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/*
* Copyright (C) 1999 Lars Knoll (knoll@kde.org)
* Copyright (C) 2004-2005 Allan Sandfeld Jensen (kde@carewolf.com)
* Copyright (C) 2006, 2007 Nicholas Shanks (webkit@nickshanks.com)
* Copyright (C) 2005-2019 Apple Inc. All rights reserved.
* Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
* Copyright (C) 2007, 2008 Eric Seidel <eric@webkit.org>
* Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
* Copyright (c) 2011, Code Aurora Forum. All rights reserved.
* Copyright (C) Research In Motion Limited 2011. All rights reserved.
* Copyright (C) 2012, 2013 Google Inc. All rights reserved.
* Copyright (C) 2014 Igalia S.L.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public License
* along with this library; see the file COPYING.LIB. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
#include "config.h"
#include "MatchedDeclarationsCache.h"
#include "CSSFontSelector.h"
#include "Document.h"
#include "FontCascade.h"
#include "RenderStyleInlines.h"
#include "StyleResolver.h"
#include <wtf/text/StringHash.h>
namespace WebCore {
namespace Style {
MatchedDeclarationsCache::MatchedDeclarationsCache(const Resolver& owner)
: m_owner(owner)
, m_sweepTimer(*this, &MatchedDeclarationsCache::sweep)
{
}
MatchedDeclarationsCache::~MatchedDeclarationsCache() = default;
void MatchedDeclarationsCache::ref() const
{
m_owner->ref();
}
void MatchedDeclarationsCache::deref() const
{
m_owner->deref();
}
bool MatchedDeclarationsCache::isCacheable(const Element& element, const RenderStyle& style, const RenderStyle& parentStyle)
{
// FIXME: Writing mode and direction properties modify state when applying to document element by calling
// Document::setWritingMode/DirectionSetOnDocumentElement. We can't skip the applying by caching.
if (&element == element.document().documentElement())
return false;
// content:attr() value depends on the element it is being applied to.
if (style.hasAttrContent() || (style.styleType() != PseudoId::None && parentStyle.hasAttrContent()))
return false;
if (style.zoom() != RenderStyle::initialZoom())
return false;
if (style.writingMode() != RenderStyle::initialWritingMode() || style.direction() != RenderStyle::initialDirection())
return false;
// The cache assumes static knowledge about which properties are inherited.
if (style.hasExplicitlyInheritedProperties())
return false;
if (style.usesContainerUnits())
return false;
// Getting computed style after a font environment change but before full style resolution may involve styles with non-current fonts.
// Avoid caching them.
auto& fontSelector = element.document().fontSelector();
if (!style.fontCascade().isCurrent(fontSelector))
return false;
if (!parentStyle.fontCascade().isCurrent(fontSelector))
return false;
// FIXME: counter-style: we might need to resolve cache like for fontSelector here (rdar://103018993).
return true;
}
bool MatchedDeclarationsCache::Entry::isUsableAfterHighPriorityProperties(const RenderStyle& style) const
{
if (style.effectiveZoom() != renderStyle->effectiveZoom())
return false;
#if ENABLE(DARK_MODE_CSS)
if (style.colorScheme() != renderStyle->colorScheme())
return false;
#endif
return CSSPrimitiveValue::equalForLengthResolution(style, *renderStyle);
}
unsigned MatchedDeclarationsCache::computeHash(const MatchResult& matchResult)
{
if (!matchResult.isCacheable)
return 0;
return WTF::computeHash(matchResult);
}
const MatchedDeclarationsCache::Entry* MatchedDeclarationsCache::find(unsigned hash, const MatchResult& matchResult)
{
if (!hash)
return nullptr;
auto it = m_entries.find(hash);
if (it == m_entries.end())
return nullptr;
auto& entry = it->value;
if (matchResult != entry.matchResult)
return nullptr;
return &entry;
}
void MatchedDeclarationsCache::add(const RenderStyle& style, const RenderStyle& parentStyle, const RenderStyle* userAgentAppearanceStyle, unsigned hash, const MatchResult& matchResult)
{
constexpr unsigned additionsBetweenSweeps = 100;
if (++m_additionsSinceLastSweep >= additionsBetweenSweeps && !m_sweepTimer.isActive()) {
constexpr auto sweepDelay = 1_min;
m_sweepTimer.startOneShot(sweepDelay);
}
auto userAgentAppearanceStyleCopy = [&]() -> std::unique_ptr<RenderStyle> {
if (userAgentAppearanceStyle)
return RenderStyle::clonePtr(*userAgentAppearanceStyle);
return { };
};
ASSERT(hash);
// Note that we don't cache the original RenderStyle instance. It may be further modified.
// The RenderStyle in the cache is really just a holder for the substructures and never used as-is.
m_entries.add(hash, Entry { matchResult, RenderStyle::clonePtr(style), RenderStyle::clonePtr(parentStyle), userAgentAppearanceStyleCopy() });
}
void MatchedDeclarationsCache::remove(unsigned hash)
{
m_entries.remove(hash);
}
void MatchedDeclarationsCache::invalidate()
{
m_entries.clear();
}
void MatchedDeclarationsCache::clearEntriesAffectedByViewportUnits()
{
Ref protectedThis { *this };
m_entries.removeIf([](auto& keyValue) {
return keyValue.value.renderStyle->usesViewportUnits();
});
}
void MatchedDeclarationsCache::sweep()
{
Ref protectedThis { *this };
// Look for cache entries containing a style declaration with a single ref and remove them.
// This may happen when an element attribute mutation causes it to generate a new inlineStyle()
// or presentationalHintStyle(), potentially leaving this cache with the last ref on the old one.
auto hasOneRef = [](auto& declarations) {
for (auto& matchedProperties : declarations) {
if (matchedProperties.properties->hasOneRef())
return true;
}
return false;
};
m_entries.removeIf([&](auto& keyValue) {
auto& matchResult = keyValue.value.matchResult;
return hasOneRef(matchResult.userAgentDeclarations) || hasOneRef(matchResult.userDeclarations) || hasOneRef(matchResult.authorDeclarations);
});
m_additionsSinceLastSweep = 0;
}
}
}
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