUnit>(cx_tu);
+    case CXError_Failure:
+      LOG_S(ERROR) << "libclang generic failure for " << filepath << ". "
+                   << make_msg();
+      return nullptr;
+    case CXError_Crashed:
+      LOG_S(ERROR) << "libclang crashed for " << filepath << ". " << make_msg();
+      return nullptr;
+    case CXError_InvalidArguments:
+      LOG_S(ERROR) << "libclang had invalid arguments for " << filepath << ". "
+                   << make_msg();
+      return nullptr;
+    case CXError_ASTReadError:
+      LOG_S(ERROR) << "libclang had ast read error for " << filepath << ". "
+                   << make_msg();
+      return nullptr;
+  }
+
+  return nullptr;
+}
+
+// static
+std::unique_ptr<ClangTranslationUnit> ClangTranslationUnit::Reparse(
+    std::unique_ptr<ClangTranslationUnit> tu,
+    std::vector<CXUnsavedFile>& unsaved) {
+  int error_code;
+  {
+    error_code = clang_reparseTranslationUnit(
+        tu->cx_tu, (unsigned)unsaved.size(), unsaved.data(),
+        clang_defaultReparseOptions(tu->cx_tu));
+  }
+
+  if (error_code != CXError_Success && tu->cx_tu)
+    EmitDiagnostics("<unknown>", {}, tu->cx_tu);
+
+  switch (error_code) {
+    case CXError_Success:
+      return tu;
+    case CXError_Failure:
+      LOG_S(ERROR) << "libclang reparse generic failure";
+      return nullptr;
+    case CXError_Crashed:
+      LOG_S(ERROR) << "libclang reparse crashed";
+      return nullptr;
+    case CXError_InvalidArguments:
+      LOG_S(ERROR) << "libclang reparse had invalid arguments";
+      return nullptr;
+    case CXError_ASTReadError:
+      LOG_S(ERROR) << "libclang reparse had ast read error";
+      return nullptr;
+  }
+
+  return nullptr;
+}
+
+ClangTranslationUnit::ClangTranslationUnit(CXTranslationUnit tu) : cx_tu(tu) {}
+
+ClangTranslationUnit::~ClangTranslationUnit() {
+  clang_disposeTranslationUnit(cx_tu);
+}
diff --git a/src/clang_cursor.h b/src/clang_tu.h
similarity index 82%
rename from src/clang_cursor.h
rename to src/clang_tu.h
index 67acd08b..2530b2de 100644
--- a/src/clang_cursor.h
+++ b/src/clang_tu.h
@@ -1,12 +1,10 @@
 #pragma once
-
 #include "nt_string.h"
 #include "position.h"
 
 #include <clang-c/Index.h>
-#include <optional>
 
-#include <array>
+#include <memory>
 #include <string>
 #include <vector>
 
@@ -119,3 +117,24 @@ class ClangIndex {
   ~ClangIndex();
   CXIndex cx_index;
 };
+
+// RAII wrapper around CXTranslationUnit which also makes it much more
+// challenging to use a CXTranslationUnit instance that is not correctly
+// initialized.
+struct ClangTranslationUnit {
+  static std::unique_ptr<ClangTranslationUnit> Create(
+      ClangIndex* index,
+      const std::string& filepath,
+      const std::vector<std::string>& arguments,
+      std::vector<CXUnsavedFile>& unsaved_files,
+      unsigned flags);
+
+  static std::unique_ptr<ClangTranslationUnit> Reparse(
+      std::unique_ptr<ClangTranslationUnit> tu,
+      std::vector<CXUnsavedFile>& unsaved);
+
+  explicit ClangTranslationUnit(CXTranslationUnit tu);
+  ~ClangTranslationUnit();
+
+  CXTranslationUnit cx_tu;
+};
diff --git a/src/diagnostics_engine.cc b/src/diagnostics_engine.cc
index 3e7ce0f7..c714ec9b 100644
--- a/src/diagnostics_engine.cc
+++ b/src/diagnostics_engine.cc
@@ -1,6 +1,7 @@
 #include "diagnostics_engine.h"
 
-#include "queue_manager.h"
+#include "pipeline.hh"
+using namespace ccls;
 
 #include <chrono>
 
@@ -30,6 +31,6 @@ void DiagnosticsEngine::Publish(WorkingFiles* working_files,
     Out_TextDocumentPublishDiagnostics out;
     out.params.uri = lsDocumentUri::FromPath(path);
     out.params.diagnostics = diagnostics;
-    QueueManager::WriteStdout(kMethodType_TextDocumentPublishDiagnostics, out);
+    pipeline::WriteStdout(kMethodType_TextDocumentPublishDiagnostics, out);
   }
 }
diff --git a/src/include_complete.cc b/src/include_complete.cc
index 1d1b74a1..5fb6c9b1 100644
--- a/src/include_complete.cc
+++ b/src/include_complete.cc
@@ -107,7 +107,7 @@ void IncludeComplete::Rescan() {
 
   is_scanning = true;
   std::thread([this]() {
-    set_thread_name("scan_includes");
+    set_thread_name("include");
     Timer timer;
 
     for (const std::string& dir : project_->quote_include_directories)
diff --git a/src/clang_indexer.cc b/src/indexer.cc
similarity index 99%
rename from src/clang_indexer.cc
rename to src/indexer.cc
index a9d66986..0794a5f3 100644
--- a/src/clang_indexer.cc
+++ b/src/indexer.cc
@@ -1,7 +1,5 @@
 #include "indexer.h"
 
-#include "clang_cursor.h"
-#include "clang_utils.h"
 #include "log.hh"
 #include "platform.h"
 #include "serializer.h"
diff --git a/src/indexer.h b/src/indexer.h
index 2c35784e..ae29f918 100644
--- a/src/indexer.h
+++ b/src/indexer.h
@@ -1,7 +1,6 @@
 #pragma once
 
-#include "clang_cursor.h"
-#include "clang_translation_unit.h"
+#include "clang_tu.h"
 #include "clang_utils.h"
 #include "file_consumer.h"
 #include "language.h"
diff --git a/src/main.cc b/src/main.cc
index fcfc66e9..03936f5c 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -5,6 +5,7 @@
 #include "serializers/json.h"
 #include "test.h"
 #include "working_files.h"
+using namespace ccls;
 
 #include <llvm/Support/CommandLine.h>
 #include <llvm/Support/Process.h>
@@ -56,8 +57,7 @@ int main(int argc, char** argv) {
       return 0;
   }
 
-  MultiQueueWaiter querydb_waiter, indexer_waiter, stdout_waiter;
-  QueueManager::Init(&querydb_waiter, &indexer_waiter, &stdout_waiter);
+  pipeline::Init();
 
 #ifdef _WIN32
   // We need to write to stdout in binary mode because in Windows, writing
@@ -132,11 +132,11 @@ int main(int argc, char** argv) {
     std::unordered_map<MethodType, Timer> request_times;
 
     // The thread that reads from stdin and dispatchs commands to the main thread.
-    LaunchStdinLoop(&request_times);
+    pipeline::LaunchStdin(&request_times);
     // The thread that writes responses from the main thread to stdout.
-    LaunchStdoutThread(&request_times, &stdout_waiter);
+    pipeline::LaunchStdout(&request_times);
     // Main thread which also spawns indexer threads upon the "initialize" request.
-    MainLoop(&querydb_waiter, &indexer_waiter);
+    pipeline::MainLoop();
   }
 
   return 0;
diff --git a/src/match.cc b/src/match.cc
index 6f6bda56..178095d6 100644
--- a/src/match.cc
+++ b/src/match.cc
@@ -1,7 +1,8 @@
 #include "match.h"
 
 #include "lsp.h"
-#include "queue_manager.h"
+#include "pipeline.hh"
+using namespace ccls;
 
 #include <doctest/doctest.h>
 
@@ -32,7 +33,7 @@ std::optional<Matcher> Matcher::Create(const std::string& search) {
     out.params.type = lsMessageType::Error;
     out.params.message = "ccls: Parsing EMCAScript regex \"" + search +
                          "\" failed; " + e.what();
-    QueueManager::WriteStdout(kMethodType_Unknown, out);
+    pipeline::WriteStdout(kMethodType_Unknown, out);
     return std::nullopt;
   }
 }
diff --git a/src/message_handler.cc b/src/message_handler.cc
index a0014c21..cd7915e5 100644
--- a/src/message_handler.cc
+++ b/src/message_handler.cc
@@ -4,7 +4,8 @@
 #include "log.hh"
 #include "project.h"
 #include "query_utils.h"
-#include "queue_manager.h"
+#include "pipeline.hh"
+using namespace ccls;
 
