A thread-safe Media Query Parser

Source/core/css/parser/MediaQueryParser.h

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef MediaQueryParser_h
+#define MediaQueryParser_h
+
+#include "core/css/CSSParserValues.h"
+#include "core/css/MediaList.h"
+#include "core/css/MediaQuery.h"
+#include "core/css/MediaQueryExp.h"
+#include "core/css/parser/MediaQueryToken.h"
+#include "wtf/Vector.h"
+#include "wtf/text/WTFString.h"
+
+namespace WebCore {
+
+class MediaQuerySet;
+
+class MediaQueryData {
+private:
+    MediaQuery::Restrictor m_restrictor;
+    String m_mediaType;
+    OwnPtr<ExpressionHeapVector> m_expressions;
+    String m_mediaFeature;
+    CSSParserValueList m_valueList;
+    bool m_mediaTypeSet;
+
+public:
+    MediaQueryData();
+    void resetCurrentQuery();
+    bool addExpression();
+    void addParserValue(MediaQueryTokenType, MediaQueryToken&);
+    void setMediaType(const String&);
+    PassOwnPtr<MediaQuery> takeMediaQueryAndClear();
+
+    inline bool currentMediaQueryChanged() const
+    {
+        return (m_restrictor != MediaQuery::None || m_mediaTypeSet || m_expressions->size() > 0);
+    }
+
+    inline void setRestrictor(MediaQuery::Restrictor restrictor) { m_restrictor = restrictor; }
+
+    inline void setMediaFeature(const String& str) { m_mediaFeature = str; }
+};
+
+class MediaQueryParser {
+public:
+    static PassRefPtrWillBeRawPtr<MediaQuerySet> parse(const String&);
+
+private:
+    MediaQueryParser(const String&);
+    virtual ~MediaQueryParser() { };
+
+    PassRefPtrWillBeRawPtr<MediaQuerySet> parseImpl();
+
+    typedef Vector<MediaQueryToken>::iterator TokenIterator;
+
+    void processToken(TokenIterator&);
+
+    void readRestrictor(MediaQueryTokenType, TokenIterator&);
+    void readMediaType(MediaQueryTokenType, TokenIterator&);
+    void readAnd(MediaQueryTokenType, TokenIterator&);
+    void readFeatureStart(MediaQueryTokenType, TokenIterator&);
+    void readFeature(MediaQueryTokenType, TokenIterator&);
+    void readFeatureColon(MediaQueryTokenType, TokenIterator&);
+    void readFeatureValue(MediaQueryTokenType, TokenIterator&);
+    void readFeatureEnd(MediaQueryTokenType, TokenIterator&);
+    void skipUntilComma(MediaQueryTokenType, TokenIterator&);
+    void skipUntilParenthesis(MediaQueryTokenType, TokenIterator&);
+    void done(MediaQueryTokenType, TokenIterator&);
+
+    typedef void (MediaQueryParser::*State)(MediaQueryTokenType, TokenIterator&);
+
+    void setStateAndRestrict(State, MediaQuery::Restrictor);
+
+    const State ReadRestrictor = &MediaQueryParser::readRestrictor;
+    const State ReadMediaType = &MediaQueryParser::readMediaType;
+    const State ReadAnd = &MediaQueryParser::readAnd;
+    const State ReadFeatureStart = &MediaQueryParser::readFeatureStart;
+    const State ReadFeature = &MediaQueryParser::readFeature;
+    const State ReadFeatureColon = &MediaQueryParser::readFeatureColon;
+    const State ReadFeatureValue = &MediaQueryParser::readFeatureValue;
+    const State ReadFeatureEnd = &MediaQueryParser::readFeatureEnd;
+    const State SkipUntilComma = &MediaQueryParser::skipUntilComma;
+    const State SkipUntilParenthesis = &MediaQueryParser::skipUntilParenthesis;
+    const State Done = &MediaQueryParser::done;
+
+    State m_state;
+    Vector<MediaQueryToken> m_tokens;
+    MediaQueryData m_mediaQueryData;
+    RefPtrWillBeMember<MediaQuerySet> m_querySet;
+};
+
+} // namespace WebCore
+
+#endif // MediaQueryParser_h