boost/asio/compose.hpp
//
// compose.hpp
// ~~~~~~~~~~~
//
// Copyright (c) 2003-2022 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_COMPOSE_HPP
#define BOOST_ASIO_COMPOSE_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/associated_executor.hpp>
#include <boost/asio/async_result.hpp>
#include <boost/asio/detail/base_from_cancellation_state.hpp>
#include <boost/asio/detail/composed_work.hpp>
#include <boost/asio/detail/handler_alloc_helpers.hpp>
#include <boost/asio/detail/handler_cont_helpers.hpp>
#include <boost/asio/detail/handler_invoke_helpers.hpp>
#include <boost/asio/detail/type_traits.hpp>
#include <boost/asio/detail/variadic_templates.hpp>
#include <boost/asio/detail/push_options.hpp>
namespace boost {
namespace asio {
namespace detail {
#if defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES)
template <typename Impl, typename Work, typename Handler, typename Signature>
class composed_op;
template <typename Impl, typename Work, typename Handler,
typename R, typename... Args>
class composed_op<Impl, Work, Handler, R(Args...)>
#else // defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES)
template <typename Impl, typename Work, typename Handler, typename Signature>
class composed_op
#endif // defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES)
: public base_from_cancellation_state<Handler>
{
public:
template <typename I, typename W, typename H>
composed_op(BOOST_ASIO_MOVE_ARG(I) impl,
BOOST_ASIO_MOVE_ARG(W) work,
BOOST_ASIO_MOVE_ARG(H) handler)
: base_from_cancellation_state<Handler>(
handler, enable_terminal_cancellation()),
impl_(BOOST_ASIO_MOVE_CAST(I)(impl)),
work_(BOOST_ASIO_MOVE_CAST(W)(work)),
handler_(BOOST_ASIO_MOVE_CAST(H)(handler)),
invocations_(0)
{
}
#if defined(BOOST_ASIO_HAS_MOVE)
composed_op(composed_op&& other)
: base_from_cancellation_state<Handler>(
BOOST_ASIO_MOVE_CAST(base_from_cancellation_state<
Handler>)(other)),
impl_(BOOST_ASIO_MOVE_CAST(Impl)(other.impl_)),
work_(BOOST_ASIO_MOVE_CAST(Work)(other.work_)),
handler_(BOOST_ASIO_MOVE_CAST(Handler)(other.handler_)),
invocations_(other.invocations_)
{
}
#endif // defined(BOOST_ASIO_HAS_MOVE)
typedef typename composed_work_guard<
typename Work::head_type>::executor_type io_executor_type;
io_executor_type get_io_executor() const BOOST_ASIO_NOEXCEPT
{
return work_.head_.get_executor();
}
typedef typename associated_executor<Handler, io_executor_type>::type
executor_type;
executor_type get_executor() const BOOST_ASIO_NOEXCEPT
{
return (get_associated_executor)(handler_, work_.head_.get_executor());
}
typedef typename associated_allocator<Handler,
std::allocator<void> >::type allocator_type;
allocator_type get_allocator() const BOOST_ASIO_NOEXCEPT
{
return (get_associated_allocator)(handler_, std::allocator<void>());
}
#if defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES)
template<typename... T>
void operator()(BOOST_ASIO_MOVE_ARG(T)... t)
{
if (invocations_ < ~0u)
++invocations_;
this->get_cancellation_state().slot().clear();
impl_(*this, BOOST_ASIO_MOVE_CAST(T)(t)...);
}
void complete(Args... args)
{
this->work_.reset();
BOOST_ASIO_MOVE_OR_LVALUE(Handler)(this->handler_)(
BOOST_ASIO_MOVE_CAST(Args)(args)...);
