nonvoid_storage.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/storage.h>
#include <mp-coro/type_traits.h>
 
namespace mp_coro {
 
struct void_type {};
 
template <typename T>
using nonvoid_await_result_t =
    std::conditional_t<std::is_void_v<await_result_t<T>>, void_type, await_result_t<T>>;
 
namespace detail {
 
template <typename T>
class nonvoid_storage : public storage<T> {
  public:
    using value_type = typename storage<T>::value_type;
 
    [[nodiscard]] const value_type &nonvoid_get() const & { return this->get(); }
    [[nodiscard]] value_type &&nonvoid_get() && { return std::move(*this).get(); }
 
    [[nodiscard]] T &nonvoid_get() const &requires std::is_reference_v<T> { return this->get(); }
};
 
template <>
class nonvoid_storage<void> : public storage<void> {
  public:
    using value_type = void_type;
 
    [[nodiscard]] void_type nonvoid_get() const {
        check_and_rethrow(this->result);
        return void_type {};
    }
};
 
} // namespace detail
} // namespace mp_coro