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Diffstat (limited to 'libstdc++-v3/include/bits/indirect.h')
| -rw-r--r-- | libstdc++-v3/include/bits/indirect.h | 833 |
1 files changed, 833 insertions, 0 deletions
diff --git a/libstdc++-v3/include/bits/indirect.h b/libstdc++-v3/include/bits/indirect.h new file mode 100644 index 0000000..e8000d7 --- /dev/null +++ b/libstdc++-v3/include/bits/indirect.h @@ -0,0 +1,833 @@ +// Vocabulary Types for Composite Class Design -*- C++ -*- + +// Copyright The GNU Toolchain Authors. +// +// This file is part of the GNU ISO C++ Library. This library is free +// software; you can redistribute it and/or modify it under the +// terms of the GNU General Public License as published by the +// Free Software Foundation; either version 3, or (at your option) +// any later version. + +// This library is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. + +// Under Section 7 of GPL version 3, you are granted additional +// permissions described in the GCC Runtime Library Exception, version +// 3.1, as published by the Free Software Foundation. + +// You should have received a copy of the GNU General Public License and +// a copy of the GCC Runtime Library Exception along with this program; +// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see +// <http://www.gnu.org/licenses/>. + +/** @file include/bits/indirect.h + * This is an internal header file, included by other library headers. + * Do not attempt to use it directly. @headername{memory} + */ + +#ifndef _GLIBCXX_INDIRECT_H +#define _GLIBCXX_INDIRECT_H 1 + +#pragma GCC system_header + +#include <bits/version.h> + +#if __glibcxx_indirect || __glibcxx_polymorphic // >= C++26 +#include <compare> +#include <initializer_list> +#include <bits/allocator.h> +#include <bits/alloc_traits.h> +#include <bits/allocated_ptr.h> // __allocate_guarded +#include <bits/uses_allocator.h> // allocator_arg_t +#include <bits/utility.h> // __is_in_place_type_v +#include <bits/functional_hash.h> // hash +#include <bits/memory_resource.h> // polymorphic_allocator + +namespace std _GLIBCXX_VISIBILITY(default) +{ +_GLIBCXX_BEGIN_NAMESPACE_VERSION + +#if __glibcxx_indirect + template<typename _Tp, typename _Alloc = allocator<_Tp>> + class indirect; + + template<typename _Tp> + constexpr bool __is_indirect = false; + template<typename _Tp, typename _Alloc> + constexpr bool __is_indirect<indirect<_Tp, _Alloc>> = true; + +#if _GLIBCXX_HOSTED + namespace pmr + { + template<typename _Tp> + using indirect = indirect<_Tp, polymorphic_allocator<_Tp>>; + } +#endif + + // [indirect], class template indirect + template<typename _Tp, typename _Alloc> + class indirect + { + static_assert(is_object_v<_Tp>); + static_assert(!is_array_v<_Tp>); + static_assert(!is_same_v<_Tp, in_place_t>); + static_assert(!__is_in_place_type_v<_Tp>); + static_assert(!is_const_v<_Tp> && !is_volatile_v<_Tp>); + + using _ATraits = allocator_traits<_Alloc>; + static_assert(is_same_v<_Tp, typename _ATraits::value_type>); + + public: + using value_type = _Tp; + using allocator_type = _Alloc; + using pointer = typename allocator_traits<_Alloc>::pointer; + using const_pointer = typename allocator_traits<_Alloc>::const_pointer; + + constexpr explicit + indirect() requires is_default_constructible_v<_Alloc> + : _M_objp(_M_make_obj_chk()) + { } + + constexpr explicit + indirect(allocator_arg_t, const _Alloc& __a) + : _M_alloc(__a), _M_objp(_M_make_obj_chk()) + { } + + constexpr + indirect(const indirect& __o) + : indirect(allocator_arg, + _ATraits::select_on_container_copy_construction(__o._M_alloc), + __o) + { } + + constexpr + indirect(allocator_arg_t, const _Alloc& __a, const indirect& __other) + : _M_alloc(__a) + { + if (__other._M_objp) + _M_objp = _M_make_obj_chk(__other.