}
#else // defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES)
void operator()()
{
if (invocations_ < ~0u)
++invocations_;
this->get_cancellation_state().slot().clear();
impl_(*this);
}
void complete()
{
this->work_.reset();
BOOST_ASIO_MOVE_OR_LVALUE(Handler)(this->handler_)();
}
#define BOOST_ASIO_PRIVATE_COMPOSED_OP_DEF(n) \
template<BOOST_ASIO_VARIADIC_TPARAMS(n)> \
void operator()(BOOST_ASIO_VARIADIC_MOVE_PARAMS(n)) \
{ \
if (invocations_ < ~0u) \
++invocations_; \
this->get_cancellation_state().slot().clear(); \
impl_(*this, BOOST_ASIO_VARIADIC_MOVE_ARGS(n)); \
} \
\
template<BOOST_ASIO_VARIADIC_TPARAMS(n)> \
void complete(BOOST_ASIO_VARIADIC_MOVE_PARAMS(n)) \
{ \
this->work_.reset(); \
BOOST_ASIO_MOVE_OR_LVALUE(Handler)(this->handler_)( \
BOOST_ASIO_VARIADIC_MOVE_ARGS(n)); \
} \
/**/
BOOST_ASIO_VARIADIC_GENERATE(BOOST_ASIO_PRIVATE_COMPOSED_OP_DEF)
#undef BOOST_ASIO_PRIVATE_COMPOSED_OP_DEF
#endif // defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES)
void reset_cancellation_state()
{
base_from_cancellation_state<Handler>::reset_cancellation_state(handler_);
}
template <typename Filter>
void reset_cancellation_state(BOOST_ASIO_MOVE_ARG(Filter) filter)
{
base_from_cancellation_state<Handler>::reset_cancellation_state(handler_,
BOOST_ASIO_MOVE_CAST(Filter)(filter));
}
template <typename InFilter, typename OutFilter>
void reset_cancellation_state(BOOST_ASIO_MOVE_ARG(InFilter) in_filter,
BOOST_ASIO_MOVE_ARG(OutFilter) out_filter)
{
base_from_cancellation_state<Handler>::reset_cancellation_state(handler_,
BOOST_ASIO_MOVE_CAST(InFilter)(in_filter),
BOOST_ASIO_MOVE_CAST(OutFilter)(out_filter));
}
cancellation_type_t cancelled() const BOOST_ASIO_NOEXCEPT
{
return base_from_cancellation_state<Handler>::cancelled();
}
//private:
Impl impl_;
Work work_;
Handler handler_;
unsigned invocations_;
};
template <typename Impl, typename Work, typename Handler, typename Signature>
inline asio_handler_allocate_is_deprecated
asio_handler_allocate(std::size_t size,
composed_op<Impl, Work, Handler, Signature>* this_handler)
{
#if defined(BOOST_ASIO_NO_DEPRECATED)
boost_asio_handler_alloc_helpers::allocate(size, this_handler->handler_);
return asio_handler_allocate_is_no_longer_used();
#else // defined(BOOST_ASIO_NO_DEPRECATED)
return boost_asio_handler_alloc_helpers::allocate(
size, this_handler->handler_);
#endif // defined(BOOST_ASIO_NO_DEPRECATED)
}
template <typename Impl, typename Work, typename Handler, typename Signature>
inline asio_handler_deallocate_is_deprecated
asio_handler_deallocate(void* pointer, std::size_t size,
composed_op<Impl, Work, Handler, Signature>* this_handler)
{
boost_asio_handler_alloc_helpers::deallocate(
pointer, size, this_handler->handler_);
#if defined(BOOST_ASIO_NO_DEPRECATED)
return asio_handler_deallocate_is_no_longer_used();
#endif // defined(BOOST_ASIO_NO_DEPRECATED)
}
template <typename Impl, typename Work, typename Handler, typename Signature>
inline bool asio_handler_is_continuation(
composed_op<Impl, Work, Handler, Signature>* this_handler)
{
return this_handler->invocations_ > 1 ? true
: boost_asio_handler_cont_helpers::is_continuation(
this_handler->handler_);
}
