third_party/WebKit/Source/modules/webaudio/AudioBasicInspectorNode.cpp

/*
 * Copyright (C) 2012, Intel Corporation. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1.  Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
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 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE
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#include "modules/webaudio/AudioBasicInspectorNode.h"
#include "modules/webaudio/AudioNodeInput.h"
#include "modules/webaudio/AudioNodeOutput.h"
#include "modules/webaudio/BaseAudioContext.h"

namespace blink {

AudioBasicInspectorHandler::AudioBasicInspectorHandler(
    NodeType node_type,
    AudioNode& node,
    float sample_rate,
    unsigned output_channel_count)
    : AudioHandler(node_type, node, sample_rate), need_automatic_pull_(false) {
  AddInput();
  AddOutput(output_channel_count);
}

// We override pullInputs() as an optimization allowing this node to take
// advantage of in-place processing, where the input is simply passed through
// unprocessed to the output.
// Note: this only applies if the input and output channel counts match.
void AudioBasicInspectorHandler::PullInputs(size_t frames_to_process) {
  // Render input stream - try to render directly into output bus for
  // pass-through processing where process() doesn't need to do anything...
  Input(0).Pull(Output(0).Bus(), frames_to_process);
}

AudioNode* AudioBasicInspectorNode::connect(AudioNode* destination,
                                            unsigned output_index,
                                            unsigned input_index,
                                            ExceptionState& exception_state) {
  DCHECK(IsMainThread());

  BaseAudioContext::GraphAutoLocker locker(context());

  AudioNode::connect(destination, output_index, input_index, exception_state);
  static_cast<AudioBasicInspectorHandler&>(Handler()).UpdatePullStatus();

  return destination;
}

void AudioBasicInspectorNode::disconnect(unsigned output_index,
                                         ExceptionState& exception_state) {
  DCHECK(IsMainThread());

  BaseAudioContext::GraphAutoLocker locker(context());

  AudioNode::disconnect(output_index, exception_state);
  static_cast<AudioBasicInspectorHandler&>(Handler()).UpdatePullStatus();
}

void AudioBasicInspectorHandler::CheckNumberOfChannelsForInput(
    AudioNodeInput* input) {
  DCHECK(Context()->IsAudioThread());
  DCHECK(Context()->IsGraphOwner());

  DCHECK_EQ(input, &this->Input(0));
  if (input != &this->Input(0))
    return;

  unsigned number_of_channels = input->NumberOfChannels();

  if (number_of_channels != Output(0).NumberOfChannels()) {
    // This will propagate the channel count to any nodes connected further
    // downstream in the graph.
    Output(0).SetNumberOfChannels(number_of_channels);
  }

  AudioHandler::CheckNumberOfChannelsForInput(input);

  UpdatePullStatus();
}

void AudioBasicInspectorHandler::UpdatePullStatus() {
  DCHECK(Context()->IsGraphOwner());

  if (Output(0).IsConnected()) {
    // When an AudioBasicInspectorNode is connected to a downstream node, it
    // will get pulled by the downstream node, thus remove it from the context's
    // automatic pull list.
    if (need_automatic_pull_) {
      Context()->GetDeferredTaskHandler().RemoveAutomaticPullNode(this);
      need_automatic_pull_ = false;
    }
  } else {
    unsigned number_of_input_connections =
        Input(0).NumberOfRenderingConnections();
    if (number_of_input_connections && !need_automatic_pull_) {
      // When an AudioBasicInspectorNode is not connected to any downstream node
      // while still connected from upstream node(s), add it to the context's
      // automatic pull list.
      Context()->GetDeferredTaskHandler().AddAutomaticPullNode(this);
      need_automatic_pull_ = true;
    } else if (!number_of_input_connections && need_automatic_pull_) {
      // The AudioBasicInspectorNode is connected to nothing and is
      // not an AnalyserNode, remove it from the context's automatic
      // pull list.  AnalyserNode's need to be pulled even with no
      // inputs so that the internal state gets updated to hold the
      // right time and FFT data.
      Context()->GetDeferredTaskHandler().RemoveAutomaticPullNode(this);
      need_automatic_pull_ = false;
    }
  }
}

}  // namespace blink