61 lines
1.1 KiB
C++
61 lines
1.1 KiB
C++
//
|
|
// Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2023
|
|
//
|
|
// 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)
|
|
//
|
|
#pragma once
|
|
|
|
#include "td/utils/port/sleep.h"
|
|
|
|
#include <atomic>
|
|
#include <memory>
|
|
|
|
namespace td {
|
|
|
|
class SpinLock {
|
|
struct Unlock {
|
|
void operator()(SpinLock *ptr) {
|
|
ptr->unlock();
|
|
}
|
|
};
|
|
|
|
class InfBackoff {
|
|
int cnt = 0;
|
|
|
|
public:
|
|
bool next() {
|
|
cnt++;
|
|
if (cnt < 50) {
|
|
//TODO pause
|
|
return true;
|
|
} else {
|
|
usleep_for(1);
|
|
return true;
|
|
}
|
|
}
|
|
};
|
|
|
|
public:
|
|
using Lock = std::unique_ptr<SpinLock, Unlock>;
|
|
|
|
Lock lock() {
|
|
InfBackoff backoff;
|
|
while (!try_lock()) {
|
|
backoff.next();
|
|
}
|
|
return Lock(this);
|
|
}
|
|
bool try_lock() {
|
|
return !flag_.test_and_set(std::memory_order_acquire);
|
|
}
|
|
|
|
private:
|
|
std::atomic_flag flag_ = ATOMIC_FLAG_INIT;
|
|
void unlock() {
|
|
flag_.clear(std::memory_order_release);
|
|
}
|
|
};
|
|
|
|
} // namespace td
|