MediaQueryParser.cpp   [plain text]

// Copyright 2014 The Chromium Authors. All rights reserved.
// Copyright (C) 2016 Apple Inc. All rights reserved.
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#include "config.h"
#include "MediaQueryParser.h"

#include "CSSTokenizer.h"
#include "MediaList.h"
#include "MediaQueryParserContext.h"
#include <wtf/Vector.h>

namespace WebCore {

RefPtr<MediaQuerySet> MediaQueryParser::parseMediaQuerySet(const String& queryString, MediaQueryParserContext context)
{
    return parseMediaQuerySet(CSSTokenizer(queryString).tokenRange(), context);
}

RefPtr<MediaQuerySet> MediaQueryParser::parseMediaQuerySet(CSSParserTokenRange range, MediaQueryParserContext context)
{
    return MediaQueryParser(MediaQuerySetParser, context).parseInternal(range);
}

RefPtr<MediaQuerySet> MediaQueryParser::parseMediaCondition(CSSParserTokenRange range, MediaQueryParserContext context)
{
    return MediaQueryParser(MediaConditionParser, context).parseInternal(range);
}

const MediaQueryParser::State MediaQueryParser::ReadRestrictor = &MediaQueryParser::readRestrictor;
const MediaQueryParser::State MediaQueryParser::ReadMediaNot = &MediaQueryParser::readMediaNot;
const MediaQueryParser::State MediaQueryParser::ReadMediaType = &MediaQueryParser::readMediaType;
const MediaQueryParser::State MediaQueryParser::ReadAnd = &MediaQueryParser::readAnd;
const MediaQueryParser::State MediaQueryParser::ReadFeatureStart = &MediaQueryParser::readFeatureStart;
const MediaQueryParser::State MediaQueryParser::ReadFeature = &MediaQueryParser::readFeature;
const MediaQueryParser::State MediaQueryParser::ReadFeatureColon = &MediaQueryParser::readFeatureColon;
const MediaQueryParser::State MediaQueryParser::ReadFeatureValue = &MediaQueryParser::readFeatureValue;
const MediaQueryParser::State MediaQueryParser::ReadFeatureEnd = &MediaQueryParser::readFeatureEnd;
const MediaQueryParser::State MediaQueryParser::SkipUntilComma = &MediaQueryParser::skipUntilComma;
const MediaQueryParser::State MediaQueryParser::SkipUntilBlockEnd = &MediaQueryParser::skipUntilBlockEnd;
const MediaQueryParser::State MediaQueryParser::Done = &MediaQueryParser::done;

MediaQueryParser::MediaQueryParser(ParserType parserType, MediaQueryParserContext context)
    : m_parserType(parserType)
    , m_mediaQueryData(context)
    , m_querySet(MediaQuerySet::create())
    
{
    if (parserType == MediaQuerySetParser)
        m_state = &MediaQueryParser::readRestrictor;
    else // MediaConditionParser
        m_state = &MediaQueryParser::readMediaNot;
}

MediaQueryParser::~MediaQueryParser() = default;

void MediaQueryParser::setStateAndRestrict(State state, MediaQuery::Restrictor restrictor)
{
    m_mediaQueryData.setRestrictor(restrictor);
    m_state = state;
}

// State machine member functions start here
void MediaQueryParser::readRestrictor(CSSParserTokenType type, const CSSParserToken& token, CSSParserTokenRange& range)
{
    readMediaType(type, token, range);
}

void MediaQueryParser::readMediaNot(CSSParserTokenType type, const CSSParserToken& token, CSSParserTokenRange& range)
{
    if (type == IdentToken && equalIgnoringASCIICase(token.value(), "not"))
        setStateAndRestrict(ReadFeatureStart, MediaQuery::Not);
    else
        readFeatureStart(type, token, range);
}

static bool isRestrictorOrLogicalOperator(const CSSParserToken& token)
{
    // FIXME: it would be more efficient to use lower-case always for tokenValue.
    return equalIgnoringASCIICase(token.value(), "not")
        || equalIgnoringASCIICase(token.value(), "and")
        || equalIgnoringASCIICase(token.value(), "or")
        || equalIgnoringASCIICase(token.value(), "only");
}

