From 640f548e7c75ae8fcedab7d67e9cc004cf9dbf4b Mon Sep 17 00:00:00 2001
From: Fangrui Song <i@maskray.me>
Date: Sat, 10 Mar 2018 15:40:27 -0800
Subject: [PATCH] Use std::index_sequence and std::make_unique

---
 src/clang_complete.cc                  |  4 ++--
 src/clang_translation_unit.cc          |  2 +-
 src/command_line.cc                    | 11 ++++-----
 src/diagnostics_engine.cc              |  2 +-
 src/file_consumer.cc                   |  2 +-
 src/iindexer.cc                        |  8 +++----
 src/import_pipeline.cc                 |  9 ++++----
 src/include_complete.cc                |  2 +-
 src/lsp.h                              |  2 +-
 src/messages/initialize.cc             |  2 ++
 src/queue_manager.cc                   | 18 +++++----------
 src/queue_manager.h                    | 17 +++++++-------
 src/semantic_highlight_symbol_cache.cc |  2 +-
 src/serializer.cc                      |  4 ++--
 src/task.cc                            |  4 ++--
 src/threaded_queue.h                   | 32 ++++++--------------------
 src/utils.h                            |  8 -------
 src/working_files.cc                   |  2 +-
 18 files changed, 50 insertions(+), 81 deletions(-)

diff --git a/src/clang_complete.cc b/src/clang_complete.cc
index fbb3b136..0eec9a71 100644
--- a/src/clang_complete.cc
+++ b/src/clang_complete.cc
@@ -689,7 +689,7 @@ void ClangCompleteManager::CodeComplete(
     const lsRequestId& id,
     const lsTextDocumentPositionParams& completion_location,
     const OnComplete& on_complete) {
-  completion_request_.PushBack(MakeUnique<CompletionRequest>(
+  completion_request_.PushBack(std::make_unique<CompletionRequest>(
       id, completion_location.textDocument, completion_location.position,
       on_complete, false));
 }
@@ -698,7 +698,7 @@ void ClangCompleteManager::DiagnosticsUpdate(
     const lsRequestId& id,
     const lsTextDocumentIdentifier& document) {
   completion_request_.PushBack(
-      MakeUnique<CompletionRequest>(id, document, true));
+      std::make_unique<CompletionRequest>(id, document, true));
 }
 
 void ClangCompleteManager::NotifyView(const std::string& filename) {
diff --git a/src/clang_translation_unit.cc b/src/clang_translation_unit.cc
index 350df886..52639c98 100644
--- a/src/clang_translation_unit.cc
+++ b/src/clang_translation_unit.cc
@@ -98,7 +98,7 @@ std::unique_ptr<ClangTranslationUnit> ClangTranslationUnit::Create(
 
   switch (error_code) {
     case CXError_Success:
-      return MakeUnique<ClangTranslationUnit>(cx_tu);
+      return std::make_unique<ClangTranslationUnit>(cx_tu);
     case CXError_Failure:
       LOG_S(ERROR) << "libclang generic failure for " << filepath << ". "
                    << make_msg();
diff --git a/src/command_line.cc b/src/command_line.cc
index 5e58227a..717ba3af 100644
--- a/src/command_line.cc
+++ b/src/command_line.cc
@@ -203,9 +203,9 @@ void RunQueryDbThread(const std::string& bin_name,
       });
 
   IncludeComplete include_complete(config, &project);
-  auto global_code_complete_cache = MakeUnique<CodeCompleteCache>();
-  auto non_global_code_complete_cache = MakeUnique<CodeCompleteCache>();
-  auto signature_cache = MakeUnique<CodeCompleteCache>();
+  auto global_code_complete_cache = std::make_unique<CodeCompleteCache>();
+  auto non_global_code_complete_cache = std::make_unique<CodeCompleteCache>();
+  auto signature_cache = std::make_unique<CodeCompleteCache>();
   ImportManager import_manager;
   ImportPipelineStatus import_pipeline_status;
   TimestampManager timestamp_manager;
@@ -423,8 +423,7 @@ int main(int argc, char** argv) {
   loguru::init(argc, argv);
 
