mirror of
https://git.anonymousland.org/anonymousland/synapse.git
synced 2024-10-01 11:49:51 -04:00
662 lines
24 KiB
Python
662 lines
24 KiB
Python
# -*- coding: utf-8 -*-
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# Copyright 2014-2016 OpenMarket Ltd
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# Copyright 2018 New Vector 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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import logging
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from collections import namedtuple
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from six import iteritems, itervalues
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from frozendict import frozendict
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from twisted.internet import defer
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from synapse.api.constants import EventTypes, RoomVersions
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from synapse.events.snapshot import EventContext
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from synapse.state import v1
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from synapse.util.async import Linearizer
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from synapse.util.caches import CACHE_SIZE_FACTOR
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from synapse.util.caches.expiringcache import ExpiringCache
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from synapse.util.logutils import log_function
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from synapse.util.metrics import Measure
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logger = logging.getLogger(__name__)
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KeyStateTuple = namedtuple("KeyStateTuple", ("context", "type", "state_key"))
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SIZE_OF_CACHE = int(100000 * CACHE_SIZE_FACTOR)
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EVICTION_TIMEOUT_SECONDS = 60 * 60
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_NEXT_STATE_ID = 1
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POWER_KEY = (EventTypes.PowerLevels, "")
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def _gen_state_id():
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global _NEXT_STATE_ID
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s = "X%d" % (_NEXT_STATE_ID,)
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_NEXT_STATE_ID += 1
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return s
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class _StateCacheEntry(object):
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__slots__ = ["state", "state_group", "state_id", "prev_group", "delta_ids"]
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def __init__(self, state, state_group, prev_group=None, delta_ids=None):
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# dict[(str, str), str] map from (type, state_key) to event_id
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self.state = frozendict(state)
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# the ID of a state group if one and only one is involved.
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# otherwise, None otherwise?
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self.state_group = state_group
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self.prev_group = prev_group
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self.delta_ids = frozendict(delta_ids) if delta_ids is not None else None
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# The `state_id` is a unique ID we generate that can be used as ID for
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# this collection of state. Usually this would be the same as the
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# state group, but on worker instances we can't generate a new state
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# group each time we resolve state, so we generate a separate one that
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# isn't persisted and is used solely for caches.
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# `state_id` is either a state_group (and so an int) or a string. This
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# ensures we don't accidentally persist a state_id as a stateg_group
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if state_group:
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self.state_id = state_group
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else:
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self.state_id = _gen_state_id()
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def __len__(self):
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return len(self.state)
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class StateHandler(object):
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"""Fetches bits of state from the stores, and does state resolution
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where necessary
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"""
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def __init__(self, hs):
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self.clock = hs.get_clock()
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self.store = hs.get_datastore()
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self.hs = hs
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self._state_resolution_handler = hs.get_state_resolution_handler()
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def start_caching(self):
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# TODO: remove this shim
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self._state_resolution_handler.start_caching()
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@defer.inlineCallbacks
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def get_current_state(self, room_id, event_type=None, state_key="",
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latest_event_ids=None):
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""" Retrieves the current state for the room. This is done by
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calling `get_latest_events_in_room` to get the leading edges of the
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event graph and then resolving any of the state conflicts.
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This is equivalent to getting the state of an event that were to send
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next before receiving any new events.
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If `event_type` is specified, then the method returns only the one
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event (or None) with that `event_type` and `state_key`.
