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- # -*- coding: utf-8 -*-
- # Copyright 2014-2016 OpenMarket Ltd
- #
- # Licensed under the Apache License, Version 2.0 (the "License");
- # you may not use this file except in compliance with the License.
- # You may obtain a copy of the License at
- #
- # http://www.apache.org/licenses/LICENSE-2.0
- #
- # Unless required by applicable law or agreed to in writing, software
- # distributed under the License is distributed on an "AS IS" BASIS,
- # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- # See the License for the specific language governing permissions and
- # limitations under the License.
- from frozendict import frozendict
- from twisted.internet import defer
- class EventContext(object):
- """
- Attributes:
- current_state_ids (dict[(str, str), str]):
- The current state map including the current event.
- (type, state_key) -> event_id
- prev_state_ids (dict[(str, str), str]):
- The current state map excluding the current event.
- (type, state_key) -> event_id
- state_group (int|None): state group id, if the state has been stored
- as a state group. This is usually only None if e.g. the event is
- an outlier.
- rejected (bool|str): A rejection reason if the event was rejected, else
- False
- push_actions (list[(str, list[object])]): list of (user_id, actions)
- tuples
- prev_group (int): Previously persisted state group. ``None`` for an
- outlier.
- delta_ids (dict[(str, str), str]): Delta from ``prev_group``.
- (type, state_key) -> event_id. ``None`` for an outlier.
- prev_state_events (?): XXX: is this ever set to anything other than
- the empty list?
- """
- __slots__ = [
- "current_state_ids",
- "prev_state_ids",
- "state_group",
- "rejected",
- "prev_group",
- "delta_ids",
- "prev_state_events",
- "app_service",
- ]
- def __init__(self):
- # The current state including the current event
- self.current_state_ids = None
- # The current state excluding the current event
- self.prev_state_ids = None
- self.state_group = None
- self.rejected = False
- # A previously persisted state group and a delta between that
- # and this state.
- self.prev_group = None
- self.delta_ids = None
- self.prev_state_events = None
- self.app_service = None
- def serialize(self, event):
- """Converts self to a type that can be serialized as JSON, and then
- deserialized by `deserialize`
- Args:
- event (FrozenEvent): The event that this context relates to
- Returns:
- dict
- """
- # We don't serialize the full state dicts, instead they get pulled out
- # of the DB on the other side. However, the other side can't figure out
- # the prev_state_ids, so if we're a state event we include the event
- # id that we replaced in the state.
- if event.is_state():
- prev_state_id = self.prev_state_ids.get((event.type, event.state_key))
- else:
- prev_state_id = None
- return {
- "prev_state_id": prev_state_id,
- "event_type": event.type,
- "event_state_key": event.state_key if event.is_state() else None,
- "state_group": self.state_group,
- "rejected": self.rejected,
- "prev_group": self.prev_group,
- "delta_ids": _encode_state_dict(self.delta_ids),
- "prev_state_events": self.prev_state_events,
- "app_service_id": self.app_service.id if self.app_service else None
- }
- @staticmethod
- @defer.inlineCallbacks
- def deserialize(store, input):
- """Converts a dict that was produced by `serialize` back into a
- EventContext.
- Args:
- store (DataStore): Used to convert AS ID to AS object
- input (dict): A dict produced by `serialize`
- Returns:
- EventContext
- """
- context = EventContext()
- context.state_group = input["state_group"]
- context.rejected = input["rejected"]
- context.prev_group = input["prev_group"]
- context.delta_ids = _decode_state_dict(input["delta_ids"])
- context.prev_state_events = input["prev_state_events"]
- # We use the state_group and prev_state_id stuff to pull the
- # current_state_ids out of the DB and construct prev_state_ids.
- prev_state_id = input["prev_state_id"]
- event_type = input["event_type"]
- event_state_key = input["event_state_key"]
- context.current_state_ids = yield store.get_state_ids_for_group(
- context.state_group,
- )
- if prev_state_id and event_state_key:
- context.prev_state_ids = dict(context.current_state_ids)
- context.prev_state_ids[(event_type, event_state_key)] = prev_state_id
- else:
- context.prev_state_ids = context.current_state_ids
- app_service_id = input["app_service_id"]
- if app_service_id:
- context.app_service = store.get_app_service_by_id(app_service_id)
- defer.returnValue(context)
- def _encode_state_dict(state_dict):
- """Since dicts of (type, state_key) -> event_id cannot be serialized in
- JSON we need to convert them to a form that can.
- """
- if state_dict is None:
- return None
- return [
- (etype, state_key, v)
- for (etype, state_key), v in state_dict.iteritems()
- ]
- def _decode_state_dict(input):
- """Decodes a state dict encoded using `_encode_state_dict` above
- """
- if input is None:
- return None
- return frozendict({(etype, state_key,): v for etype, state_key, v in input})
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