[ipfire.org.git] / src / backend / decorators.py

#!/usr/bin/python3

class Missing(object):
	pass

_missing = Missing()

class lazy_property(property):
	"""
		The property is only computed once and then being
		cached until the end of the lifetime of the object.
	"""
	def __init__(self, fget, fset=None, fdel=None, doc=None, name=None):
		property.__init__(self, fget=fget, fset=fset, fdel=fdel, doc=doc)

		self.__name__   = name or fget.__name__
		self.__module__ = fget.__module__

	def __get__(self, obj, type=None):
		if object is None:
			return self

		value = obj.__dict__.get(self.__name__, _missing)
		if value is _missing:
			obj.__dict__[self.__name__] = value = self.fget(obj)

		return value

	def __set__(self, obj, value):
		if self.fset:
			self.fset(obj, value)

		obj.__dict__[self.__name__] = value
Commit	Line	Data
de9dc716 MT	1	#!/usr/bin/python3
	2
	3	class Missing(object):
	4	pass
	5
	6	_missing = Missing()
	7
	8	class lazy_property(property):
	9	"""
	10	The property is only computed once and then being
	11	cached until the end of the lifetime of the object.
	12	"""
	13	def __init__(self, fget, fset=None, fdel=None, doc=None, name=None):
	14	property.__init__(self, fget=fget, fset=fset, fdel=fdel, doc=doc)
	15
	16	self.__name__ = name or fget.__name__
	17	self.__module__ = fget.__module__
	18
	19	def __get__(self, obj, type=None):
	20	if object is None:
	21	return self
	22
	23	value = obj.__dict__.get(self.__name__, _missing)
	24	if value is _missing:
	25	obj.__dict__[self.__name__] = value = self.fget(obj)
	26
	27	return value
	28
	29	def __set__(self, obj, value):
	30	if self.fset:
	31	self.fset(obj, value)
	32
	33	obj.__dict__[self.__name__] = value