def checkpoint(self, name):
""" to be used with with_statement.
with stream.checkpoint():
stream.next()
stream.peek(0)
raise Foo
will automatically roll back the stream for you upon exception.
will eat the exception.
"""
depth = len(self.checkpoints)
if DEBUG:
if STEP:
import pdb; pdb.set_trace()
print " BEGIN _________________________%s%s" % ('| '*depth, name)
print str(self)
context_id = randid()
self.checkpoints.append( (context_id, []) ) # the 'next' method will append to this list
try:
yield context_id
except ParseError, e:
# unroll
last_checkpoint = self.checkpoints.pop()
assert last_checkpoint[0] == context_id, "oops, control stack got borked. did you mess with rollback checkpoints? expected %s but got %s" % (context_id, last_checkpoint[0])
self.push_back_tokens = last_checkpoint[1] + self.push_back_tokens
if DEBUG:
print " ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~%s%s %s %s" % ('| '*depth, name, 'FAIL', e.message)
def register(self, id, timeout, callable, *vargs, **kwargs): with self.__lock_expiration: # should the alarm thread be sleeping, we wake it up. with self.__cond_alarm_sleep: self.__cond_alarm_sleep.notifyAll() # push the new alarm_item to the heap now = time.time() tix = "tix" + randid() heapq.heappush(self.expiration_heap, (now + timeout, id, tix, callable, vargs, kwargs) ) self.expiration_tix_lookup[id] = tix