def Execute(self, operation_id=None, wait_callback=None):
"""Starts execution of all operations for the managed user. Once all operations have been
completed, or if another server is already executing the operations, then the callback
passed to __init__ is invoked. If the "operation_id" argument is provided, it is used as a
hint as to where to start execution. However, if an operation with a lower id is found in
the database, that is executed first, in order to ensure that the server executes operations
in the same order that a device submitted them. If "wait_callback" is specified, then it is
invoked when the "operation_id" operation is complete (but other operations for the user may
still be running). If "operation_id" is None in this case, then "wait_callback" will only be
invoked once all operations for this user are complete.
"""
def _OnCompletedOp(type=None, value=None, tb=None):
"""Wraps the caller's callback so that it is called in the original context, and any
exception is raised in the original context.
"""
if (type, value, tb) != (None, None, None):
raise type, value, tb
wait_callback()
@gen.engine
def _ExecuteAll():
"""Executes all ops within the scope of an OpContext. "yield" is not supported in the
static scope of OpContext, which is why this is a separate function.
"""
try:
self._is_executing = True
self._requery = True
while self._requery:
yield self._ExecuteAll(operation_id=operation_id)
finally:
# Notify any remaining listeners that their operations are complete (since all operations are now complete).
for cb_op_id in self._sync_cb_map.keys():
self._InvokeSyncCallbacks(cb_op_id)
# Complete execution.
self._is_executing = False
self._callback()
# Add callbacks for synchronous case.
if wait_callback is not None:
self._sync_cb_map[operation_id].append(stack_context.wrap(_OnCompletedOp))
if not self._is_executing:
# Establish op context, and then call another func, since it is not safe to use a yield in the static scope
# of the "with stack_context" statement.
with stack_context.StackContext(OpContext()):
_ExecuteAll()
else:
# Sets flag so that once all operations are executed, the list of operations is re-queried
# in order to find any newly added operations.
self._requery = True
