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1 // Copyright 2015 The Chromium Authors. All rights reserved. | |
2 // Use of this source code is governed by a BSD-style license that can be | |
3 // found in the LICENSE file. | |
4 | |
5 #ifndef NthIndexCache_h | |
6 #define NthIndexCache_h | |
7 | |
8 #include "core/dom/Element.h" | |
9 #include "core/dom/ElementTraversal.h" | |
10 #include "platform/heap/Handle.h" | |
11 #include "wtf/HashMap.h" | |
12 #include "wtf/RefPtr.h" | |
13 | |
14 namespace blink { | |
15 | |
16 class Document; | |
17 | |
18 class NthIndexCache : NoBaseWillBeGarbageCollected<NthIndexCache> { | |
19 WTF_MAKE_NONCOPYABLE(NthIndexCache); | |
20 public: | |
21 NthIndexCache(Document& document) | |
22 : m_document(document) { } | |
23 | |
24 unsigned nthChildIndex(Element&); | |
25 unsigned nthLastChildIndex(Element&); | |
26 | |
27 void clear(); | |
28 | |
29 DECLARE_TRACE(); | |
30 | |
31 private: | |
32 class NthIndexData : public NoBaseWillBeGarbageCollected<NthIndexData> { | |
33 WTF_MAKE_NONCOPYABLE(NthIndexData); | |
34 public: | |
35 NthIndexData() : m_count(0) { } | |
36 | |
37 inline unsigned nthIndex(Element&); | |
38 inline unsigned nthLastIndex(Element&); | |
39 | |
40 unsigned cacheNthIndices(Element&); | |
41 | |
42 WillBeHeapHashMap<RawPtrWillBeMember<Element>, unsigned> m_elementIndexM ap; | |
43 unsigned m_count; | |
44 | |
45 DECLARE_TRACE(); | |
46 }; | |
47 | |
48 NthIndexData& ensureNthIndexDataFor(Node&); | |
49 inline unsigned nthIndex(Element&); | |
50 | |
51 typedef WillBeHeapHashMap<RefPtrWillBeMember<Node>, OwnPtrWillBeMember<NthIn dexData>> ParentMap; | |
sof
2015/03/28 08:33:59
nit: "using" is preferred over "typedef" now.
rune
2015/03/30 09:00:03
Done.
| |
52 | |
53 OwnPtrWillBeMember<ParentMap> m_parentMap; | |
54 Document& m_document; | |
sof
2015/03/28 08:33:59
Make this a RawPtrWillBeMember<Document> and have
rune
2015/03/30 09:00:03
Done.
| |
55 }; | |
56 | |
57 inline unsigned NthIndexCache::NthIndexData::nthIndex(Element& element) | |
58 { | |
59 if (!m_count) | |
60 return cacheNthIndices(element); | |
61 | |
62 unsigned index = 0; | |
63 for (Element* sibling = &element; sibling; sibling = ElementTraversal::previ ousSibling(*sibling), index++) { | |
64 auto it = m_elementIndexMap.find(sibling); | |
65 if (it != m_elementIndexMap.end()) | |
66 return it->value + index; | |
67 } | |
68 return index; | |
69 } | |
70 | |
71 inline unsigned NthIndexCache::NthIndexData::nthLastIndex(Element& element) | |
72 { | |
73 unsigned index = nthIndex(element); | |
74 return m_count - index + 1; | |
75 } | |
76 | |
77 inline unsigned NthIndexCache::nthChildIndex(Element& element) | |
78 { | |
79 ASSERT(element.parentNode()); | |
80 return ensureNthIndexDataFor(*element.parentNode()).nthIndex(element); | |
81 } | |
82 | |
83 inline unsigned NthIndexCache::nthLastChildIndex(Element& element) | |
84 { | |
85 ASSERT(element.parentNode()); | |
86 return ensureNthIndexDataFor(*element.parentNode()).nthLastIndex(element); | |
87 } | |
88 | |
89 } // namespace blink | |
90 | |
91 #endif // NthIndexCache_h | |
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