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# Copyright (C) 2015 by the Free Software Foundation, Inc.
#
# This file is part of GNU Mailman.
#
# GNU Mailman is free software: you can redistribute it and/or modify it under
# the terms of the GNU General Public License as published by the Free
# Software Foundation, either version 3 of the License, or (at your option)
# any later version.
#
# GNU Mailman is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
# FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
# more details.
#
# You should have received a copy of the GNU General Public License along with
# GNU Mailman. If not, see <http://www.gnu.org/licenses/>.
"""Generic workflow."""
__all__ = [
'Workflow',
]
import json
from collections import deque
from mailman.interfaces.workflow import IWorkflowStateManager
from zope.component import getUtility
class Workflow:
"""Generic workflow."""
_save_key = ''
_save_attributes = []
_initial_state = []
def __init__(self):
self._next = deque(self._initial_state)
def __iter__(self):
return self
def _pop(self):
name = self._next.popleft()
step = getattr(self, '_step_{}'.format(name))
return step, name
def __next__(self):
try:
step, name = self._pop()
step()
except IndexError:
raise StopIteration
except:
raise
def save_state(self):
state_manager = getUtility(IWorkflowStateManager)
data = {attr: getattr(self, attr) for attr in self._save_attributes}
# Note: only the next step is saved, not the whole stack. Not an issue
# since there's never more than a single step in the queue anyway.
# If we want to support more than a single step in the queue AND want
# to support state saving/restoring, change this method and the
# restore_state() method.
if len(self._next) == 0:
step = None
elif len(self._next) == 1:
step = self._next[0]
else:
raise AssertionError(
"Can't save a workflow state with more than one step "
"in the queue")
state_manager.save(
self.__class__.__name__,
self._save_key,
step,
json.dumps(data))
def restore_state(self):
state_manager = getUtility(IWorkflowStateManager)
state = state_manager.restore(self.__class__.__name__, self._save_key)
if state is not None:
self._next.clear()
if state.step:
self._next.append(state.step)
if state.data is not None:
for attr, value in json.loads(state.data).items():
setattr(self, attr, value)
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