910 lines
34 KiB
Python
910 lines
34 KiB
Python
import sys
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from types import MappingProxyType, DynamicClassAttribute
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# try _collections first to reduce startup cost
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try:
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from _collections import OrderedDict
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except ImportError:
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from collections import OrderedDict
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__all__ = [
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'EnumMeta',
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'Enum', 'IntEnum', 'Flag', 'IntFlag',
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'auto', 'unique',
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]
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def _is_descriptor(obj):
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"""Returns True if obj is a descriptor, False otherwise."""
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return (
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hasattr(obj, '__get__') or
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hasattr(obj, '__set__') or
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hasattr(obj, '__delete__'))
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def _is_dunder(name):
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"""Returns True if a __dunder__ name, False otherwise."""
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return (name[:2] == name[-2:] == '__' and
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name[2:3] != '_' and
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name[-3:-2] != '_' and
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len(name) > 4)
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def _is_sunder(name):
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"""Returns True if a _sunder_ name, False otherwise."""
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return (name[0] == name[-1] == '_' and
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name[1:2] != '_' and
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name[-2:-1] != '_' and
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len(name) > 2)
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def _make_class_unpicklable(cls):
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"""Make the given class un-picklable."""
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def _break_on_call_reduce(self, proto):
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raise TypeError('%r cannot be pickled' % self)
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cls.__reduce_ex__ = _break_on_call_reduce
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cls.__module__ = '<unknown>'
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_auto_null = object()
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class auto:
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"""
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Instances are replaced with an appropriate value in Enum class suites.
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"""
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value = _auto_null
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class _EnumDict(dict):
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"""Track enum member order and ensure member names are not reused.
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EnumMeta will use the names found in self._member_names as the
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enumeration member names.
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"""
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def __init__(self):
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super().__init__()
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self._member_names = []
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self._last_values = []
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self._ignore = []
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def __setitem__(self, key, value):
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"""Changes anything not dundered or not a descriptor.
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If an enum member name is used twice, an error is raised; duplicate
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values are not checked for.
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Single underscore (sunder) names are reserved.
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"""
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if _is_sunder(key):
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if key not in (
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'_order_', '_create_pseudo_member_',
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'_generate_next_value_', '_missing_', '_ignore_',
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):
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raise ValueError('_names_ are reserved for future Enum use')
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if key == '_generate_next_value_':
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setattr(self, '_generate_next_value', value)
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elif key == '_ignore_':
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if isinstance(value, str):
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value = value.replace(',',' ').split()
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else:
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value = list(value)
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self._ignore = value
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already = set(value) & set(self._member_names)
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if already:
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raise ValueError('_ignore_ cannot specify already set names: %r' % (already, ))
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elif _is_dunder(key):
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if key == '__order__':
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key = '_order_'
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elif key in self._member_names:
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# descriptor overwriting an enum?
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raise TypeError('Attempted to reuse key: %r' % key)
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elif key in self._ignore:
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pass
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elif not _is_descriptor(value):
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if key in self:
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# enum overwriting a descriptor?
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raise TypeError('%r already defined as: %r' % (key, self[key]))
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if isinstance(value, auto):
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if value.value == _auto_null:
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value.value = self._generate_next_value(key, 1, len(self._member_names), self._last_values[:])
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value = value.value
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self._member_names.append(key)
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self._last_values.append(value)
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super().__setitem__(key, value)
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# Dummy value for Enum as EnumMeta explicitly checks for it, but of course
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# until EnumMeta finishes running the first time the Enum class doesn't exist.
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# This is also why there are checks in EnumMeta like `if Enum is not None`
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Enum = None
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class EnumMeta(type):
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"""Metaclass for Enum"""
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@classmethod
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def __prepare__(metacls, cls, bases):
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# create the namespace dict
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enum_dict = _EnumDict()
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# inherit previous flags and _generate_next_value_ function
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member_type, first_enum = metacls._get_mixins_(bases)
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if first_enum is not None:
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enum_dict['_generate_next_value_'] = getattr(first_enum, '_generate_next_value_', None)
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return enum_dict
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def __new__(metacls, cls, bases, classdict):
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# an Enum class is final once enumeration items have been defined; it
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# cannot be mixed with other types (int, float, etc.) if it has an
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# inherited __new__ unless a new __new__ is defined (or the resulting
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# class will fail).
