Merge the jeremy-txn-branch to the head.

This branch introduces a new transaction API.  The key features are:
  - top-level functions in transaction -- get(), commit(), abort()
  - explicit transaction manager objects
  - Transaction objects are used for exactly one transaction
  - support for transaction synchronizers

The changes here are still provisional, but we want to get them off an
obscure branch and onto the head for further development.

src/ZEO/StorageServer.py

@@ -27,6 +27,8 @@ import sys
 import threading
 import time
 
+import transaction
+
 from ZEO import ClientStub
 from ZEO.CommitLog import CommitLog
 from ZEO.monitor import StorageStats, StatsServer
@@ -40,7 +42,6 @@ from ZODB.ConflictResolution import ResolvedSerial
 from ZODB.POSException import StorageError, StorageTransactionError
 from ZODB.POSException import TransactionError, ReadOnlyError, ConflictError
 from ZODB.serialize import referencesf
-from ZODB.Transaction import Transaction
 from ZODB.utils import u64, oid_repr
 
 _label = "ZSS" # Default label used for logging.
@@ -365,7 +366,7 @@ class ZEOStorage:
                 raise StorageTransactionError("Multiple simultaneous tpc_begin"
                                               " requests from one client.")
 
-        self.transaction = t = Transaction()
+        self.transaction = t = transaction.Transaction()
         t.id = id
         t.user = user
         t.description = description

src/ZEO/tests/Cache.py

@@ -13,10 +13,11 @@
 ##############################################################################
 """Tests of the ZEO cache"""
 
-from ZODB.Transaction import Transaction
 from ZODB.tests.MinPO import MinPO
 from ZODB.tests.StorageTestBase import zodb_unpickle
 
+from transaction import Transaction
+
 class TransUndoStorageWithCache:
 
     def checkUndoInvalidation(self):

src/ZEO/tests/CommitLockTests.py

@@ -16,8 +16,8 @@
 import threading
 import time
 
-from ZODB.Transaction import Transaction
 from persistent.TimeStamp import TimeStamp
+import transaction
 from ZODB.tests.StorageTestBase import zodb_pickle, MinPO
 
 import ZEO.ClientStorage
@@ -97,7 +97,7 @@ class CommitLockTests:
         self._storages = []
 
     def _start_txn(self):
-        txn = Transaction()
+        txn = transaction.Transaction()
         self._storage.tpc_begin(txn)
         oid = self._storage.new_oid()
         self._storage.store(oid, ZERO, zodb_pickle(MinPO(1)), '', txn)
@@ -112,7 +112,7 @@ class CommitLockTests:
 
         for i in range(self.NUM_CLIENTS):
             storage = self._duplicate_client()
-            txn = Transaction()
+            txn = transaction.Transaction()
             tid = self._get_timestamp()
 
             t = WorkerThread(self, storage, txn)

src/ZEO/tests/ConnectionTests.py

@@ -29,13 +29,15 @@ from ZEO.zrpc.marshal import Marshaller
 from ZEO.tests import forker
 
 from ZODB.DB import DB
-from ZODB.Transaction import get_transaction, Transaction
 from ZODB.POSException import ReadOnlyError, ConflictError
 from ZODB.tests.StorageTestBase import StorageTestBase
 from ZODB.tests.MinPO import MinPO
 from ZODB.tests.StorageTestBase \
      import zodb_pickle, zodb_unpickle, handle_all_serials, handle_serials
 
+import transaction
+from transaction import Transaction
+
 ZERO = '\0'*8
 
 class TestServerStub(ZEO.ServerStub.StorageServer):
@@ -465,7 +467,7 @@ class ConnectionTests(CommonSetupTearDown):
                 zLOG.LOG("checkReconnection", zLOG.INFO,
                          "Error after server restart; retrying.",
                          error=sys.exc_info())
-                get_transaction().abort()
+                transaction.abort()
             # Give the other thread a chance to run.
             time.sleep(0.1)
         zLOG.LOG("checkReconnection", zLOG.INFO, "finished")
@@ -552,7 +554,7 @@ class ConnectionTests(CommonSetupTearDown):
         r1 = c1.root()
 
         r1["a"] = MinPO("a")
-        get_transaction().commit()
+        transaction.commit()
 
         db2 = DB(self.openClientStorage())
         r2 = db2.open().root()
@@ -560,7 +562,7 @@ class ConnectionTests(CommonSetupTearDown):
         self.assertEqual(r2["a"].value, "a")
 
         r2["b"] = MinPO("b")
-        get_transaction().commit()
+        transaction.commit()
 
         # make sure the invalidation is received in the other client
         for i in range(10):

src/ZEO/tests/InvalidationTests.py

@@ -16,6 +16,8 @@ import threading
 import time
 from random import Random
 
+import transaction
+
 from BTrees.check import check, display
 from BTrees.OOBTree import OOBTree
 
@@ -70,8 +72,7 @@ class StressTask:
         self.step = step
         self.sleep = sleep
         self.added_keys = []
-        self.cn = self.db.open()
-        self.cn.setLocalTransaction()
+        self.cn = self.db.open(txn_mgr=transaction.TransactionManager())
         self.cn.sync()
 
     def doStep(self):

src/ZEO/tests/ThreadTests.py

@@ -15,9 +15,8 @@
 
 import threading
 
-from ZODB.Transaction import Transaction
+import transaction
 from ZODB.tests.StorageTestBase import zodb_pickle, MinPO
-
 import ZEO.ClientStorage
 
 ZERO = '\0'*8
@@ -25,7 +24,7 @@ ZERO = '\0'*8
 class BasicThread(threading.Thread):
     def __init__(self, storage, doNextEvent, threadStartedEvent):
         self.storage = storage
-        self.trans = Transaction()
+        self.trans = transaction.Transaction()
         self.doNextEvent = doNextEvent
         self.threadStartedEvent = threadStartedEvent
         self.gotValueError = 0

src/ZODB/DB.py

@@ -13,7 +13,7 @@
 ##############################################################################
 """Database objects
 
-$Id: DB.py,v 1.71 2004/03/16 16:28:19 jeremy Exp $"""
+$Id: DB.py,v 1.72 2004/04/01 03:56:58 jeremy Exp $"""
 
 import cPickle, cStringIO, sys
 from thread import allocate_lock
@@ -23,9 +23,10 @@ import warnings
 from ZODB.broken import find_global
 from ZODB.Connection import Connection
 from ZODB.serialize import referencesf
-from ZODB.Transaction import Transaction, get_transaction
 from zLOG import LOG, ERROR
 
+import transaction
+
 class DB(object):
     """The Object Database
     -------------------
@@ -132,7 +133,7 @@ class DB(object):
             p = cPickle.Pickler(file, 1)
             p.dump((root.__class__, None))
             p.dump(root.__getstate__())
-            t = Transaction()
+            t = transaction.Transaction()
             t.description = 'initial database creation'
             storage.tpc_begin(t)
             storage.store('\0\0\0\0\0\0\0\0', None, file.getvalue(), '', t)
@@ -140,13 +141,12 @@ class DB(object):
             storage.tpc_finish(t)
 