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Returns:
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map from (type, state_key) to event
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"""
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if not latest_event_ids:
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latest_event_ids = yield self.store.get_latest_event_ids_in_room(room_id)
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logger.debug("calling resolve_state_groups from get_current_state")
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ret = yield self.resolve_state_groups_for_events(room_id, latest_event_ids)
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state = ret.state
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if event_type:
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event_id = state.get((event_type, state_key))
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event = None
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if event_id:
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event = yield self.store.get_event(event_id, allow_none=True)
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defer.returnValue(event)
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return
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state_map = yield self.store.get_events(list(state.values()),
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get_prev_content=False)
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state = {
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key: state_map[e_id] for key, e_id in iteritems(state) if e_id in state_map
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}
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defer.returnValue(state)
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@defer.inlineCallbacks
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def get_current_state_ids(self, room_id, latest_event_ids=None):
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"""Get the current state, or the state at a set of events, for a room
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Args:
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room_id (str):
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latest_event_ids (iterable[str]|None): if given, the forward
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extremities to resolve. If None, we look them up from the
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database (via a cache)
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Returns:
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Deferred[dict[(str, str), str)]]: the state dict, mapping from
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(event_type, state_key) -> event_id
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"""
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if not latest_event_ids:
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latest_event_ids = yield self.store.get_latest_event_ids_in_room(room_id)
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logger.debug("calling resolve_state_groups from get_current_state_ids")
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ret = yield self.resolve_state_groups_for_events(room_id, latest_event_ids)
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state = ret.state
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defer.returnValue(state)
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@defer.inlineCallbacks
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def get_current_user_in_room(self, room_id, latest_event_ids=None):
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if not latest_event_ids:
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latest_event_ids = yield self.store.get_latest_event_ids_in_room(room_id)
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logger.debug("calling resolve_state_groups from get_current_user_in_room")
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entry = yield self.resolve_state_groups_for_events(room_id, latest_event_ids)
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joined_users = yield self.store.get_joined_users_from_state(room_id, entry)
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defer.returnValue(joined_users)
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@defer.inlineCallbacks
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def get_current_hosts_in_room(self, room_id, latest_event_ids=None):
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if not latest_event_ids:
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latest_event_ids = yield self.store.get_latest_event_ids_in_room(room_id)
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logger.debug("calling resolve_state_groups from get_current_hosts_in_room")
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entry = yield self.resolve_state_groups_for_events(room_id, latest_event_ids)
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joined_hosts = yield self.store.get_joined_hosts(room_id, entry)
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defer.returnValue(joined_hosts)
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@defer.inlineCallbacks
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def compute_event_context(self, event, old_state=None):
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"""Build an EventContext structure for the event.
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This works out what the current state should be for the event, and
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generates a new state group if necessary.
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Args:
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event (synapse.events.EventBase):
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old_state (dict|None): The state at the event if it can't be
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calculated from existing events. This is normally only specified
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when receiving an event from federation where we don't have the
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prev events for, e.g. when backfilling.
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Returns:
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synapse.events.snapshot.EventContext:
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"""
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if event.internal_metadata.is_outlier():
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# If this is an outlier, then we know it shouldn't have any current
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# state. Certainly store.get_current_state won't return any, and
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# persisting the event won't store the state group.
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if old_state:
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prev_state_ids = {
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(s.type, s.state_key): s.event_id for s in old_state
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}
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if event.is_state():
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current_state_ids = dict(prev_state_ids)
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key = (event.type, event.state_key)
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current_state_ids[key] = event.event_id
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else:
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current_state_ids = prev_state_ids
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else:
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current_state_ids = {}
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prev_state_ids = {}
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# We don't store state for outliers, so we don't generate a state
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# group for it.
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context = EventContext.with_state(
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state_group=None,
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current_state_ids=current_state_ids,
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prev_state_ids=prev_state_ids,
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)
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defer.returnValue(context)
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if old_state:
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# We already have the state, so we don't need to calculate it.
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# Let's just correctly fill out the context and create a
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# new state group for it.
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prev_state_ids = {
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(s.type, s.state_key): s.event_id for s in old_state
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}
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if event.is_state():
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key = (event.type, event.state_key)
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if key in prev_state_ids:
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replaces = prev_state_ids[key]
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if replaces != event.event_id: # Paranoia check
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event.unsigned["replaces_state"] = replaces
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current_state_ids = dict(prev_state_ids)
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current_state_ids[key] = event.event_id
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else:
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current_state_ids = prev_state_ids
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state_group = yield self.store.store_state_group(
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event.event_id,
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event.room_id,
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prev_group=None,
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delta_ids=None,
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current_state_ids=current_state_ids,
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)
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context = EventContext.with_state(
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state_group=state_group,
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current_state_ids=current_state_ids,
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prev_state_ids=prev_state_ids,
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)
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defer.returnValue(context)
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logger.debug("calling resolve_state_groups from compute_event_context")
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if event.type == EventTypes.Create:
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room_version = event.content.get("room_version", RoomVersions.V1)
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else:
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room_version = None
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entry = yield self.resolve_state_groups_for_events(
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event.room_id, [e for e, _ in event.prev_events],
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explicit_room_version=room_version,
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)
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prev_state_ids = entry.state
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prev_group = None
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delta_ids = None
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if event.is_state():
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# If this is a state event then we need to create a new state
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# group for the state after this event.
