content: /*
   * Copyright (C) 2018 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.offline;
  
  import android.net.Uri;
  import androidx.annotation.Nullable;
  import com.google.android.exoplayer2.upstream.ParsingLoadable.Parser;
  import java.io.IOException;
  import java.io.InputStream;
  import java.util.List;
  
  /**
   * A manifest parser that includes only the streams identified by the given stream keys.
   *
   * @param <T> The {@link FilterableManifest} type.
   */
  public final class FilteringManifestParser<T extends FilterableManifest<T>> implements Parser<T> {
  
    private final Parser<? extends T> parser;
    @Nullable private final List<StreamKey> streamKeys;
  
    /**
     * @param parser A parser for the manifest that will be filtered.
     * @param streamKeys The stream keys. If null or empty then filtering will not occur.
     */
    public FilteringManifestParser(Parser<? extends T> parser, @Nullable List<StreamKey> streamKeys) {
      this.parser = parser;
      this.streamKeys = streamKeys;
    }
  
    @Override
    public T parse(Uri uri, InputStream inputStream) throws IOException {
      T manifest = parser.parse(uri, inputStream);
      return streamKeys == null || streamKeys.isEmpty() ? manifest : manifest.copy(streamKeys);
    }
  }
  