__get()); + else + _M_objp = nullptr; + } + + constexpr + indirect(indirect&& __other) noexcept + : _M_alloc(std::move(__other._M_alloc)), + _M_objp(std::__exchange(__other._M_objp, nullptr)) + { } + + constexpr + indirect(allocator_arg_t, const _Alloc& __a, + indirect&& __other) noexcept(_ATraits::is_always_equal::value) + : _M_alloc(__a), + _M_objp(std::__exchange(__other._M_objp, nullptr)) + { + if constexpr (!_ATraits::is_always_equal::value) + if (_M_objp && _M_alloc != __other._M_alloc) + { + static_assert(sizeof(_Tp) != 0, "must be a complete type"); + + // _M_alloc cannot free _M_objp, give it back to __other. + __other._M_objp = std::__exchange(_M_objp, nullptr); + // And create a new object that can be freed by _M_alloc. + _M_objp = _M_make_obj(std::move(*__other._M_objp)); + } + } + + template<typename _Up = _Tp> + requires (!is_same_v<remove_cvref_t<_Up>, in_place_t>) + && (!is_same_v<remove_cvref_t<_Up>, indirect>) + && is_constructible_v<_Tp, _Up> + && is_default_constructible_v<_Alloc> + constexpr explicit + indirect(_Up&& __u) + : _M_objp(_M_make_obj(std::forward<_Up>(__u))) + { } + + template<typename _Up = _Tp> + requires (!is_same_v<remove_cvref_t<_Up>, in_place_t>) + && (!is_same_v<remove_cvref_t<_Up>, indirect>) + && is_constructible_v<_Tp, _Up> + constexpr explicit + indirect(allocator_arg_t, const _Alloc& __a, _Up&& __u) + : _M_alloc(__a), _M_objp(_M_make_obj(std::forward<_Up>(__u))) + { } + + template<typename... _Us> + requires is_constructible_v<_Tp, _Us...> + && is_default_constructible_v<_Alloc> + constexpr explicit + indirect(in_place_t, _Us&&... __us) + : _M_objp(_M_make_obj(std::forward<_Us>(__us)...)) + { } + + template<typename... _Us> + requires is_constructible_v<_Tp, _Us...> + constexpr explicit + indirect(allocator_arg_t, const _Alloc& __a, in_place_t, _Us&&... __us) + : _M_alloc(__a), + _M_objp(_M_make_obj(std::forward<_Us>(__us)...)) + { } + + template<typename _Ip, typename... _Us> + requires is_constructible_v<_Tp, initializer_list<_Ip>&, _Us...> + && is_default_constructible_v<_Alloc> + constexpr explicit + indirect(in_place_t, initializer_list<_Ip> __il, _Us&&... __us) + : _M_objp(_M_make_obj(__il, std::forward<_Us>(__us)...)) + { } + + template<typename _Ip, typename... _Us> + requires is_constructible_v<_Tp, initializer_list<_Ip>&, _Us...> + constexpr explicit + indirect(allocator_arg_t, const _Alloc& __a, + in_place_t, initializer_list<_Ip> __il, _Us&&... __us) + : _M_alloc(__a), + _M_objp(_M_make_obj(__il, std::forward<_Us>(__us)...)) + { } + + constexpr ~indirect() + { + static_assert(sizeof(_Tp) != 0, "must be a complete type"); + _M_reset(nullptr); + } + + constexpr indirect& + operator=(const indirect& __other) + { + static_assert(is_copy_assignable_v<_Tp>); + static_assert(is_copy_constructible_v<_Tp>); + + if (__builtin_addressof(__other) == this) [[unlikely]] + return *this; + + constexpr bool __pocca + = _ATraits::propagate_on_container_copy_assignment::value; + + pointer __ptr = nullptr; + if (__other._M_objp) + { + if (_ATraits::is_always_equal::value + || _M_alloc == __other._M_alloc) + { + if (_M_objp) + { + *_M_objp = __other.