gecko/content/media/webaudio/AudioNode.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 "AudioNode.h"
#include "AudioContext.h"
#include "nsContentUtils.h"
#include "mozilla/ErrorResult.h"

namespace mozilla {
namespace dom {

inline void
ImplCycleCollectionTraverse(nsCycleCollectionTraversalCallback& aCallback,
                            AudioNode::InputNode& aField,
                            const char* aName,
                            unsigned aFlags)
{
  CycleCollectionNoteChild(aCallback, aField.mInputNode.get(), aName, aFlags);
}

inline void
ImplCycleCollectionUnlink(nsCycleCollectionTraversalCallback& aCallback,
                          AudioNode::InputNode& aField,
                          const char* aName,
                          unsigned aFlags)
{
  aField.mInputNode = nullptr;
}

NS_IMPL_CYCLE_COLLECTION_3(AudioNode, mContext, mInputNodes, mOutputNodes)

NS_IMPL_CYCLE_COLLECTING_ADDREF(AudioNode)
NS_IMPL_CYCLE_COLLECTING_RELEASE(AudioNode)
NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(AudioNode)
  NS_INTERFACE_MAP_ENTRY(nsISupports)
NS_INTERFACE_MAP_END

AudioNode::AudioNode(AudioContext* aContext)
  : mContext(aContext)
{
  MOZ_ASSERT(aContext);
}

AudioNode::~AudioNode()
{
  MOZ_ASSERT(mInputNodes.IsEmpty());
  MOZ_ASSERT(mOutputNodes.IsEmpty());
}

static uint32_t
FindIndexOfNodeWithPorts(const nsTArray<AudioNode::InputNode>& aInputNodes, const AudioNode* aNode,
                         uint32_t aInputPort, uint32_t aOutputPort)
{
  for (uint32_t i = 0; i < aInputNodes.Length(); ++i) {
    if (aInputNodes[i].mInputNode == aNode &&
        aInputNodes[i].mInputPort == aInputPort &&
        aInputNodes[i].mOutputPort == aOutputPort) {
      return i;
    }
  }
  return nsTArray<AudioNode::InputNode>::NoIndex;
}

void
AudioNode::Connect(AudioNode& aDestination, uint32_t aOutput,
                   uint32_t aInput, ErrorResult& aRv)
{
  if (aOutput >= NumberOfOutputs() ||
      aInput >= aDestination.NumberOfInputs()) {
    aRv.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
    return;
  }

  if (Context() != aDestination.Context()) {
    aRv.Throw(NS_ERROR_DOM_SYNTAX_ERR);
    return;
  }

  if (FindIndexOfNodeWithPorts(aDestination.mInputNodes, this, aInput, aOutput) !=
      nsTArray<AudioNode::InputNode>::NoIndex) {
    // connection already exists.
    return;
  }

  // The MediaStreamGraph will handle cycle detection. We don't need to do it
  // here.

  // Addref this temporarily so the refcount bumping below doesn't destroy us
  nsRefPtr<AudioNode> kungFuDeathGrip = this;

  mOutputNodes.AppendElement(&aDestination);
  InputNode* input = aDestination.mInputNodes.AppendElement();
  input->mInputNode = this;
  input->mInputPort = aInput;
  input->mOutputPort = aOutput;
}

void
AudioNode::Disconnect(uint32_t aOutput, ErrorResult& aRv)
{
  if (aOutput >= NumberOfOutputs()) {
    aRv.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
    return;
  }

  // Disconnect everything connected to this output. First find the
  // corresponding inputs and remove them.
  nsAutoTArray<nsRefPtr<AudioNode>,4> outputsToUpdate;

  for (int32_t i = mOutputNodes.Length() - 1; i >= 0; --i) {
    AudioNode* dest = mOutputNodes[i];
    for (int32_t j = dest->mInputNodes.Length() - 1; j >= 0; --j) {
      InputNode& input = dest->mInputNodes[j];
      if (input.mInputNode == this && input.mOutputPort == aOutput) {
        dest->mInputNodes.RemoveElementAt(j);
        // Remove one instance of 'dest' from mOutputNodes. There could be
        // others, and it's not correct to remove them all since some of them
        // could be for different output ports.
        *outputsToUpdate.AppendElement() = mOutputNodes[i].forget();
        mOutputNodes.RemoveElementAt(i);
        break;
      }
    }
  }
}

}
}