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#
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# remove any keys listed in _ignore_
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classdict.setdefault('_ignore_', []).append('_ignore_')
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ignore = classdict['_ignore_']
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for key in ignore:
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classdict.pop(key, None)
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member_type, first_enum = metacls._get_mixins_(bases)
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__new__, save_new, use_args = metacls._find_new_(classdict, member_type,
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first_enum)
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# save enum items into separate mapping so they don't get baked into
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# the new class
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enum_members = {k: classdict[k] for k in classdict._member_names}
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for name in classdict._member_names:
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del classdict[name]
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# adjust the sunders
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_order_ = classdict.pop('_order_', None)
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# check for illegal enum names (any others?)
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invalid_names = set(enum_members) & {'mro', }
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if invalid_names:
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raise ValueError('Invalid enum member name: {0}'.format(
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','.join(invalid_names)))
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# create a default docstring if one has not been provided
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if '__doc__' not in classdict:
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classdict['__doc__'] = 'An enumeration.'
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# create our new Enum type
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enum_class = super().__new__(metacls, cls, bases, classdict)
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enum_class._member_names_ = [] # names in definition order
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enum_class._member_map_ = OrderedDict() # name->value map
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enum_class._member_type_ = member_type
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# save DynamicClassAttribute attributes from super classes so we know
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# if we can take the shortcut of storing members in the class dict
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dynamic_attributes = {k for c in enum_class.mro()
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for k, v in c.__dict__.items()
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if isinstance(v, DynamicClassAttribute)}
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# Reverse value->name map for hashable values.
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enum_class._value2member_map_ = {}
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# If a custom type is mixed into the Enum, and it does not know how
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# to pickle itself, pickle.dumps will succeed but pickle.loads will
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# fail. Rather than have the error show up later and possibly far
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# from the source, sabotage the pickle protocol for this class so
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# that pickle.dumps also fails.
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#
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# However, if the new class implements its own __reduce_ex__, do not
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# sabotage -- it's on them to make sure it works correctly. We use
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# __reduce_ex__ instead of any of the others as it is preferred by
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# pickle over __reduce__, and it handles all pickle protocols.
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if '__reduce_ex__' not in classdict:
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if member_type is not object:
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methods = ('__getnewargs_ex__', '__getnewargs__',
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'__reduce_ex__', '__reduce__')
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if not any(m in member_type.__dict__ for m in methods):
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_make_class_unpicklable(enum_class)
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# instantiate them, checking for duplicates as we go
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# we instantiate first instead of checking for duplicates first in case
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# a custom __new__ is doing something funky with the values -- such as
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# auto-numbering ;)
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for member_name in classdict._member_names:
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value = enum_members[member_name]
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if not isinstance(value, tuple):
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args = (value, )
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else:
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args = value
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if member_type is tuple: # special case for tuple enums
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args = (args, ) # wrap it one more time
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if not use_args:
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enum_member = __new__(enum_class)
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if not hasattr(enum_member, '_value_'):
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enum_member._value_ = value
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else:
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enum_member = __new__(enum_class, *args)
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if not hasattr(enum_member, '_value_'):
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if member_type is object:
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enum_member._value_ = value
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else:
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enum_member._value_ = member_type(*args)
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value = enum_member._value_
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enum_member._name_ = member_name
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enum_member.__objclass__ = enum_class
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enum_member.__init__(*args)
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# If another member with the same value was already defined, the
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# new member becomes an alias to the existing one.
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for name, canonical_member in enum_class._member_map_.items():
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if canonical_member._value_ == enum_member._value_:
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enum_member = canonical_member
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break
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else:
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# Aliases don't appear in member names (only in __members__).