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key = (event.type, event.state_key)
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if key in prev_state_ids:
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replaces = prev_state_ids[key]
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event.unsigned["replaces_state"] = replaces
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current_state_ids = dict(prev_state_ids)
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current_state_ids[key] = event.event_id
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if entry.state_group:
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# If the state at the event has a state group assigned then
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# we can use that as the prev group
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prev_group = entry.state_group
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delta_ids = {
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key: event.event_id
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}
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elif entry.prev_group:
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# If the state at the event only has a prev group, then we can
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# use that as a prev group too.
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prev_group = entry.prev_group
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delta_ids = dict(entry.delta_ids)
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delta_ids[key] = event.event_id
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state_group = yield self.store.store_state_group(
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event.event_id,
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event.room_id,
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prev_group=prev_group,
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delta_ids=delta_ids,
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current_state_ids=current_state_ids,
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)
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else:
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current_state_ids = prev_state_ids
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prev_group = entry.prev_group
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delta_ids = entry.delta_ids
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if entry.state_group is None:
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entry.state_group = yield self.store.store_state_group(
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event.event_id,
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event.room_id,
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prev_group=entry.prev_group,
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delta_ids=entry.delta_ids,
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current_state_ids=current_state_ids,
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)
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entry.state_id = entry.state_group
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state_group = entry.state_group
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context = EventContext.with_state(
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state_group=state_group,
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current_state_ids=current_state_ids,
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prev_state_ids=prev_state_ids,
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prev_group=prev_group,
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delta_ids=delta_ids,
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)
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defer.returnValue(context)
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@defer.inlineCallbacks
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def resolve_state_groups_for_events(self, room_id, event_ids,
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explicit_room_version=None):
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""" Given a list of event_ids this method fetches the state at each
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event, resolves conflicts between them and returns them.
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Args:
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room_id (str)
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event_ids (list[str])
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explicit_room_version (str|None): If set uses the the given room
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version to choose the resolution algorithm. If None, then
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checks the database for room version.
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Returns:
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Deferred[_StateCacheEntry]: resolved state
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"""
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logger.debug("resolve_state_groups event_ids %s", event_ids)
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# map from state group id to the state in that state group (where
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# 'state' is a map from state key to event id)
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# dict[int, dict[(str, str), str]]
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state_groups_ids = yield self.store.get_state_groups_ids(
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room_id, event_ids
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)
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if len(state_groups_ids) == 0:
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defer.returnValue(_StateCacheEntry(
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state={},
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state_group=None,
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))
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elif len(state_groups_ids) == 1:
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name, state_list = list(state_groups_ids.items()).pop()
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prev_group, delta_ids = yield self.store.get_state_group_delta(name)
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defer.returnValue(_StateCacheEntry(
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state=state_list,
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state_group=name,
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prev_group=prev_group,
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delta_ids=delta_ids,
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))
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room_version = explicit_room_version
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if not room_version:
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room_version = yield self.store.get_room_version(room_id)
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result = yield self._state_resolution_handler.resolve_state_groups(
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room_id, room_version, state_groups_ids, None,
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self._state_map_factory,
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)
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defer.returnValue(result)
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def _state_map_factory(self, ev_ids):
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return self.store.get_events(
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ev_ids, get_prev_content=False, check_redacted=False,
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)
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@defer.inlineCallbacks
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def resolve_events(self, room_version, state_sets, event):
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logger.info(
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"Resolving state for %s with %d groups", event.room_id, len(state_sets)
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)
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state_set_ids = [{
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(ev.type, ev.state_key): ev.event_id
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for ev in st
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} for st in state_sets]
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state_map = {
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ev.event_id: ev
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for st in state_sets
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for ev in st
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}
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room_version = yield self.store.get_room_version(event.room_id)
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with Measure(self.clock, "state._resolve_events"):
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new_state = resolve_events_with_state_map(
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room_version, state_set_ids, state_map,
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)
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new_state = {
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key: state_map[ev_id] for key, ev_id in iteritems(new_state)
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}
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defer.returnValue(new_state)
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class StateResolutionHandler(object):
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"""Responsible for doing state conflict resolution.
