CopyListing.java 文件源码

/**
 * Validate the final resulting path listing. Checks if there are duplicate entries. If preserving ACLs, checks that
 * file system can support ACLs. If preserving XAttrs, checks that file system can support XAttrs.
 *
 * @param pathToListFile path listing build by doBuildListing
 * @param options Input options to S3MapReduceCp
 * @throws IOException Any issues while checking for duplicates and throws
 * @throws DuplicateFileException if there are duplicates
 */
private void validateFinalListing(Path pathToListFile, S3MapReduceCpOptions options)
  throws DuplicateFileException, IOException {

  Configuration config = getConf();
  FileSystem fs = pathToListFile.getFileSystem(config);

  Path sortedList = sortListing(fs, config, pathToListFile);

  SequenceFile.Reader reader = new SequenceFile.Reader(config, SequenceFile.Reader.file(sortedList));
  try {
    Text lastKey = new Text("*"); // source relative path can never hold *
    CopyListingFileStatus lastFileStatus = new CopyListingFileStatus();

    Text currentKey = new Text();
    while (reader.next(currentKey)) {
      if (currentKey.equals(lastKey)) {
        CopyListingFileStatus currentFileStatus = new CopyListingFileStatus();
        reader.getCurrentValue(currentFileStatus);
        throw new DuplicateFileException("File "
            + lastFileStatus.getPath()
            + " and "
            + currentFileStatus.getPath()
            + " would cause duplicates. Aborting");
      }
      reader.getCurrentValue(lastFileStatus);
      lastKey.set(currentKey);
    }
  } finally {
    IOUtils.closeStream(reader);
  }
}