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enum.py
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2197 lines (2012 loc) · 84.6 KB
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import sys
import builtins as bltns
from types import MappingProxyType, DynamicClassAttribute
__all__ = [
'EnumType', 'EnumMeta', 'EnumDict',
'Enum', 'IntEnum', 'StrEnum', 'Flag', 'IntFlag', 'ReprEnum',
'auto', 'unique', 'property', 'verify', 'member', 'nonmember',
'FlagBoundary', 'STRICT', 'CONFORM', 'EJECT', 'KEEP',
'global_flag_repr', 'global_enum_repr', 'global_str', 'global_enum',
'EnumCheck', 'CONTINUOUS', 'NAMED_FLAGS', 'UNIQUE',
'pickle_by_global_name', 'pickle_by_enum_name', 'show_flag_values',
'bin',
]
# Dummy value for Enum and Flag as there are explicit checks for them
# before they have been created.
# This is also why there are checks in EnumType like `if Enum is not None`
Enum = Flag = EJECT = ReprEnum = None
class nonmember(object):
"""
Protects item from becoming an Enum member during class creation.
"""
def __init__(self, value):
self.value = value
class member(object):
"""
Forces item to become an Enum member during class creation.
"""
def __init__(self, value):
self.value = value
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] != '_' and
name[-2] != '_'
)
def _is_internal_class(cls_name, obj):
# do not use `re` as `re` imports `enum`
if not isinstance(obj, type):
return False
qualname = getattr(obj, '__qualname__', '')
s_pattern = cls_name + '.' + getattr(obj, '__name__', '')
e_pattern = '.' + s_pattern
return qualname == s_pattern or qualname.endswith(e_pattern)
def _is_private(cls_name, name):
# do not use `re` as `re` imports `enum`
pattern = '_%s__' % (cls_name, )
pat_len = len(pattern)
if (
len(name) > pat_len
and name.startswith(pattern)
and (name[-1] != '_' or name[-2] != '_')
):
return True
else:
return False
def _is_single_bit(num):
"""
True if only one bit set in num (should be an int)
"""
if num == 0:
return False
num &= num - 1
return num == 0
def _make_class_unpicklable(obj):
"""
Make the given obj un-picklable.
obj should be either a dictionary, or an Enum
"""
def _break_on_call_reduce(self, proto):
raise TypeError('%r cannot be pickled' % self)
if isinstance(obj, dict):
obj['__reduce_ex__'] = _break_on_call_reduce
obj['__module__'] = '<unknown>'
else:
setattr(obj, '__reduce_ex__', _break_on_call_reduce)
setattr(obj, '__module__', '<unknown>')
def _iter_bits_lsb(num):
# num must be a positive integer
original = num
if isinstance(num, Enum):
num = num.value
if num < 0:
raise ValueError('%r is not a positive integer' % original)
while num:
b = num & (~num + 1)
yield b
num ^= b
def show_flag_values(value):
return list(_iter_bits_lsb(value))
def bin(num, max_bits=None):
"""
Like built-in bin(), except negative values are represented in
twos-complement, and the leading bit always indicates sign
(0=positive, 1=negative).
>>> bin(10)
'0b0 1010'
>>> bin(~10) # ~10 is -11
'0b1 0101'
"""
num = num.__index__()
ceiling = 2 ** (num).bit_length()
if num >= 0:
s = bltns.bin(num + ceiling).replace('1', '0', 1)
else:
s = bltns.bin(~num ^ (ceiling - 1) + ceiling)
sign = s[:3]
digits = s[3:]
if max_bits is not None:
if len(digits) < max_bits:
digits = (sign[-1] * max_bits + digits)[-max_bits:]
return "%s %s" % (sign, digits)
class _not_given:
def __repr__(self):
return('<not given>')
_not_given = _not_given()
class _auto_null:
def __repr__(self):
return '_auto_null'
_auto_null = _auto_null()
class auto:
"""
Instances are replaced with an appropriate value in Enum class suites.
"""
def __init__(self, value=_auto_null):
self.value = value
def __repr__(self):
return "auto(%r)" % self.value
class property(DynamicClassAttribute):
"""
This is a descriptor, used to define attributes that act differently
when accessed through an enum member and through an enum class.
Instance access is the same as property(), but access to an attribute
through the enum class will instead look in the class' _member_map_ for
a corresponding enum member.
