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      1 /*
      2  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
      3  *
      4  *  This library is free software; you can redistribute it and/or
      5  *  modify it under the terms of the GNU Library General Public
      6  *  License as published by the Free Software Foundation; either
      7  *  version 2 of the License, or (at your option) any later version.
      8  *
      9  *  This library is distributed in the hope that it will be useful,
     10  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
     11  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     12  *  Library General Public License for more details.
     13  *
     14  *  You should have received a copy of the GNU Library General Public License
     15  *  along with this library; see the file COPYING.LIB.  If not, write to
     16  *  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
     17  *  Boston, MA 02110-1301, USA.
     18  */
     19 
     20 #ifndef MediaQueryList_h
     21 #define MediaQueryList_h
     22 
     23 #include <wtf/Forward.h>
     24 #include <wtf/RefCounted.h>
     25 #include <wtf/RefPtr.h>
     26 
     27 namespace WebCore {
     28 
     29 class MediaList;
     30 class MediaQueryListListener;
     31 class MediaQueryEvaluator;
     32 class MediaQueryMatcher;
     33 
     34 // MediaQueryList interface is specified at http://dev.w3.org/csswg/cssom-view/#the-mediaquerylist-interface
     35 // The objects of this class are returned by window.matchMedia. They may be used to
     36 // retrieve the current value of the given media query and to add/remove listeners that
     37 // will be called whenever the value of the query changes.
     38 
     39 class MediaQueryList : public RefCounted<MediaQueryList> {
     40 public:
     41     static PassRefPtr<MediaQueryList> create(PassRefPtr<MediaQueryMatcher>, PassRefPtr<MediaList>, bool);
     42     ~MediaQueryList();
     43 
     44     String media() const;
     45     bool matches();
     46 
     47     void addListener(PassRefPtr<MediaQueryListListener>);
     48     void removeListener(PassRefPtr<MediaQueryListListener>);
     49 
     50     void evaluate(MediaQueryEvaluator*, bool& notificationNeeded);
     51 
     52 private:
     53     MediaQueryList(PassRefPtr<MediaQueryMatcher>, PassRefPtr<MediaList>, bool matches);
     54     void setMatches(bool);
     55 
     56     RefPtr<MediaQueryMatcher> m_matcher;
     57     RefPtr<MediaList> m_media;
     58     unsigned m_evaluationRound; // Indicates if the query has been evaluated after the last style selector change.
     59     unsigned m_changeRound; // Used to know if the query has changed in the last style selector change.
     60     bool m_matches;
     61 };
     62 
     63 }
     64 
     65 #endif // MediaQueryList_h
     66