         # Pass through methods:
-        for m in ('history',
-                  'supportsUndo', 'supportsVersions', 'undoLog',
-                  'versionEmpty', 'versions'):
+        for m in ['history', 'supportsUndo', 'supportsVersions', 'undoLog',
+                  'versionEmpty', 'versions']:
             setattr(self, m, getattr(storage, m))
 
         if hasattr(storage, 'undoInfo'):
-            self.undoInfo=storage.undoInfo
+            self.undoInfo = storage.undoInfo
 
 
     def _cacheMean(self, attr):
@@ -206,10 +206,10 @@ class DB(object):
                 self._temps=t
         finally: self._r()
 
-    def abortVersion(self, version, transaction=None):
-        if transaction is None:
-            transaction = get_transaction()
-        transaction.register(AbortVersion(self, version))
+    def abortVersion(self, version, txn=None):
+        if txn is None:
+            txn = transaction.get()
+        txn.register(AbortVersion(self, version))
 
     def cacheDetail(self):
         """Return information on objects in the various caches
@@ -316,10 +316,10 @@ class DB(object):
         """
         self._storage.close()
 
-    def commitVersion(self, source, destination='', transaction=None):
-        if transaction is None:
-            transaction = get_transaction()
-        transaction.register(CommitVersion(self, source, destination))
+    def commitVersion(self, source, destination='', txn=None):
+        if txn is None:
+            txn = transaction.get()
+        txn.register(CommitVersion(self, source, destination))
 
     def getCacheSize(self):
         return self._cache_size
@@ -391,7 +391,7 @@ class DB(object):
         return len(self._storage)
 
     def open(self, version='', transaction=None, temporary=0, force=None,
-             waitflag=1, mvcc=True):
+             waitflag=1, mvcc=True, txn_mgr=None):
         """Return a database Connection for use by application code.
 
         The optional version argument can be used to specify that a
@@ -424,7 +424,7 @@ class DB(object):
                 # a one-use connection.
                 c = self.klass(version=version,
                                cache_size=self._version_cache_size,
-                               mvcc=mvcc)
+                               mvcc=mvcc, txn_mgr=txn_mgr)
                 c._setDB(self)
                 self._temps.append(c)
                 if transaction is not None:
@@ -474,13 +474,13 @@ class DB(object):
                     if self._version_pool_size > len(allocated) or force:
                         c = self.klass(version=version,
                                        cache_size=self._version_cache_size,
-                                       mvcc=mvcc)
+                                       mvcc=mvcc, txn_mgr=txn_mgr)
                         allocated.append(c)
                         pool.append(c)
                 elif self._pool_size > len(allocated) or force:
                     c = self.klass(version=version,
                                    cache_size=self._cache_size,
-                                   mvcc=mvcc)
+                                   mvcc=mvcc, txn_mgr=txn_mgr)
                     allocated.append(c)
                     pool.append(c)
 
@@ -611,7 +611,7 @@ class DB(object):
 
     def cacheStatistics(self): return () # :(
 
-    def undo(self, id, transaction=None):
+    def undo(self, id, txn=None):
         """Undo a transaction identified by id.
 
         A transaction can be undone if all of the objects involved in
@@ -625,12 +625,12 @@ class DB(object):
 
         :Parameters:
           - `id`: a storage-specific transaction identifier
-          - `transaction`: transaction context to use for undo().
+          - `txn`: transaction context to use for undo().
             By default, uses the current transaction.
         """
-        if transaction is None:
-            transaction = get_transaction()
-        transaction.register(TransactionalUndo(self, id))
+        if txn is None:
+            txn = transaction.get()
+        txn.register(TransactionalUndo(self, id))
 
     def versionEmpty(self, version):
         return self._storage.versionEmpty(version)
@@ -663,7 +663,6 @@ class ResourceManager(object):
     def __init__(self, db):
         self._db = db
         # Delegate the actual 2PC methods to the storage
-        self.tpc_begin = self._db._storage.tpc_begin
         self.tpc_vote = self._db._storage.tpc_vote
         self.tpc_finish = self._db._storage.tpc_finish
         self.tpc_abort = self._db._storage.tpc_abort
@@ -671,13 +670,19 @@ class ResourceManager(object):
     def sortKey(self):
         return "%s:%s" % (self._db._storage.sortKey(), id(self))
 
+    def tpc_begin(self, txn, sub=False):
+        # XXX we should never be called with sub=True.
+        if sub:
+            raise ValueError, "doesn't supoprt sub-transactions"
+        self._db._storage.tpc_begin(txn)
+
     # The object registers itself with the txn manager, so the ob
     # argument to the methods below is self.
 
-    def abort(self, ob, t):
+    def abort(self, obj, txn):
         pass
 
-    def commit(self, ob, t):
+    def commit(self, obj, txn):
         pass
 
 class CommitVersion(ResourceManager):

src/ZODB/MappingStorage.py

@@ -21,7 +21,7 @@ It is meant to illustrate the simplest possible storage.
 The Mapping storage uses a single data structure to map object ids to data.
 """
 
-__version__='$Revision: 1.12 $'[11:-2]
+__version__='$Revision: 1.13 $'[11:-2]
 
 from ZODB import utils
 from ZODB import BaseStorage
@@ -68,6 +68,16 @@ class MappingStorage(BaseStorage.BaseStorage):
         finally:
             self._lock_release()
 
+    def getTid(self, oid):
+        self._lock_acquire()
+        try:
+            # The tid is the first 8 bytes of the buffer.
+            s = self._index[oid]
+            return s[:8]
+        finally:
+            self._lock_release()
+        
+
     def store(self, oid, serial, data, version, transaction):
         if transaction is not self._transaction:
             raise POSException.StorageTransactionError(self, transaction)

src/ZODB/TmpStore.py

@@ -22,8 +22,9 @@ class TmpStore:
 
     _bver = ''
 
-    def __init__(self, base_version):
+    def __init__(self, base_version, storage):
         self._transaction = None
+        self._storage = storage
         if base_version:
             self._bver = base_version
         self._file = tempfile.TemporaryFile()
@@ -34,14 +35,13 @@ class TmpStore:
         self._index = {}
         # _tindex: map oid to pos for new updates
         self._tindex = {}
-        self._db = None
         self._creating = []
 
     def close(self):
         self._file.close()
 
     def getName(self):
-        return self._db.getName()
+        return self._storage.getName()
 
     def getSize(self):
         return self._pos
@@ -66,14 +66,13 @@ class TmpStore:
     def modifiedInVersion(self, oid):
         if self._index.has_key(oid):
             return self._bver
-        return self._db._storage.modifiedInVersion(oid)
+        return self._storage.modifiedInVersion(oid)
 
     def new_oid(self):
-        return self._db._storage.new_oid()
+        return self._storage.new_oid()
 
     def registerDB(self, db, limit):
-        self._db = db
-        self._storage = db._storage
+        pass
 
     def store(self, oid, serial, data, version, transaction):
         if transaction is not self._transaction:

src/ZODB/Transaction.py

@@ -13,7 +13,7 @@
 ##############################################################################
 """Transaction management
 
