forked from boostorg/beast
51f11f0902
The concept type traits are renamed for consistency, and consolidated into a single header file <beast/core/type_traits.hpp> A new section, Core Concepts, is added to the documentation describing all of the core utility classes and functions. This also includes a complete explanation and sample program describing how to write asynchronous initiation functions and their associated composed operations.
71 lines
2.1 KiB
C++
71 lines
2.1 KiB
C++
//
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// Copyright (c) 2013-2017 Vinnie Falco (vinnie dot falco at gmail 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 BEAST_BIND_HANDLER_HPP
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#define BEAST_BIND_HANDLER_HPP
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#include <beast/config.hpp>
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#include <beast/core/type_traits.hpp>
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#include <beast/core/detail/bind_handler.hpp>
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#include <type_traits>
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#include <utility>
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namespace beast {
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/** Bind parameters to a completion handler, creating a new handler.
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This function creates a new handler which, when invoked with no
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parameters, calls the original handler with the list of bound
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arguments. The passed handler and arguments are forwarded into
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the returned handler, which provides the same `io_service`
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execution guarantees as the original handler.
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Unlike `boost::asio::io_service::wrap`, the returned handler can
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be used in a subsequent call to `boost::asio::io_service::post`
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instead of `boost::asio::io_service::dispatch`, to ensure that
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the handler will not be invoked immediately by the calling
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function.
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Example:
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@code
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template<class AsyncReadStream, class ReadHandler>
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void
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signal_aborted(AsyncReadStream& stream, ReadHandler&& handler)
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{
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stream.get_io_service().post(
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bind_handler(std::forward<ReadHandler>(handler),
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boost::asio::error::operation_aborted, 0));
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}
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@endcode
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@param handler The handler to wrap.
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@param args A list of arguments to bind to the handler. The
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arguments are forwarded into the returned object.
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*/
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template<class Handler, class... Args>
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#if BEAST_DOXYGEN
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implementation_defined
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#else
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detail::bound_handler<
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typename std::decay<Handler>::type, Args...>
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#endif
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bind_handler(Handler&& handler, Args&&... args)
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{
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static_assert(is_completion_handler<
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Handler, void(Args...)>::value,
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"Handler requirements not met");
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return detail::bound_handler<typename std::decay<
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Handler>::type, Args...>(std::forward<
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Handler>(handler), std::forward<Args>(args)...);
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}
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} // beast
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#endif
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