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// -*- C++ -*-
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef _LIBCPP___FUNCTIONAL_PERFECT_FORWARD_H
#define _LIBCPP___FUNCTIONAL_PERFECT_FORWARD_H
#include <__config>
#include <__utility/declval.h>
#include <__utility/forward.h>
#include <__utility/move.h>
#include <tuple>
#include <type_traits>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_BEGIN_NAMESPACE_STD
#if _LIBCPP_STD_VER > 14
template <class _Op, class _Indices, class ..._Bound>
struct __perfect_forward_impl;
template <class _Op, size_t ..._Idx, class ..._Bound>
struct __perfect_forward_impl<_Op, index_sequence<_Idx...>, _Bound...> {
private:
tuple<_Bound...> __bound_;
public:
template <class ..._BoundArgs, class = enable_if_t<
is_constructible_v<tuple<_Bound...>, _BoundArgs&&...>
>>
explicit constexpr __perfect_forward_impl(_BoundArgs&& ...__bound)
: __bound_(_VSTD::forward<_BoundArgs>(__bound)...)
{ }
__perfect_forward_impl(__perfect_forward_impl const&) = default;
__perfect_forward_impl(__perfect_forward_impl&&) = default;
__perfect_forward_impl& operator=(__perfect_forward_impl const&) = default;
__perfect_forward_impl& operator=(__perfect_forward_impl&&) = default;
template <class ..._Args, class = enable_if_t<is_invocable_v<_Op, _Bound&..., _Args...>>>
_LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Args&&... __args) &
noexcept(noexcept(_Op()(_VSTD::get<_Idx>(__bound_)..., _VSTD::forward<_Args>(__args)...)))
-> decltype( _Op()(_VSTD::get<_Idx>(__bound_)..., _VSTD::forward<_Args>(__args)...))
{ return _Op()(_VSTD::get<_Idx>(__bound_)..., _VSTD::forward<_Args>(__args)...); }
template <class ..._Args, class = enable_if_t<!is_invocable_v<_Op, _Bound&..., _Args...>>>
auto operator()(_Args&&...) & = delete;
template <class ..._Args, class = enable_if_t<is_invocable_v<_Op, _Bound const&..., _Args...>>>
_LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Args&&... __args) const&
noexcept(noexcept(_Op()(_VSTD::get<_Idx>(__bound_)..., _VSTD::forward<_Args>(__args)...)))
-> decltype( _Op()(_VSTD::get<_Idx>(__bound_)..., _VSTD::forward<_Args>(__args)...))
{ return _Op()(_VSTD::get<_Idx>(__bound_)..., _VSTD::forward<_Args>(__args)...); }
template <class ..._Args, class = enable_if_t<!is_invocable_v<_Op, _Bound const&..., _Args...>>>
auto operator()(_Args&&...) const& = delete;
template <class ..._Args, class = enable_if_t<is_invocable_v<_Op, _Bound..., _Args...>>>
_LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Args&&... __args) &&
noexcept(noexcept(_Op()(_VSTD::get<_Idx>(_VSTD::move(__bound_))..., _VSTD::forward<_Args>(__args)...)))
-> decltype( _Op()(_VSTD::get<_Idx>(_VSTD::move(__bound_))..., _VSTD::forward<_Args>(__args)...))
{ return _Op()(_VSTD::get<_Idx>(_VSTD::move(__bound_))..., _VSTD::forward<_Args>(__args)...); }
template <class ..._Args, class = enable_if_t<!is_invocable_v<_Op, _Bound..., _Args...>>>
auto operator()(_Args&&...) && = delete;
template <class ..._Args, class = enable_if_t<is_invocable_v<_Op, _Bound const..., _Args...>>>
_LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Args&&... __args) const&&
noexcept(noexcept(_Op()(_VSTD::get<_Idx>(_VSTD::move(__bound_))..., _VSTD::forward<_Args>(__args)...)))
-> decltype( _Op()(_VSTD::get<_Idx>(_VSTD::move(__bound_))..., _VSTD::forward<_Args>(__args)...))
{ return _Op()(_VSTD::get<_Idx>(_VSTD::move(__bound_))..., _VSTD::forward<_Args>(__args)...); }
template <class ..._Args, class = enable_if_t<!is_invocable_v<_Op, _Bound const..., _Args...>>>
auto operator()(_Args&&...) const&& = delete;
};
// __perfect_forward implements a perfect-forwarding call wrapper as explained in [func.require].
template <class _Op, class ..._Args>
using __perfect_forward = __perfect_forward_impl<_Op, index_sequence_for<_Args...>, _Args...>;
#endif // _LIBCPP_STD_VER > 14
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP___FUNCTIONAL_PERFECT_FORWARD_H
|
