add transaction.py
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static/files/transaction.py
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203
static/files/transaction.py
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# This program is free software; you can redistribute it and/or
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# modify it under the terms of the GNU Lesser General Public
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# License as published by the Free Software Foundation; either
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# version 2.1 of the License, or (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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# Lesser General Public License for more details.
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#
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# You should have received a copy of the GNU Lesser General Public
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# License along with this program; if not, write to the
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# Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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# Boston, MA 02111-1307, USA.
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"""
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Transactions of attributes by inheriting the Transaction class
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Basic Usage:
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class Test(Transaction):
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pass
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a = Test()
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a.test = "old state"
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a.commit()
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a.test = "bad state, roll me back"
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a.rollback()
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assert(a.test == "old state")
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See also: https://harald.hoyer.xyz/2015/10/13/a-python-transaction-class/
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Copyright (C) 2008 Harald Hoyer <harald@redhat.com>
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Copyright (C) 2008 Red Hat, Inc.
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"""
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import copy
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def _checksetseen(what, seen):
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"checks and sets the obj id in seen"
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if what in seen:
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return True
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seen.add(what)
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return False
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class Transaction(object):
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"""
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This class allows sub-classes to commit changes to an instance to a
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history, and rollback to previous states.
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Because the class only stores attributes in self.__dict__ sub-classes
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need to use the methods __getstate__ and __setstate__ to provide additional
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state information. See the Transactionlist below for an example usage.
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"""
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def commit(self, **kwargs):
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"""
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Commit the object state.
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If the optional argument "deep" is set to False,
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objects of class Transaction stored in this object will
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not be committed.
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"""
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seen = kwargs.get("_commit_seen", set())
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if _checksetseen(id(self), seen):
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return
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deep = kwargs.get("deep", True)
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# Do not deepcopy the Transaction objects. We want to keep the
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# reference. Instead commit() them.
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state = dict()
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for key, val in self.__dict__.items():
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if isinstance(val, Transaction):
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state[key] = val
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if deep:
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val.commit(_commit_seen=seen)
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elif key == "__l":
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# do not deepcopy our old state
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state[key] = val
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else:
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state[key] = copy.deepcopy(val)
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if hasattr(self, "__getstate__"):
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state = (state, getattr(self, "__getstate__")())
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self.__dict__["__l"] = state
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def rollback(self, **kwargs):
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"""
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Rollback the last committed object state.
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If the optional argument "deep" is set to False,
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objects of class Transaction stored in this object will
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not be rolled back.
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"""
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seen = kwargs.get("_rollback_seen", set())
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if _checksetseen(id(self), seen):
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return
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deep = kwargs.get("deep", True)
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state = None
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extrastate = None
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gotstate = False
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gotextrastate = False
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if "__l" in self.__dict__:
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state = self.__dict__["__l"]
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gotstate = True
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if type(state) is tuple:
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gotextrastate = True
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(state, extrastate) = state
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# rollback our childs, then ourselves
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for child in self.__dict__.values():
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if isinstance(child, Transaction):
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if deep:
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child.rollback(_rollback_seen=seen)
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if gotstate:
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self.__dict__.clear()
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self.__dict__.update(state)
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if gotextrastate and hasattr(self, "__setstate__"):
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getattr(self, "__setstate__")(extrastate)
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class Transactionlist(list, Transaction):
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"""
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An example subclass of list, which inherits transactions.
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Due to the special list implementation, we need the
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__getstate__ and __setstate__ methods.
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See the code for the implementation.
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"""
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def commit(self, **kwargs):
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"""
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Commit the object state.
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If the optional argument "deep" is set to False,
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objects of class Transaction stored in this object will
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not be committed.
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"""
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# make a local copy of the recursive marker
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seen = set(kwargs.get("_commit_seen", set()))
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super(Transactionlist, self).commit(**kwargs)
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if _checksetseen(id(self), seen):
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return
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deep = kwargs.get("deep", True)
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if deep:
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for val in self:
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if isinstance(val, Transaction):
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val.commit()
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def rollback(self, **kwargs):
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"""
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Rollback the last committed object state.
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If the optional argument "deep" is set to False,
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objects of class Transaction stored in this object will
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not be rolled back.
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"""
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# make a local copy of the recursive marker
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seen = set(kwargs.get("_rollback_seen", set()))
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super(Transactionlist, self).rollback(**kwargs)
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if _checksetseen(id(self), seen):
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return
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deep = kwargs.get("deep", True)
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if deep:
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for val in self:
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if isinstance(val, Transaction):
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val.rollback()
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def __getstate__(self):
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"""
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return a deepcopy of all non Transaction class objects in our list,
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and a reference for the committed Transaction objects.