__get(); + if constexpr (__pocca) + _M_alloc = __other._M_alloc; + return *this; + } + } + const indirect& __x = __pocca ? __other : *this; + __ptr = __x._M_make_obj(__other.__get()); + } + + _M_reset(__ptr); + + if constexpr (__pocca) + _M_alloc = __other._M_alloc; + + return *this; + } + + constexpr indirect& + operator=(indirect&& __other) + noexcept(_ATraits::propagate_on_container_move_assignment::value + || _ATraits::is_always_equal::value) + { + // N5008 says is_copy_constructible_v<T> here, but that seems wrong. + // We only require move-constructible, and only for unequal allocators. + + if (__builtin_addressof(__other) == this) [[unlikely]] + return *this; + + constexpr bool __pocma + = _ATraits::propagate_on_container_move_assignment::value; + + pointer __ptr = nullptr; + + // _GLIBCXX_RESOLVE_LIB_DEFECTS + // 4251. Move assignment for indirect unnecessarily requires copy construction + if constexpr (_ATraits::is_always_equal::value || __pocma) + __ptr = std::__exchange(__other._M_objp, nullptr); + else if (_M_alloc == __other._M_alloc) + __ptr = std::__exchange(__other._M_objp, nullptr); + else if (__other._M_objp) + { + static_assert(is_move_constructible_v<_Tp>); + __ptr = _M_make_obj(std::move(*__other._M_objp)); + } + + _M_reset(__ptr); + + if constexpr (__pocma) + _M_alloc = __other._M_alloc; + + return *this; + } + + template<typename _Up = _Tp> + requires (!is_same_v<remove_cvref_t<_Up>, indirect>) + && is_constructible_v<_Tp, _Up> && is_assignable_v<_Tp&, _Up> + constexpr indirect& + operator=(_Up&& __u) + { + if (_M_objp == nullptr) + _M_objp = _M_make_obj(std::forward<_Up>(__u)); + else + *_M_objp = std::forward<_Up>(__u); + + return *this; + } + + template<typename _Self> + constexpr auto&& + operator*(this _Self&& __self) noexcept + { + __glibcxx_assert(__self._M_objp != nullptr); + return std::forward_like<_Self>(*((_Self)__self)._M_objp); + } + + constexpr const_pointer + operator->() const noexcept + { + // Do we want to enforce this? __glibcxx_assert(_M_objp != nullptr); + return _M_objp; + } + + constexpr pointer + operator->() noexcept + { + // Do we want to enforce this? __glibcxx_assert(_M_objp != nullptr); + return _M_objp; + } + + constexpr bool + valueless_after_move() const noexcept { return _M_objp == nullptr; } + + constexpr allocator_type + get_allocator() const noexcept { return _M_alloc; } + + constexpr void + swap(indirect& __other) + noexcept(_ATraits::propagate_on_container_swap::value + || _ATraits::is_always_equal::value) + { + using std::swap; + swap(_M_objp, __other._M_objp); + if constexpr (_ATraits::propagate_on_container_swap::value) + swap(_M_alloc, __other._M_alloc); + else if constexpr (!_ATraits::is_always_equal::value) + __glibcxx_assert(_M_alloc == __other._M_alloc); + } + + friend constexpr void + swap(indirect& __lhs, indirect& __rhs) + noexcept(_ATraits::propagate_on_container_swap::value + || _ATraits::is_always_equal::value) + { __lhs.swap(__rhs); } + + template<typename _Up, typename _Alloc2> + requires requires (const _Tp& __t, const _Up& __u) { __t == __u; } + friend constexpr bool + operator==(const indirect& __lhs, const indirect<_Up, _Alloc2>& __rhs) + noexcept(noexcept(*__lhs == *__rhs)) + { + if (!__lhs._M_objp || !__rhs._M_objp) + return bool(__lhs._M_objp) == bool(__rhs._M_objp); + else + return __lhs.__get() == __rhs.__get(); + } + + template<typename _Up> + requires (!__is_indirect<_Up>) // See PR c++/99599 + && requires (const _Tp& __t, const _Up& __u) { __t == __u; } + friend constexpr bool + operator==(const indirect& __lhs, const _Up& __rhs) + noexcept(noexcept(*__lhs == __rhs)) + { + if (!