##############################################################################
#
# Copyright (c) 2003-2009 Zope Foundation and Contributors.
# All Rights Reserved.
#
# This software is subject to the provisions of the Zope Public License,
# Version 2.1 (ZPL). A copy of the ZPL should accompany this distribution.
# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
# FOR A PARTICULAR PURPOSE.
#
##############################################################################
"""Location support
"""
__docformat__ = 'restructuredtext'
from zope.interface import implementer
from zope.proxy import ProxyBase
from zope.proxy import getProxiedObject
from zope.proxy import non_overridable
from zope.proxy.decorator import DecoratorSpecificationDescriptor
from zope.location.interfaces import ILocation
[docs]
@implementer(ILocation)
class Location:
"""Mix-in that implements ILocation.
It provides the `__parent__` and `__name__` attributes.
"""
__parent__ = None
__name__ = None
[docs]
def locate(obj, parent, name=None):
"""Update a location's coordinates."""
obj.__parent__ = parent
obj.__name__ = name
[docs]
def located(obj, parent, name=None):
"""Ensure and return the location of an object.
Updates the location's coordinates.
"""
location = ILocation(obj)
locate(location, parent, name)
return location
[docs]
def LocationIterator(object):
"""Iterate over an object and all of its parents."""
while object is not None:
yield object
object = getattr(object, '__parent__', None)
[docs]
def inside(l1, l2):
"""Test whether l1 is a successor of l2.
l1 is a successor of l2 if l2 is in the chain of parents of l1 or l2
is l1.
"""
while l1 is not None:
if l1 is l2:
return True
l1 = getattr(l1, '__parent__', None)
return False
class ClassAndInstanceDescr:
def __init__(self, *args):
self.funcs = args
def __get__(self, inst, cls):
if inst is None:
return self.funcs[1](cls)
return self.funcs[0](inst)
[docs]
@implementer(ILocation)
class LocationProxy(ProxyBase):
"""Location-object proxy
This is a non-picklable proxy that can be put around objects that
don't implement `ILocation`.
"""
__slots__ = ('__parent__', '__name__')
__safe_for_unpickling__ = True
__doc__ = ClassAndInstanceDescr(
lambda inst: getProxiedObject(inst).__doc__,
lambda cls, __doc__=__doc__: __doc__,
)
def __new__(self, ob, container=None, name=None):
return ProxyBase.__new__(self, ob)
def __init__(self, ob, container=None, name=None):
ProxyBase.__init__(self, ob)
self.__parent__ = container
self.__name__ = name
def __getattribute__(self, name):
if name in LocationProxy.__dict__:
return object.__getattribute__(self, name)
return ProxyBase.__getattribute__(self, name)
def __setattr__(self, name, value):
if name in self.__slots__ + getattr(ProxyBase, '__slots__', ()):
# ('_wrapped', '__parent__', '__name__'):
try:
return object.__setattr__(self, name, value)
except TypeError: # pragma NO COVER C Optimization
return ProxyBase.__setattr__(self, name, value)
return ProxyBase.__setattr__(self, name, value)
@non_overridable
def __reduce__(self, proto=None):
raise TypeError("Not picklable")
__reduce_ex__ = __reduce__
__providedBy__ = DecoratorSpecificationDescriptor()