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.upstream;
  
  import android.net.Uri;
  import com.google.android.exoplayer2.C;
  import com.google.android.exoplayer2.util.Assertions;
  import java.io.IOException;
  
  /**
   * Tees data into a {@link DataSink} as the data is read.
   */
  public final class TeeDataSource implements DataSource {
  
    private final DataSource upstream;
    private final DataSink dataSink;
  
    /**
     * @param upstream The upstream {@link DataSource}.
     * @param dataSink The {@link DataSink} into which data is written.
     */
    public TeeDataSource(DataSource upstream, DataSink dataSink) {
      this.upstream = Assertions.checkNotNull(upstream);
      this.dataSink = Assertions.checkNotNull(dataSink);
    }
  
    @Override
    public long open(DataSpec dataSpec) throws IOException {
      long dataLength = upstream.open(dataSpec);
      if (dataSpec.length == C.LENGTH_UNSET && dataLength != C.LENGTH_UNSET) {
        // Reconstruct dataSpec in order to provide the resolved length to the sink.
        dataSpec = new DataSpec(dataSpec.uri, dataSpec.absoluteStreamPosition, dataSpec.position,
            dataLength, dataSpec.key, dataSpec.flags);
      }
      dataSink.open(dataSpec);
      return dataLength;
    }
  
    @Override
    public int read(byte[] buffer, int offset, int max) throws IOException {
      int num = upstream.read(buffer, offset, max);
      if (num > 0) {
        // TODO: Consider continuing even if disk writes fail.
        dataSink.write(buffer, offset, num);
      }
      return num;
    }
  
    @Override
    public Uri getUri() {
      return upstream.getUri();
    }
  
    @Override
    public void close() throws IOException {
      try {
        upstream.close();
      } finally {
        dataSink.close();
      }
    }
  
  }
  