//
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// detail/completion_handler.hpp
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// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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//
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// Copyright (c) 2003-2020 Christopher M. Kohlhoff (chris at kohlhoff dot com)
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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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//
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#ifndef BOOST_ASIO_DETAIL_COMPLETION_HANDLER_HPP
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#define BOOST_ASIO_DETAIL_COMPLETION_HANDLER_HPP
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#if defined(_MSC_VER) && (_MSC_VER >= 1200)
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# pragma once
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#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
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#include <boost/asio/detail/config.hpp>
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#include <boost/asio/detail/fenced_block.hpp>
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#include <boost/asio/detail/handler_alloc_helpers.hpp>
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#include <boost/asio/detail/handler_work.hpp>
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#include <boost/asio/detail/memory.hpp>
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#include <boost/asio/detail/operation.hpp>
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#include <boost/asio/detail/push_options.hpp>
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namespace boost {
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namespace asio {
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namespace detail {
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template <typename Handler, typename IoExecutor>
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class completion_handler : public operation
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{
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public:
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BOOST_ASIO_DEFINE_HANDLER_PTR(completion_handler);
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completion_handler(Handler& h, const IoExecutor& io_ex)
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: operation(&completion_handler::do_complete),
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handler_(BOOST_ASIO_MOVE_CAST(Handler)(h)),
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work_(handler_, io_ex)
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{
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}
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static void do_complete(void* owner, operation* base,
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const boost::system::error_code& /*ec*/,
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std::size_t /*bytes_transferred*/)
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{
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// Take ownership of the handler object.
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completion_handler* h(static_cast<completion_handler*>(base));
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ptr p = { boost::asio::detail::addressof(h->handler_), h, h };
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BOOST_ASIO_HANDLER_COMPLETION((*h));
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// Take ownership of the operation's outstanding work.
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handler_work<Handler, IoExecutor> w(
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BOOST_ASIO_MOVE_CAST2(handler_work<Handler, IoExecutor>)(
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h->work_));
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// Make a copy of the handler so that the memory can be deallocated before
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// the upcall is made. Even if we're not about to make an upcall, a
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// sub-object of the handler may be the true owner of the memory associated
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// with the handler. Consequently, a local copy of the handler is required
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// to ensure that any owning sub-object remains valid until after we have
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// deallocated the memory here.
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Handler handler(BOOST_ASIO_MOVE_CAST(Handler)(h->handler_));
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p.h = boost::asio::detail::addressof(handler);
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p.reset();
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// Make the upcall if required.
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if (owner)
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{
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fenced_block b(fenced_block::half);
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BOOST_ASIO_HANDLER_INVOCATION_BEGIN(());
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w.complete(handler, handler);
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BOOST_ASIO_HANDLER_INVOCATION_END;
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}
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}
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private:
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Handler handler_;
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handler_work<Handler, IoExecutor> work_;
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};
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} // namespace detail
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} // namespace asio
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} // namespace boost
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#include <boost/asio/detail/pop_options.hpp>
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#endif // BOOST_ASIO_DETAIL_COMPLETION_HANDLER_HPP
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