-$Id: Transaction.py,v 1.58 2004/02/27 00:31:53 faassen Exp $
+$Id: Transaction.py,v 1.59 2004/04/01 03:56:58 jeremy Exp $
 """
 import sys
 from thread import get_ident as _get_ident
@@ -64,6 +64,7 @@ class Transaction:
         self._id=id
         self._objects=[]
         self._append=self._objects.append
+        raise RuntimeError
 
     def _init(self):
         self._objects=[]
@@ -532,25 +533,27 @@ class DataManagerAdapter(object):
 ############################################################################
 # install get_transaction:
 
-# Map thread ident to its Transaction instance.
-_tid2tran = {}
-
-# Get Transaction associated with current thread; if none, create a
-# new Transaction and return it.
-def get_transaction():
-    tid = _get_ident()
-    result = _tid2tran.get(tid)
-    if result is None:
-        _tid2tran[tid] = result = Transaction(tid)
-    return result
-
-# Forget whatever Transaction (if any) is associated with current thread.
-def free_transaction():
-    tid = _get_ident()
-    try:
-        del _tid2tran[tid]
-    except KeyError:
-        pass
+### Map thread ident to its Transaction instance.
+##_tid2tran = {}
+
+### Get Transaction associated with current thread; if none, create a
+### new Transaction and return it.
+##def get_transaction():
+##    tid = _get_ident()
+##    result = _tid2tran.get(tid)
+##    if result is None:
+##        _tid2tran[tid] = result = Transaction(tid)
+##    return result
+
+### Forget whatever Transaction (if any) is associated with current thread.
+##def free_transaction():
+##    tid = _get_ident()
+##    try:
+##        del _tid2tran[tid]
+##    except KeyError:
+##        pass
+
+from transaction import get as get_transaction
 
 import __builtin__
 __builtin__.get_transaction = get_transaction

src/ZODB/tests/BasicStorage.py

@@ -19,20 +19,20 @@ http://www.zope.org/Documentation/Developer/Models/ZODB/ZODB_Architecture_Storag
 All storages should be able to pass these tests.
 """
 
-from ZODB.Transaction import Transaction
 from ZODB import POSException
-
 from ZODB.tests.MinPO import MinPO
 from ZODB.tests.StorageTestBase \
      import zodb_unpickle, zodb_pickle, handle_serials
 
+import transaction
+
 ZERO = '\0'*8
 
 
 
 class BasicStorage:
     def checkBasics(self):
-        t = Transaction()
+        t = transaction.Transaction()
         self._storage.tpc_begin(t)
         # This should simply return
         self._storage.tpc_begin(t)
@@ -44,10 +44,10 @@ class BasicStorage:
         self.assertRaises(
             POSException.StorageTransactionError,
             self._storage.store,
-            0, 0, 0, 0, Transaction())
+            0, 0, 0, 0, transaction.Transaction())
 
         try:
-            self._storage.abortVersion('dummy', Transaction())
+            self._storage.abortVersion('dummy', transaction.Transaction())
         except (POSException.StorageTransactionError,
                 POSException.VersionCommitError):
             pass # test passed ;)
@@ -55,7 +55,7 @@ class BasicStorage:
             assert 0, "Should have failed, invalid transaction."
 
         try:
-            self._storage.commitVersion('dummy', 'dummer', Transaction())
+            self._storage.commitVersion('dummy', 'dummer', transaction.Transaction())
         except (POSException.StorageTransactionError,
                 POSException.VersionCommitError):
             pass # test passed ;)
@@ -65,13 +65,13 @@ class BasicStorage:
         self.assertRaises(
             POSException.StorageTransactionError,
             self._storage.store,
-            0, 1, 2, 3, Transaction())
+            0, 1, 2, 3, transaction.Transaction())
         self._storage.tpc_abort(t)
 
     def checkSerialIsNoneForInitialRevision(self):
         eq = self.assertEqual
         oid = self._storage.new_oid()
-        txn = Transaction()
+        txn = transaction.Transaction()
         self._storage.tpc_begin(txn)
         # Use None for serial.  Don't use _dostore() here because that coerces
         # serial=None to serial=ZERO.
@@ -120,7 +120,7 @@ class BasicStorage:
 
     def checkWriteAfterAbort(self):
         oid = self._storage.new_oid()
-        t = Transaction()
+        t = transaction.Transaction()
         self._storage.tpc_begin(t)
         self._storage.store(oid, ZERO, zodb_pickle(MinPO(5)), '', t)
         # Now abort this transaction
@@ -133,7 +133,7 @@ class BasicStorage:
         oid1 = self._storage.new_oid()
         revid1 = self._dostore(oid=oid1, data=MinPO(-2))
         oid = self._storage.new_oid()
-        t = Transaction()
+        t = transaction.Transaction()
         self._storage.tpc_begin(t)
         self._storage.store(oid, ZERO, zodb_pickle(MinPO(5)), '', t)
         # Now abort this transaction
@@ -176,7 +176,7 @@ class BasicStorage:
 
     def checkTwoArgBegin(self):
         # XXX how standard is three-argument tpc_begin()?
-        t = Transaction()
+        t = transaction.Transaction()
         tid = '\0\0\0\0\0psu'
         self._storage.tpc_begin(t, tid)
         oid = self._storage.new_oid()
@@ -205,7 +205,7 @@ class BasicStorage:
 
     def checkNote(self):
         oid = self._storage.new_oid()
-        t = Transaction()
+        t = transaction.Transaction()
         self._storage.tpc_begin(t)
         t.note('this is a test')
         self._storage.store(oid, ZERO, zodb_pickle(MinPO(5)), '', t)

src/ZODB/tests/ConflictResolution.py

@@ -13,9 +13,9 @@
 ##############################################################################
 """Tests for application-level conflict resolution."""
 
-from ZODB.Transaction import Transaction
 from ZODB.POSException import ConflictError, UndoError
 from persistent import Persistent
+from transaction import Transaction
 
 from ZODB.tests.StorageTestBase import zodb_unpickle, zodb_pickle
 

src/ZODB/tests/HistoryStorage.py

@@ -17,8 +17,8 @@ Any storage that supports the history() method should be able to pass
 all these tests.
 """
 
-from ZODB.Transaction import Transaction
 from ZODB.tests.MinPO import MinPO
+from transaction import Transaction
 
 class HistoryStorage:
     def checkSimpleHistory(self):

src/ZODB/tests/IteratorStorage.py

@@ -20,8 +20,8 @@ all these tests.
 from ZODB.tests.MinPO import MinPO
 from ZODB.tests.StorageTestBase import zodb_pickle, zodb_unpickle
 from ZODB.utils import U64, p64
-from ZODB.Transaction import Transaction
 
+from transaction import Transaction
 
 class IteratorCompare:
 

src/ZODB/tests/MTStorage.py

@@ -3,13 +3,13 @@ import sys
 import threading
 import time
 
-import ZODB
 from persistent.mapping import PersistentMapping
+import transaction
 
+import ZODB
 from ZODB.tests.StorageTestBase \
      import zodb_pickle, zodb_unpickle, handle_serials
 from ZODB.tests.MinPO import MinPO
-from ZODB.Transaction import Transaction
 from ZODB.POSException import ConflictError
 