"""
member = None
_attr_type = None
_cls_type = None
def __get__(self, instance, ownerclass=None):
if instance is None:
if self.member is not None:
return self.member
else:
raise AttributeError(
'%r has no attribute %r' % (ownerclass, self.name)
)
if self.fget is not None:
# use previous enum.property
return self.fget(instance)
elif self._attr_type == 'attr':
# look up previous attribute
return getattr(self._cls_type, self.name)
elif self._attr_type == 'desc':
# use previous descriptor
return getattr(instance._value_, self.name)
# look for a member by this name.
try:
return ownerclass._member_map_[self.name]
except KeyError:
raise AttributeError(
'%r has no attribute %r' % (ownerclass, self.name)
) from None
def __set__(self, instance, value):
if self.fset is not None:
return self.fset(instance, value)
raise AttributeError(
"<enum %r> cannot set attribute %r" % (self.clsname, self.name)
)
def __delete__(self, instance):
if self.fdel is not None:
return self.fdel(instance)
raise AttributeError(
"<enum %r> cannot delete attribute %r" % (self.clsname, self.name)
)
def __set_name__(self, ownerclass, name):
self.name = name
self.clsname = ownerclass.__name__
class _proto_member:
"""
intermediate step for enum members between class execution and final creation
"""
def __init__(self, value):
self.value = value
def __set_name__(self, enum_class, member_name):
"""
convert each quasi-member into an instance of the new enum class
"""
# first step: remove ourself from enum_class
delattr(enum_class, member_name)
# second step: create member based on enum_class
value = self.value
if not isinstance(value, tuple):
args = (value, )
else:
args = value
if enum_class._member_type_ is tuple: # special case for tuple enums
args = (args, ) # wrap it one more time
if not enum_class._use_args_:
enum_member = enum_class._new_member_(enum_class)
else:
enum_member = enum_class._new_member_(enum_class, *args)
if not hasattr(enum_member, '_value_'):
if enum_class._member_type_ is object:
enum_member._value_ = value
else:
try:
enum_member._value_ = enum_class._member_type_(*args)
except Exception as exc:
new_exc = TypeError(
'_value_ not set in __new__, unable to create it'
)
new_exc.__cause__ = exc
raise new_exc
value = enum_member._value_
enum_member._name_ = member_name
enum_member.__objclass__ = enum_class
enum_member.__init__(*args)
enum_member._sort_order_ = len(enum_class._member_names_)
if Flag is not None and issubclass(enum_class, Flag):
if isinstance(value, int):
enum_class._flag_mask_ |= value
if _is_single_bit(value):
enum_class._singles_mask_ |= value
enum_class._all_bits_ = 2 ** ((enum_class._flag_mask_).bit_length()) - 1
# If another member with the same value was already defined, the
# new member becomes an alias to the existing one.
try:
try:
# try to do a fast lookup to avoid the quadratic loop
enum_member = enum_class._value2member_map_[value]
except TypeError:
for name, canonical_member in enum_class._member_map_.items():
if canonical_member._value_ == value:
enum_member = canonical_member
break
else:
raise KeyError
except KeyError:
# this could still be an alias if the value is multi-bit and the
# class is a flag class
if (
Flag is None
or not issubclass(enum_class, Flag)
):
# no other instances found, record this member in _member_names_
enum_class._member_names_.append(member_name)
elif (
Flag is not None
and issubclass(enum_class, Flag)
and isinstance(value, int)
and _is_single_bit(value)
):
# no other instances found, record this member in _member_names_
enum_class._member_names_.append(member_name)
enum_class._add_member_(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_.setdefault(value, enum_member)
if value not in enum_class._hashable_values_:
enum_class._hashable_values_.append(value)
except TypeError:
# keep track of the value in a list so containment checks are quick
enum_class._unhashable_values_.append(value)
enum_class._unhashable_values_map_.setdefault(member_name, []).append(value)
class EnumDict(dict):
"""
Track enum member order and ensure member names are not reused.
EnumType will use the names found in self._member_names as the
enumeration member names.
"""
def __init__(self, cls_name=None):
super().__init__()
self._member_names = {} # use a dict -- faster look-up than a list, and keeps insertion order since 3.7
self._last_values = []
self._ignore = []
self._auto_called = False
self._cls_name = cls_name
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 self._cls_name is not None and _is_private(self._cls_name, key):
# do nothing, name will be a normal attribute
pass
elif _is_sunder(key):
if key not in (
'_order_',
'_generate_next_value_', '_numeric_repr_', '_missing_', '_ignore_',
'_iter_member_', '_iter_member_by_value_', '_iter_member_by_def_',
'_add_alias_', '_add_value_alias_',
# While not in use internally, those are common for pretty
# printing and thus excluded from Enum's reservation of
# _sunder_ names
) and not key.startswith('_repr_'):
raise ValueError(
'_sunder_ names, such as %r, are reserved for future Enum use'
% (key, )
)
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")
_gnv = value.__func__ if isinstance(value, staticmethod) else value
setattr(self, '_generate_next_value', _gnv)
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('%r already defined as %r' % (key, self[key]))
elif key in self._ignore:
pass
elif isinstance(value, nonmember):
# unwrap value here; it won't be processed by the below `else`
value = value.value
elif _is_descriptor(value):
pass
elif self._cls_name is not None and _is_internal_class(self._cls_name, value):
# do nothing, name will be a normal attribute
pass
else:
if key in self:
