This changes the behavior slightly for invalidations.  A Connection
will receive invalidations even if it didn't have any modified objects
in the transaction, e.g. db.undo() or a read-only transaction.  For
this to work, it assumes that the thread that called db.open() is the
thread that is going to use the connection.  If this isn't true, the
synch argument to db.open() can be used to disable the new feature.

note the different default hostname for an inet-address on Windows and Unix

ZServer package.

aren't needed any more

is an API shim to the logging module.  No more competing initializations!

implementation.  The configuration aspects of zLOG are about to disappear.

can import just one of eventlog and logger if desired.  This is needed for
Zope 2 to allow the main Zope configuration to only use eventlog, since the
name "logger" is used for something else.

think they're allowed to do it.  For now, just let zLOG initialize
everything; we can figure out the right way to make zLOG and logging
co-habitate later.

- don't dump everything into the "event" logger;
  use the subsystem argument to zLOG.LOG to get a specific logger
- move some comments into docstrings

constructor (potentially) changes the directory

places.

be done as late as possible (if ever)

DB._closeConnection() sets the connection's _db member to None now, under
protection of the lock it holds anyway.  At a deeper level, it's unclear
why _db keeps getting set and unset to begin with, but no time for that
now (and there are already XXX comments about it in the code).

Alas, I wasn't able to write a test that provoked the original bug in
finite time (it's a tiny timing hole), except via calling sleep() between
two lines that don't exist anymore.  Good enough.

an object as a non-negative integer.  Code trying to pass addresses to
an %x format uses positive_id(), and this avoids a Python FutureWarning
about applying %x to negative ints.  The primary difference between this
and the last stab is that positive_id() should work OK on 64-bit boxes
too.  What we really want here is C's %p format code, but in Python we
can't even reliably know the width of native addresses.

negative ints *as* negative ints when fed into %x formats.  Python 2.3
still renders them as positive ints, but spews

FutureWarning: %u/%o/%x/%X of negative int will return a signed string
               in Python 2.4 and up

to warn about the impending change.  Jim reported two instances of that
warning when running the tests on a box where addresses happen to "be
negative".  So make the addresses look positive instead (2.3 and 2.4
treat those the same, so 2.3 doesn't warn about those).

Problem:  it occurs to me now that I'm assuming addresses fit in 32
bits here.

the former, remember it and raise it after calling _cleanup.  If
abort_sub() or tpc_abort() in _cleanup() also raise exceptions, log
them but don't propagate them.

This stops stray output produced by tests testExceptionInTpcAbort and
testExceptionInSubAbortSub.

Grrrrr:  I haven't yet been able to figure out how to get logging to work
in ZODB, so haven't yet been able to check that the new logging is
reasonable.

import here wasn't changed to track it.  Repaired.

get_transaction() is still stuffed into __builtin__ as a magical side
effect of importing ZODB.

testExceptionInTpcAbort().  The cause is clear now, but a solution isn't;
an exception in tpc_abort is nasty.

(something's not right in this test).

taught about the new "transaction" package.

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.

of pack in buffered mode, then switching to unbuffered mode to copy the
tail, actually broke pack completely on Windows:  we didn't close the
buffered file handle before opening the unbuffered one, and self.gc held
on to the still-open former handle.  This prevented the caller from
renaming Data.fs to Data.fs.old (a handle on Data.fs was still open).
The cure is simply to close a handle when we stop using it.

Only open the file for unbuffered I/O after finishing the first phase
of pack.  The first phase gets its end-of-file position from the main
thread, so there's no possibility of reading a 'c' record.

Timings on Linux are inconclusive, but it seems like using buffered
I/O for the initial phase should be faster.

Provide a way to shutdown the servers using an exit status.