 SHORT_DELAY = 0.01
@@ -59,6 +59,7 @@ class ZODBClientThread(TestThread):
 
     def runtest(self):
         conn = self.db.open()
+        conn.sync()
         root = conn.root()
         d = self.get_thread_dict(root)
         if d is None:
@@ -126,7 +127,7 @@ class StorageClientThread(TestThread):
 
     def dostore(self, i):
         data = zodb_pickle(MinPO((self.getName(), i)))
-        t = Transaction()
+        t = transaction.Transaction()
         oid = self.oid()
         self.pause()
 

src/ZODB/tests/PackableStorage.py

@@ -127,7 +127,7 @@ class PackableStorageBase:
         try:
             self._storage.load(ZERO, '')
         except KeyError:
-            from ZODB.Transaction import Transaction
+            from transaction import Transaction
             file = StringIO()
             p = cPickle.Pickler(file, 1)
             p.dump((PersistentMapping, None))

src/ZODB/tests/ReadOnlyStorage.py

@@ -12,7 +12,7 @@
 #
 ##############################################################################
 from ZODB.POSException import ReadOnlyError, Unsupported
-from ZODB.Transaction import Transaction
+import transaction
 
 class ReadOnlyStorage:
 
@@ -47,7 +47,7 @@ class ReadOnlyStorage:
     def checkWriteMethods(self):
         self._make_readonly()
         self.assertRaises(ReadOnlyError, self._storage.new_oid)
-        t = Transaction()
+        t = transaction.Transaction()
         self.assertRaises(ReadOnlyError, self._storage.tpc_begin, t)
 
         if self._storage.supportsVersions():

src/ZODB/tests/RecoveryStorage.py

@@ -13,7 +13,7 @@
 ##############################################################################
 """More recovery and iterator tests."""
 
-from ZODB.Transaction import Transaction
+from transaction import Transaction
 from ZODB.tests.IteratorStorage import IteratorDeepCompare
 from ZODB.tests.StorageTestBase import MinPO, zodb_unpickle, snooze
 from ZODB import DB

src/ZODB/tests/RevisionStorage.py

@@ -16,9 +16,10 @@
 from ZODB.tests.MinPO import MinPO
 from ZODB.tests.StorageTestBase import \
      zodb_unpickle, zodb_pickle, snooze, handle_serials
-from ZODB.Transaction import Transaction
 from ZODB.utils import p64, u64
 
+import transaction
+
 ZERO = '\0'*8
 
 class RevisionStorage:
@@ -142,7 +143,7 @@ class RevisionStorage:
         oid = self._storage.new_oid()
         def helper(tid, revid, x):
             data = zodb_pickle(MinPO(x))
-            t = Transaction()
+            t = transaction.Transaction()
             try:
                 self._storage.tpc_begin(t, p64(tid))
                 r1 = self._storage.store(oid, revid, data, '', t)

src/ZODB/tests/StorageTestBase.py

@@ -26,9 +26,9 @@ import unittest
 from cPickle import Pickler, Unpickler
 from cStringIO import StringIO
 
-from ZODB.Transaction import Transaction
-from ZODB.utils import u64
+import transaction
 
+from ZODB.utils import u64
 from ZODB.tests.MinPO import MinPO
 
 ZERO = '\0'*8
@@ -184,7 +184,7 @@ class StorageTestBase(unittest.TestCase):
         if version is None:
             version = ''
         # Begin the transaction
-        t = Transaction()
+        t = transaction.Transaction()
         if user is not None:
             t.user = user
         if description is not None:
@@ -211,7 +211,7 @@ class StorageTestBase(unittest.TestCase):
     def _undo(self, tid, expected_oids=None, note=None):
         # Undo a tid that affects a single object (oid).
         # XXX This is very specialized
-        t = Transaction()
+        t = transaction.Transaction()
         t.note(note or "undo")
         self._storage.tpc_begin(t)
         tid, oids = self._storage.undo(tid, t)
@@ -224,7 +224,7 @@ class StorageTestBase(unittest.TestCase):
         return self._storage.lastTransaction()
 
     def _commitVersion(self, src, dst):
-        t = Transaction()
+        t = transaction.Transaction()
         t.note("commit %r to %r" % (src, dst))
         self._storage.tpc_begin(t)
         tid, oids = self._storage.commitVersion(src, dst, t)
@@ -233,7 +233,7 @@ class StorageTestBase(unittest.TestCase):
         return oids
 
     def _abortVersion(self, ver):
-        t = Transaction()
+        t = transaction.Transaction()
         t.note("abort %r" % ver)
         self._storage.tpc_begin(t)
         tid, oids = self._storage.abortVersion(ver, t)

src/ZODB/tests/Synchronization.py

@@ -62,7 +62,7 @@ tested?  Is it a general restriction?
 
 """
 
-from ZODB.Transaction import Transaction
+from transaction import Transaction
 from ZODB.POSException import StorageTransactionError
 
 VERSION = "testversion"

src/ZODB/tests/TransactionalUndoStorage.py

@@ -18,13 +18,15 @@ Any storage that supports undo() must pass these tests.
 
 import time
 import types
+
+from persistent import Persistent
+from transaction import Transaction
+
 from ZODB import POSException
-from ZODB.Transaction import Transaction
 from ZODB.serialize import referencesf
 from ZODB.utils import p64
 from ZODB import DB
 
-from persistent import Persistent
 from ZODB.tests.MinPO import MinPO
 from ZODB.tests.StorageTestBase import zodb_pickle, zodb_unpickle
 

src/ZODB/tests/TransactionalUndoVersionStorage.py

@@ -16,8 +16,9 @@
 
 import time
 
+import transaction
+
 from ZODB.serialize import referencesf
-from ZODB.Transaction import Transaction
 from ZODB.tests.MinPO import MinPO
 from ZODB.tests.StorageTestBase import zodb_unpickle
 
@@ -114,7 +115,7 @@ class TransactionalUndoVersionStorage:
                         version=version, description='version2')
         self._x_dostore(description='create2')
 
-        t = Transaction()
+        t = transaction.Transaction()
         t.description = 'commit version'
         self._storage.tpc_begin(t)
         self._storage.commitVersion(version, '', t)

src/ZODB/tests/VersionStorage.py

@@ -18,9 +18,10 @@ Any storage that supports versions should be able to pass all these tests.
 
 import time
 
+from transaction import Transaction
+
 from ZODB import POSException
 from ZODB.serialize import referencesf
-from ZODB.Transaction import Transaction
 from ZODB.tests.MinPO import MinPO
 from ZODB.tests.StorageTestBase import zodb_unpickle, snooze
 from ZODB import DB

src/ZODB/tests/testConnection.py

@@ -483,8 +483,6 @@ class StubStorage:
     appended to self._finished.
     """
 
-    sortKey = 'StubStorage sortKey'
-
     # internal
     _oid = 1
     _transaction = None
@@ -502,6 +500,9 @@ class StubStorage:
         self._oid += 1
         return oid
 