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enum_class._member_names_.append(member_name)
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# performance boost for any member that would not shadow
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# a DynamicClassAttribute
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if member_name not in dynamic_attributes:
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setattr(enum_class, member_name, enum_member)
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# now add to _member_map_
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enum_class._member_map_[member_name] = enum_member
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try:
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# This may fail if value is not hashable. We can't add the value
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# to the map, and by-value lookups for this value will be
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# linear.
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enum_class._value2member_map_[value] = enum_member
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except TypeError:
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pass
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# double check that repr and friends are not the mixin's or various
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# things break (such as pickle)
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for name in ('__repr__', '__str__', '__format__', '__reduce_ex__'):
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class_method = getattr(enum_class, name)
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obj_method = getattr(member_type, name, None)
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enum_method = getattr(first_enum, name, None)
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if obj_method is not None and obj_method is class_method:
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setattr(enum_class, name, enum_method)
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# replace any other __new__ with our own (as long as Enum is not None,
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# anyway) -- again, this is to support pickle
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if Enum is not None:
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# if the user defined their own __new__, save it before it gets
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# clobbered in case they subclass later
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if save_new:
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enum_class.__new_member__ = __new__
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enum_class.__new__ = Enum.__new__
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# py3 support for definition order (helps keep py2/py3 code in sync)
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if _order_ is not None:
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if isinstance(_order_, str):
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_order_ = _order_.replace(',', ' ').split()
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if _order_ != enum_class._member_names_:
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raise TypeError('member order does not match _order_')
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return enum_class
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def __bool__(self):
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"""
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classes/types should always be True.
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"""
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return True
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def __call__(cls, value, names=None, *, module=None, qualname=None, type=None, start=1):
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"""Either returns an existing member, or creates a new enum class.
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This method is used both when an enum class is given a value to match
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to an enumeration member (i.e. Color(3)) and for the functional API
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(i.e. Color = Enum('Color', names='RED GREEN BLUE')).
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When used for the functional API:
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`value` will be the name of the new class.
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`names` should be either a string of white-space/comma delimited names
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(values will start at `start`), or an iterator/mapping of name, value pairs.
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`module` should be set to the module this class is being created in;
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if it is not set, an attempt to find that module will be made, but if
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it fails the class will not be picklable.
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`qualname` should be set to the actual location this class can be found
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at in its module; by default it is set to the global scope. If this is
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not correct, unpickling will fail in some circumstances.
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`type`, if set, will be mixed in as the first base class.
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"""
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if names is None: # simple value lookup
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return cls.__new__(cls, value)
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# otherwise, functional API: we're creating a new Enum type
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return cls._create_(value, names, module=module, qualname=qualname, type=type, start=start)
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def __contains__(cls, member):
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if not isinstance(member, Enum):
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import warnings
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warnings.warn(
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"using non-Enums in containment checks will raise "
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"TypeError in Python 3.8",
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DeprecationWarning, 2)
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return isinstance(member, cls) and member._name_ in cls._member_map_
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def __delattr__(cls, attr):
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# nicer error message when someone tries to delete an attribute
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# (see issue19025).
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if attr in cls._member_map_:
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raise AttributeError(
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"%s: cannot delete Enum member." % cls.__name__)
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super().__delattr__(attr)
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def __dir__(self):
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return (['__class__', '__doc__', '__members__', '__module__'] +
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self._member_names_)
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def __getattr__(cls, name):
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"""Return the enum member matching `name`
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We use __getattr__ instead of descriptors or inserting into the enum
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class' __dict__ in order to support `name` and `value` being both
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properties for enum members (which live in the class' __dict__) and
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enum members themselves.
