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- //
- // bind_executor.hpp
- // ~~~~~~~~~~~~~~~~~
- //
- // Copyright (c) 2003-2015 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_BIND_EXECUTOR_HPP
- #define ASIO_BIND_EXECUTOR_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/type_traits.hpp"
- #include "asio/detail/variadic_templates.hpp"
- #include "asio/associated_allocator.hpp"
- #include "asio/async_result.hpp"
- #include "asio/handler_type.hpp"
- #include "asio/uses_executor.hpp"
-
- #include "asio/detail/push_options.hpp"
-
- namespace asio {
- namespace detail {
-
- template <typename T>
- struct executor_binder_check
- {
- typedef void type;
- };
-
- // Helper to automatically define nested typedef result_type.
-
- template <typename T, typename = void>
- struct executor_binder_result_type
- {
- protected:
- typedef void result_type_or_void;
- };
-
- template <typename T>
- struct executor_binder_result_type<T,
- typename executor_binder_check<typename T::result_type>::type>
- {
- typedef typename T::result_type result_type;
- protected:
- typedef result_type result_type_or_void;
- };
-
- template <typename R>
- struct executor_binder_result_type<R(*)()>
- {
- typedef R result_type;
- protected:
- typedef result_type result_type_or_void;
- };
-
- template <typename R>
- struct executor_binder_result_type<R(&)()>
- {
- typedef R result_type;
- protected:
- typedef result_type result_type_or_void;
- };
-
- template <typename R, typename A1>
- struct executor_binder_result_type<R(*)(A1)>
- {
- typedef R result_type;
- protected:
- typedef result_type result_type_or_void;
- };
-
- template <typename R, typename A1>
- struct executor_binder_result_type<R(&)(A1)>
- {
- typedef R result_type;
- protected:
- typedef result_type result_type_or_void;
- };
-
- template <typename R, typename A1, typename A2>
- struct executor_binder_result_type<R(*)(A1, A2)>
- {
- typedef R result_type;
- protected:
- typedef result_type result_type_or_void;
- };
-
- template <typename R, typename A1, typename A2>
- struct executor_binder_result_type<R(&)(A1, A2)>
- {
- typedef R result_type;
- protected:
- typedef result_type result_type_or_void;
- };
-
- // Helper to automatically define nested typedef argument_type.
-
- template <typename T, typename = void>
- struct executor_binder_argument_type {};
-
- template <typename T>
- struct executor_binder_argument_type<T,
- typename executor_binder_check<typename T::argument_type>::type>
- {
- typedef typename T::argument_type argument_type;
- };
-
- template <typename R, typename A1>
- struct executor_binder_argument_type<R(*)(A1)>
- {
- typedef A1 argument_type;
- };
-
- template <typename R, typename A1>
- struct executor_binder_argument_type<R(&)(A1)>
- {
- typedef A1 argument_type;
- };
-
- // Helper to automatically define nested typedefs first_argument_type and
- // second_argument_type.
-
- template <typename T, typename = void>
- struct executor_binder_argument_types {};
-
- template <typename T>
- struct executor_binder_argument_types<T,
- typename executor_binder_check<typename T::first_argument_type>::type>
- {
- typedef typename T::first_argument_type first_argument_type;
- typedef typename T::second_argument_type second_argument_type;
- };
-
- template <typename R, typename A1, typename A2>
- struct executor_binder_argument_type<R(*)(A1, A2)>
- {
- typedef A1 first_argument_type;
- typedef A2 second_argument_type;
- };
-
- template <typename R, typename A1, typename A2>
- struct executor_binder_argument_type<R(&)(A1, A2)>
- {
- typedef A1 first_argument_type;
- typedef A2 second_argument_type;
- };
-
- // Helper to:
- // - Apply the empty base optimisation to the executor.
- // - Perform uses_executor construction of the target type, if required.
-
- template <typename T, typename Executor, bool UsesExecutor>
- class executor_binder_base;
-
- template <typename T, typename Executor>
- class executor_binder_base<T, Executor, true>
- : protected Executor
- {
- protected:
- template <typename E, typename U>
- executor_binder_base(ASIO_MOVE_ARG(E) e, ASIO_MOVE_ARG(U) u)
- : Executor(ASIO_MOVE_CAST(E)(e)),
- target_(executor_arg_t(), static_cast<const Executor&>(*this),
- ASIO_MOVE_CAST(U)(u))
- {
- }
-
- T target_;
- };
-
- template <typename T, typename Executor>
- class executor_binder_base<T, Executor, false>
- : protected Executor
- {
- protected:
- template <typename E, typename U>
- executor_binder_base(ASIO_MOVE_ARG(E) e, ASIO_MOVE_ARG(U) u)
- : Executor(ASIO_MOVE_CAST(E)(e)),
- target_(ASIO_MOVE_CAST(U)(u))
- {
- }
-
- T target_;
- };
-
- // Helper to enable SFINAE on zero-argument operator() below.
