| // -*- 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 <__type_traits/enable_if.h> |
| #include <__type_traits/invoke.h> |
| #include <__type_traits/is_constructible.h> |
| #include <__utility/declval.h> |
| #include <__utility/forward.h> |
| #include <__utility/integer_sequence.h> |
| #include <__utility/move.h> |
| #include <tuple> |
| |
| #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) |
| # pragma GCC system_header |
| #endif |
| |
| _LIBCPP_PUSH_MACROS |
| #include <__undef_macros> |
| |
| _LIBCPP_BEGIN_NAMESPACE_STD |
| |
| #if _LIBCPP_STD_VER >= 17 |
| |
| template <class _Op, class _Indices, class... _BoundArgs> |
| struct __perfect_forward_impl; |
| |
| template <class _Op, size_t... _Idx, class... _BoundArgs> |
| struct __perfect_forward_impl<_Op, index_sequence<_Idx...>, _BoundArgs...> { |
| private: |
| tuple<_BoundArgs...> __bound_args_; |
| |
| public: |
| template <class... _Args, class = enable_if_t< |
| is_constructible_v<tuple<_BoundArgs...>, _Args&&...> |
| >> |
| _LIBCPP_HIDE_FROM_ABI explicit constexpr __perfect_forward_impl(_Args&&... __bound_args) |
| : __bound_args_(_VSTD::forward<_Args>(__bound_args)...) {} |
| |
| _LIBCPP_HIDE_FROM_ABI __perfect_forward_impl(__perfect_forward_impl const&) = default; |
| _LIBCPP_HIDE_FROM_ABI __perfect_forward_impl(__perfect_forward_impl&&) = default; |
| |
| _LIBCPP_HIDE_FROM_ABI __perfect_forward_impl& operator=(__perfect_forward_impl const&) = default; |
| _LIBCPP_HIDE_FROM_ABI __perfect_forward_impl& operator=(__perfect_forward_impl&&) = default; |
| |
| template <class... _Args, class = enable_if_t<is_invocable_v<_Op, _BoundArgs&..., _Args...>>> |
| _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Args&&... __args) & |
| noexcept(noexcept(_Op()(_VSTD::get<_Idx>(__bound_args_)..., _VSTD::forward<_Args>(__args)...))) |
| -> decltype( _Op()(_VSTD::get<_Idx>(__bound_args_)..., _VSTD::forward<_Args>(__args)...)) |
| { return _Op()(_VSTD::get<_Idx>(__bound_args_)..., _VSTD::forward<_Args>(__args)...); } |
| |
| template <class... _Args, class = enable_if_t<!is_invocable_v<_Op, _BoundArgs&..., _Args...>>> |
| auto operator()(_Args&&...) & = delete; |
| |
| template <class... _Args, class = enable_if_t<is_invocable_v<_Op, _BoundArgs const&..., _Args...>>> |
| _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Args&&... __args) const& |
| noexcept(noexcept(_Op()(_VSTD::get<_Idx>(__bound_args_)..., _VSTD::forward<_Args>(__args)...))) |
| -> decltype( _Op()(_VSTD::get<_Idx>(__bound_args_)..., _VSTD::forward<_Args>(__args)...)) |
| { return _Op()(_VSTD::get<_Idx>(__bound_args_)..., _VSTD::forward<_Args>(__args)...); } |
| |
| template <class... _Args, class = enable_if_t<!is_invocable_v<_Op, _BoundArgs const&..., _Args...>>> |
| auto operator()(_Args&&...) const& = delete; |
| |
| template <class... _Args, class = enable_if_t<is_invocable_v<_Op, _BoundArgs..., _Args...>>> |
| _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Args&&... __args) && |
| noexcept(noexcept(_Op()(_VSTD::get<_Idx>(_VSTD::move(__bound_args_))..., _VSTD::forward<_Args>(__args)...))) |
| -> decltype( _Op()(_VSTD::get<_Idx>(_VSTD::move(__bound_args_))..., _VSTD::forward<_Args>(__args)...)) |
| { return _Op()(_VSTD::get<_Idx>(_VSTD::move(__bound_args_))..., _VSTD::forward<_Args>(__args)...); } |
| |
| template <class... _Args, class = enable_if_t<!is_invocable_v<_Op, _BoundArgs..., _Args...>>> |
| auto operator()(_Args&&...) && = delete; |
| |
| template <class... _Args, class = enable_if_t<is_invocable_v<_Op, _BoundArgs const..., _Args...>>> |
| _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Args&&... __args) const&& |
| noexcept(noexcept(_Op()(_VSTD::get<_Idx>(_VSTD::move(__bound_args_))..., _VSTD::forward<_Args>(__args)...))) |
| -> decltype( _Op()(_VSTD::get<_Idx>(_VSTD::move(__bound_args_))..., _VSTD::forward<_Args>(__args)...)) |
| { return _Op()(_VSTD::get<_Idx>(_VSTD::move(__bound_args_))..., _VSTD::forward<_Args>(__args)...); } |
| |
| template <class... _Args, class = enable_if_t<!is_invocable_v<_Op, _BoundArgs 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 >= 17 |
| |
| _LIBCPP_END_NAMESPACE_STD |
| |
| _LIBCPP_POP_MACROS |
| |
| #endif // _LIBCPP___FUNCTIONAL_PERFECT_FORWARD_H |