# enum overwriting a descriptor?
raise TypeError('%r already defined as %r' % (key, self[key]))
elif isinstance(value, member):
# unwrap value here -- it will become a member
value = value.value
non_auto_store = True
single = False
if isinstance(value, auto):
single = True
value = (value, )
if isinstance(value, tuple) and any(isinstance(v, auto) for v in value):
# insist on an actual tuple, no subclasses, in keeping with only supporting
# top-level auto() usage (not contained in any other data structure)
auto_valued = []
t = type(value)
for v in value:
if isinstance(v, auto):
non_auto_store = False
if v.value == _auto_null:
v.value = self._generate_next_value(
key, 1, len(self._member_names), self._last_values[:],
)
self._auto_called = True
v = v.value
self._last_values.append(v)
auto_valued.append(v)
if single:
value = auto_valued[0]
else:
try:
# accepts iterable as multiple arguments?
value = t(auto_valued)
except TypeError:
# then pass them in singly
value = t(*auto_valued)
self._member_names[key] = None
if non_auto_store:
self._last_values.append(value)
super().__setitem__(key, value)
@property
def member_names(self):
return list(self._member_names)
def update(self, members, **more_members):
try:
for name in members.keys():
self[name] = members[name]
except AttributeError:
for name, value in members:
self[name] = value
for name, value in more_members.items():
self[name] = value
_EnumDict = EnumDict # keep private name for backwards compatibility
class EnumType(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(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, *, boundary=None, _simple=False, **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).
#
if _simple:
return super().__new__(metacls, cls, bases, classdict, **kwds)
#
# remove any keys listed in _ignore_
classdict.setdefault('_ignore_', []).append('_ignore_')
ignore = classdict['_ignore_']
for key in ignore:
classdict.pop(key, None)
#
# grab member names
member_names = classdict._member_names
#
# check for illegal enum names (any others?)
invalid_names = set(member_names) & {'mro', ''}
if invalid_names:
raise ValueError('invalid enum member name(s) %s' % (
','.join(repr(n) for n in invalid_names)
))
#
# adjust the sunders
_order_ = classdict.pop('_order_', None)
_gnv = classdict.get('_generate_next_value_')
if _gnv is not None and type(_gnv) is not staticmethod:
_gnv = staticmethod(_gnv)
# convert to normal dict
classdict = dict(classdict.items())
if _gnv is not None:
classdict['_generate_next_value_'] = _gnv
#
# data type of member and the controlling Enum class
member_type, first_enum = metacls._get_mixins_(cls, bases)
__new__, save_new, use_args = metacls._find_new_(
classdict, member_type, first_enum,
)
classdict['_new_member_'] = __new__
classdict['_use_args_'] = use_args
#
# convert future enum members into temporary _proto_members
for name in member_names:
value = classdict[name]
classdict[name] = _proto_member(value)
#
# house-keeping structures
classdict['_member_names_'] = []
classdict['_member_map_'] = {}
classdict['_value2member_map_'] = {}
classdict['_hashable_values_'] = [] # for comparing with non-hashable types
classdict['_unhashable_values_'] = [] # e.g. frozenset() with set()
classdict['_unhashable_values_map_'] = {}
classdict['_member_type_'] = member_type
# now set the __repr__ for the value
classdict['_value_repr_'] = metacls._find_data_repr_(cls, bases)
#
# Flag structures (will be removed if final class is not a Flag)
classdict['_boundary_'] = (
boundary
or getattr(first_enum, '_boundary_', None)
)
classdict['_flag_mask_'] = 0
classdict['_singles_mask_'] = 0
classdict['_all_bits_'] = 0
classdict['_inverted_'] = None
# check for negative flag values and invert if found (using _proto_members)
if Flag is not None and bases and issubclass(bases[-1], Flag):
bits = 0
inverted = []
for n in member_names:
p = classdict[n]
if isinstance(p.value, int):
if p.value < 0:
inverted.append(p)
else:
bits |= p.value
elif p.value is None:
pass
elif isinstance(p.value, tuple) and p.value and isinstance(p.value[0], int):
if p.value[0] < 0:
inverted.append(p)
else:
bits |= p.value[0]
for p in inverted:
if isinstance(p.value, int):
p.value = bits & p.value
else:
p.value = (bits & p.value[0], ) + p.value[1:]
try:
classdict['_%s__in_progress' % cls] = True
enum_class = super().__new__(metacls, cls, bases, classdict, **kwds)
classdict['_%s__in_progress' % cls] = False
delattr(enum_class, '_%s__in_progress' % cls)
except Exception as e:
