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"""Utilities for conditionally proxying method access to another class.""" |
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import typing |
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from . import _attribute_constructor |
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_T = typing.TypeVar("_T") |
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8
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9
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10
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class ConditionalMethod(typing.Generic[_T]): |
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"""Based on the value of the given attribute, forwards to the superclass or the source class.""" |
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name: str |
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__objclass__: typing.Type[_T] |
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def __init__(self, source: typing.Type[_T], field_check: str): |
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self.source = source |
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self.field_check = field_check |
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def __set_name__(self, owner, name): |
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self.__objclass__ = owner |
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self.name = name |
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def __get__(self, instance, owner): |
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if getattr(owner, self.field_check): |
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return getattr(self.source, self.name).__get__(instance, owner) |
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target = owner if instance is None else instance |
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return getattr(super(self.__objclass__, target), self.name) |
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def __set__(self, instance, value): |
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# Don't care about this coverage |
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raise AttributeError # pragma: nocover |
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def __delete__(self, instance): |
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# Don't care about this coverage |
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raise AttributeError # pragma: nocover |
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39
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def _manual_partial(source: typing.Type[_T]): |
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def wrapped(field_check: str): |
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return ConditionalMethod(source, field_check) |
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return wrapped |
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46
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def conditional_method( |
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source: typing.Type[_T] |
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) -> _attribute_constructor.AttributeConstructor[ConditionalMethod[_T]]: |
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"""Given a source class, return an attribute constructor that makes ConditionalMethods |
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It is not recommended to reuse the return value of this function. |
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""" |
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return _attribute_constructor.AttributeConstructor(_manual_partial(source)) |
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mwchase /
python-structured-data