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"""
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if _is_dunder(name):
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raise AttributeError(name)
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try:
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return cls._member_map_[name]
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except KeyError:
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raise AttributeError(name) from None
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def __getitem__(cls, name):
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return cls._member_map_[name]
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def __iter__(cls):
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return (cls._member_map_[name] for name in cls._member_names_)
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def __len__(cls):
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return len(cls._member_names_)
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@property
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def __members__(cls):
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"""Returns a mapping of member name->value.
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This mapping lists all enum members, including aliases. Note that this
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is a read-only view of the internal mapping.
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"""
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return MappingProxyType(cls._member_map_)
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def __repr__(cls):
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return "<enum %r>" % cls.__name__
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def __reversed__(cls):
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return (cls._member_map_[name] for name in reversed(cls._member_names_))
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def __setattr__(cls, name, value):
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"""Block attempts to reassign Enum members.
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A simple assignment to the class namespace only changes one of the
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several possible ways to get an Enum member from the Enum class,
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resulting in an inconsistent Enumeration.
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"""
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member_map = cls.__dict__.get('_member_map_', {})
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if name in member_map:
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raise AttributeError('Cannot reassign members.')
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super().__setattr__(name, value)
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def _create_(cls, class_name, names, *, module=None, qualname=None, type=None, start=1):
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"""Convenience method to create a new Enum class.
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`names` can be:
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* A string containing member names, separated either with spaces or
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commas. Values are incremented by 1 from `start`.
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* An iterable of member names. Values are incremented by 1 from `start`.
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* An iterable of (member name, value) pairs.
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* A mapping of member name -> value pairs.
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"""
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metacls = cls.__class__
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bases = (cls, ) if type is None else (type, cls)
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_, first_enum = cls._get_mixins_(bases)
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classdict = metacls.__prepare__(class_name, bases)
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# special processing needed for names?
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if isinstance(names, str):
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names = names.replace(',', ' ').split()
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if isinstance(names, (tuple, list)) and names and isinstance(names[0], str):
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original_names, names = names, []
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last_values = []
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for count, name in enumerate(original_names):
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value = first_enum._generate_next_value_(name, start, count, last_values[:])
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last_values.append(value)
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names.append((name, value))
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# Here, names is either an iterable of (name, value) or a mapping.
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for item in names:
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if isinstance(item, str):
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member_name, member_value = item, names[item]
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else:
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member_name, member_value = item
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classdict[member_name] = member_value
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enum_class = metacls.__new__(metacls, class_name, bases, classdict)
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# TODO: replace the frame hack if a blessed way to know the calling
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# module is ever developed
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if module is None:
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try:
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module = sys._getframe(2).f_globals['__name__']
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except (AttributeError, ValueError) as exc:
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pass
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if module is None:
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_make_class_unpicklable(enum_class)
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else:
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enum_class.__module__ = module
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if qualname is not None:
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enum_class.__qualname__ = qualname
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return enum_class
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@staticmethod
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def _get_mixins_(bases):
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"""Returns the type for creating enum members, and the first inherited
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enum class.
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bases: the tuple of bases that was given to __new__
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"""
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if not bases:
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return object, Enum
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def _find_data_type(bases):
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for chain in bases:
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for base in chain.__mro__:
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if base is object:
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continue
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elif '__new__' in base.__dict__:
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if issubclass(base, Enum):
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continue
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return base
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# ensure final parent class is an Enum derivative, find any concrete
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# data type, and check that Enum has no members
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first_enum = bases[-1]
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if not issubclass(first_enum, Enum):
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raise TypeError("new enumerations should be created as "
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"`EnumName([mixin_type, ...] [data_type,] enum_type)`")
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member_type = _find_data_type(bases) or object
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if first_enum._member_names_:
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raise TypeError("Cannot extend enumerations")
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return member_type, first_enum
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@staticmethod
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def _find_new_(classdict, member_type, first_enum):
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"""Returns the __new__ to be used for creating the enum members.
