Edit: /usr/include/boost/asio/use_awaitable.hpp (5821B)
//
// use_awaitable.hpp
// ~~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2020 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_USE_AWAITABLE_HPP
#define BOOST_ASIO_USE_AWAITABLE_HPP
#if defined(_MSC_VER) && (_MSC_VER >= 1200)
# pragma once
#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
#include
#if defined(BOOST_ASIO_HAS_CO_AWAIT) || defined(GENERATING_DOCUMENTATION)
#include
#include
#if defined(BOOST_ASIO_ENABLE_HANDLER_TRACKING)
# if defined(BOOST_ASIO_HAS_SOURCE_LOCATION)
# include
# endif // defined(BOOST_ASIO_HAS_SOURCE_LOCATION)
#endif // defined(BOOST_ASIO_ENABLE_HANDLER_TRACKING)
#include
namespace boost {
namespace asio {
/// A completion token that represents the currently executing coroutine.
/**
* The @c use_awaitable_t class, with its value @c use_awaitable, is used to
* represent the currently executing coroutine. This completion token may be
* passed as a handler to an asynchronous operation. For example:
*
* @code awaitable my_coroutine()
* {
* std::size_t n = co_await my_socket.async_read_some(buffer, use_awaitable);
* ...
* } @endcode
*
* When used with co_await, the initiating function (@c async_read_some in the
* above example) suspends the current coroutine. The coroutine is resumed when
* the asynchronous operation completes, and the result of the operation is
* returned.
*/
template
struct use_awaitable_t
{
/// Default constructor.
BOOST_ASIO_CONSTEXPR use_awaitable_t(
#if defined(BOOST_ASIO_ENABLE_HANDLER_TRACKING)
# if defined(BOOST_ASIO_HAS_SOURCE_LOCATION)
detail::source_location location = detail::source_location::current()
# endif // defined(BOOST_ASIO_HAS_SOURCE_LOCATION)
#endif // defined(BOOST_ASIO_ENABLE_HANDLER_TRACKING)
)
#if defined(BOOST_ASIO_ENABLE_HANDLER_TRACKING)
# if defined(BOOST_ASIO_HAS_SOURCE_LOCATION)
: file_name_(location.file_name()),
line_(location.line()),
function_name_(location.function_name())
# else // defined(BOOST_ASIO_HAS_SOURCE_LOCATION)
: file_name_(0),
line_(0),
function_name_(0)
# endif // defined(BOOST_ASIO_HAS_SOURCE_LOCATION)
#endif // defined(BOOST_ASIO_ENABLE_HANDLER_TRACKING)
{
}
/// Constructor used to specify file name, line, and function name.
BOOST_ASIO_CONSTEXPR use_awaitable_t(const char* file_name,
int line, const char* function_name)
#if defined(BOOST_ASIO_ENABLE_HANDLER_TRACKING)
: file_name_(file_name),
line_(line),
function_name_(function_name)
#endif // defined(BOOST_ASIO_ENABLE_HANDLER_TRACKING)
{
#if !defined(BOOST_ASIO_ENABLE_HANDLER_TRACKING)
(void)file_name;
(void)line;
(void)function_name;
#endif // !defined(BOOST_ASIO_ENABLE_HANDLER_TRACKING)
}
/// Adapts an executor to add the @c use_awaitable_t completion token as the
/// default.
template
struct executor_with_default : InnerExecutor
{
/// Specify @c use_awaitable_t as the default completion token type.
typedef use_awaitable_t default_completion_token_type;
/// Construct the adapted executor from the inner executor type.
executor_with_default(const InnerExecutor& ex) BOOST_ASIO_NOEXCEPT
: InnerExecutor(ex)
{
}
/// Convert the specified executor to the inner executor type, then use
/// that to construct the adapted executor.
template
executor_with_default(const OtherExecutor& ex,
typename enable_if<
is_convertible::value
>::type* = 0) BOOST_ASIO_NOEXCEPT
: InnerExecutor(ex)
{
}
};
/// Type alias to adapt an I/O object to use @c use_awaitable_t as its
/// default completion token type.
#if defined(BOOST_ASIO_HAS_ALIAS_TEMPLATES) \
|| defined(GENERATING_DOCUMENTATION)
template
using as_default_on_t = typename T::template rebind_executor<
executor_with_default >::other;
#endif // defined(BOOST_ASIO_HAS_ALIAS_TEMPLATES)
// || defined(GENERATING_DOCUMENTATION)
/// Function helper to adapt an I/O object to use @c use_awaitable_t as its
/// default completion token type.
template
static typename decay::type::template rebind_executor<
executor_with_default::type::executor_type>
>::other
as_default_on(BOOST_ASIO_MOVE_ARG(T) object)
{
return typename decay::type::template rebind_executor<
executor_with_default::type::executor_type>
>::other(BOOST_ASIO_MOVE_CAST(T)(object));
}
#if defined(BOOST_ASIO_ENABLE_HANDLER_TRACKING)
const char* file_name_;
int line_;
const char* function_name_;
#endif // defined(BOOST_ASIO_ENABLE_HANDLER_TRACKING)
};
/// A completion token object that represents the currently executing coroutine.
/**
* See the documentation for boost::asio::use_awaitable_t for a usage example.
*/
#if defined(GENERATING_DOCUMENTATION)
constexpr use_awaitable_t<> use_awaitable;
#elif defined(BOOST_ASIO_HAS_CONSTEXPR)
constexpr use_awaitable_t<> use_awaitable(0, 0, 0);
#elif defined(BOOST_ASIO_MSVC)
__declspec(selectany) use_awaitable_t<> use_awaitable(0, 0, 0);
#endif
} // namespace asio
} // namespace boost
#include
#include
#endif // defined(BOOST_ASIO_HAS_CO_AWAIT) || defined(GENERATING_DOCUMENTATION)
#endif // BOOST_ASIO_USE_AWAITABLE_HPP