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 MediaQueryMatcher_h 21 #define MediaQueryMatcher_h 22 23 #include "platform/heap/Handle.h" 24 #include "wtf/Forward.h" 25 #include "wtf/RefCounted.h" 26 #include "wtf/Vector.h" 27 28 namespace WebCore { 29 30 class Document; 31 class MediaQueryList; 32 class MediaQueryListListener; 33 class MediaQueryEvaluator; 34 class MediaQuerySet; 35 36 // MediaQueryMatcher class is responsible for keeping a vector of pairs 37 // MediaQueryList x MediaQueryListListener. It is responsible for evaluating the queries 38 // whenever it is needed and to call the listeners if the corresponding query has changed. 39 // The listeners must be called in the very same order in which they have been added. 40 41 class MediaQueryMatcher FINAL : public RefCountedWillBeGarbageCollected<MediaQueryMatcher> { 42 DECLARE_EMPTY_DESTRUCTOR_WILL_BE_REMOVED(MediaQueryMatcher); 43 public: create(Document * document)44 static PassRefPtrWillBeRawPtr<MediaQueryMatcher> create(Document* document) { return adoptRefWillBeNoop(new MediaQueryMatcher(document)); } 45 void documentDestroyed(); 46 47 void addListener(PassRefPtrWillBeRawPtr<MediaQueryListListener>, PassRefPtrWillBeRawPtr<MediaQueryList>); 48 void removeListener(MediaQueryListListener*, MediaQueryList*); 49 50 PassRefPtrWillBeRawPtr<MediaQueryList> matchMedia(const String&); 51 evaluationRound()52 unsigned evaluationRound() const { return m_evaluationRound; } 53 void styleResolverChanged(); 54 bool evaluate(const MediaQuerySet*); 55 56 void trace(Visitor*); 57 58 private: 59 class Listener FINAL : public NoBaseWillBeGarbageCollected<Listener> { 60 public: 61 Listener(PassRefPtrWillBeRawPtr<MediaQueryListListener>, PassRefPtrWillBeRawPtr<MediaQueryList>); 62 void evaluate(MediaQueryEvaluator*); 63 listener()64 MediaQueryListListener* listener() { return m_listener.get(); } query()65 MediaQueryList* query() { return m_query.get(); } 66 67 void trace(Visitor*); 68 69 private: 70 RefPtrWillBeMember<MediaQueryListListener> m_listener; 71 RefPtrWillBeMember<MediaQueryList> m_query; 72 }; 73 74 MediaQueryMatcher(Document*); 75 PassOwnPtr<MediaQueryEvaluator> prepareEvaluator() const; 76 AtomicString mediaType() const; 77 78 RawPtrWillBeMember<Document> m_document; 79 WillBeHeapVector<OwnPtrWillBeMember<Listener> > m_listeners; 80 81 // This value is incremented at style selector changes. 82 // It is used to avoid evaluating queries more then once and to make sure 83 // that a media query result change is notified exactly once. 84 unsigned m_evaluationRound; 85 }; 86 87 } 88 89 #endif // MediaQueryMatcher_h 90