template <typename Function, typename Impl,
typename Work, typename Handler, typename Signature>
inline asio_handler_invoke_is_deprecated
asio_handler_invoke(Function& function,
composed_op<Impl, Work, Handler, Signature>* this_handler)
{
boost_asio_handler_invoke_helpers::invoke(
function, this_handler->handler_);
#if defined(BOOST_ASIO_NO_DEPRECATED)
return asio_handler_invoke_is_no_longer_used();
#endif // defined(BOOST_ASIO_NO_DEPRECATED)
}
template <typename Function, typename Impl,
typename Work, typename Handler, typename Signature>
inline asio_handler_invoke_is_deprecated
asio_handler_invoke(const Function& function,
composed_op<Impl, Work, Handler, Signature>* this_handler)
{
boost_asio_handler_invoke_helpers::invoke(
function, this_handler->handler_);
#if defined(BOOST_ASIO_NO_DEPRECATED)
return asio_handler_invoke_is_no_longer_used();
#endif // defined(BOOST_ASIO_NO_DEPRECATED)
}
template <typename Signature, typename Executors>
class initiate_composed_op
{
public:
typedef typename composed_io_executors<Executors>::head_type executor_type;
template <typename T>
explicit initiate_composed_op(int, BOOST_ASIO_MOVE_ARG(T) executors)
: executors_(BOOST_ASIO_MOVE_CAST(T)(executors))
{
}
executor_type get_executor() const BOOST_ASIO_NOEXCEPT
{
return executors_.head_;
}
template <typename Handler, typename Impl>
void operator()(BOOST_ASIO_MOVE_ARG(Handler) handler,
BOOST_ASIO_MOVE_ARG(Impl) impl) const
{
composed_op<typename decay<Impl>::type, composed_work<Executors>,
typename decay<Handler>::type, Signature>(
BOOST_ASIO_MOVE_CAST(Impl)(impl),
composed_work<Executors>(executors_),
BOOST_ASIO_MOVE_CAST(Handler)(handler))();
}
private:
composed_io_executors<Executors> executors_;
};
template <typename Signature, typename Executors>
inline initiate_composed_op<Signature, Executors> make_initiate_composed_op(
BOOST_ASIO_MOVE_ARG(composed_io_executors<Executors>) executors)
{
return initiate_composed_op<Signature, Executors>(0,
BOOST_ASIO_MOVE_CAST(composed_io_executors<Executors>)(executors));
}
} // namespace detail
#if !defined(GENERATING_DOCUMENTATION)
template <template <typename, typename> class Associator,
typename Impl, typename Work, typename Handler,
typename Signature, typename DefaultCandidate>
struct associator<Associator,
detail::composed_op<Impl, Work, Handler, Signature>,
DefaultCandidate>
: Associator<Handler, DefaultCandidate>
{
static typename Associator<Handler, DefaultCandidate>::type
get(const detail::composed_op<Impl, Work, Handler, Signature>& h)
BOOST_ASIO_NOEXCEPT
{
return Associator<Handler, DefaultCandidate>::get(h.handler_);
}
static BOOST_ASIO_AUTO_RETURN_TYPE_PREFIX2(
typename Associator<Handler, DefaultCandidate>::type)
get(const detail::composed_op<Impl, Work, Handler, Signature>& h,
const DefaultCandidate& c) BOOST_ASIO_NOEXCEPT
BOOST_ASIO_AUTO_RETURN_TYPE_SUFFIX((
Associator<Handler, DefaultCandidate>::get(h.handler_, c)))
{
return Associator<Handler, DefaultCandidate>::get(h.handler_, c);
}
};
#endif // !defined(GENERATING_DOCUMENTATION)
#if defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES) \
|| defined(GENERATING_DOCUMENTATION)
/// Launch an asynchronous operation with a stateful implementation.
