polybar-dwm/include/utils/concurrency.hpp
2016-06-10 01:09:54 +02:00

125 lines
2.1 KiB
C++

#pragma once
#include <atomic>
#include <mutex>
#include <thread>
// Based on https://github.com/ademakov/Evenk
namespace concurrency
{
struct NoBackoff
{
bool operator()()
{
return true;
}
};
struct YieldBackoff
{
bool operator()()
{
std::this_thread::yield();
return false;
}
};
class SpinLock
{
std::atomic_flag lock_flag = ATOMIC_FLAG_INIT;
public:
SpinLock() = default;
SpinLock(const SpinLock &) = delete;
SpinLock &operator=(const SpinLock &) = delete;
void lock() noexcept
{
lock(NoBackoff {});
}
template <typename Backoff>
void lock(Backoff backoff) noexcept
{
while (lock_flag.test_and_set(std::memory_order_acquire)) {
backoff();
}
}
void unlock() noexcept
{
lock_flag.clear(std::memory_order_release);
}
};
template<typename T>
class Atomic
{
std::atomic<T> value;
public:
Atomic() = default;
explicit Atomic(T init) {
this->operator=(init);
}
void operator=(T value)
{
this->value = value;
}
T operator()()
{
return this->value;
}
operator bool()
{
return this->value;
}
bool operator==(T const& b)
{
return this->value == b;
}
};
template<typename T>
class Value
{
concurrency::SpinLock lock;
T value;
public:
Value() = default;
explicit Value(T init) {
this->operator=(init);
}
void operator=(T value)
{
std::lock_guard<concurrency::SpinLock> lck(this->lock);
this->value = value;
}
T operator()()
{
std::lock_guard<concurrency::SpinLock> lck(this->lock);
return this->value;
}
operator bool()
{
std::lock_guard<concurrency::SpinLock> lck(this->lock);
return this->value;
}
bool operator==(T const& b)
{
std::lock_guard<concurrency::SpinLock> lck(this->lock);
return this->value == b;
}
};
}