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classdict: the class dictionary given to __new__
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member_type: the data type whose __new__ will be used by default
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first_enum: enumeration to check for an overriding __new__
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"""
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# now find the correct __new__, checking to see of one was defined
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# by the user; also check earlier enum classes in case a __new__ was
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# saved as __new_member__
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__new__ = classdict.get('__new__', None)
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# should __new__ be saved as __new_member__ later?
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save_new = __new__ is not None
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if __new__ is None:
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# check all possibles for __new_member__ before falling back to
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# __new__
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for method in ('__new_member__', '__new__'):
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for possible in (member_type, first_enum):
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target = getattr(possible, method, None)
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if target not in {
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None,
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None.__new__,
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object.__new__,
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Enum.__new__,
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}:
|
|
__new__ = target
|
|
break
|
|
if __new__ is not None:
|
|
break
|
|
else:
|
|
__new__ = object.__new__
|
|
|
|
# if a non-object.__new__ is used then whatever value/tuple was
|
|
# assigned to the enum member name will be passed to __new__ and to the
|
|
# new enum member's __init__
|
|
if __new__ is object.__new__:
|
|
use_args = False
|
|
else:
|
|
use_args = True
|
|
return __new__, save_new, use_args
|
|
|
|
|
|
class Enum(metaclass=EnumMeta):
|
|
"""Generic enumeration.
|
|
|
|
Derive from this class to define new enumerations.
|
|
|
|
"""
|
|
def __new__(cls, value):
|
|
# all enum instances are actually created during class construction
|
|
# without calling this method; this method is called by the metaclass'
|
|
# __call__ (i.e. Color(3) ), and by pickle
|
|
if type(value) is cls:
|
|
# For lookups like Color(Color.RED)
|
|
return value
|
|
# by-value search for a matching enum member
|
|
# see if it's in the reverse mapping (for hashable values)
|
|
try:
|
|
return cls._value2member_map_[value]
|
|
except KeyError:
|
|
# Not found, no need to do long O(n) search
|
|
pass
|
|
except TypeError:
|
|
# not there, now do long search -- O(n) behavior
|
|
for member in cls._member_map_.values():
|
|
if member._value_ == value:
|
|
return member
|
|
# still not found -- try _missing_ hook
|
|
try:
|
|
exc = None
|
|
result = cls._missing_(value)
|
|
except Exception as e:
|
|
exc = e
|
|
result = None
|
|
if isinstance(result, cls):
|
|
return result
|
|
else:
|
|
ve_exc = ValueError("%r is not a valid %s" % (value, cls.__name__))
|
|
if result is None and exc is None:
|
|
raise ve_exc
|
|
elif exc is None:
|
|
exc = TypeError(
|
|
'error in %s._missing_: returned %r instead of None or a valid member'
|
|
% (cls.__name__, result)
|
|
)
|
|
exc.__context__ = ve_exc
|
|
raise exc
|
|
|
|
def _generate_next_value_(name, start, count, last_values):
|
|
for last_value in reversed(last_values):
|
|
try:
|
|
return last_value + 1
|
|
except TypeError:
|
|
pass
|
|
else:
|
|
return start
|
|
|
|
@classmethod
|
|
def _missing_(cls, value):
|
|
raise ValueError("%r is not a valid %s" % (value, cls.__name__))
|
|
|
|
def __repr__(self):
|
|
return "<%s.%s: %r>" % (
|
|
self.__class__.__name__, self._name_, self._value_)
|
|
|
|
def __str__(self):
|
|
return "%s.%s" % (self.__class__.__name__, self._name_)
|
|
|
|
def __dir__(self):
|
|
added_behavior = [
|
|
m
|
|
for cls in self.__class__.mro()
|
|
for m in cls.__dict__
|
|
if m[0] != '_' and m not in self._member_map_
|
|
]
|
|
return (['__class__', '__doc__', '__module__'] + added_behavior)
|
|
|
|
def __format__(self, format_spec):
|
|
# mixed-in Enums should use the mixed-in type's __format__, otherwise
|
|
# we can get strange results with the Enum name showing up instead of
|
|
# the value
|
|
|
|
# pure Enum branch
|
|
if self._member_type_ is object:
|
|
cls = str
|
|
val = str(self)
|
|
# mix-in branch
|
|
else:
|
|
cls = self._member_type_
|
|
val = self._value_
|
|
return cls.__format__(val, format_spec)
|
|
|
|
def __hash__(self):
|
|
return hash(self._name_)
|
|
|
|
def __reduce_ex__(self, proto):
|
|
return self.__class__, (self._value_, )
