def purge_revision(self, revision, leave_record=False):
'''Purge all changes associated with a revision.
@param leave_record: if True leave revision in existence but change message
to "PURGED: {date-time-of-purge}". If false delete revision object as
well.
Summary of the Algorithm
------------------------
1. list all RevisionObjects affected by this revision
2. check continuity objects and cascade on everything else ?
1. crudely get all object revisions associated with this
2. then check whether this is the only revision and delete the
continuity object
3. ALTERNATIVELY delete all associated object revisions then do a
select on continutity to check which have zero associated revisions
(should only be these ...)
'''
logger.debug('Purging revision: %s' % revision.id)
to_purge = []
SQLAlchemySession.setattr(self.session, 'revisioning_disabled', True)
self.session.autoflush = False
for o in self.versioned_objects:
revobj = o.__revision_class__
items = self.session.query(revobj).filter_by(
revision=revision).all()
for item in items:
continuity = item.continuity
if continuity.revision == revision: # need to change continuity
trevobjs = self.session.query(revobj).join(
'revision').filter(
revobj.continuity == continuity).order_by(
Revision.timestamp.desc()).limit(2).all()
if len(trevobjs) == 0:
raise Exception('Should have at least one revision.')
if len(trevobjs) == 1:
to_purge.append(continuity)
else:
new_correct_revobj = trevobjs[1] # older one
self.revert(continuity, new_correct_revobj)
# now delete revision object
self.session.delete(item)
for cont in to_purge:
self.session.delete(cont)
if leave_record:
import datetime
revision.message = u'PURGED: %s UTC' % datetime.datetime.utcnow()
else:
self.session.delete(revision)
self.commit_and_remove()
def new_revision(self):
'''Convenience method to create new revision and set it on session.
NB: if in transactional mode do *not* need to call `begin` as we are
automatically within a transaction at all times if session was set up
as transactional (every commit is paired with a begin)
<http://groups.google.com/group/sqlalchemy/browse_thread/thread/a54ce150b33517db/17587ca675ab3674>
'''
rev = Revision()
self.session.add(rev)
SQLAlchemySession.set_revision(self.session, rev)
return rev
def new_revision(self):
'''Convenience method to create new revision and set it on session.
NB: if in transactional mode do *not* need to call `begin` as we are
automatically within a transaction at all times if session was set up
as transactional (every commit is paired with a begin)
<http://groups.google.com/group/sqlalchemy/browse_thread/thread/a54ce150b33517db/17587ca675ab3674>
'''
rev = Revision()
self.session.add(rev)
SQLAlchemySession.set_revision(self.session, rev)
return rev
def purge_revision(self, revision, leave_record=False):
'''Purge all changes associated with a revision.
@param leave_record: if True leave revision in existence but change message
to "PURGED: {date-time-of-purge}". If false delete revision object as
well.
Summary of the Algorithm
------------------------
1. list all RevisionObjects affected by this revision
2. check continuity objects and cascade on everything else ?
1. crudely get all object revisions associated with this
2. then check whether this is the only revision and delete the
continuity object
3. ALTERNATIVELY delete all associated object revisions then do a
select on continutity to check which have zero associated revisions
(should only be these ...)
'''
logger.debug('Purging revision: %s' % revision.id)
to_purge = []
SQLAlchemySession.setattr(self.session, 'revisioning_disabled', True)
self.session.autoflush = False
for o in self.versioned_objects:
revobj = o.__revision_class__
items = self.session.query(revobj).filter_by(revision=revision).all()
for item in items:
continuity = item.continuity
if continuity.revision == revision: # need to change continuity
trevobjs = self.session.query(revobj).join('revision'). filter(
revobj.continuity==continuity
).order_by(Revision.timestamp.desc()).limit(2).all()
if len(trevobjs) == 0:
raise Exception('Should have at least one revision.')
if len(trevobjs) == 1:
to_purge.append(continuity)
else:
new_correct_revobj = trevobjs[1] # older one
self.revert(continuity, new_correct_revobj)
# now delete revision object
self.session.delete(item)
for cont in to_purge:
self.session.delete(cont)
if leave_record:
import datetime
revision.message = u'PURGED: %s UTC' % datetime.datetime.utcnow()
else:
self.session.delete(revision)
self.commit_and_remove()