 #include <algorithm>
 
@@ -167,7 +168,7 @@ bool FindFileOrFail(QueryDatabase* db,
       out.error.code = lsErrorCodes::InternalError;
       out.error.message = "Unable to find file " + absolute_path;
     }
-    QueueManager::WriteStdout(kMethodType_Unknown, out);
+    pipeline::WriteStdout(kMethodType_Unknown, out);
   }
 
   return false;
@@ -182,7 +183,7 @@ void EmitInactiveLines(WorkingFile* working_file,
     if (ls_skipped)
       out.params.inactiveRegions.push_back(*ls_skipped);
   }
-  QueueManager::WriteStdout(kMethodType_CclsPublishInactiveRegions, out);
+  pipeline::WriteStdout(kMethodType_CclsPublishInactiveRegions, out);
 }
 
 void EmitSemanticHighlighting(QueryDatabase* db,
@@ -343,5 +344,5 @@ void EmitSemanticHighlighting(QueryDatabase* db,
   for (auto& entry : grouped_symbols)
     if (entry.second.ranges.size())
       out.params.symbols.push_back(entry.second);
-  QueueManager::WriteStdout(kMethodType_CclsPublishSemanticHighlighting, out);
+  pipeline::WriteStdout(kMethodType_CclsPublishSemanticHighlighting, out);
 }
diff --git a/src/messages/ccls_base.cc b/src/messages/ccls_base.cc
index 80413762..fa04a498 100644
--- a/src/messages/ccls_base.cc
+++ b/src/messages/ccls_base.cc
@@ -1,6 +1,7 @@
 #include "message_handler.h"
+#include "pipeline.hh"
 #include "query_utils.h"
-#include "queue_manager.h"
+using namespace ccls;
 
 namespace {
 
@@ -43,7 +44,7 @@ struct Handler_CclsBase : BaseMessageHandler<In_CclsBase> {
         break;
       }
     }
-    QueueManager::WriteStdout(kMethodType, out);
+    pipeline::WriteStdout(kMethodType, out);
   }
 };
 REGISTER_MESSAGE_HANDLER(Handler_CclsBase);
diff --git a/src/messages/ccls_call_hierarchy.cc b/src/messages/ccls_call_hierarchy.cc
index 08c94515..2911d75d 100644
--- a/src/messages/ccls_call_hierarchy.cc
+++ b/src/messages/ccls_call_hierarchy.cc
@@ -1,6 +1,8 @@
 #include "message_handler.h"
+#include "pipeline.hh"
+using namespace ccls;
 #include "query_utils.h"
-#include "queue_manager.h"
+using namespace ccls;
 
 #include <unordered_set>
 
@@ -225,7 +227,7 @@ struct Handler_CclsCallHierarchy
       }
     }
 
-    QueueManager::WriteStdout(kMethodType, out);
+    pipeline::WriteStdout(kMethodType, out);
   }
 };
 REGISTER_MESSAGE_HANDLER(Handler_CclsCallHierarchy);
diff --git a/src/messages/ccls_callers.cc b/src/messages/ccls_callers.cc
index db781be9..4325d3b7 100644
--- a/src/messages/ccls_callers.cc
+++ b/src/messages/ccls_callers.cc
@@ -1,6 +1,7 @@
 #include "message_handler.h"
+#include "pipeline.hh"
 #include "query_utils.h"
-#include "queue_manager.h"
+using namespace ccls;
 
 namespace {
 MethodType kMethodType = "$ccls/callers";
@@ -39,7 +40,7 @@ struct Handler_CclsCallers : BaseMessageHandler<In_CclsCallers> {
         break;
       }
     }
-    QueueManager::WriteStdout(kMethodType, out);
+    pipeline::WriteStdout(kMethodType, out);
   }
 };
 REGISTER_MESSAGE_HANDLER(Handler_CclsCallers);
diff --git a/src/messages/ccls_file_info.cc b/src/messages/ccls_file_info.cc
index cbd6ed78..689ef1f9 100644
--- a/src/messages/ccls_file_info.cc
+++ b/src/messages/ccls_file_info.cc
@@ -1,6 +1,7 @@
 #include "message_handler.h"
+#include "pipeline.hh"
 #include "query_utils.h"
-#include "queue_manager.h"
+using namespace ccls;
 
 MAKE_REFLECT_STRUCT(QueryFile::Def,
                     path,
@@ -49,7 +50,7 @@ struct Handler_CclsFileInfo : BaseMessageHandler<In_CclsFileInfo> {
     out.result.language = file->def->language;
     out.result.includes = file->def->includes;
     out.result.inactive_regions = file->def->inactive_regions;
-    QueueManager::WriteStdout(kMethodType, out);
+    pipeline::WriteStdout(kMethodType, out);
   }
 };
 REGISTER_MESSAGE_HANDLER(Handler_CclsFileInfo);
diff --git a/src/messages/ccls_freshen_index.cc b/src/messages/ccls_freshen_index.cc
index bf36450f..6584b373 100644
--- a/src/messages/ccls_freshen_index.cc
+++ b/src/messages/ccls_freshen_index.cc
@@ -1,12 +1,11 @@
-#include "cache_manager.h"
 #include "match.h"
 #include "message_handler.h"
-#include "pipeline.hh"
 #include "platform.h"
 #include "project.h"
-#include "queue_manager.h"
+#include "pipeline.hh"
 #include "timer.h"
 #include "working_files.h"
+using namespace ccls;
 
 #include <queue>
 #include <unordered_set>
@@ -79,7 +78,7 @@ struct Handler_CclsFreshenIndex : BaseMessageHandler<In_CclsFreshenIndex> {
     }
 
     // Send index requests for every file.
-    project->Index(QueueManager::instance(), working_files, lsRequestId());
+    project->Index(working_files, lsRequestId());
   }
 };
 REGISTER_MESSAGE_HANDLER(Handler_CclsFreshenIndex);
diff --git a/src/messages/ccls_inheritance_hierarchy.cc b/src/messages/ccls_inheritance_hierarchy.cc
index bbf255a1..c6fccaff 100644
--- a/src/messages/ccls_inheritance_hierarchy.cc
+++ b/src/messages/ccls_inheritance_hierarchy.cc
@@ -1,6 +1,7 @@
 #include "message_handler.h"
 #include "query_utils.h"
-#include "queue_manager.h"
+#include "pipeline.hh"
+using namespace ccls;
 
 #include <unordered_set>
 
@@ -95,7 +96,7 @@ bool ExpandHelper(MessageHandler* m,
   if (derived) {
     if (levels > 0) {
       for (auto usr : entity.derived) {
-        if (seen.insert(usr).second)
+        if (!seen.insert(usr).second)
           continue;
         Out_CclsInheritanceHierarchy::Entry entry1;
         entry1.id = std::to_string(usr);
@@ -110,7 +111,7 @@ bool ExpandHelper(MessageHandler* m,
   } else {
     if (levels > 0) {
       for (auto usr : def->bases) {
-        if (seen.insert(usr).second)
+        if (!seen.insert(usr).second)
           continue;
         Out_CclsInheritanceHierarchy::Entry entry1;
         entry1.id = std::to_string(usr);
@@ -180,17 +181,15 @@ struct Handler_CclsInheritanceHierarchy
       WorkingFile* wfile =
           working_files->GetFileByFilename(file->def->path);
 
-      for (SymbolRef sym :
-           FindSymbolsAtLocation(wfile, file, params.position)) {
+      for (SymbolRef sym : FindSymbolsAtLocation(wfile, file, params.position))
         if (sym.kind == SymbolKind::Func || sym.kind == SymbolKind::Type) {
           out.result = BuildInitial(sym, params.derived, params.qualified,
                                     params.levels);
           break;
         }
-      }
     }
 
-    QueueManager::WriteStdout(kMethodType, out);
+    pipeline::WriteStdout(kMethodType, out);
   }
 };
 REGISTER_MESSAGE_HANDLER(Handler_CclsInheritanceHierarchy);
diff --git a/src/messages/ccls_member_hierarchy.cc b/src/messages/ccls_member_hierarchy.cc
index dd075c39..2ac6045d 100644
--- a/src/messages/ccls_member_hierarchy.cc
+++ b/src/messages/ccls_member_hierarchy.cc
@@ -1,6 +1,7 @@
 #include "message_handler.h"
+#include "pipeline.hh"
 #include "query_utils.h"
-#include "queue_manager.h"
+using namespace ccls;
 
 #include <unordered_set>
 
@@ -264,7 +265,7 @@ struct Handler_CclsMemberHierarchy
       }
     }
 
-    QueueManager::WriteStdout(kMethodType, out);
+    pipeline::WriteStdout(kMethodType, out);
   }
 };
 REGISTER_MESSAGE_HANDLER(Handler_CclsMemberHierarchy);
diff --git a/src/messages/ccls_random.cc b/src/messages/ccls_random.cc
index 3a32f6ef..382bba34 100644
--- a/src/messages/ccls_random.cc
+++ b/src/messages/ccls_random.cc
@@ -1,6 +1,7 @@
 #include "message_handler.h"
 #include "query_utils.h"
-#include "queue_manager.h"
+#include "pipeline.hh"
+using namespace ccls;
 