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"""
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state = []
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for val in self:
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if isinstance(val, Transaction):
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state.append(val)
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else:
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state.append(copy.deepcopy(val))
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return state
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def __setstate__(self, state):
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"clear the list and restore all objects from the state"
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del self[:]
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self.extend(state)
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__author__ = "Harald Hoyer <harald@redhat.com>"
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454
static/files/transaction_test.py
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454
static/files/transaction_test.py
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@ -0,0 +1,454 @@
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# This program is free software; you can redistribute it and/or
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# modify it under the terms of the GNU Lesser General Public
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# License as published by the Free Software Foundation; either
|
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# version 2.1 of the License, or (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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# Lesser General Public License for more details.
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#
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# You should have received a copy of the GNU Lesser General Public
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# License along with this program; if not, write to the
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# Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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# Boston, MA 02111-1307, USA.
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"""\
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UnitTests for the Transaction class
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See also: https://harald.hoyer.xyz/2015/10/13/a-python-transaction-class/
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Copyright (C) 2008 Harald Hoyer <harald@redhat.com>
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Copyright (C) 2008 Red Hat, Inc.
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"""
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import unittest
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import sys
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import copy
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from transaction import Transaction
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class TransactionOld1(object):
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"""\
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Old Transaction class from
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http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/284677
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"""
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def __init__(self):
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self.log = []
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def commit(self, **kwargs):
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self.log.append(self.__dict__.copy())
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def rollback(self, **kwargs):
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try:
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self.__dict__.update(self.log.pop(-1))
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except IndexError:
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pass
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def __repr__(self):
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return "'self.__dict__ = %s'" % self.__dict__
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class TransactionOld2(TransactionOld1):
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def commit(self, **kwargs):
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self.log.append(copy.deepcopy(self.__dict__))
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class TransactionOld3(TransactionOld2):
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def rollback(self, **kwargs):
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try:
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state = self.log.pop(-1)
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self.__dict__.clear()
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self.__dict__.update(state)
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except IndexError:
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pass
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class TransactionNew1(object):
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def _docommit(self):
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if "log" not in self.__dict__:
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self.__dict__["log"] = list()
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self.__dict__["log"].append(copy.deepcopy(self.__dict__))
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def _dorollback(self):
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if "log" not in self.__dict__:
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return
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try:
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state = self.__dict__["log"].pop(-1)
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self.__dict__.clear()
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self.__dict__.update(state)
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except IndexError:
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pass
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def commit(self, **kwargs):
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# commit ourselves, then our childs
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self._docommit()
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if kwargs.get("deep", True):
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for child in self.__dict__.values():
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if isinstance(child, self.__class__):
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child.commit()
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def rollback(self, **kwargs):
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# rollback our childs, then ourselves
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if kwargs.get("deep", True):
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for child in self.__dict__.values():
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if isinstance(child, self.__class__):
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child.rollback()
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self._dorollback()
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def __repr__(self):
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return "'self.__dict__ = %s'" % self.__dict__
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class TransactionNew2(TransactionNew1):
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def _docommit(self):
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if "log" in self.__dict__:
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oldstate = self.__dict__.pop("log")
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else:
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oldstate = None
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state = copy.deepcopy(self.__dict__)
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if oldstate:
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state["log"] = oldstate
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self.__dict__["log"] = state
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def _dorollback(self):
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if "log" not in self.__dict__:
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return
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try:
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state = self.__dict__["log"]
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self.__dict__.clear()
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self.__dict__.update(state)
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except IndexError:
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pass
