gecko-dev/dom/media/webaudio/MediaStreamAudioSourceNode.cpp

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim:set ts=2 sw=2 sts=2 et cindent: */
/* 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/. */

#include "MediaStreamAudioSourceNode.h"
#include "mozilla/dom/MediaStreamAudioSourceNodeBinding.h"
#include "AudioNodeEngine.h"
#include "AudioNodeExternalInputStream.h"
#include "AudioStreamTrack.h"
#include "nsIDocument.h"
#include "mozilla/CORSMode.h"

namespace mozilla {
namespace dom {

NS_IMPL_CYCLE_COLLECTION_CLASS(MediaStreamAudioSourceNode)

NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(MediaStreamAudioSourceNode)
  tmp->Destroy();
  NS_IMPL_CYCLE_COLLECTION_UNLINK(mInputStream)
  NS_IMPL_CYCLE_COLLECTION_UNLINK(mInputTrack)
NS_IMPL_CYCLE_COLLECTION_UNLINK_END_INHERITED(AudioNode)

NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(MediaStreamAudioSourceNode, AudioNode)
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mInputStream)
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mInputTrack)
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END

NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION_INHERITED(MediaStreamAudioSourceNode)
NS_INTERFACE_MAP_END_INHERITING(AudioNode)

NS_IMPL_ADDREF_INHERITED(MediaStreamAudioSourceNode, AudioNode)
NS_IMPL_RELEASE_INHERITED(MediaStreamAudioSourceNode, AudioNode)

MediaStreamAudioSourceNode::MediaStreamAudioSourceNode(AudioContext* aContext)
  : AudioNode(aContext,
              2,
              ChannelCountMode::Max,
              ChannelInterpretation::Speakers)
{
}

/* static */ already_AddRefed<MediaStreamAudioSourceNode>
MediaStreamAudioSourceNode::Create(AudioContext* aContext,
                                   DOMMediaStream* aStream, ErrorResult& aRv)
{
  RefPtr<MediaStreamAudioSourceNode> node =
    new MediaStreamAudioSourceNode(aContext);

  node->Init(aStream, aRv);
  if (aRv.Failed()) {
    return nullptr;
  }

  return node.forget();
}

void
MediaStreamAudioSourceNode::Init(DOMMediaStream* aMediaStream, ErrorResult& aRv)
{
  MOZ_ASSERT(aMediaStream);
  MediaStream* inputStream = aMediaStream->GetPlaybackStream();
  MediaStreamGraph* graph = Context()->Graph();
  if (NS_WARN_IF(graph != inputStream->Graph())) {
    aRv.Throw(NS_ERROR_DOM_NOT_SUPPORTED_ERR);
    return;
  }

  mInputStream = aMediaStream;
  AudioNodeEngine* engine = new MediaStreamAudioSourceNodeEngine(this);
  mStream = AudioNodeExternalInputStream::Create(graph, engine);
  mInputStream->AddConsumerToKeepAlive(static_cast<nsIDOMEventTarget*>(this));

  mInputStream->RegisterTrackListener(this);
  AttachToFirstTrack(mInputStream);
}

void
MediaStreamAudioSourceNode::Destroy()
{
  if (mInputStream) {
    mInputStream->UnregisterTrackListener(this);
    mInputStream = nullptr;
  }
  DetachFromTrack();
}

MediaStreamAudioSourceNode::~MediaStreamAudioSourceNode()
{
  Destroy();
}

void
MediaStreamAudioSourceNode::AttachToTrack(const RefPtr<MediaStreamTrack>& aTrack)
{
  MOZ_ASSERT(!mInputTrack);
  MOZ_ASSERT(aTrack->AsAudioStreamTrack());

  if (!mStream) {
    return;
  }

  mInputTrack = aTrack;
  ProcessedMediaStream* outputStream =
    static_cast<ProcessedMediaStream*>(mStream.get());
  mInputPort = mInputTrack->ForwardTrackContentsTo(outputStream);
  PrincipalChanged(mInputTrack); // trigger enabling/disabling of the connector
  mInputTrack->AddPrincipalChangeObserver(this);
}

void
MediaStreamAudioSourceNode::DetachFromTrack()
{
  if (mInputTrack) {
    mInputTrack->RemovePrincipalChangeObserver(this);
    mInputTrack = nullptr;
  }
  if (mInputPort) {
    mInputPort->Destroy();
    mInputPort = nullptr;
  }
}

void
MediaStreamAudioSourceNode::AttachToFirstTrack(const RefPtr<DOMMediaStream>& aMediaStream)
{
  nsTArray<RefPtr<AudioStreamTrack>> tracks;
  aMediaStream->GetAudioTracks(tracks);

  for (const RefPtr<AudioStreamTrack>& track : tracks) {
    if (track->Ended()) {
      continue;
    }