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Note that the storage layer depends on this handler, so all functions must
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be storage-independent.
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"""
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def __init__(self, hs):
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self.clock = hs.get_clock()
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# dict of set of event_ids -> _StateCacheEntry.
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self._state_cache = None
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self.resolve_linearizer = Linearizer(name="state_resolve_lock")
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def start_caching(self):
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logger.debug("start_caching")
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self._state_cache = ExpiringCache(
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cache_name="state_cache",
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clock=self.clock,
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max_len=SIZE_OF_CACHE,
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expiry_ms=EVICTION_TIMEOUT_SECONDS * 1000,
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iterable=True,
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reset_expiry_on_get=True,
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)
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self._state_cache.start()
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@defer.inlineCallbacks
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@log_function
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def resolve_state_groups(
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self, room_id, room_version, state_groups_ids, event_map, state_map_factory,
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):
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"""Resolves conflicts between a set of state groups
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Always generates a new state group (unless we hit the cache), so should
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not be called for a single state group
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Args:
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room_id (str): room we are resolving for (used for logging)
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room_version (str): version of the room
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state_groups_ids (dict[int, dict[(str, str), str]]):
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map from state group id to the state in that state group
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(where 'state' is a map from state key to event id)
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event_map(dict[str,FrozenEvent]|None):
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a dict from event_id to event, for any events that we happen to
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have in flight (eg, those currently being persisted). This will be
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used as a starting point fof finding the state we need; any missing
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events will be requested via state_map_factory.
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If None, all events will be fetched via state_map_factory.
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Returns:
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Deferred[_StateCacheEntry]: resolved state
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"""
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logger.debug(
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"resolve_state_groups state_groups %s",
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state_groups_ids.keys()
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)
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group_names = frozenset(state_groups_ids.keys())
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with (yield self.resolve_linearizer.queue(group_names)):
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if self._state_cache is not None:
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cache = self._state_cache.get(group_names, None)
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if cache:
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defer.returnValue(cache)
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logger.info(
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"Resolving state for %s with %d groups", room_id, len(state_groups_ids)
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)
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# start by assuming we won't have any conflicted state, and build up the new
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# state map by iterating through the state groups. If we discover a conflict,
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# we give up and instead use `resolve_events_with_factory`.
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#
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# XXX: is this actually worthwhile, or should we just let
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# resolve_events_with_factory do it?
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new_state = {}
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conflicted_state = False
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for st in itervalues(state_groups_ids):
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for key, e_id in iteritems(st):
|
|
if key in new_state:
|
|
conflicted_state = True
|
|
break
|
|
new_state[key] = e_id
|
|
if conflicted_state:
|
|
break
|
|
|
|
if conflicted_state:
|
|
logger.info("Resolving conflicted state for %r", room_id)
|
|
with Measure(self.clock, "state._resolve_events"):
|
|
new_state = yield resolve_events_with_factory(
|
|
room_version,
|
|
list(itervalues(state_groups_ids)),
|
|
event_map=event_map,
|
|
state_map_factory=state_map_factory,
|
|
)
|
|
|
|
# if the new state matches any of the input state groups, we can
|
|
# use that state group again. Otherwise we will generate a state_id
|
|
# which will be used as a cache key for future resolutions, but
|
|
# not get persisted.
|
|
|
|
with Measure(self.clock, "state.create_group_ids"):
|
|
cache = _make_state_cache_entry(new_state, state_groups_ids)
|
|
|
|
if self._state_cache is not None:
|
|
self._state_cache[group_names] = cache
|
|
|
|
defer.returnValue(cache)
|
|
|
|
|
|
def _make_state_cache_entry(
|
|
new_state,
|
|
state_groups_ids,
|
|
):
|
|
"""Given a resolved state, and a set of input state groups, pick one to base
|
|
a new state group on (if any), and return an appropriately-constructed
|
|
_StateCacheEntry.