__lhs._M_objp) + return false; + else + return __lhs.__get() == __rhs; + } + + template<typename _Up, typename _Alloc2> + friend constexpr __detail::__synth3way_t<_Tp, _Up> + operator<=>(const indirect& __lhs, const indirect<_Up, _Alloc2>& __rhs) + noexcept(noexcept(__detail::__synth3way(*__lhs, *__rhs))) + { + if (!__lhs._M_objp || !__rhs._M_objp) + return bool(__lhs._M_objp) <=> bool(__rhs._M_objp); + else + return __detail::__synth3way(__lhs.__get(), __rhs.__get()); + } + + template<typename _Up> + requires (!__is_indirect<_Up>) // See PR c++/99599 + friend constexpr __detail::__synth3way_t<_Tp, _Up> + operator<=>(const indirect& __lhs, const _Up& __rhs) + noexcept(noexcept(__detail::__synth3way(*__lhs, __rhs))) + { + if (!__lhs._M_objp) + return strong_ordering::less; + else + return __detail::__synth3way(__lhs.__get(), __rhs); + } + + private: + template<typename, typename> friend class indirect; + + constexpr void + _M_reset(pointer __ptr) noexcept + { + if (_M_objp) + { + _ATraits::destroy(_M_alloc, std::to_address(_M_objp)); + _ATraits::deallocate(_M_alloc, _M_objp, 1); + } + _M_objp = __ptr; + } + + template<typename... _Args> + constexpr pointer + _M_make_obj(_Args&&... __args) const + { + _Scoped_allocation __sa(_M_alloc, in_place, + std::forward<_Args>(__args)...); + return __sa.release(); + } + + // Enforces is_constructible check and then calls _M_make_obj. + template<typename... _Args> + [[__gnu__::__always_inline__]] + constexpr pointer + _M_make_obj_chk(_Args&&... __args) const + { + static_assert(is_constructible_v<_Tp, _Args...>); + return _M_make_obj(std::forward<_Args>(__args)...); + } + + // Always-const accessor that avoids ADL for operator*. + // This can be preferable to using *_M_objp because that might give _Tp&. + // This can be preferable to using **this because that does ADL. + [[__gnu__::__always_inline__]] + constexpr const _Tp& + __get() const noexcept + { return *_M_objp; } + + [[no_unique_address]] _Alloc _M_alloc = _Alloc(); + pointer _M_objp; // Pointer to the owned object. + }; + + template<typename _Value> + indirect(_Value) -> indirect<_Value>; + + template<typename _Alloc, typename _Value> + indirect(allocator_arg_t, _Alloc, _Value) + -> indirect<_Value, __alloc_rebind<_Alloc, _Value>>; + + // [indirect.hash], hash support + template<typename _Tp, typename _Alloc> + requires is_default_constructible_v<hash<_Tp>> + struct hash<indirect<_Tp, _Alloc>> + { + constexpr size_t + operator()(const indirect<_Tp, _Alloc>& __t) const + noexcept(noexcept(hash<_Tp>{}(*__t))) + { + // We pick an arbitrary hash for valueless indirect objects + // which hopefully usual values of _Tp won't typically hash to. + if (__t.valueless_after_move()) + return -4444zu; + return hash<_Tp>{}(*__t); + } + }; + + template<typename _Tp, typename _Alloc> + struct __is_fast_hash<hash<indirect<_Tp, _Alloc>>> + : __is_fast_hash<hash<_Tp>> + { }; +#endif // __glibcxx_indirect + +#if __glibcxx_polymorphic // C++26 && HOSTED + template<typename _Tp, typename _Alloc = allocator<_Tp>> + class polymorphic; + + namespace pmr + { + template<typename _Tp> + using polymorphic = polymorphic<_Tp, polymorphic_allocator<_Tp>>; + } + + // [polymorphic], class template polymorphic + template<typename _Tp, typename _Alloc> + class polymorphic + { + static_assert(is_object_v<_Tp>); + static_assert(!is_array_v<_Tp>); + static_assert(!is_same_v<_Tp, in_place_t>); + static_assert(!