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5166097d7c
Enumeration helpers are callables, so the template system tried to call them with no arguments. Thanks Rupert Baker for helping discover this.
83 lines
2.7 KiB
Python
83 lines
2.7 KiB
Python
import enum
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from django.utils.functional import Promise
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__all__ = ['Choices', 'IntegerChoices', 'TextChoices']
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class ChoicesMeta(enum.EnumMeta):
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"""A metaclass for creating a enum choices."""
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def __new__(metacls, classname, bases, classdict):
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labels = []
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for key in classdict._member_names:
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value = classdict[key]
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if (
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isinstance(value, (list, tuple)) and
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len(value) > 1 and
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isinstance(value[-1], (Promise, str))
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):
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*value, label = value
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value = tuple(value)
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else:
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label = key.replace('_', ' ').title()
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labels.append(label)
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# Use dict.__setitem__() to suppress defenses against double
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# assignment in enum's classdict.
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dict.__setitem__(classdict, key, value)
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cls = super().__new__(metacls, classname, bases, classdict)
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cls._value2label_map_ = dict(zip(cls._value2member_map_, labels))
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# Add a label property to instances of enum which uses the enum member
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# that is passed in as "self" as the value to use when looking up the
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# label in the choices.
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cls.label = property(lambda self: cls._value2label_map_.get(self.value))
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cls.do_not_call_in_templates = True
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return enum.unique(cls)
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def __contains__(cls, member):
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if not isinstance(member, enum.Enum):
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# Allow non-enums to match against member values.
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return any(x.value == member for x in cls)
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return super().__contains__(member)
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@property
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def names(cls):
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empty = ['__empty__'] if hasattr(cls, '__empty__') else []
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return empty + [member.name for member in cls]
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@property
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def choices(cls):
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empty = [(None, cls.__empty__)] if hasattr(cls, '__empty__') else []
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return empty + [(member.value, member.label) for member in cls]
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@property
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def labels(cls):
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return [label for _, label in cls.choices]
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@property
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def values(cls):
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return [value for value, _ in cls.choices]
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class Choices(enum.Enum, metaclass=ChoicesMeta):
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"""Class for creating enumerated choices."""
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def __str__(self):
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"""
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Use value when cast to str, so that Choices set as model instance
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attributes are rendered as expected in templates and similar contexts.
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"""
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return str(self.value)
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class IntegerChoices(int, Choices):
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"""Class for creating enumerated integer choices."""
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pass
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class TextChoices(str, Choices):
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"""Class for creating enumerated string choices."""
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def _generate_next_value_(name, start, count, last_values):
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return name
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