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/*
* 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 "base/macros.h"
#include "core/CoreExport.h"
#include "platform/heap/Handle.h"
#include "platform/wtf/text/WTFString.h"
namespace blink {
class LocalFrame;
class MediaQuery;
class MediaQueryExp;
class MediaQueryResult;
class MediaQuerySet;
class MediaValues;
class MediaValuesInitialViewport;
using MediaQueryResultList = Vector<MediaQueryResult>;
// 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 CORE_EXPORT MediaQueryEvaluator final
: public GarbageCollectedFinalized<MediaQueryEvaluator> {
public:
static void Init();
// Creates evaluator which evaluates to true for all media queries.
MediaQueryEvaluator() = default;
// Creates evaluator which evaluates only simple media queries
// Evaluator returns true for acceptedMediaType and returns true for any media
// features.
MediaQueryEvaluator(const char* accepted_media_type);
// 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&);
explicit MediaQueryEvaluator(MediaValuesInitialViewport*);
~MediaQueryEvaluator();
bool MediaTypeMatch(const String& media_type_to_match) const;
// Evaluates a list of media queries.
bool Eval(const MediaQuerySet&,
MediaQueryResultList* viewport_dependent = nullptr,
MediaQueryResultList* device_dependent = nullptr) const;
// Evaluates media query.
bool Eval(const MediaQuery&,
MediaQueryResultList* viewport_dependent = nullptr,
MediaQueryResultList* device_dependent = nullptr) const;
// Evaluates media query subexpression, ie "and (media-feature: value)" part.
bool Eval(const MediaQueryExp&) const;
void Trace(blink::Visitor*);
private:
const String MediaType() const;
String media_type_;
Member<MediaValues> media_values_;
DISALLOW_COPY_AND_ASSIGN(MediaQueryEvaluator);
};
} // namespace blink
#endif