61 lines
1.8 KiB
C++
61 lines
1.8 KiB
C++
/*
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* Copyright (c) Facebook, Inc. and its affiliates.
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*
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* Licensed under the Apache License Version 2.0 with LLVM Exceptions
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* (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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*
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* https://llvm.org/LICENSE.txt
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#pragma once
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#include <optional>
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#include <unifex/config.hpp>
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#include <unifex/then.hpp>
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#include <unifex/let_done.hpp>
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#include <unifex/just.hpp>
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#include <unifex/type_traits.hpp>
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#include <unifex/bind_back.hpp>
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#include <unifex/sender_concepts.hpp>
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#include <unifex/detail/prologue.hpp>
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namespace unifex {
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namespace _done_as_opt {
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namespace _cpo {
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inline const struct _fn {
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template(typename Sender) //
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(requires _single_typed_sender<Sender>) //
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auto operator()(Sender&& predecessor) const {
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using optional_t = std::optional<
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non_void_t<std::decay_t<sender_single_value_return_type_t<Sender>>>>;
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return let_done(
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then(
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(Sender&&) predecessor,
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[](auto&&... ts) noexcept(
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noexcept(optional_t{std::in_place, (decltype(ts)) ts...})) {
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return optional_t{std::in_place, (decltype(ts)) ts...};
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}),
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[]() noexcept { return just(optional_t{}); });
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}
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constexpr auto operator()() const noexcept
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-> bind_back_result_t<_fn> {
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return bind_back(*this);
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}
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} done_as_optional{};
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} // namespace _cpo
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} // namespace _done_as_opt
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using _done_as_opt::_cpo::done_as_optional;
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} // namespace unifex
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#include <unifex/detail/epilogue.hpp>
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