105 lines
2.9 KiB
C++
105 lines
2.9 KiB
C++
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// Copyright (c) 2022 Klemens D. Morgenstern
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//
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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#ifndef BOOST_COBALT_WAIT_GROUP_HPP
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#define BOOST_COBALT_WAIT_GROUP_HPP
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#include <boost/cobalt/detail/wait_group.hpp>
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namespace boost::cobalt
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{
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// tag::outline[]
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struct wait_group
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{
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// create a wait_group
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explicit
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wait_group(asio::cancellation_type normal_cancel = asio::cancellation_type::none,
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asio::cancellation_type exception_cancel = asio::cancellation_type::all);
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// insert a task into the group
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void push_back(promise<void> p);
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// the number of tasks in the group
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std::size_t size() const;
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// remove completed tasks without waiting (i.e. zombie tasks)
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std::size_t reap();
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// cancel all tasks
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void cancel(asio::cancellation_type ct = asio::cancellation_type::all);
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// end::outline[]
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/* tag::outline[]
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// wait for one task to complete.
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__wait_one_op__ wait_one();
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// wait for all tasks to complete
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__wait_op__ wait();
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// wait for all tasks to complete
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__wait_op__ operator co_await ();
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// when used with `with` , this will receive the exception
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// and wait for the completion
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// if `ep` is set, this will use the `exception_cancel` level,
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// otherwise the `normal_cancel` to cancel all promises.
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__wait_op__ await_exit(std::exception_ptr ep);
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end::outline[] */
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auto wait_one() -> detail::race_wrapper
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{
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return detail::race_wrapper(waitables_);
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}
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detail::gather_wrapper wait()
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{
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return detail::gather_wrapper(waitables_);
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}
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detail::gather_wrapper::awaitable_type operator co_await ()
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{
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return detail::gather_wrapper(waitables_).operator co_await();
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}
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// swallow the exception here.
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detail::gather_wrapper await_exit(std::exception_ptr ep)
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{
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auto ct = ep ? ct_except_ : ct_normal_;
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if (ct != asio::cancellation_type::none)
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for (auto & w : waitables_)
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w.cancel(ct);
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return detail::gather_wrapper(waitables_);
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}
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private:
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std::list<promise<void>> waitables_;
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asio::cancellation_type ct_normal_, ct_except_;
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// tag::outline[]
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};
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// end::outline[]
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inline wait_group::wait_group(
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asio::cancellation_type normal_cancel,
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asio::cancellation_type exception_cancel)
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: ct_normal_(normal_cancel), ct_except_(exception_cancel) {}
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inline
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std::size_t wait_group::size() const {return waitables_.size();}
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inline
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std::size_t wait_group::reap()
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{
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return erase_if(waitables_, [](promise<void> & p) { return p.ready() && p;});
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}
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inline
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void wait_group::cancel(asio::cancellation_type ct)
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{
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for (auto & w : waitables_)
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w.cancel(ct);
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}
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inline
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void wait_group::push_back(promise<void> p) { waitables_.push_back(std::move(p));}
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}
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#endif //BOOST_COBALT_WAIT_GROUP_HPP
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