-
- template <typename T, typename = void>
- struct executor_binder_result_of0
- {
- typedef void type;
- };
-
- template <typename T>
- struct executor_binder_result_of0<T,
- typename executor_binder_check<typename result_of<T()>::type>::type>
- {
- typedef typename result_of<T()>::type type;
- };
-
- } // namespace detail
-
- /// A call wrapper type to bind an executor of type @c Executor to an object of
- /// type @c T.
- template <typename T, typename Executor>
- class executor_binder
- #if !defined(GENERATING_DOCUMENTATION)
- : public detail::executor_binder_result_type<T>,
- public detail::executor_binder_argument_type<T>,
- public detail::executor_binder_argument_types<T>,
- private detail::executor_binder_base<
- T, Executor, uses_executor<T, Executor>::value>
- #endif // !defined(GENERATING_DOCUMENTATION)
- {
- public:
- /// The type of the target object.
- typedef T target_type;
-
- /// The type of the associated executor.
- typedef Executor executor_type;
-
- #if defined(GENERATING_DOCUMENTATION)
- /// The return type if a function.
- /**
- * The type of @c result_type is based on the type @c T of the wrapper's
- * target object:
- *
- * @li if @c T is a pointer to function type, @c result_type is a synonym for
- * the return type of @c T;
- *
- * @li if @c T is a class type with a member type @c result_type, then @c
- * result_type is a synonym for @c T::result_type;
- *
- * @li otherwise @c result_type is not defined.
- */
- typedef see_below result_type;
-
- /// The type of the function's argument.
- /**
- * The type of @c argument_type is based on the type @c T of the wrapper's
- * target object:
- *
- * @li if @c T is a pointer to a function type accepting a single argument,
- * @c argument_type is a synonym for the return type of @c T;
- *
- * @li if @c T is a class type with a member type @c argument_type, then @c
- * argument_type is a synonym for @c T::argument_type;
- *
- * @li otherwise @c argument_type is not defined.
- */
- typedef see_below argument_type;
-
- /// The type of the function's first argument.
- /**
- * The type of @c first_argument_type is based on the type @c T of the
- * wrapper's target object:
- *
- * @li if @c T is a pointer to a function type accepting two arguments, @c
- * first_argument_type is a synonym for the return type of @c T;
- *
- * @li if @c T is a class type with a member type @c first_argument_type,
- * then @c first_argument_type is a synonym for @c T::first_argument_type;
- *
- * @li otherwise @c first_argument_type is not defined.
- */
- typedef see_below first_argument_type;
-
- /// The type of the function's second argument.
- /**
- * The type of @c second_argument_type is based on the type @c T of the
- * wrapper's target object:
- *
- * @li if @c T is a pointer to a function type accepting two arguments, @c
- * second_argument_type is a synonym for the return type of @c T;
- *
- * @li if @c T is a class type with a member type @c first_argument_type,
- * then @c second_argument_type is a synonym for @c T::second_argument_type;
- *
- * @li otherwise @c second_argument_type is not defined.
- */
- typedef see_below second_argument_type;
- #endif // defined(GENERATING_DOCUMENTATION)
-
- /// Construct an executor wrapper for the specified object.
- /**
- * This constructor is only valid if the type @c T is constructible from type
- * @c U.
- */
- template <typename U>
- executor_binder(executor_arg_t, const executor_type& e,
- ASIO_MOVE_ARG(U) u)
- : base_type(e, ASIO_MOVE_CAST(U)(u))
- {
- }
-
- /// Copy constructor.
- executor_binder(const executor_binder& other)
- : base_type(other.get_executor(), other.get())
- {
- }
-
- /// Construct a copy, but specify a different executor.
- executor_binder(executor_arg_t, const executor_type& e,
- const executor_binder& other)
- : base_type(e, other.get())
- {
- }
-
- /// Construct a copy of a different executor wrapper type.
- /**
- * This constructor is only valid if the @c Executor type is constructible
- * from type @c OtherExecutor, and the type @c T is constructible from type
- * @c U.
