|
- # Copyright 2018 New Vector 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.
-
- import hashlib
- import logging
- from typing import (
- Awaitable,
- Callable,
- Dict,
- Iterable,
- List,
- Optional,
- Sequence,
- Set,
- Tuple,
- )
-
- from synapse import event_auth
- from synapse.api.constants import EventTypes
- from synapse.api.errors import AuthError
- from synapse.api.room_versions import RoomVersion
- from synapse.events import EventBase
- from synapse.types import MutableStateMap, StateMap, StrCollection
-
- logger = logging.getLogger(__name__)
-
-
- POWER_KEY = (EventTypes.PowerLevels, "")
-
-
- async def resolve_events_with_store(
- room_id: str,
- room_version: RoomVersion,
- state_sets: Sequence[StateMap[str]],
- event_map: Optional[Dict[str, EventBase]],
- state_map_factory: Callable[[StrCollection], Awaitable[Dict[str, EventBase]]],
- ) -> StateMap[str]:
- """
- Args:
- room_id: the room we are working in
-
- state_sets: List of dicts of (type, state_key) -> event_id,
- which are the different state groups to resolve.
-
- event_map:
- 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 for 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: will be called
- with a list of event_ids that are needed, and should return with
- an Awaitable that resolves to a dict of event_id to event.
-
- Returns:
- A map from (type, state_key) to event_id.
- """
- if len(state_sets) == 1:
- return state_sets[0]
-
- unconflicted_state, conflicted_state = _seperate(state_sets)
-
- needed_events = {
- event_id for event_ids in conflicted_state.values() for event_id in event_ids
- }
- needed_event_count = len(needed_events)
- if event_map is not None:
- needed_events -= set(event_map.keys())
-
- logger.info(
- "Asking for %d/%d conflicted events", len(needed_events), needed_event_count
- )
-
- # A map from state event id to event. Only includes the state events which
- # are in conflict (and those in event_map).
- state_map = await state_map_factory(needed_events)
- if event_map is not None:
- state_map.update(event_map)
-
- # everything in the state map should be in the right room
- for event in state_map.values():
- if event.room_id != room_id:
- raise Exception(
- "Attempting to state-resolve for room %s with event %s which is in %s"
- % (
- room_id,
- event.event_id,
- event.room_id,
- )
- )
-
- # get the ids of the auth events which allow us to authenticate the
- # conflicted state, picking only from the unconflicting state.
- auth_events = _create_auth_events_from_maps(
- room_version, unconflicted_state, conflicted_state, state_map
- )
-
- new_needed_events = set(auth_events.values())
- new_needed_event_count = len(new_needed_events)
- new_needed_events -= needed_events
- if event_map is not None:
- new_needed_events -= set(event_map.keys())
-
- logger.info(
- "Asking for %d/%d auth events", len(new_needed_events), new_needed_event_count
- )
-
- state_map_new = await state_map_factory(new_needed_events)
- for event in state_map_new.values():
- if event.room_id != room_id:
- raise Exception(
- "Attempting to state-resolve for room %s with event %s which is in %s"
- % (
- room_id,
- event.event_id,
- event.room_id,
- )
- )
-
- state_map.update(state_map_new)
-
- return _resolve_with_state(
- room_version, unconflicted_state, conflicted_state, auth_events, state_map
- )
-
-
- def _seperate(
- state_sets: Iterable[StateMap[str]],
- ) -> Tuple[MutableStateMap[str], MutableStateMap[Set[str]]]:
- """Takes the state_sets and figures out which keys are conflicted and
- which aren't. i.e., which have multiple different event_ids associated
- with them in different state sets.
-
- Args:
- state_sets:
- List of dicts of (type, state_key) -> event_id, which are the
- different state groups to resolve.
-
- Returns:
- A tuple of (unconflicted_state, conflicted_state), where:
-
- unconflicted_state is a dict mapping (type, state_key)->event_id
- for unconflicted state keys.
-
- conflicted_state is a dict mapping (type, state_key) to a set of
- event ids for conflicted state keys.
- """
- state_set_iterator = iter(state_sets)
- unconflicted_state = dict(next(state_set_iterator))
- conflicted_state: MutableStateMap[Set[str]] = {}
-
- for state_set in state_set_iterator:
- for key, value in state_set.items():
- # Check if there is an unconflicted entry for the state key.
- unconflicted_value = unconflicted_state.get(key)
- if unconflicted_value is None:
- # There isn't an unconflicted entry so check if there is a
- # conflicted entry.
- ls = conflicted_state.get(key)
- if ls is None:
- # There wasn't a conflicted entry so haven't seen this key before.
- # Therefore it isn't conflicted yet.
- unconflicted_state[key] = value
- else:
- # This key is already conflicted, add our value to the conflict set.
- ls.add(value)
- elif unconflicted_value != value:
- # If the unconflicted value is not the same as our value then we
- # have a new conflict. So move the key from the unconflicted_state
- # to the conflicted state.
- conflicted_state[key] = {value, unconflicted_value}
- unconflicted_state.pop(key, None)
-
- return unconflicted_state, conflicted_state
-
-
- def _create_auth_events_from_maps(
- room_version: RoomVersion,
- unconflicted_state: StateMap[str],
- conflicted_state: StateMap[Set[str]],
- state_map: Dict[str, EventBase],
- ) -> StateMap[str]:
- """
-
- Args:
- room_version: The room version.
