1 /* 2 * CSS Media Query Evaluator 3 * 4 * Copyright (C) 2006 Kimmo Kinnunen <kimmo.t.kinnunen@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 "PlatformString.h" 32 33 namespace WebCore { 34 class CSSStyleSelector; 35 class Frame; 36 class RenderStyle; 37 class MediaList; 38 class MediaQueryExp; 39 40 /** 41 * Class that evaluates css media queries as defined in 42 * CSS3 Module "Media Queries" (http://www.w3.org/TR/css3-mediaqueries/) 43 * Special constructors are needed, if simple media queries are to be 44 * evaluated without knowledge of the medium features. This can happen 45 * for example when parsing UA stylesheets, if evaluation is done 46 * right after parsing. 47 * 48 * the boolean parameter is used to approximate results of evaluation, if 49 * the device characteristics are not known. This can be used to prune the loading 50 * of stylesheets to only those which are probable to match. 51 */ 52 class MediaQueryEvaluator { 53 WTF_MAKE_NONCOPYABLE(MediaQueryEvaluator); WTF_MAKE_FAST_ALLOCATED; 54 public: 55 /** Creates evaluator which evaluates only simple media queries 56 * Evaluator returns true for "all", and returns value of \mediaFeatureResult 57 * for any media features 58 */ 59 MediaQueryEvaluator(bool mediaFeatureResult = false); 60 61 /** Creates evaluator which evaluates only simple media queries 62 * Evaluator returns true for acceptedMediaType and returns value of \mediafeatureResult 63 * for any media features 64 */ 65 MediaQueryEvaluator(const String& acceptedMediaType, bool mediaFeatureResult = false); 66 MediaQueryEvaluator(const char* acceptedMediaType, bool mediaFeatureResult = false); 67 68 /** Creates evaluator which evaluates full media queries 69 */ 70 MediaQueryEvaluator(const String& acceptedMediaType, Frame*, RenderStyle*); 71 72 ~MediaQueryEvaluator(); 73 74 bool mediaTypeMatch(const String& mediaTypeToMatch) const; 75 bool mediaTypeMatchSpecific(const char* mediaTypeToMatch) const; 76 77 /** Evaluates a list of media queries */ 78 bool eval(const MediaList*, CSSStyleSelector* = 0) const; 79 80 /** Evaluates media query subexpression, ie "and (media-feature: value)" part */ 81 bool eval(const MediaQueryExp*) const; 82 83 private: 84 String m_mediaType; 85 Frame* m_frame; // not owned 86 RefPtr<RenderStyle> m_style; 87 bool m_expResult; 88 }; 89 90 } // namespace 91 #endif 92