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

/*
 * Copyright (C) 2011, Google Inc. 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.
 * 2.  Redistributions in binary form must reproduce the above copyright
 *    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
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 */

#include "core/dom/DOMArrayBuffer.h"
#include "modules/webaudio/AsyncAudioDecoder.h"
#include "modules/webaudio/AudioBuffer.h"
#include "modules/webaudio/AudioBufferCallback.h"
#include "modules/webaudio/BaseAudioContext.h"
#include "platform/CrossThreadFunctional.h"
#include "platform/audio/AudioBus.h"
#include "platform/audio/AudioFileReader.h"
#include "platform/threading/BackgroundTaskRunner.h"
#include "public/platform/Platform.h"
#include "public/platform/WebTraceLocation.h"
#include "wtf/PtrUtil.h"

namespace blink {

// This threshold is determined by the assumption that the target audio
// file is compressed in AAC or MP3. The decoding time varies upon different
// audio file encoding types, but it is fair to assume the usage of compressed
// file.
static const unsigned kTaskSizeThresholdInByte = 512000;

void AsyncAudioDecoder::decodeAsync(DOMArrayBuffer* audioData,
                                    float sampleRate,
                                    AudioBufferCallback* successCallback,
                                    AudioBufferCallback* errorCallback,
                                    ScriptPromiseResolver* resolver,
                                    BaseAudioContext* context) {
  DCHECK(isMainThread());
  DCHECK(audioData);
  if (!audioData)
    return;

  BackgroundTaskRunner::TaskSize taskSize =
      audioData->byteLength() < kTaskSizeThresholdInByte
          ? BackgroundTaskRunner::TaskSizeShortRunningTask
          : BackgroundTaskRunner::TaskSizeLongRunningTask;
  BackgroundTaskRunner::postOnBackgroundThread(
      BLINK_FROM_HERE,
      crossThreadBind(&AsyncAudioDecoder::decodeOnBackgroundThread,
                      wrapCrossThreadPersistent(audioData), sampleRate,
                      wrapCrossThreadPersistent(successCallback),
                      wrapCrossThreadPersistent(errorCallback),
                      wrapCrossThreadPersistent(resolver),
                      wrapCrossThreadPersistent(context)),
      taskSize);
}

void AsyncAudioDecoder::decodeOnBackgroundThread(
    DOMArrayBuffer* audioData,
    float sampleRate,
    AudioBufferCallback* successCallback,
    AudioBufferCallback* errorCallback,
    ScriptPromiseResolver* resolver,
    BaseAudioContext* context) {
  DCHECK(!isMainThread());
  RefPtr<AudioBus> bus = createBusFromInMemoryAudioFile(
      audioData->data(), audioData->byteLength(), false, sampleRate);

  // Decoding is finished, but we need to do the callbacks on the main thread.
  // A reference to |*bus| is retained by WTF::Function and will be removed
  // after notifyComplete() is done.
  //
  // We also want to avoid notifying the main thread if AudioContext does not
  // exist any more.
  if (context) {
    Platform::current()->mainThread()->getWebTaskRunner()->postTask(
        BLINK_FROM_HERE,
        crossThreadBind(&AsyncAudioDecoder::notifyComplete,
                        wrapCrossThreadPersistent(audioData),
                        wrapCrossThreadPersistent(successCallback),
                        wrapCrossThreadPersistent(errorCallback), bus.release(),
                        wrapCrossThreadPersistent(resolver),
                        wrapCrossThreadPersistent(context)));
  }
}

void AsyncAudioDecoder::notifyComplete(DOMArrayBuffer*,
                                       AudioBufferCallback* successCallback,
                                       AudioBufferCallback* errorCallback,
                                       AudioBus* audioBus,
                                       ScriptPromiseResolver* resolver,
                                       BaseAudioContext* context) {
  DCHECK(isMainThread());

  AudioBuffer* audioBuffer = AudioBuffer::createFromAudioBus(audioBus);

  // If the context is available, let the context finish the notification.
  if (context) {
    context->handleDecodeAudioData(audioBuffer, resolver, successCallback,
                                   errorCallback);
  }
}

}  // namespace blink