- unconflicted_state: The unconflicted state map.
- conflicted_state: The conflicted state map.
- state_map:
-
- Returns:
- A map from state key to event id.
- """
- auth_events = {}
- for event_ids in conflicted_state.values():
- for event_id in event_ids:
- if event_id in state_map:
- keys = event_auth.auth_types_for_event(
- room_version, state_map[event_id]
- )
- for key in keys:
- if key not in auth_events:
- auth_event_id = unconflicted_state.get(key, None)
- if auth_event_id:
- auth_events[key] = auth_event_id
- return auth_events
-
-
- def _resolve_with_state(
- room_version: RoomVersion,
- unconflicted_state_ids: MutableStateMap[str],
- conflicted_state_ids: StateMap[Set[str]],
- auth_event_ids: StateMap[str],
- state_map: Dict[str, EventBase],
- ) -> MutableStateMap[str]:
- conflicted_state = {}
- for key, event_ids in conflicted_state_ids.items():
- events = [state_map[ev_id] for ev_id in event_ids if ev_id in state_map]
- if len(events) > 1:
- conflicted_state[key] = events
- elif len(events) == 1:
- unconflicted_state_ids[key] = events[0].event_id
-
- auth_events = {
- key: state_map[ev_id]
- for key, ev_id in auth_event_ids.items()
- if ev_id in state_map
- }
-
- try:
- resolved_state = _resolve_state_events(
- room_version, conflicted_state, auth_events
- )
- except Exception:
- logger.exception("Failed to resolve state")
- raise
-
- new_state = unconflicted_state_ids
- for key, event in resolved_state.items():
- new_state[key] = event.event_id
-
- return new_state
-
-
- def _resolve_state_events(
- room_version: RoomVersion,
- conflicted_state: StateMap[List[EventBase]],
- auth_events: MutableStateMap[EventBase],
- ) -> StateMap[EventBase]:
- """This is where we actually decide which of the conflicted state to
- use.
-
- We resolve conflicts in the following order:
- 1. power levels
- 2. join rules
- 3. memberships
- 4. other events.
- """
- resolved_state = {}
- if POWER_KEY in conflicted_state:
- events = conflicted_state[POWER_KEY]
- logger.debug("Resolving conflicted power levels %r", events)
- resolved_state[POWER_KEY] = _resolve_auth_events(
- room_version, events, auth_events
- )
-
- auth_events.update(resolved_state)
-
- for key, events in conflicted_state.items():
- if key[0] == EventTypes.JoinRules:
- logger.debug("Resolving conflicted join rules %r", events)
- resolved_state[key] = _resolve_auth_events(
- room_version, events, auth_events
- )
-
- auth_events.update(resolved_state)
-
- for key, events in conflicted_state.items():
- if key[0] == EventTypes.Member:
- logger.debug("Resolving conflicted member lists %r", events)
- resolved_state[key] = _resolve_auth_events(
- room_version, events, auth_events
- )
-
- auth_events.update(resolved_state)
-
- for key, events in conflicted_state.items():
- if key not in resolved_state:
- logger.debug("Resolving conflicted state %r:%r", key, events)
- resolved_state[key] = _resolve_normal_events(events, auth_events)
-
- return resolved_state
-
-
- def _resolve_auth_events(
- room_version: RoomVersion, events: List[EventBase], auth_events: StateMap[EventBase]
- ) -> EventBase:
- reverse = list(reversed(_ordered_events(events)))
-
- auth_keys = {
- key
- for event in events
- for key in event_auth.auth_types_for_event(room_version, event)
- }
-
- new_auth_events = {}
- for key in auth_keys:
- auth_event = auth_events.get(key, None)
- if auth_event:
- new_auth_events[key] = auth_event
-
- auth_events = new_auth_events
-
- prev_event = reverse[0]
- for event in reverse[1:]:
- auth_events[(prev_event.type, prev_event.state_key)] = prev_event
- try:
- # The signatures have already been checked at this point
- event_auth.check_state_dependent_auth_rules(
- event,
- auth_events.values(),
- )
- prev_event = event
- except AuthError:
- return prev_event
-
- return event
-
-
- def _resolve_normal_events(
- events: List[EventBase], auth_events: StateMap[EventBase]
- ) -> EventBase:
- for event in _ordered_events(events):
- try:
- # The signatures have already been checked at this point
- event_auth.check_state_dependent_auth_rules(
- event,
- auth_events.values(),
- )
- return event
- except AuthError:
- pass
-
- # Use the last event (the one with the least depth) if they all fail
- # the auth check.
- return event
-
-
- def _ordered_events(events: Iterable[EventBase]) -> List[EventBase]:
- def key_func(e: EventBase) -> Tuple[int, str]:
- # we have to use utf-8 rather than ascii here because it turns out we allow
- # people to send us events with non-ascii event IDs :/
- return -int(e.depth), hashlib.sha1(e.event_id.encode("utf-8")).hexdigest()
-
- return sorted(events, key=key_func)
|