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Diffstat (limited to '3rdparty/asio/include/asio/handler_invoke_hook.hpp')
-rw-r--r-- | 3rdparty/asio/include/asio/handler_invoke_hook.hpp | 111 |
1 files changed, 111 insertions, 0 deletions
diff --git a/3rdparty/asio/include/asio/handler_invoke_hook.hpp b/3rdparty/asio/include/asio/handler_invoke_hook.hpp new file mode 100644 index 00000000000..238745218b2 --- /dev/null +++ b/3rdparty/asio/include/asio/handler_invoke_hook.hpp @@ -0,0 +1,111 @@ +// +// handler_invoke_hook.hpp +// ~~~~~~~~~~~~~~~~~~~~~~~ +// +// Copyright (c) 2003-2021 Christopher M. Kohlhoff (chris at kohlhoff dot com) +// +// Distributed under the Boost Software License, Version 1.0. (See accompanying +// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) +// + +#ifndef ASIO_HANDLER_INVOKE_HOOK_HPP +#define ASIO_HANDLER_INVOKE_HOOK_HPP + +#if defined(_MSC_VER) && (_MSC_VER >= 1200) +# pragma once +#endif // defined(_MSC_VER) && (_MSC_VER >= 1200) + +#include "asio/detail/config.hpp" + +#include "asio/detail/push_options.hpp" + +namespace asio { + +/** @defgroup asio_handler_invoke asio::asio_handler_invoke + * + * @brief (Deprecated: Use the associated_executor trait.) Default invoke + * function for handlers. + * + * Completion handlers for asynchronous operations are invoked by the + * io_context associated with the corresponding object (e.g. a socket or + * deadline_timer). Certain guarantees are made on when the handler may be + * invoked, in particular that a handler can only be invoked from a thread that + * is currently calling @c run() on the corresponding io_context object. + * Handlers may subsequently be invoked through other objects (such as + * io_context::strand objects) that provide additional guarantees. + * + * When asynchronous operations are composed from other asynchronous + * operations, all intermediate handlers should be invoked using the same + * method as the final handler. This is required to ensure that user-defined + * objects are not accessed in a way that may violate the guarantees. This + * hooking function ensures that the invoked method used for the final handler + * is accessible at each intermediate step. + * + * Implement asio_handler_invoke for your own handlers to specify a custom + * invocation strategy. + * + * This default implementation invokes the function object like so: + * @code function(); @endcode + * If necessary, the default implementation makes a copy of the function object + * so that the non-const operator() can be used. + * + * @par Example + * @code + * class my_handler; + * + * template <typename Function> + * void asio_handler_invoke(Function function, my_handler* context) + * { + * context->strand_.dispatch(function); + * } + * @endcode + */ +/*@{*/ + +#if defined(ASIO_NO_DEPRECATED) + +// Places in asio that would have previously called the invocation hook to +// execute a handler, now call it only to check whether the result type is this +// type. If the result is not this type, it indicates that the user code still +// has the old hooks in place, and if so we want to trigger a compile error. +enum asio_handler_invoke_is_no_longer_used {}; + +typedef asio_handler_invoke_is_no_longer_used + asio_handler_invoke_is_deprecated; + +#else // defined(ASIO_NO_DEPRECATED) + +typedef void asio_handler_invoke_is_deprecated; + +#endif // defined(ASIO_NO_DEPRECATED) + +/// Default handler invocation hook used for non-const function objects. +template <typename Function> +inline asio_handler_invoke_is_deprecated +asio_handler_invoke(Function& function, ...) +{ + function(); +#if defined(ASIO_NO_DEPRECATED) + return asio_handler_invoke_is_no_longer_used(); +#endif // defined(ASIO_NO_DEPRECATED) +} + +/// Default handler invocation hook used for const function objects. +template <typename Function> +inline asio_handler_invoke_is_deprecated +asio_handler_invoke(const Function& function, ...) +{ + Function tmp(function); + tmp(); +#if defined(ASIO_NO_DEPRECATED) + return asio_handler_invoke_is_no_longer_used(); +#endif // defined(ASIO_NO_DEPRECATED) +} + +/*@}*/ + +} // namespace asio + +#include "asio/detail/pop_options.hpp" + +#endif // ASIO_HANDLER_INVOKE_HOOK_HPP |