private List<RolePrincipalGrant> getRoleGrants(String principalName, PrincipalType principalType)
      throws MetaException, TException, HiveAuthzPluginException {
    GetRoleGrantsForPrincipalRequest req = new GetRoleGrantsForPrincipalRequest(principalName, principalType);
    IMetaStoreClient metastoreClient = metastoreClientFactory.getHiveMetastoreClient();
    GetRoleGrantsForPrincipalResponse resp = metastoreClient.get_role_grants_for_principal(req);
    return resp.getPrincipalGrants();
  }
(Re-)initialize currentRoleNames if necessary.
@throws HiveAuthzPluginException
ql/src/java/org/apache/hadoop/hive/ql/security/authorization/plugin/sqlstd/SQLStdHiveAccessController.java