 #include <math.h>
 #include <stdlib.h>
@@ -126,7 +127,7 @@ struct Handler_CclsRandom : BaseMessageHandler<In_CclsRandom> {
         break;
       }
     }
-    QueueManager::WriteStdout(kMethodType, out);
+    pipeline::WriteStdout(kMethodType, out);
   }
 };
 REGISTER_MESSAGE_HANDLER(Handler_CclsRandom);
diff --git a/src/messages/ccls_vars.cc b/src/messages/ccls_vars.cc
index 90575b90..31e0c779 100644
--- a/src/messages/ccls_vars.cc
+++ b/src/messages/ccls_vars.cc
@@ -1,6 +1,7 @@
 #include "message_handler.h"
 #include "query_utils.h"
-#include "queue_manager.h"
+#include "pipeline.hh"
+using namespace ccls;
 
 namespace {
 MethodType kMethodType = "$ccls/vars";
@@ -48,7 +49,7 @@ struct Handler_CclsVars : BaseMessageHandler<In_CclsVars> {
           break;
       }
     }
-    QueueManager::WriteStdout(kMethodType, out);
+    pipeline::WriteStdout(kMethodType, out);
   }
 };
 REGISTER_MESSAGE_HANDLER(Handler_CclsVars);
diff --git a/src/messages/initialize.cc b/src/messages/initialize.cc
index d15ba2e2..7a00ca81 100644
--- a/src/messages/initialize.cc
+++ b/src/messages/initialize.cc
@@ -1,4 +1,3 @@
-#include "cache_manager.h"
 #include "diagnostics_engine.h"
 #include "filesystem.hh"
 #include "include_complete.h"
@@ -7,10 +6,10 @@
 #include "pipeline.hh"
 #include "platform.h"
 #include "project.h"
-#include "queue_manager.h"
 #include "serializers/json.h"
 #include "timer.h"
 #include "working_files.h"
+using namespace ccls;
 
 #include <llvm/ADT/Twine.h>
 #include <llvm/Support/Threading.h>
@@ -482,7 +481,7 @@ struct Handler_Initialize : BaseMessageHandler<In_InitializeRequest> {
     Out_InitializeResponse out;
     out.id = request->id;
 
-    QueueManager::WriteStdout(kMethodType, out);
+    pipeline::WriteStdout(kMethodType, out);
 
     // Set project root.
     EnsureEndsInSlash(project_path);
@@ -515,7 +514,7 @@ struct Handler_Initialize : BaseMessageHandler<In_InitializeRequest> {
         g_thread_id = i + 1;
         std::string name = "indexer" + std::to_string(i);
         set_thread_name(name.c_str());
-        Indexer_Main(diag_engine, vfs, project, working_files, waiter);
+        pipeline::Indexer_Main(diag_engine, vfs, project, working_files);
       }).detach();
     }
 
@@ -524,7 +523,7 @@ struct Handler_Initialize : BaseMessageHandler<In_InitializeRequest> {
     include_complete->Rescan();
 
     time.Reset();
-    project->Index(QueueManager::instance(), working_files, request->id);
+    project->Index(working_files, request->id);
     // We need to support multiple concurrent index processes.
     time.ResetAndPrint("[perf] Dispatched initial index requests");
   }
diff --git a/src/messages/shutdown.cc b/src/messages/shutdown.cc
index e16721d4..e06c7281 100644
--- a/src/messages/shutdown.cc
+++ b/src/messages/shutdown.cc
@@ -1,5 +1,6 @@
 #include "message_handler.h"
-#include "queue_manager.h"
+#include "pipeline.hh"
+using namespace ccls;
 
 namespace {
 MethodType kMethodType = "shutdown";
@@ -21,7 +22,7 @@ struct Handler_Shutdown : BaseMessageHandler<In_Shutdown> {
   void Run(In_Shutdown* request) override {
     Out_Shutdown out;
     out.id = request->id;
-    QueueManager::WriteStdout(kMethodType, out);
+    pipeline::WriteStdout(kMethodType, out);
   }
 };
 REGISTER_MESSAGE_HANDLER(Handler_Shutdown);
diff --git a/src/messages/text_document_code_lens.cc b/src/messages/text_document_code_lens.cc
index 2ac395c9..a5b32fb6 100644
--- a/src/messages/text_document_code_lens.cc
+++ b/src/messages/text_document_code_lens.cc
@@ -2,7 +2,8 @@
 #include "lsp_code_action.h"
 #include "message_handler.h"
 #include "query_utils.h"
-#include "queue_manager.h"
+#include "pipeline.hh"
+using namespace ccls;
 
 namespace {
 MethodType kMethodType = "textDocument/codeLens";
@@ -225,7 +226,7 @@ struct Handler_TextDocumentCodeLens
       };
     }
 
-    QueueManager::WriteStdout(kMethodType, out);
+    pipeline::WriteStdout(kMethodType, out);
   }
 };
 REGISTER_MESSAGE_HANDLER(Handler_TextDocumentCodeLens);
diff --git a/src/messages/text_document_completion.cc b/src/messages/text_document_completion.cc
index 1f536a40..39998655 100644
--- a/src/messages/text_document_completion.cc
+++ b/src/messages/text_document_completion.cc
@@ -2,9 +2,10 @@
 #include "fuzzy_match.h"
 #include "include_complete.h"
 #include "message_handler.h"
-#include "queue_manager.h"
+#include "pipeline.hh"
 #include "timer.h"
 #include "working_files.h"
+using namespace ccls;
 
 #include "lex_utils.h"
 
@@ -270,7 +271,7 @@ struct Handler_TextDocumentCompletion : MessageHandler {
     auto write_empty_result = [request]() {
       Out_TextDocumentComplete out;
       out.id = request->id;
-      QueueManager::WriteStdout(kMethodType, out);
+      pipeline::WriteStdout(kMethodType, out);
     };
 
     std::string path = request->params.textDocument.uri.GetPath();
@@ -377,7 +378,7 @@ struct Handler_TextDocumentCompletion : MessageHandler {
         item.textEdit->range.end.character = (int)buffer_line.size();
       }
 
-      QueueManager::WriteStdout(kMethodType, out);
+      pipeline::WriteStdout(kMethodType, out);
     } else {
       ClangCompleteManager::OnComplete callback = std::bind(
           [this, request, is_global_completion, existing_completion,
@@ -389,7 +390,7 @@ struct Handler_TextDocumentCompletion : MessageHandler {
 
             // Emit completion results.
             FilterAndSortCompletionResponse(&out, existing_completion, has_open_paren);
-            QueueManager::WriteStdout(kMethodType, out);
+            pipeline::WriteStdout(kMethodType, out);
 
             // Cache completion results.
             if (!is_cached_result) {
diff --git a/src/messages/text_document_definition.cc b/src/messages/text_document_definition.cc
index 1d7e545a..80aaf9a1 100644
--- a/src/messages/text_document_definition.cc
+++ b/src/messages/text_document_definition.cc
@@ -1,7 +1,8 @@
 #include "lex_utils.h"
 #include "message_handler.h"
+#include "pipeline.hh"
 #include "query_utils.h"
-#include "queue_manager.h"
+using namespace ccls;
 
 #include <ctype.h>
 #include <limits.h>
@@ -173,7 +174,7 @@ struct Handler_TextDocumentDefinition
       }
     }
 
-    QueueManager::WriteStdout(kMethodType, out);
+    pipeline::WriteStdout(kMethodType, out);
   }
 };
 REGISTER_MESSAGE_HANDLER(Handler_TextDocumentDefinition);
diff --git a/src/messages/text_document_did_change.cc b/src/messages/text_document_did_change.cc
index 8072cb95..54ce8b70 100644
--- a/src/messages/text_document_did_change.cc
+++ b/src/messages/text_document_did_change.cc
@@ -1,9 +1,9 @@
-#include "cache_manager.h"
 #include "clang_complete.h"
 #include "message_handler.h"
 #include "project.h"
 #include "working_files.h"
-#include "queue_manager.h"
+#include "pipeline.hh"
+using namespace ccls;
 
 namespace {
 MethodType kMethodType = "textDocument/didChange";
@@ -25,9 +25,7 @@ struct Handler_TextDocumentDidChange
     working_files->OnChange(request->params);
     if (g_config->index.onDidChange) {
       Project::Entry entry = project->FindCompilationEntryForFile(path);
-      QueueManager::instance()->index_request.PushBack(
-          Index_Request(entry.filename, entry.args, true /*is_interactive*/),
-          true);
+      pipeline::Index(entry.filename, entry.args, true);
     }
     clang_complete->NotifyEdit(path);
     clang_complete->DiagnosticsUpdate(
diff --git a/src/messages/text_document_did_close.cc b/src/messages/text_document_did_close.cc
index 6cf1d3fb..e13382d7 100644
--- a/src/messages/text_document_did_close.cc
+++ b/src/messages/text_document_did_close.cc
@@ -1,7 +1,8 @@
 #include "clang_complete.h"
 #include "message_handler.h"
-#include "queue_manager.h"
+#include "pipeline.hh"
 #include "working_files.h"
+using namespace ccls;
 
 namespace {
 MethodType kMethodType = "textDocument/didClose";
@@ -27,7 +28,7 @@ struct Handler_TextDocumentDidClose
     // Clear any diagnostics for the file.
     Out_TextDocumentPublishDiagnostics out;
     out.params.uri = request->params.textDocument.uri;
-    QueueManager::WriteStdout(kMethodType, out);
+    pipeline::WriteStdout(kMethodType, out);
 
     // Remove internal state.
     working_files->OnClose(request->params.textDocument);
diff --git a/src/messages/text_document_did_open.cc b/src/messages/text_document_did_open.cc
index 12c79bdb..0f45b506 100644
--- a/src/messages/text_document_did_open.cc
+++ b/src/messages/text_document_did_open.cc
@@ -1,9 +1,9 @@
-#include "cache_manager.h"
 #include "clang_complete.h"
 #include "include_complete.h"
 #include "message_handler.h"
 #include "project.h"
-#include "queue_manager.h"
+#include "pipeline.hh"
+using namespace ccls;
 #include "timer.h"
 #include "working_files.h"
 