void MediaQueryParser::readMediaType(CSSParserTokenType type, const CSSParserToken& token, CSSParserTokenRange& range)
{
    if (type == LeftParenthesisToken) {
        if (m_mediaQueryData.restrictor() != MediaQuery::None)
            m_state = SkipUntilComma;
        else
            m_state = ReadFeature;
    } else if (type == IdentToken) {
        if (m_state == ReadRestrictor && equalIgnoringASCIICase(token.value(), "not"))
            setStateAndRestrict(ReadMediaType, MediaQuery::Not);
        else if (m_state == ReadRestrictor && equalIgnoringASCIICase(token.value(), "only"))
            setStateAndRestrict(ReadMediaType, MediaQuery::Only);
        else if (m_mediaQueryData.restrictor() != MediaQuery::None
            && isRestrictorOrLogicalOperator(token)) {
            m_state = SkipUntilComma;
        } else {
            m_mediaQueryData.setMediaType(token.value().toString());
            m_state = ReadAnd;
        }
    } else if (type == EOFToken && (!m_querySet->queryVector().size() || m_state != ReadRestrictor))
        m_state = Done;
    else {
        m_state = SkipUntilComma;
        if (type == CommaToken)
            skipUntilComma(type, token, range);
    }
}

void MediaQueryParser::commitMediaQuery()
{
    // FIXME-NEWPARSER: Convoluted and awful, but we can't change the MediaQuerySet yet because of the
    // old parser.
    static const NeverDestroyed<String> defaultMediaType { "all"_s };
    MediaQuery mediaQuery { m_mediaQueryData.restrictor(), m_mediaQueryData.mediaType().value_or(defaultMediaType), WTFMove(m_mediaQueryData.expressions()) };
    m_mediaQueryData.clear();
    m_querySet->addMediaQuery(WTFMove(mediaQuery));
}

void MediaQueryParser::readAnd(CSSParserTokenType type, const CSSParserToken& token, CSSParserTokenRange& /*range*/)
{
    if (type == IdentToken && equalIgnoringASCIICase(token.value(), "and")) {
        m_state = ReadFeatureStart;
    } else if (type == CommaToken && m_parserType != MediaConditionParser) {
        commitMediaQuery();
        m_state = ReadRestrictor;
    } else if (type == EOFToken)
        m_state = Done;
    else
        m_state = SkipUntilComma;
}

void MediaQueryParser::readFeatureStart(CSSParserTokenType type, const CSSParserToken& /*token*/, CSSParserTokenRange& /*range*/)
{
    if (type == LeftParenthesisToken)
        m_state = ReadFeature;
    else
        m_state = SkipUntilComma;
}

void MediaQueryParser::readFeature(CSSParserTokenType type, const CSSParserToken& token, CSSParserTokenRange& /*range*/)
{
    if (type == IdentToken) {
        m_mediaQueryData.setMediaFeature(token.value().toString());
        m_state = ReadFeatureColon;
    } else
        m_state = SkipUntilComma;
}

void MediaQueryParser::readFeatureColon(CSSParserTokenType type, const CSSParserToken& token, CSSParserTokenRange& range)
{
    if (type == ColonToken) {
        while (range.peek().type() == WhitespaceToken)
            range.consume();
        if (range.peek().type() == RightParenthesisToken || range.peek().type() == EOFToken)
            m_state = SkipUntilBlockEnd;
        else
            m_state = ReadFeatureValue;
    } else if (type == RightParenthesisToken || type == EOFToken) {
        m_mediaQueryData.addExpression(range);
        readFeatureEnd(type, token, range);
    } else
        m_state = SkipUntilBlockEnd;
}

void MediaQueryParser::readFeatureValue(CSSParserTokenType type, const CSSParserToken& token, CSSParserTokenRange& range)
{
    if (type == DimensionToken && token.unitType() == CSSPrimitiveValue::UnitType::CSS_UNKNOWN) {
        range.consume();
        m_state = SkipUntilComma;
    } else {
        m_mediaQueryData.addExpression(range);
        m_state = ReadFeatureEnd;
    }
}

