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.metadata;
  
  import android.os.Handler;
  import android.os.Handler.Callback;
  import android.os.Looper;
  import android.os.Message;
  import com.google.android.exoplayer2.BaseRenderer;
  import com.google.android.exoplayer2.C;
  import com.google.android.exoplayer2.ExoPlaybackException;
  import com.google.android.exoplayer2.Format;
  import com.google.android.exoplayer2.FormatHolder;
  import com.google.android.exoplayer2.util.Assertions;
  import java.util.Arrays;
  
  /**
   * A renderer for metadata.
   */
  public final class MetadataRenderer extends BaseRenderer implements Callback {
  
    /**
     * @deprecated Use {@link MetadataOutput}.
     */
    @Deprecated
    public interface Output extends MetadataOutput {}
  
    private static final int MSG_INVOKE_RENDERER = 0;
    // TODO: Holding multiple pending metadata objects is temporary mitigation against
    // https://github.com/google/ExoPlayer/issues/1874. It should be removed once this issue has been
    // addressed.
    private static final int MAX_PENDING_METADATA_COUNT = 5;
  
    private final MetadataDecoderFactory decoderFactory;
    private final MetadataOutput output;
    private final Handler outputHandler;
    private final FormatHolder formatHolder;
    private final MetadataInputBuffer buffer;
    private final Metadata[] pendingMetadata;
    private final long[] pendingMetadataTimestamps;
  
    private int pendingMetadataIndex;
    private int pendingMetadataCount;
    private MetadataDecoder decoder;
    private boolean inputStreamEnded;
  
    /**
     * @param output The output.
     * @param outputLooper The looper associated with the thread on which the output should be called.
     *     If the output makes use of standard Android UI components, then this should normally be the
     *     looper associated with the application's main thread, which can be obtained using
     *     {@link android.app.Activity#getMainLooper()}. Null may be passed if the output should be
     *     called directly on the player's internal rendering thread.
     */
    public MetadataRenderer(MetadataOutput output, Looper outputLooper) {
      this(output, outputLooper, MetadataDecoderFactory.DEFAULT);
    }
  
    /**
     * @param output The output.
     * @param outputLooper The looper associated with the thread on which the output should be called.
     *     If the output makes use of standard Android UI components, then this should normally be the
     *     looper associated with the application's main thread, which can be obtained using
     *     {@link android.app.Activity#getMainLooper()}. Null may be passed if the output should be
     *     called directly on the player's internal rendering thread.
     * @param decoderFactory A factory from which to obtain {@link MetadataDecoder} instances.
     */
    public MetadataRenderer(MetadataOutput output, Looper outputLooper,
        MetadataDecoderFactory decoderFactory) {
      super(C.TRACK_TYPE_METADATA);
      this.output = Assertions.checkNotNull(output);
      this.outputHandler = outputLooper == null ? null : new Handler(outputLooper, this);
      this.decoderFactory = Assertions.checkNotNull(decoderFactory);
      formatHolder = new FormatHolder();
      buffer = new MetadataInputBuffer();
      pendingMetadata = new Metadata[MAX_PENDING_METADATA_COUNT];
      pendingMetadataTimestamps = new long[MAX_PENDING_METADATA_COUNT];
    }
  
    @Override
    public int supportsFormat(Format format) {
      if (decoderFactory.supportsFormat(format)) {
        return supportsFormatDrm(null, format.drmInitData) ? FORMAT_HANDLED : FORMAT_UNSUPPORTED_DRM;
      } else {
        return FORMAT_UNSUPPORTED_TYPE;
      }
    }
  
    @Override
    protected void onStreamChanged(Format[] formats, long offsetUs) throws ExoPlaybackException {
      decoder = decoderFactory.createDecoder(formats[0]);
    }
  
    @Override
    protected void onPositionReset(long positionUs, boolean joining) {
      flushPendingMetadata();
      inputStreamEnded = false;
    }
  
    @Override
    public void render(long positionUs, long elapsedRealtimeUs) throws ExoPlaybackException {
      if (!inputStreamEnded && pendingMetadataCount < MAX_PENDING_METADATA_COUNT) {
        buffer.clear();
        int result = readSource(formatHolder, buffer, false);
        if (result == C.RESULT_BUFFER_READ) {
          if (buffer.isEndOfStream()) {
            inputStreamEnded = true;
          } else if (buffer.isDecodeOnly()) {
            // Do nothing. Note this assumes that all metadata buffers can be decoded independently.
            // If we ever need to support a metadata format where this is not the case, we'll need to
            // pass the buffer to the decoder and discard the output.
          } else {
            buffer.subsampleOffsetUs = formatHolder.format.subsampleOffsetUs;
            buffer.flip();
            try {
              int index = (pendingMetadataIndex + pendingMetadataCount) % MAX_PENDING_METADATA_COUNT;
              pendingMetadata[index] = decoder.decode(buffer);
              pendingMetadataTimestamps[index] = buffer.timeUs;
              pendingMetadataCount++;
            } catch (MetadataDecoderException e) {
              throw ExoPlaybackException.createForRenderer(e, getIndex());
            }
          }
        }
      }
  
      if (pendingMetadataCount > 0 && pendingMetadataTimestamps[pendingMetadataIndex] <= positionUs) {
        invokeRenderer(pendingMetadata[pendingMetadataIndex]);
        pendingMetadata[pendingMetadataIndex] = null;
        pendingMetadataIndex = (pendingMetadataIndex + 1) % MAX_PENDING_METADATA_COUNT;
        pendingMetadataCount--;
      }
    }
  
    @Override
    protected void onDisabled() {
      flushPendingMetadata();
      decoder = null;
    }
  
    @Override
    public boolean isEnded() {
      return inputStreamEnded;
    }
  
    @Override
    public boolean isReady() {
      return true;
    }
  
    private void invokeRenderer(Metadata metadata) {
      if (outputHandler != null) {
        outputHandler.obtainMessage(MSG_INVOKE_RENDERER, metadata).sendToTarget();
      } else {
        invokeRendererInternal(metadata);
      }
    }
  
    private void flushPendingMetadata() {
      Arrays.fill(pendingMetadata, null);
      pendingMetadataIndex = 0;
      pendingMetadataCount = 0;
    }
  
    @SuppressWarnings("unchecked")
    @Override
    public boolean handleMessage(Message msg) {
      switch (msg.what) {
        case MSG_INVOKE_RENDERER:
          invokeRendererInternal((Metadata) msg.obj);
          return true;
        default:
          // Should never happen.
          throw new IllegalStateException();
      }
    }
  
    private void invokeRendererInternal(Metadata metadata) {
      output.onMetadata(metadata);
    }
  
  }
  