   MultiQueueWaiter querydb_waiter, indexer_waiter, stdout_waiter;
-  QueueManager::CreateInstance(&querydb_waiter, &indexer_waiter,
-                               &stdout_waiter);
+  QueueManager::Init(&querydb_waiter, &indexer_waiter, &stdout_waiter);
 
   PlatformInit();
   IndexInit();
@@ -489,7 +488,7 @@ int main(int argc, char** argv) {
     }
 
     // std::cerr << "Running language server" << std::endl;
-    auto config = MakeUnique<Config>();
+    auto config = std::make_unique<Config>();
     LanguageServerMain(argv[0], config.get(), &querydb_waiter, &indexer_waiter,
                        &stdout_waiter);
   }
diff --git a/src/diagnostics_engine.cc b/src/diagnostics_engine.cc
index 199a1aae..8d66325f 100644
--- a/src/diagnostics_engine.cc
+++ b/src/diagnostics_engine.cc
@@ -6,7 +6,7 @@
 
 void DiagnosticsEngine::Init(Config* config) {
   frequencyMs_ = config->diagnostics.frequencyMs;
-  match_ = MakeUnique<GroupMatch>(config->diagnostics.whitelist,
+  match_ = std::make_unique<GroupMatch>(config->diagnostics.whitelist,
                                   config->diagnostics.blacklist);
 }
 
diff --git a/src/file_consumer.cc b/src/file_consumer.cc
index 779895e2..13042d79 100644
--- a/src/file_consumer.cc
+++ b/src/file_consumer.cc
@@ -84,7 +84,7 @@ IndexFile* FileConsumer::TryConsumeFile(CXFile file,
 
   // Build IndexFile instance.
   *is_first_ownership = true;
-  local_[file_id] = MakeUnique<IndexFile>(file_name, *contents);
+  local_[file_id] = std::make_unique<IndexFile>(file_name, *contents);
   return local_[file_id].get();
 }
 
diff --git a/src/iindexer.cc b/src/iindexer.cc
index befed64d..e0758410 100644
--- a/src/iindexer.cc
+++ b/src/iindexer.cc
@@ -30,15 +30,15 @@ struct ClangIndexer : IIndexer {
 struct TestIndexer : IIndexer {
   static std::unique_ptr<TestIndexer> FromEntries(
       const std::vector<TestEntry>& entries) {
-    auto result = MakeUnique<TestIndexer>();
+    auto result = std::make_unique<TestIndexer>();
 
     for (const TestEntry& entry : entries) {
       std::vector<std::unique_ptr<IndexFile>> indexes;
 
       if (entry.num_indexes > 0)
-        indexes.push_back(MakeUnique<IndexFile>(entry.path, "<empty>"));
+        indexes.push_back(std::make_unique<IndexFile>(entry.path, "<empty>"));
       for (int i = 1; i < entry.num_indexes; ++i) {
-        indexes.push_back(MakeUnique<IndexFile>(
+        indexes.push_back(std::make_unique<IndexFile>(
             entry.path + "_extra_" + std::to_string(i) + ".h", "<empty>"));
       }
 
@@ -82,7 +82,7 @@ IIndexer::TestEntry::TestEntry(const std::string& path, int num_indexes)
 
 // static
 std::unique_ptr<IIndexer> IIndexer::MakeClangIndexer() {
-  return MakeUnique<ClangIndexer>();
+  return std::make_unique<ClangIndexer>();
 }
 
 // static
diff --git a/src/import_pipeline.cc b/src/import_pipeline.cc
index f02fbb8a..dc84f642 100644
--- a/src/import_pipeline.cc
+++ b/src/import_pipeline.cc
@@ -677,8 +677,8 @@ void QueryDb_DoIdMap(QueueManager* queue,
     if (!file)
       return nullptr;
 
