public static List<String> doGetAliasesFromPath(Map<Path, List<String>> pathToAliases, Path dir) {
    if (pathToAliases == null) {
      return Collections.emptyList();
    }
    Path path = getMatchingPath(pathToAliases, dir);
    return pathToAliases.get(path);
  }
Get the list of aliases from the opeerator tree that are needed for the path
@param pathToAliases  mapping from path to aliases
@param dir            The path to look for
ql/src/java/org/apache/hadoop/hive/ql/io/HiveFileFormatUtils.java