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___NODE_HANDLE
11#define _LIBCPP___NODE_HANDLE
12
13/*
14
15template<unspecified>
16class node-handle {
17public:
18  using value_type     = see below;     // not present for map containers
19  using key_type       = see below;     // not present for set containers
20  using mapped_type    = see below;     // not present for set containers
21  using allocator_type = see below;
22
23private:
24  using container_node_type = unspecified;                  // exposition only
25  using ator_traits = allocator_traits<allocator_type>;     // exposition only
26
27  typename ator_traits::template
28    rebind_traits<container_node_type>::pointer ptr_;       // exposition only
29  optional<allocator_type> alloc_;                          // exposition only
30
31public:
32  // [container.node.cons], constructors, copy, and assignment
33  constexpr node-handle() noexcept : ptr_(), alloc_() {}
34  node-handle(node-handle&&) noexcept;
35  node-handle& operator=(node-handle&&);
36
37  // [container.node.dtor], destructor
38  ~node-handle();
39
40  // [container.node.observers], observers
41  value_type& value() const;            // not present for map containers
42  key_type& key() const;                // not present for set containers
43  mapped_type& mapped() const;          // not present for set containers
44
45  allocator_type get_allocator() const;
46  explicit operator bool() const noexcept;
47  [[nodiscard]] bool empty() const noexcept; // nodiscard since C++20
48
49  // [container.node.modifiers], modifiers
50  void swap(node-handle&)
51    noexcept(ator_traits::propagate_on_container_swap::value ||
52             ator_traits::is_always_equal::value);
53
54  friend void swap(node-handle& x, node-handle& y) noexcept(noexcept(x.swap(y))) {
55    x.swap(y);
56  }
57};
58
59*/
60
61#include <__config>
62#include <__debug>
63#include <memory>
64#include <optional>
65
66#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
67#pragma GCC system_header
68#endif
69
70_LIBCPP_BEGIN_NAMESPACE_STD
71
72#if _LIBCPP_STD_VER > 14
73
74// Specialized in __tree & __hash_table for their _NodeType.
75template <class _NodeType, class _Alloc>
76struct __generic_container_node_destructor;
77
78template <class _NodeType, class _Alloc,
79          template <class, class> class _MapOrSetSpecifics>
80class _LIBCPP_TEMPLATE_VIS __basic_node_handle
81    : public _MapOrSetSpecifics<
82          _NodeType,
83          __basic_node_handle<_NodeType, _Alloc, _MapOrSetSpecifics>>
84{
85    template <class _Tp, class _Compare, class _Allocator>
86        friend class __tree;
87    template <class _Tp, class _Hash, class _Equal, class _Allocator>
88        friend class __hash_table;
89    friend struct _MapOrSetSpecifics<
90        _NodeType, __basic_node_handle<_NodeType, _Alloc, _MapOrSetSpecifics>>;
91
92    typedef allocator_traits<_Alloc> __alloc_traits;
93    typedef typename __rebind_pointer<typename __alloc_traits::void_pointer,
94                                      _NodeType>::type
95        __node_pointer_type;
96
97public:
98    typedef _Alloc allocator_type;
99
100private:
101    __node_pointer_type __ptr_ = nullptr;
102    optional<allocator_type> __alloc_;
103
104    _LIBCPP_INLINE_VISIBILITY
105    void __release_ptr()
106    {
107        __ptr_ = nullptr;
108        __alloc_ = _VSTD::nullopt;
109    }
110
111    _LIBCPP_INLINE_VISIBILITY
112    void __destroy_node_pointer()
113    {
114        if (__ptr_ != nullptr)
115        {
116            typedef typename __allocator_traits_rebind<
117                allocator_type, _NodeType>::type __node_alloc_type;
118            __node_alloc_type __alloc(*__alloc_);
119            __generic_container_node_destructor<_NodeType, __node_alloc_type>(
120                __alloc, true)(__ptr_);
121            __ptr_ = nullptr;
122        }
123    }
124
125    _LIBCPP_INLINE_VISIBILITY
126    __basic_node_handle(__node_pointer_type __ptr,
