Once we start using savepoints, we need to make sure that all data are
committed through the savepoints. Otherwise, things can get committed
in the wrong order, leading to conflicts.

savepoint, then modified and then aborted.

Also added missing code to clear registered objects when a savepoint
was rolled back.

(And also added interfaces and rearranged some code to hopefully make
it easier to read.)

Also fiddled things to make this look like release 3.4a4.

In addition, repaired the useless default logging in runzeo.py.

Here's Sidnei's Zope 2.7 checkin comment:

* Borrow Zope's 'Signal' mechanism for Windows, if available, to
  implement clean shutdown and log rotation handlers for Windows.

* Back to creating a .PID for ZEO, so external programs that wish to set
  the 'signal' can get the PID and therefore derive the signal name.
  Currently only necessary on Windows but created on all platforms which
  implement os.getpid(), as long as the 'pid-filename' option is set,
  or the 'INSTANCE_HOME' environment variable can be found.

DemoStorage:  Added implementations for registerDB() and new_oid().  As
Tres discovered the hard way, wrapping a ZEO client storage as a
DemoStorage base storage yields insane behavior otherwise.

BaseStorage.new_oid():  Rewrite to eliminate recursion, and hence also the
need for the undocumented and irregular `last=` argument.

Other:  removed the `last=` argument to new_oid() every place that felt
compelled to spread that insanity ;-).  Seriously, it served no purpose
at all elsewhere, and looks like people just cut 'n pasted in fear.

for Zope3 and Zope trunk development to use.

The test didn't work if run more than once (e.g., via Zope3's
 test.py's "-N <n>" argument, or via ZODB's test.py's "-L"
argument), because the warnings module suppresses warnings
after the first a single line.  Made the warnings module
report repeats of DeprecationWarnings for the duration of
the test.

This is Florent Guillaume's branch, giving transaction objects
a new beforeCommitHook() method, as proposed by Jim Fulton on
zodb-dev.  Some changes were made to the branch code (comments,
more tests, more words in the docs).

This doesn't have a lot of visible effect on standalone ZODB use, but
is important for Zope 2.8.

Here are checkin msgs from the branch relating to ZODB code:

    r29872 | jim | 2005-04-04 07:04:39 -0400 (Mon, 04 Apr 2005) | 3 lines
    Changed paths:
       M /Zope/branches/jim-fix-zclasses/lib/python/ZODB/serialize.py

    For instances of persistent classes, save a class-module/clas-name
    tuple if the class has a non-empty module string.

    ------------------------------------------------------------------------
    r29871 | jim | 2005-04-04 07:04:33 -0400 (Mon, 04 Apr 2005) | 6 lines
    Changed paths:
       M /Zope/branches/jim-fix-zclasses/lib/python/ZODB/Connection.py

    Changed sub-transaction abort code to not invalidate created objects.
    There's really no point, because created objects will be unreachable
    after invalidating old objects.  Also, if a created object is
    non-ghostifiable, it will try to load it's state again, and then
    either it would fail or it would load non-committed state.

    ------------------------------------------------------------------------
    r29870 | jim | 2005-04-04 07:04:27 -0400 (Mon, 04 Apr 2005) | 3 lines
    Changed paths:
       A /Zope/branches/jim-fix-zclasses/lib/python/ZODB/persistentclass.py
       A /Zope/branches/jim-fix-zclasses/lib/python/ZODB/persistentclass.txt
       A /Zope/branches/jim-fix-zclasses/lib/python/ZODB/tests/testpersistentclass.py

    Added ZClass-independent test of (and possible base class for)
    persistent-class support machinery.

    ------------------------------------------------------------------------
    r29867 | jim | 2005-04-04 07:03:48 -0400 (Mon, 04 Apr 2005) | 2 lines
    Changed paths:
       M /Zope/branches/jim-fix-zclasses/lib/python/transaction/_manager.py

    Added missing arguments to commit and abort.

    ------------------------------------------------------------------------
    r29774 | jim | 2005-04-01 06:24:27 -0500 (Fri, 01 Apr 2005) | 3 lines
    Changed paths:
       M /Zope/branches/jim-fix-zclasses/lib/python/transaction/__init__.py

    Changed to use methods of a threaded manager directly, rather than
    through wrapper functions.

    ------------------------------------------------------------------------
    r29773 | jim | 2005-04-01 06:24:25 -0500 (Fri, 01 Apr 2005) | 3 lines
    Changed paths:
       M /Zope/branches/jim-fix-zclasses/lib/python/transaction/_manager.py

    Added commit and abort methods to transaction managers.
    This makes direcr use of managers simpler.

    ------------------------------------------------------------------------
    r29101 | jim | 2005-02-10 07:44:52 -0500 (Thu, 10 Feb 2005) | 2 lines
    Changed paths:
       M /Zope/branches/jim-fix-zclasses/lib/python/ZODB/Connection.py

    Removed an unused attribute.

