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/**
* Copyright (C) 2023 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 INC. AND ITS CONTRIBUTORS ``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 INC. OR ITS 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 "config.h"
#include "ImmutableStyleProperties.h"
#include "CSSCustomPropertyValue.h"
#include "StylePropertiesInlines.h"
#include <wtf/HashMap.h>
#include <wtf/Hasher.h>
#include <wtf/IndexedRange.h>
#include <wtf/NeverDestroyed.h>
namespace WebCore {
DEFINE_ALLOCATOR_WITH_HEAP_IDENTIFIER(ImmutableStyleProperties);
ImmutableStyleProperties::ImmutableStyleProperties(std::span<const CSSProperty> properties, CSSParserMode mode)
: StyleProperties(mode, properties.size())
{
WTF_ALLOW_UNSAFE_BUFFER_USAGE_BEGIN
auto* metadataArray = const_cast<StylePropertyMetadata*>(this->metadataArray());
auto* valueArray = std::bit_cast<PackedPtr<CSSValue>*>(this->valueArray());
for (auto [i, property] : indexedRange(properties)) {
metadataArray[i] = property.metadata();
RefPtr value = property.value();
valueArray[i] = value.get();
value->ref();
}
WTF_ALLOW_UNSAFE_BUFFER_USAGE_END
}
ImmutableStyleProperties::~ImmutableStyleProperties()
{
WTF_ALLOW_UNSAFE_BUFFER_USAGE_BEGIN
auto* valueArray = std::bit_cast<PackedPtr<CSSValue>*>(this->valueArray());
for (unsigned i = 0; i < m_arraySize; ++i)
valueArray[i]->deref();
WTF_ALLOW_UNSAFE_BUFFER_USAGE_END
}
Ref<ImmutableStyleProperties> ImmutableStyleProperties::create(std::span<const CSSProperty> properties, CSSParserMode mode)
{
void* slot = ImmutableStylePropertiesMalloc::malloc(objectSize(properties.size()));
return adoptRef(*new (NotNull, slot) ImmutableStyleProperties(properties, mode));
}
static auto& deduplicationMap()
{
static NeverDestroyed<UncheckedKeyHashMap<unsigned, Ref<ImmutableStyleProperties>, AlreadyHashed>> map;
return map.get();
}
Ref<ImmutableStyleProperties> ImmutableStyleProperties::createDeduplicating(std::span<const CSSProperty> properties, CSSParserMode mode)
{
static constexpr auto maximumDeduplicationMapSize = 1024u;
if (deduplicationMap().size() >= maximumDeduplicationMapSize)
deduplicationMap().remove(deduplicationMap().random());
auto computeHash = [&] {
Hasher hasher;
add(hasher, mode);
for (auto& property : properties) {
if (!property.value()->addHash(hasher))
return 0u;
add(hasher, property.id(), property.isImportant());
}
return hasher.hash();
};
auto hash = computeHash();
if (!hash)
return create(properties, mode);
auto result = deduplicationMap().ensure(hash, [&] {
return create(properties, mode);
});
auto isEqual = [&](auto& existingValue) {
if (existingValue.propertyCount() != properties.size())
return false;
if (existingValue.cssParserMode() != mode)
return false;
for (auto [i, property] : indexedRange(properties)) {
if (existingValue.propertyAt(i).toCSSProperty() != property)
return false;
}
return true;
};
if (!result.isNewEntry && !isEqual(result.iterator->value.get()))
return create(properties, mode);
return result.iterator->value;
}
void ImmutableStyleProperties::clearDeduplicationMap()
{
deduplicationMap().clear();
}
int ImmutableStyleProperties::findPropertyIndex(CSSPropertyID propertyID) const
{
// Convert here propertyID into an uint16_t to compare it with the metadata's m_propertyID to avoid
// the compiler converting it to an int multiple times in the loop.
uint16_t id = enumToUnderlyingType(propertyID);
for (int n = m_arraySize - 1 ; n >= 0; --n) {
WTF_ALLOW_UNSAFE_BUFFER_USAGE_BEGIN
if (metadataArray()[n].m_propertyID == id)
return n;
WTF_ALLOW_UNSAFE_BUFFER_USAGE_END
}
return -1;
}
int ImmutableStyleProperties::findCustomPropertyIndex(StringView propertyName) const
{
for (int n = m_arraySize - 1 ; n >= 0; --n) {
WTF_ALLOW_UNSAFE_BUFFER_USAGE_BEGIN
if (metadataArray()[n].m_propertyID == CSSPropertyCustom) {
// We found a custom property. See if the name matches.
auto* value = valueArray()[n].get();
if (!value)
continue;
if (downcast<CSSCustomPropertyValue>(*value).name() == propertyName)
return n;
}
WTF_ALLOW_UNSAFE_BUFFER_USAGE_END
}
return -1;
}
}
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