+    def sortKey(self):
+        return 'StubStorage sortKey'
+
     def tpc_begin(self, transaction):
         if transaction is None:
             raise TypeError('transaction may not be None')

src/ZODB/tests/testFileStorage.py

@@ -11,9 +11,9 @@
 # FOR A PARTICULAR PURPOSE.
 #
 ##############################################################################
-import ZODB.FileStorage
 import os, unittest
-from ZODB.Transaction import Transaction
+import transaction
+import ZODB.FileStorage
 from ZODB import POSException
 
 from ZODB.tests import StorageTestBase, BasicStorage, \
@@ -195,7 +195,7 @@ class SlowFileStorageTest(BaseFileStorageTests):
         # every 8000 calls.  Make sure it gets minimal coverage.
         oids = [[self._storage.new_oid(), None] for i in range(100)]
         for i in range(100):
-            t = Transaction()
+            t = transaction.Transaction()
             self._storage.tpc_begin(t)
             for j in range(100):
                 o = MinPO(j)

src/ZODB/tests/testTransaction.py

@@ -11,13 +11,7 @@
 # FOR A PARTICULAR PURPOSE
 #
 ##############################################################################
-
-"""
-Revision information:
-$Id: testTransaction.py,v 1.19 2004/02/27 00:31:55 faassen Exp $
-"""
-
-"""
+"""Test tranasction behavior for variety of cases.
 
 I wrote these unittests to investigate some odd transaction
 behavior when doing unittests of integrating non sub transaction
@@ -42,26 +36,24 @@ TODO
     add in tests for objects which are modified multiple times,
     for example an object that gets modified in multiple sub txns.
 
+$Id: testTransaction.py,v 1.20 2004/04/01 03:56:57 jeremy Exp $
 """
 
-from types import TupleType
 import unittest
-
-from ZODB import Transaction
+import transaction
 
 class TransactionTests(unittest.TestCase):
 
     def setUp(self):
-
-        Transaction.hosed = 0
+        self.orig_tm = transaction.manager
+        transaction.manager = transaction.TransactionManager()
         self.sub1 = DataObject()
         self.sub2 = DataObject()
         self.sub3 = DataObject()
         self.nosub1 = DataObject(nost=1)
 
     def tearDown(self):
-
-        Transaction.free_transaction()
+        transaction.manager = self.orig_tm
 
     # basic tests with two sub trans jars
     # really we only need one, so tests for
@@ -124,18 +116,12 @@ class TransactionTests(unittest.TestCase):
         assert self.sub1._p_jar.cabort_sub == 1
 
     def testMultipleSubTransactionCommitCommit(self):
-
-        # add it
         self.sub1.modify()
-
         get_transaction().commit(1)
 
-        # add another
         self.sub2.modify()
-
         # reset a flag on the original to test it again
         self.sub1.ctpc_finish = 0
-
         get_transaction().commit(1)
 
         # this is interesting.. we go through
@@ -150,7 +136,7 @@ class TransactionTests(unittest.TestCase):
 
         get_transaction().commit()
 
-        # we did an implicit sub commit, is this impl artifiact?
+        # we did an implicit sub commit, is this impl artifact?
         assert self.sub3._p_jar.ccommit_sub == 1
         assert self.sub1._p_jar.ctpc_finish > 1
 
@@ -350,7 +336,6 @@ class TransactionTests(unittest.TestCase):
         assert self.nosub1._p_jar.ctpc_finish == 0
         assert self.nosub1._p_jar.ccommit == 1
         assert self.nosub1._p_jar.ctpc_abort == 1
-        assert Transaction.hosed == 0
 
     def testExceptionInTpcVote(self):
 
@@ -367,7 +352,6 @@ class TransactionTests(unittest.TestCase):
         assert self.nosub1._p_jar.ccommit == 1
         assert self.nosub1._p_jar.ctpc_abort == 1
         assert self.sub1._p_jar.ctpc_abort == 1
-        assert Transaction.hosed == 0
 
     def testExceptionInTpcBegin(self):
         """
@@ -406,29 +390,18 @@ class TransactionTests(unittest.TestCase):
         except TestTxnException: pass
 
         assert self.nosub1._p_jar.ctpc_abort == 1
-        assert Transaction.hosed == 0
 
     ### More Failure modes...
     # now we mix in some sub transactions
     ###
 
     def testExceptionInSubCommitSub(self):
-        """
-        this tests exhibits some odd behavior,
-        nothing thats technically incorrect...
-
-        basically it seems non deterministic, even
-        stranger the behavior seems dependent on what
-        values i test after the fact... very odd,
-        almost relativistic.
-
-        in-retrospect this is from the fact that
-        dictionaries are used to store jars at some point
-
-        """
+        # It's harder than normal to verify test results, because
+        # the subtransaction jars are stored in a dictionary.  The
+        # order in which jars are processed depends on the order
+        # they come out of the dictionary.
 
         self.sub1.modify()
-
         get_transaction().commit(1)
 
         self.nosub1.modify()
@@ -442,24 +415,30 @@ class TransactionTests(unittest.TestCase):
 
         try:
             get_transaction().commit()
-        except TestTxnException: pass
-
+        except TestTxnException:
+            pass
 
-        # odd this doesn't seem to be entirely deterministic..
         if self.sub1._p_jar.ccommit_sub:
-            assert self.sub1._p_jar.ctpc_abort == 1
+            self.assertEqual(self.sub1._p_jar.ctpc_abort, 1)
         else:
-            assert self.sub1._p_jar.cabort_sub == 1
+            self.assertEqual(self.sub1._p_jar.cabort_sub, 1)
+
+        self.assertEqual(self.sub2._p_jar.ctpc_abort, 1)
+        self.assertEqual(self.nosub1._p_jar.ctpc_abort, 1)
 
         if self.sub3._p_jar.ccommit_sub:
-            assert self.sub3._p_jar.ctpc_abort == 1
+            self.assertEqual(self.sub3._p_jar.ctpc_abort, 1)
         else:
-            assert self.sub3._p_jar.cabort_sub == 1
-
-        assert self.sub2._p_jar.ctpc_abort == 1
-        assert self.nosub1._p_jar.ctpc_abort == 1
+            self.assertEqual(self.sub3._p_jar.cabort_sub, 1)
 
     def testExceptionInSubAbortSub(self):
+        # This test has two errors.  When commit_sub() is called on
+        # sub1, it will fail.  If sub1 is handled first, it will raise
+        # an except and abort_sub() will be called on sub2.  If sub2
+        # is handled first, then commit_sub() will fail after sub2 has
+        # already begun its top-level transaction and tpc_abort() will
+        # be called.
+
         self.sub1._p_jar = SubTransactionJar(errors='commit_sub')
         self.sub1.modify(nojar=1)
         get_transaction().commit(1)
@@ -482,51 +461,47 @@ class TransactionTests(unittest.TestCase):
         # called, then tpc_abort() should be called to abort the
         # actual transaction.  If not, then calling abort_sub() is
         # sufficient.
-        if self.sub3._p_jar.ccommit_sub == 1:
+        if self.sub3._p_jar.ccommit_sub:
             self.assertEqual(self.sub3._p_jar.ctpc_abort, 1)
         else:
             self.assertEqual(self.sub3._p_jar.cabort_sub, 1)
 
     # last test, check the hosing mechanism
 
-    def testHoserStoppage(self):
-        # XXX We should consult ZConfig to decide whether we can get into a
-        # hosed state or not.
-        return
+##    def testHoserStoppage(self):
+##        # It's hard to test the "hosed" state of the database, where
+##        # hosed means that a failure occurred in the second phase of
+##        # the two phase commit.  It's hard because the database can
+##        # recover from such an error if it occurs during the very first
+##        # tpc_finish() call of the second phase.
 
