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