content: /*
   * Copyright (C) 2016 The Android Open Source Project
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package com.google.android.exoplayer2.audio;
  
  import android.os.Handler;
  import android.os.SystemClock;
  import android.support.annotation.Nullable;
  import com.google.android.exoplayer2.C;
  import com.google.android.exoplayer2.Format;
  import com.google.android.exoplayer2.Renderer;
  import com.google.android.exoplayer2.decoder.DecoderCounters;
  import com.google.android.exoplayer2.util.Assertions;
  
  /**
   * Listener of audio {@link Renderer} events.
   */
  public interface AudioRendererEventListener {
  
    /**
     * Called when the renderer is enabled.
     *
     * @param counters {@link DecoderCounters} that will be updated by the renderer for as long as it
     *     remains enabled.
     */
    void onAudioEnabled(DecoderCounters counters);
  
    /**
     * Called when the audio session is set.
     *
     * @param audioSessionId The audio session id.
     */
    void onAudioSessionId(int audioSessionId);
  
    /**
     * Called when a decoder is created.
     *
     * @param decoderName The decoder that was created.
     * @param initializedTimestampMs {@link SystemClock#elapsedRealtime()} when initialization
     *     finished.
     * @param initializationDurationMs The time taken to initialize the decoder in milliseconds.
     */
    void onAudioDecoderInitialized(String decoderName, long initializedTimestampMs,
        long initializationDurationMs);
  
    /**
     * Called when the format of the media being consumed by the renderer changes.
     *
     * @param format The new format.
     */
    void onAudioInputFormatChanged(Format format);
  
    /**
     * Called when an {@link AudioSink} underrun occurs.
     *
     * @param bufferSize The size of the {@link AudioSink}'s buffer, in bytes.
     * @param bufferSizeMs The size of the {@link AudioSink}'s buffer, in milliseconds, if it is
     *     configured for PCM output. {@link C#TIME_UNSET} if it is configured for passthrough output,
     *     as the buffered media can have a variable bitrate so the duration may be unknown.
     * @param elapsedSinceLastFeedMs The time since the {@link AudioSink} was last fed data.
     */
    void onAudioSinkUnderrun(int bufferSize, long bufferSizeMs, long elapsedSinceLastFeedMs);
  
    /**
     * Called when the renderer is disabled.
     *
     * @param counters {@link DecoderCounters} that were updated by the renderer.
     */
    void onAudioDisabled(DecoderCounters counters);
  
    /**
     * Dispatches events to a {@link AudioRendererEventListener}.
     */
    final class EventDispatcher {
  
      @Nullable private final Handler handler;
      @Nullable private final AudioRendererEventListener listener;
  
      /**
       * @param handler A handler for dispatching events, or null if creating a dummy instance.
       * @param listener The listener to which events should be dispatched, or null if creating a
       *     dummy instance.
       */
      public EventDispatcher(@Nullable Handler handler,
          @Nullable AudioRendererEventListener listener) {
        this.handler = listener != null ? Assertions.checkNotNull(handler) : null;
        this.listener = listener;
      }
  
      /**
       * Invokes {@link AudioRendererEventListener#onAudioEnabled(DecoderCounters)}.
       */
      public void enabled(final DecoderCounters decoderCounters) {
        if (listener != null) {
          handler.post(new Runnable() {
            @Override
            public void run() {
              listener.onAudioEnabled(decoderCounters);
            }
          });
        }
      }
  
      /**
       * Invokes {@link AudioRendererEventListener#onAudioDecoderInitialized(String, long, long)}.
       */
      public void decoderInitialized(final String decoderName,
          final long initializedTimestampMs, final long initializationDurationMs) {
        if (listener != null) {
          handler.post(new Runnable() {
            @Override
            public void run() {
              listener.onAudioDecoderInitialized(decoderName, initializedTimestampMs,
                  initializationDurationMs);
            }
          });
        }
      }
  
      /**
       * Invokes {@link AudioRendererEventListener#onAudioInputFormatChanged(Format)}.
       */
      public void inputFormatChanged(final Format format) {
        if (listener != null) {
          handler.post(new Runnable() {
            @Override
            public void run() {
              listener.onAudioInputFormatChanged(format);
            }
          });
        }
      }
  
      /**
       * Invokes {@link AudioRendererEventListener#onAudioSinkUnderrun(int, long, long)}.
       */
      public void audioTrackUnderrun(final int bufferSize, final long bufferSizeMs,
          final long elapsedSinceLastFeedMs) {
        if (listener != null) {
          handler.post(new Runnable()  {
            @Override
            public void run() {
              listener.onAudioSinkUnderrun(bufferSize, bufferSizeMs, elapsedSinceLastFeedMs);
            }
          });
        }
      }
  
      /**
       * Invokes {@link AudioRendererEventListener#onAudioDisabled(DecoderCounters)}.
       */
      public void disabled(final DecoderCounters counters) {
        if (listener != null) {
          handler.post(new Runnable() {
            @Override
            public void run() {
              counters.ensureUpdated();
              listener.onAudioDisabled(counters);
            }
          });
        }
      }
  
      /**
       * Invokes {@link AudioRendererEventListener#onAudioSessionId(int)}.
       */
      public void audioSessionId(final int audioSessionId) {
        if (listener != null) {
          handler.post(new Runnable() {
            @Override
            public void run() {
              listener.onAudioSessionId(audioSessionId);
            }
          });
        }
      }
  
    }
  
  }
  