Current File : //lib/python3/dist-packages/dns/enum.py
# Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license
# Copyright (C) 2003-2017 Nominum, Inc.
#
# Permission to use, copy, modify, and distribute this software and its
# documentation for any purpose with or without fee is hereby granted,
# provided that the above copyright notice and this permission notice
# appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND NOMINUM DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM BE LIABLE FOR
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
# OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
import enum
from typing import Type, TypeVar, Union
TIntEnum = TypeVar("TIntEnum", bound="IntEnum")
class IntEnum(enum.IntEnum):
@classmethod
def _missing_(cls, value):
cls._check_value(value)
val = int.__new__(cls, value)
val._name_ = cls._extra_to_text(value, None) or f"{cls._prefix()}{value}"
val._value_ = value
return val
@classmethod
def _check_value(cls, value):
max = cls._maximum()
if not isinstance(value, int):
raise TypeError
if value < 0 or value > max:
name = cls._short_name()
raise ValueError(f"{name} must be an int between >= 0 and <= {max}")
@classmethod
def from_text(cls: Type[TIntEnum], text: str) -> TIntEnum:
text = text.upper()
try:
return cls[text]
except KeyError:
pass
value = cls._extra_from_text(text)
if value:
return value
prefix = cls._prefix()
if text.startswith(prefix) and text[len(prefix) :].isdigit():
value = int(text[len(prefix) :])
cls._check_value(value)
try:
return cls(value)
except ValueError:
return value
raise cls._unknown_exception_class()
@classmethod
def to_text(cls: Type[TIntEnum], value: int) -> str:
cls._check_value(value)
try:
text = cls(value).name
except ValueError:
text = None
text = cls._extra_to_text(value, text)
if text is None:
text = f"{cls._prefix()}{value}"
return text
@classmethod
def make(cls: Type[TIntEnum], value: Union[int, str]) -> TIntEnum:
"""Convert text or a value into an enumerated type, if possible.
*value*, the ``int`` or ``str`` to convert.
Raises a class-specific exception if a ``str`` is provided that
cannot be converted.
Raises ``ValueError`` if the value is out of range.
Returns an enumeration from the calling class corresponding to the
value, if one is defined, or an ``int`` otherwise.
"""
if isinstance(value, str):
return cls.from_text(value)
cls._check_value(value)
return cls(value)
@classmethod
def _maximum(cls):
raise NotImplementedError # pragma: no cover
@classmethod
def _short_name(cls):
return cls.__name__.lower()
@classmethod
def _prefix(cls):
return ""
@classmethod
def _extra_from_text(cls, text): # pylint: disable=W0613
return None
@classmethod
def _extra_to_text(cls, value, current_text): # pylint: disable=W0613
return current_text
@classmethod
def _unknown_exception_class(cls):
return ValueError
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