__is_in_place_type_v<_Tp>); + static_assert(!is_const_v<_Tp> && !is_volatile_v<_Tp>); + + using _ATraits = allocator_traits<_Alloc>; + static_assert(is_same_v<_Tp, typename _ATraits::value_type>); + + // The owned object is embedded within a control block which knows the + // dynamic type and manages cloning and destroying the owned object. + struct _Obj + { + typename _ATraits::pointer _M_objp{}; // pointer to the owned object. + + // A pointer to this type, e.g. _Obj* + using pointer + = typename _ATraits::template rebind_traits<_Obj>::pointer; + + enum class _Op { _Dispose = 1, _Copy = 2, _Move = 3 }; + + constexpr virtual pointer + _M_manage(const _Alloc&, _Op, void* = nullptr) = 0; + }; + + template<typename _Up> + struct _Obj_impl : _Obj + { + using _MyTraits + = typename _ATraits::template rebind_traits<_Obj_impl>; + + using _Op = _Obj::_Op; + + union _Uninitialized { + constexpr _Uninitialized() { } + constexpr ~_Uninitialized() { } + _Up _M_objp; + }; + _Uninitialized _M_u; + + template<typename... _Args> + constexpr + _Obj_impl(typename _MyTraits::allocator_type& __a, + _Args&&... __args) + { + using _PtrTr = pointer_traits<typename _ATraits::pointer>; + _MyTraits::construct(__a, __builtin_addressof(_M_u._M_objp), + std::forward<_Args>(__args)...); + this->_M_objp = _PtrTr::pointer_to(_M_u._M_objp); + } + + constexpr virtual typename _Obj::pointer + _M_manage(const _Alloc& __a, _Op __op, void*) override + { + + switch (__op) + { + case _Op::_Move: + return _S_make_obj<_Up>(__a, std::move(_M_u._M_objp)); + case _Op::_Copy: + return _S_make_obj<_Up>(__a, + const_cast<const _Up&>(_M_u._M_objp)); + case _Op::_Dispose: + { + using _PtrTr = pointer_traits<typename _MyTraits::pointer>; + typename _MyTraits::allocator_type __a2(__a); + _MyTraits::destroy(__a2, std::__addressof(_M_u._M_objp)); + _MyTraits::deallocate(__a2, _PtrTr::pointer_to(*this), 1); + return nullptr; + } + } + __builtin_unreachable(); + } + }; + + // TODO: the standard permits a small-object optimization where the + // owned object is nested within the std::polymorphic not on the heap. + + public: + + using value_type = _Tp; + using allocator_type = _Alloc; + using pointer = typename allocator_traits<_Alloc>::pointer; + using const_pointer = typename allocator_traits<_Alloc>::const_pointer; + + constexpr explicit + polymorphic() requires is_default_constructible_v<_Alloc> + : polymorphic(in_place_type<_Tp>) + { } + + constexpr explicit + polymorphic(allocator_arg_t, const _Alloc& __a) + : polymorphic(allocator_arg, __a, in_place_type<_Tp>) + { } + + constexpr + polymorphic(const polymorphic& __other) + : polymorphic(allocator_arg, + _ATraits::select_on_container_copy_construction( + __other._M_alloc), + __other) + { } + + constexpr + polymorphic(allocator_arg_t, const _Alloc& __a, + const polymorphic& __other) + : _M_alloc(__a) + { + if (__other._M_objp) + _M_objp = __other._M_objp->_M_manage(__a, _Obj::_Op::_Copy); + else + _M_objp = nullptr; + } + + constexpr + polymorphic(polymorphic&& __other) noexcept + : _M_alloc(std::move(__other._M_alloc)), + _M_objp(std::__exchange(__other._M_objp, nullptr)) + { } + + constexpr + polymorphic(allocator_arg_t, const _Alloc& __a, polymorphic&& __other) + noexcept(_ATraits::is_always_equal::value) + : _M_alloc(__a), + _M_objp(std::__exchange(__other._M_objp, nullptr)) + { + if constexpr (!