# since 3.12 the note "Error calling __set_name__ on '_proto_member' instance ..."
# is tacked on to the error instead of raising a RuntimeError, so discard it
if hasattr(e, '__notes__'):
del e.__notes__
raise
# update classdict with any changes made by __init_subclass__
classdict.update(enum_class.__dict__)
#
# 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
#
# Also, special handling for ReprEnum
if ReprEnum is not None and ReprEnum in bases:
if member_type is object:
raise TypeError(
'ReprEnum subclasses must be mixed with a data type (i.e.'
' int, str, float, etc.)'
)
if '__format__' not in classdict:
enum_class.__format__ = member_type.__format__
classdict['__format__'] = enum_class.__format__
if '__str__' not in classdict:
method = member_type.__str__
if method is object.__str__:
# if member_type does not define __str__, object.__str__ will use
# its __repr__ instead, so we'll also use its __repr__
method = member_type.__repr__
enum_class.__str__ = method
classdict['__str__'] = enum_class.__str__
for name in ('__repr__', '__str__', '__format__', '__reduce_ex__'):
if name not in classdict:
# check for mixin overrides before replacing
enum_method = getattr(first_enum, name)
found_method = getattr(enum_class, name)
object_method = getattr(object, name)
data_type_method = getattr(member_type, name)
if found_method in (data_type_method, object_method):
setattr(enum_class, name, enum_method)
#
# for Flag, add __or__, __and__, __xor__, and __invert__
if Flag is not None and issubclass(enum_class, Flag):
for name in (
'__or__', '__and__', '__xor__',
'__ror__', '__rand__', '__rxor__',
'__invert__'
):
if name not in classdict:
enum_method = getattr(Flag, name)
setattr(enum_class, name, enum_method)
classdict[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)
#
# _order_ checking is spread out into three/four steps
# - if enum_class is a Flag:
# - remove any non-single-bit flags from _order_
# - remove any aliases from _order_
# - check that _order_ and _member_names_ match
#
# step 1: ensure we have a list
if _order_ is not None:
if isinstance(_order_, str):
_order_ = _order_.replace(',', ' ').split()
#
# remove Flag structures if final class is not a Flag
if (
Flag is None and cls != 'Flag'
or Flag is not None and not issubclass(enum_class, Flag)
):
delattr(enum_class, '_boundary_')
delattr(enum_class, '_flag_mask_')
delattr(enum_class, '_singles_mask_')
delattr(enum_class, '_all_bits_')
delattr(enum_class, '_inverted_')
elif Flag is not None and issubclass(enum_class, Flag):
# set correct __iter__
member_list = [m._value_ for m in enum_class]
if member_list != sorted(member_list):
enum_class._iter_member_ = enum_class._iter_member_by_def_
if _order_:
# _order_ step 2: remove any items from _order_ that are not single-bit
_order_ = [
o
for o in _order_
if o not in enum_class._member_map_ or _is_single_bit(enum_class[o]._value_)
]
#
if _order_:
# _order_ step 3: remove aliases from _order_
_order_ = [
o
for o in _order_
if (
o not in enum_class._member_map_
or
(o in enum_class._member_map_ and o in enum_class._member_names_)
)]
# _order_ step 4: verify that _order_ and _member_names_ match
if _order_ != enum_class._member_names_:
raise TypeError(
'member order does not match _order_:\n %r\n %r'
% (enum_class._member_names_, _order_)
)
#
return enum_class
def __bool__(cls):
"""
classes/types should always be True.
"""
return True
def __call__(cls, value, names=_not_given, *values, module=None, qualname=None, type=None, start=1, boundary=None):
"""
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')).
The value lookup branch is chosen if the enum is final.
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 cls._member_map_:
# simple value lookup if members exist
if names is not _not_given:
value = (value, names) + values
return cls.__new__(cls, value)
# otherwise, functional API: we're creating a new Enum type
if names is _not_given and type is None:
# no body? no data-type? possibly wrong usage
raise TypeError(
f"{cls} has no members; specify `names=()` if you meant to create a new, empty, enum"
)
return cls._create_(
class_name=value,
names=None if names is _not_given else names,
module=module,
qualname=qualname,
type=type,
start=start,
boundary=boundary,
)
def __contains__(cls, value):
"""Return True if `value` is in `cls`.
