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,
                                       RefPtr<MediaQuerySet> media) {
  return new MediaQueryList(context, matcher, RefPtr<MediaQuerySet>(media));
}

MediaQueryList::MediaQueryList(ExecutionContext* context,
                               MediaQueryMatcher* matcher,
                               RefPtr<MediaQuerySet> media)
    : ContextLifecycleObserver(context),
      matcher_(matcher),
      media_(media),
      matches_dirty_(true),
      matches_(false) {
  matcher_->AddMediaQueryList(this);
  UpdateMatches();
}

MediaQueryList::~MediaQueryList() {}

String MediaQueryList::media() const {
  return 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;

  listeners_.insert(listener);
}

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

  listeners_.erase(listener);
}

bool MediaQueryList::HasPendingActivity() const {
  return GetExecutionContext() &&
         (listeners_.size() || HasEventListeners(EventTypeNames::change));
}

void MediaQueryList::ContextDestroyed(ExecutionContext*) {
  listeners_.clear();
  RemoveAllEventListeners();
}

bool MediaQueryList::MediaFeaturesChanged(
    HeapVector<Member<MediaQueryListListener>>* listeners_to_notify) {
  matches_dirty_ = true;
  if (!UpdateMatches())
    return false;
  for (const auto& listener : listeners_) {
    listeners_to_notify->push_back(listener);
  }
  return HasEventListeners(EventTypeNames::change);
}

bool MediaQueryList::UpdateMatches() {
  matches_dirty_ = false;
  if (matches_ != matcher_->Evaluate(media_.Get())) {
    matches_ = !matches_;
    return true;
  }
  return false;
}

bool MediaQueryList::matches() {
  UpdateMatches();
  return matches_;
}

DEFINE_TRACE(MediaQueryList) {
  visitor->Trace(matcher_);
  visitor->Trace(listeners_);
  EventTargetWithInlineData::Trace(visitor);
  ContextLifecycleObserver::Trace(visitor);
}

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

ExecutionContext* MediaQueryList::GetExecutionContext() const {
  return ContextLifecycleObserver::GetExecutionContext();
}

}  // namespace blink