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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 #include "config.h"
     21 #include "MediaQueryMatcher.h"
     22 
     23 #include "CSSStyleSelector.h"
     24 #include "Document.h"
     25 #include "Element.h"
     26 #include "FrameView.h"
     27 #include "MediaList.h"
     28 #include "MediaQueryEvaluator.h"
     29 #include "MediaQueryList.h"
     30 #include "MediaQueryListListener.h"
     31 
     32 namespace WebCore {
     33 
     34 MediaQueryMatcher::Listener::Listener(PassRefPtr<MediaQueryListListener> listener, PassRefPtr<MediaQueryList> query)
     35     : m_listener(listener)
     36     , m_query(query)
     37 {
     38 }
     39 
     40 MediaQueryMatcher::Listener::~Listener()
     41 {
     42 }
     43 
     44 void MediaQueryMatcher::Listener::evaluate(ScriptState* state, MediaQueryEvaluator* evaluator)
     45 {
     46     bool notify;
     47     m_query->evaluate(evaluator, notify);
     48     if (notify)
     49         m_listener->queryChanged(state, m_query.get());
     50 }
     51 
     52 MediaQueryMatcher::MediaQueryMatcher(Document* document)
     53     : m_document(document)
     54     , m_evaluationRound(1)
     55 {
     56     ASSERT(m_document);
     57 }
     58 
     59 MediaQueryMatcher::~MediaQueryMatcher()
     60 {
     61 }
     62 
     63 void MediaQueryMatcher::documentDestroyed()
     64 {
     65     m_listeners.clear();
     66     m_document = 0;
     67 }
     68 
     69 String MediaQueryMatcher::mediaType() const
     70 {
     71     if (!m_document || !m_document->frame() || !m_document->frame()->view())
     72         return String();
     73 
     74     return m_document->frame()->view()->mediaType();
     75 }
     76 
     77 PassOwnPtr<MediaQueryEvaluator> MediaQueryMatcher::prepareEvaluator() const
     78 {
     79     if (!m_document || !m_document->frame())
     80         return 0;
     81 
     82     Element* documentElement = m_document->documentElement();
     83     if (!documentElement)
     84         return 0;
     85 
     86     CSSStyleSelector* styleSelector = m_document->styleSelector();
     87     if (!styleSelector)
     88         return 0;
     89 
     90     RefPtr<RenderStyle> rootStyle = styleSelector->styleForElement(documentElement, 0 /*defaultParent*/, false /*allowSharing*/, true /*resolveForRootDefault*/);
     91 
     92     return adoptPtr(new MediaQueryEvaluator(mediaType(), m_document->frame(), rootStyle.get()));
     93 }
     94 
     95 bool MediaQueryMatcher::evaluate(MediaList* media)
     96 {
     97     if (!media)
     98         return false;
     99 
    100     OwnPtr<MediaQueryEvaluator> evaluator(prepareEvaluator());
    101     return evaluator && evaluator->eval(media);
    102 }
    103 
    104 PassRefPtr<MediaQueryList> MediaQueryMatcher::matchMedia(const String& query)
    105 {
    106     if (!m_document)
    107         return 0;
    108 
    109     RefPtr<MediaList> media = MediaList::create(query, false);
    110     return MediaQueryList::create(this, media, evaluate(media.get()));
    111 }
    112 
    113 void MediaQueryMatcher::addListener(PassRefPtr<MediaQueryListListener> listener, PassRefPtr<MediaQueryList> query)
    114 {
    115     if (!m_document)
    116         return;
    117 
    118     for (size_t i = 0; i < m_listeners.size(); ++i) {
    119         if (*m_listeners[i]->listener() == *listener && m_listeners[i]->query() == query)
    120             return;
    121     }
    122 
    123     m_listeners.append(new Listener(listener, query));
    124 }
    125 
    126 void MediaQueryMatcher::removeListener(MediaQueryListListener* listener, MediaQueryList* query)
    127 {
    128     if (!m_document)
    129         return;
    130 
    131     for (size_t i = 0; i < m_listeners.size(); ++i) {
    132         if (*m_listeners[i]->listener() == *listener && m_listeners[i]->query() == query) {
    133             m_listeners.remove(i);
    134             return;
    135         }
    136     }
    137 }
    138 
    139 void MediaQueryMatcher::styleSelectorChanged()
    140 {
    141     ASSERT(m_document);
    142 
    143     ScriptState* scriptState = mainWorldScriptState(m_document->frame());
    144     if (!scriptState)
    145         return;
    146 
    147     ++m_evaluationRound;
    148     OwnPtr<MediaQueryEvaluator> evaluator = prepareEvaluator();
    149     if (!evaluator)
    150         return;
    151 
    152     for (size_t i = 0; i < m_listeners.size(); ++i)
    153         m_listeners[i]->evaluate(scriptState, evaluator.get());
    154 }
    155 
    156 }
    157