/**
* The async_compose function simplifies the implementation of composed
* asynchronous operations automatically wrapping a stateful function object
* with a conforming intermediate completion handler.
*
* @param implementation A function object that contains the implementation of
* the composed asynchronous operation. The first argument to the function
* object is a non-const reference to the enclosing intermediate completion
* handler. The remaining arguments are any arguments that originate from the
* completion handlers of any asynchronous operations performed by the
* implementation.
*
* @param token The completion token.
*
* @param io_objects_or_executors Zero or more I/O objects or I/O executors for
* which outstanding work must be maintained.
*
* @par Example:
*
* @code struct async_echo_implementation
* {
* tcp::socket& socket_;
* boost::asio::mutable_buffer buffer_;
* enum { starting, reading, writing } state_;
*
* template <typename Self>
* void operator()(Self& self,
* boost::system::error_code error = {},
* std::size_t n = 0)
* {
* switch (state_)
* {
* case starting:
* state_ = reading;
* socket_.async_read_some(
* buffer_, std::move(self));
* break;
* case reading:
* if (error)
* {
* self.complete(error, 0);
* }
* else
* {
* state_ = writing;
* boost::asio::async_write(socket_, buffer_,
* boost::asio::transfer_exactly(n),
* std::move(self));
* }
* break;
* case writing:
* self.complete(error, n);
* break;
* }
* }
* };
*
* template <typename CompletionToken>
* auto async_echo(tcp::socket& socket,
* boost::asio::mutable_buffer buffer,
* CompletionToken&& token) ->
* decltype(
* boost::asio::async_compose<CompletionToken,
* void(boost::system::error_code, std::size_t)>(
* std::declval<async_echo_implementation>(),
* token, socket))
* {
* return boost::asio::async_compose<CompletionToken,
* void(boost::system::error_code, std::size_t)>(
* async_echo_implementation{socket, buffer,
* async_echo_implementation::starting},
* token, socket);
* } @endcode
*/
template <typename CompletionToken, typename Signature,
typename Implementation, typename... IoObjectsOrExecutors>
BOOST_ASIO_INITFN_AUTO_RESULT_TYPE_PREFIX(CompletionToken, Signature)
async_compose(BOOST_ASIO_MOVE_ARG(Implementation) implementation,
BOOST_ASIO_NONDEDUCED_MOVE_ARG(CompletionToken) token,
BOOST_ASIO_MOVE_ARG(IoObjectsOrExecutors)... io_objects_or_executors)
BOOST_ASIO_INITFN_AUTO_RESULT_TYPE_SUFFIX((
async_initiate<CompletionToken, Signature>(
detail::make_initiate_composed_op<Signature>(
detail::make_composed_io_executors(
detail::get_composed_io_executor(
BOOST_ASIO_MOVE_CAST(IoObjectsOrExecutors)(
io_objects_or_executors))...)),
token, BOOST_ASIO_MOVE_CAST(Implementation)(implementation))))
{
return async_initiate<CompletionToken, Signature>(
detail::make_initiate_composed_op<Signature>(
detail::make_composed_io_executors(
detail::get_composed_io_executor(
BOOST_ASIO_MOVE_CAST(IoObjectsOrExecutors)(
io_objects_or_executors))...)),
token, BOOST_ASIO_MOVE_CAST(Implementation)(implementation));
}
#else // defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES)
// || defined(GENERATING_DOCUMENTATION)
template <typename CompletionToken, typename Signature, typename Implementation>
BOOST_ASIO_INITFN_AUTO_RESULT_TYPE_PREFIX(CompletionToken, Signature)
async_compose(BOOST_ASIO_MOVE_ARG(Implementation) implementation,
BOOST_ASIO_NONDEDUCED_MOVE_ARG(CompletionToken) token)
BOOST_ASIO_INITFN_AUTO_RESULT_TYPE_SUFFIX((
async_initiate<CompletionToken, Signature>(
detail::make_initiate_composed_op<Signature>(
detail::make_composed_io_executors()),
token, BOOST_ASIO_MOVE_CAST(Implementation)(implementation))))
{
return async_initiate<CompletionToken, Signature>(
detail::make_initiate_composed_op<Signature>(
detail::make_composed_io_executors()),
token, BOOST_ASIO_MOVE_CAST(Implementation)(implementation));
}
# define BOOST_ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR(n) \
BOOST_ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR_##n
# define BOOST_ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR_1 \
detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T1)(x1))
# define BOOST_ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR_2 \
detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T1)(x1)), \
detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T2)(x2))
# define BOOST_ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR_3 \
detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T1)(x1)), \
detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T2)(x2)), \
detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T3)(x3))
# define BOOST_ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR_4 \
detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T1)(x1)), \
detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T2)(x2)), \
detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T3)(x3)), \
detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T4)(x4))
# define BOOST_ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR_5 \
detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T1)(x1)), \
detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T2)(x2)), \
detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T3)(x3)), \
detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T4)(x4)), \
detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T5)(x5))
# define BOOST_ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR_6 \
detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T1)(x1)), \
detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T2)(x2)), \
detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T3)(x3)), \
detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T4)(x4)), \
detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T5)(x5)), \
detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T6)(x6))
# define BOOST_ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR_7 \
detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T1)(x1)), \
detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T2)(x2)), \
detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T3)(x3)), \
detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T4)(x4)), \
detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T5)(x5)), \
detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T6)(x6)), \
detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T7)(x7))
# define BOOST_ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR_8 \
detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T1)(x1)), \
detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T2)(x2)), \
detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T3)(x3)), \
detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T4)(x4)), \
detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T5)(x5)), \
detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T6)(x6)), \
detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T7)(x7)), \
detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T8)(x8))
#define BOOST_ASIO_PRIVATE_ASYNC_COMPOSE_DEF(n) \
template <typename CompletionToken, typename Signature, \
typename Implementation, BOOST_ASIO_VARIADIC_TPARAMS(n)> \
BOOST_ASIO_INITFN_AUTO_RESULT_TYPE_PREFIX(CompletionToken, Signature) \
async_compose(BOOST_ASIO_MOVE_ARG(Implementation) implementation, \
BOOST_ASIO_NONDEDUCED_MOVE_ARG(CompletionToken) token, \
BOOST_ASIO_VARIADIC_MOVE_PARAMS(n)) \
BOOST_ASIO_INITFN_AUTO_RESULT_TYPE_SUFFIX(( \
async_initiate<CompletionToken, Signature>( \
detail::make_initiate_composed_op<Signature>( \
detail::make_composed_io_executors( \
BOOST_ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR(n))), \
token, BOOST_ASIO_MOVE_CAST(Implementation)(implementation)))) \
{ \
return async_initiate<CompletionToken, Signature>( \
detail::make_initiate_composed_op<Signature>( \
detail::make_composed_io_executors( \
BOOST_ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR(n))), \
token, BOOST_ASIO_MOVE_CAST(Implementation)(implementation)); \
} \
/**/
BOOST_ASIO_VARIADIC_GENERATE(BOOST_ASIO_PRIVATE_ASYNC_COMPOSE_DEF)
#undef BOOST_ASIO_PRIVATE_ASYNC_COMPOSE_DEF
#undef BOOST_ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR
#undef BOOST_ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR_1
#undef BOOST_ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR_2
#undef BOOST_ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR_3
#undef BOOST_ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR_4
#undef BOOST_ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR_5
#undef BOOST_ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR_6
#undef BOOST_ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR_7
#undef BOOST_ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR_8
#endif // defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES)
// || defined(GENERATING_DOCUMENTATION)
} // namespace asio
} // namespace boost
#include <boost/asio/detail/pop_options.hpp>
#endif // BOOST_ASIO_COMPOSE_HPP