cpython/enum.py at 3.9 · python/cpython

cpython/Lib/enum.py /

Jump to

Code definitions

_is_descriptor Function _is_dunder Function _is_sunder Function _is_private Function _make_class_unpicklable Function _break_on_call_reduce Function auto Class _EnumDict Class init Function setitem Function EnumMeta Class prepare Function new Function bool Function call Function contains Function delattr Function dir Function getattr Function getitem Function iter Function len Function members Function repr Function reversed Function setattr Function _create_ Function _convert_ Function _check_for_existing_members Function _get_mixins_ Function _find_data_type Function _find_new_ Function Enum Class new Function _generate_next_value_ Function _missing_ Function repr Function str Function dir Function format Function hash Function __reduce_ex__ Function name Function value Function IntEnum Class _reduce_ex_by_name Function Flag Class _generate_next_value_ Function _missing_ Function _create_pseudo_member_ Function contains Function repr Function str Function bool Function or Function and Function xor Function invert Function IntFlag Class _missing_ Function _create_pseudo_member_ Function or Function and Function xor Function invert Function _high_bit Function unique Function _decompose Function

Code navigation index up-to-date

Cannot retrieve contributors at this time

1044 lines (926 sloc) 38.5 KB

	import sys
	from types import MappingProxyType, DynamicClassAttribute


	__all__ = [
	'EnumMeta',
	'Enum', 'IntEnum', 'Flag', 'IntFlag',
	'auto', 'unique',
	]


	def _is_descriptor(obj):
	"""
	Returns True if obj is a descriptor, False otherwise.
	"""
	return (
	hasattr(obj, '__get__') or
	hasattr(obj, '__set__') or
	hasattr(obj, '__delete__')
	)

	def _is_dunder(name):
	"""
	Returns True if a __dunder__ name, False otherwise.
	"""
	return (
	len(name) > 4 and
	name[:2] == name[-2:] == '__' and
	name[2] != '_' and
	name[-3] != '_'
	)

	def _is_sunder(name):
	"""
	Returns True if a _sunder_ name, False otherwise.
	"""
	return (
	len(name) > 2 and
	name[0] == name[-1] == '_' and
	name[1:2] != '_' and
	name[-2:-1] != '_'
	)

	def _is_private(cls_name, name):
	# do not use `re` as `re` imports `enum`
	pattern = '_%s__' % (cls_name, )
	if (
	len(name) >= 5
	and name.startswith(pattern)
	and name[len(pattern)] != '_'
	and (name[-1] != '_' or name[-2] != '_')
	):
	return True
	else:
	return False

	def _make_class_unpicklable(cls):
	"""
	Make the given class un-picklable.
	"""
	def _break_on_call_reduce(self, proto):
	raise TypeError('%r cannot be pickled' % self)
	cls.__reduce_ex__ = _break_on_call_reduce
	cls.__module__ = '<unknown>'

	_auto_null = object()
	class auto:
	"""
	Instances are replaced with an appropriate value in Enum class suites.
	"""
	value = _auto_null


	class _EnumDict(dict):
	"""
	Track enum member order and ensure member names are not reused.

	EnumMeta will use the names found in self._member_names as the
	enumeration member names.
	"""
	def __init__(self):
	super().__init__()
	self._member_names = []
	self._last_values = []
	self._ignore = []
	self._auto_called = False

	def __setitem__(self, key, value):
	"""
	Changes anything not dundered or not a descriptor.

	If an enum member name is used twice, an error is raised; duplicate
	values are not checked for.

	Single underscore (sunder) names are reserved.
	"""
	if _is_private(self._cls_name, key):
	import warnings
	warnings.warn(
	"private variables, such as %r, will be normal attributes in 3.10"
	% (key, ),
	DeprecationWarning,
	stacklevel=2,
	)
	if _is_sunder(key):
	if key not in (
	'_order_', '_create_pseudo_member_',
	'_generate_next_value_', '_missing_', '_ignore_',
	):
	raise ValueError('_names_ are reserved for future Enum use')
	if key == '_generate_next_value_':
	# check if members already defined as auto()
	if self._auto_called:
	raise TypeError("_generate_next_value_ must be defined before members")
	setattr(self, '_generate_next_value', value)
	elif key == '_ignore_':
	if isinstance(value, str):
	value = value.replace(',',' ').split()
	else:
	value = list(value)
	self._ignore = value
	already = set(value) & set(self._member_names)
	if already:
	raise ValueError(
	'_ignore_ cannot specify already set names: %r'
	% (already, )
	)
	elif _is_dunder(key):
	if key == '__order__':
	key = '_order_'
	elif key in self._member_names:
	# descriptor overwriting an enum?
	raise TypeError('Attempted to reuse key: %r' % key)
	elif key in self._ignore:
	pass
	elif not _is_descriptor(value):
	if key in self:
	# enum overwriting a descriptor?
	raise TypeError('%r already defined as: %r' % (key, self[key]))
	if isinstance(value, auto):
	if value.value == _auto_null:
	value.value = self._generate_next_value(
	key,
	1,
	len(self._member_names),
	self._last_values[:],
	)
	self._auto_called = True
	value = value.value
	self._member_names.append(key)
	self._last_values.append(value)
	super().__setitem__(key, value)


