atomic_wait.hpp

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#pragma once
 
#include <yaclib/config.hpp>
#include <yaclib/fault/detail/fiber/queue.hpp>
#include <yaclib/fault/inject.hpp>
 
namespace yaclib::detail::fiber {
 
template <typename T>
class AtomicWait {
 public:
  AtomicWait() noexcept = default;
 
  constexpr AtomicWait(T desired) noexcept : _value(desired) {
  }
 
  T operator=(T desired) volatile noexcept {
    return _value = desired;
  }
 
  T operator=(T desired) noexcept {
    return _value = desired;
  }
 
  [[nodiscard]] bool is_lock_free() const volatile noexcept {
    return true;
  }
 
  [[nodiscard]] bool is_lock_free() const noexcept {
    return true;
  }
 
  static constexpr bool is_always_lock_free = true;
 
#if YACLIB_FUTEX != 0
  void wait(T old, std::memory_order) const noexcept {
    while (_value == old) {
      const_cast<FiberQueue*>(&_queue)->Wait(NoTimeoutTag{});
    }
  }
  void wait(T old, std::memory_order) const volatile noexcept {
    while (_value == old) {
      const_cast<FiberQueue*>(&_queue)->Wait(NoTimeoutTag{});
    }
  }
 
  void notify_one() noexcept {
    _queue.NotifyOne();
  }
  void notify_one() volatile noexcept {
    const_cast<FiberQueue*>(&_queue)->NotifyOne();
  }
 
  void notify_all() noexcept {
    _queue.NotifyAll();
  }
  void notify_all() volatile noexcept {
    const_cast<FiberQueue*>(&_queue)->NotifyAll();
  }
#endif
 
 protected:
  T _value;
#if YACLIB_FUTEX != 0
  FiberQueue _queue;
#endif
};
 
}  // namespace yaclib::detail::fiber