boost/asio/execution/allocator.hpp
//
// execution/allocator.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_EXECUTION_ALLOCATOR_HPP
#define BOOST_ASIO_EXECUTION_ALLOCATOR_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/execution/executor.hpp>
#include <boost/asio/is_applicable_property.hpp>
#include <boost/asio/traits/query_static_constexpr_member.hpp>
#include <boost/asio/traits/static_query.hpp>
#include <boost/asio/detail/push_options.hpp>
namespace boost {
namespace asio {
#if defined(GENERATING_DOCUMENTATION)
namespace execution {
/// A property to describe which allocator an executor will use to allocate the
/// memory required to store a submitted function object.
template <typename ProtoAllocator>
struct allocator_t
{
/// The allocator_t property applies to executors.
template <typename T>
static constexpr bool is_applicable_property_v = is_executor_v<T>;
/// The allocator_t property can be required.
static constexpr bool is_requirable = true;
/// The allocator_t property can be preferred.
static constexpr bool is_preferable = true;
/// Default constructor.
constexpr allocator_t();
/// Obtain the allocator stored in the allocator_t property object.
/**
* Present only if @c ProtoAllocator is non-void.
*/
constexpr ProtoAllocator value() const;
/// Create an allocator_t object with a different allocator.
/**
* Present only if @c ProtoAllocator is void.
*/
template <typename OtherAllocator>
allocator_t<OtherAllocator operator()(const OtherAllocator& a);
};
/// A special value used for accessing the allocator_t property.
constexpr allocator_t<void> allocator;
} // namespace execution
#else // defined(GENERATING_DOCUMENTATION)
namespace execution {
template <typename ProtoAllocator>
struct allocator_t
{
#if defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES)
template <typename T>
static constexpr bool is_applicable_property_v = is_executor<T>::value;
#endif // defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES)
static constexpr bool is_requirable = true;
static constexpr bool is_preferable = true;
template <typename T>
struct static_proxy
{
#if defined(BOOST_ASIO_HAS_DEDUCED_QUERY_STATIC_CONSTEXPR_MEMBER_TRAIT)
struct type
{
template <typename P>
static constexpr auto query(P&& p)
noexcept(
noexcept(
conditional_t<true, T, P>::query(static_cast<P&&>(p))
)
)
-> decltype(
conditional_t<true, T, P>::query(static_cast<P&&>(p))
)
{
return T::query(static_cast<P&&>(p));
}
};
#else // defined(BOOST_ASIO_HAS_DEDUCED_QUERY_STATIC_CONSTEXPR_MEMBER_TRAIT)
typedef T type;
#endif // defined(BOOST_ASIO_HAS_DEDUCED_QUERY_STATIC_CONSTEXPR_MEMBER_TRAIT)
};
template <typename T>
struct query_static_constexpr_member :
traits::query_static_constexpr_member<
typename static_proxy<T>::type, allocator_t> {};
#if defined(BOOST_ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) \
&& defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES)
template <typename T>
static constexpr typename query_static_constexpr_member<T>::result_type
static_query()
noexcept(query_static_constexpr_member<T>::is_noexcept)
{
return query_static_constexpr_member<T>::value();
}
template <typename E, typename T = decltype(allocator_t::static_query<E>())>
static constexpr const T static_query_v = allocator_t::static_query<E>();
#endif // defined(BOOST_ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT)
// && defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES)
constexpr ProtoAllocator value() const
{
return a_;
}
private:
friend struct allocator_t<void>;
explicit constexpr allocator_t(const ProtoAllocator& a)
: a_(a)
{
}
ProtoAllocator a_;
};
#if defined(BOOST_ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) \
&& defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES)
template <typename ProtoAllocator> template <typename E, typename T>
const T allocator_t<ProtoAllocator>::static_query_v;
#endif // defined(BOOST_ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT)
// && defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES)
template <>
struct allocator_t<void>
{
#if defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES)
template <typename T>
static constexpr bool is_applicable_property_v = is_executor<T>::value;
#endif // defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES)
static constexpr bool is_requirable = true;
static constexpr bool is_preferable = true;
constexpr allocator_t()
{
}
template <typename T>
struct static_proxy
{
#if defined(BOOST_ASIO_HAS_DEDUCED_QUERY_STATIC_CONSTEXPR_MEMBER_TRAIT)
struct type
{
template <typename P>
static constexpr auto query(P&& p)
noexcept(
noexcept(
conditional_t<true, T, P>::query(static_cast<P&&>(p))
)
)
-> decltype(
conditional_t<true, T, P>::query(static_cast<P&&>(p))
)
{
return T::query(static_cast<P&&>(p));
}
};
#else // defined(BOOST_ASIO_HAS_DEDUCED_QUERY_STATIC_CONSTEXPR_MEMBER_TRAIT)
typedef T type;
#endif // defined(BOOST_ASIO_HAS_DEDUCED_QUERY_STATIC_CONSTEXPR_MEMBER_TRAIT)
};
template <typename T>
struct query_static_constexpr_member :
traits::query_static_constexpr_member<
typename static_proxy<T>::type, allocator_t> {};
#if defined(BOOST_ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) \
&& defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES)
template <typename T>
static constexpr typename query_static_constexpr_member<T>::result_type
static_query()
noexcept(query_static_constexpr_member<T>::is_noexcept)
{
return query_static_constexpr_member<T>::value();
}
template <typename E, typename T = decltype(allocator_t::static_query<E>())>
static constexpr const T static_query_v = allocator_t::static_query<E>();
#endif // defined(BOOST_ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT)
// && defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES)
template <typename OtherProtoAllocator>
constexpr allocator_t<OtherProtoAllocator> operator()(
const OtherProtoAllocator& a) const
{
return allocator_t<OtherProtoAllocator>(a);
}
};
#if defined(BOOST_ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) \
&& defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES)
template <typename E, typename T>
const T allocator_t<void>::static_query_v;
#endif // defined(BOOST_ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT)
// && defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES)
BOOST_ASIO_INLINE_VARIABLE constexpr allocator_t<void> allocator;
} // namespace execution
#if !defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES)
template <typename T, typename ProtoAllocator>
struct is_applicable_property<T, execution::allocator_t<ProtoAllocator>>
: integral_constant<bool, execution::is_executor<T>::value>
{
};
#endif // !defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES)
namespace traits {
#if !defined(BOOST_ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) \
|| !defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES)
template <typename T, typename ProtoAllocator>
struct static_query<T, execution::allocator_t<ProtoAllocator>,
enable_if_t<
execution::allocator_t<ProtoAllocator>::template
query_static_constexpr_member<T>::is_valid
>>
{
static constexpr bool is_valid = true;
static constexpr bool is_noexcept = true;
typedef typename execution::allocator_t<ProtoAllocator>::template
query_static_constexpr_member<T>::result_type result_type;
static constexpr result_type value()
{
return execution::allocator_t<ProtoAllocator>::template
query_static_constexpr_member<T>::value();
}
};
#endif // !defined(BOOST_ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT)
// || !defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES)
} // namespace traits
#endif // defined(GENERATING_DOCUMENTATION)
} // namespace asio
} // namespace boost
#include <boost/asio/detail/pop_options.hpp>
#endif // BOOST_ASIO_EXECUTION_ALLOCATOR_HPP