Method recoverFile

java/tools/src/java/org/apache/orc/tools/FileDump.java:556–645

(final Path corruptPath, final FileSystem fs,
      final Configuration conf, final List<Long> footerOffsets, final String backup)

  }

  private static void recoverFile(final Path corruptPath, final FileSystem fs,
      final Configuration conf, final List<Long> footerOffsets, final String backup)
      throws IOException {

    // first recover the file to .recovered file and then once successful rename it to actual file
    Path recoveredPath = getRecoveryFile(corruptPath);

    // make sure that file does not exist
    if (fs.exists(recoveredPath)) {
      fs.delete(recoveredPath, false);
    }

    // if there are no valid footers, the file should still be readable so create an empty orc file
    if (footerOffsets == null || footerOffsets.isEmpty()) {
      System.err.println("No readable footers found. Creating empty orc file.");
      TypeDescription schema = TypeDescription.createStruct();
      Writer writer = OrcFile.createWriter(recoveredPath,
          OrcFile.writerOptions(conf).setSchema(schema));
      writer.close();
    } else {
      FSDataInputStream fdis = fs.open(corruptPath);
      FileStatus fileStatus = fs.getFileStatus(corruptPath);
      // read corrupt file and copy it to recovered file until last valid footer
      FSDataOutputStream fdos = fs.create(recoveredPath, true,
          conf.getInt("io.file.buffer.size", 4096),
          fileStatus.getReplication(),
          fileStatus.getBlockSize());
      try {
        long fileLen = footerOffsets.get(footerOffsets.size() - 1);
        long remaining = fileLen;

        while (remaining > 0) {
          int toRead = (int) Math.min(DEFAULT_BLOCK_SIZE, remaining);
          byte[] data = new byte[toRead];
          long startPos = fileLen - remaining;
          fdis.readFully(startPos, data, 0, toRead);
          fdos.write(data);
          System.err.println("Copying data to recovery file - startPos: " + startPos +
              " toRead: " + toRead + " remaining: " + remaining);
          remaining = remaining - toRead;
        }
      } catch (Exception e) {
        fs.delete(recoveredPath, false);
        throw new IOException(e);
      } finally {
        fdis.close();
        fdos.close();
      }
    }

    // validate the recovered file once again and start moving corrupt files to backup folder
    if (isReadable(recoveredPath, conf, Long.MAX_VALUE)) {
      Path backupDataPath;
      Path backupDirPath;
      Path relativeCorruptPath;
      String scheme = corruptPath.toUri().getScheme();
      String authority = corruptPath.toUri().getAuthority();