public List<HdfsFileStatusWithId> getFiles(FileSystem fs, Ref<Boolean> useFileIds) throws IOException {
      // If the list was not populated before, do it now
      if (files == null && fs != null) {
        files = HdfsUtils.listFileStatusWithId(fs, baseDirPath, useFileIds, false, HIDDEN_FILES_PATH_FILTER);
      }
      return files;
    }
Returns the files from the base directory.
The list is either populated by AcidUtils or it will be listed through the provided FileSystem object.
If the list was not filled and no FS is provided, returns null.
@param fs FileSystem optional
@param useFileIds to use fileId based listing or not. Optional
@return list of files in the base directory
@throws IOException ex
ql/src/java/org/apache/hadoop/hive/ql/io/AcidUtils.java