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
|
/*
* Copyright (C) 2012, 2013 Apple Inc. All Rights Reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE COMPUTER, INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
#include "core/dom/ElementDataCache.h"
#include "core/dom/ElementData.h"
namespace blink {
inline unsigned attributeHash(const Vector<Attribute>& attributes) {
return StringHasher::hashMemory(attributes.data(),
attributes.size() * sizeof(Attribute));
}
inline bool hasSameAttributes(const Vector<Attribute>& attributes,
ShareableElementData& elementData) {
if (attributes.size() != elementData.attributes().size())
return false;
return !memcmp(attributes.data(), elementData.m_attributeArray,
attributes.size() * sizeof(Attribute));
}
ShareableElementData*
ElementDataCache::cachedShareableElementDataWithAttributes(
const Vector<Attribute>& attributes) {
DCHECK(!attributes.isEmpty());
ShareableElementDataCache::ValueType* it =
m_shareableElementDataCache.add(attributeHash(attributes), nullptr)
.storedValue;
// FIXME: This prevents sharing when there's a hash collision.
if (it->value && !hasSameAttributes(attributes, *it->value))
return ShareableElementData::createWithAttributes(attributes);
if (!it->value)
it->value = ShareableElementData::createWithAttributes(attributes);
return it->value.get();
}
ElementDataCache::ElementDataCache() {}
DEFINE_TRACE(ElementDataCache) {
visitor->trace(m_shareableElementDataCache);
}
} // namespace blink
|