    AttachToTrack(track);
    MarkActive();
    return;
  }

  // There was no track available. We'll allow the node to be garbage collected.
  MarkInactive();
}

void
MediaStreamAudioSourceNode::NotifyTrackAdded(const RefPtr<MediaStreamTrack>& aTrack)
{
  if (mInputTrack) {
    return;
  }

  if (!aTrack->AsAudioStreamTrack()) {
    return;
  }

  AttachToTrack(aTrack);
}

void
MediaStreamAudioSourceNode::NotifyTrackRemoved(const RefPtr<MediaStreamTrack>& aTrack)
{
  if (aTrack != mInputTrack) {
    return;
  }

  DetachFromTrack();
  AttachToFirstTrack(mInputStream);
}

/**
 * Changes the principal. Note that this will be called on the main thread, but
 * changes will be enacted on the MediaStreamGraph thread. If the principal
 * change results in the document principal losing access to the stream, then
 * there needs to be other measures in place to ensure that any media that is
 * governed by the new stream principal is not available to the MediaStreamGraph
 * before this change completes. Otherwise, a site could get access to
 * media that they are not authorized to receive.
 *
 * One solution is to block the altered content, call this method, then dispatch
 * another change request to the MediaStreamGraph thread that allows the content
 * under the new principal to flow. This might be unnecessary if the principal
 * change is changing to be the document principal.
 */
void
MediaStreamAudioSourceNode::PrincipalChanged(MediaStreamTrack* aMediaStreamTrack)
{
  MOZ_ASSERT(aMediaStreamTrack == mInputTrack);

  bool subsumes = false;
  nsIDocument* doc = nullptr;
  if (nsPIDOMWindowInner* parent = Context()->GetParentObject()) {
    doc = parent->GetExtantDoc();
    if (doc) {
      nsIPrincipal* docPrincipal = doc->NodePrincipal();
      nsIPrincipal* trackPrincipal = aMediaStreamTrack->GetPrincipal();
      if (!trackPrincipal || NS_FAILED(docPrincipal->Subsumes(trackPrincipal, &subsumes))) {
        subsumes = false;
      }
    }
  }
  auto stream = static_cast<AudioNodeExternalInputStream*>(mStream.get());
  bool enabled = subsumes || aMediaStreamTrack->GetCORSMode() != CORS_NONE;
  stream->SetInt32Parameter(MediaStreamAudioSourceNodeEngine::ENABLE, enabled);

  if (!enabled && doc) {
    nsContentUtils::ReportToConsole(nsIScriptError::warningFlag,
                                    NS_LITERAL_CSTRING("Web Audio"),
                                    doc,
                                    nsContentUtils::eDOM_PROPERTIES,
                                    CrossOriginErrorString());
  }
}

size_t
MediaStreamAudioSourceNode::SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const
{
  // Future:
  // - mInputStream
  size_t amount = AudioNode::SizeOfExcludingThis(aMallocSizeOf);
  if (mInputPort) {
    amount += mInputPort->SizeOfIncludingThis(aMallocSizeOf);
  }
  return amount;
}

size_t
MediaStreamAudioSourceNode::SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const
{
  return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
}

void
MediaStreamAudioSourceNode::DestroyMediaStream()
{
  if (mInputPort) {
    mInputPort->Destroy();
    mInputPort = nullptr;
  }
  AudioNode::DestroyMediaStream();
}

JSObject*
MediaStreamAudioSourceNode::WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto)
{
  return MediaStreamAudioSourceNodeBinding::Wrap(aCx, this, aGivenProto);
}

} // namespace dom
} // namespace mozilla