1/*
2 * Copyright (C) 2013-2019 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
14 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
15 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
17 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
18 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
19 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
20 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
21 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
22 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
23 * THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#pragma once
27
28#include <wtf/DumbPtrTraits.h>
29#include <wtf/FastMalloc.h>
30#include <wtf/Noncopyable.h>
31#include <wtf/Packed.h>
32
33namespace WTF {
34
35namespace Private {
36
37template<typename T, typename PassedPtrTraits = DumbPtrTraits<T>>
38class BagNode {
39 WTF_MAKE_FAST_ALLOCATED;
40public:
41 using PtrTraits = typename PassedPtrTraits::template RebindTraits<BagNode>;
42
43 template<typename... Args>
44 BagNode(Args&&... args)
45 : m_item(std::forward<Args>(args)...)
46 { }
47
48 T m_item;
49 typename PtrTraits::StorageType m_next { nullptr };
50};
51
52} // namespace Private
53
54template<typename T, typename PassedPtrTraits = DumbPtrTraits<T>>
55class Bag {
56 WTF_MAKE_NONCOPYABLE(Bag);
57 WTF_MAKE_FAST_ALLOCATED;
58 using Node = Private::BagNode<T, PassedPtrTraits>;
59 using PtrTraits = typename PassedPtrTraits::template RebindTraits<Node>;
60
61public:
62 Bag() = default;
63
64 template<typename U>
65 Bag(Bag<T, U>&& other)
66 {
67 ASSERT(!m_head);
68 m_head = other.unwrappedHead();
69 other.m_head = nullptr;
70 }
71
72 ~Bag()
73 {
74 clear();
75 }
76
77 void clear()
78 {
79 Node* head = this->unwrappedHead();
80 while (head) {
81 Node* current = head;
82 head = Node::PtrTraits::unwrap(current->m_next);
83 delete current;
84 }
85 m_head = nullptr;
86 }
87
88 template<typename... Args>
89 T* add(Args&&... args)
90 {
91 Node* newNode = new Node(std::forward<Args>(args)...);
92 newNode->m_next = unwrappedHead();
93 m_head = newNode;
94 return &newNode->m_item;
95 }
96
97 class iterator {
98 public:
99 iterator()
100 : m_node(0)
101 {
102 }
103
104 // This is sort of cheating; it's equivalent to iter == end().
105 bool operator!() const { return !m_node; }
106
107 T* operator*() const { return &m_node->m_item; }
108
109 iterator& operator++()
110 {
111 m_node = Node::PtrTraits::unwrap(m_node->m_next);
112 return *this;
113 }
114
115 bool operator==(const iterator& other) const
116 {
117 return m_node == other.m_node;
118 }
119
120 bool operator!=(const iterator& other) const
121 {
122 return !(*this == other);
123 }
124
125 private:
126 template<typename, typename> friend class WTF::Bag;
127 Node* m_node;
128 };
129
130 iterator begin()
131 {
132 iterator result;
133 result.m_node = unwrappedHead();
134 return result;
135 }
136
137 const iterator begin() const
138 {
139 iterator result;
140 result.m_node = unwrappedHead();
141 return result;
142 }
143
144
145 iterator end() const { return iterator(); }
146
147 bool isEmpty() const { return !m_head; }
148
149private:
150 Node* unwrappedHead() const { return PtrTraits::unwrap(m_head); }
151
152 typename PtrTraits::StorageType m_head { nullptr };
153};
154
155template<typename T>
156using PackedBag = Bag<T, PackedPtrTraits<T>>;
157
158} // namespace WTF
159
160using WTF::Bag;
161using WTF::PackedBag;
162