149 lines
3.9 KiB
C++
149 lines
3.9 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/receiver_concepts.hpp>
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#include <unifex/sender_concepts.hpp>
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#include <unifex/stream_concepts.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/scope_guard.hpp>
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#include <unifex/bind_back.hpp>
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#include <optional>
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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 _single {
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template <typename Sender, typename Receiver>
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struct _next_op {
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struct type;
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};
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template <typename Sender, typename Receiver>
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using next_operation = typename _next_op<Sender, remove_cvref_t<Receiver>>::type;
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template <typename Sender, typename Receiver>
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struct _next_op<Sender, Receiver>::type {
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union {
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Receiver receiver_;
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manual_lifetime<connect_result_t<Sender, Receiver>> innerOp_;
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};
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bool done_;
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template(typename Receiver2)
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(requires constructible_from<Receiver, Receiver2>)
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explicit type(Receiver2&& receiver)
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: receiver_((Receiver2&&)receiver)
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, done_(true)
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{}
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explicit type(Sender&& sender, Receiver&& receiver)
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: done_(false)
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{
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unifex::activate_union_member_with(innerOp_, [&] {
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return unifex::connect(
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static_cast<Sender&&>(sender), (Receiver&&)receiver);
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});
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}
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~type() {
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if (done_) {
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receiver_.~Receiver();
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} else {
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unifex::deactivate_union_member(innerOp_);
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}
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}
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void start() noexcept {
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if (done_) {
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unifex::set_done(std::move(receiver_));
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} else {
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unifex::start(innerOp_.get());
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}
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}
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};
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template <typename Sender>
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struct _stream {
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struct type;
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};
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template <typename Sender>
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using stream = typename _stream<remove_cvref_t<Sender>>::type;
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template <typename Sender>
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struct _stream<Sender>::type {
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std::optional<Sender> sender_;
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struct next_sender {
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std::optional<Sender> sender_;
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template <template <typename...> class Variant,
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template <typename...> class Tuple>
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using value_types = sender_value_types_t<Sender, Variant, Tuple>;
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template <template <typename...> class Variant>
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using error_types = sender_error_types_t<Sender, Variant>;
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static constexpr bool sends_done = true;
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template <typename Receiver>
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auto connect(Receiver&& receiver) {
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if (sender_) {
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return next_operation<Sender, Receiver>{*std::move(sender_), (Receiver&&)receiver};
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} else {
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return next_operation<Sender, Receiver>{(Receiver&&)receiver};
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}
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}
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};
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friend next_sender tag_invoke(tag_t<next>, type& s) {
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scope_guard g{[&]() noexcept { s.sender_.reset(); }};
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return next_sender{std::move(s.sender_)};
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}
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friend ready_done_sender tag_invoke(tag_t<cleanup>, type&) noexcept {
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return {};
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}
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template <typename Sender2>
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explicit type(Sender2&& sender)
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: sender_(std::in_place, (Sender2&&)sender) {}
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};
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} // namespace _single
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namespace _single_cpo {
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inline const struct _fn {
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template <typename Sender>
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auto operator()(Sender&& sender) const {
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return _single::stream<Sender>{(Sender&&)sender};
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}
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constexpr auto operator()() const
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noexcept(is_nothrow_callable_v<
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tag_t<bind_back>, _fn>)
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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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} single{};
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} // namespace _single_cpo
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using _single_cpo::single;
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} // namespace unifex
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#include <unifex/detail/epilogue.hpp>
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