thread, instead of doing it every nth ZODB transaction.  We can
actually provide a base class for both the checkpointing and
autopacking threads here.  Changes here include:

SLEEP_TIME: how often (in seconds) a background thread should wake up
to see if there's work to do.

True, False: Add these for older Pythons.

PackStop: New class that acts as an escape hatch for pack operations.

BerkeleyConfig:
    - change interval from 100 to 0.  Now that this controls the
      checkpointing thread, the current default is to not spawn the
      thread.  I'm probably going to change this once I figure out
      what a good value is.

BerkeleyBase:
    - __init__(): Start the checkpointing thread if interval > 0

    - _setupDB(): Add some additional keyword args so that the QUEUE
      style tables can use this convenience method too.

    - close(): Be sure to stop and join the checkpointing thread

    - _docheckpoint(): Removed

    - _withtxn(): Catch PackStop escape hatch exceptions.  This one
      aborts the current Berkeley transaction but eats the exception.
      Also, don't call _docheckpoint() here.

     - docheckpoint(): New method which the checkpointing threads can
       call.

env_from_string(): use DB_RECOVER_FATAL for autorecovery on open.

_WorkThread: New base class for the checkpointing and autopacking
threads.

_CheckPoint: The common checkpointing thread class.

Also perform whitespace normalization on cvs log comment.

parent to allow the parent to acquire things like CMF tools during lookup.
Note that this relies on the unwritten assumption that __getitem__ will not
acquire things as getattr will.

method which is required by recovery.  We can initialize the last tid
from the txnoids table, and then keep it updated in _finish().

sense for Berkeley storages.

Update information about the version of Python required -- Python
2.2.2 fixed a bug that seriously affected some Zope installations that
used 2.2.1.

Update information about the version of Python required -- the trunk
is now in the new world (by Papal edict; don't shoot the messenger!).

for an object revision in objrevs got collected away when the entire
object was refcounted to zero.  Be more defensive about find and
deleting these records.

Also, truncate the packtime table before writing the new record, to
maintain the database invariant that there is only allowed one entry
in this table at a time.

*first* entry (and not the last one as assumed before).

- Adjust test to create a big file that will have a Pdata entry of smaller
  size

- Fix pdata_map lookups with first-entry-size in mind.

Remove unnecessary Py_FatalError() calls on failed module import.

Merged remaining changes from toby-clean-shutdown-branch. This resolves the overnight problem where storages were not closed if Zope is shut down using the ZMI, and the long-standing problem where storages were closed too soon when shut down using a signal

        the Zope profiling support

#include <string.h> is implied by ExtensionClass.h, because it includes
Python.h.  Also, it is an error to include standard headers before
Python.h.

#include <stdio.h> is implied by ExtensionClass.h, because it includes
Python.h.  Also, it is an error to include standard headers before
Python.h.

Bugfix candidate.

dont close the storages mid-transaction. need to check whether we need to close them at the end of z2.py

New `catdel' command which deletes the entire catalog in one
transaction.

Add a new global VERBOSE flag instead of passing around the printstat
argument everywhere.  This also lets us use getopt for proper option
parsing, and add a -v/--verbose flag for setting that global.

Added a usage() function.

two values are tainted failed because no implicit conversion to a list took
place.

between objects which are unreachable from the root -- and thus might
be collected by autopack -- and cycles which are unreachable from the
root -- which can only be collected by a full pack.

cycle deletion tests.

collect cycles.

Also, some code updating and re-org to factor code into the base
class.

_dostore(): Support conflict resolution.

__init__(), _withtxn(): Removed.

_decrefPickle(): Fixed a typo.

BerkeleyConfig: Clarify in the docstring the semantics of the various
autopack variables, w.r.t. the differences between Full and Minimal
autopacking (the latter always does a gc pack because there's nothing
else it /could/ do :).

__init__(): We can create the packlock here, allowing us to get rid of
the __init__'s in the derived classes.

_withtxn(): Turns out to be useful for both storages.

ThreadedAsync/LoopCallback.py: when select() is interrupted by a
signal handler, don't attempt to read all file descriptors.

in the setup.py script.