_ATraits::is_always_equal::value) + if (_M_objp && _M_alloc != __other._M_alloc) + { + // _M_alloc cannot free _M_objp, give it back to __other. + __other._M_objp = std::__exchange(_M_objp, nullptr); + // And create a new object that can be freed by _M_alloc. + _M_objp = __other._M_objp->_M_manage(__a, _Obj::_Op::_Move); + } + } + + template<typename _Up = _Tp, typename _UUp = remove_cvref_t<_Up>> + requires (!is_same_v<_UUp, polymorphic>) + && (!__is_in_place_type_v<_UUp>) + && derived_from<_UUp, _Tp> + && is_constructible_v<_UUp, _Up> + && is_copy_constructible_v<_UUp> + && is_default_constructible_v<_Alloc> + constexpr explicit + polymorphic(_Up&& __u) + : _M_objp(_M_make_obj<_UUp>(std::forward<_Up>(__u))) + { } + + template<typename _Up = _Tp, typename _UUp = remove_cvref_t<_Up>> + requires (!is_same_v<_UUp, polymorphic>) + && (!__is_in_place_type_v<_UUp>) + && derived_from<_UUp, _Tp> + && is_constructible_v<_UUp, _Up> + && is_copy_constructible_v<_UUp> + constexpr explicit + polymorphic(allocator_arg_t, const _Alloc& __a, _Up&& __u) + : _M_alloc(__a), _M_objp(_M_make_obj<_UUp>(std::forward<_Up>(__u))) + { } + + template<typename _Up, typename... _Ts> + requires is_same_v<remove_cvref_t<_Up>, _Up> + && derived_from<_Up, _Tp> + && is_constructible_v<_Up, _Ts...> + && is_copy_constructible_v<_Up> + && is_default_constructible_v<_Alloc> + constexpr explicit + polymorphic(in_place_type_t<_Up> __t, _Ts&&... __ts) + : _M_objp(_M_make_obj<_Up>(std::forward<_Ts>(__ts)...)) + { } + + template<typename _Up, typename... _Ts> + requires is_same_v<remove_cvref_t<_Up>, _Up> + && derived_from<_Up, _Tp> + && is_constructible_v<_Up, _Ts...> + && is_copy_constructible_v<_Up> + constexpr explicit + polymorphic(allocator_arg_t, const _Alloc& __a, + in_place_type_t<_Up>, _Ts&&... __ts) + : _M_alloc(__a), + _M_objp(_M_make_obj<_Up>(std::forward<_Ts>(__ts)...)) + { } + + template<typename _Up, typename _Ip, typename... _Us> + requires is_same_v<remove_cvref_t<_Up>, _Up> + && derived_from<_Up, _Tp> + && is_constructible_v<_Up, initializer_list<_Ip>&, _Us...> + && is_copy_constructible_v<_Up> + && is_default_constructible_v<_Alloc> + constexpr explicit + polymorphic(in_place_type_t<_Up>, initializer_list<_Ip> __il, + _Us&&... __us) + : _M_objp(_M_make_obj<_Up>(__il, std::forward<_Us>(__us)...)) + { } + + template<typename _Up, typename _Ip, typename... _Us> + requires is_same_v<remove_cvref_t<_Up>, _Up> + && derived_from<_Up, _Tp> + && is_constructible_v<_Up, initializer_list<_Ip>&, _Us...> + && is_copy_constructible_v<_Up> + constexpr explicit + polymorphic(allocator_arg_t, const _Alloc& __a, + in_place_type_t<_Up>, initializer_list<_Ip> __il, + _Us&&... __us) + : _M_alloc(__a), + _M_objp(_M_make_obj<_Up>(__il, std::forward<_Us>(__us)...)) + { } + + constexpr ~polymorphic() + { + static_assert(sizeof(_Tp) != 0, "must be a complete type"); + _M_reset(nullptr); + } + + constexpr polymorphic& + operator=(const polymorphic& __other) + { + static_assert(sizeof(_Tp) != 0, "must be a complete type"); + + if (__builtin_addressof(__other) == this) [[unlikely]] + return *this; + + constexpr bool __pocca + = _ATraits::propagate_on_container_copy_assignment::value; + + typename _Obj::pointer __ptr = nullptr; + if (__other._M_objp) + { + auto& __a = __pocca ? __other._M_alloc : _M_alloc; + __ptr = __other._M_objp->_M_manage(__a, _Obj::_Op::_Copy); + } + + _M_reset(__ptr); + + if constexpr (__pocca) + _M_alloc = __other._M_alloc; + + return *this; + } + + constexpr