Now transactional to some extent.

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@12648 20353a03-c40f-0410-a6d1-a30d3c3de9de

product/ERP5Type/TM.py

+##############################################################################
+#
+# Copyright (c) 2001 Zope Corporation and Contributors. All Rights Reserved.
+#
+# This software is subject to the provisions of the Zope Public License,
+# Version 2.0 (ZPL).  A copy of the ZPL should accompany this distribution.
+# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
+# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
+# FOR A PARTICULAR PURPOSE
+#
+##############################################################################
+"""Provide support for linking an external transaction manager with Zope's
+"""
+
+
+class VTM:
+    """Mix-in class that provides transaction management support
+
+    A sub class should call self._register() whenever it performs any
+    transaction-dependent operations (e.g. sql statements).
+
+    The sub class will need to override _finish, to finalize work,
+    _abort, to roll-back work, and perhaps _begin, if any work is
+    needed at the start of a transaction.
+
+    A subclass that uses locking during transaction commit must
+    defined a sortKey() method.
+
+    The VTM variety can be mixed-in with persistent classes.
+    """
+
+    _v_registered=0
+    _v_finalize=0
+
+    def _begin(self): pass
+
+    def _register(self):
+        if not self._v_registered:
+            try:
+                get_transaction().register(Surrogate(self))
+                self._begin()
+                self._v_registered = 1
+                self._v_finalize = 0
+            except: 
+                pass
+
+    def tpc_begin(self, *ignored): pass
+    commit=tpc_begin
+
+    def _finish(self):
+        raise NotImplementedError
+
+    def _abort(self):
+        raise NotImplementedError
+
+    def tpc_vote(self, *ignored):
+        self._v_finalize = 1
+
+    def tpc_finish(self, *ignored):
+        if self._v_finalize:
+            try: 
+                self._finish()
+            finally: 
+                self._v_registered=0
+                self._v_finalize=0
+
+    def abort(self, *ignored):
+        try: 
+            self._abort()
+        finally: 
+            self._v_registered=0
+            self._v_finalize=0
+
+    tpc_abort = abort
+
+    def sortKey(self, *ignored):
+        """ The sortKey method is used for recent ZODB compatibility which
+            needs to have a known commit order for lock acquisition.  Most
+            DA's talking to RDBMS systems do not care about commit order, so
+            return the constant 1
+        """
+        return 1
+
+class Surrogate:
+
+    def __init__(self, db):
+        self._p_jar=db
+        self.__inform_commit__=db.tpc_finish
+        self.__inform_abort__=db.tpc_abort