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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-exception7//8//===----------------------------------------------------------------------===//9 10#ifndef _LIBCPP_EXPERIMENTAL_MEMORY11#define _LIBCPP_EXPERIMENTAL_MEMORY12 13/*14 experimental/memory synopsis15 16namespace std::experimental::inline fundamentals_v2 {17 18template <class W> class observer_ptr {19public:20 using element_type = W;21 using pointer = add_pointer_t<W>; // exposition-only22 using reference = add_lvalue_reference_t<W>; // exposition-only23 24 // default ctor25 constexpr observer_ptr() noexcept;26 27 // pointer-accepting ctors28 constexpr observer_ptr(nullptr_t) noexcept;29 constexpr explicit observer_ptr(pointer) noexcept;30 31 // copying ctors (in addition to compiler-generated copy ctor)32 template <class W2> constexpr observer_ptr(observer_ptr<W2>) noexcept;33 34 // observers35 constexpr pointer get() const noexcept;36 constexpr reference operator*() const;37 constexpr pointer operator->() const noexcept;38 constexpr explicit operator bool() const noexcept;39 40 // conversions41 constexpr explicit operator pointer() const noexcept;42 43 // modifiers44 constexpr pointer release() noexcept;45 constexpr void reset(pointer = nullptr) noexcept;46 constexpr void swap(observer_ptr&) noexcept;47};48 49}50*/51 52#if __cplusplus < 201103L && defined(_LIBCPP_USE_FROZEN_CXX03_HEADERS)53# include <__cxx03/__config>54#else55# include <__config>56# include <__cstddef/nullptr_t.h>57# include <__cstddef/size_t.h>58# include <__functional/hash.h>59# include <__functional/operations.h>60# include <__type_traits/add_pointer.h>61# include <__type_traits/add_reference.h>62# include <__type_traits/common_type.h>63# include <__type_traits/enable_if.h>64# include <__type_traits/is_convertible.h>65# include <version>66 67# if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)68# pragma GCC system_header69# endif70 71# ifdef _LIBCPP_ENABLE_EXPERIMENTAL72 73_LIBCPP_BEGIN_NAMESPACE_LFTS_V274 75# if _LIBCPP_STD_VER >= 1776 77template <class _Wp>78class observer_ptr {79public:80 using element_type = _Wp;81 82 // constructors83 _LIBCPP_HIDE_FROM_ABI constexpr observer_ptr() noexcept : __ptr_(nullptr) {}84 _LIBCPP_HIDE_FROM_ABI constexpr observer_ptr(nullptr_t) noexcept : __ptr_(nullptr) {}85 _LIBCPP_HIDE_FROM_ABI constexpr explicit observer_ptr(element_type* __p) noexcept : __ptr_(__p) {}86 87 template <class _W2, __enable_if_t<is_convertible<_W2*, _Wp*>::value, int> = 0>88 _LIBCPP_HIDE_FROM_ABI constexpr observer_ptr(observer_ptr<_W2> __other) noexcept : __ptr_(__other.get()) {}89 90 // observers91 _LIBCPP_HIDE_FROM_ABI constexpr element_type* get() const noexcept { return __ptr_; }92 _LIBCPP_HIDE_FROM_ABI constexpr add_lvalue_reference_t<_Wp> operator*() const { return *__ptr_; }93 _LIBCPP_HIDE_FROM_ABI constexpr element_type* operator->() const noexcept { return __ptr_; }94 _LIBCPP_HIDE_FROM_ABI constexpr explicit operator bool() const noexcept { return __ptr_ != nullptr; }95 96 // conversions97 _LIBCPP_HIDE_FROM_ABI constexpr