-        # It's hard to test the "hosed" state of the database, where
-        # hosed means that a failure occurred in the second phase of
-        # the two phase commit.  It's hard because the database can
-        # recover from such an error if it occurs during the very first
-        # tpc_finish() call of the second phase.
+##        for obj in self.sub1, self.sub2:
+##            j = HoserJar(errors='tpc_finish')
+##            j.reset()
+##            obj._p_jar = j
+##            obj.modify(nojar=1)
 
-        for obj in self.sub1, self.sub2:
-            j = HoserJar(errors='tpc_finish')
-            j.reset()
-            obj._p_jar = j
-            obj.modify(nojar=1)
+##        try:
+##            get_transaction().commit()
+##        except TestTxnException:
+##            pass
 
-        try:
-            get_transaction().commit()
-        except TestTxnException:
-            pass
+##        self.assert_(Transaction.hosed)
 
-        self.assert_(Transaction.hosed)
+##        self.sub2.modify()
 
-        self.sub2.modify()
-
-        try:
-            get_transaction().commit()
-        except Transaction.POSException.TransactionError:
-            pass
-        else:
-            self.fail("Hosed Application didn't stop commits")
+##        try:
+##            get_transaction().commit()
+##        except Transaction.POSException.TransactionError:
+##            pass
+##        else:
+##            self.fail("Hosed Application didn't stop commits")
 
 
 class DataObject:
 
     def __init__(self, nost=0):
-        self.nost= nost
+        self.nost = nost
         self._p_jar = None
 
     def modify(self, nojar=0, tracing=0):
@@ -543,7 +518,7 @@ class TestTxnException(Exception):
 class BasicJar:
 
     def __init__(self, errors=(), tracing=0):
-        if not isinstance(errors, TupleType):
+        if not isinstance(errors, tuple):
             errors = errors,
         self.errors = errors
         self.tracing = tracing
@@ -557,7 +532,12 @@ class BasicJar:
         self.ccommit_sub = 0
 
     def __repr__(self):
-        return "<jar %X %s>" % (id(self), self.errors)
+        return "<%s %X %s>" % (self.__class__.__name__, id(self), self.errors)
+
+    def sortKey(self):
+        # All these jars use the same sort key, and Python's list.sort()
+        # is stable.  These two
+        return self.__class__.__name__
 
     def check(self, method):
         if self.tracing:
@@ -637,19 +617,19 @@ def test_join():
     transaction.interfaces.IDataManager.
 
     >>> from ZODB.tests.sampledm import DataManager
-    >>> from ZODB.Transaction import DataManagerAdapter
-    >>> t = Transaction.Transaction()
+    >>> from transaction._transaction import DataManagerAdapter
+    >>> t = transaction.Transaction()
     >>> dm = DataManager()
     >>> t.join(dm)
 
     The end result is that a data manager adapter is one of the
     transaction's objects:
 
-    >>> isinstance(t._objects[0], DataManagerAdapter)
+    >>> isinstance(t._resources[0], DataManagerAdapter)
     True
-    >>> t._objects[0]._datamanager is dm
+    >>> t._resources[0]._datamanager is dm
     True
-    
+
     """
 
 def test_suite():

src/ZODB/tests/testZODB.py

@@ -16,8 +16,10 @@ import unittest
 import ZODB
 import ZODB.FileStorage
 from ZODB.POSException import ReadConflictError, ConflictError
+
 from persistent import Persistent
 from persistent.mapping import PersistentMapping
+import transaction
 
 class P(Persistent):
     pass
@@ -54,72 +56,76 @@ class ZODBTests(unittest.TestCase):
         self._db.close()
         self._storage.cleanup()
 
-    def checkExportImport(self, abort_it=0, dup_name='test_duplicate'):
+    def checkExportImport(self, abort_it=False):
         self.populate()
-        get_transaction().begin()
-        get_transaction().note('duplication')
-        # Duplicate the 'test' object.
         conn = self._db.open()
         try:
-            root = conn.root()
-            ob = root['test']
-            assert len(ob) > 10, 'Insufficient test data'
-            try:
-                import tempfile
-                f = tempfile.TemporaryFile()
-                ob._p_jar.exportFile(ob._p_oid, f)
-                assert f.tell() > 0, 'Did not export correctly'
-                f.seek(0)
-                new_ob = ob._p_jar.importFile(f)
-                root[dup_name] = new_ob
-                f.close()
-                if abort_it:
-                    get_transaction().abort()
-                else:
-                    get_transaction().commit()
-            except:
-                get_transaction().abort()
-                raise
+            self.duplicate(conn, abort_it)
         finally:
             conn.close()
-        get_transaction().begin()
-        # Verify the duplicate.
         conn = self._db.open()
         try:
-            root = conn.root()
-            ob = root['test']
-            try:
-                ob2 = root[dup_name]
-            except KeyError:
-                if abort_it:
-                    # Passed the test.
-                    return
-                else:
-                    raise
-            else:
-                if abort_it:
-                    assert 0, 'Did not abort duplication'
-            l1 = list(ob.items())
-            l1.sort()
-            l2 = list(ob2.items())
-            l2.sort()
-            l1 = map(lambda (k, v): (k, v[0]), l1)
-            l2 = map(lambda (k, v): (k, v[0]), l2)
-            assert l1 == l2, 'Duplicate did not match'
-            assert ob._p_oid != ob2._p_oid, 'Did not duplicate'
-            assert ob._p_jar == ob2._p_jar, 'Not same connection'
-            oids = {}
-            for v in ob.values():
-                oids[v._p_oid] = 1
-            for v in ob2.values():
-                assert not oids.has_key(v._p_oid), (
-                    'Did not fully separate duplicate from original')
-            get_transaction().commit()
+            self.verify(conn, abort_it)
         finally:
             conn.close()
 
