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 <wtf/text/WTFString.h>
32
33namespace WebCore {
34class Frame;
35class MediaQueryExp;
36class MediaQuerySet;
37class RenderStyle;
38class StyleResolver;
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 */
52class MediaQueryEvaluator {
53     WTF_MAKE_NONCOPYABLE(MediaQueryEvaluator); WTF_MAKE_FAST_ALLOCATED;
54public:
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    explicit 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 MediaQuerySet*, StyleResolver* = 0) const;
79
80    /** Evaluates media query subexpression, ie "and (media-feature: value)" part */
81    bool eval(const MediaQueryExp*) const;
82
83private:
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