	# Dummy value for Enum as EnumMeta explicitly checks for it, but of course
	# until EnumMeta finishes running the first time the Enum class doesn't exist.
	# This is also why there are checks in EnumMeta like `if Enum is not None`
	Enum = None

	class EnumMeta(type):
	"""
	Metaclass for Enum
	"""
	@classmethod
	def __prepare__(metacls, cls, bases, **kwds):
	# check that previous enum members do not exist
	metacls._check_for_existing_members(cls, bases)
	# create the namespace dict
	enum_dict = _EnumDict()
	enum_dict._cls_name = cls
	# inherit previous flags and _generate_next_value_ function
	member_type, first_enum = metacls._get_mixins_(cls, bases)
	if first_enum is not None:
	enum_dict['_generate_next_value_'] = getattr(
	first_enum, '_generate_next_value_', None,
	)
	return enum_dict

	def __new__(metacls, cls, bases, classdict, **kwds):
	# an Enum class is final once enumeration items have been defined; it
	# cannot be mixed with other types (int, float, etc.) if it has an
	# inherited __new__ unless a new __new__ is defined (or the resulting
	# class will fail).
	#
	# remove any keys listed in _ignore_
	classdict.setdefault('_ignore_', []).append('_ignore_')
	ignore = classdict['_ignore_']
	for key in ignore:
	classdict.pop(key, None)
	member_type, first_enum = metacls._get_mixins_(cls, bases)
	__new__, save_new, use_args = metacls._find_new_(
	classdict, member_type, first_enum,
	)

	# save enum items into separate mapping so they don't get baked into
	# the new class
	enum_members = {k: classdict[k] for k in classdict._member_names}
	for name in classdict._member_names:
	del classdict[name]

	# adjust the sunders
	_order_ = classdict.pop('_order_', None)

	# check for illegal enum names (any others?)
	invalid_names = set(enum_members) & {'mro', ''}
	if invalid_names:
	raise ValueError('Invalid enum member name: {0}'.format(
	','.join(invalid_names)))

	# create a default docstring if one has not been provided
	if '__doc__' not in classdict:
	classdict['__doc__'] = 'An enumeration.'

	enum_class = super().__new__(metacls, cls, bases, classdict, **kwds)
	enum_class._member_names_ = [] # names in definition order
	enum_class._member_map_ = {} # name->value map
	enum_class._member_type_ = member_type

	# save DynamicClassAttribute attributes from super classes so we know
	# if we can take the shortcut of storing members in the class dict
	dynamic_attributes = {
	k for c in enum_class.mro()
	for k, v in c.__dict__.items()
	if isinstance(v, DynamicClassAttribute)
	}

