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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 "core/css/MediaQueryMatcher.h"
     22 
     23 #include "core/css/MediaList.h"
     24 #include "core/css/MediaQueryEvaluator.h"
     25 #include "core/css/MediaQueryList.h"
     26 #include "core/css/MediaQueryListListener.h"
     27 #include "core/css/resolver/StyleResolver.h"
     28 #include "core/dom/Document.h"
     29 #include "core/frame/Frame.h"
     30 #include "core/frame/FrameView.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 AtomicString MediaQueryMatcher::mediaType() const
     70 {
     71     if (!m_document || !m_document->frame() || !m_document->frame()->view())
     72         return nullAtom;
     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 nullptr;
     81 
     82     Element* documentElement = m_document->documentElement();
     83     if (!documentElement)
     84         return nullptr;
     85 
     86     StyleResolver& styleResolver = m_document->ensureStyleResolver();
     87     RefPtr<RenderStyle> rootStyle = styleResolver.styleForElement(documentElement, 0 /*defaultParent*/, DisallowStyleSharing, MatchOnlyUserAgentRules);
     88 
     89     return adoptPtr(new MediaQueryEvaluator(mediaType(), m_document->frame(), rootStyle.get()));
     90 }
     91 
     92 bool MediaQueryMatcher::evaluate(const MediaQuerySet* media)
     93 {
     94     if (!media)
     95         return false;
     96 
     97     OwnPtr<MediaQueryEvaluator> evaluator(prepareEvaluator());
     98     return evaluator && evaluator->eval(media);
     99 }
    100 
    101 PassRefPtr<MediaQueryList> MediaQueryMatcher::matchMedia(const String& query)
    102 {
    103     if (!m_document)
    104         return 0;
    105 
    106     RefPtr<MediaQuerySet> media = MediaQuerySet::create(query);
    107     // Add warning message to inspector whenever dpi/dpcm values are used for "screen" media.
    108     reportMediaQueryWarningIfNeeded(m_document, media.get());
    109     return MediaQueryList::create(this, media, evaluate(media.get()));
    110 }
    111 
    112 void MediaQueryMatcher::addListener(PassRefPtr<MediaQueryListListener> listener, PassRefPtr<MediaQueryList> query)
    113 {
    114     if (!m_document)
    115         return;
    116 
    117     for (size_t i = 0; i < m_listeners.size(); ++i) {
    118         if (*m_listeners[i]->listener() == *listener && m_listeners[i]->query() == query)
    119             return;
    120     }
    121 
    122     m_listeners.append(adoptPtr(new Listener(listener, query)));
    123 }
    124 
    125 void MediaQueryMatcher::removeListener(MediaQueryListListener* listener, MediaQueryList* query)
    126 {
    127     if (!m_document)
    128         return;
    129 
    130     for (size_t i = 0; i < m_listeners.size(); ++i) {
    131         if (*m_listeners[i]->listener() == *listener && m_listeners[i]->query() == query) {
    132             m_listeners.remove(i);
    133             return;
    134         }
    135     }
    136 }
    137 
    138 void MediaQueryMatcher::styleResolverChanged()
    139 {
    140     if (!m_document)
    141         return;
    142 
    143     ScriptState* scriptState = m_document->frame() ? mainWorldScriptState(m_document->frame()) : 0;
    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