@@ -38,11 +38,9 @@ struct Handler_TextDocumentDidOpen
     const auto& params = request->params;
     std::string path = params.textDocument.uri.GetPath();
 
-    ICacheManager cache;
     WorkingFile* working_file = working_files->OnOpen(params.textDocument);
-    std::optional<std::string> cached_file_contents =
-        cache.LoadCachedFileContents(path);
-    if (cached_file_contents)
+    if (std::optional<std::string> cached_file_contents =
+            pipeline::LoadCachedFileContents(path))
       working_file->SetIndexContent(*cached_file_contents);
 
     QueryFile* file = nullptr;
@@ -60,11 +58,8 @@ struct Handler_TextDocumentDidOpen
     // Submit new index request if it is not a header file.
     if (SourceFileLanguage(path) != LanguageId::Unknown) {
       Project::Entry entry = project->FindCompilationEntryForFile(path);
-      QueueManager::instance()->index_request.PushBack(
-          Index_Request(entry.filename,
-                        params.args.size() ? params.args : entry.args,
-                        true /*is_interactive*/),
-          true /* priority */);
+      pipeline::Index(entry.filename,
+                      params.args.size() ? params.args : entry.args, true);
 
       clang_complete->FlushSession(entry.filename);
     }
diff --git a/src/messages/text_document_did_save.cc b/src/messages/text_document_did_save.cc
index 50835f01..d3c77f06 100644
--- a/src/messages/text_document_did_save.cc
+++ b/src/messages/text_document_did_save.cc
@@ -1,8 +1,8 @@
-#include "cache_manager.h"
 #include "clang_complete.h"
 #include "message_handler.h"
 #include "project.h"
-#include "queue_manager.h"
+#include "pipeline.hh"
+using namespace ccls;
 
 namespace {
 MethodType kMethodType = "textDocument/didSave";
@@ -29,7 +29,8 @@ struct Handler_TextDocumentDidSave
   MethodType GetMethodType() const override { return kMethodType; }
 
   void Run(In_TextDocumentDidSave* request) override {
-    std::string path = request->params.textDocument.uri.GetPath();
+    const auto& params = request->params;
+    std::string path = params.textDocument.uri.GetPath();
 
     // Send out an index request, and copy the current buffer state so we
     // can update the cached index contents when the index is done.
@@ -47,9 +48,7 @@ struct Handler_TextDocumentDidSave
     // TODO: send as priority request
     if (!g_config->index.onDidChange) {
       Project::Entry entry = project->FindCompilationEntryForFile(path);
-      QueueManager::instance()->index_request.PushBack(
-          Index_Request(entry.filename, entry.args, true /*is_interactive*/),
-          true);
+      pipeline::Index(entry.filename, entry.args, true);
     }
 
     clang_complete->NotifySave(path);
diff --git a/src/messages/text_document_document_highlight.cc b/src/messages/text_document_document_highlight.cc
index 643ef859..f7cfc0f1 100644
--- a/src/messages/text_document_document_highlight.cc
+++ b/src/messages/text_document_document_highlight.cc
@@ -1,7 +1,8 @@
 #include "message_handler.h"
+#include "pipeline.hh"
 #include "query_utils.h"
-#include "queue_manager.h"
 #include "symbol.h"
+using namespace ccls;
 
 namespace {
 MethodType kMethodType = "textDocument/documentHighlight";
@@ -61,7 +62,7 @@ struct Handler_TextDocumentDocumentHighlight
       break;
     }
 
-    QueueManager::WriteStdout(kMethodType, out);
+    pipeline::WriteStdout(kMethodType, out);
   }
 };
 REGISTER_MESSAGE_HANDLER(Handler_TextDocumentDocumentHighlight);
diff --git a/src/messages/text_document_document_symbol.cc b/src/messages/text_document_document_symbol.cc
index 29071eb7..959328e3 100644
--- a/src/messages/text_document_document_symbol.cc
+++ b/src/messages/text_document_document_symbol.cc
@@ -1,6 +1,7 @@
 #include "message_handler.h"
+#include "pipeline.hh"
 #include "query_utils.h"
-#include "queue_manager.h"
+using namespace ccls;
 
 namespace {
 MethodType kMethodType = "textDocument/documentSymbol";
@@ -64,7 +65,7 @@ struct Handler_TextDocumentDocumentSymbol
       }
     }
 
-    QueueManager::WriteStdout(kMethodType, out);
+    pipeline::WriteStdout(kMethodType, out);
   }
 };
 REGISTER_MESSAGE_HANDLER(Handler_TextDocumentDocumentSymbol);
diff --git a/src/messages/text_document_hover.cc b/src/messages/text_document_hover.cc
index eacd662b..f3f28218 100644
--- a/src/messages/text_document_hover.cc
+++ b/src/messages/text_document_hover.cc
@@ -1,6 +1,7 @@
 #include "message_handler.h"
+#include "pipeline.hh"
 #include "query_utils.h"
-#include "queue_manager.h"
+using namespace ccls;
 
 namespace {
 MethodType kMethodType = "textDocument/hover";
@@ -99,7 +100,7 @@ struct Handler_TextDocumentHover : BaseMessageHandler<In_TextDocumentHover> {
       }
     }
 
-    QueueManager::WriteStdout(kMethodType, out);
+    pipeline::WriteStdout(kMethodType, out);
   }
 };
 REGISTER_MESSAGE_HANDLER(Handler_TextDocumentHover);
diff --git a/src/messages/text_document_implementation.cc b/src/messages/text_document_implementation.cc
index 6bb5148f..8c10fbac 100644
--- a/src/messages/text_document_implementation.cc
+++ b/src/messages/text_document_implementation.cc
@@ -1,6 +1,7 @@
 #include "message_handler.h"
 #include "query_utils.h"
-#include "queue_manager.h"
+#include "pipeline.hh"
+using namespace ccls;
 
 namespace {
 MethodType kMethodType = "textDocument/implementation";
@@ -41,7 +42,7 @@ struct Handler_TextDocumentImplementation
         break;
       }
     }
-    QueueManager::WriteStdout(kMethodType, out);
+    pipeline::WriteStdout(kMethodType, out);
   }
 };
 REGISTER_MESSAGE_HANDLER(Handler_TextDocumentImplementation);
diff --git a/src/messages/text_document_range_formatting.cc b/src/messages/text_document_range_formatting.cc
index bc860f67..8ffe41f8 100644
--- a/src/messages/text_document_range_formatting.cc
+++ b/src/messages/text_document_range_formatting.cc
@@ -1,7 +1,8 @@
 #include "clang_format.h"
 #include "lex_utils.h"
 #include "message_handler.h"
-#include "queue_manager.h"
+#include "pipeline.hh"
+using namespace ccls;
 #include "working_files.h"
 
 #include <loguru.hpp>
@@ -64,7 +65,7 @@ struct Handler_TextDocumentRangeFormatting
     response.result = {};
 #endif
 
-    QueueManager::WriteStdout(kMethodType, response);
+    pipeline::WriteStdout(kMethodType, response);
   }
 };
 REGISTER_MESSAGE_HANDLER(Handler_TextDocumentRangeFormatting);
diff --git a/src/messages/text_document_references.cc b/src/messages/text_document_references.cc
index dce6e5b7..d8d60f11 100644
--- a/src/messages/text_document_references.cc
+++ b/src/messages/text_document_references.cc
@@ -1,6 +1,7 @@
 #include "message_handler.h"
+#include "pipeline.hh"
 #include "query_utils.h"
-#include "queue_manager.h"
+using namespace ccls;
 
 #include <unordered_set>
 
@@ -135,7 +136,7 @@ struct Handler_TextDocumentReferences
 
     if ((int)out.result.size() >= g_config->xref.maxNum)
       out.result.resize(g_config->xref.maxNum);
-    QueueManager::WriteStdout(kMethodType, out);
+    pipeline::WriteStdout(kMethodType, out);
   }
 };
 REGISTER_MESSAGE_HANDLER(Handler_TextDocumentReferences);
diff --git a/src/messages/text_document_rename.cc b/src/messages/text_document_rename.cc
index a3301998..6e2844bb 100644
--- a/src/messages/text_document_rename.cc
+++ b/src/messages/text_document_rename.cc
@@ -1,6 +1,7 @@
 #include "message_handler.h"
 #include "query_utils.h"
-#include "queue_manager.h"
+#include "pipeline.hh"
+using namespace ccls;
 
 namespace {
 MethodType kMethodType = "textDocument/rename";
@@ -102,7 +103,7 @@ struct Handler_TextDocumentRename : BaseMessageHandler<In_TextDocumentRename> {
       break;
     }
 
-    QueueManager::WriteStdout(kMethodType, out);
+    pipeline::WriteStdout(kMethodType, out);
   }
 };
 REGISTER_MESSAGE_HANDLER(Handler_TextDocumentRename);
diff --git a/src/messages/text_document_signature_help.cc b/src/messages/text_document_signature_help.cc
index c06050ea..608c4037 100644
--- a/src/messages/text_document_signature_help.cc
+++ b/src/messages/text_document_signature_help.cc
@@ -1,6 +1,7 @@
 #include "clang_complete.h"
 #include "message_handler.h"
-#include "queue_manager.h"
+#include "pipeline.hh"
+using namespace ccls;
 #include "timer.h"
 