    ------------------------------------------------------------------------
    r29100 | jim | 2005-02-10 07:42:35 -0500 (Thu, 10 Feb 2005) | 3 lines
    Changed paths:
       M /Zope/branches/jim-fix-zclasses/lib/python/transaction/_transaction.py

    Changed an XXX comment to an ordinary comment, explaining the relevent
    issue.

    ------------------------------------------------------------------------
    r29099 | jim | 2005-02-10 07:41:58 -0500 (Thu, 10 Feb 2005) | 3 lines
    Changed paths:
       M /Zope/branches/jim-fix-zclasses/lib/python/ZODB/Connection.py

    Changed some XXX comments to ordinary comments explaining the relevent
    issues.

    ------------------------------------------------------------------------
    r29071 | jim | 2005-02-07 07:36:05 -0500 (Mon, 07 Feb 2005) | 3 lines
    Changed paths:
       M /Zope/branches/jim-fix-zclasses/lib/python/transaction/_transaction.py

    Added a sanity check to avoid registration of objects without a
    manager. (Perhaps this should be an assert.)

    ------------------------------------------------------------------------
    r29067 | jim | 2005-02-07 07:35:56 -0500 (Mon, 07 Feb 2005) | 15 lines
    Changed paths:
       M /Zope/branches/jim-fix-zclasses/lib/python/ZODB/Connection.py

    Changed the strategy for handling invalidation of classes.
    No-longer use setklassstate.  Instead, just call _p_invalidate, as
    with any other object.  This changes didn't break any tests, so I
    assume that this was untested. :(

    Changed the strategy for invalidating objects.  Non-ghostifiable
    objects will load their state when they are invalidated.  We have to
    worry about other invalidations that come in while this is happening.
    See the comment in _flush_invalidations.

    We need to force all invalidations to take this into account, by going
    through _flush_invalidations.  I haven't done this yet, but I have
    left some XXX comments in places where it needs to be done to remind
    myself that this needs to be done.

    ------------------------------------------------------------------------
    r29066 | jim | 2005-02-07 07:35:54 -0500 (Mon, 07 Feb 2005) | 8 lines
    Changed paths:
       M /Zope/branches/jim-fix-zclasses/lib/python/persistent/cPickleCache.c

    Changed the strategy for handling invalidation of classes.
    No-longer use setklassstate.  Instead, just call _p_invalidate, as
    with any other object.  This changes didn't break any tests, so I
    assume that this was untested. :(

    Change invalidation to not swallow errors. (Swallowing errors here was a
    travesty!)

Port from Zope 2.7 branch.

The various flavors of the ``check2ZODBThreads`` and ``check7ZODBThreads``
tests are much less likely to suffer sproadic failures now.

Since ZODB needs to work with Zope trunk, keeping this dependence
in synch is important.

Zope trunk gets it.

development get a release tag to use.

The Persistence module no longer exists in Zope3's idea of what
ZODB is, but this test relies on it.  Make it tolerate the
absence of Persistence.

(backported from trunk revisions 29818 and 29819)

Noet that the URL doesn't exist yet.

The ZODB trunk is for 3.5 now.

This is news about ZEO protocol changes.  The promised
update of README.txt will have to be rewritten from
scratch for 3.4 (the new text in 3.3's README.txt isn't
quite right for the 3.4 release).

Rewrite ZEO protocol negotiation.

3.3 should have bumped the ZEO protocol number (new methods were
added for MVCC support), but didn't.  Untangling this is a mess.

the most common cases (commit() and abort()) -- it's not really
obvious that shortcut spelling exist for those.

Merge checkin made from a wrong project.

Believe it or not, ZopeUndo is ZEO code, not Zope code.

r29726 | slinkp | 2005-03-30 02:11:22 -0500 (Wed, 30 Mar 2005) | 3 lines
Changed paths:
   M /Zope/trunk/lib/python/ZopeUndo/Prefix.py
   M /Zope/trunk/lib/python/ZopeUndo/tests/testPrefix.py

Merged slinkp_1726_zopeundo: avoid showing undo transactions in
the wrong folder.

This always slept for 3 seconds, waiting for the storage to
disconnect.  This loses on two counts:

1. Since the timeout is set to 1 second, it typically sleeps
   longer than necessary.

2. Since there's no predicting thread and process scheduling,
   3 seconds isn't always long enough, and rare failures have
   been reported against this test.

Instead we do a polling loop now.  This typically succeeds in
a little more than a second, speeding the normal case.  The
loop will continue trying for up to a minute if not.

Change default port # from 9999 to 8100, to match zope.conf
(well, on Zope trunk anyway -- the ZEO client example appears
to have gone missing from zope.conf on Zope3 trunk).

s/zeo/ZEO/ in logger name, to match other ZEO logger names.

Collector #1734.  Critical bug in BTree conflict resolution.

Stop silent data loss in some BTree cases where a transaction adds
a new key to a bucket while a concurrent transaction deletes all
keys from the same bucket.

Still needs porting to 3.2 line.