| # -*- coding: utf-8 -*- |
| """ |
| hyperframe/flags |
| ~~~~~~~~~~~~~~~~ |
| |
| Defines basic Flag and Flags data structures. |
| """ |
| import collections |
| |
| |
| Flag = collections.namedtuple("Flag", ["name", "bit"]) |
| |
| |
| class Flags(collections.MutableSet): |
| """ |
| 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): |
| self._valid_flags = set(flag.name for flag in defined_flags) |
| self._flags = set() |
| |
| def __contains__(self, x): |
| return self._flags.__contains__(x) |
| |
| def __iter__(self): |
| return self._flags.__iter__() |
| |
| def __len__(self): |
| return self._flags.__len__() |
| |
| def discard(self, value): |
| return self._flags.discard(value) |
| |
| def add(self, value): |
| if value not in self._valid_flags: |
| raise ValueError( |
| "Unexpected flag: {}. Valid flags are: {}".format( |
| value, self._valid_flags |
| ) |
| ) |
| return self._flags.add(value) |