polymorphic& + operator=(polymorphic&& __other) + noexcept(_ATraits::propagate_on_container_move_assignment::value + || _ATraits::is_always_equal::value) + { + if (__builtin_addressof(__other) == this) [[unlikely]] + return *this; + + constexpr bool __pocma + = _ATraits::propagate_on_container_move_assignment::value; + + typename _Obj::pointer __ptr = nullptr; + + // _GLIBCXX_RESOLVE_LIB_DEFECTS + // 4251. Move assignment for indirect unnecessarily requires copy construction + if constexpr (_ATraits::is_always_equal::value || __pocma) + __ptr = std::__exchange(__other._M_objp, nullptr); + else if (_M_alloc == __other._M_alloc) + __ptr = std::__exchange(__other._M_objp, nullptr); + else if (__other._M_objp) + { + static_assert(sizeof(_Tp) != 0, "must be a complete type"); + __ptr = __other._M_objp->_M_manage(_M_alloc, _Obj::_Op::_Move); + } + + _M_reset(__ptr); + + if constexpr (__pocma) + _M_alloc = __other._M_alloc; + + return *this; + } + + constexpr const _Tp& + operator*() const noexcept + { + __glibcxx_assert(_M_objp != nullptr); + return *_M_objp->_M_objp; + } + + constexpr _Tp& + operator*() noexcept + { + __glibcxx_assert(_M_objp != nullptr); + return *_M_objp->_M_objp; + } + + constexpr const_pointer + operator->() const noexcept + { + __glibcxx_assert(_M_objp != nullptr); + return _M_objp ? _M_objp->_M_objp : const_pointer{}; + } + + constexpr pointer + operator->() noexcept + { + __glibcxx_assert(_M_objp != nullptr); + return _M_objp ? _M_objp->_M_objp : pointer{}; + } + + constexpr bool + valueless_after_move() const noexcept { return _M_objp == nullptr; } + + constexpr allocator_type + get_allocator() const noexcept { return _M_alloc; } + + constexpr void + swap(polymorphic& __other) + noexcept(_ATraits::propagate_on_container_swap::value + || _ATraits::is_always_equal::value) + { + using std::swap; + swap(_M_objp, __other._M_objp); + if constexpr (_ATraits::propagate_on_container_swap::value) + swap(_M_alloc, __other._M_alloc); + else if constexpr (!_ATraits::is_always_equal::value) + __glibcxx_assert(_M_alloc == __other._M_alloc); + } + + friend constexpr void + swap(polymorphic& __lhs, polymorphic& __rhs) + noexcept(_ATraits::propagate_on_container_swap::value + || _ATraits::is_always_equal::value) + { __lhs.swap(__rhs); } + + private: + template<typename _Up, typename... _Args> + static constexpr typename _Obj::pointer + _S_make_obj(const _Alloc& __a, _Args&&... __args) + { + __alloc_rebind<_Alloc, _Obj_impl<_Up>> __objalloc(__a); + _Scoped_allocation __sa(__objalloc, in_place, __objalloc, + std::forward<_Args>(__args)...); + auto __obj = __sa.release(); + // FIXME: We need to downcast from _Obj_impl<U>* to _Obj* but the + // the pointer_traits usage breaks in constexpr. PR c++/110714 + if constexpr (is_pointer_v<typename _Obj::pointer>) + return __obj; + else + return pointer_traits<typename _Obj::pointer>::pointer_to(*__obj); + } + + template<typename _Up, typename... _Args> + constexpr typename _Obj::pointer + _M_make_obj(_Args&&... __args) const + { return _S_make_obj<_Up>(_M_alloc, std::forward<_Args>(__args)...); } + + constexpr void + _M_reset(typename _Obj::pointer __ptr) noexcept + { + if (_M_objp) + _M_objp->_M_manage(_M_alloc, _Obj::_Op::_Dispose); + _M_objp = __ptr; + } + + [[no_unique_address]] _Alloc _M_alloc = _Alloc(); + typename _Obj::pointer _M_objp; + }; +#endif // __glibcxx_polymorphic + +_GLIBCXX_END_NAMESPACE_VERSION +} // namespace +#endif // C++26 __glibcxx_indirect || __glibcxx_polymorphic + +#endif // _GLIBCXX_INDIRECT_H |