576 lines
16 KiB
C++
576 lines
16 KiB
C++
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//
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// bind_executor.hpp
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// ~~~~~~~~~~~~~~~~~
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//
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// Copyright (c) 2003-2021 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_BIND_EXECUTOR_HPP
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#define ASIO_BIND_EXECUTOR_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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#include "asio/detail/type_traits.hpp"
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#include "asio/detail/variadic_templates.hpp"
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#include "asio/associated_executor.hpp"
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#include "asio/associated_allocator.hpp"
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#include "asio/async_result.hpp"
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#include "asio/execution/executor.hpp"
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#include "asio/execution_context.hpp"
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#include "asio/is_executor.hpp"
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#include "asio/uses_executor.hpp"
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#include "asio/detail/push_options.hpp"
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namespace asio {
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namespace detail {
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// Helper to automatically define nested typedef result_type.
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template <typename T, typename = void>
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struct executor_binder_result_type
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{
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protected:
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typedef void result_type_or_void;
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};
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template <typename T>
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struct executor_binder_result_type<T,
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typename void_type<typename T::result_type>::type>
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{
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typedef typename T::result_type result_type;
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protected:
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typedef result_type result_type_or_void;
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};
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template <typename R>
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struct executor_binder_result_type<R(*)()>
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{
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typedef R result_type;
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protected:
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typedef result_type result_type_or_void;
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};
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template <typename R>
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struct executor_binder_result_type<R(&)()>
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{
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typedef R result_type;
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protected:
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typedef result_type result_type_or_void;
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};
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template <typename R, typename A1>
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struct executor_binder_result_type<R(*)(A1)>
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{
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typedef R result_type;
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protected:
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typedef result_type result_type_or_void;
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};
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template <typename R, typename A1>
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struct executor_binder_result_type<R(&)(A1)>
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{
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typedef R result_type;
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protected:
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typedef result_type result_type_or_void;
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};
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template <typename R, typename A1, typename A2>
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struct executor_binder_result_type<R(*)(A1, A2)>
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{
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typedef R result_type;
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protected:
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typedef result_type result_type_or_void;
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};
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template <typename R, typename A1, typename A2>
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struct executor_binder_result_type<R(&)(A1, A2)>
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{
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typedef R result_type;
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protected:
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typedef result_type result_type_or_void;
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};
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// Helper to automatically define nested typedef argument_type.
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template <typename T, typename = void>
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struct executor_binder_argument_type {};
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template <typename T>
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struct executor_binder_argument_type<T,
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typename void_type<typename T::argument_type>::type>
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{
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typedef typename T::argument_type argument_type;
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};
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template <typename R, typename A1>
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struct executor_binder_argument_type<R(*)(A1)>
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{
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typedef A1 argument_type;
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};
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template <typename R, typename A1>
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struct executor_binder_argument_type<R(&)(A1)>
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{
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typedef A1 argument_type;
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};
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// Helper to automatically define nested typedefs first_argument_type and
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// second_argument_type.
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template <typename T, typename = void>
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struct executor_binder_argument_types {};
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template <typename T>
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struct executor_binder_argument_types<T,
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typename void_type<typename T::first_argument_type>::type>
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{
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typedef typename T::first_argument_type first_argument_type;
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typedef typename T::second_argument_type second_argument_type;
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};
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template <typename R, typename A1, typename A2>
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struct executor_binder_argument_type<R(*)(A1, A2)>
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{
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typedef A1 first_argument_type;
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typedef A2 second_argument_type;
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};
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template <typename R, typename A1, typename A2>
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struct executor_binder_argument_type<R(&)(A1, A2)>
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{
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typedef A1 first_argument_type;
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typedef A2 second_argument_type;
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};
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// Helper to perform uses_executor construction of the target type, if
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// required.
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template <typename T, typename Executor, bool UsesExecutor>
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class executor_binder_base;
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template <typename T, typename Executor>
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class executor_binder_base<T, Executor, true>
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{
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protected:
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template <typename E, typename U>
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executor_binder_base(ASIO_MOVE_ARG(E) e, ASIO_MOVE_ARG(U) u)
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: executor_(ASIO_MOVE_CAST(E)(e)),
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target_(executor_arg_t(), executor_, ASIO_MOVE_CAST(U)(u))
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{
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}
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Executor executor_;
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T target_;
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};
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template <typename T, typename Executor>
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class executor_binder_base<T, Executor, false>
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{
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protected:
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template <typename E, typename U>
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executor_binder_base(ASIO_MOVE_ARG(E) e, ASIO_MOVE_ARG(U) u)
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: executor_(ASIO_MOVE_CAST(E)(e)),
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target_(ASIO_MOVE_CAST(U)(u))
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{
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}
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Executor executor_;
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T target_;
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};
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// Helper to enable SFINAE on zero-argument operator() below.
