1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
|
/*
* Copyright (C) 1999 Lars Knoll (knoll@kde.org)
* (C) 1999 Antti Koivisto (koivisto@kde.org)
* (C) 2001 Dirk Mueller (mueller@kde.org)
* Copyright (C) 2004-2017 Apple Inc. All rights reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public License
* along with this library; see the file COPYING.LIB. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
*
*/
#pragma once
#include "CollectionIndexCache.h"
#include "NodeList.h"
#include <wtf/CheckedRef.h>
#include <wtf/Ref.h>
#include <wtf/TZoneMalloc.h>
#include <wtf/WeakPtr.h>
namespace WebCore {
class ContainerNode;
class EmptyNodeList final : public NodeList, public CanMakeSingleThreadWeakPtr<EmptyNodeList> {
WTF_MAKE_TZONE_OR_ISO_ALLOCATED(EmptyNodeList);
public:
static Ref<EmptyNodeList> create(Node& owner)
{
return adoptRef(*new EmptyNodeList(owner));
}
virtual ~EmptyNodeList();
Node& ownerNode() { return m_owner; }
private:
explicit EmptyNodeList(Node& owner) : m_owner(owner) { }
unsigned length() const override { return 0; }
Node* item(unsigned) const override { return nullptr; }
size_t memoryCost() const override { return 0; }
bool isEmptyNodeList() const override { return true; }
Ref<Node> m_owner;
};
class ChildNodeList final : public NodeList, public CanMakeSingleThreadWeakPtr<ChildNodeList> {
WTF_MAKE_TZONE_OR_ISO_ALLOCATED(ChildNodeList);
public:
static Ref<ChildNodeList> create(ContainerNode& parent)
{
return adoptRef(*new ChildNodeList(parent));
}
virtual ~ChildNodeList();
ContainerNode& ownerNode() { return m_parent; }
void invalidateCache();
// For CollectionIndexCache
Node* collectionBegin() const;
Node* collectionLast() const;
void collectionTraverseForward(Node*&, unsigned count, unsigned& traversedCount) const;
void collectionTraverseBackward(Node*&, unsigned count) const;
bool collectionCanTraverseBackward() const { return true; }
void willValidateIndexCache() const { }
private:
explicit ChildNodeList(ContainerNode& parent);
unsigned length() const override;
Node* item(unsigned index) const override;
size_t memoryCost() const override
{
// memoryCost() may be invoked concurrently from a GC thread, and we need to be careful
// about what data we access here and how. Accessing m_indexCache is safe because
// because it doesn't involve any pointer chasing.
return m_indexCache.memoryCost();
}
bool isChildNodeList() const override { return true; }
Ref<ContainerNode> m_parent;
mutable CollectionIndexCache<ChildNodeList, Node*> m_indexCache;
};
} // namespace WebCore
|
