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tdlib-fork/tdutils/td/utils/port/detail/ThreadIdGuard.cpp

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//
// Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2018
//
// 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/logging.h"
#include "td/utils/port/thread_local.h"
#include <array>
#include <mutex>
namespace td {
namespace detail {
class ThreadIdManager {
public:
int32 register_thread() {
std::lock_guard<std::mutex> guard(mutex_);
for (size_t i = 0; i < is_id_used_.size(); i++) {
if (!is_id_used_[i]) {
is_id_used_[i] = true;
return static_cast<int32>(i + 1);
}
}
LOG(FATAL) << "Cannot create more than " << max_thread_count() << " threads";
return 0;
}
void unregister_thread(int32 thread_id) {
thread_id--;
std::lock_guard<std::mutex> guard(mutex_);
CHECK(is_id_used_.at(thread_id));
is_id_used_[thread_id] = false;
}
private:
std::mutex mutex_;
std::array<bool, max_thread_count()> is_id_used_{{false}};
};
static ThreadIdManager thread_id_manager;
ThreadIdGuard::ThreadIdGuard() {
thread_id_ = thread_id_manager.register_thread();
set_thread_id(thread_id_);
}
ThreadIdGuard::~ThreadIdGuard() {
thread_id_manager.unregister_thread(thread_id_);
set_thread_id(0);
}
} // namespace detail
} // namespace td