- */
- template <typename U, typename OtherExecutor>
- executor_binder(const executor_binder<U, OtherExecutor>& other)
- : base_type(other.get_executor(), other.get())
- {
- }
-
- /// Construct a copy of a different executor wrapper type, but specify a
- /// different executor.
- /**
- * This constructor is only valid if the type @c T is constructible from type
- * @c U.
- */
- template <typename U, typename OtherExecutor>
- executor_binder(executor_arg_t, const executor_type& e,
- const executor_binder<U, OtherExecutor>& other)
- : base_type(e, other.get())
- {
- }
-
- #if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
-
- /// Move constructor.
- executor_binder(executor_binder&& other)
- : base_type(ASIO_MOVE_CAST(executor_type)(other.get_executor()),
- ASIO_MOVE_CAST(T)(other.get()))
- {
- }
-
- /// Move construct the target object, but specify a different executor.
- executor_binder(executor_arg_t, const executor_type& e,
- executor_binder&& other)
- : base_type(e, ASIO_MOVE_CAST(T)(other.get()))
- {
- }
-
- /// Move construct from a different executor wrapper type.
- template <typename U, typename OtherExecutor>
- executor_binder(executor_binder<U, OtherExecutor>&& other)
- : base_type(ASIO_MOVE_CAST(OtherExecutor)(other.get_executor()),
- ASIO_MOVE_CAST(U)(other.get()))
- {
- }
-
- /// Move construct from a different executor wrapper type, but specify a
- /// different executor.
- template <typename U, typename OtherExecutor>
- executor_binder(executor_arg_t, const executor_type& e,
- executor_binder<U, OtherExecutor>&& other)
- : base_type(e, ASIO_MOVE_CAST(U)(other.get()))
- {
- }
-
- #endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
-
- /// Destructor.
- ~executor_binder()
- {
- }
-
- /// Obtain a reference to the target object.
- target_type& get() ASIO_NOEXCEPT
- {
- return this->target_;
- }
-
- /// Obtain a reference to the target object.
- const target_type& get() const ASIO_NOEXCEPT
- {
- return this->target_;
- }
-
- /// Obtain the associated executor.
- executor_type get_executor() const ASIO_NOEXCEPT
- {
- return static_cast<const Executor&>(*this);
- }
-
- #if defined(GENERATING_DOCUMENTATION)
-
- template <typename... Args> auto operator()(Args&& ...);
- template <typename... Args> auto operator()(Args&& ...) const;
-
- #elif defined(ASIO_HAS_VARIADIC_TEMPLATES)
-
- /// Forwarding function call operator.
- template <typename... Args>
- typename result_of<T(Args...)>::type operator()(
- ASIO_MOVE_ARG(Args)... args)
- {
- return this->target_(ASIO_MOVE_CAST(Args)(args)...);
- }
-
- /// Forwarding function call operator.
- template <typename... Args>
- typename result_of<T(Args...)>::type operator()(
- ASIO_MOVE_ARG(Args)... args) const
- {
- return this->target_(ASIO_MOVE_CAST(Args)(args)...);
- }
-
- #elif defined(ASIO_HAS_STD_TYPE_TRAITS) && !defined(_MSC_VER)
-
- typename detail::executor_binder_result_of0<T>::type operator()()
- {
- return this->target_();
- }
-
- typename detail::executor_binder_result_of0<T>::type operator()() const
- {
- return this->target_();
- }
-
- #define ASIO_PRIVATE_BIND_EXECUTOR_CALL_DEF(n) \
- template <ASIO_VARIADIC_TPARAMS(n)> \
- typename result_of<T(ASIO_VARIADIC_TARGS(n))>::type operator()( \
- ASIO_VARIADIC_MOVE_PARAMS(n)) \
- { \
- return this->target_(ASIO_VARIADIC_MOVE_ARGS(n)); \
- } \
- \
- template <ASIO_VARIADIC_TPARAMS(n)> \
- typename result_of<T(ASIO_VARIADIC_TARGS(n))>::type 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
-
- #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 enable_if<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 enable_if<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>
- struct handler_type<executor_binder<T, Executor>, Signature>
- {
- typedef executor_binder<
- typename handler_type<T, Signature>::type, Executor> type;
- };
-
- template <typename T, typename Executor>
- class async_result<executor_binder<T, Executor> >
- {
- public:
- typedef typename async_result<T>::type type;
-
- explicit async_result(executor_binder<T, Executor>& b)
- : target_(b.get())
- {
- }
-
- type get()
- {
- return target_.get();
- }
-
- private:
- async_result<T> 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
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