# -*- coding: utf-8 -*- """ hyperframe/flags ~~~~~~~~~~~~~~~~ Defines basic Flag and Flags data structures. """ from collections.abc import MutableSet from typing import NamedTuple, Iterable, Set, Iterator class Flag(NamedTuple): name: str bit: int class Flags(MutableSet): # type: ignore """ A simple MutableSet implementation that will only accept known flags as elements. Will behave like a regular set(), except that a ValueError will be thrown when .add()ing unexpected flags. """ def __init__(self, defined_flags: Iterable[Flag]): self._valid_flags = set(flag.name for flag in defined_flags) self._flags: Set[str] = set() def __repr__(self) -> str: return repr(sorted(list(self._flags))) def __contains__(self, x: object) -> bool: return self._flags.__contains__(x) def __iter__(self) -> Iterator[str]: return self._flags.__iter__() def __len__(self) -> int: return self._flags.__len__() def discard(self, value: str) -> None: return self._flags.discard(value) def add(self, value: str) -> None: if value not in self._valid_flags: raise ValueError( "Unexpected flag: {}. Valid flags are: {}".format( value, self._valid_flags ) ) return self._flags.add(value)