	# Reverse value->name map for hashable values.
	enum_class._value2member_map_ = {}

	# If a custom type is mixed into the Enum, and it does not know how
	# to pickle itself, pickle.dumps will succeed but pickle.loads will
	# fail. Rather than have the error show up later and possibly far
	# from the source, sabotage the pickle protocol for this class so
	# that pickle.dumps also fails.
	#
	# However, if the new class implements its own __reduce_ex__, do not
	# sabotage -- it's on them to make sure it works correctly. We use
	# __reduce_ex__ instead of any of the others as it is preferred by
	# pickle over __reduce__, and it handles all pickle protocols.
	if '__reduce_ex__' not in classdict:
	if member_type is not object:
	methods = ('__getnewargs_ex__', '__getnewargs__',
	'__reduce_ex__', '__reduce__')
	if not any(m in member_type.__dict__ for m in methods):
	if '__new__' in classdict:
	# too late, sabotage
	_make_class_unpicklable(enum_class)
	else:
	# final attempt to verify that pickling would work:
	# travel mro until __new__ is found, checking for
	# __reduce__ and friends along the way -- if any of them
	# are found before/when __new__ is found, pickling should
	# work
	sabotage = None
	for chain in bases:
	for base in chain.__mro__:
	if base is object:
	continue
	elif any(m in base.__dict__ for m in methods):
	# found one, we're good
	sabotage = False
	break
	elif '__new__' in base.__dict__:
	# not good
	sabotage = True
	break
	if sabotage is not None:
	break
	if sabotage:
	_make_class_unpicklable(enum_class)
	# instantiate them, checking for duplicates as we go
	# we instantiate first instead of checking for duplicates first in case
	# a custom __new__ is doing something funky with the values -- such as
	# auto-numbering ;)
	for member_name in classdict._member_names:
	value = enum_members[member_name]
	if not isinstance(value, tuple):
	args = (value, )
	else:
	args = value
	if member_type is tuple: # special case for tuple enums
	args = (args, ) # wrap it one more time
	if not use_args:
	enum_member = __new__(enum_class)
	if not hasattr(enum_member, '_value_'):
	enum_member._value_ = value
	else:
	enum_member = __new__(enum_class, *args)
	if not hasattr(enum_member, '_value_'):
	if member_type is object:
	enum_member._value_ = value
	else:
	enum_member._value_ = member_type(*args)
	value = enum_member._value_
	enum_member._name_ = member_name
	enum_member.__objclass__ = enum_class
	enum_member.__init__(*args)
	# If another member with the same value was already defined, the
	# new member becomes an alias to the existing one.
	for name, canonical_member in enum_class._member_map_.items():
	if canonical_member._value_ == enum_member._value_:
	enum_member = canonical_member
	break
	else:
	# Aliases don't appear in member names (only in __members__).
	enum_class._member_names_.append(member_name)
	# performance boost for any member that would not shadow
	# a DynamicClassAttribute
	if member_name not in dynamic_attributes:
	setattr(enum_class, member_name, enum_member)
	# now add to _member_map_
	enum_class._member_map_[member_name] = enum_member
	try:
	# This may fail if value is not hashable. We can't add the value
	# to the map, and by-value lookups for this value will be
	# linear.
	enum_class._value2member_map_[value] = enum_member
	except TypeError:
	pass

	# double check that repr and friends are not the mixin's or various
	# things break (such as pickle)
	# however, if the method is defined in the Enum itself, don't replace
	# it
	for name in ('__repr__', '__str__', '__format__', '__reduce_ex__'):
	if name in classdict:
	continue
	class_method = getattr(enum_class, name)
	obj_method = getattr(member_type, name, None)
	enum_method = getattr(first_enum, name, None)
	if obj_method is not None and obj_method is class_method:
	setattr(enum_class, name, enum_method)

	# replace any other __new__ with our own (as long as Enum is not None,
	# anyway) -- again, this is to support pickle
	if Enum is not None:
	# if the user defined their own __new__, save it before it gets
	# clobbered in case they subclass later
	if save_new:
	enum_class.__new_member__ = __new__
	enum_class.__new__ = Enum.__new__

	# py3 support for definition order (helps keep py2/py3 code in sync)
	if _order_ is not None:
	if isinstance(_order_, str):
	_order_ = _order_.replace(',', ' ').split()
	if _order_ != enum_class._member_names_:
	raise TypeError('member order does not match _order_')

	return enum_class

	def __bool__(self):
	"""
	classes/types should always be True.
	"""
	return True

	def __call__(cls, value, names=None, *, module=None, qualname=None, type=None, start=1):
	"""
	Either returns an existing member, or creates a new enum class.

	This method is used both when an enum class is given a value to match
	to an enumeration member (i.e. Color(3)) and for the functional API
	(i.e. Color = Enum('Color', names='RED GREEN BLUE')).

	When used for the functional API:

	`value` will be the name of the new class.

	`names` should be either a string of white-space/comma delimited names
	(values will start at `start`), or an iterator/mapping of name, value pairs.

	`module` should be set to the module this class is being created in;
	if it is not set, an attempt to find that module will be made, but if
	it fails the class will not be picklable.

	`qualname` should be set to the actual location this class can be found
	at in its module; by default it is set to the global scope. If this is
	not correct, unpickling will fail in some circumstances.

