291 lines
10 KiB
Python
291 lines
10 KiB
Python
# -*- coding: utf-8 -*-
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# Copyright 2014-2016 OpenMarket Ltd
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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from six import iteritems
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from frozendict import frozendict
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from twisted.internet import defer
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from synapse.util.logcontext import make_deferred_yieldable, run_in_background
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class EventContext(object):
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"""
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Attributes:
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state_group (int|None): state group id, if the state has been stored
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as a state group. This is usually only None if e.g. the event is
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an outlier.
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rejected (bool|str): A rejection reason if the event was rejected, else
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False
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push_actions (list[(str, list[object])]): list of (user_id, actions)
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tuples
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prev_group (int): Previously persisted state group. ``None`` for an
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outlier.
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delta_ids (dict[(str, str), str]): Delta from ``prev_group``.
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(type, state_key) -> event_id. ``None`` for an outlier.
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prev_state_events (?): XXX: is this ever set to anything other than
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the empty list?
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_current_state_ids (dict[(str, str), str]|None):
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The current state map including the current event. None if outlier
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or we haven't fetched the state from DB yet.
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(type, state_key) -> event_id
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_prev_state_ids (dict[(str, str), str]|None):
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The current state map excluding the current event. None if outlier
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or we haven't fetched the state from DB yet.
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(type, state_key) -> event_id
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_fetching_state_deferred (Deferred|None): Resolves when *_state_ids have
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been calculated. None if we haven't started calculating yet
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_event_type (str): The type of the event the context is associated with.
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Only set when state has not been fetched yet.
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_event_state_key (str|None): The state_key of the event the context is
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associated with. Only set when state has not been fetched yet.
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_prev_state_id (str|None): If the event associated with the context is
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a state event, then `_prev_state_id` is the event_id of the state
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that was replaced.
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Only set when state has not been fetched yet.
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"""
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__slots__ = [
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"state_group",
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"rejected",
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"prev_group",
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"delta_ids",
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"prev_state_events",
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"app_service",
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"_current_state_ids",
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"_prev_state_ids",
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"_prev_state_id",
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"_event_type",
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"_event_state_key",
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"_fetching_state_deferred",
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]
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def __init__(self):
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self.prev_state_events = []
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self.rejected = False
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self.app_service = None
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@staticmethod
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def with_state(state_group, current_state_ids, prev_state_ids,
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prev_group=None, delta_ids=None):
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context = EventContext()
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# The current state including the current event
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context._current_state_ids = current_state_ids
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# The current state excluding the current event
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context._prev_state_ids = prev_state_ids
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context.state_group = state_group
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context._prev_state_id = None
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context._event_type = None
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context._event_state_key = None
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context._fetching_state_deferred = defer.succeed(None)
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# A previously persisted state group and a delta between that
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# and this state.
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context.prev_group = prev_group
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context.delta_ids = delta_ids
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return context
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@defer.inlineCallbacks
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def serialize(self, event, store):
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"""Converts self to a type that can be serialized as JSON, and then
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deserialized by `deserialize`
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Args:
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event (FrozenEvent): The event that this context relates to
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Returns:
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dict
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"""
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# We don't serialize the full state dicts, instead they get pulled out
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# of the DB on the other side. However, the other side can't figure out
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# the prev_state_ids, so if we're a state event we include the event
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# id that we replaced in the state.
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if event.is_state():
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prev_state_ids = yield self.get_prev_state_ids(store)
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prev_state_id = prev_state_ids.get((event.type, event.state_key))
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else:
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prev_state_id = None
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defer.returnValue({
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"prev_state_id": prev_state_id,
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"event_type": event.type,
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"event_state_key": event.state_key if event.is_state() else None,
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"state_group": self.state_group,
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"rejected": self.rejected,
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"prev_group": self.prev_group,
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"delta_ids": _encode_state_dict(self.delta_ids),
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"prev_state_events": self.prev_state_events,
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"app_service_id": self.app_service.id if self.app_service else None
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})
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@staticmethod
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def deserialize(store, input):
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"""Converts a dict that was produced by `serialize` back into a
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EventContext.
