Edit: /usr/include/boost/asio/query.hpp (8323B)
//
// query.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_QUERY_HPP
#define BOOST_ASIO_QUERY_HPP
#if defined(_MSC_VER) && (_MSC_VER >= 1200)
# pragma once
#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
#include
#include
#include
#include
#include
#include
#include
#if defined(GENERATING_DOCUMENTATION)
namespace boost {
namespace asio {
/// A customisation point that queries the value of a property.
/**
* The name query denotes a customization point object. The
* expression boost::asio::query(E, P) for some
* subexpressions E and P (with types T =
* decay_t and Prop = decay_t) is
* expression-equivalent to:
*
* @li If is_applicable_property_v is not a well-formed
* constant expression with value true, boost::asio::query(E,
* P) is ill-formed.
*
* @li Otherwise, Prop::template static_query_v if the expression
* Prop::template static_query_v is a well-formed constant
* expression.
*
* @li Otherwise, (E).query(P) if the expression
* (E).query(P) is well-formed.
*
* @li Otherwise, query(E, P) if the expression
* query(E, P) is a valid expression with overload
* resolution performed in a context that does not include the declaration
* of the query customization point object.
*
* @li Otherwise, boost::asio::query(E, P) is ill-formed.
*/
inline constexpr unspecified query = unspecified;
/// A type trait that determines whether a @c query expression is well-formed.
/**
* Class template @c can_query is a trait that is derived from
* @c true_type if the expression boost::asio::query(std::declval(),
* std::declval()) is well formed; otherwise @c false_type.
*/
template
struct can_query :
integral_constant
{
};
/// A type trait that determines whether a @c query expression will
/// not throw.
/**
* Class template @c is_nothrow_query is a trait that is derived from
* @c true_type if the expression boost::asio::query(std::declval(),
* std::declval()) is @c noexcept; otherwise @c false_type.
*/
template
struct is_nothrow_query :
integral_constant
{
};
/// A type trait that determines the result type of a @c query expression.
/**
* Class template @c query_result is a trait that determines the result
* type of the expression boost::asio::query(std::declval(),
* std::declval()).
*/
template
struct query_result
{
/// The result of the @c query expression.
typedef automatically_determined type;
};
} // namespace asio
} // namespace boost
#else // defined(GENERATING_DOCUMENTATION)
namespace asio_query_fn {
using boost::asio::decay;
using boost::asio::declval;
using boost::asio::enable_if;
using boost::asio::is_applicable_property;
using boost::asio::traits::query_free;
using boost::asio::traits::query_member;
using boost::asio::traits::static_query;
void query();
enum overload_type
{
static_value,
call_member,
call_free,
ill_formed
};
template
struct call_traits
{
BOOST_ASIO_STATIC_CONSTEXPR(overload_type, overload = ill_formed);
BOOST_ASIO_STATIC_CONSTEXPR(bool, is_noexcept = false);
typedef void result_type;
};
template
struct call_traits::type,
typename decay::type
>::value
&&
static_query::is_valid
)
>::type> :
static_query
{
BOOST_ASIO_STATIC_CONSTEXPR(overload_type, overload = static_value);
};
template
struct call_traits::type,
typename decay::type
>::value
&&
!static_query::is_valid
&&
query_member::is_valid
)
>::type> :
query_member
{
BOOST_ASIO_STATIC_CONSTEXPR(overload_type, overload = call_member);
};
template
struct call_traits::type,
typename decay::type
>::value
&&
!static_query::is_valid
&&
!query_member::is_valid
&&
query_free::is_valid
)
>::type> :
query_free
{
BOOST_ASIO_STATIC_CONSTEXPR(overload_type, overload = call_free);
};
struct impl
{
template
BOOST_ASIO_NODISCARD BOOST_ASIO_CONSTEXPR typename enable_if<
call_traits::overload == static_value,
typename call_traits::result_type
>::type
operator()(
BOOST_ASIO_MOVE_ARG(T),
BOOST_ASIO_MOVE_ARG(Property)) const
BOOST_ASIO_NOEXCEPT_IF((
call_traits::is_noexcept))
{
return static_query<
typename decay::type,
typename decay::type
>::value();
}
template
BOOST_ASIO_NODISCARD BOOST_ASIO_CONSTEXPR typename enable_if<
call_traits::overload == call_member,
typename call_traits::result_type
>::type
operator()(
BOOST_ASIO_MOVE_ARG(T) t,
BOOST_ASIO_MOVE_ARG(Property) p) const
BOOST_ASIO_NOEXCEPT_IF((
call_traits::is_noexcept))
{
return BOOST_ASIO_MOVE_CAST(T)(t).query(BOOST_ASIO_MOVE_CAST(Property)(p));
}
template
BOOST_ASIO_NODISCARD BOOST_ASIO_CONSTEXPR typename enable_if<
call_traits::overload == call_free,
typename call_traits::result_type
>::type
operator()(
BOOST_ASIO_MOVE_ARG(T) t,
BOOST_ASIO_MOVE_ARG(Property) p) const
BOOST_ASIO_NOEXCEPT_IF((
call_traits::is_noexcept))
{
return query(BOOST_ASIO_MOVE_CAST(T)(t), BOOST_ASIO_MOVE_CAST(Property)(p));
}
};
template
struct static_instance
{
static const T instance;
};
template
const T static_instance::instance = {};
} // namespace asio_query_fn
namespace boost {
namespace asio {
namespace {
static BOOST_ASIO_CONSTEXPR const asio_query_fn::impl&
query = asio_query_fn::static_instance<>::instance;
} // namespace
template
struct can_query :
integral_constant::overload !=
asio_query_fn::ill_formed>
{
};
#if defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES)
template
constexpr bool can_query_v
= can_query::value;
#endif // defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES)
template
struct is_nothrow_query :
integral_constant::is_noexcept>
{
};
#if defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES)
template
constexpr bool is_nothrow_query_v
= is_nothrow_query::value;
#endif // defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES)
template
struct query_result
{
typedef typename asio_query_fn::call_traits<
T, void(Property)>::result_type type;
};
} // namespace asio
} // namespace boost
#endif // defined(GENERATING_DOCUMENTATION)
#include
#endif // BOOST_ASIO_QUERY_HPP