1/*
2 * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
3 *           (C) 2004-2005 Allan Sandfeld Jensen (kde@carewolf.com)
4 * Copyright (C) 2006, 2007 Nicholas Shanks (webkit@nickshanks.com)
5 * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Apple Inc. All rights reserved.
6 * Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
7 * Copyright (C) 2007, 2008 Eric Seidel <eric@webkit.org>
8 * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
9 * Copyright (c) 2011, Code Aurora Forum. All rights reserved.
10 * Copyright (C) Research In Motion Limited 2011. All rights reserved.
11 * Copyright (C) 2013 Google Inc. All rights reserved.
12 *
13 * This library is free software; you can redistribute it and/or
14 * modify it under the terms of the GNU Library General Public
15 * License as published by the Free Software Foundation; either
16 * version 2 of the License, or (at your option) any later version.
17 *
18 * This library is distributed in the hope that it will be useful,
19 * but WITHOUT ANY WARRANTY; without even the implied warranty of
20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
21 * Library General Public License for more details.
22 *
23 * You should have received a copy of the GNU Library General Public License
24 * along with this library; see the file COPYING.LIB.  If not, write to
25 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
26 * Boston, MA 02110-1301, USA.
27 */
28
29#include "config.h"
30#include "core/css/resolver/MatchedPropertiesCache.h"
31
32#include "core/css/StylePropertySet.h"
33#include "core/css/resolver/StyleResolverState.h"
34#include "core/rendering/style/RenderStyle.h"
35
36namespace blink {
37
38#if ENABLE(OILPAN)
39bool CachedMatchedPropertiesHashTraits::traceInCollection(Visitor* visitor, Member<CachedMatchedProperties>& cachedProperties, WTF::ShouldWeakPointersBeMarkedStrongly strongify)
40{
41    // Only honor the cache's weakness semantics if the collection is traced
42    // with WeakPointersActWeak. Otherwise just trace the cachedProperties
43    // strongly, ie. call trace on it.
44    if (cachedProperties && strongify == WTF::WeakPointersActWeak) {
45        // A given cache entry is only kept alive if none of the MatchedProperties
46        // in the CachedMatchedProperties value contain a dead "properties" field.
47        // If there is a dead field the entire cache entry is removed.
48        HeapVector<MatchedProperties>::iterator it = cachedProperties->matchedProperties.begin();
49        HeapVector<MatchedProperties>::iterator end = cachedProperties->matchedProperties.end();
50        for (; it != end; ++it) {
51            if (!visitor->isAlive(it->properties)) {
52                // For now report the cache entry as dead. This might not
53                // be the final result if in a subsequent call for this entry,
54                // the "properties" field has been marked via another path.
55                return true;
56            }
57        }
58    }
59    // At this point none of the entries in the matchedProperties vector
60    // had a dead "properties" field so trace CachedMatchedProperties strongly.
61    visitor->trace(cachedProperties);
62    return false;
63}
64#endif
65
66void CachedMatchedProperties::set(const RenderStyle* style, const RenderStyle* parentStyle, const MatchResult& matchResult)
67{
68    matchedProperties.appendVector(matchResult.matchedProperties);
69    ranges = matchResult.ranges;
70
71    // Note that we don't cache the original RenderStyle instance. It may be further modified.
72    // The RenderStyle in the cache is really just a holder for the substructures and never used as-is.