+    def duplicate(self, conn, abort_it):
+        get_transaction().begin()
+        get_transaction().note('duplication')
+        root = conn.root()
+        ob = root['test']
+        assert len(ob) > 10, 'Insufficient test data'
+        try:
+            import tempfile
+            f = tempfile.TemporaryFile()
+            ob._p_jar.exportFile(ob._p_oid, f)
+            assert f.tell() > 0, 'Did not export correctly'
+            f.seek(0)
+            new_ob = ob._p_jar.importFile(f)
+            self.assertEqual(new_ob, ob)
+            root['dup'] = new_ob
+            f.close()
+            if abort_it:
+                get_transaction().abort()
+            else:
+                get_transaction().commit()
+        except:
+            get_transaction().abort()
+            raise
+
+    def verify(self, conn, abort_it):
+        get_transaction().begin()
+        root = conn.root()
+        ob = root['test']
+        try:
+            ob2 = root['dup']
+        except KeyError:
+            if abort_it:
+                # Passed the test.
+                return
+            else:
+                raise
+        else:
+            self.failUnless(not abort_it, 'Did not abort duplication')
+        l1 = list(ob.items())
+        l1.sort()
+        l2 = list(ob2.items())
+        l2.sort()
+        l1 = map(lambda (k, v): (k, v[0]), l1)
+        l2 = map(lambda (k, v): (k, v[0]), l2)
+        self.assertEqual(l1, l2)
+        self.assert_(ob._p_oid != ob2._p_oid)
+        self.assertEqual(ob._p_jar, ob2._p_jar)
+        oids = {}
+        for v in ob.values():
+            oids[v._p_oid] = 1
+        for v in ob2.values():
+            assert not oids.has_key(v._p_oid), (
+                'Did not fully separate duplicate from original')
+        get_transaction().commit()
+
     def checkExportImportAborted(self):
-        self.checkExportImport(abort_it=1, dup_name='test_duplicate_aborted')
+        self.checkExportImport(abort_it=True)
 
     def checkVersionOnly(self):
         # Make sure the changes to make empty transactions a no-op
@@ -160,6 +166,44 @@ class ZODBTests(unittest.TestCase):
         conn._setDB(self._db)  # simulate the connection being reopened
         self.assertEqual(len(conn._cache), 0)
 
+    def checkExplicitTransactionManager(self):
+        # Test of transactions that apply to only the connection,
+        # not the thread.
+        tm1 = transaction.TransactionManager()
+        conn1 = self._db.open(txn_mgr=tm1)
+        tm2 = transaction.TransactionManager()
+        conn2 = self._db.open(txn_mgr=tm2)
+        try:
+            r1 = conn1.root()
+            r2 = conn2.root()
+            if r1.has_key('item'):
+                del r1['item']
+                tm1.get().commit()
+            r1.get('item')
+            r2.get('item')
+            r1['item'] = 1
+            tm1.get().commit()
+            self.assertEqual(r1['item'], 1)
+            # r2 has not seen a transaction boundary,
+            # so it should be unchanged.
+            self.assertEqual(r2.get('item'), None)
+            conn2.sync()
+            # Now r2 is updated.
+            self.assertEqual(r2['item'], 1)
+
+            # Now, for good measure, send an update in the other direction.
+            r2['item'] = 2
+            tm2.get().commit()
+            self.assertEqual(r1['item'], 1)
+            self.assertEqual(r2['item'], 2)
+            conn1.sync()
+            conn2.sync()
+            self.assertEqual(r1['item'], 2)
+            self.assertEqual(r2['item'], 2)
+        finally:
+            conn1.close()
+            conn2.close()
+
     def checkLocalTransactions(self):
         # Test of transactions that apply to only the connection,
         # not the thread.

src/ZODB/tests/testmvcc.py

@@ -41,8 +41,9 @@ We will use two different connections with the experimental
 setLocalTransaction() method to make sure that the connections act
 independently, even though they'll be run from a single thread.
 
->>> cn1 = db.open()
->>> txn1 = cn1.setLocalTransaction()
+>>> import transaction
+>>> tm1 = transaction.TransactionManager()
+>>> cn1 = db.open(txn_mgr=tm1)
 
 The test will just use some MinPO objects.  The next few lines just
 setup an initial database state.
@@ -51,12 +52,12 @@ setup an initial database state.
 >>> r = cn1.root()
 >>> r["a"] = MinPO(1)
 >>> r["b"] = MinPO(1)
->>> txn1.commit()
+>>> tm1.get().commit()
 
 Now open a second connection.
 
->>> cn2 = db.open()
->>> txn2 = cn2.setLocalTransaction()
+>>> tm2 = transaction.TransactionManager()
+>>> cn2 = db.open(txn_mgr=tm2)
 
 Connection high-water mark
 --------------------------
@@ -104,7 +105,7 @@ will modify "a."  The other transaction will then modify "b" and commit.
 
 >>> r1 = cn1.root()
 >>> r1["a"].value = 2
->>> cn1.getTransaction().commit()
+>>> tm1.get().commit()
 >>> txn = db.lastTransaction()
 
 The second connection has its high-water mark set now.
@@ -141,7 +142,7 @@ It's possible to modify "a", but we get a conflict error when we
 commit the transaction.
 
 >>> r2["a"].value = 3
->>> txn2.commit()
+>>> tm2.get().commit()
 Traceback (most recent call last):
  ...
 ConflictError: database conflict error (oid 0000000000000001, class ZODB.tests.MinPO.MinPO)
@@ -155,9 +156,7 @@ None
 
 >>> r1 = cn1.root()
 >>> r1["a"].value = 3
->>> txn1 is cn1.getTransaction()
-True
->>> cn1.getTransaction().commit()
+>>> tm1.get().commit()
 >>> txn = db.lastTransaction()
 >>> cn2._txn_time == txn
 True
@@ -165,7 +164,7 @@ True
 >>> r2["b"].value = r2["a"].value + 1
 >>> r2["b"].value
 3
->>> txn2.commit()
+>>> tm2.get().commit()
 >>> print cn2._txn_time
 None
 
@@ -185,7 +184,7 @@ First get the database back in an initial state.
 >>> cn1.sync()
 >>> r1["a"].value = 0
 >>> r1["b"].value = 0
->>> cn1.getTransaction().commit()
+>>> tm1.get().commit()
 
 >>> cn2.sync()
 >>> r2["a"].value
@@ -206,7 +205,7 @@ should all have the same effect on non-current objects in cache.
 ...     cn1.sync()
 ...     r1["a"].value = 0
 ...     r1["b"].value = 0
-...     cn1.getTransaction().commit()
+...     tm1.get().commit()
 ...     cn2.sync()
 ...     r2["b"].value = 1
 ...     cn2.getTransaction().commit()
@@ -217,7 +216,7 @@ should all have the same effect on non-current objects in cache.
 >>> r1["b"].value
 0
 >>> r1["a"].value = 1
->>> cn1.getTransaction().commit()
+>>> tm1.get().commit()
 >>> r1["b"]._p_state
 -1
 
@@ -280,14 +279,13 @@ non-current revision to load.
 
 >>> ts = TestStorage()
 >>> db = DB(ts)
->>> cn1 = db.open()
->>> txn1 = cn1.setLocalTransaction()
+>>> cn1 = db.open(txn_mgr=tm1)
 >>> r1 = cn1.root()
 >>> r1["a"] = MinPO(0)
 >>> r1["b"] = MinPO(0)
->>> cn1.getTransaction().commit()
+>>> tm1.get().commit()
 >>> r1["b"].value = 1
->>> cn1.getTransaction().commit()
+>>> tm1.get().commit()
 >>> cn1.cacheMinimize()  # makes everything in cache a ghost
 
 >>> oid = r1["b"]._p_oid
@@ -318,12 +316,11 @@ activate "b" will result in a ReadConflictError.
 