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def __repr__(self):
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return "'self.__dict__ = %s'" % self.__dict__
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class TransactionNew3(TransactionNew2):
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def _checksetseen(self, seen):
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if id(self) in seen:
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sys.stderr.write("Recursion detected... ")
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return True
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seen.add(id(self))
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return False
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def commit(self, **kwargs): # pylint: disable-msg=W0613
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seen = kwargs.get("_commit_seen", set())
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if self._checksetseen(seen):
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return
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# commit ourselves, then our childs
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self._docommit()
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if kwargs.get("deep", True):
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for child in self.__dict__.values():
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if isinstance(child, self.__class__):
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child.commit(_commit_seen=seen)
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def rollback(self, **kwargs):
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seen = kwargs.get("_rollback_seen", set())
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if self._checksetseen(seen):
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return
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# rollback our childs, then ourselves
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if kwargs.get("deep", True):
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for child in self.__dict__.values():
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if isinstance(child, self.__class__):
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child.rollback(_rollback_seen=seen)
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self._dorollback()
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class TransactionImproved(Transaction):
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def __repr__(self):
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return "'self.__dict__ = %s'" % self.__dict__
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class TestTransaction(unittest.TestCase):
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doRecursion = False
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def test01(self):
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"simple rollback"
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a = TestClass()
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a.test = "correct"
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a.commit()
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a.test = "roll me back"
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a.rollback()
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self.assertEqual(a.test, "correct")
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def test02(self):
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"""double rollback
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demonstrates how you can commit / rollback several times
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"""
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a = TestClass()
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a.test = "correct"
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a.commit()
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a.test = "roll me back second"
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a.commit()
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a.test = "roll me back first"
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a.rollback()
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a.rollback()
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self.assertEqual(a.test, "correct")
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def test03(self):
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"""\
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test list rollback
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showing the side effects of a non deep rollback
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"""
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a = TestClass()
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a.ls = [0, 1, 2]
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a.commit(deep=False)
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a.ls.append(3)
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a.rollback(deep=False)
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self.assertEqual(a.ls, [0, 1, 2])
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def test031(self):
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"""\
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non deep rollback
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showing the side effects of a non deep rollback
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"""
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a = TestClass()
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a.ckls = TestClass()
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b = a.ckls
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a.ckls.newvar = "correct"
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a.commit(deep=False)
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a.ckls.newvar = "roll me back"
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a.rollback(deep=False)
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self.assertEqual(b.newvar, "roll me back")
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self.assertEqual(a.ckls.newvar, "roll me back")
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def test04(self):
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"""commit not deep, rollback deep
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showing the side effects of a non deep commit
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"""
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a = TestClass()
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a.ckls = TestClass()
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a.ckls.newvar = TestClass()
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a.ckls.newvar.text = "correct"
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b = a.ckls
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a.commit(deep=False)
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a.ckls.newvar.text = "roll me back"
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a.rollback(deep=True)
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self.assertEqual(b.newvar.text, "roll me back")
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self.assertEqual(a.ckls.newvar.text, "roll me back")
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def test041(self):
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"""check for leftover attributes"""
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a = TestClass()
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a.newvar = "correct"
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a.commit()
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a.shouldnotbethere = True
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a.rollback()
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self.failIf(hasattr(a, "shouldnotbethere"), a)
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def test05(self):
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"""commit and rollback deep
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no more side effects
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"""
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a = TestClass()
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a.ckls = TestClass()
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a.ckls.newvar = "correct"
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b = a.ckls
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a.commit()
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a.ckls.newvar = "roll me back"
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a.rollback(deep=True)
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self.assertEqual(a.ckls.newvar, "correct")
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self.assertEqual(b.newvar, "correct")
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self.assertEqual(id(a.ckls), id(b))