|
|
|
|
Args:
|
|
new_state (dict[(str, str), str]): resolved state map (mapping from
|
|
(type, state_key) to event_id)
|
|
|
|
state_groups_ids (dict[int, dict[(str, str), str]]):
|
|
map from state group id to the state in that state group
|
|
(where 'state' is a map from state key to event id)
|
|
|
|
Returns:
|
|
_StateCacheEntry
|
|
"""
|
|
# if the new state matches any of the input state groups, we can
|
|
# use that state group again. Otherwise we will generate a state_id
|
|
# which will be used as a cache key for future resolutions, but
|
|
# not get persisted.
|
|
|
|
# first look for exact matches
|
|
new_state_event_ids = set(itervalues(new_state))
|
|
for sg, state in iteritems(state_groups_ids):
|
|
if len(new_state_event_ids) != len(state):
|
|
continue
|
|
|
|
old_state_event_ids = set(itervalues(state))
|
|
if new_state_event_ids == old_state_event_ids:
|
|
# got an exact match.
|
|
return _StateCacheEntry(
|
|
state=new_state,
|
|
state_group=sg,
|
|
)
|
|
|
|
# TODO: We want to create a state group for this set of events, to
|
|
# increase cache hits, but we need to make sure that it doesn't
|
|
# end up as a prev_group without being added to the database
|
|
|
|
# failing that, look for the closest match.
|
|
prev_group = None
|
|
delta_ids = None
|
|
|
|
for old_group, old_state in iteritems(state_groups_ids):
|
|
n_delta_ids = {
|
|
k: v
|
|
for k, v in iteritems(new_state)
|
|
if old_state.get(k) != v
|
|
}
|
|
if not delta_ids or len(n_delta_ids) < len(delta_ids):
|
|
prev_group = old_group
|
|
delta_ids = n_delta_ids
|
|
|
|
return _StateCacheEntry(
|
|
state=new_state,
|
|
state_group=None,
|
|
prev_group=prev_group,
|
|
delta_ids=delta_ids,
|
|
)
|
|
|
|
|
|
def resolve_events_with_state_map(room_version, state_sets, state_map):
|
|
"""
|
|
Args:
|
|
room_version(str): Version of the room
|
|
state_sets(list): List of dicts of (type, state_key) -> event_id,
|
|
which are the different state groups to resolve.
|
|
state_map(dict): a dict from event_id to event, for all events in
|
|
state_sets.
|
|
|
|
Returns
|
|
dict[(str, str), str]:
|
|
a map from (type, state_key) to event_id.
|
|
"""
|
|
if room_version in (RoomVersions.V1, RoomVersions.VDH_TEST,):
|
|
return v1.resolve_events_with_state_map(
|
|
state_sets, state_map,
|
|
)
|
|
else:
|
|
# This should only happen if we added a version but forgot to add it to
|
|
# the list above.
|
|
raise Exception(
|
|
"No state resolution algorithm defined for version %r" % (room_version,)
|
|
)
|
|
|
|
|
|
def resolve_events_with_factory(room_version, state_sets, event_map, state_map_factory):
|
|
"""
|
|
Args:
|
|
room_version(str): Version of the room
|
|
|
|
state_sets(list): List of dicts of (type, state_key) -> event_id,
|
|
which are the different state groups to resolve.
|
|
|
|
event_map(dict[str,FrozenEvent]|None):
|
|
a dict from event_id to event, for any events that we happen to
|
|
have in flight (eg, those currently being persisted). This will be
|
|
used as a starting point fof finding the state we need; any missing
|
|
events will be requested via state_map_factory.
|
|
|
|
If None, all events will be fetched via state_map_factory.
|
|
|
|
state_map_factory(func): will be called
|
|
with a list of event_ids that are needed, and should return with
|
|
a Deferred of dict of event_id to event.
|
|
|
|
Returns
|
|
Deferred[dict[(str, str), str]]:
|
|
a map from (type, state_key) to event_id.
|
|
"""
|
|
if room_version in (RoomVersions.V1, RoomVersions.VDH_TEST,):
|
|
return v1.resolve_events_with_factory(
|
|
state_sets, event_map, state_map_factory,
|
|
)
|
|
else:
|
|
# This should only happen if we added a version but forgot to add it to
|
|
# the list above.
|
|
raise Exception(
|
|
"No state resolution algorithm defined for version %r" % (room_version,)
|
|
)
|