|
|
|
|
# DynamicClassAttribute is used to provide access to the `name` and
|
|
# `value` properties of enum members while keeping some measure of
|
|
# protection from modification, while still allowing for an enumeration
|
|
# to have members named `name` and `value`. This works because enumeration
|
|
# members are not set directly on the enum class -- __getattr__ is
|
|
# used to look them up.
|
|
|
|
@DynamicClassAttribute
|
|
def name(self):
|
|
"""The name of the Enum member."""
|
|
return self._name_
|
|
|
|
@DynamicClassAttribute
|
|
def value(self):
|
|
"""The value of the Enum member."""
|
|
return self._value_
|
|
|
|
@classmethod
|
|
def _convert(cls, name, module, filter, source=None):
|
|
"""
|
|
Create a new Enum subclass that replaces a collection of global constants
|
|
"""
|
|
# convert all constants from source (or module) that pass filter() to
|
|
# a new Enum called name, and export the enum and its members back to
|
|
# module;
|
|
# also, replace the __reduce_ex__ method so unpickling works in
|
|
# previous Python versions
|
|
module_globals = vars(sys.modules[module])
|
|
if source:
|
|
source = vars(source)
|
|
else:
|
|
source = module_globals
|
|
# We use an OrderedDict of sorted source keys so that the
|
|
# _value2member_map is populated in the same order every time
|
|
# for a consistent reverse mapping of number to name when there
|
|
# are multiple names for the same number rather than varying
|
|
# between runs due to hash randomization of the module dictionary.
|
|
members = [
|
|
(name, source[name])
|
|
for name in source.keys()
|
|
if filter(name)]
|
|
try:
|
|
# sort by value
|
|
members.sort(key=lambda t: (t[1], t[0]))
|
|
except TypeError:
|
|
# unless some values aren't comparable, in which case sort by name
|
|
members.sort(key=lambda t: t[0])
|
|
cls = cls(name, members, module=module)
|
|
cls.__reduce_ex__ = _reduce_ex_by_name
|
|
module_globals.update(cls.__members__)
|
|
module_globals[name] = cls
|
|
return cls
|
|
|
|
|
|
class IntEnum(int, Enum):
|
|
"""Enum where members are also (and must be) ints"""
|
|
|
|
|
|
def _reduce_ex_by_name(self, proto):
|
|
return self.name
|
|
|
|
class Flag(Enum):
|
|
"""Support for flags"""
|
|
|
|
def _generate_next_value_(name, start, count, last_values):
|
|
"""
|
|
Generate the next value when not given.
|
|
|
|
name: the name of the member
|
|
start: the initital start value or None
|
|
count: the number of existing members
|
|
last_value: the last value assigned or None
|
|
"""
|
|
if not count:
|
|
return start if start is not None else 1
|
|
for last_value in reversed(last_values):
|
|
try:
|
|
high_bit = _high_bit(last_value)
|
|
break
|
|
except Exception:
|
|
raise TypeError('Invalid Flag value: %r' % last_value) from None
|
|
return 2 ** (high_bit+1)
|
|
|
|
@classmethod
|
|
def _missing_(cls, value):
|
|
original_value = value
|
|
if value < 0:
|
|
value = ~value
|
|
possible_member = cls._create_pseudo_member_(value)
|
|
if original_value < 0:
|
|
possible_member = ~possible_member
|
|
return possible_member
|
|
|
|
@classmethod
|
|
def _create_pseudo_member_(cls, value):
|
|
"""
|
|
Create a composite member iff value contains only members.
