108 lines
2.9 KiB
C++
108 lines
2.9 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 <unifex/config.hpp>
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#include <unifex/get_stop_token.hpp>
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#include <unifex/manual_lifetime.hpp>
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#include <unifex/ready_done_sender.hpp>
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#include <unifex/receiver_concepts.hpp>
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#include <unifex/stop_token_concepts.hpp>
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#include <unifex/get_stop_token.hpp>
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#include <unifex/stream_concepts.hpp>
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#include <type_traits>
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#include <unifex/detail/prologue.hpp>
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namespace unifex {
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namespace _never {
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template <typename Receiver>
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struct _op {
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struct type;
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};
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template <typename Receiver>
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using operation = typename _op<remove_cvref_t<Receiver>>::type;
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template <typename Receiver>
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struct _op<Receiver>::type {
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struct cancel_callback {
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type& op_;
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void operator()() noexcept {
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op_.stopCallback_.destruct();
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unifex::set_done(static_cast<Receiver&&>(op_.receiver_));
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}
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};
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using stop_token_type = stop_token_type_t<Receiver&>;
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static_assert(
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!is_stop_never_possible_v<stop_token_type>,
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"never should not be used with a stop-token "
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"type that can never be stopped.");
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UNIFEX_NO_UNIQUE_ADDRESS Receiver receiver_;
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manual_lifetime<
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typename stop_token_type::
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template callback_type<cancel_callback>>
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stopCallback_;
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template(typename Receiver2)
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(requires constructible_from<Receiver, Receiver2>)
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type(Receiver2&& receiver)
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: receiver_((Receiver2 &&) receiver) {}
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void start() noexcept {
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UNIFEX_ASSERT(get_stop_token(receiver_).stop_possible());
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stopCallback_.construct(
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get_stop_token(receiver_), cancel_callback{*this});
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}
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};
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struct sender {
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template <
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template <typename...> class Variant,
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template <typename...> class Tuple>
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using value_types = Variant<>;
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template <template <typename...> class Variant>
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using error_types = Variant<>;
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static constexpr bool sends_done = true;
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template <typename Receiver>
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operation<Receiver> connect(Receiver&& receiver) {
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return operation<Receiver>{(Receiver &&) receiver};
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}
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};
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struct stream {
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friend constexpr sender tag_invoke(tag_t<next>, stream&) noexcept {
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return {};
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}
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friend constexpr ready_done_sender tag_invoke(tag_t<cleanup>, stream&) noexcept {
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return {};
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}
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};
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} // namespace _never
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using never_sender = _never::sender;
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using never_stream = _never::stream;
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} // namespace unifex
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#include <unifex/detail/epilogue.hpp>
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