tdlight/tdutils/td/utils/port/detail/ThreadIdGuard.cpp

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//
// Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2020
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
#include "td/utils/port/detail/ThreadIdGuard.h"
#include "td/utils/common.h"
#include "td/utils/ExitGuard.h"
#include "td/utils/port/thread_local.h"
#include <mutex>
#include <set>
namespace td {
namespace detail {
class ThreadIdManager {
public:
int32 register_thread() {
std::lock_guard<std::mutex> guard(mutex_);
if (unused_thread_ids_.empty()) {
return ++max_thread_id_;
}
auto it = unused_thread_ids_.begin();
auto result = *it;
unused_thread_ids_.erase(it);
return result;
}
void unregister_thread(int32 thread_id) {
std::lock_guard<std::mutex> guard(mutex_);
CHECK(0 < thread_id && thread_id <= max_thread_id_);
bool is_inserted = unused_thread_ids_.insert(thread_id).second;
CHECK(is_inserted);
}
private:
std::mutex mutex_;
std::set<int32> unused_thread_ids_;
int32 max_thread_id_ = 0;
};
static ThreadIdManager thread_id_manager;
static ExitGuard exit_guard;
ThreadIdGuard::ThreadIdGuard() {
thread_id_ = thread_id_manager.register_thread();
set_thread_id(thread_id_);
}
ThreadIdGuard::~ThreadIdGuard() {
if (!ExitGuard::is_exited()) {
thread_id_manager.unregister_thread(thread_id_);
}
set_thread_id(0);
}
} // namespace detail
} // namespace td