73    this->renderStyle = RenderStyle::clone(style);
74    this->parentRenderStyle = RenderStyle::clone(parentStyle);
75}
76
77void CachedMatchedProperties::clear()
78{
79    matchedProperties.clear();
80    renderStyle = nullptr;
81    parentRenderStyle = nullptr;
82}
83
84MatchedPropertiesCache::MatchedPropertiesCache()
85#if !ENABLE(OILPAN)
86    : m_additionsSinceLastSweep(0)
87    , m_sweepTimer(this, &MatchedPropertiesCache::sweep)
88#endif
89{
90}
91
92const CachedMatchedProperties* MatchedPropertiesCache::find(unsigned hash, const StyleResolverState& styleResolverState, const MatchResult& matchResult)
93{
94    ASSERT(hash);
95
96    Cache::iterator it = m_cache.find(hash);
97    if (it == m_cache.end())
98        return 0;
99    CachedMatchedProperties* cacheItem = it->value.get();
100    ASSERT(cacheItem);
101
102    size_t size = matchResult.matchedProperties.size();
103    if (size != cacheItem->matchedProperties.size())
104        return 0;
105    if (cacheItem->renderStyle->insideLink() != styleResolverState.style()->insideLink())
106        return 0;
107    for (size_t i = 0; i < size; ++i) {
108        if (matchResult.matchedProperties[i] != cacheItem->matchedProperties[i])
109            return 0;
110    }
111    if (cacheItem->ranges != matchResult.ranges)
112        return 0;
113    return cacheItem;
114}
115
116void MatchedPropertiesCache::add(const RenderStyle* style, const RenderStyle* parentStyle, unsigned hash, const MatchResult& matchResult)
117{
118#if !ENABLE(OILPAN)
119    static const unsigned maxAdditionsBetweenSweeps = 100;
120    if (++m_additionsSinceLastSweep >= maxAdditionsBetweenSweeps
121        && !m_sweepTimer.isActive()) {
122        static const unsigned sweepTimeInSeconds = 60;
123        m_sweepTimer.startOneShot(sweepTimeInSeconds, FROM_HERE);
124    }
125#endif
126
127    ASSERT(hash);
128    Cache::AddResult addResult = m_cache.add(hash, nullptr);
129    if (addResult.isNewEntry)
130        addResult.storedValue->value = adoptPtrWillBeNoop(new CachedMatchedProperties);
131
132    CachedMatchedProperties* cacheItem = addResult.storedValue->value.get();
133    if (!addResult.isNewEntry)
134        cacheItem->clear();
135
136    cacheItem->set(style, parentStyle, matchResult);
137}
138
139void MatchedPropertiesCache::clear()
140{
141    m_cache.clear();
142}
143
144void MatchedPropertiesCache::clearViewportDependent()
145{
146    Vector<unsigned, 16> toRemove;
147    for (Cache::iterator it = m_cache.begin(); it != m_cache.end(); ++it) {
148        CachedMatchedProperties* cacheItem = it->value.get();
149        if (cacheItem->renderStyle->hasViewportUnits())
150            toRemove.append(it->key);
151    }
152    m_cache.removeAll(toRemove);
153}
154
155#if !ENABLE(OILPAN)
156void MatchedPropertiesCache::sweep(Timer<MatchedPropertiesCache>*)
157{
158    // Look for cache entries containing a style declaration with a single ref and remove them.
159    // This may happen when an element attribute mutation causes it to generate a new inlineStyle()
160    // or presentationAttributeStyle(), potentially leaving this cache with the last ref on the old one.
161    Vector<unsigned, 16> toRemove;
162    Cache::iterator it = m_cache.begin();
163    Cache::iterator end = m_cache.end();
164    for (; it != end; ++it) {
165        CachedMatchedProperties* cacheItem = it->value.get();
166        Vector<MatchedProperties>& matchedProperties = cacheItem->matchedProperties;
167        for (size_t i = 0; i < matchedProperties.size(); ++i) {
168            if (matchedProperties[i].properties->hasOneRef()) {
169                toRemove.append(it->key);
170                break;
171            }
172        }
173    }
174    m_cache.removeAll(toRemove);
175    m_additionsSinceLastSweep = 0;
176}
177#endif
178
179bool MatchedPropertiesCache::isCacheable(const Element* element, const RenderStyle* style, const RenderStyle* parentStyle)
180{
181    // FIXME: CSSPropertyWebkitWritingMode modifies state when applying to document element. We can't skip the applying by caching.
182    if (element == element->document().documentElement() && element->document().writingModeSetOnDocumentElement())
183        return false;
184    if (style->unique() || (style->styleType() != NOPSEUDO && parentStyle->unique()))
185        return false;
186    if (style->hasAppearance())
187        return false;
188    if (style->zoom() != RenderStyle::initialZoom())
189        return false;
190    if (style->writingMode() != RenderStyle::initialWritingMode())
191        return false;
192    // The cache assumes static knowledge about which properties are inherited.
193    if (parentStyle->hasExplicitlyInheritedProperties())
194        return false;
195    return true;
196}
197
198void MatchedPropertiesCache::trace(Visitor* visitor)
199{
200#if ENABLE(OILPAN)
201    visitor->trace(m_cache);
202#endif
203}
204
205}
206