-    auto id_map = MakeUnique<IdMap>(db, file->id_cache);
-    return MakeUnique<Index_OnIdMapped::File>(std::move(file),
+    auto id_map = std::make_unique<IdMap>(db, file->id_cache);
+    return std::make_unique<Index_OnIdMapped::File>(std::move(file),
                                               std::move(id_map));
   };
   response.current = make_map(std::move(request->current));
@@ -763,8 +763,7 @@ bool QueryDb_ImportMain(Config* config,
 TEST_SUITE("ImportPipeline") {
   struct Fixture {
     Fixture() {
-      QueueManager::CreateInstance(&querydb_waiter, &indexer_waiter,
-                                   &stdout_waiter);
+      QueueManager::Init(&querydb_waiter, &indexer_waiter, &stdout_waiter);
 
       queue = QueueManager::instance();
       cache_manager = ICacheManager::MakeFake({});
@@ -810,7 +809,7 @@ TEST_SUITE("ImportPipeline") {
                      const std::vector<std::string>& new_args = {}) {
       std::unique_ptr<IndexFile> opt_previous_index;
       if (!old_args.empty()) {
-        opt_previous_index = MakeUnique<IndexFile>("---.cc", "<empty>");
+        opt_previous_index = std::make_unique<IndexFile>("---.cc", "<empty>");
         opt_previous_index->args = old_args;
       }
       optional<std::string> from;
diff --git a/src/include_complete.cc b/src/include_complete.cc
index c6116853..9f4476c0 100644
--- a/src/include_complete.cc
+++ b/src/include_complete.cc
@@ -112,7 +112,7 @@ void IncludeComplete::Rescan() {
 
   if (!match_ && (!config_->completion.includeWhitelist.empty() ||
                   !config_->completion.includeBlacklist.empty()))
-    match_ = MakeUnique<GroupMatch>(config_->completion.includeWhitelist,
+    match_ = std::make_unique<GroupMatch>(config_->completion.includeWhitelist,
                                     config_->completion.includeBlacklist);
 
   is_scanning = true;
diff --git a/src/lsp.h b/src/lsp.h
index feca5923..b44024ce 100644
--- a/src/lsp.h
+++ b/src/lsp.h
@@ -47,7 +47,7 @@ struct MessageRegistryRegister {
     std::string method_name = IpcIdToString(T::kIpcId);
     MessageRegistry::instance()->allocators[method_name] =
         [](Reader& visitor, std::unique_ptr<BaseIpcMessage>* message) {
-          *message = MakeUnique<T>();
+          *message = std::make_unique<T>();
           // Reflect may throw and *message will be partially deserialized.
           Reflect(visitor, static_cast<T&>(**message));
         };
diff --git a/src/messages/initialize.cc b/src/messages/initialize.cc
index 2b8453af..e7b822f8 100644
--- a/src/messages/initialize.cc
+++ b/src/messages/initialize.cc
@@ -9,12 +9,14 @@
 #include "semantic_highlight_symbol_cache.h"
 #include "serializers/json.h"
 #include "timer.h"
+#include "work_thread.h"
 #include "working_files.h"
 
 #include <loguru.hpp>
 
 #include <iostream>
 #include <stdexcept>
+#include <thread>
 
 // TODO Cleanup global variables
 extern std::string g_init_options;
diff --git a/src/queue_manager.cc b/src/queue_manager.cc
index 60d6e52f..c3a24cfd 100644
--- a/src/queue_manager.cc
+++ b/src/queue_manager.cc
@@ -52,20 +52,14 @@ Index_OnIndexed::Index_OnIndexed(IndexUpdate&& update,
                                  PerformanceImportFile perf)
     : update(std::move(update)), perf(perf) {}
 
-QueueManager* QueueManager::instance_ = nullptr;
+std::unique_ptr<QueueManager> QueueManager::instance_;
 
