gistfile1.py

from functools import wraps
from django.conf import settings


class cached_property(object):
    """A read-only @property that is only evaluated once. The value is cached
    on the object itself rather than the function or class; this should prevent
    memory leakage."""
    def __init__(self, fget, doc=None):
        self.fget = fget
        self.__doc__ = doc or fget.__doc__
        self.__name__ = fget.__name__
        self.__module__ = fget.__module__

    def __get__(self, obj, cls):
        if obj is None:
            return self
        result = self.fget(obj)
        if settings.ENABLE_CACHED_PROPERTY:
            obj.__dict__[self.__name__] = result
        return result