presto-hive/src/main/java/io/prestosql/plugin/hive/metastore/file/FileHiveMetastore.java/FileHiveMetastore/readPermissionsFile
class FileHiveMetastore:    private Set<HivePrivilegeInfo> readPermissionsFile(Path permissionFilePath)
    {
        return readFile("permissions", permissionFilePath, permissionsCodec).orElse(ImmutableList.of()).stream()
                .map(PermissionMetadata::toHivePrivilegeInfo)
                .collect(toImmutableSet());
    }