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##############################################################################
#
# Copyright (c) 1996-1998, Digital Creations, Fredericksburg, VA, USA.
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
#
# o Redistributions of source code must retain the above copyright
# notice, this list of conditions, and the disclaimer that follows.
#
# o Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions, and the following disclaimer in
# the documentation and/or other materials provided with the
# distribution.
#
# o Neither the name of Digital Creations nor the names of its
# contributors may be used to endorse or promote products derived
# from this software without specific prior written permission.
#
#
# THIS SOFTWARE IS PROVIDED BY DIGITAL CREATIONS AND CONTRIBUTORS *AS IS*
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
# TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
# PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL DIGITAL
# CREATIONS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
# OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
# TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
# USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
# DAMAGE.
#
#
# If you have questions regarding this software, contact:
#
# Digital Creations, L.C.
# 910 Princess Ann Street
# Fredericksburge, Virginia 22401
#
# info@digicool.com
#
# (540) 371-6909
#
##############################################################################
__doc__='''A very simple HTTP transaction manager.
This module provides a very simple transaction manager for
HTTP requests in a single-threaded application environment.
(Future versions of this module may support multiple transactions.)
This module treats each HTTP request as a transaction.
To use, import the module and then call the 'install' function.
This will install the function 'get_transaction'. This function will
be used by transactional objects to get the current transaction.
$Id: SingleThreadedTransaction.py,v 1.14 1998/10/23 21:43:38 jim Exp $'''
__version__='$Revision: 1.14 $'[11:-2]
# Install myself before anything else happens:
def get_transaction(): return theTransaction
import __main__
__main__.__builtins__.get_transaction=get_transaction
import time, sys
# The following are for backward compatibility:
from PickleDictionary import PickleDictionary
from Persistence import Persistent
class Transactional:
'''Base class for all transactional objects
Transactional objects, like persistent objects track
changes in state. Unlike persistent objects, transactional
objects work in conjunction with a transaction manager to manage
saving state and recovering from errors.
'''
def __changed__(self,v=None):
if v and not self._p_changed:
try: get_transaction().register(self)
except: pass
return Persistence.Persistent.__changed__(self,v)
def __inform_commit__(self,transaction,start_time):
self.__save__()
def __inform_abort__(self,transaction,start_time):
try: self._p_jar.abort(self,start_time)
except: pass
class Transaction:
'Simple transaction objects for single-threaded applications.'
Aborted='TransactionAborted'
now=time.time()
_note=''
def _clear(self):
self._objects=[]
self._append=self._objects.append
self.now=time.time()
__init__=_clear
def abort(self):
'''Abort the transaction.
All objects participating in the current transaction will be
informed of the abort so that they can roll back changes or
forget pending changes.
'''
if self._objects:
for o in tuple(self._objects):
try:
o.__inform_abort__(self,self.now)
except: pass
self._clear()
_abort=abort
def begin(self,note=''):
'''Begin a new transaction.
This aborts any transaction in progres.
'''
if self._objects: self._abort()
else: self._clear()
self._note=note
def note(self,note): self._note=note
def info(self): return "%.3f\t%s" % (self.now,self._note)
def commit(self):
'Finalize the transaction'
try:
for o in tuple(self._objects):
o.__inform_commit__(self,self.now)
except:
t,v,tb=sys.exc_type, sys.exc_value, sys.exc_traceback
try:
self.abort()
sys.exc_type, sys.exc_value, sys.exc_traceback=t,v,tb
except: pass
tb=None
raise sys.exc_type, sys.exc_value, sys.exc_traceback
self._clear()
def register(self,object):
'Register the given object for transaction control.'
self._append(object)
theTransaction=Transaction()
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