 #include <stdint.h>
@@ -142,7 +143,7 @@ struct Handler_TextDocumentSignatureHelp : MessageHandler {
           out.result.activeParameter = active_param;
 
           Timer timer;
-          QueueManager::WriteStdout(kMethodType, out);
+          pipeline::WriteStdout(kMethodType, out);
 
           if (!is_cached_result) {
             signature_cache->WithLock([&]() {
diff --git a/src/messages/text_document_type_definition.cc b/src/messages/text_document_type_definition.cc
index 4a31cde2..98a54312 100644
--- a/src/messages/text_document_type_definition.cc
+++ b/src/messages/text_document_type_definition.cc
@@ -1,6 +1,7 @@
 #include "message_handler.h"
+#include "pipeline.hh"
 #include "query_utils.h"
-#include "queue_manager.h"
+using namespace ccls;
 
 namespace {
 MethodType kMethodType = "textDocument/typeDefinition";
@@ -60,7 +61,7 @@ struct Handler_TextDocumentTypeDefinition
       }
     }
 
-    QueueManager::WriteStdout(kMethodType, out);
+    pipeline::WriteStdout(kMethodType, out);
   }
 };
 REGISTER_MESSAGE_HANDLER(Handler_TextDocumentTypeDefinition);
diff --git a/src/messages/workspace_did_change_configuration.cc b/src/messages/workspace_did_change_configuration.cc
index ab33009b..73775d42 100644
--- a/src/messages/workspace_did_change_configuration.cc
+++ b/src/messages/workspace_did_change_configuration.cc
@@ -1,8 +1,8 @@
-#include "cache_manager.h"
 #include "clang_complete.h"
 #include "message_handler.h"
 #include "project.h"
-#include "queue_manager.h"
+#include "pipeline.hh"
+using namespace ccls;
 #include "timer.h"
 #include "working_files.h"
 
@@ -31,7 +31,7 @@ struct Handler_WorkspaceDidChangeConfiguration
                        std::to_string(project->entries.size()) + " files)");
 
     time.Reset();
-    project->Index(QueueManager::instance(), working_files, lsRequestId());
+    project->Index(working_files, lsRequestId());
     time.ResetAndPrint(
         "[perf] Dispatched workspace/didChangeConfiguration index requests");
 
diff --git a/src/messages/workspace_did_change_watched_files.cc b/src/messages/workspace_did_change_watched_files.cc
index 3140a929..f5e81363 100644
--- a/src/messages/workspace_did_change_watched_files.cc
+++ b/src/messages/workspace_did_change_watched_files.cc
@@ -1,9 +1,9 @@
-#include "cache_manager.h"
 #include "clang_complete.h"
 #include "message_handler.h"
 #include "project.h"
-#include "queue_manager.h"
+#include "pipeline.hh"
 #include "working_files.h"
+using namespace ccls;
 
 namespace {
 MethodType kMethodType = "workspace/didChangeWatchedFiles";
@@ -52,15 +52,13 @@ struct Handler_WorkspaceDidChangeWatchedFiles
       switch (event.type) {
         case lsFileChangeType::Created:
         case lsFileChangeType::Changed: {
-          QueueManager::instance()->index_request.PushBack(
-              Index_Request(path, entry.args, is_interactive));
+          pipeline::Index(path, entry.args, is_interactive);
           if (is_interactive)
             clang_complete->NotifySave(path);
           break;
         }
         case lsFileChangeType::Deleted:
-          QueueManager::instance()->index_request.PushBack(
-              Index_Request(path, entry.args, is_interactive));
+          pipeline::Index(path, entry.args, is_interactive);
           break;
       }
     }
diff --git a/src/messages/workspace_execute_command.cc b/src/messages/workspace_execute_command.cc
index 8c1327c1..c2d71c75 100644
--- a/src/messages/workspace_execute_command.cc
+++ b/src/messages/workspace_execute_command.cc
@@ -1,7 +1,8 @@
 #include "lsp_code_action.h"
 #include "message_handler.h"
 #include "query_utils.h"
-#include "queue_manager.h"
+#include "pipeline.hh"
+using namespace ccls;
 
 namespace {
 MethodType kMethodType = "workspace/executeCommand";
@@ -34,7 +35,7 @@ struct Handler_WorkspaceExecuteCommand
       out.result = params.arguments.locations;
     }
 
-    QueueManager::WriteStdout(kMethodType, out);
+    pipeline::WriteStdout(kMethodType, out);
   }
 };
 REGISTER_MESSAGE_HANDLER(Handler_WorkspaceExecuteCommand);
diff --git a/src/messages/workspace_symbol.cc b/src/messages/workspace_symbol.cc
index 77df7fea..d9e88dca 100644
--- a/src/messages/workspace_symbol.cc
+++ b/src/messages/workspace_symbol.cc
@@ -1,8 +1,9 @@
 #include "fuzzy_match.h"
 #include "lex_utils.h"
 #include "message_handler.h"
+#include "pipeline.hh"
 #include "query_utils.h"
-#include "queue_manager.h"
+using namespace ccls;
 
 #include <ctype.h>
 #include <limits.h>
@@ -124,7 +125,7 @@ struct Handler_WorkspaceSymbol : BaseMessageHandler<In_WorkspaceSymbol> {
         out.result.push_back(std::get<0>(entry));
     }
 
-    QueueManager::WriteStdout(kMethodType, out);
+    pipeline::WriteStdout(kMethodType, out);
   }
 };
 REGISTER_MESSAGE_HANDLER(Handler_WorkspaceSymbol);
diff --git a/src/pipeline.cc b/src/pipeline.cc
index b552448f..1b06cca7 100644
--- a/src/pipeline.cc
+++ b/src/pipeline.cc
@@ -1,6 +1,5 @@
 #include "pipeline.hh"
 
-#include "cache_manager.h"
 #include "clang_complete.h"
 #include "config.h"
 #include "diagnostics_engine.h"
@@ -11,18 +10,43 @@
 #include "platform.h"
 #include "project.h"
 #include "query_utils.h"
-#include "queue_manager.h"
+#include "pipeline.hh"
 #include "timer.h"
 
 #include <llvm/ADT/Twine.h>
 #include <llvm/Support/Threading.h>
 using namespace llvm;
 
-#include <chrono>
 #include <thread>
 
+struct Index_Request {
+  std::string path;
+  std::vector<std::string> args;
+  bool is_interactive;
+  lsRequestId id;
+};
+
+struct Index_OnIndexed {
+  IndexUpdate update;
+  PerformanceImportFile perf;
+};
+
+struct Stdout_Request {
+  MethodType method;
+  std::string content;
+};
+
+namespace ccls::pipeline {
 namespace {
 
+MultiQueueWaiter* main_waiter;
+MultiQueueWaiter* indexer_waiter;
+MultiQueueWaiter* stdout_waiter;
+ThreadedQueue<std::unique_ptr<InMessage>>* on_request;
+ThreadedQueue<Index_Request>* index_request;
+ThreadedQueue<Index_OnIndexed>* on_indexed;
+ThreadedQueue<Stdout_Request>* for_stdout;
+
 // Checks if |path| needs to be reparsed. This will modify cached state
 // such that calling this function twice with the same path may return true
 // the first time but will return false the second.
@@ -64,24 +88,57 @@ bool FileNeedsParse(int64_t write_time,
   return false;
 };
 
+std::string AppendSerializationFormat(const std::string& base) {
+  switch (g_config->cacheFormat) {
+    case SerializeFormat::Binary:
+      return base + ".blob";
+    case SerializeFormat::Json:
+      return base + ".json";
+  }
+}
+
+std::string GetCachePath(const std::string& source_file) {
+  std::string cache_file;
+  size_t len = g_config->projectRoot.size();
+  if (StartsWith(source_file, g_config->projectRoot)) {
+    cache_file = EscapeFileName(g_config->projectRoot) +
+                 EscapeFileName(source_file.substr(len));
+  } else {
+    cache_file = '@' + EscapeFileName(g_config->projectRoot) +
+                 EscapeFileName(source_file);
+  }
+
+  return g_config->cacheDirectory + cache_file;
+}
+
+std::unique_ptr<IndexFile> RawCacheLoad(
+    const std::string& path) {
+  std::string cache_path = GetCachePath(path);
+  std::optional<std::string> file_content = ReadContent(cache_path);
+  std::optional<std::string> serialized_indexed_content =
+      ReadContent(AppendSerializationFormat(cache_path));
+  if (!file_content || !serialized_indexed_content)
+    return nullptr;
+
+  return Deserialize(g_config->cacheFormat, path, *serialized_indexed_content,
+                     *file_content, IndexFile::kMajorVersion);
+}
+
 bool Indexer_Parse(DiagnosticsEngine* diag_engine,
                    WorkingFiles* working_files,
                    Project* project,
                    VFS* vfs,
                    ClangIndexer* indexer) {
-  auto* queue = QueueManager::instance();
-  std::optional<Index_Request> opt_request = queue->index_request.TryPopFront();
+  std::optional<Index_Request> opt_request = index_request->TryPopFront();
   if (!opt_request)
     return false;
   auto& request = *opt_request;
-  ICacheManager cache;
 
