/*

 * 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 MediaQueryEvaluator_h

#define MediaQueryEvaluator_h

#include "PlatformString.h"

namespace WebCore {

class CSSStyleSelector;

class Frame;

class RenderStyle;

class MediaList;

class MediaQueryExp;

/**

 * 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 {

public:

    /** Creates evaluator which evaluates only simple media queries

     *  Evaluator returns true for "all", and returns value of \mediaFeatureResult

     *  for any media features

     */

    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 String& acceptedMediaType, bool mediaFeatureResult = false);

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

    /** Creates evaluator which evaluates full media queries

     */

    MediaQueryEvaluator(const String& acceptedMediaType, Frame*, RenderStyle*);

    ~MediaQueryEvaluator();

    bool mediaTypeMatch(const String& mediaTypeToMatch) const;

    bool mediaTypeMatchSpecific(const char* mediaTypeToMatch) const;

    /** Evaluates a list of media queries */

    bool eval(const MediaList*, CSSStyleSelector* = 0) const;

    /** Evaluates media query subexpression, ie "and (media-feature: value)" part */

    bool eval(const MediaQueryExp*) const;

private:

    String m_mediaType;

    Frame* m_frame; // not owned

    RenderStyle* m_style; // not owned

    bool m_expResult;

};

} // namespace

#endif