/*
 * CSS Media Query Evaluator
 *
 * Copyright (C) 2006 Kimmo Kinnunen <kimmo.t.kinnunen@nokia.com>.
 *
 * 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 THE AUTHOR ``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 COMPUTER, INC. OR
 * 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.
 */

#ifndef SKY_ENGINE_CORE_CSS_MEDIAQUERYEVALUATOR_H_
#define SKY_ENGINE_CORE_CSS_MEDIAQUERYEVALUATOR_H_

#include "sky/engine/platform/heap/Handle.h"
#include "sky/engine/wtf/text/WTFString.h"

namespace blink {
class LocalFrame;
class MediaQuery;
class MediaQueryExp;
class MediaQuerySet;
class MediaValues;
class RenderStyle;

// Class that evaluates css media queries as defined in
// CSS3 Module "Media Queries" (http://www.w3.org/TR/css3-mediaqueries/)
// Special constructors are needed, if simple media queries are to be
// evaluated without knowledge of the medium features. This can happen
// for example when parsing UA stylesheets, if evaluation is done
// right after parsing.
//
// the boolean parameter is used to approximate results of evaluation, if
// the device characteristics are not known. This can be used to prune the loading
// of stylesheets to only those which are probable to match.

class MediaQueryEvaluator {
    WTF_MAKE_NONCOPYABLE(MediaQueryEvaluator); WTF_MAKE_FAST_ALLOCATED;
public:
    // Creates evaluator which evaluates only simple media queries
    // Evaluator returns true for "all", and returns value of \mediaFeatureResult
    // for any media features.

    explicit MediaQueryEvaluator(bool mediaFeatureResult = false);

    // Creates evaluator which evaluates only simple media queries
    // Evaluator  returns true for acceptedMediaType and returns value of \mediafeatureResult
    // for any media features.

    MediaQueryEvaluator(const char* acceptedMediaType, bool mediaFeatureResult = false);

    // Creates evaluator which evaluates full media queries.
    explicit MediaQueryEvaluator(LocalFrame*);

    // Creates evaluator which evaluates in a thread-safe manner a subset of media values.
    explicit MediaQueryEvaluator(const MediaValues&);

    ~MediaQueryEvaluator();

    bool mediaTypeMatch(const String& mediaTypeToMatch) const;

    // Evaluates a list of media queries.
    bool eval(const MediaQuerySet*) const;

    // Evaluates media query.
    bool eval(const MediaQuery*) const;

    // Evaluates media query subexpression, ie "and (media-feature: value)" part.
    bool eval(const MediaQueryExp*) const;

private:
    const String mediaType() const;

    String m_mediaType;
    bool m_expectedResult;
    RefPtr<MediaValues> m_mediaValues;
};

} // namespace
#endif  // SKY_ENGINE_CORE_CSS_MEDIAQUERYEVALUATOR_H_