savepoint support ?

[jvanasco]

is there any reason for the lack of savepoint support , other than it not being in zope.sendmail ? [ ie, does anyone know why it's not in zope.sendmail ? ]

i've been working on trying to patch this for savepoint support , and would appreciate any pointers.

[jvanasco]

this took a few more hours than expected, but I seem to have gotten savepoint support in here:

jvanasco@06ad882

It passes tests and doesn't break any tests, but definitely needs use more eyes on it as I restructured some things ( and am not all that happy with this ; it was a crash course on learning transaction ).

Notes:

• I added a DEBUG_FLOW boolean variable on line 39 of delivery.py to print out the def name and tpc info ; it's really useful when trying to map out the correct flow of multiple savepoints
• there's a class of MaiDataManagerState codes. i tried to model everything between the zope.sqlalchemy and the sample transaction support in transaction ; a lot of this is not used and it all might be not needed.
• i tried to wrap everything in a check for is_resource_in_transaction. i originally didn't notice that the AbstractMailDelivery.send function was wrapped in a transaction.join(). i split that into 2 lines on the send, and called a new join_transaction function.
• I have abort_sub and commit_sub raise ValueErrors. I haven't been able to trigger these.
• calls to abort have some quick assertion checks, and call an internal _resetTransaction function before the specified onAbort function
• the _resetTransaction and _finish functions could probably go

[jvanasco]

I'm closing this request in favor of #24