1 // -*- C++ -*- 2 //===----------------------------------------------------------------------===// 3 // 4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 5 // See https://llvm.org/LICENSE.txt for license information. 6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 7 // 8 //===----------------------------------------------------------------------===// 9 10 #ifndef _LIBCPP___ITERATOR_ITER_MOVE_H 11 #define _LIBCPP___ITERATOR_ITER_MOVE_H 12 13 #include <__concepts/class_or_enum.h> 14 #include <__config> 15 #include <__iterator/iterator_traits.h> 16 #include <__type_traits/is_reference.h> 17 #include <__type_traits/is_referenceable.h> 18 #include <__type_traits/remove_cvref.h> 19 #include <__utility/declval.h> 20 #include <__utility/forward.h> 21 #include <__utility/move.h> 22 23 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 24 # pragma GCC system_header 25 #endif 26 27 _LIBCPP_PUSH_MACROS 28 #include <__undef_macros> 29 30 _LIBCPP_BEGIN_NAMESPACE_STD 31 32 #if _LIBCPP_STD_VER >= 20 33 34 // [iterator.cust.move] 35 36 namespace ranges { 37 namespace __iter_move { 38 39 void iter_move() = delete; 40 41 template <class _Tp> requires(_Tp && __t)42concept __unqualified_iter_move = __class_or_enum<remove_cvref_t<_Tp>> && requires(_Tp&& __t) { 43 // NOLINTNEXTLINE(libcpp-robust-against-adl) iter_swap ADL calls should only be made through ranges::iter_swap 44 iter_move(std::forward<_Tp>(__t)); 45 }; 46 47 template <class _Tp> 48 concept __move_deref = !__unqualified_iter_move<_Tp> && requires(_Tp&& __t) { 49 *__t; 50 requires is_lvalue_reference_v<decltype(*__t)>; 51 }; 52 53 template <class _Tp> 54 concept __just_deref = !__unqualified_iter_move<_Tp> && !__move_deref<_Tp> && requires(_Tp&& __t) { 55 *__t; 56 requires(!is_lvalue_reference_v<decltype(*__t)>); 57 }; 58 59 // [iterator.cust.move] 60 61 struct __fn { 62 // NOLINTBEGIN(libcpp-robust-against-adl) iter_move ADL calls should only be made through ranges::iter_move 63 template <class _Ip> 64 requires __unqualified_iter_move<_Ip> decltype__fn65 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr decltype(auto) operator()(_Ip&& __i) const 66 noexcept(noexcept(iter_move(std::forward<_Ip>(__i)))) { 67 return iter_move(std::forward<_Ip>(__i)); 68 } 69 // NOLINTEND(libcpp-robust-against-adl) 70 71 template <class _Ip> 72 requires __move_deref<_Ip> 73 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Ip&& __i) const 74 noexcept(noexcept(std::move(*std::forward<_Ip>(__i)))) -> decltype(std::move(*std::forward<_Ip>(__i))) { 75 return std::move(*std::forward<_Ip>(__i)); 76 } 77 78 template <class _Ip> 79 requires __just_deref<_Ip> 80 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Ip&& __i) const 81 noexcept(noexcept(*std::forward<_Ip>(__i))) -> decltype(*std::forward<_Ip>(__i)) { 82 return *std::forward<_Ip>(__i); 83 } 84 }; 85 } // namespace __iter_move 86 87 inline namespace __cpo { 88 inline constexpr auto iter_move = __iter_move::__fn{}; 89 } // namespace __cpo 90 } // namespace ranges 91 92 template <__dereferenceable _Tp> requires(_Tp & __t)93 requires requires(_Tp& __t) { 94 { ranges::iter_move(__t) } -> __referenceable; 95 } 96 using iter_rvalue_reference_t = decltype(ranges::iter_move(std::declval<_Tp&>())); 97 98 #endif // _LIBCPP_STD_VER >= 20 99 100 _LIBCPP_END_NAMESPACE_STD 101 102 _LIBCPP_POP_MACROS 103 104 #endif // _LIBCPP___ITERATOR_ITER_MOVE_H 105