127 lines
3.1 KiB
C++
127 lines
3.1 KiB
C++
//
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// packaged_task.hpp
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// ~~~~~~~~~~~~~~~~~
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//
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// Copyright (c) 2003-2018 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 ASIO_PACKAGED_TASK_HPP
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#define ASIO_PACKAGED_TASK_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 "asio/detail/config.hpp"
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#if defined(ASIO_HAS_STD_FUTURE) \
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|| defined(GENERATING_DOCUMENTATION)
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#include <future>
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#include "asio/async_result.hpp"
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#include "asio/detail/type_traits.hpp"
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#include "asio/detail/variadic_templates.hpp"
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#include "asio/detail/push_options.hpp"
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namespace asio {
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#if defined(ASIO_HAS_VARIADIC_TEMPLATES) \
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|| defined(GENERATING_DOCUMENTATION)
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/// Partial specialisation of @c async_result for @c std::packaged_task.
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template <typename Result, typename... Args, typename Signature>
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class async_result<std::packaged_task<Result(Args...)>, Signature>
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{
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public:
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/// The packaged task is the concrete completion handler type.
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typedef std::packaged_task<Result(Args...)> completion_handler_type;
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/// The return type of the initiating function is the future obtained from
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/// the packaged task.
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typedef std::future<Result> return_type;
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/// The constructor extracts the future from the packaged task.
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explicit async_result(completion_handler_type& h)
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: future_(h.get_future())
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{
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}
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/// Returns the packaged task's future.
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return_type get()
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{
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return std::move(future_);
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}
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private:
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return_type future_;
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};
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#else // defined(ASIO_HAS_VARIADIC_TEMPLATES)
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// || defined(GENERATING_DOCUMENTATION)
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template <typename Result, typename Signature>
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struct async_result<std::packaged_task<Result()>, Signature>
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{
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typedef std::packaged_task<Result()> completion_handler_type;
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typedef std::future<Result> return_type;
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explicit async_result(completion_handler_type& h)
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: future_(h.get_future())
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{
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}
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return_type get()
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{
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return std::move(future_);
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}
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private:
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return_type future_;
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};
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#define ASIO_PRIVATE_ASYNC_RESULT_DEF(n) \
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template <typename Result, \
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ASIO_VARIADIC_TPARAMS(n), typename Signature> \
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class async_result< \
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std::packaged_task<Result(ASIO_VARIADIC_TARGS(n))>, Signature> \
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{ \
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public: \
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typedef std::packaged_task< \
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Result(ASIO_VARIADIC_TARGS(n))> \
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completion_handler_type; \
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\
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typedef std::future<Result> return_type; \
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\
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explicit async_result(completion_handler_type& h) \
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: future_(h.get_future()) \
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{ \
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} \
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\
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return_type get() \
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{ \
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return std::move(future_); \
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} \
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\
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private: \
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return_type future_; \
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}; \
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/**/
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ASIO_VARIADIC_GENERATE(ASIO_PRIVATE_ASYNC_RESULT_DEF)
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#undef ASIO_PRIVATE_ASYNC_RESULT_DEF
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#endif // defined(ASIO_HAS_VARIADIC_TEMPLATES)
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// || defined(GENERATING_DOCUMENTATION)
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} // namespace asio
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#include "asio/detail/pop_options.hpp"
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#endif // defined(ASIO_HAS_STD_FUTURE)
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// || defined(GENERATING_DOCUMENTATION)
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#endif // ASIO_PACKAGED_TASK_HPP
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