explicit operator element_type*() const noexcept { return __ptr_; }98 99 // modifiers100 _LIBCPP_HIDE_FROM_ABI constexpr void reset(element_type* __p = nullptr) noexcept { __ptr_ = __p; }101 _LIBCPP_HIDE_FROM_ABI constexpr void swap(observer_ptr& __other) noexcept {102 observer_ptr __tmp = __other;103 __other = *this;104 *this = __tmp;105 }106 _LIBCPP_HIDE_FROM_ABI constexpr element_type* release() noexcept {107 observer_ptr __p;108 __p.swap(*this);109 return __p.get();110 }111 112private:113 element_type* __ptr_;114};115 116// specializations117 118template <class _Wp>119_LIBCPP_HIDE_FROM_ABI constexpr void swap(observer_ptr<_Wp>& __a, observer_ptr<_Wp>& __b) noexcept {120 __a.swap(__b);121}122 123template <class _Wp>124_LIBCPP_HIDE_FROM_ABI observer_ptr<_Wp> make_observer(_Wp* __ptr) noexcept {125 return observer_ptr<_Wp>{__ptr};126}127 128template <class _W1, class _W2>129_LIBCPP_HIDE_FROM_ABI bool operator==(observer_ptr<_W1> __a, observer_ptr<_W2> __b) {130 return __a.get() == __b.get();131}132 133template <class _W1, class _W2>134_LIBCPP_HIDE_FROM_ABI bool operator!=(observer_ptr<_W1> __a, observer_ptr<_W2> __b) {135 return !(__a == __b);136}137 138template <class _Wp>139_LIBCPP_HIDE_FROM_ABI bool operator==(observer_ptr<_Wp> __p, nullptr_t) {140 return !__p;141}142 143template <class _Wp>144_LIBCPP_HIDE_FROM_ABI bool operator==(nullptr_t, observer_ptr<_Wp> __p) {145 return !__p;146}147 148template <class _Wp>149_LIBCPP_HIDE_FROM_ABI bool operator!=(observer_ptr<_Wp> __p, nullptr_t) {150 return (bool)__p;151}152 153template <class _Wp>154_LIBCPP_HIDE_FROM_ABI bool operator!=(nullptr_t, observer_ptr<_Wp> __p) {155 return (bool)__p;156}157 158template <class _W1, class _W2>159_LIBCPP_HIDE_FROM_ABI bool operator<(observer_ptr<_W1> __a, observer_ptr<_W2> __b) {160 return std::less<typename std::common_type<_W1*, _W2*>::type>()(__a.get(), __b.get());161}162 163template <class _W1, class _W2>164_LIBCPP_HIDE_FROM_ABI bool operator>(observer_ptr<_W1> __a, observer_ptr<_W2> __b) {165 return __b < __a;166}167 168template <class _W1, class _W2>169_LIBCPP_HIDE_FROM_ABI bool operator<=(observer_ptr<_W1> __a, observer_ptr<_W2> __b) {170 return !(__a > __b);171}172 173template <class _W1, class _W2>174_LIBCPP_HIDE_FROM_ABI bool operator>=(observer_ptr<_W1> __a, observer_ptr<_W2> __b) {175 return !(__a < __b);176}177 178# endif // _LIBCPP_STD_VER >= 17179 180_LIBCPP_END_NAMESPACE_LFTS_V2181 182_LIBCPP_BEGIN_NAMESPACE_STD183 184// hash185 186# if _LIBCPP_STD_VER >= 17187template <class _Tp>188struct hash<experimental::observer_ptr<_Tp>> {189 _LIBCPP_HIDE_FROM_ABI size_t operator()(const experimental::observer_ptr<_Tp>& __ptr) const noexcept {190 return hash<_Tp*>()(__ptr.get());191 }192};193# endif // _LIBCPP_STD_VER >= 17194 195_LIBCPP_END_NAMESPACE_STD196 197# endif // _LIBCPP_ENABLE_EXPERIMENTAL198 199# if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20200# include <cstddef>201# include <limits>202# endif203#endif // __cplusplus < 201103L && defined(_LIBCPP_USE_FROZEN_CXX03_HEADERS)204 205#endif /* _LIBCPP_EXPERIMENTAL_MEMORY */206