	`type`, if set, will be mixed in as the first base class.
	"""
	if names is None: # simple value lookup
	return cls.__new__(cls, value)
	# otherwise, functional API: we're creating a new Enum type
	return cls._create_(
	value,
	names,
	module=module,
	qualname=qualname,
	type=type,
	start=start,
	)

	def __contains__(cls, member):
	if not isinstance(member, Enum):
	raise TypeError(
	"unsupported operand type(s) for 'in': '%s' and '%s'" % (
	type(member).__qualname__, cls.__class__.__qualname__))
	return isinstance(member, cls) and member._name_ in cls._member_map_

	def __delattr__(cls, attr):
	# nicer error message when someone tries to delete an attribute
	# (see issue19025).
	if attr in cls._member_map_:
	raise AttributeError("%s: cannot delete Enum member." % cls.__name__)
	super().__delattr__(attr)

	def __dir__(self):
	return (
	['__class__', '__doc__', '__members__', '__module__']
	+ self._member_names_
	)

	def __getattr__(cls, name):
	"""
	Return the enum member matching `name`

	We use __getattr__ instead of descriptors or inserting into the enum
	class' __dict__ in order to support `name` and `value` being both
	properties for enum members (which live in the class' __dict__) and
	enum members themselves.
	"""
	if _is_dunder(name):
	raise AttributeError(name)
	try:
	return cls._member_map_[name]
	except KeyError:
	raise AttributeError(name) from None

	def __getitem__(cls, name):
	return cls._member_map_[name]

	def __iter__(cls):
	"""
	Returns members in definition order.
	"""
	return (cls._member_map_[name] for name in cls._member_names_)

	def __len__(cls):
	return len(cls._member_names_)

	@property
	def __members__(cls):
	"""
	Returns a mapping of member name->value.

	This mapping lists all enum members, including aliases. Note that this
	is a read-only view of the internal mapping.
	"""
	return MappingProxyType(cls._member_map_)

	def __repr__(cls):
	return "<enum %r>" % cls.__name__

	def __reversed__(cls):
	"""
	Returns members in reverse definition order.
	"""
	return (cls._member_map_[name] for name in reversed(cls._member_names_))

	def __setattr__(cls, name, value):
	"""
	Block attempts to reassign Enum members.

	A simple assignment to the class namespace only changes one of the
	several possible ways to get an Enum member from the Enum class,
	resulting in an inconsistent Enumeration.
	"""
	member_map = cls.__dict__.get('_member_map_', {})
	if name in member_map:
	raise AttributeError('Cannot reassign members.')
	super().__setattr__(name, value)

	def _create_(cls, class_name, names, *, module=None, qualname=None, type=None, start=1):
	"""
	Convenience method to create a new Enum class.

	`names` can be:

	* A string containing member names, separated either with spaces or
	commas. Values are incremented by 1 from `start`.
	* An iterable of member names. Values are incremented by 1 from `start`.
	* An iterable of (member name, value) pairs.
	* A mapping of member name -> value pairs.
	"""
	metacls = cls.__class__
	bases = (cls, ) if type is None else (type, cls)
	_, first_enum = cls._get_mixins_(cls, bases)
	classdict = metacls.__prepare__(class_name, bases)

	# special processing needed for names?
	if isinstance(names, str):
	names = names.replace(',', ' ').split()
	if isinstance(names, (tuple, list)) and names and isinstance(names[0], str):
	original_names, names = names, []
	last_values = []
	for count, name in enumerate(original_names):
	value = first_enum._generate_next_value_(name, start, count, last_values[:])
	last_values.append(value)
	names.append((name, value))

	# Here, names is either an iterable of (name, value) or a mapping.
	for item in names:
	if isinstance(item, str):
	member_name, member_value = item, names[item]
	else:
	member_name, member_value = item
	classdict[member_name] = member_value
	enum_class = metacls.__new__(metacls, class_name, bases, classdict)

	# TODO: replace the frame hack if a blessed way to know the calling
	# module is ever developed
	if module is None:
	try:
	module = sys._getframe(2).f_globals['__name__']
	except (AttributeError, ValueError, KeyError):
	pass
	if module is None:
	_make_class_unpicklable(enum_class)
	else:
	enum_class.__module__ = module
	if qualname is not None:
	enum_class.__qualname__ = qualname

	return enum_class

	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
	# _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.
	members = [
	(name, value)
	for name, value in source.items()
	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

	@staticmethod
	def _check_for_existing_members(class_name, bases):
	for chain in bases:
	for base in chain.__mro__:
	if issubclass(base, Enum) and base._member_names_:
	raise TypeError(
	"%s: cannot extend enumeration %r"
	% (class_name, base.__name__)
	)

	@staticmethod
	def _get_mixins_(class_name, bases):
	"""
	Returns the type for creating enum members, and the first inherited
	enum class.