 >>> ts = TestStorage()
 >>> db = DB(ts)
->>> cn1 = db.open()
->>> txn1 = cn1.setLocalTransaction()
+>>> cn1 = db.open(txn_mgr=tm1)
 >>> r1 = cn1.root()
 >>> r1["a"] = MinPO(0)
 >>> r1["b"] = MinPO(0)
->>> cn1.getTransaction().commit()
+>>> tm1.get().commit()
 >>> cn1.cacheMinimize()  # makes everything in cache a ghost
 
 >>> oid = r1["b"]._p_oid

src/transaction/README.txt

@@ -11,3 +11,4 @@ is syntactically simple, but semantically complex.  The semantics
 were not easy to express in the interface. This could probably use
 more work.  The semantics are presented in detail through examples of
 a sample data manager in transaction.tests.test_SampleDataManager.
+

src/transaction/__init__.py

@@ -12,5 +12,22 @@
 #
 ############################################################################
 
-from ZODB.Transaction import get_transaction
+from transaction._transaction import Transaction
+from transaction._manager import TransactionManager, ThreadTransactionManager
 
+manager = ThreadTransactionManager()
+
+def get():
+    return manager.get()
+
+def begin():
+    return manager.begin()
+
+def commit():
+    manager.get().commit()
+
+def abort():
+    manager.get().abort()
+
+# XXX Issue deprecation warning if this variant is used?
+get_transaction = get

src/transaction/_manager.py

+############################################################################
+#
+# Copyright (c) 2004 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.
+#
+############################################################################
+"""A TransactionManager controls transaction boundaries.
+
+It coordinates application code and resource managers, so that they
+are associated with the right transaction.
+"""
+
+import thread
+
+from transaction._transaction import Transaction
+
+class TransactionManager(object):
+
+    def __init__(self):
+        self._txn = None
+        self._synchs = []
+
+    def begin(self):
+        if self._txn is not None:
+            self._txn.abort()
+        self._txn = Transaction(self._synchs, self)
+        return self._txn
+
+    def get(self):
+        if self._txn is None:
+            self._txn = Transaction(self._synchs, self)
+        return self._txn
+
+    def free(self, txn):
+        assert txn is self._txn
+        self._txn = None
+
+    def registerSynch(self, synch):
+        self.synchs.append(synch)
+
+    def unregisterSynch(self, synch):
+        self._synchs.remove(synch)
+
+class ThreadTransactionManager(object):
+    """Thread-aware transaction manager.
+
+    Each thread is associated with a unique transaction.
+    """
+
+    def __init__(self):
+        # _threads maps thread ids to transactions
+        self._txns = {}
+        # _synchs maps a thread id to a list of registered synchronizers.
+        # The list is passed to the Transaction constructor, because
+        # it needs to call the synchronizers when it commits.
+        self._synchs = {}
+
+    def begin(self):
+        tid = thread.get_ident()
+        txn = self._txns.get(tid)
+        if txn is not None:
+            txn.abort()
+        txn = self._txns[tid] = Transaction(self._synchs.get(tid), self)
+        return txn
+
+    def get(self):
+        tid = thread.get_ident()
+        txn = self._txns.get(tid)
+        if txn is None:
+            txn = self._txns[tid] = Transaction(self._synchs.get(tid), self)
+        return txn
+
+    def free(self, txn):
+        tid = thread.get_ident()
+        assert txn is self._txns.get(tid)
+        del self._txns[tid]
+
+    def registerSynch(self, synch):
+        tid = thread.get_ident()
+        L = self._synchs.setdefault(tid, [])
+        L.append(synch)
+
+    def unregisterSynch(self, synch):
+        tid = thread.get_ident()
+        L = self._synchs.get(tid)
+        L.remove(synch)
+

src/transaction/tests/test_register_compat.py

+##############################################################################
+#
+# Copyright (c) 2004 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.
+#
+##############################################################################
+"""Test backwards compatibility for resource managers using register().
+
+The transaction package supports several different APIs for resource
+managers.  The original ZODB3 API was implemented by ZODB.Connection.
+The Connection passed persistent objects to a Transaction's register()
+method.  It's possible that third-party code also used this API, hence
+these tests that the code that adapts the old interface to the current
+API works.
+
+These tests use a TestConnection object that implements the old API.
+They check that the right methods are called and in roughly the right
+order.
+
+Common cases
+------------
+
+First, check that a basic transaction commit works.
+
+>>> cn = TestConnection()
+>>> cn.register(Object())
+>>> cn.register(Object())
+>>> cn.register(Object())
+>>> transaction.commit()
+>>> len(cn.committed)
+3
+>>> len(cn.aborted)
+0
+>>> cn.calls
+['begin', 'vote', 'finish']
+
+Second, check that a basic transaction abort works.  If the
+application calls abort(), then the transaction never gets into the
+two-phase commit.  It just aborts each object.
+
+>>> cn = TestConnection()
+>>> cn.register(Object())
+>>> cn.register(Object())
+>>> cn.register(Object())
+>>> transaction.abort()
+>>> len(cn.committed)
+0
+>>> len(cn.aborted)
+3
+>>> cn.calls
+[]
+
+Error handling
+--------------
+
+The tricky part of the implementation is recovering from an error that
+occurs during the two-phase commit.  We override the commit() and
+abort() methods of Object to cause errors during commit.
+
+Note that the implementation uses lists internally, so that objects
+are committed in the order they are registered.  (In the presence of
+multiple resource managers, objects from a single resource manager are
+committed in order.  The order of resource managers depends on
+sortKey().)  I'm not sure if this is an accident of the implementation
+or a feature that should be supported by any implementation.
+
+>>> cn = TestConnection()
+>>> cn.register(Object())
+>>> cn.register(CommitError())
+>>> cn.register(Object())
+>>> transaction.commit()
+Traceback (most recent call last):
+ ...
+RuntimeError: commit
+>>> len(cn.committed)
+1
+>>> len(cn.aborted)
+2
+
+"""
+
+import transaction
+
+class Object(object):
+
+    def commit(self):
+        pass
+
+    def abort(self):
+        pass
+
+class CommitError(Object):
+
+    def commit(self):
+        raise RuntimeError("commit")
+
+class AbortError(Object):
+
+    def abort(self):
+        raise RuntimeError("abort")
+
+class BothError(CommitError, AbortError):
+    pass
+
+class TestConnection:
+
+    def __init__(self):
+        self.committed = []
+        self.aborted = []
+        self.calls = []
+
+    def register(self, obj):
+        obj._p_jar = self
+        transaction.get().register(obj)
+
+    def sortKey(self):
+        return str(id(self))
+
+    def tpc_begin(self, txn, sub):
+        self.calls.append("begin")
+
+    def tpc_vote(self, txn):
+        self.calls.append("vote")
+
+    def tpc_finish(self, txn):
+        self.calls.append("finish")
+
+    def tpc_abort(self, txn):
+        self.calls.append("abort")
+
+    def commit(self, obj, txn):
+        obj.commit()
+        self.committed.append(obj)
+
+    def abort(self, obj, txn):
+        obj.abort()
+        self.aborted.append(obj)
+
+import doctest
+
+def test_suite():
+    return doctest.DocTestSuite()