/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/* vim: set ts=8 sts=2 et sw=2 tw=80: */

/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

/* implements DOM interface for querying and observing media queries */

#include "mozilla/dom/MediaQueryList.h"

#include "mozilla/dom/MediaQueryListEvent.h"

#include "mozilla/dom/MediaList.h"

#include "mozilla/dom/EventTarget.h"

#include "mozilla/dom/EventTargetBinding.h"

#include "nsPresContext.h"

#include "nsIDocument.h"

#define ONCHANGE_STRING NS_LITERAL_STRING("change")

namespace mozilla {

namespace dom {

MediaQueryList::MediaQueryList(nsIDocument* aDocument,

                               const nsAString& aMediaQueryList,

                               CallerType aCallerType)

  : DOMEventTargetHelper(aDocument->GetInnerWindow())

  , mDocument(aDocument)

  , mMatches(false)

  , mMatchesValid(false)

{

  mMediaList = MediaList::Create(aMediaQueryList, aCallerType);

  KeepAliveIfHasListenersFor(ONCHANGE_STRING);

}

MediaQueryList::~MediaQueryList()

{}

NS_IMPL_CYCLE_COLLECTION_CLASS(MediaQueryList)

NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(MediaQueryList,

                                                  DOMEventTargetHelper)

  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mDocument)

NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END

NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN_INHERITED(MediaQueryList,

                                                DOMEventTargetHelper)

  if (tmp->mDocument) {

    static_cast<LinkedListElement<MediaQueryList>*>(tmp)->remove();

    NS_IMPL_CYCLE_COLLECTION_UNLINK(mDocument)

  }

  tmp->Disconnect();

  NS_IMPL_CYCLE_COLLECTION_UNLINK_PRESERVED_WRAPPER

NS_IMPL_CYCLE_COLLECTION_UNLINK_END

NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(MediaQueryList)

NS_INTERFACE_MAP_END_INHERITING(DOMEventTargetHelper)

NS_IMPL_ADDREF_INHERITED(MediaQueryList, DOMEventTargetHelper)

NS_IMPL_RELEASE_INHERITED(MediaQueryList, DOMEventTargetHelper)

void

MediaQueryList::GetMedia(nsAString &aMedia)

{

  mMediaList->GetText(aMedia);

}

bool

MediaQueryList::Matches()

{

  if (!mMatchesValid) {

    MOZ_ASSERT(!HasListeners(),

               "when listeners present, must keep mMatches current");

    RecomputeMatches();

  }

  return mMatches;

}

void

MediaQueryList::AddListener(EventListener* aListener, ErrorResult& aRv)

{

  if (!aListener) {

    return;

  }

  AddEventListenerOptionsOrBoolean options;

  options.SetAsBoolean() = false;

  AddEventListener(ONCHANGE_STRING, aListener, options, false, aRv);

}

void

MediaQueryList::EventListenerAdded(nsAtom* aType)

{

  // HasListeners() might still be false if the added thing wasn't a

  // listener we care about.

  if (!mMatchesValid && HasListeners()) {

    RecomputeMatches();

  }

  DOMEventTargetHelper::EventListenerAdded(aType);

}

void

MediaQueryList::RemoveListener(EventListener* aListener, ErrorResult& aRv)

{

  if (!aListener) {

    return;

  }

  EventListenerOptionsOrBoolean options;

  options.SetAsBoolean() = false;

  RemoveEventListener(ONCHANGE_STRING, aListener, options, aRv);

}

bool

MediaQueryList::HasListeners()

{

  return HasListenersFor(ONCHANGE_STRING);

}

void

MediaQueryList::Disconnect()

{

  DisconnectFromOwner();

  IgnoreKeepAliveIfHasListenersFor(ONCHANGE_STRING);

}

void

MediaQueryList::RecomputeMatches()

{

  mMatches = false;

  if (!mDocument) {

    return;

  }

  // FIXME(emilio, bug 1490401): We shouldn't need a pres context to evaluate

  // media queries.

  nsPresContext* presContext = mDocument->GetPresContext();

  if (!presContext && mDocument->GetParentDocument()) {

    // Flush frames on the parent so our prescontext will get

    // created if needed.

    mDocument->GetParentDocument()->FlushPendingNotifications(FlushType::Frames);

    // That might have killed our document, so recheck that.

    if (!mDocument) {

      return;

    }

    presContext = mDocument->GetPresContext();

  }

  if (!presContext) {

    // XXXbz What's the right behavior here?  Spec doesn't say.

    return;

  }

  mMatches = mMediaList->Matches(presContext);

  mMatchesValid = true;

}

nsISupports*

MediaQueryList::GetParentObject() const

{

  return mDocument;

}

JSObject*

MediaQueryList::WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto)

{

  return MediaQueryList_Binding::Wrap(aCx, this, aGivenProto);

}

void

MediaQueryList::MaybeNotify()

{

  mMatchesValid = false;

  if (!HasListeners()) {

    return;

  }

  bool oldMatches = mMatches;

  RecomputeMatches();

  // No need to notify the change.

  if (mMatches == oldMatches) {

    return;

  }

  MediaQueryListEventInit init;

  init.mBubbles = false;

  init.mCancelable = false;

  init.mMatches = mMatches;

  mMediaList->GetText(init.mMedia);

  RefPtr<MediaQueryListEvent> event =

    MediaQueryListEvent::Constructor(this, ONCHANGE_STRING, init);

  event->SetTrusted(true);

  DispatchEvent(*event);

}

size_t

MediaQueryList::SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const

{

  size_t n = 0;

  // mMediaList is reference counted, but it's created and primarily owned

  // by this MediaQueryList object.

  n += mMediaList->SizeOfIncludingThis(aMallocSizeOf);

  return n;

}

} // namespace dom

} // namespace mozilla