	bases: the tuple of bases that was given to __new__
	"""
	if not bases:
	return object, Enum

	def _find_data_type(bases):
	data_types = set()
	for chain in bases:
	candidate = None
	for base in chain.__mro__:
	if base is object:
	continue
	elif issubclass(base, Enum):
	if base._member_type_ is not object:
	data_types.add(base._member_type_)
	break
	elif '__new__' in base.__dict__:
	if issubclass(base, Enum):
	continue
	data_types.add(candidate or base)
	break
	else:
	candidate = candidate or base
	if len(data_types) > 1:
	raise TypeError('%r: too many data types: %r' % (class_name, data_types))
	elif data_types:
	return data_types.pop()
	else:
	return None

	# ensure final parent class is an Enum derivative, find any concrete
	# data type, and check that Enum has no members
	first_enum = bases[-1]
	if not issubclass(first_enum, Enum):
	raise TypeError("new enumerations should be created as "
	"`EnumName([mixin_type, ...] [data_type,] enum_type)`")
	member_type = _find_data_type(bases) or object
	if first_enum._member_names_:
	raise TypeError("Cannot extend enumerations")
	return member_type, first_enum

	@staticmethod
	def _find_new_(classdict, member_type, first_enum):
	"""
	Returns the __new__ to be used for creating the enum members.

	classdict: the class dictionary given to __new__
	member_type: the data type whose __new__ will be used by default
	first_enum: enumeration to check for an overriding __new__
	"""
	# now find the correct __new__, checking to see of one was defined
	# by the user; also check earlier enum classes in case a __new__ was
	# saved as __new_member__
	__new__ = classdict.get('__new__', None)

	# should __new__ be saved as __new_member__ later?
	save_new = __new__ is not None

	if __new__ is None:
	# check all possibles for __new_member__ before falling back to
	# __new__
	for method in ('__new_member__', '__new__'):
	for possible in (member_type, first_enum):
	target = getattr(possible, method, None)
	if target not in {
	None,
	None.__new__,
	object.__new__,
	Enum.__new__,
	}:
	__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
	try:
	if isinstance(result, cls):
	return result
	else:
	ve_exc = ValueError("%r is not a valid %s" % (value, cls.__qualname__))
	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
	finally:
	# ensure all variables that could hold an exception are destroyed
	exc = None
	ve_exc = None

	def _generate_next_value_(name, start, count, last_values):
	"""
	Generate the next value when not given.

	name: the name of the member
	start: the initial start value or None
	count: the number of existing members
	last_value: the last value assigned or None
	"""
	for last_value in reversed(last_values):
	try:
	return last_value + 1
	except TypeError:
	pass
	else:
	return start

	@classmethod
	def _missing_(cls, value):
	return None

	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):
	"""
	Returns all members and all public methods
	"""
	added_behavior = [
	m
	for cls in self.__class__.mro()
	for m in cls.__dict__
	if m[0] != '_' and m not in self._member_map_
	] + [m for m in self.__dict__ if m[0] != '_']
	return (['__class__', '__doc__', '__module__'] + added_behavior)

	def __format__(self, format_spec):
	"""
	Returns format using actual value type unless __str__ has been overridden.
	"""
	# 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, or branch with __str__ explicitly overridden
	str_overridden = type(self).__str__ not in (Enum.__str__, Flag.__str__)
	if self._member_type_ is object or str_overridden:
	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_


	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 initial 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):
	"""
	Returns member (possibly creating it) if one can be found for 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.__qualname__))
	# 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):
	"""
	Returns True if self has at least the same flags set as other.
	"""
	if not isinstance(other, self.__class__):
	raise TypeError(
	"unsupported operand type(s) for 'in': '%s' and '%s'" % (
	type(other).__qualname__, self.__class__.__qualname__))
	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):
	"""
	Returns member (possibly creating it) if one can be found for value.
	"""
	if not isinstance(value, int):
	raise ValueError("%r is not a valid %s" % (value, cls.__qualname__))
	new_member = cls._create_pseudo_member_(value)
	return new_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:
	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
	members = []
	for member in flag:
	member_value = member.value
	if member_value and member_value & value == member_value:
	members.append(member)
	not_covered &= ~member_value
	if not negative:
	tmp = not_covered
	while tmp:
	flag_value = 2 ** _high_bit(tmp)
	if flag_value in flag._value2member_map_:
	members.append(flag._value2member_map_[flag_value])
	not_covered &= ~flag_value
	tmp &= ~flag_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

Jul	DEC	Jun
	29
2021	2022	2025