127                        allocator_type const& __alloc)
128            : __ptr_(__ptr), __alloc_(__alloc)
129    {
130    }
131
132public:
133    _LIBCPP_INLINE_VISIBILITY
134    __basic_node_handle() = default;
135
136    _LIBCPP_INLINE_VISIBILITY
137    __basic_node_handle(__basic_node_handle&& __other) noexcept
138            : __ptr_(__other.__ptr_),
139              __alloc_(_VSTD::move(__other.__alloc_))
140    {
141        __other.__ptr_ = nullptr;
142        __other.__alloc_ = _VSTD::nullopt;
143    }
144
145    _LIBCPP_INLINE_VISIBILITY
146    __basic_node_handle& operator=(__basic_node_handle&& __other)
147    {
148        _LIBCPP_ASSERT(
149            __alloc_ == _VSTD::nullopt ||
150            __alloc_traits::propagate_on_container_move_assignment::value ||
151            __alloc_ == __other.__alloc_,
152            "node_type with incompatible allocator passed to "
153            "node_type::operator=(node_type&&)");
154
155        __destroy_node_pointer();
156        __ptr_ = __other.__ptr_;
157
158        if (__alloc_traits::propagate_on_container_move_assignment::value ||
159            __alloc_ == _VSTD::nullopt)
160            __alloc_ = _VSTD::move(__other.__alloc_);
161
162        __other.__ptr_ = nullptr;
163        __other.__alloc_ = _VSTD::nullopt;
164
165        return *this;
166    }
167
168    _LIBCPP_INLINE_VISIBILITY
169    allocator_type get_allocator() const { return *__alloc_; }
170
171    _LIBCPP_INLINE_VISIBILITY
172    explicit operator bool() const { return __ptr_ != nullptr; }
173
174    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY
175    bool empty() const { return __ptr_ == nullptr; }
176
177    _LIBCPP_INLINE_VISIBILITY
178    void swap(__basic_node_handle& __other) noexcept(
179        __alloc_traits::propagate_on_container_swap::value ||
180        __alloc_traits::is_always_equal::value)
181    {
182        using _VSTD::swap;
183        swap(__ptr_, __other.__ptr_);
184        if (__alloc_traits::propagate_on_container_swap::value ||
185            __alloc_ == _VSTD::nullopt || __other.__alloc_ == _VSTD::nullopt)
186            swap(__alloc_, __other.__alloc_);
187    }
188
189    _LIBCPP_INLINE_VISIBILITY
190    friend void swap(__basic_node_handle& __a, __basic_node_handle& __b)
191        noexcept(noexcept(__a.swap(__b))) { __a.swap(__b); }
192
193    _LIBCPP_INLINE_VISIBILITY
194    ~__basic_node_handle()
195    {
196        __destroy_node_pointer();
197    }
198};
199
200template <class _NodeType, class _Derived>
201struct __set_node_handle_specifics
202{
203    typedef typename _NodeType::__node_value_type value_type;
204
205    _LIBCPP_INLINE_VISIBILITY
206    value_type& value() const
207    {
208        return static_cast<_Derived const*>(this)->__ptr_->__value_;
209    }
210};
211
212template <class _NodeType, class _Derived>
213struct __map_node_handle_specifics
214{
215    typedef typename _NodeType::__node_value_type::key_type key_type;
216    typedef typename _NodeType::__node_value_type::mapped_type mapped_type;
217
218    _LIBCPP_INLINE_VISIBILITY
219    key_type& key() const
220    {
221        return static_cast<_Derived const*>(this)->
222            __ptr_->__value_.__ref().first;
223    }
224
225    _LIBCPP_INLINE_VISIBILITY
226    mapped_type& mapped() const
227    {
228        return static_cast<_Derived const*>(this)->
229            __ptr_->__value_.__ref().second;
230    }
231};
232
233template <class _NodeType, class _Alloc>
234using __set_node_handle =
235    __basic_node_handle< _NodeType, _Alloc, __set_node_handle_specifics>;
236
237template <class _NodeType, class _Alloc>
238using __map_node_handle =
239    __basic_node_handle< _NodeType, _Alloc, __map_node_handle_specifics>;
240
241template <class _Iterator, class _NodeType>
242struct _LIBCPP_TEMPLATE_VIS __insert_return_type
243{
244    _Iterator position;
245    bool inserted;
246    _NodeType node;
247};
248
249#endif // _LIBCPP_STD_VER > 14
250
251_LIBCPP_END_NAMESPACE_STD
252
253#endif  // _LIBCPP___NODE_HANDLE
254