97 lines
2.7 KiB
C++
97 lines
2.7 KiB
C++
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//
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// async_result.hpp
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// ~~~~~~~~~~~~~~~~
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//
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// Copyright (c) 2003-2016 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_ASYNC_RESULT_HPP
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#define BOOST_ASIO_ASYNC_RESULT_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/handler_type.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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/// An interface for customising the behaviour of an initiating function.
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/**
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* This template may be specialised for user-defined handler types.
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*/
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template <typename Handler>
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class async_result
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{
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public:
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/// The return type of the initiating function.
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typedef void type;
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/// Construct an async result from a given handler.
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/**
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* When using a specalised async_result, the constructor has an opportunity
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* to initialise some state associated with the handler, which is then
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* returned from the initiating function.
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*/
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explicit async_result(Handler&)
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{
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}
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/// Obtain the value to be returned from the initiating function.
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type get()
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{
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}
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};
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namespace detail {
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// Helper template to deduce the true type of a handler, capture a local copy
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// of the handler, and then create an async_result for the handler.
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template <typename Handler, typename Signature>
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struct async_result_init
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{
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explicit async_result_init(BOOST_ASIO_MOVE_ARG(Handler) orig_handler)
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: handler(BOOST_ASIO_MOVE_CAST(Handler)(orig_handler)),
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result(handler)
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{
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}
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typename handler_type<Handler, Signature>::type handler;
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async_result<typename handler_type<Handler, Signature>::type> result;
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};
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template <typename Handler, typename Signature>
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struct async_result_type_helper
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{
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typedef typename async_result<
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typename handler_type<Handler, Signature>::type
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>::type type;
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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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#if defined(GENERATING_DOCUMENTATION)
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# define BOOST_ASIO_INITFN_RESULT_TYPE(h, sig) \
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void_or_deduced
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#elif defined(_MSC_VER) && (_MSC_VER < 1500)
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# define BOOST_ASIO_INITFN_RESULT_TYPE(h, sig) \
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typename ::boost::asio::detail::async_result_type_helper<h, sig>::type
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#else
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# define BOOST_ASIO_INITFN_RESULT_TYPE(h, sig) \
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typename ::boost::asio::async_result< \
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typename ::boost::asio::handler_type<h, sig>::type>::type
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#endif
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#endif // BOOST_ASIO_ASYNC_RESULT_HPP
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