 // static
-QueueManager* QueueManager::instance() {
-  return instance_;
-}
-
-// static
-void QueueManager::CreateInstance(MultiQueueWaiter* querydb_waiter,
-                                  MultiQueueWaiter* indexer_waiter,
-                                  MultiQueueWaiter* stdout_waiter) {
-  if (instance_)
-    delete instance_;
-  instance_ = new QueueManager(querydb_waiter, indexer_waiter, stdout_waiter);
+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
diff --git a/src/queue_manager.h b/src/queue_manager.h
index 67ea61ee..46312d54 100644
--- a/src/queue_manager.h
+++ b/src/queue_manager.h
@@ -78,16 +78,19 @@ struct Index_OnIndexed {
   Index_OnIndexed(IndexUpdate&& update, PerformanceImportFile perf);
 };
 
-struct QueueManager {
-  static QueueManager* instance();
-  static void CreateInstance(MultiQueueWaiter* querydb_waiter,
-                             MultiQueueWaiter* indexer_waiter,
-                             MultiQueueWaiter* stdout_waiter);
+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(IpcId id, lsBaseOutMessage& response);
 
   bool HasWork();
 
-  // Runs on stdout thread.
+  // Messages received by "stdout" thread.
   ThreadedQueue<Stdout_Request> for_stdout;
 
   // Runs on querydb thread.
@@ -107,6 +110,4 @@ struct QueueManager {
   explicit QueueManager(MultiQueueWaiter* querydb_waiter,
                         MultiQueueWaiter* indexer_waiter,
                         MultiQueueWaiter* stdout_waiter);
-
-  static QueueManager* instance_;
 };
diff --git a/src/semantic_highlight_symbol_cache.cc b/src/semantic_highlight_symbol_cache.cc
index f3a55790..5992b5d4 100644
--- a/src/semantic_highlight_symbol_cache.cc
+++ b/src/semantic_highlight_symbol_cache.cc
@@ -61,7 +61,7 @@ SemanticHighlightSymbolCache::SemanticHighlightSymbolCache()
     : cache_(kCacheSize) {}
 
 void SemanticHighlightSymbolCache::Init(Config* config) {
-  match_ = MakeUnique<GroupMatch>(config->highlight.whitelist,
+  match_ = std::make_unique<GroupMatch>(config->highlight.whitelist,
                                   config->highlight.blacklist);
 }
 
diff --git a/src/serializer.cc b/src/serializer.cc
index b03ce1eb..07db20de 100644
--- a/src/serializer.cc
+++ b/src/serializer.cc
@@ -383,7 +383,7 @@ std::unique_ptr<IndexFile> Deserialize(
       if (reader.HasParseError())
         return nullptr;
 
-      file = MakeUnique<IndexFile>(path, file_content);
+      file = std::make_unique<IndexFile>(path, file_content);
       JsonReader json_reader{&reader};
       try {
         Reflect(json_reader, *file);
@@ -405,7 +405,7 @@ std::unique_ptr<IndexFile> Deserialize(
         memcpy(upk.buffer(), serialized_index_content.data(),
                serialized_index_content.size());
         upk.buffer_consumed(serialized_index_content.size());
-        file = MakeUnique<IndexFile>(path, file_content);
+        file = std::make_unique<IndexFile>(path, file_content);
         MessagePackReader reader(&upk);
         Reflect(reader, major);
         Reflect(reader, minor);
diff --git a/src/task.cc b/src/task.cc
index 81413314..b26f7b60 100644
--- a/src/task.cc
+++ b/src/task.cc
@@ -6,8 +6,8 @@
 #include <doctest/doctest.h>
 
 TaskManager::TaskManager() {
-  pending_tasks_[TaskThread::Indexer] = MakeUnique<TaskQueue>();
-  pending_tasks_[TaskThread::QueryDb] = MakeUnique<TaskQueue>();
+  pending_tasks_[TaskThread::Indexer] = std::make_unique<TaskQueue>();
+  pending_tasks_[TaskThread::QueryDb] = std::make_unique<TaskQueue>();
 }
 
 void TaskManager::Post(TaskThread thread, const TTask& task) {
diff --git a/src/threaded_queue.h b/src/threaded_queue.h
index 907e8da7..7b8ffe7e 100644
--- a/src/threaded_queue.h
+++ b/src/threaded_queue.h
@@ -1,7 +1,6 @@
 #pragma once
 
 #include "utils.h"
-#include "work_thread.h"
 
 #include <optional.h>
 
@@ -11,6 +10,7 @@
 #include <deque>
 #include <mutex>
 #include <tuple>
+#include <utility>
 
 // TODO: cleanup includes.
 
