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116 lines
3.6 KiB
116 lines
3.6 KiB
# Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license |
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# Copyright (C) 2003-2017 Nominum, Inc. |
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# |
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# Permission to use, copy, modify, and distribute this software and its |
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# documentation for any purpose with or without fee is hereby granted, |
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# provided that the above copyright notice and this permission notice |
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# appear in all copies. |
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# |
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# THE SOFTWARE IS PROVIDED "AS IS" AND NOMINUM DISCLAIMS ALL WARRANTIES |
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# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF |
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# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM BE LIABLE FOR |
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# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
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# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN |
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# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT |
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# OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
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import enum |
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from typing import Type, TypeVar, Union |
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TIntEnum = TypeVar("TIntEnum", bound="IntEnum") |
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class IntEnum(enum.IntEnum): |
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@classmethod |
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def _missing_(cls, value): |
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cls._check_value(value) |
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val = int.__new__(cls, value) |
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val._name_ = cls._extra_to_text(value, None) or f"{cls._prefix()}{value}" |
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val._value_ = value |
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return val |
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@classmethod |
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def _check_value(cls, value): |
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max = cls._maximum() |
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if not isinstance(value, int): |
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raise TypeError |
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if value < 0 or value > max: |
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name = cls._short_name() |
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raise ValueError(f"{name} must be an int between >= 0 and <= {max}") |
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@classmethod |
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def from_text(cls: Type[TIntEnum], text: str) -> TIntEnum: |
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text = text.upper() |
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try: |
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return cls[text] |
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except KeyError: |
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pass |
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value = cls._extra_from_text(text) |
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if value: |
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return value |
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prefix = cls._prefix() |
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if text.startswith(prefix) and text[len(prefix) :].isdigit(): |
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value = int(text[len(prefix) :]) |
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cls._check_value(value) |
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try: |
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return cls(value) |
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except ValueError: |
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return value |
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raise cls._unknown_exception_class() |
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@classmethod |
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def to_text(cls: Type[TIntEnum], value: int) -> str: |
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cls._check_value(value) |
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try: |
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text = cls(value).name |
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except ValueError: |
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text = None |
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text = cls._extra_to_text(value, text) |
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if text is None: |
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text = f"{cls._prefix()}{value}" |
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return text |
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@classmethod |
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def make(cls: Type[TIntEnum], value: Union[int, str]) -> TIntEnum: |
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"""Convert text or a value into an enumerated type, if possible. |
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*value*, the ``int`` or ``str`` to convert. |
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Raises a class-specific exception if a ``str`` is provided that |
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cannot be converted. |
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Raises ``ValueError`` if the value is out of range. |
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Returns an enumeration from the calling class corresponding to the |
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value, if one is defined, or an ``int`` otherwise. |
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""" |
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if isinstance(value, str): |
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return cls.from_text(value) |
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cls._check_value(value) |
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return cls(value) |
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@classmethod |
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def _maximum(cls): |
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raise NotImplementedError # pragma: no cover |
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@classmethod |
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def _short_name(cls): |
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return cls.__name__.lower() |
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@classmethod |
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def _prefix(cls): |
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return "" |
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@classmethod |
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def _extra_from_text(cls, text): # pylint: disable=W0613 |
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return None |
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@classmethod |
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def _extra_to_text(cls, value, current_text): # pylint: disable=W0613 |
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return current_text |
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@classmethod |
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def _unknown_exception_class(cls): |
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return ValueError
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