1fe6060f1SDimitry Andric // -*- C++ -*- 2fe6060f1SDimitry Andric //===----------------------------------------------------------------------===// 3fe6060f1SDimitry Andric // 4fe6060f1SDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 5fe6060f1SDimitry Andric // See https://llvm.org/LICENSE.txt for license information. 6fe6060f1SDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 7fe6060f1SDimitry Andric // 8fe6060f1SDimitry Andric //===----------------------------------------------------------------------===// 9fe6060f1SDimitry Andric 10fe6060f1SDimitry Andric #ifndef _LIBCPP___FUNCTIONAL_PERFECT_FORWARD_H 11fe6060f1SDimitry Andric #define _LIBCPP___FUNCTIONAL_PERFECT_FORWARD_H 12fe6060f1SDimitry Andric 13fe6060f1SDimitry Andric #include <__config> 1406c3fb27SDimitry Andric #include <__type_traits/enable_if.h> 1506c3fb27SDimitry Andric #include <__type_traits/invoke.h> 1606c3fb27SDimitry Andric #include <__type_traits/is_constructible.h> 17349cc55cSDimitry Andric #include <__utility/declval.h> 18349cc55cSDimitry Andric #include <__utility/forward.h> 1906c3fb27SDimitry Andric #include <__utility/integer_sequence.h> 20349cc55cSDimitry Andric #include <__utility/move.h> 21fe6060f1SDimitry Andric #include <tuple> 22fe6060f1SDimitry Andric 23fe6060f1SDimitry Andric #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 24fe6060f1SDimitry Andric # pragma GCC system_header 25fe6060f1SDimitry Andric #endif 26fe6060f1SDimitry Andric 2706c3fb27SDimitry Andric _LIBCPP_PUSH_MACROS 2806c3fb27SDimitry Andric #include <__undef_macros> 2906c3fb27SDimitry Andric 30fe6060f1SDimitry Andric _LIBCPP_BEGIN_NAMESPACE_STD 31fe6060f1SDimitry Andric 3206c3fb27SDimitry Andric #if _LIBCPP_STD_VER >= 17 33fe6060f1SDimitry Andric 3481ad6265SDimitry Andric template <class _Op, class _Indices, class... _BoundArgs> 35fe6060f1SDimitry Andric struct __perfect_forward_impl; 36fe6060f1SDimitry Andric 3781ad6265SDimitry Andric template <class _Op, size_t... _Idx, class... _BoundArgs> 3881ad6265SDimitry Andric struct __perfect_forward_impl<_Op, index_sequence<_Idx...>, _BoundArgs...> { 39349cc55cSDimitry Andric private: 4081ad6265SDimitry Andric tuple<_BoundArgs...> __bound_args_; 41fe6060f1SDimitry Andric 42349cc55cSDimitry Andric public: 43*cb14a3feSDimitry Andric template <class... _Args, class = enable_if_t< is_constructible_v<tuple<_BoundArgs...>, _Args&&...> >> 4406c3fb27SDimitry Andric _LIBCPP_HIDE_FROM_ABI explicit constexpr __perfect_forward_impl(_Args&&... __bound_args) 455f757f3fSDimitry Andric : __bound_args_(std::forward<_Args>(__bound_args)...) {} 46fe6060f1SDimitry Andric 4706c3fb27SDimitry Andric _LIBCPP_HIDE_FROM_ABI __perfect_forward_impl(__perfect_forward_impl const&) = default; 4806c3fb27SDimitry Andric _LIBCPP_HIDE_FROM_ABI __perfect_forward_impl(__perfect_forward_impl&&) = default; 49fe6060f1SDimitry Andric 5006c3fb27SDimitry Andric _LIBCPP_HIDE_FROM_ABI __perfect_forward_impl& operator=(__perfect_forward_impl const&) = default; 5106c3fb27SDimitry Andric _LIBCPP_HIDE_FROM_ABI __perfect_forward_impl& operator=(__perfect_forward_impl&&) = default; 52fe6060f1SDimitry Andric 5381ad6265SDimitry Andric template <class... _Args, class = enable_if_t<is_invocable_v<_Op, _BoundArgs&..., _Args...>>> 54*cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Args&&... __args) & noexcept( 55*cb14a3feSDimitry Andric noexcept(_Op()(std::get<_Idx>(__bound_args_)..., std::forward<_Args>(__args)...))) 