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template <typename T, typename = void>
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struct executor_binder_result_of0
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{
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typedef void type;
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};
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template <typename T>
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struct executor_binder_result_of0<T,
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typename void_type<typename result_of<T()>::type>::type>
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{
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typedef typename result_of<T()>::type type;
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};
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} // namespace detail
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/// A call wrapper type to bind an executor of type @c Executor to an object of
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/// type @c T.
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template <typename T, typename Executor>
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class executor_binder
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#if !defined(GENERATING_DOCUMENTATION)
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: public detail::executor_binder_result_type<T>,
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public detail::executor_binder_argument_type<T>,
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public detail::executor_binder_argument_types<T>,
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private detail::executor_binder_base<
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T, Executor, uses_executor<T, Executor>::value>
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#endif // !defined(GENERATING_DOCUMENTATION)
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{
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public:
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/// The type of the target object.
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typedef T target_type;
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/// The type of the associated executor.
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typedef Executor executor_type;
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#if defined(GENERATING_DOCUMENTATION)
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/// The return type if a function.
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/**
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* The type of @c result_type is based on the type @c T of the wrapper's
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* target object:
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*
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* @li if @c T is a pointer to function type, @c result_type is a synonym for
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* the return type of @c T;
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*
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* @li if @c T is a class type with a member type @c result_type, then @c
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* result_type is a synonym for @c T::result_type;
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*
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* @li otherwise @c result_type is not defined.
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*/
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typedef see_below result_type;
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/// The type of the function's argument.
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/**
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* The type of @c argument_type is based on the type @c T of the wrapper's
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* target object:
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*
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* @li if @c T is a pointer to a function type accepting a single argument,
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* @c argument_type is a synonym for the return type of @c T;
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*
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* @li if @c T is a class type with a member type @c argument_type, then @c
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* argument_type is a synonym for @c T::argument_type;
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*
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* @li otherwise @c argument_type is not defined.
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*/
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typedef see_below argument_type;
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/// The type of the function's first argument.
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/**
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* The type of @c first_argument_type is based on the type @c T of the
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* wrapper's target object:
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*
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* @li if @c T is a pointer to a function type accepting two arguments, @c
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* first_argument_type is a synonym for the return type of @c T;
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*
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* @li if @c T is a class type with a member type @c first_argument_type,
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* then @c first_argument_type is a synonym for @c T::first_argument_type;
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*
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* @li otherwise @c first_argument_type is not defined.
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*/
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typedef see_below first_argument_type;
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/// The type of the function's second argument.
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/**
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* The type of @c second_argument_type is based on the type @c T of the
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* wrapper's target object:
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*
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* @li if @c T is a pointer to a function type accepting two arguments, @c
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* second_argument_type is a synonym for the return type of @c T;
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*
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* @li if @c T is a class type with a member type @c first_argument_type,
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* then @c second_argument_type is a synonym for @c T::second_argument_type;
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*
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* @li otherwise @c second_argument_type is not defined.
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*/
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typedef see_below second_argument_type;
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#endif // defined(GENERATING_DOCUMENTATION)
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/// Construct an executor wrapper for the specified object.
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/**
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* This constructor is only valid if the type @c T is constructible from type
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* @c U.
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*/
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template <typename U>
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executor_binder(executor_arg_t, const executor_type& e,
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ASIO_MOVE_ARG(U) u)
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: base_type(e, ASIO_MOVE_CAST(U)(u))
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{
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}
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/// Copy constructor.
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executor_binder(const executor_binder& other)
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: base_type(other.get_executor(), other.get())
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{
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}
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/// Construct a copy, but specify a different executor.
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executor_binder(executor_arg_t, const executor_type& e,
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const executor_binder& other)
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: base_type(e, other.get())
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{
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}
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/// Construct a copy of a different executor wrapper type.
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/**
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* This constructor is only valid if the @c Executor type is constructible
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* from type @c OtherExecutor, and the type @c T is constructible from type
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* @c U.
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*/
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template <typename U, typename OtherExecutor>
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executor_binder(const executor_binder<U, OtherExecutor>& other)
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: base_type(other.get_executor(), other.get())
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{
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}
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/// Construct a copy of a different executor wrapper type, but specify a
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/// different executor.
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/**
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* This constructor is only valid if the type @c T is constructible from type
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* @c U.
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*/
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template <typename U, typename OtherExecutor>
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executor_binder(executor_arg_t, const executor_type& e,
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const executor_binder<U, OtherExecutor>& other)
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: base_type(e, other.get())
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{
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}
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#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
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/// Move constructor.
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executor_binder(executor_binder&& other)
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: base_type(ASIO_MOVE_CAST(executor_type)(other.get_executor()),
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ASIO_MOVE_CAST(T)(other.get()))
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{
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}
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/// Move construct the target object, but specify a different executor.