|
|
"""
|
|
pseudo_member = cls._value2member_map_.get(value, None)
|
|
if pseudo_member is None:
|
|
# verify all bits are accounted for
|
|
_, extra_flags = _decompose(cls, value)
|
|
if extra_flags:
|
|
raise ValueError("%r is not a valid %s" % (value, cls.__name__))
|
|
# construct a singleton enum pseudo-member
|
|
pseudo_member = object.__new__(cls)
|
|
pseudo_member._name_ = None
|
|
pseudo_member._value_ = value
|
|
# use setdefault in case another thread already created a composite
|
|
# with this value
|
|
pseudo_member = cls._value2member_map_.setdefault(value, pseudo_member)
|
|
return pseudo_member
|
|
|
|
def __contains__(self, other):
|
|
if not isinstance(other, self.__class__):
|
|
import warnings
|
|
warnings.warn(
|
|
"using non-Flags in containment checks will raise "
|
|
"TypeError in Python 3.8",
|
|
DeprecationWarning, 2)
|
|
return False
|
|
return other._value_ & self._value_ == other._value_
|
|
|
|
def __repr__(self):
|
|
cls = self.__class__
|
|
if self._name_ is not None:
|
|
return '<%s.%s: %r>' % (cls.__name__, self._name_, self._value_)
|
|
members, uncovered = _decompose(cls, self._value_)
|
|
return '<%s.%s: %r>' % (
|
|
cls.__name__,
|
|
'|'.join([str(m._name_ or m._value_) for m in members]),
|
|
self._value_,
|
|
)
|
|
|
|
def __str__(self):
|
|
cls = self.__class__
|
|
if self._name_ is not None:
|
|
return '%s.%s' % (cls.__name__, self._name_)
|
|
members, uncovered = _decompose(cls, self._value_)
|
|
if len(members) == 1 and members[0]._name_ is None:
|
|
return '%s.%r' % (cls.__name__, members[0]._value_)
|
|
else:
|
|
return '%s.%s' % (
|
|
cls.__name__,
|
|
'|'.join([str(m._name_ or m._value_) for m in members]),
|
|
)
|
|
|
|
def __bool__(self):
|
|
return bool(self._value_)
|
|
|
|
def __or__(self, other):
|
|
if not isinstance(other, self.__class__):
|
|
return NotImplemented
|
|
return self.__class__(self._value_ | other._value_)
|
|
|
|
def __and__(self, other):
|
|
if not isinstance(other, self.__class__):
|
|
return NotImplemented
|
|
return self.__class__(self._value_ & other._value_)
|
|
|
|
def __xor__(self, other):
|
|
if not isinstance(other, self.__class__):
|
|
return NotImplemented
|
|
return self.__class__(self._value_ ^ other._value_)
|
|
|
|
def __invert__(self):
|
|
members, uncovered = _decompose(self.__class__, self._value_)
|
|
inverted = self.__class__(0)
|
|
for m in self.__class__:
|
|
if m not in members and not (m._value_ & self._value_):
|
|
inverted = inverted | m
|
|
return self.__class__(inverted)
|
|
|
|
|
|
class IntFlag(int, Flag):
|
|
"""Support for integer-based Flags"""
|
|
|
|
@classmethod
|
|
def _missing_(cls, value):
|
|
if not isinstance(value, int):
|
|
raise ValueError("%r is not a valid %s" % (value, cls.__name__))
|
|
new_member = cls._create_pseudo_member_(value)
|
|
return new_member
|
|
|
|
@classmethod
|
|
def _create_pseudo_member_(cls, value):
|
|
pseudo_member = cls._value2member_map_.get(value, None)
|
|
if pseudo_member is None:
|
|
need_to_create = [value]
|
|
# get unaccounted for bits
|
|
_, extra_flags = _decompose(cls, value)
|
|
# timer = 10
|
|
while extra_flags:
|
|
# timer -= 1
|
|
bit = _high_bit(extra_flags)
|
|
flag_value = 2 ** bit
|
|
if (flag_value not in cls._value2member_map_ and
|
|
flag_value not in need_to_create
