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Location: kallithea/rhodecode/lib/dbmigrate/migrate/versioning/util/keyedinstance.py - annotation
8ecc6b8229a5
1.1 KiB
text/x-python
commit less models
- models don't do any commits(with few exceptions)
- all db transactions should be handled by higher level modules like controllers, celery tasks
- models don't do any commits(with few exceptions)
- all db transactions should be handled by higher level modules like controllers, celery tasks
9753e0907827 9753e0907827 9753e0907827 9753e0907827 9753e0907827 9753e0907827 6832ef664673 9753e0907827 9753e0907827 9753e0907827 9753e0907827 9753e0907827 9753e0907827 9753e0907827 9753e0907827 9753e0907827 9753e0907827 9753e0907827 9753e0907827 9753e0907827 9753e0907827 9753e0907827 9753e0907827 9753e0907827 9753e0907827 9753e0907827 6832ef664673 9753e0907827 9753e0907827 9753e0907827 9753e0907827 9753e0907827 9753e0907827 9753e0907827 9753e0907827 9753e0907827 | #!/usr/bin/env python
# -*- coding: utf-8 -*-
class KeyedInstance(object):
"""A class whose instances have a unique identifier of some sort
No two instances with the same unique ID should exist - if we try to create
a second instance, the first should be returned.
"""
_instances = dict()
def __new__(cls, *p, **k):
instances = cls._instances
clskey = str(cls)
if clskey not in instances:
instances[clskey] = dict()
instances = instances[clskey]
key = cls._key(*p, **k)
if key not in instances:
instances[key] = super(KeyedInstance, cls).__new__(cls)
return instances[key]
@classmethod
def _key(cls, *p, **k):
"""Given a unique identifier, return a dictionary key
This should be overridden by child classes, to specify which parameters
should determine an object's uniqueness
"""
raise NotImplementedError()
@classmethod
def clear(cls):
# Allow cls.clear() as well as uniqueInstance.clear(cls)
if str(cls) in cls._instances:
del cls._instances[str(cls)]
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