Source/WebCore/css/CSSSubstitutionValue.cpp

// Copyright 2015 The Chromium Authors. All rights reserved.
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#include "config.h"
#include "CSSSubstitutionValue.h"

#include "CSSSubstitutionParser.h"
#include "CSSVariableData.h"

namespace WebCore {

// The tokens are flat, including nested ones, and functionId() is CSSValueInvalid for anything that
// is not a function token, so a linear scan finds inherit() at any depth.
static bool containsInheritFunctionToken(const CSSVariableData& data)
{
    if (!data.context().cssInheritFunctionEnabled)
        return false;
    for (auto& token : data.tokens()) {
        if (token.functionId() == CSSValueInherit)
            return true;
    }
    return false;
}

CSSSubstitutionValue::CSSSubstitutionValue(Ref<CSSVariableData>&& data, const CSSNamespacePrefixMap& namespacePrefixMap)
    : CSSValue(ClassType::Substitution)
    , m_data(WTF::move(data))
    , m_namespacePrefixMap(namespacePrefixMap)
    , m_containsInheritFunction(containsInheritFunctionToken(m_data))
{
    cacheSimpleReference();
}

Ref<CSSSubstitutionValue> CSSSubstitutionValue::create(const CSSParserTokenRange& range, const CSSNamespacePrefixMap& namespacePrefixMap, const CSSParserContext& context)
{
    return adoptRef(*new CSSSubstitutionValue(CSSVariableData::create(range, context), namespacePrefixMap));
}

Ref<CSSSubstitutionValue> CSSSubstitutionValue::create(Ref<CSSVariableData>&& data)
{
    return adoptRef(*new CSSSubstitutionValue(WTF::move(data), CSSNamespacePrefixMap { }));
}

bool CSSSubstitutionValue::equals(const CSSSubstitutionValue& other) const
{
    return arePointingToEqualData(m_data, other.m_data);
}

String CSSSubstitutionValue::customCSSText(const CSS::SerializationContext&) const
{
    if (m_stringValue.isNull())
        m_stringValue = m_data->serialize();
    return m_stringValue;
}

const CSSParserContext& CSSSubstitutionValue::context() const
{
    return m_data->context();
}

void CSSSubstitutionValue::cacheSimpleReference()
{
    ASSERT(!m_simpleReference);

    auto range = m_data->tokenRange();

    auto functionId = range.peek().functionId();

    if (functionId == CSSValueInternalAutoBase) {
        range.consumeBlock();
        if (range.atEnd())
            m_simpleReference = SimpleReference { { }, CSSValueInternalAutoBase };
        return;
    }

    if (functionId != CSSValueVar && functionId != CSSValueEnv)
        return;

    auto variableRange = range.consumeBlock();
    if (!range.atEnd())
        return;

    variableRange.consumeWhitespace();

    // var() names a <custom-property-name> and env() an <ident>. Anything else takes the full
    // substitution path, since var()'s name argument may be any <declaration-value>.
    auto& nameToken = variableRange.consumeIncludingWhitespace();
    if (nameToken.type() != IdentToken)
        return;
    if (functionId == CSSValueVar && !CSSSubstitutionParser::isValidCustomPropertyName(nameToken))
        return;

    // No fallback support on this path.
    if (!variableRange.atEnd())
        return;

    m_simpleReference = SimpleReference { nameToken.value().toAtomString(), functionId };
}

} // namespace WebCore