1/*
2 * Copyright (C) 2015-2019 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 "CollectionTraversal.h"
29#include "HTMLCollection.h"
30#include "HTMLElement.h"
31#include <wtf/IsoMalloc.h>
32
33namespace WebCore {
34
35template <typename HTMLCollectionClass, CollectionTraversalType traversalType>
36class CachedHTMLCollection : public HTMLCollection {
37 WTF_MAKE_ISO_NONALLOCATABLE(CachedHTMLCollection);
38public:
39 CachedHTMLCollection(ContainerNode& base, CollectionType);
40
41 virtual ~CachedHTMLCollection();
42
43 unsigned length() const final { return m_indexCache.nodeCount(collection()); }
44 Element* item(unsigned offset) const override { return m_indexCache.nodeAt(collection(), offset); }
45 Element* namedItem(const AtomicString& name) const override;
46 size_t memoryCost() const final
47 {
48 // memoryCost() may be invoked concurrently from a GC thread, and we need to be careful about what data we access here and how.
49 // Accessing m_indexCache.memoryCost() is safe because because it doesn't involve any pointer chasing.
50 // HTMLCollection::memoryCost() ensures its own thread safety.
51 return m_indexCache.memoryCost() + HTMLCollection::memoryCost();
52 }
53
54 // For CollectionIndexCache; do not use elsewhere.
55 using CollectionTraversalIterator = typename CollectionTraversal<traversalType>::Iterator;
56 CollectionTraversalIterator collectionBegin() const { return CollectionTraversal<traversalType>::begin(collection(), rootNode()); }
57 CollectionTraversalIterator collectionLast() const { return CollectionTraversal<traversalType>::last(collection(), rootNode()); }
58 CollectionTraversalIterator collectionEnd() const { return CollectionTraversal<traversalType>::end(rootNode()); }
59 void collectionTraverseForward(CollectionTraversalIterator& current, unsigned count, unsigned& traversedCount) const { CollectionTraversal<traversalType>::traverseForward(collection(), current, count, traversedCount); }
60 void collectionTraverseBackward(CollectionTraversalIterator& current, unsigned count) const { CollectionTraversal<traversalType>::traverseBackward(collection(), current, count); }
61 bool collectionCanTraverseBackward() const { return traversalType != CollectionTraversalType::CustomForwardOnly; }
62 void willValidateIndexCache() const { document().registerCollection(const_cast<CachedHTMLCollection<HTMLCollectionClass, traversalType>&>(*this)); }
63
64 void invalidateCacheForDocument(Document&) override;
65
66 bool elementMatches(Element&) const;
67
68private:
69 HTMLCollectionClass& collection() { return static_cast<HTMLCollectionClass&>(*this); }
70 const HTMLCollectionClass& collection() const { return static_cast<const HTMLCollectionClass&>(*this); }
71
72 mutable CollectionIndexCache<HTMLCollectionClass, CollectionTraversalIterator> m_indexCache;
73};
74
75template <typename HTMLCollectionClass, CollectionTraversalType traversalType>
76CachedHTMLCollection<HTMLCollectionClass, traversalType>::CachedHTMLCollection(ContainerNode& base, CollectionType collectionType)
77 : HTMLCollection(base, collectionType)
78 , m_indexCache(collection())
79{ }
80
81template <typename HTMLCollectionClass, CollectionTraversalType traversalType>
82CachedHTMLCollection<HTMLCollectionClass, traversalType>::~CachedHTMLCollection()
83{
84 if (m_indexCache.hasValidCache(collection()))
85 document().unregisterCollection(*this);
86}
87
88template <typename HTMLCollectionClass, CollectionTraversalType traversalType>
89void CachedHTMLCollection<HTMLCollectionClass, traversalType>::invalidateCacheForDocument(Document& document)
90{
91 HTMLCollection::invalidateCacheForDocument(document);
92 if (m_indexCache.hasValidCache(collection())) {
93 document.unregisterCollection(*this);
94 m_indexCache.invalidate(collection());
95 }
96}
97
98template <typename HTMLCollectionClass, CollectionTraversalType traversalType>
99bool CachedHTMLCollection<HTMLCollectionClass, traversalType>::elementMatches(Element&) const
100{
101 // We call the elementMatches() method directly on the subclass instead for performance.
102 ASSERT_NOT_REACHED();
103 return false;
104}
105
106static inline bool nameShouldBeVisibleInDocumentAll(HTMLElement& element)
107{
108 // https://html.spec.whatwg.org/multipage/infrastructure.html#all-named-elements
109 return element.hasTagName(HTMLNames::aTag)
110 || element.hasTagName(HTMLNames::appletTag)
111 || element.hasTagName(HTMLNames::buttonTag)
112 || element.hasTagName(HTMLNames::embedTag)
113 || element.hasTagName(HTMLNames::formTag)
114 || element.hasTagName(HTMLNames::frameTag)
115 || element.hasTagName(HTMLNames::framesetTag)
116 || element.hasTagName(HTMLNames::iframeTag)
117 || element.hasTagName(HTMLNames::imgTag)
118 || element.hasTagName(HTMLNames::inputTag)
119 || element.hasTagName(HTMLNames::mapTag)
120 || element.hasTagName(HTMLNames::metaTag)
121 || element.hasTagName(HTMLNames::objectTag)
122 || element.hasTagName(HTMLNames::selectTag)
123 || element.hasTagName(HTMLNames::textareaTag);
124}
125
126static inline bool nameShouldBeVisibleInDocumentAll(Element& element)
127{
128 return is<HTMLElement>(element) && nameShouldBeVisibleInDocumentAll(downcast<HTMLElement>(element));
129}
130
131template <typename HTMLCollectionClass, CollectionTraversalType traversalType>
132Element* CachedHTMLCollection<HTMLCollectionClass, traversalType>::namedItem(const AtomicString& name) const
133{
134 // http://msdn.microsoft.com/workshop/author/dhtml/reference/methods/nameditem.asp
135 // This method first searches for an object with a matching id
136 // attribute. If a match is not found, the method then searches for an
137 // object with a matching name attribute, but only on those elements
138 // that are allowed a name attribute.
139
140 if (name.isEmpty())
141 return nullptr;
142
143 ContainerNode& root = rootNode();
144 if (traversalType != CollectionTraversalType::CustomForwardOnly && root.isInTreeScope()) {
145 Element* candidate = nullptr;
146
147 TreeScope& treeScope = root.treeScope();
148 if (treeScope.hasElementWithId(*name.impl())) {
149 if (!treeScope.containsMultipleElementsWithId(name))
150 candidate = treeScope.getElementById(name);
151 } else if (treeScope.hasElementWithName(*name.impl())) {
152 if (!treeScope.containsMultipleElementsWithName(name)) {
153 if ((candidate = treeScope.getElementByName(name))) {
154 if (!is<HTMLElement>(*candidate))
155 candidate = nullptr;
156 else if (type() == DocAll && !nameShouldBeVisibleInDocumentAll(*candidate))
157 candidate = nullptr;
158 }
159 }
160 } else
161 return nullptr;
162
163 if (candidate && collection().elementMatches(*candidate)) {
164 if (traversalType == CollectionTraversalType::ChildrenOnly ? candidate->parentNode() == &root : candidate->isDescendantOf(root))
165 return candidate;
166 }
167 }
168
169 return namedItemSlow(name);
170}
171
172} // namespace WebCore
173