   // Dummy one to trigger refresh semantic highlight.
   if (request.path.empty()) {
     IndexUpdate dummy;
     dummy.refresh = true;
-    queue->on_indexed.PushBack(
-        Index_OnIndexed(std::move(dummy), PerformanceImportFile()), false);
+    on_indexed->PushBack({std::move(dummy), PerformanceImportFile()}, false);
     return false;
   }
 
@@ -108,7 +165,7 @@ bool Indexer_Parse(DiagnosticsEngine* diag_engine,
     return true;
 
   int reparse; // request.is_interactive;
-  prev = cache.RawCacheLoad(path_to_index);
+  prev = RawCacheLoad(path_to_index);
   if (!prev)
     reparse = 2;
   else {
@@ -132,15 +189,13 @@ bool Indexer_Parse(DiagnosticsEngine* diag_engine,
     auto dependencies = prev->dependencies;
     if (reparse) {
       IndexUpdate update = IndexUpdate::CreateDelta(nullptr, prev.get());
-      queue->on_indexed.PushBack(Index_OnIndexed(std::move(update), perf),
-        request.is_interactive);
+      on_indexed->PushBack({std::move(update), perf}, request.is_interactive);
     }
     for (const auto& dep : dependencies)
       if (vfs->Mark(dep.first().str(), 0, 2)) {
-        prev = cache.RawCacheLoad(dep.first().str());
+        prev = RawCacheLoad(dep.first().str());
         IndexUpdate update = IndexUpdate::CreateDelta(nullptr, prev.get());
-        queue->on_indexed.PushBack(Index_OnIndexed(std::move(update), perf),
-          request.is_interactive);
+        on_indexed->PushBack({std::move(update), perf}, request.is_interactive);
       }
 
     std::lock_guard<std::mutex> lock(vfs->mutex);
@@ -152,7 +207,6 @@ bool Indexer_Parse(DiagnosticsEngine* diag_engine,
 
   LOG_S(INFO) << "parse " << path_to_index;
 
-  std::vector<Index_OnIdMapped> result;
   PerformanceImportFile perf;
   auto indexes = indexer->Index(vfs, path_to_index, entry.args, {}, &perf);
 
@@ -162,7 +216,7 @@ bool Indexer_Parse(DiagnosticsEngine* diag_engine,
       out.id = request.id;
       out.error.code = lsErrorCodes::InternalError;
       out.error.message = "Failed to index " + path_to_index;
-      QueueManager::WriteStdout(kMethodType_Unknown, out);
+      pipeline::WriteStdout(kMethodType_Unknown, out);
     }
     vfs->Reset(path_to_index);
     return true;
@@ -179,12 +233,17 @@ bool Indexer_Parse(DiagnosticsEngine* diag_engine,
     if (!(vfs->Stamp(path, curr->last_write_time) || path == path_to_index))
       continue;
     LOG_S(INFO) << "emit index for " << path;
-    prev = cache.RawCacheLoad(path);
+    prev = RawCacheLoad(path);
 
     // Write current index to disk if requested.
     LOG_S(INFO) << "store index for " << path;
     Timer time;
-    cache.WriteToCache(*curr);
+    {
+      std::string cache_path = GetCachePath(path);
+      WriteToFile(cache_path, curr->file_contents);
+      WriteToFile(AppendSerializationFormat(cache_path),
+                  Serialize(g_config->cacheFormat, *curr));
+    }
     perf.index_save_to_disk = time.ElapsedMicrosecondsAndReset();
 
     vfs->Reset(path_to_index);
@@ -199,8 +258,7 @@ bool Indexer_Parse(DiagnosticsEngine* diag_engine,
     perf.index_make_delta = time.ElapsedMicrosecondsAndReset();
     LOG_S(INFO) << "built index for " << path << " (is_delta=" << !!prev << ")";
 
-    Index_OnIndexed reply(std::move(update), perf);
-    queue->on_indexed.PushBack(std::move(reply), request.is_interactive);
+    on_indexed->PushBack({std::move(update), perf}, request.is_interactive);
   }
 
   return true;
@@ -217,26 +275,34 @@ bool ShouldDisplayMethodTiming(MethodType type) {
 
 }  // namespace
 
+void Init() {
+  main_waiter = new MultiQueueWaiter;
+  on_request = new ThreadedQueue<std::unique_ptr<InMessage>>(main_waiter);
+  on_indexed = new ThreadedQueue<Index_OnIndexed>(main_waiter);
+
+  indexer_waiter = new MultiQueueWaiter;
+  index_request = new ThreadedQueue<Index_Request>(indexer_waiter);
+
+  stdout_waiter = new MultiQueueWaiter;
+  for_stdout = new ThreadedQueue<Stdout_Request>(stdout_waiter);
+}
+
 void Indexer_Main(DiagnosticsEngine* diag_engine,
                   VFS* vfs,
                   Project* project,
-                  WorkingFiles* working_files,
-                  MultiQueueWaiter* waiter) {
-  auto* queue = QueueManager::instance();
+                  WorkingFiles* working_files) {
   // Build one index per-indexer, as building the index acquires a global lock.
   ClangIndexer indexer;
 
   while (true)
     if (!Indexer_Parse(diag_engine, working_files, project, vfs, &indexer))
-      waiter->Wait(&queue->index_request);
+      indexer_waiter->Wait(index_request);
 }
 
-void QueryDb_OnIndexed(QueueManager* queue,
-                       QueryDatabase* db,
-                       SemanticHighlightSymbolCache* semantic_cache,
-                       WorkingFiles* working_files,
-                       Index_OnIndexed* response) {
-
+void Main_OnIndexed(QueryDatabase* db,
+                    SemanticHighlightSymbolCache* semantic_cache,
+                    WorkingFiles* working_files,
+                    Index_OnIndexed* response) {
   if (response->update.refresh) {
     LOG_S(INFO) << "Loaded project. Refresh semantic highlight for all working file.";
     std::lock_guard<std::mutex> lock(working_files->files_mutex);
@@ -257,9 +323,8 @@ void QueryDb_OnIndexed(QueueManager* queue,
   if (response->update.files_def_update) {
     auto& update = *response->update.files_def_update;
     time.ResetAndPrint("apply index for " + update.value.path);
-    WorkingFile* working_file =
-        working_files->GetFileByFilename(update.value.path);
-    if (working_file) {
+    if (WorkingFile* working_file =
+            working_files->GetFileByFilename(update.value.path)) {
       // Update indexed content.
       working_file->SetIndexContent(update.file_content);
 
@@ -275,10 +340,9 @@ void QueryDb_OnIndexed(QueueManager* queue,
   }
 }
 
-void LaunchStdinLoop(std::unordered_map<MethodType, Timer>* request_times) {
+void LaunchStdin(std::unordered_map<MethodType, Timer>* request_times) {
   std::thread([request_times]() {
     set_thread_name("stdin");
-    auto* queue = QueueManager::instance();
     while (true) {
       std::unique_ptr<InMessage> message;
       std::optional<std::string> err =
@@ -295,7 +359,7 @@ void LaunchStdinLoop(std::unordered_map<MethodType, Timer>* request_times) {
             out.id = id;
             out.error.code = lsErrorCodes::InvalidParams;
             out.error.message = std::move(*err);
-            queue->WriteStdout(kMethodType_Unknown, out);
+            WriteStdout(kMethodType_Unknown, out);
           }
         }
         continue;
@@ -305,7 +369,7 @@ void LaunchStdinLoop(std::unordered_map<MethodType, Timer>* request_times) {
       MethodType method_type = message->GetMethodType();
       (*request_times)[method_type] = Timer();
 
-      queue->for_querydb.PushBack(std::move(message));
+      on_request->PushBack(std::move(message));
 
       // If the message was to exit then querydb will take care of the actual
       // exit. Stop reading from stdin since it might be detached.
@@ -315,16 +379,14 @@ void LaunchStdinLoop(std::unordered_map<MethodType, Timer>* request_times) {
   }).detach();
 }
 
-void LaunchStdoutThread(std::unordered_map<MethodType, Timer>* request_times,
-                        MultiQueueWaiter* waiter) {
+void LaunchStdout(std::unordered_map<MethodType, Timer>* request_times) {
   std::thread([=]() {
     set_thread_name("stdout");
-    auto* queue = QueueManager::instance();
 
     while (true) {
-      std::vector<Stdout_Request> messages = queue->for_stdout.DequeueAll();
+      std::vector<Stdout_Request> messages = for_stdout->DequeueAll();
       if (messages.empty()) {
-        waiter->Wait(&queue->for_stdout);
+        stdout_waiter->Wait(for_stdout);
         continue;
       }
 
@@ -341,8 +403,7 @@ void LaunchStdoutThread(std::unordered_map<MethodType, Timer>* request_times,
   }).detach();
 }
 
-void MainLoop(MultiQueueWaiter* querydb_waiter,
-              MultiQueueWaiter* indexer_waiter) {
+void MainLoop() {
   Project project;
   SemanticHighlightSymbolCache semantic_cache;
   WorkingFiles working_files;
@@ -362,7 +423,7 @@ void MainLoop(MultiQueueWaiter* querydb_waiter,
           out.error.message =
               "Dropping completion request; a newer request "
               "has come in that will be serviced instead.";
-          QueueManager::WriteStdout(kMethodType_Unknown, out);
+          pipeline::WriteStdout(kMethodType_Unknown, out);
         }
       });
 
@@ -389,11 +450,8 @@ void MainLoop(MultiQueueWaiter* querydb_waiter,
     handler->signature_cache = signature_cache.get();
   }
 