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Args:
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store (DataStore): Used to convert AS ID to AS object
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input (dict): A dict produced by `serialize`
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Returns:
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EventContext
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"""
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context = EventContext()
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# We use the state_group and prev_state_id stuff to pull the
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# current_state_ids out of the DB and construct prev_state_ids.
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context._prev_state_id = input["prev_state_id"]
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context._event_type = input["event_type"]
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context._event_state_key = input["event_state_key"]
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context._current_state_ids = None
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context._prev_state_ids = None
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context._fetching_state_deferred = None
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context.state_group = input["state_group"]
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context.prev_group = input["prev_group"]
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context.delta_ids = _decode_state_dict(input["delta_ids"])
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context.rejected = input["rejected"]
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context.prev_state_events = input["prev_state_events"]
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app_service_id = input["app_service_id"]
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if app_service_id:
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context.app_service = store.get_app_service_by_id(app_service_id)
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return context
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@defer.inlineCallbacks
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def get_current_state_ids(self, store):
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"""Gets the current state IDs
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Returns:
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Deferred[dict[(str, str), str]|None]: Returns None if state_group
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is None, which happens when the associated event is an outlier.
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"""
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if not self._fetching_state_deferred:
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self._fetching_state_deferred = run_in_background(
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self._fill_out_state, store,
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)
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yield make_deferred_yieldable(self._fetching_state_deferred)
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defer.returnValue(self._current_state_ids)
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@defer.inlineCallbacks
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def get_prev_state_ids(self, store):
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"""Gets the prev state IDs
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Returns:
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Deferred[dict[(str, str), str]|None]: Returns None if state_group
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is None, which happens when the associated event is an outlier.
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"""
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if not self._fetching_state_deferred:
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self._fetching_state_deferred = run_in_background(
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self._fill_out_state, store,
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)
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yield make_deferred_yieldable(self._fetching_state_deferred)
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defer.returnValue(self._prev_state_ids)
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def get_cached_current_state_ids(self):
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"""Gets the current state IDs if we have them already cached.
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Returns:
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dict[(str, str), str]|None: Returns None if we haven't cached the
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state or if state_group is None, which happens when the associated
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event is an outlier.
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"""
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return self._current_state_ids
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@defer.inlineCallbacks
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def _fill_out_state(self, store):
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"""Called to populate the _current_state_ids and _prev_state_ids
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attributes by loading from the database.
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"""
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if self.state_group is None:
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return
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self._current_state_ids = yield store.get_state_ids_for_group(
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self.state_group,
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)
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if self._prev_state_id and self._event_state_key is not None:
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self._prev_state_ids = dict(self._current_state_ids)
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key = (self._event_type, self._event_state_key)
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self._prev_state_ids[key] = self._prev_state_id
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else:
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self._prev_state_ids = self._current_state_ids
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@defer.inlineCallbacks
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def update_state(self, state_group, prev_state_ids, current_state_ids,
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prev_group, delta_ids):
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"""Replace the state in the context
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"""
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# We need to make sure we wait for any ongoing fetching of state
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# to complete so that the updated state doesn't get clobbered
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if self._fetching_state_deferred:
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yield make_deferred_yieldable(self._fetching_state_deferred)
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self.state_group = state_group
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self._prev_state_ids = prev_state_ids
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self.prev_group = prev_group
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self._current_state_ids = current_state_ids
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self.delta_ids = delta_ids
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# We need to ensure that that we've marked as having fetched the state
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self._fetching_state_deferred = defer.succeed(None)
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def _encode_state_dict(state_dict):
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"""Since dicts of (type, state_key) -> event_id cannot be serialized in
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JSON we need to convert them to a form that can.
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"""
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if state_dict is None:
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return None
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return [
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(etype, state_key, v)
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for (etype, state_key), v in iteritems(state_dict)
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]
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def _decode_state_dict(input):
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"""Decodes a state dict encoded using `_encode_state_dict` above
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"""
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if input is None:
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return None
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return frozendict({(etype, state_key,): v for etype, state_key, v in input})
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