@@ -19,24 +19,6 @@ struct BaseThreadQueue {
   virtual ~BaseThreadQueue() = default;
 };
 
-// TODO Remove after migration to C++14
-namespace {
-
-template <size_t... Is>
-struct index_sequence {};
-
-template <size_t I, size_t... Is>
-struct make_index_sequence {
-  using type = typename make_index_sequence<I - 1, I - 1, Is...>::type;
-};
-
-template <size_t... Is>
-struct make_index_sequence<0, Is...> {
-  using type = index_sequence<Is...>;
-};
-
-}  // namespace
-
 // std::lock accepts two or more arguments. We define an overload for one
 // argument.
 namespace std {
@@ -51,20 +33,20 @@ struct MultiQueueLock {
   MultiQueueLock(Queue... lockable) : tuple_{lockable...} { lock(); }
   ~MultiQueueLock() { unlock(); }
   void lock() {
-    lock_impl(typename make_index_sequence<sizeof...(Queue)>::type{});
+    lock_impl(typename std::make_index_sequence<sizeof...(Queue)>{});
   }
   void unlock() {
-    unlock_impl(typename make_index_sequence<sizeof...(Queue)>::type{});
+    unlock_impl(typename std::make_index_sequence<sizeof...(Queue)>{});
   }
 
  private:
   template <size_t... Is>
-  void lock_impl(index_sequence<Is...>) {
+  void lock_impl(std::index_sequence<Is...>) {
     std::lock(std::get<Is>(tuple_)->mutex_...);
   }
 
   template <size_t... Is>
-  void unlock_impl(index_sequence<Is...>) {
+  void unlock_impl(std::index_sequence<Is...>) {
     (void)std::initializer_list<int>{
         (std::get<Is>(tuple_)->mutex_.unlock(), 0)...};
   }
@@ -96,9 +78,9 @@ template <class T>
 struct ThreadedQueue : public BaseThreadQueue {
  public:
   ThreadedQueue() : total_count_(0) {
-    owned_waiter_ = MakeUnique<MultiQueueWaiter>();
+    owned_waiter_ = std::make_unique<MultiQueueWaiter>();
     waiter_ = owned_waiter_.get();
-    owned_waiter1_ = MakeUnique<MultiQueueWaiter>();
+    owned_waiter1_ = std::make_unique<MultiQueueWaiter>();
     waiter1_ = owned_waiter1_.get();
   }
 
diff --git a/src/utils.h b/src/utils.h
index 204d3467..a602c760 100644
--- a/src/utils.h
+++ b/src/utils.h
@@ -111,14 +111,6 @@ struct TextReplacer {
 
 void WriteToFile(const std::string& filename, const std::string& content);
 
-// note: this implementation does not disable this overload for array types
-// See
-// http://en.cppreference.com/w/cpp/memory/unique_ptr/make_unique#Possible_Implementatiog
-template <typename T, typename... Args>
-std::unique_ptr<T> MakeUnique(Args&&... args) {
-  return std::unique_ptr<T>(new T(std::forward<Args>(args)...));
-}
-
 template <typename T>
 void AddRange(std::vector<T>* dest, const std::vector<T>& to_add) {
   dest->insert(dest->end(), to_add.begin(), to_add.end());
diff --git a/src/working_files.cc b/src/working_files.cc
index 2b2afea4..64c091c3 100644
--- a/src/working_files.cc
+++ b/src/working_files.cc
@@ -478,7 +478,7 @@ WorkingFile* WorkingFiles::OnOpen(const lsTextDocumentItem& open) {
     return file;
   }
 
-  files.push_back(MakeUnique<WorkingFile>(filename, content));
+  files.push_back(std::make_unique<WorkingFile>(filename, content));
   return files[files.size() - 1].get();
 }