-  // Run query db main loop.
-  auto* queue = QueueManager::instance();
   while (true) {
-    std::vector<std::unique_ptr<InMessage>> messages =
-        queue->for_querydb.DequeueAll();
+    std::vector<std::unique_ptr<InMessage>> messages = on_request->DequeueAll();
     bool did_work = messages.size();
     for (auto& message : messages) {
       // TODO: Consider using std::unordered_map to lookup the handler
@@ -409,19 +467,40 @@ void MainLoop(MultiQueueWaiter* querydb_waiter,
     }
 
     for (int i = 80; i--;) {
-      std::optional<Index_OnIndexed> response = queue->on_indexed.TryPopFront();
+      std::optional<Index_OnIndexed> response = on_indexed->TryPopFront();
       if (!response)
         break;
       did_work = true;
-      QueryDb_OnIndexed(queue, &db, &semantic_cache, &working_files, &*response);
+      Main_OnIndexed(&db, &semantic_cache, &working_files, &*response);
     }
 
     // Cleanup and free any unused memory.
     FreeUnusedMemory();
 
-    if (!did_work) {
-      auto* queue = QueueManager::instance();
-      querydb_waiter->Wait(&queue->on_indexed, &queue->for_querydb);
-    }
+    if (!did_work)
+      main_waiter->Wait(on_indexed, on_request);
   }
 }
+
+void Index(const std::string& path,
+           const std::vector<std::string>& args,
+           bool interactive,
+           lsRequestId id) {
+  index_request->PushBack({path, args, interactive, id}, interactive);
+}
+
+std::optional<std::string> LoadCachedFileContents(const std::string& path) {
+  return ReadContent(GetCachePath(path));
+}
+
+void WriteStdout(MethodType method, lsBaseOutMessage& response) {
+  std::ostringstream sstream;
+  response.Write(sstream);
+
+  Stdout_Request out;
+  out.content = sstream.str();
+  out.method = method;
+  for_stdout->PushBack(std::move(out));
+}
+
+}
diff --git a/src/pipeline.hh b/src/pipeline.hh
index 87076be9..760ac190 100644
--- a/src/pipeline.hh
+++ b/src/pipeline.hh
@@ -1,28 +1,35 @@
 #pragma once
 
-#include "queue_manager.h"
+#include "method.h"
+#include "query.h"
 #include "timer.h"
 
-#include <atomic>
+#include <string>
 #include <unordered_map>
+#include <vector>
 
-struct ClangTranslationUnit;
 class DiagnosticsEngine;
 struct VFS;
-struct ICacheManager;
 struct Project;
-struct QueryDatabase;
-struct SemanticHighlightSymbolCache;
 struct WorkingFiles;
+struct lsBaseOutMessage;
 
+namespace ccls::pipeline {
+
+void Init();
+void LaunchStdin(std::unordered_map<MethodType, Timer>* request_times);
+void LaunchStdout(std::unordered_map<MethodType, Timer>* request_times);
 void Indexer_Main(DiagnosticsEngine* diag_engine,
                   VFS* vfs,
                   Project* project,
-                  WorkingFiles* working_files,
-                  MultiQueueWaiter* waiter);
+                  WorkingFiles* working_files);
+void MainLoop();
 
-void LaunchStdinLoop(std::unordered_map<MethodType, Timer>* request_times);
-void LaunchStdoutThread(std::unordered_map<MethodType, Timer>* request_times,
-                        MultiQueueWaiter* waiter);
-void MainLoop(MultiQueueWaiter* querydb_waiter,
-              MultiQueueWaiter* indexer_waiter);
+void Index(const std::string& path,
+           const std::vector<std::string>& args,
+           bool is_interactive,
+           lsRequestId id = {});
+
+std::optional<std::string> LoadCachedFileContents(const std::string& path);
+void WriteStdout(MethodType method, lsBaseOutMessage& response);
+}
diff --git a/src/port.cc b/src/port.cc
deleted file mode 100644
index d48df06a..00000000
--- a/src/port.cc
+++ /dev/null
@@ -1,10 +0,0 @@
-#include "port.h"
-
-#include <stdio.h>
-#include <stdlib.h>
-
-void ccls_unreachable_internal(const char* msg, const char* file, int line) {
-  fprintf(stderr, "unreachable %s:%d %s\n", file, line, msg);
-  CCLS_BUILTIN_UNREACHABLE;
-  abort();
-}
diff --git a/src/port.h b/src/port.h
deleted file mode 100644
index da3da313..00000000
--- a/src/port.h
+++ /dev/null
@@ -1,34 +0,0 @@
-#pragma once
-
-#ifndef __has_builtin
-#define __has_builtin(x) 0
-#endif
-
-#if defined(__GNUC__)
-#define ATTRIBUTE_UNUSED __attribute__((unused))
-#else
-#define ATTRIBUTE_UNUSED
-#endif
-
-#ifdef __clang__
-#define GUARDED_BY(x)  __attribute__((guarded_by(x)))
-#else
-#define GUARDED_BY(x)
-#endif
-
-// TODO GCC
-#if __has_builtin(__builtin_unreachable)
-#define CCLS_BUILTIN_UNREACHABLE __builtin_unreachable()
-#elif defined(_MSC_VER)
-#define CCLS_BUILTIN_UNREACHABLE __assume(false)
-#else
-#define CCLS_BUILTIN_UNREACHABLE
-#endif
-
-void ccls_unreachable_internal(const char* msg, const char* file, int line);
-#ifndef NDEBUG
-#define CCLS_UNREACHABLE(msg) \
-  ccls_unreachable_internal(msg, __FILE__, __LINE__)
-#else
-#define CCLS_UNREACHABLE(msg)
-#endif
diff --git a/src/project.cc b/src/project.cc
index 44682d98..90abbb8e 100644
--- a/src/project.cc
+++ b/src/project.cc
@@ -1,17 +1,17 @@
 #include "project.h"
 
-#include "cache_manager.h"
 #include "clang_utils.h"
 #include "filesystem.hh"
 #include "language.h"
 #include "log.hh"
 #include "match.h"
 #include "platform.h"
-#include "queue_manager.h"
+#include "pipeline.hh"
 #include "serializers/json.h"
 #include "timer.h"
 #include "utils.h"
 #include "working_files.h"
+using namespace ccls;
 
 #include <clang/Driver/Options.h>
 #include <llvm/ADT/ArrayRef.h>
@@ -454,17 +454,15 @@ void Project::ForAllFilteredFiles(
   }
 }
 
-void Project::Index(QueueManager* queue,
-                    WorkingFiles* wfiles,
+void Project::Index(WorkingFiles* wfiles,
                     lsRequestId id) {
   ForAllFilteredFiles([&](int i, const Project::Entry& entry) {
     bool is_interactive = wfiles->GetFileByFilename(entry.filename) != nullptr;
-    queue->index_request.PushBack(
-        Index_Request(entry.filename, entry.args, is_interactive, id));
+    pipeline::Index(entry.filename, entry.args, is_interactive, id);
   });
   // Dummy request to indicate that project is loaded and
   // trigger refreshing semantic highlight for all working files.
-  queue->index_request.PushBack(Index_Request("", {}, false));
+  pipeline::Index("", {}, false);
 }
 
 TEST_SUITE("Project") {
diff --git a/src/project.h b/src/project.h
index 4b5220b9..d6d3f396 100644
--- a/src/project.h
+++ b/src/project.h
@@ -5,12 +5,10 @@
 
 #include <functional>
 #include <mutex>
-#include <optional>
 #include <string>
 #include <unordered_map>
 #include <vector>
 
-class QueueManager;
 struct WorkingFiles;
 
 struct Project {
@@ -29,7 +27,7 @@ struct Project {
 
   std::vector<Entry> entries;
   std::mutex mutex_;
-  std::unordered_map<std::string, int> absolute_path_to_entry_index_ GUARDED_BY(mutex_);
+  std::unordered_map<std::string, int> absolute_path_to_entry_index_;
 
   // Loads a project for the given |directory|.
   //
@@ -58,5 +56,5 @@ struct Project {
   void ForAllFilteredFiles(
       std::function<void(int i, const Entry& entry)> action);
 
-  void Index(QueueManager* queue, WorkingFiles* wfiles, lsRequestId id);
+  void Index(WorkingFiles* wfiles, lsRequestId id);
 };
diff --git a/src/query_utils.cc b/src/query_utils.cc
index 9f801ced..04031ded 100644
--- a/src/query_utils.cc
+++ b/src/query_utils.cc
@@ -1,6 +1,6 @@
 #include "query_utils.h"
 
-#include "queue_manager.h"
+#include "pipeline.hh"
 