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executor_binder(executor_arg_t, const executor_type& e,
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executor_binder&& other)
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: base_type(e, ASIO_MOVE_CAST(T)(other.get()))
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{
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}
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/// Move construct from a different executor wrapper type.
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template <typename U, typename OtherExecutor>
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executor_binder(executor_binder<U, OtherExecutor>&& other)
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: base_type(ASIO_MOVE_CAST(OtherExecutor)(other.get_executor()),
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ASIO_MOVE_CAST(U)(other.get()))
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{
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}
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/// Move construct from a different executor wrapper type, but specify a
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/// different executor.
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template <typename U, typename OtherExecutor>
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executor_binder(executor_arg_t, const executor_type& e,
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executor_binder<U, OtherExecutor>&& other)
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: base_type(e, ASIO_MOVE_CAST(U)(other.get()))
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{
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}
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#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
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/// Destructor.
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~executor_binder()
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{
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}
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/// Obtain a reference to the target object.
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target_type& get() ASIO_NOEXCEPT
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{
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return this->target_;
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}
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/// Obtain a reference to the target object.
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const target_type& get() const ASIO_NOEXCEPT
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{
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return this->target_;
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}
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/// Obtain the associated executor.
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executor_type get_executor() const ASIO_NOEXCEPT
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{
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return this->executor_;
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}
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#if defined(GENERATING_DOCUMENTATION)
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template <typename... Args> auto operator()(Args&& ...);
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template <typename... Args> auto operator()(Args&& ...) const;
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#elif defined(ASIO_HAS_VARIADIC_TEMPLATES)
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/// Forwarding function call operator.
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template <typename... Args>
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typename result_of<T(Args...)>::type operator()(
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ASIO_MOVE_ARG(Args)... args)
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{
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return this->target_(ASIO_MOVE_CAST(Args)(args)...);
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}
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/// Forwarding function call operator.
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template <typename... Args>
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typename result_of<T(Args...)>::type operator()(
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ASIO_MOVE_ARG(Args)... args) const
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{
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return this->target_(ASIO_MOVE_CAST(Args)(args)...);
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}
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#elif defined(ASIO_HAS_STD_TYPE_TRAITS) && !defined(_MSC_VER)
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typename detail::executor_binder_result_of0<T>::type operator()()
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{
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return this->target_();
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}
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typename detail::executor_binder_result_of0<T>::type operator()() const
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{
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return this->target_();
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}
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#define ASIO_PRIVATE_BIND_EXECUTOR_CALL_DEF(n) \
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template <ASIO_VARIADIC_TPARAMS(n)> \
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typename result_of<T(ASIO_VARIADIC_TARGS(n))>::type operator()( \
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ASIO_VARIADIC_MOVE_PARAMS(n)) \
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{ \
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return this->target_(ASIO_VARIADIC_MOVE_ARGS(n)); \
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} \
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\
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template <ASIO_VARIADIC_TPARAMS(n)> \
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typename result_of<T(ASIO_VARIADIC_TARGS(n))>::type operator()( \
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ASIO_VARIADIC_MOVE_PARAMS(n)) const \
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||
|
{ \
|
||
|
return this->target_(ASIO_VARIADIC_MOVE_ARGS(n)); \
|
||
|
} \
|
||
|
/**/
|
||
|
ASIO_VARIADIC_GENERATE(ASIO_PRIVATE_BIND_EXECUTOR_CALL_DEF)
|
||
|
#undef ASIO_PRIVATE_BIND_EXECUTOR_CALL_DEF
|
||
|
|
||
|
#else // defined(ASIO_HAS_STD_TYPE_TRAITS) && !defined(_MSC_VER)
|
||
|
|
||
|
typedef typename detail::executor_binder_result_type<T>::result_type_or_void
|
||
|
result_type_or_void;
|
||
|
|
||
|
result_type_or_void operator()()
|
||
|
{
|
||
|
return this->target_();
|
||
|
}
|
||
|
|
||
|
result_type_or_void operator()() const
|
||
|
{
|
||
|
return this->target_();
|
||
|
}
|
||
|
|
||
|
#define ASIO_PRIVATE_BIND_EXECUTOR_CALL_DEF(n) \
|
||
|
template <ASIO_VARIADIC_TPARAMS(n)> \
|
||
|
result_type_or_void operator()( \
|
||
|
ASIO_VARIADIC_MOVE_PARAMS(n)) \
|
||
|
{ \
|
||
|
return this->target_(ASIO_VARIADIC_MOVE_ARGS(n)); \
|
||
|
} \
|
||
|
\
|
||
|
template <ASIO_VARIADIC_TPARAMS(n)> \
|
||
|
result_type_or_void operator()( \
|
||
|
ASIO_VARIADIC_MOVE_PARAMS(n)) const \
|
||
|
{ \
|
||
|
return this->target_(ASIO_VARIADIC_MOVE_ARGS(n)); \
|
||
|
} \
|
||
|
/**/
|
||
|
ASIO_VARIADIC_GENERATE(ASIO_PRIVATE_BIND_EXECUTOR_CALL_DEF)
|
||
|
#undef ASIO_PRIVATE_BIND_EXECUTOR_CALL_DEF
|
||
|
|
||
|
#endif // defined(ASIO_HAS_STD_TYPE_TRAITS) && !defined(_MSC_VER)
|
||
|
|
||
|
private:
|
||
|
typedef detail::executor_binder_base<T, Executor,
|
||
|
uses_executor<T, Executor>::value> base_type;
|
||
|
};
|
||
|
|
||
|
/// Associate an object of type @c T with an executor of type @c Executor.
