boost/asio/bind_immediate_executor.hpp
//
// bind_immediate_executor.hpp
// ~~~~~~~~~~~~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2024 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 BOOST_ASIO_BIND_IMMEDIATE_EXECUTOR_HPP
#define BOOST_ASIO_BIND_IMMEDIATE_EXECUTOR_HPP
#if defined(_MSC_VER) && (_MSC_VER >= 1200)
# pragma once
#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
#include <boost/asio/detail/config.hpp>
#include <boost/asio/detail/type_traits.hpp>
#include <boost/asio/associated_immediate_executor.hpp>
#include <boost/asio/associator.hpp>
#include <boost/asio/async_result.hpp>
#include <boost/asio/detail/push_options.hpp>
namespace boost {
namespace asio {
namespace detail {
// Helper to automatically define nested typedef result_type.
template <typename T, typename = void>
struct immediate_executor_binder_result_type
{
protected:
typedef void result_type_or_void;
};
template <typename T>
struct immediate_executor_binder_result_type<T, void_t<typename T::result_type>>
{
typedef typename T::result_type result_type;
protected:
typedef result_type result_type_or_void;
};
template <typename R>
struct immediate_executor_binder_result_type<R(*)()>
{
typedef R result_type;
protected:
typedef result_type result_type_or_void;
};
template <typename R>
struct immediate_executor_binder_result_type<R(&)()>
{
typedef R result_type;
protected:
typedef result_type result_type_or_void;
};
template <typename R, typename A1>
struct immediate_executor_binder_result_type<R(*)(A1)>
{
typedef R result_type;
protected:
typedef result_type result_type_or_void;
};
template <typename R, typename A1>
struct immediate_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 immediate_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 immediate_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 immediate_executor_binder_argument_type {};
template <typename T>
struct immediate_executor_binder_argument_type<T,
void_t<typename T::argument_type>>
{
typedef typename T::argument_type argument_type;
};
template <typename R, typename A1>
struct immediate_executor_binder_argument_type<R(*)(A1)>
{
typedef A1 argument_type;
};
template <typename R, typename A1>
struct immediate_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 immediate_executor_binder_argument_types {};
template <typename T>
struct immediate_executor_binder_argument_types<T,
void_t<typename T::first_argument_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 immediate_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 immediate_executor_binder_argument_type<R(&)(A1, A2)>
{
typedef A1 first_argument_type;
typedef A2 second_argument_type;
};
} // namespace detail
/// A call wrapper type to bind a immediate executor of type @c Executor
/// to an object of type @c T.
template <typename T, typename Executor>
class immediate_executor_binder
#if !defined(GENERATING_DOCUMENTATION)
: public detail::immediate_executor_binder_result_type<T>,
public detail::immediate_executor_binder_argument_type<T>,
public detail::immediate_executor_binder_argument_types<T>
#endif // !defined(GENERATING_DOCUMENTATION)
{
public:
/// The type of the target object.
typedef T target_type;
/// The type of the associated immediate executor.
typedef Executor immediate_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 a immediate 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>
immediate_executor_binder(const immediate_executor_type& e,
U&& u)
: executor_(e),
target_(static_cast<U&&>(u))
{
}
/// Copy constructor.
immediate_executor_binder(const immediate_executor_binder& other)
: executor_(other.get_immediate_executor()),
target_(other.get())
{
}
/// Construct a copy, but specify a different immediate executor.
immediate_executor_binder(const immediate_executor_type& e,
const immediate_executor_binder& other)
: executor_(e),
target_(other.get())
{
}
/// Construct a copy of a different immediate 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>
immediate_executor_binder(
const immediate_executor_binder<U, OtherExecutor>& other,
constraint_t<is_constructible<Executor, OtherExecutor>::value> = 0,
constraint_t<is_constructible<T, U>::value> = 0)
: executor_(other.get_immediate_executor()),
target_(other.get())
{
}
/// Construct a copy of a different immediate executor wrapper type, but
/// specify a different immediate executor.
/**
* This constructor is only valid if the type @c T is constructible from type
* @c U.
*/
template <typename U, typename OtherExecutor>
immediate_executor_binder(const immediate_executor_type& e,
const immediate_executor_binder<U, OtherExecutor>& other,
constraint_t<is_constructible<T, U>::value> = 0)
: executor_(e),
target_(other.get())
{
}
/// Move constructor.
immediate_executor_binder(immediate_executor_binder&& other)
: executor_(static_cast<immediate_executor_type&&>(
other.get_immediate_executor())),
target_(static_cast<T&&>(other.get()))
{
}
/// Move construct the target object, but specify a different immediate
/// executor.
immediate_executor_binder(const immediate_executor_type& e,
immediate_executor_binder&& other)
: executor_(e),
target_(static_cast<T&&>(other.get()))
{
}
/// Move construct from a different immediate executor wrapper type.
template <typename U, typename OtherExecutor>
immediate_executor_binder(
immediate_executor_binder<U, OtherExecutor>&& other,
constraint_t<is_constructible<Executor, OtherExecutor>::value> = 0,
constraint_t<is_constructible<T, U>::value> = 0)
: executor_(static_cast<OtherExecutor&&>(
other.get_immediate_executor())),
target_(static_cast<U&&>(other.get()))
{
}
/// Move construct from a different immediate executor wrapper type, but
/// specify a different immediate executor.
template <typename U, typename OtherExecutor>
immediate_executor_binder(const immediate_executor_type& e,
immediate_executor_binder<U, OtherExecutor>&& other,
constraint_t<is_constructible<T, U>::value> = 0)
: executor_(e),
target_(static_cast<U&&>(other.get()))
{
}
/// Destructor.
