content: /*
   * The Alluxio Open Foundation licenses this work under the Apache License, version 2.0
   * (the "License"). You may not use this work except in compliance with the License, which is
   * available at www.apache.org/licenses/LICENSE-2.0
   *
   * This software is distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
   * either express or implied, as more fully set forth in the License.
   *
   * See the NOTICE file distributed with this work for information regarding copyright ownership.
   */
  
  package alluxio.master.journal.checkpoint;
  
  import alluxio.proto.meta.InodeMeta;
  import alluxio.proto.meta.InodeMeta.Inode;
  
  import com.google.common.base.Preconditions;
  import com.google.common.base.Strings;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.PrintStream;
  import java.util.Optional;
  
  /**
   * Reads inode proto checkpoints.
   */
  public class InodeProtosCheckpointFormat implements CheckpointFormat {
    private static final String ENTRY_SEPARATOR = Strings.repeat("-", 80);
  
    @Override
    public InodeProtosCheckpointReader createReader(CheckpointInputStream in) {
      return new InodeProtosCheckpointReader(in);
    }
  
    @Override
    public void parseToHumanReadable(CheckpointInputStream in, PrintStream out) throws IOException {
      InodeProtosCheckpointReader reader = createReader(in);
      Optional<InodeMeta.Inode> entry;
      while ((entry = reader.read()).isPresent()) {
        out.println(ENTRY_SEPARATOR);
        out.println(entry.get());
      }
    }
  
    private static class InodeProtosCheckpointReader implements CheckpointReader {
      private final InputStream mStream;
  
      /**
       * @param in a checkpoint stream to read from
       */
      public InodeProtosCheckpointReader(CheckpointInputStream in) {
        Preconditions.checkState(in.getType() == CheckpointType.INODE_PROTOS);
        mStream = in;
      }
  
      /**
       * @return the next inode proto in the checkpoint, or empty if we've reached the end
       */
      public Optional<Inode> read() throws IOException {
        return Optional.ofNullable(InodeMeta.Inode.parseDelimitedFrom(mStream));
      }
    }
  }
  