1 | /* |
2 | * Copyright (C) 1999 Lars Knoll (knoll@kde.org) |
3 | * (C) 1999 Antti Koivisto (koivisto@kde.org) |
4 | * (C) 2001 Dirk Mueller (mueller@kde.org) |
5 | * Copyright (C) 2004-2017 Apple Inc. All rights reserved. |
6 | * |
7 | * This library is free software; you can redistribute it and/or |
8 | * modify it under the terms of the GNU Library General Public |
9 | * License as published by the Free Software Foundation; either |
10 | * version 2 of the License, or (at your option) any later version. |
11 | * |
12 | * This library is distributed in the hope that it will be useful, |
13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
15 | * Library General Public License for more details. |
16 | * |
17 | * You should have received a copy of the GNU Library General Public License |
18 | * along with this library; see the file COPYING.LIB. If not, write to |
19 | * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, |
20 | * Boston, MA 02110-1301, USA. |
21 | * |
22 | */ |
23 | |
24 | #pragma once |
25 | |
26 | #include "CollectionIndexCache.h" |
27 | #include "NodeList.h" |
28 | #include <wtf/IsoMalloc.h> |
29 | #include <wtf/Ref.h> |
30 | |
31 | namespace WebCore { |
32 | |
33 | class ContainerNode; |
34 | |
35 | class EmptyNodeList final : public NodeList { |
36 | WTF_MAKE_ISO_ALLOCATED(EmptyNodeList); |
37 | public: |
38 | static Ref<EmptyNodeList> create(Node& owner) |
39 | { |
40 | return adoptRef(*new EmptyNodeList(owner)); |
41 | } |
42 | virtual ~EmptyNodeList(); |
43 | |
44 | Node& ownerNode() { return m_owner; } |
45 | |
46 | private: |
47 | explicit EmptyNodeList(Node& owner) : m_owner(owner) { } |
48 | |
49 | unsigned length() const override { return 0; } |
50 | Node* item(unsigned) const override { return nullptr; } |
51 | size_t memoryCost() const override { return 0; } |
52 | |
53 | bool isEmptyNodeList() const override { return true; } |
54 | |
55 | Ref<Node> m_owner; |
56 | }; |
57 | |
58 | class ChildNodeList final : public NodeList { |
59 | WTF_MAKE_ISO_ALLOCATED(ChildNodeList); |
60 | public: |
61 | static Ref<ChildNodeList> create(ContainerNode& parent) |
62 | { |
63 | return adoptRef(*new ChildNodeList(parent)); |
64 | } |
65 | |
66 | virtual ~ChildNodeList(); |
67 | |
68 | ContainerNode& ownerNode() { return m_parent; } |
69 | |
70 | void invalidateCache(); |
71 | |
72 | // For CollectionIndexCache |
73 | Node* collectionBegin() const; |
74 | Node* collectionLast() const; |
75 | Node* collectionEnd() const { return nullptr; } |
76 | void collectionTraverseForward(Node*&, unsigned count, unsigned& traversedCount) const; |
77 | void collectionTraverseBackward(Node*&, unsigned count) const; |
78 | bool collectionCanTraverseBackward() const { return true; } |
79 | void willValidateIndexCache() const { } |
80 | |
81 | private: |
82 | explicit ChildNodeList(ContainerNode& parent); |
83 | |
84 | unsigned length() const override; |
85 | Node* item(unsigned index) const override; |
86 | size_t memoryCost() const override |
87 | { |
88 | // memoryCost() may be invoked concurrently from a GC thread, and we need to be careful |
89 | // about what data we access here and how. Accessing m_indexCache is safe because |
90 | // because it doesn't involve any pointer chasing. |
91 | return m_indexCache.memoryCost(); |
92 | } |
93 | |
94 | bool isChildNodeList() const override { return true; } |
95 | |
96 | Ref<ContainerNode> m_parent; |
97 | mutable CollectionIndexCache<ChildNodeList, Node*> m_indexCache; |
98 | }; |
99 | |
100 | } // namespace WebCore |
101 | |