~immediate_executor_binder()
{
}
/// Obtain a reference to the target object.
target_type& get() noexcept
{
return target_;
}
/// Obtain a reference to the target object.
const target_type& get() const noexcept
{
return target_;
}
/// Obtain the associated immediate executor.
immediate_executor_type get_immediate_executor() const noexcept
{
return executor_;
}
/// Forwarding function call operator.
template <typename... Args>
result_of_t<T(Args...)> operator()(Args&&... args)
{
return target_(static_cast<Args&&>(args)...);
}
/// Forwarding function call operator.
template <typename... Args>
result_of_t<T(Args...)> operator()(Args&&... args) const
{
return target_(static_cast<Args&&>(args)...);
}
private:
Executor executor_;
T target_;
};
/// Associate an object of type @c T with a immediate executor of type
/// @c Executor.
template <typename Executor, typename T>
BOOST_ASIO_NODISCARD inline immediate_executor_binder<decay_t<T>, Executor>
bind_immediate_executor(const Executor& e, T&& t)
{
return immediate_executor_binder<
decay_t<T>, Executor>(
e, static_cast<T&&>(t));
}
#if !defined(GENERATING_DOCUMENTATION)
namespace detail {
template <typename TargetAsyncResult, typename Executor, typename = void>
class immediate_executor_binder_completion_handler_async_result
{
public:
template <typename T>
explicit immediate_executor_binder_completion_handler_async_result(T&)
{
}
};
template <typename TargetAsyncResult, typename Executor>
class immediate_executor_binder_completion_handler_async_result<
TargetAsyncResult, Executor,
void_t<
typename TargetAsyncResult::completion_handler_type
>>
{
private:
TargetAsyncResult target_;
public:
typedef immediate_executor_binder<
typename TargetAsyncResult::completion_handler_type, Executor>
completion_handler_type;
explicit immediate_executor_binder_completion_handler_async_result(
typename TargetAsyncResult::completion_handler_type& handler)
: target_(handler)
{
}
auto get() -> decltype(target_.get())
{
return target_.get();
}
};
template <typename TargetAsyncResult, typename = void>
struct immediate_executor_binder_async_result_return_type
{
};
template <typename TargetAsyncResult>
struct immediate_executor_binder_async_result_return_type<
TargetAsyncResult,
void_t<
typename TargetAsyncResult::return_type
>>
{
typedef typename TargetAsyncResult::return_type return_type;
};
} // namespace detail
template <typename T, typename Executor, typename Signature>
class async_result<immediate_executor_binder<T, Executor>, Signature> :
public detail::immediate_executor_binder_completion_handler_async_result<
async_result<T, Signature>, Executor>,
public detail::immediate_executor_binder_async_result_return_type<
async_result<T, Signature>>
{
public:
explicit async_result(immediate_executor_binder<T, Executor>& b)
: detail::immediate_executor_binder_completion_handler_async_result<
async_result<T, Signature>, Executor>(b.get())
{
}
template <typename Initiation>
struct init_wrapper
{
template <typename Init>
init_wrapper(const Executor& e, Init&& init)
: executor_(e),
initiation_(static_cast<Init&&>(init))
{
}
template <typename Handler, typename... Args>
void operator()(Handler&& handler, Args&&... args)
{
static_cast<Initiation&&>(initiation_)(
immediate_executor_binder<
decay_t<Handler>, Executor>(
executor_, static_cast<Handler&&>(handler)),
static_cast<Args&&>(args)...);
}
template <typename Handler, typename... Args>
void operator()(Handler&& handler, Args&&... args) const
{
initiation_(
immediate_executor_binder<
decay_t<Handler>, Executor>(
executor_, static_cast<Handler&&>(handler)),
static_cast<Args&&>(args)...);
}
Executor executor_;
Initiation initiation_;
};
template <typename Initiation, typename RawCompletionToken, typename... Args>
static auto initiate(Initiation&& initiation,
RawCompletionToken&& token, Args&&... args)
-> decltype(
async_initiate<T, Signature>(
declval<init_wrapper<decay_t<Initiation>>>(),
token.get(), static_cast<Args&&>(args)...))
{
return async_initiate<T, Signature>(
init_wrapper<decay_t<Initiation>>(
token.get_immediate_executor(),
static_cast<Initiation&&>(initiation)),
token.get(), static_cast<Args&&>(args)...);
}
private:
async_result(const async_result&) = delete;
async_result& operator=(const async_result&) = delete;
async_result<T, Signature> target_;
};
template <template <typename, typename> class Associator,
typename T, typename Executor, typename DefaultCandidate>
struct associator<Associator,
immediate_executor_binder<T, Executor>,
DefaultCandidate>
: Associator<T, DefaultCandidate>
{
static typename Associator<T, DefaultCandidate>::type get(
const immediate_executor_binder<T, Executor>& b) noexcept
{
return Associator<T, DefaultCandidate>::get(b.get());
}
static auto get(const immediate_executor_binder<T, Executor>& b,
const DefaultCandidate& c) noexcept
-> decltype(Associator<T, DefaultCandidate>::get(b.get(), c))
{
return Associator<T, DefaultCandidate>::get(b.get(), c);
}
};
template <typename T, typename Executor, typename Executor1>
struct associated_immediate_executor<
immediate_executor_binder<T, Executor>,
Executor1>
{
typedef Executor type;
static auto get(const immediate_executor_binder<T, Executor>& b,
const Executor1& = Executor1()) noexcept
-> decltype(b.get_immediate_executor())
{
return b.get_immediate_executor();
}
};
#endif // !defined(GENERATING_DOCUMENTATION)
} // namespace asio
} // namespace boost
#include <boost/asio/detail/pop_options.hpp>
#endif // BOOST_ASIO_BIND_IMMEDIATE_EXECUTOR_HPP