56*cb14a3feSDimitry Andric -> decltype(_Op()(std::get<_Idx>(__bound_args_)..., std::forward<_Args>(__args)...)) { 57*cb14a3feSDimitry Andric return _Op()(std::get<_Idx>(__bound_args_)..., std::forward<_Args>(__args)...); 58*cb14a3feSDimitry Andric } 59fe6060f1SDimitry Andric 6081ad6265SDimitry Andric template <class... _Args, class = enable_if_t<!is_invocable_v<_Op, _BoundArgs&..., _Args...>>> 61349cc55cSDimitry Andric auto operator()(_Args&&...) & = delete; 62fe6060f1SDimitry Andric 6381ad6265SDimitry Andric template <class... _Args, class = enable_if_t<is_invocable_v<_Op, _BoundArgs const&..., _Args...>>> 64*cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Args&&... __args) const& noexcept( 65*cb14a3feSDimitry Andric noexcept(_Op()(std::get<_Idx>(__bound_args_)..., std::forward<_Args>(__args)...))) 66*cb14a3feSDimitry Andric -> decltype(_Op()(std::get<_Idx>(__bound_args_)..., std::forward<_Args>(__args)...)) { 67*cb14a3feSDimitry Andric return _Op()(std::get<_Idx>(__bound_args_)..., std::forward<_Args>(__args)...); 68*cb14a3feSDimitry Andric } 69fe6060f1SDimitry Andric 7081ad6265SDimitry Andric template <class... _Args, class = enable_if_t<!is_invocable_v<_Op, _BoundArgs const&..., _Args...>>> 71349cc55cSDimitry Andric auto operator()(_Args&&...) const& = delete; 72349cc55cSDimitry Andric 7381ad6265SDimitry Andric template <class... _Args, class = enable_if_t<is_invocable_v<_Op, _BoundArgs..., _Args...>>> 74*cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Args&&... __args) && noexcept( 75*cb14a3feSDimitry Andric noexcept(_Op()(std::get<_Idx>(std::move(__bound_args_))..., std::forward<_Args>(__args)...))) 76*cb14a3feSDimitry Andric -> decltype(_Op()(std::get<_Idx>(std::move(__bound_args_))..., std::forward<_Args>(__args)...)) { 77*cb14a3feSDimitry Andric return _Op()(std::get<_Idx>(std::move(__bound_args_))..., std::forward<_Args>(__args)...); 78*cb14a3feSDimitry Andric } 79349cc55cSDimitry Andric 8081ad6265SDimitry Andric template <class... _Args, class = enable_if_t<!is_invocable_v<_Op, _BoundArgs..., _Args...>>> 81349cc55cSDimitry Andric auto operator()(_Args&&...) && = delete; 82349cc55cSDimitry Andric 8381ad6265SDimitry Andric template <class... _Args, class = enable_if_t<is_invocable_v<_Op, _BoundArgs const..., _Args...>>> 84*cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Args&&... __args) const&& noexcept( 85*cb14a3feSDimitry Andric noexcept(_Op()(std::get<_Idx>(std::move(__bound_args_))..., std::forward<_Args>(__args)...))) 86*cb14a3feSDimitry Andric -> decltype(_Op()(std::get<_Idx>(std::move(__bound_args_))..., std::forward<_Args>(__args)...)) { 87*cb14a3feSDimitry Andric return _Op()(std::get<_Idx>(std::move(__bound_args_))..., std::forward<_Args>(__args)...); 88*cb14a3feSDimitry Andric } 89349cc55cSDimitry Andric 9081ad6265SDimitry Andric template <class... _Args, class = enable_if_t<!is_invocable_v<_Op, _BoundArgs const..., _Args...>>> 91349cc55cSDimitry Andric auto operator()(_Args&&...) const&& = delete; 92fe6060f1SDimitry Andric }; 93fe6060f1SDimitry Andric 94349cc55cSDimitry Andric // __perfect_forward implements a perfect-forwarding call wrapper as explained in [func.require]. 95fe6060f1SDimitry Andric template <class _Op, class... _Args> 96349cc55cSDimitry Andric using __perfect_forward = __perfect_forward_impl<_Op, index_sequence_for<_Args...>, _Args...>; 97fe6060f1SDimitry Andric 9806c3fb27SDimitry Andric #endif // _LIBCPP_STD_VER >= 17 99fe6060f1SDimitry Andric 100fe6060f1SDimitry Andric _LIBCPP_END_NAMESPACE_STD 101fe6060f1SDimitry Andric 10206c3fb27SDimitry Andric _LIBCPP_POP_MACROS 10306c3fb27SDimitry Andric 104fe6060f1SDimitry Andric #endif // _LIBCPP___FUNCTIONAL_PERFECT_FORWARD_H 105