void MediaQueryParser::readFeatureEnd(CSSParserTokenType type, const CSSParserToken& /*token*/, CSSParserTokenRange& /*range*/)
{
    if (type == RightParenthesisToken || type == EOFToken) {
        if (type != EOFToken && m_mediaQueryData.lastExpressionValid())
            m_state = ReadAnd;
        else
            m_state = SkipUntilComma;
    } else {
        m_mediaQueryData.removeLastExpression();
        m_state = SkipUntilBlockEnd;
    }
}

void MediaQueryParser::skipUntilComma(CSSParserTokenType type, const CSSParserToken& /*token*/, CSSParserTokenRange& /*range*/)
{
    if ((type == CommaToken && !m_blockWatcher.blockLevel()) || type == EOFToken) {
        m_state = ReadRestrictor;
        m_mediaQueryData.clear();
        MediaQuery query = MediaQuery(MediaQuery::Not, "all", Vector<MediaQueryExpression>());
        m_querySet->addMediaQuery(WTFMove(query));
    }
}

void MediaQueryParser::skipUntilBlockEnd(CSSParserTokenType /*type */, const CSSParserToken& token, CSSParserTokenRange& /*range*/)
{
    if (token.getBlockType() == CSSParserToken::BlockEnd && !m_blockWatcher.blockLevel())
        m_state = SkipUntilComma;
}

void MediaQueryParser::done(CSSParserTokenType /*type*/, const CSSParserToken& /*token*/, CSSParserTokenRange& /*range*/) { }

void MediaQueryParser::handleBlocks(const CSSParserToken& token)
{
    if (token.getBlockType() == CSSParserToken::BlockStart
        && (token.type() != LeftParenthesisToken || m_blockWatcher.blockLevel()))
            m_state = SkipUntilBlockEnd;
}

void MediaQueryParser::processToken(const CSSParserToken& token, CSSParserTokenRange& range)
{
    CSSParserTokenType type = token.type();

    if (m_state != ReadFeatureValue || type == WhitespaceToken) {
        handleBlocks(token);
        m_blockWatcher.handleToken(token);
        range.consume();
    }

    // Call the function that handles current state
    if (type != WhitespaceToken)
        ((this)->*(m_state))(type, token, range);
}

// The state machine loop
RefPtr<MediaQuerySet> MediaQueryParser::parseInternal(CSSParserTokenRange range)
{
    while (!range.atEnd())
        processToken(range.peek(), range);

    // FIXME: Can we get rid of this special case?
    if (m_parserType == MediaQuerySetParser)
        processToken(CSSParserToken(EOFToken), range);

    if (m_state != ReadAnd && m_state != ReadRestrictor && m_state != Done && m_state != ReadMediaNot) {
        MediaQuery query = MediaQuery(MediaQuery::Not, "all", Vector<MediaQueryExpression>());
        m_querySet->addMediaQuery(WTFMove(query));
    } else if (m_mediaQueryData.currentMediaQueryChanged())
        commitMediaQuery();

    m_querySet->shrinkToFit();

    return m_querySet;
}

MediaQueryParser::MediaQueryData::MediaQueryData(MediaQueryParserContext context)
    : m_context(context)
{
}

void MediaQueryParser::MediaQueryData::clear()
{
    m_restrictor = MediaQuery::None;
    m_mediaType = std::nullopt;
    m_mediaFeature = String();
    m_expressions.clear();
}

void MediaQueryParser::MediaQueryData::addExpression(CSSParserTokenRange& range)
{
    m_expressions.append(MediaQueryExpression { m_mediaFeature, range, m_context });
}

bool MediaQueryParser::MediaQueryData::lastExpressionValid()
{
    return m_expressions.last().isValid();
}

void MediaQueryParser::MediaQueryData::removeLastExpression()
{
    m_expressions.removeLast();
}

} // namespace WebCore