bazarr/libs/playhouse/hybrid.py

51 lines
1.4 KiB
Python

# Hybrid methods/attributes, based on similar functionality in SQLAlchemy:
# http://docs.sqlalchemy.org/en/improve_toc/orm/extensions/hybrid.html
class hybrid_method(object):
def __init__(self, func, expr=None):
self.func = func
self.expr = expr or func
def __get__(self, instance, instance_type):
if instance is None:
return self.expr.__get__(instance_type, instance_type.__class__)
return self.func.__get__(instance, instance_type)
def expression(self, expr):
self.expr = expr
return self
class hybrid_property(object):
def __init__(self, fget, fset=None, fdel=None, expr=None):
self.fget = fget
self.fset = fset
self.fdel = fdel
self.expr = expr or fget
def __get__(self, instance, instance_type):
if instance is None:
return self.expr(instance_type)
return self.fget(instance)
def __set__(self, instance, value):
if self.fset is None:
raise AttributeError('Cannot set attribute.')
self.fset(instance, value)
def __delete__(self, instance):
if self.fdel is None:
raise AttributeError('Cannot delete attribute.')
self.fdel(instance)
def setter(self, fset):
self.fset = fset
return self
def deleter(self, fdel):
self.fdel = fdel
return self
def expression(self, expr):
self.expr = expr
return self