|
|
):
|
|
need_to_create.append(flag_value)
|
|
if extra_flags == -flag_value:
|
|
extra_flags = 0
|
|
else:
|
|
extra_flags ^= flag_value
|
|
for value in reversed(need_to_create):
|
|
# construct singleton pseudo-members
|
|
pseudo_member = int.__new__(cls, value)
|
|
pseudo_member._name_ = None
|
|
pseudo_member._value_ = value
|
|
# use setdefault in case another thread already created a composite
|
|
# with this value
|
|
pseudo_member = cls._value2member_map_.setdefault(value, pseudo_member)
|
|
return pseudo_member
|
|
|
|
def __or__(self, other):
|
|
if not isinstance(other, (self.__class__, int)):
|
|
return NotImplemented
|
|
result = self.__class__(self._value_ | self.__class__(other)._value_)
|
|
return result
|
|
|
|
def __and__(self, other):
|
|
if not isinstance(other, (self.__class__, int)):
|
|
return NotImplemented
|
|
return self.__class__(self._value_ & self.__class__(other)._value_)
|
|
|
|
def __xor__(self, other):
|
|
if not isinstance(other, (self.__class__, int)):
|
|
return NotImplemented
|
|
return self.__class__(self._value_ ^ self.__class__(other)._value_)
|
|
|
|
__ror__ = __or__
|
|
__rand__ = __and__
|
|
__rxor__ = __xor__
|
|
|
|
def __invert__(self):
|
|
result = self.__class__(~self._value_)
|
|
return result
|
|
|
|
|
|
def _high_bit(value):
|
|
"""returns index of highest bit, or -1 if value is zero or negative"""
|
|
return value.bit_length() - 1
|
|
|
|
def unique(enumeration):
|
|
"""Class decorator for enumerations ensuring unique member values."""
|
|
duplicates = []
|
|
for name, member in enumeration.__members__.items():
|
|
if name != member.name:
|
|
duplicates.append((name, member.name))
|
|
if duplicates:
|
|
alias_details = ', '.join(
|
|
["%s -> %s" % (alias, name) for (alias, name) in duplicates])
|
|
raise ValueError('duplicate values found in %r: %s' %
|
|
(enumeration, alias_details))
|
|
return enumeration
|
|
|
|
def _decompose(flag, value):
|
|
"""Extract all members from the value."""
|
|
# _decompose is only called if the value is not named
|
|
not_covered = value
|
|
negative = value < 0
|
|
# issue29167: wrap accesses to _value2member_map_ in a list to avoid race
|
|
# conditions between iterating over it and having more pseudo-
|
|
# members added to it
|
|
if negative:
|
|
# only check for named flags
|
|
flags_to_check = [
|
|
(m, v)
|
|
for v, m in list(flag._value2member_map_.items())
|
|
if m.name is not None
|
|
]
|
|
else:
|
|
# check for named flags and powers-of-two flags
|
|
flags_to_check = [
|
|
(m, v)
|
|
for v, m in list(flag._value2member_map_.items())
|
|
if m.name is not None or _power_of_two(v)
|
|
]
|
|
members = []
|
|
for member, member_value in flags_to_check:
|
|
if member_value and member_value & value == member_value:
|
|
members.append(member)
|
|
not_covered &= ~member_value
|
|
if not members and value in flag._value2member_map_:
|
|
members.append(flag._value2member_map_[value])
|
|
members.sort(key=lambda m: m._value_, reverse=True)
|
|
if len(members) > 1 and members[0].value == value:
|
|
# we have the breakdown, don't need the value member itself
|
|
members.pop(0)
|
|
return members, not_covered
|
|
|
|
def _power_of_two(value):
|
|
if value < 1:
|
|
return False
|
|
return value == 2 ** _high_bit(value)
|