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def test06(self):
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"""commit only a sub object
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though we committed only an attribute, the deep rollback
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will roll it back.
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"""
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a = TestClass()
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a.ckls = TestClass()
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a.newvar = "correct"
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a.ckls.newvar = "correct"
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a.ckls.commit()
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a.newvar = "will not be rolled back"
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a.ckls.newvar = "roll me back"
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a.rollback()
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self.assertEqual(a.newvar, "will not be rolled back")
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self.assertEqual(a.ckls.newvar, "correct")
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def test07(self):
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"""commit only a sub object, rollback with deep=false
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we committed only an attribute and the non deep rollback
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will not roll it back.
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"""
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a = TestClass()
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a.ckls = TestClass()
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a.newvar = "correct"
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a.ckls.newvar = "correct"
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a.ckls.commit()
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a.newvar = "will not be rolled back"
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a.ckls.newvar = "will not be rolled back"
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a.rollback(deep=False)
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self.assertEqual(a.newvar, "will not be rolled back")
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self.assertEqual(a.ckls.newvar, "will not be rolled back")
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def test10(self):
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"""check for the commit/rollback recursion"""
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if not TestTransaction.doRecursion:
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sys.stderr.write("skipped .. ")
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return
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a = TestClass()
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b = a
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for i in xrange(10):
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b.newvar = TestClass()
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b.test = "test" + str(i)
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b = b.newvar
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b.newvar = a
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# would raise a recursion maximum exception
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a.commit(deep=True)
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def test11(self):
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"""check for swapping Transaction objects"""
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a = TestClass()
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a.t1 = TestClass()
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a.t2 = TestClass()
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a.t1.text = "test1"
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a.t2.text = "test2"
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a.commit()
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b = a.t1
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a.t1 = a.t2
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a.t2 = b
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a.rollback()
|
||||
self.assertEqual(a.t1.text, "test1")
|
||||
self.assertEqual(a.t2.text, "test2")
|
||||
|
||||
def count_dict(self, seen, what):
|
||||
if id(what) in seen:
|
||||
return 1
|
||||
seen.add(id(what))
|
||||
if not hasattr(what, "__dict__"):
|
||||
return 1
|
||||
i = 1
|
||||
for val in what.__dict__.values():
|
||||
# print "Counting ", id(val), val
|
||||
i = i + self.count_dict(seen, val)
|
||||
return i
|
||||
|
||||
def test91(self):
|
||||
"""check for the stack length (deep=False)"""
|
||||
a = TestClass()
|
||||
b = a
|
||||
for i in xrange(10):
|
||||
b.newvar = TestClass()
|
||||
b.test = "test" + str(i)
|
||||
b = b.newvar
|
||||
a.commit(deep=False)
|
||||
a.commit(deep=False)
|
||||
a.commit(deep=False)
|
||||
|
||||
seen = set()
|
||||
count = self.count_dict(seen, a)
|
||||
sys.stderr.write("%d objects in %d places .. " % (len(seen), count))
|
||||
|
||||
def test92(self):
|
||||
"""check for the stack length (deep=True)"""
|
||||
a = TestClass()
|
||||
b = a
|
||||
for i in xrange(10):
|
||||
b.newvar = TestClass()
|
||||
b.test = "test" + str(i)
|
||||
b.test2 = "test2" + str(i)
|
||||
b = b.newvar
|
||||
a.commit(deep=True)
|
||||
|
||||
a.commit()
|
||||
a.commit()
|
||||
a.commit()
|
||||
|
||||
seen = set()
|
||||
count = self.count_dict(seen, a)
|
||||
sys.stderr.write("%d objects in %d places .. " % (len(seen), count))
|
||||
|
||||
|
||||
def suite():
|
||||
_suite = unittest.TestSuite()
|
||||
_suite = unittest.makeSuite(TestTransaction, "test")
|
||||
return _suite
|
||||
|
||||
|
||||
if __name__ == "__main__":
|
||||
global TestClass
|
||||
# print >> sys.stderr, """\
|
||||
# **********************************************************************
|
||||
# Old Transaction Class (original)
|
||||
# **********************************************************************
|
||||
# """
|
||||
# TestClass = TransactionOld1
|
||||
# testrunner = unittest.TextTestRunner(verbosity=2)
|
||||
# result = testrunner.run(suite())
|
||||
|
||||
# print >> sys.stderr, """\
|
||||
# **********************************************************************
|
||||
# Old Transaction Class (copy.deepcopy)
|
||||
# **********************************************************************
|
||||
# """
|
||||
# TestClass = TransactionOld2
|
||||
# testrunner = unittest.TextTestRunner(verbosity=2)
|
||||
# result = testrunner.run(suite())
|
||||
#
|
||||
|
||||
# print >> sys.stderr, """\
|
||||
# **********************************************************************
|
||||
# Old Transaction Class (copy.deepcopy + __dict__.clear)
|
||||
# **********************************************************************
|
||||
# """
|
||||
# TestClass = TransactionOld3
|
||||
# testrunner = unittest.TextTestRunner(verbosity=2)
|
||||
# result = testrunner.run(suite())
|
||||
#
|
||||
|
||||
# print >> sys.stderr, """\
|
||||
# **********************************************************************
|
||||
# New Transaction Class (deep commit)
|
||||
# **********************************************************************
|
||||
# """
|
||||
# TestClass = TransactionNew1
|
||||
# testrunner = unittest.TextTestRunner(verbosity=2)
|
||||
# result = testrunner.run(suite())
|
||||
#
|
||||
|
||||
# print >> sys.stderr, """\
|
||||
# **********************************************************************
|
||||
# New Transaction Class (deep commit + stack improvement)
|
||||
# **********************************************************************
|
||||
# """
|
||||
# TestClass = TransactionNew2
|
||||
# testrunner = unittest.TextTestRunner(verbosity=2)
|
||||
# result = testrunner.run(suite())
|
||||
#
|
||||
|
||||
# print >> sys.stderr, """\
|
||||
# **********************************************************************
|
||||
# New Transaction Class (deep commit + stack improvement + recursion check)
|
||||
# **********************************************************************
|
||||
# """
|
||||
# TestClass = TransactionNew3
|
||||
# TestTransaction.doRecursion = True
|
||||
# testrunner = unittest.TextTestRunner(verbosity=2)
|
||||
# result = testrunner.run(suite())
|
||||
|
||||
print >> sys.stderr, """\
|
||||
**********************************************************************
|
||||
New Transaction Class (final)
|
||||
**********************************************************************
|
||||
"""
|
||||
TestClass = TransactionImproved
|
||||
TestTransaction.doRecursion = True
|
||||
testrunner = unittest.TextTestRunner(verbosity=2)
|
||||
result = testrunner.run(suite())
|
||||
|
||||
sys.exit(not result.wasSuccessful())
|
||||
Loading…
Reference in a new issue