third_party/WebKit/Source/core/css/MediaQueryList.cpp

/*
 * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Library General Public
 *  License as published by the Free Software Foundation; either
 *  version 2 of the License, or (at your option) any later version.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Library General Public License for more details.
 *
 *  You should have received a copy of the GNU Library General Public License
 *  along with this library; see the file COPYING.LIB.  If not, write to
 *  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 *  Boston, MA 02110-1301, USA.
 */

#include "core/css/MediaQueryList.h"

#include "core/css/MediaList.h"
#include "core/css/MediaQueryEvaluator.h"
#include "core/css/MediaQueryListListener.h"
#include "core/css/MediaQueryMatcher.h"
#include "core/dom/Document.h"

namespace blink {

MediaQueryList* MediaQueryList::create(ExecutionContext* context,
                                       MediaQueryMatcher* matcher,
                                       MediaQuerySet* media) {
  MediaQueryList* list = new MediaQueryList(context, matcher, media);
  list->suspendIfNeeded();
  return list;
}

MediaQueryList::MediaQueryList(ExecutionContext* context,
                               MediaQueryMatcher* matcher,
                               MediaQuerySet* media)
    : ActiveScriptWrappable(this),
      ActiveDOMObject(context),
      m_matcher(matcher),
      m_media(media),
      m_matchesDirty(true),
      m_matches(false) {
  m_matcher->addMediaQueryList(this);
  updateMatches();
}

MediaQueryList::~MediaQueryList() {}

String MediaQueryList::media() const {
  return m_media->mediaText();
}

void MediaQueryList::addDeprecatedListener(EventListener* listener) {
  if (!listener)
    return;

  addEventListener(EventTypeNames::change, listener, false);
}

void MediaQueryList::removeDeprecatedListener(EventListener* listener) {
  if (!listener)
    return;

  removeEventListener(EventTypeNames::change, listener, false);
}

void MediaQueryList::addListener(MediaQueryListListener* listener) {
  if (!listener)
    return;

  m_listeners.add(listener);
}

void MediaQueryList::removeListener(MediaQueryListListener* listener) {
  if (!listener)
    return;

  m_listeners.remove(listener);
}

bool MediaQueryList::hasPendingActivity() const {
  return m_listeners.size() || hasEventListeners(EventTypeNames::change);
}

void MediaQueryList::contextDestroyed() {
  m_listeners.clear();
  removeAllEventListeners();
}

bool MediaQueryList::mediaFeaturesChanged(
    HeapVector<Member<MediaQueryListListener>>* listenersToNotify) {
  m_matchesDirty = true;
  if (!updateMatches())
    return false;
  for (const auto& listener : m_listeners) {
    listenersToNotify->append(listener);
  }
  return hasEventListeners(EventTypeNames::change);
}

bool MediaQueryList::updateMatches() {
  m_matchesDirty = false;
  if (m_matches != m_matcher->evaluate(m_media.get())) {
    m_matches = !m_matches;
    return true;
  }
  return false;
}

bool MediaQueryList::matches() {
  updateMatches();
  return m_matches;
}

DEFINE_TRACE(MediaQueryList) {
  visitor->trace(m_matcher);
  visitor->trace(m_media);
  visitor->trace(m_listeners);
  EventTargetWithInlineData::trace(visitor);
  ActiveDOMObject::trace(visitor);
}

const AtomicString& MediaQueryList::interfaceName() const {
  return EventTargetNames::MediaQueryList;
}

ExecutionContext* MediaQueryList::getExecutionContext() const {
  return ActiveDOMObject::getExecutionContext();
}

}  // namespace blink