|
||
|
template <typename Executor, typename T>
|
||
|
inline executor_binder<typename decay<T>::type, Executor>
|
||
|
bind_executor(const Executor& ex, ASIO_MOVE_ARG(T) t,
|
||
|
typename constraint<
|
||
|
is_executor<Executor>::value || execution::is_executor<Executor>::value
|
||
|
>::type = 0)
|
||
|
{
|
||
|
return executor_binder<typename decay<T>::type, Executor>(
|
||
|
executor_arg_t(), ex, ASIO_MOVE_CAST(T)(t));
|
||
|
}
|
||
|
|
||
|
/// Associate an object of type @c T with an execution context's executor.
|
||
|
template <typename ExecutionContext, typename T>
|
||
|
inline executor_binder<typename decay<T>::type,
|
||
|
typename ExecutionContext::executor_type>
|
||
|
bind_executor(ExecutionContext& ctx, ASIO_MOVE_ARG(T) t,
|
||
|
typename constraint<is_convertible<
|
||
|
ExecutionContext&, execution_context&>::value>::type = 0)
|
||
|
{
|
||
|
return executor_binder<typename decay<T>::type,
|
||
|
typename ExecutionContext::executor_type>(
|
||
|
executor_arg_t(), ctx.get_executor(), ASIO_MOVE_CAST(T)(t));
|
||
|
}
|
||
|
|
||
|
#if !defined(GENERATING_DOCUMENTATION)
|
||
|
|
||
|
template <typename T, typename Executor>
|
||
|
struct uses_executor<executor_binder<T, Executor>, Executor>
|
||
|
: true_type {};
|
||
|
|
||
|
template <typename T, typename Executor, typename Signature>
|
||
|
class async_result<executor_binder<T, Executor>, Signature>
|
||
|
{
|
||
|
public:
|
||
|
typedef executor_binder<
|
||
|
typename async_result<T, Signature>::completion_handler_type, Executor>
|
||
|
completion_handler_type;
|
||
|
|
||
|
typedef typename async_result<T, Signature>::return_type return_type;
|
||
|
|
||
|
explicit async_result(executor_binder<T, Executor>& b)
|
||
|
: target_(b.get())
|
||
|
{
|
||
|
}
|
||
|
|
||
|
return_type get()
|
||
|
{
|
||
|
return target_.get();
|
||
|
}
|
||
|
|
||
|
private:
|
||
|
async_result(const async_result&) ASIO_DELETED;
|
||
|
async_result& operator=(const async_result&) ASIO_DELETED;
|
||
|
|
||
|
async_result<T, Signature> target_;
|
||
|
};
|
||
|
|
||
|
template <typename T, typename Executor, typename Allocator>
|
||
|
struct associated_allocator<executor_binder<T, Executor>, Allocator>
|
||
|
{
|
||
|
typedef typename associated_allocator<T, Allocator>::type type;
|
||
|
|
||
|
static type get(const executor_binder<T, Executor>& b,
|
||
|
const Allocator& a = Allocator()) ASIO_NOEXCEPT
|
||
|
{
|
||
|
return associated_allocator<T, Allocator>::get(b.get(), a);
|
||
|
}
|
||
|
};
|
||
|
|
||
|
template <typename T, typename Executor, typename Executor1>
|
||
|
struct associated_executor<executor_binder<T, Executor>, Executor1>
|
||
|
{
|
||
|
typedef Executor type;
|
||
|
|
||
|
static type get(const executor_binder<T, Executor>& b,
|
||
|
const Executor1& = Executor1()) ASIO_NOEXCEPT
|
||
|
{
|
||
|
return b.get_executor();
|
||
|
}
|
||
|
};
|
||
|
|
||
|
#endif // !defined(GENERATING_DOCUMENTATION)
|
||
|
|
||
|
} // namespace asio
|
||
|
|
||
|
#include "asio/detail/pop_options.hpp"
|
||
|
|
||
|
#endif // ASIO_BIND_EXECUTOR_HPP
|