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 32 namespace WebCore { 33 34 inline unsigned attributeHash(const Vector<Attribute>& attributes) 35 { 36 return StringHasher::hashMemory(attributes.data(), attributes.size() * sizeof(Attribute)); 37 } 38 39 inline bool hasSameAttributes(const Vector<Attribute>& attributes, ShareableElementData& elementData) 40 { 41 if (attributes.size() != elementData.attributeCount()) 42 return false; 43 return !memcmp(attributes.data(), elementData.m_attributeArray, attributes.size() * sizeof(Attribute)); 44 } 45 46 PassRefPtr<ShareableElementData> ElementDataCache::cachedShareableElementDataWithAttributes(const Vector<Attribute>& attributes) 47 { 48 ASSERT(!attributes.isEmpty()); 49 50 ShareableElementDataCache::ValueType* it = m_shareableElementDataCache.add(attributeHash(attributes), nullptr).storedValue; 51 52 // FIXME: This prevents sharing when there's a hash collision. 53 if (it->value && !hasSameAttributes(attributes, *it->value)) 54 return ShareableElementData::createWithAttributes(attributes); 55 56 if (!it->value) 57 it->value = ShareableElementData::createWithAttributes(attributes); 58 59 return it->value.get(); 60 } 61 62 ElementDataCache::ElementDataCache() 63 { 64 } 65 66 ElementDataCache::~ElementDataCache() 67 { 68 } 69 70 } 71