`value` is in `cls` if:
1) `value` is a member of `cls`, or
2) `value` is the value of one of the `cls`'s members.
3) `value` is a pseudo-member (flags)
"""
if isinstance(value, cls):
return True
if issubclass(cls, Flag):
try:
result = cls._missing_(value)
return isinstance(result, cls)
except ValueError:
pass
return (
value in cls._unhashable_values_ # both structures are lists
or value in cls._hashable_values_
)
def __delattr__(cls, attr):
# nicer error message when someone tries to delete an attribute
# (see issue19025).
if attr in cls._member_map_:
raise AttributeError("%r cannot delete member %r." % (cls.__name__, attr))
super().__delattr__(attr)
def __dir__(cls):
if issubclass(cls, Flag):
members = list(cls._member_map_.keys())
else:
members = cls._member_names_
interesting = set([
'__class__', '__contains__', '__doc__', '__getitem__',
'__iter__', '__len__', '__members__', '__module__',
'__name__', '__qualname__',
]
+ members
)
if cls._new_member_ is not object.__new__:
interesting.add('__new__')
if cls.__init_subclass__ is not object.__init_subclass__:
interesting.add('__init_subclass__')
if cls._member_type_ is object:
return sorted(interesting)
else:
# return whatever mixed-in data type has
return sorted(set(dir(cls._member_type_)) | interesting)
def __getitem__(cls, name):
"""
Return the member matching `name`.
"""
return cls._member_map_[name]
def __iter__(cls):
"""
Return members in definition order.
"""
return (cls._member_map_[name] for name in cls._member_names_)
def __len__(cls):
"""
Return the number of members (no aliases)
"""
return len(cls._member_names_)
@bltns.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):
if Flag is not None and issubclass(cls, Flag):
return "<flag %r>" % cls.__name__
else:
return "<enum %r>" % cls.__name__
def __reversed__(cls):
"""
Return 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 member %r' % (name, ))
super().__setattr__(name, value)
def _create_(cls, class_name, names, *, module=None, qualname=None, type=None, start=1, boundary=None):
"""
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_(class_name, 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))
if names is None:
names = ()
# 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
if module is None:
try:
module = sys._getframemodulename(2)
except AttributeError:
# Fall back on _getframe if _getframemodulename is missing
try:
module = sys._getframe(2).f_globals['__name__']
except (AttributeError, ValueError, KeyError):
pass
if module is None:
_make_class_unpicklable(classdict)
else:
classdict['__module__'] = module
if qualname is not None:
classdict['__qualname__'] = qualname
return metacls.__new__(metacls, class_name, bases, classdict, boundary=boundary)
def _convert_(cls, name, module, filter, source=None, *, boundary=None, as_global=False):
"""
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 = sys.modules[module].__dict__
if source:
source = source.__dict__
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])
body = {t[0]: t[1] for t in members}
body['__module__'] = module
tmp_cls = type(name, (object, ), body)
cls = _simple_enum(etype=cls, boundary=boundary or KEEP)(tmp_cls)
if as_global:
global_enum(cls)
else:
sys.modules[cls.__module__].__dict__.update(cls.__members__)
module_globals[name] = cls
return cls
@classmethod
def _check_for_existing_members_(mcls, class_name, bases):
for chain in bases:
for base in chain.__mro__:
if isinstance(base, EnumType) and base._member_names_:
raise TypeError(
"<enum %r> cannot extend %r"
% (class_name, base)
)
@classmethod
def _get_mixins_(mcls, 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
# 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 isinstance(first_enum, EnumType):
raise TypeError("new enumerations should be created as "
"`EnumName([mixin_type, ...] [data_type,] enum_type)`")
member_type = mcls._find_data_type_(class_name, bases) or object
return member_type, first_enum
@classmethod
def _find_data_repr_(mcls, class_name, bases):
for chain in bases:
for base in chain.__mro__:
if base is object:
continue
elif isinstance(base, EnumType):
# if we hit an Enum, use it's _value_repr_
return base._value_repr_
elif '__repr__' in base.__dict__:
# this is our data repr
# double-check if a dataclass with a default __repr__
if (
'__dataclass_fields__' in base.__dict__
and '__dataclass_params__' in base.__dict__
and base.__dict__['__dataclass_params__'].repr
):
return _dataclass_repr
else:
return base.__dict__['__repr__']
return None
@classmethod
def _find_data_type_(mcls, class_name, bases):
# a datatype has a __new__ method, or a __dataclass_fields__ attribute
data_types = set()