File: SingleThreadedTransaction.py

package info (click to toggle)
python-bobopos 2.1-3
  • links: PTS
  • area: main
  • in suites: potato
  • size: 236 kB
  • ctags: 220
  • sloc: python: 1,774; makefile: 38; sh: 24
file content (161 lines) | stat: -rw-r--r-- 5,358 bytes parent folder | download | duplicates (3)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
##############################################################################
#
# 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()