1 /* 2 * CSS Media Query Evaluator 3 * 4 * Copyright (C) 2006 Kimmo Kinnunen <kimmo.t.kinnunen (at) nokia.com>. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY 16 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 18 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE COMPUTER, INC. OR 19 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 20 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 22 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY 23 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 25 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28 #ifndef MediaQueryEvaluator_h 29 #define MediaQueryEvaluator_h 30 31 #include "platform/heap/Handle.h" 32 #include "wtf/text/WTFString.h" 33 34 namespace blink { 35 class LocalFrame; 36 class MediaQuery; 37 class MediaQueryExp; 38 class MediaQueryResult; 39 class MediaQuerySet; 40 class MediaValues; 41 42 typedef WillBeHeapVector<RefPtrWillBeMember<MediaQueryResult> > MediaQueryResultList; 43 44 // Class that evaluates css media queries as defined in 45 // CSS3 Module "Media Queries" (http://www.w3.org/TR/css3-mediaqueries/) 46 // Special constructors are needed, if simple media queries are to be 47 // evaluated without knowledge of the medium features. This can happen 48 // for example when parsing UA stylesheets, if evaluation is done 49 // right after parsing. 50 // 51 // the boolean parameter is used to approximate results of evaluation, if 52 // the device characteristics are not known. This can be used to prune the loading 53 // of stylesheets to only those which are probable to match. 54 55 class MediaQueryEvaluator { 56 WTF_MAKE_NONCOPYABLE(MediaQueryEvaluator); WTF_MAKE_FAST_ALLOCATED; 57 public: 58 // Creates evaluator which evaluates only simple media queries 59 // Evaluator returns true for "all", and returns value of \mediaFeatureResult 60 // for any media features. 61 62 explicit MediaQueryEvaluator(bool mediaFeatureResult = false); 63 64 // Creates evaluator which evaluates only simple media queries 65 // Evaluator returns true for acceptedMediaType and returns value of \mediafeatureResult 66 // for any media features. 67 68 MediaQueryEvaluator(const char* acceptedMediaType, bool mediaFeatureResult = false); 69 70 // Creates evaluator which evaluates full media queries. 71 explicit MediaQueryEvaluator(LocalFrame*); 72 73 // Creates evaluator which evaluates in a thread-safe manner a subset of media values. 74 explicit MediaQueryEvaluator(const MediaValues&); 75 76 ~MediaQueryEvaluator(); 77 78 bool mediaTypeMatch(const String& mediaTypeToMatch) const; 79 80 // Evaluates a list of media queries. 81 bool eval(const MediaQuerySet*, MediaQueryResultList* = 0) const; 82 83 // Evaluates media query. 84 bool eval(const MediaQuery*, MediaQueryResultList*) const; 85 86 // Evaluates media query subexpression, ie "and (media-feature: value)" part. 87 bool eval(const MediaQueryExp*) const; 88 89 private: 90 const String mediaType() const; 91 92 String m_mediaType; 93 bool m_expectedResult; 94 RefPtr<MediaValues> m_mediaValues; 95 }; 96 97 } // namespace 98 #endif 99
