1/*
2 * Copyright (C) 2012, 2013 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 COMPUTER, INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 *
25 */
26
27#include "config.h"
28#include "core/dom/ElementDataCache.h"
29
30#include "core/dom/ElementData.h"
31
32namespace blink {
33
34DEFINE_EMPTY_DESTRUCTOR_WILL_BE_REMOVED(ElementDataCache)
35
36inline unsigned attributeHash(const Vector<Attribute>& attributes)
37{
38    return StringHasher::hashMemory(attributes.data(), attributes.size() * sizeof(Attribute));
39}
40
41inline bool hasSameAttributes(const Vector<Attribute>& attributes, ShareableElementData& elementData)
42{
43    if (attributes.size() != elementData.attributes().size())
44        return false;
45    return !memcmp(attributes.data(), elementData.m_attributeArray, attributes.size() * sizeof(Attribute));
46}
47
48PassRefPtrWillBeRawPtr<ShareableElementData> ElementDataCache::cachedShareableElementDataWithAttributes(const Vector<Attribute>& attributes)
49{
50    ASSERT(!attributes.isEmpty());
51
52    ShareableElementDataCache::ValueType* it = m_shareableElementDataCache.add(attributeHash(attributes), nullptr).storedValue;
53
54    // FIXME: This prevents sharing when there's a hash collision.
55    if (it->value && !hasSameAttributes(attributes, *it->value))
56        return ShareableElementData::createWithAttributes(attributes);
57
58    if (!it->value)
59        it->value = ShareableElementData::createWithAttributes(attributes);
60
61    return it->value.get();
62}
63
64ElementDataCache::ElementDataCache()
65{
66}
67
68void ElementDataCache::trace(Visitor* visitor)
69{
70#if ENABLE(OILPAN)
71    visitor->trace(m_shareableElementDataCache);
72#endif
73}
74
75}
76