 #include <limits.h>
 #include <unordered_set>
diff --git a/src/queue_manager.cc b/src/queue_manager.cc
deleted file mode 100644
index 623c72df..00000000
--- a/src/queue_manager.cc
+++ /dev/null
@@ -1,46 +0,0 @@
-#include "queue_manager.h"
-
-#include "cache_manager.h"
-#include "lsp.h"
-#include "query.h"
-
-#include <sstream>
-
-Index_Request::Index_Request(const std::string& path,
-                             const std::vector<std::string>& args,
-                             bool is_interactive,
-                             lsRequestId id)
-    : path(path), args(args), is_interactive(is_interactive), id(id) {}
-
-Index_OnIndexed::Index_OnIndexed(IndexUpdate&& update,
-                                 PerformanceImportFile perf)
-    : update(std::move(update)), perf(perf) {}
-
-std::unique_ptr<QueueManager> QueueManager::instance_;
-
-// static
-void QueueManager::Init(MultiQueueWaiter* querydb_waiter,
-                        MultiQueueWaiter* indexer_waiter,
-                        MultiQueueWaiter* stdout_waiter) {
-  instance_ = std::unique_ptr<QueueManager>(
-      new QueueManager(querydb_waiter, indexer_waiter, stdout_waiter));
-}
-
-// static
-void QueueManager::WriteStdout(MethodType method, lsBaseOutMessage& response) {
-  std::ostringstream sstream;
-  response.Write(sstream);
-
-  Stdout_Request out;
-  out.content = sstream.str();
-  out.method = method;
-  instance()->for_stdout.PushBack(std::move(out));
-}
-
-QueueManager::QueueManager(MultiQueueWaiter* querydb_waiter,
-                           MultiQueueWaiter* indexer_waiter,
-                           MultiQueueWaiter* stdout_waiter)
-    : for_stdout(stdout_waiter),
-      for_querydb(querydb_waiter),
-      on_indexed(querydb_waiter),
-      index_request(indexer_waiter) {}
diff --git a/src/queue_manager.h b/src/queue_manager.h
deleted file mode 100644
index 13ee57b4..00000000
--- a/src/queue_manager.h
+++ /dev/null
@@ -1,84 +0,0 @@
-#pragma once
-
-#include "method.h"
-#include "query.h"
-#include "threaded_queue.h"
-
-#include <memory>
-
-struct ICacheManager;
-struct lsBaseOutMessage;
-
-struct Stdout_Request {
-  MethodType method;
-  std::string content;
-};
-
-struct Index_Request {
-  std::string path;
-  // TODO: make |args| a string that is parsed lazily.
-  std::vector<std::string> args;
-  bool is_interactive;
-  lsRequestId id;
-
-  Index_Request(const std::string& path,
-                const std::vector<std::string>& args,
-                bool is_interactive,
-                lsRequestId id = {});
-};
-
-struct Index_OnIdMapped {
-  std::shared_ptr<ICacheManager> cache_manager;
-  std::unique_ptr<IndexFile> previous;
-  std::unique_ptr<IndexFile> current;
-
-  PerformanceImportFile perf;
-  bool is_interactive;
-  bool write_to_disk;
-
-  Index_OnIdMapped(const std::shared_ptr<ICacheManager>& cache_manager,
-                   std::unique_ptr<IndexFile> previous,
-                   std::unique_ptr<IndexFile> current,
-                   PerformanceImportFile perf,
-                   bool is_interactive,
-                   bool write_to_disk)
-      : cache_manager(cache_manager),
-        previous(std::move(previous)),
-        current(std::move(current)),
-        perf(perf),
-        is_interactive(is_interactive),
-        write_to_disk(write_to_disk) {}
-};
-
-struct Index_OnIndexed {
-  IndexUpdate update;
-  PerformanceImportFile perf;
-
-  Index_OnIndexed(IndexUpdate&& update, PerformanceImportFile perf);
-};
-
-class QueueManager {
-  static std::unique_ptr<QueueManager> instance_;
-
- public:
-  static QueueManager* instance() { return instance_.get(); }
-  static void Init(MultiQueueWaiter* querydb_waiter,
-                   MultiQueueWaiter* indexer_waiter,
-                   MultiQueueWaiter* stdout_waiter);
-  static void WriteStdout(MethodType method, lsBaseOutMessage& response);
-
-  // Messages received by "stdout" thread.
-  ThreadedQueue<Stdout_Request> for_stdout;
-
-  // Runs on querydb thread.
-  ThreadedQueue<std::unique_ptr<InMessage>> for_querydb;
-  ThreadedQueue<Index_OnIndexed> on_indexed;
-
-  // Runs on indexer threads.
-  ThreadedQueue<Index_Request> index_request;
-
- private:
-  explicit QueueManager(MultiQueueWaiter* querydb_waiter,
-                        MultiQueueWaiter* indexer_waiter,
-                        MultiQueueWaiter* stdout_waiter);
-};
diff --git a/src/serializer.h b/src/serializer.h
index cc296c79..28f28481 100644
--- a/src/serializer.h
+++ b/src/serializer.h
@@ -2,7 +2,8 @@
 
 #include "maybe.h"
 #include "nt_string.h"
-#include "port.h"
+
+#include <llvm/Support/Compiler.h>
 
 #include <macro_map.h>
 
@@ -83,15 +84,15 @@ struct IndexFile;
 
 #define MAKE_REFLECT_TYPE_PROXY(type_name) \
   MAKE_REFLECT_TYPE_PROXY2(type_name, std::underlying_type_t<type_name>)
-#define MAKE_REFLECT_TYPE_PROXY2(type, as_type)                        \
-  ATTRIBUTE_UNUSED inline void Reflect(Reader& visitor, type& value) { \
-    as_type value0;                                                    \
-    ::Reflect(visitor, value0);                                        \
-    value = static_cast<type>(value0);                                 \
-  }                                                                    \
-  ATTRIBUTE_UNUSED inline void Reflect(Writer& visitor, type& value) { \
-    auto value0 = static_cast<as_type>(value);                         \
-    ::Reflect(visitor, value0);                                        \
+#define MAKE_REFLECT_TYPE_PROXY2(type, as_type)                             \
+  LLVM_ATTRIBUTE_UNUSED inline void Reflect(Reader& visitor, type& value) { \
+    as_type value0;                                                         \
+    ::Reflect(visitor, value0);                                             \
+    value = static_cast<type>(value0);                                      \
+  }                                                                         \
+  LLVM_ATTRIBUTE_UNUSED inline void Reflect(Writer& visitor, type& value) { \
+    auto value0 = static_cast<as_type>(value);                              \
+    ::Reflect(visitor, value0);                                             \
   }
 
 #define _MAPPABLE_REFLECT_MEMBER(name) REFLECT_MEMBER(name);
diff --git a/src/test.cc b/src/test.cc
index 00dec826..e9b5d8b3 100644
--- a/src/test.cc
+++ b/src/test.cc
@@ -284,8 +284,6 @@ bool RunIndexTests(const std::string& filter_path, bool enable_update) {
                              &all_expected_output);
 
         // Build flags.
-        if (!AnyStartsWith(flags, "-x"))
-          flags.push_back("-xc++");
         flags.push_back("-resource-dir=" + GetDefaultResourceDirectory());
         flags.push_back(path);
 
diff --git a/src/threaded_queue.h b/src/threaded_queue.h
index 93f1ccf1..6e3bc9d7 100644
--- a/src/threaded_queue.h
+++ b/src/threaded_queue.h
@@ -94,26 +94,6 @@ struct ThreadedQueue : public BaseThreadQueue {
     Push<&std::deque<T>::push_back>(std::move(t), priority);
   }
 
-  // Add a set of elements to the queue.
-  void EnqueueAll(std::vector<T>&& elements, bool priority = false) {
-    if (elements.empty())
-      return;
-
-    std::lock_guard<std::mutex> lock(mutex_);
-
-    total_count_ += elements.size();
-
-    for (T& element : elements) {
-      if (priority)
-        priority_.push_back(std::move(element));
-      else
-        queue_.push_back(std::move(element));
-    }
-    elements.clear();
-
-    waiter_->cv.notify_all();
-  }
-
   // Return all elements in the queue.
   std::vector<T> DequeueAll() {
     std::lock_guard<std::mutex> lock(mutex_);
diff --git a/src/utils.cc b/src/utils.cc
index cc448476..68de5189 100644
--- a/src/utils.cc
+++ b/src/utils.cc
@@ -48,15 +48,6 @@ bool StartsWith(std::string_view s, std::string_view prefix) {
          std::equal(prefix.begin(), prefix.end(), s.begin());
 }
 
-bool AnyStartsWith(const std::vector<std::string>& xs,
-                   std::string_view prefix) {
-  return std::any_of(xs.begin(), xs.end(), std::bind(StartsWith, _1, prefix));
-}
-
-bool StartsWithAny(std::string_view s, const std::vector<std::string>& ps) {
-  return std::any_of(ps.begin(), ps.end(), std::bind(StartsWith, s, _1));
-}
-
 bool EndsWithAny(std::string_view s, const std::vector<std::string>& ss) {
   return std::any_of(ss.begin(), ss.end(), std::bind(EndsWith, s, _1));
 }
diff --git a/src/utils.h b/src/utils.h
index 4258ae49..b1febec3 100644
--- a/src/utils.h
+++ b/src/utils.h
@@ -17,8 +17,6 @@ uint64_t HashUsr(std::string_view s);
 // Returns true if |value| starts/ends with |start| or |ending|.
 bool StartsWith(std::string_view value, std::string_view start);
 bool EndsWith(std::string_view value, std::string_view ending);
-bool AnyStartsWith(const std::vector<std::string>& xs, std::string_view prefix);
-bool StartsWithAny(std::string_view s, const std::vector<std::string>& ps);
 bool EndsWithAny(std::string_view s, const std::vector<std::string>& ss);
 bool FindAnyPartial(const std::string& value,
                     const std::vector<std::string>& values);