terminator/terminatorlib/borg.py

108 lines
3.0 KiB
Python
Raw Normal View History

#!/usr/bin/python
# Terminator by Chris Jones <cmsj@tenshu.net>
# GPL v2 only
"""borg.py - We are the borg. Resistance is futile.
http://code.activestate.com/recipes/66531/
ActiveState's policy appears to be that snippets
exist to encourage re-use, but I can not find any
specific licencing terms.
>>> obj1 = TestBorg()
>>> obj2 = TestBorg()
>>> obj1.attribute
0
>>> obj2.attribute
0
>>> obj1.attribute = 12345
>>> obj1.attribute
12345
>>> obj2.attribute
12345
>>> obj2.attribute = 54321
>>> obj1.attribute
54321
>>> obj3 = TestBorg2()
>>> obj3.attribute
1
>>> obj4 = TestBorg2()
>>> obj3.attribute = 98765
>>> obj4.attribute
98765
>>>
"""
from util import dbg
2009-08-11 22:23:34 +00:00
# pylint: disable-msg=R0903
2009-12-09 13:22:34 +00:00
# pylint: disable-msg=R0921
class Borg:
2009-10-09 11:25:06 +00:00
"""Definition of a class that can never be duplicated. Correct usage is
thus:
from borg import Borg
class foo(Borg):
# All attributes on a borg class *must* = None
attribute = None
def __init__(self):
Borg.__init__(self, self.__class__.__name__)
2009-10-09 11:25:06 +00:00
def prepare_attributes(self):
if not self.attribute:
self.attribute = []
bar = foo()
bar.prepare_attributes()
The important thing to note is that all attributes of borg classes *must* be
declared as being None. If you attempt to use static class attributes you
will get unpredicted behaviour. Instead, prepare_attributes() must be called
which will then see the attributes in the shared state, and initialise them
if necessary."""
__shared_state = {}
2009-10-09 11:25:06 +00:00
def __init__(self, borgtype=None):
2009-10-09 11:25:06 +00:00
"""Class initialiser. Overwrite our class dictionary with the shared
state. This makes us identical to every other instance of this class
type."""
if borgtype is None:
raise TypeError('Borg::__init__: You must pass a borgtype')
if not self.__shared_state.has_key(borgtype):
dbg('Borg::__init__: Preparing borg state for %s' % borgtype)
self.__shared_state[borgtype] = {}
self.__dict__ = self.__shared_state[borgtype]
2009-10-09 11:25:06 +00:00
def prepare_attributes(self):
"""This should be used to prepare any attributes of the borg class."""
raise NotImplementedError('prepare_attributes')
if __name__ == '__main__':
class TestBorg(Borg):
attribute = None
def __init__(self):
Borg.__init__(self, self.__class__.__name__)
self.prepare_attributes()
def prepare_attributes(self):
if not self.attribute:
self.attribute = 0
class TestBorg2(Borg):
attribute = None
def __init__(self):
Borg.__init__(self, self.__class__.__name__)
self.prepare_attributes()
def prepare_attributes(self):
if not self.attribute:
self.attribute = 1
import sys
import doctest
(failed, attempted) = doctest.testmod()
print "%d/%d tests failed" % (failed, attempted)
sys.exit(failed)