concepts.h

Go to the documentation of this file.

// The MIT License (MIT)
//
// Copyright (c) 2021 Mateusz Pusz
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
 
#pragma once
 
#include <mp-coro/bits/get_awaiter.h>
#include <mp-coro/bits/type_traits.h>
#include <concepts>
#include <coroutine>
 
namespace mp_coro {
 
namespace detail {
 
template <typename Ret, typename Handle>
Handle func_arg(Ret (*)(Handle));
 
template <typename Ret, typename T, typename Handle>
Handle func_arg(Ret (T::*)(Handle));
 
template <typename Ret, typename T, typename Handle>
Handle func_arg(Ret (T::*)(Handle) &);
 
template <typename Ret, typename T, typename Handle>
Handle func_arg(Ret (T::*)(Handle) &&);
 
template <typename Ret, typename T, typename Handle>
Handle func_arg(Ret (T::*)(Handle) const);
 
template <typename Ret, typename T, typename Handle>
Handle func_arg(Ret (T::*)(Handle) const &);
 
template <typename Ret, typename T, typename Handle>
Handle func_arg(Ret (T::*)(Handle) const &&);
 
template <typename T>
concept suspend_return_type = std::is_void_v<T>       //
                           || std::is_same_v<T, bool> //
                           || specialization_of<T, std::coroutine_handle>;
 
} // namespace detail
 
template <typename T>
concept awaiter = requires(
    T &&t, decltype(detail::func_arg(&std::remove_reference_t<T>::await_suspend)) suspend_arg) {
    { std::forward<T>(t).await_ready() } -> std::convertible_to<bool>;
    { suspend_arg } -> std::convertible_to<std::coroutine_handle<>>;
    // TODO Why gcc does not inherit from `std::coroutine_handle<>`?
    { std::forward<T>(t).await_suspend(suspend_arg) } -> detail::suspend_return_type;
    std::forward<T>(t).await_resume();
};
 
template <typename T, typename Value>
concept awaiter_of = awaiter<T> &&requires(T &&t) {
    { std::forward<T>(t).await_resume() } -> std::same_as<Value>;
};
 
template <typename T>
concept awaitable = requires(T &&t) {
    { detail::get_awaiter(std::forward<T>(t)) } -> awaiter;
};
 
template <typename T, typename Value>
concept awaitable_of = awaitable<T> &&requires(T &&t) {
    { detail::get_awaiter(std::forward<T>(t)) } -> awaiter_of<Value>;
};
 
template <typename T>
concept task_value_type = std::move_constructible<T> || std::is_reference_v<T> || std::is_void_v<T>;
 
/// Type that supports the `notify_awaitable_completed()` member function used
/// by @ref mp_coro::detail::synchronized_task.
template <typename Sync>
concept sync_notification_type = requires(Sync s) {
    s.notify_awaitable_completed();
};
 
} // namespace mp_coro