diff options
Diffstat (limited to 'synapse')
| -rw-r--r-- | synapse/state/v2.py | 87 |
1 files changed, 83 insertions, 4 deletions
diff --git a/synapse/state/v2.py b/synapse/state/v2.py index f57df0d728..ffc504ce77 100644 --- a/synapse/state/v2.py +++ b/synapse/state/v2.py @@ -38,7 +38,7 @@ from synapse.api.constants import EventTypes from synapse.api.errors import AuthError from synapse.api.room_versions import KNOWN_ROOM_VERSIONS from synapse.events import EventBase -from synapse.types import MutableStateMap, StateMap +from synapse.types import Collection, MutableStateMap, StateMap from synapse.util import Clock logger = logging.getLogger(__name__) @@ -252,9 +252,88 @@ async def _get_auth_chain_difference( Set of event IDs """ - difference = await state_res_store.get_auth_chain_difference( - [set(state_set.values()) for state_set in state_sets] - ) + # The `StateResolutionStore.get_auth_chain_difference` function assumes that + # all events passed to it (and their auth chains) have been persisted + # previously. This is not the case for any events in the `event_map`, and so + # we need to manually handle those events. + # + # We do this by: + # 1. calculating the auth chain difference for the state sets based on the + # events in `event_map` alone + # 2. replacing any events in the state_sets that are also in `event_map` + # with their auth events (recursively), and then calling + # `store.get_auth_chain_difference` as normal + # 3. adding the results of 1 and 2 together. + + # Map from event ID in `event_map` to their auth event IDs, and their auth + # event IDs if they appear in the `event_map`. This is the intersection of + # the event's auth chain with the events in the `event_map` *plus* their + # auth event IDs. + events_to_auth_chain = {} # type: Dict[str, Set[str]] + for event in event_map.values(): + chain = {event.event_id} + events_to_auth_chain[event.event_id] = chain + + to_search = [event] + while to_search: + for auth_id in to_search.pop().auth_event_ids(): + chain.add(auth_id) + auth_event = event_map.get(auth_id) + if auth_event: + to_search.append(auth_event) + + # We now a) calculate the auth chain difference for the unpersisted events + # and b) work out the state sets to pass to the store. + # + # Note: If the `event_map` is empty (which is the common case), we can do a + # much simpler calculation. + if event_map: + # The list of state sets to pass to the store, where each state set is a set + # of the event ids making up the state. This is similar to `state_sets`, + # except that (a) we only have event ids, not the complete + # ((type, state_key)->event_id) mappings; and (b) we have stripped out + # unpersisted events and replaced them with the persisted events in + # their auth chain. + state_sets_ids = [] # type: List[Set[str]] + + # For each state set, the unpersisted event IDs reachable (by their auth + # chain) from the events in that set. + unpersisted_set_ids = [] # type: List[Set[str]] + + for state_set in state_sets: + set_ids = set() # type: Set[str] + state_sets_ids.append(set_ids) + + unpersisted_ids = set() # type: Set[str] + unpersisted_set_ids.append(unpersisted_ids) + + for event_id in state_set.values(): + event_chain = events_to_auth_chain.get(event_id) + if event_chain is not None: + # We have an event in `event_map`. We add all the auth + # events that it references (that aren't also in `event_map`). + set_ids.update(e for e in event_chain if e not in event_map) + + # We also add the full chain of unpersisted event IDs + # referenced by this state set, so that we can work out the + # auth chain difference of the unpersisted events. + unpersisted_ids.update(e for e in event_chain if e in event_map) + else: + set_ids.add(event_id) + + # The auth chain difference of the unpersisted events of the state sets + # is calculated by taking the difference between the union and + # intersections. + union = unpersisted_set_ids[0].union(*unpersisted_set_ids[1:]) + intersection = unpersisted_set_ids[0].intersection(*unpersisted_set_ids[1:]) + + difference_from_event_map = union - intersection # type: Collection[str] + else: + difference_from_event_map = () + state_sets_ids = [set(state_set.values()) for state_set in state_sets] + + difference = await state_res_store.get_auth_chain_difference(state_sets_ids) + difference.update(difference_from_event_map) return difference |