diff options
Diffstat (limited to 'synapse/events/snapshot.py')
| -rw-r--r-- | synapse/events/snapshot.py | 74 |
1 files changed, 67 insertions, 7 deletions
diff --git a/synapse/events/snapshot.py b/synapse/events/snapshot.py index 5f07f6fe4b..64e898f40c 100644 --- a/synapse/events/snapshot.py +++ b/synapse/events/snapshot.py @@ -33,7 +33,7 @@ class EventContext: Attributes: rejected: A rejection reason if the event was rejected, else False - state_group: The ID of the state group for this event. Note that state events + _state_group: The ID of the state group for this event. Note that state events are persisted with a state group which includes the new event, so this is effectively the state *after* the event in question. @@ -45,10 +45,24 @@ class EventContext: For an outlier, where we don't have the state at the event, this will be None. + Note that this is a private attribute: it should be accessed via + the ``state_group`` property. + + state_group_before_event: The ID of the state group representing the state + of the room before this event. + + If this is a non-state event, this will be the same as ``state_group``. If + it's a state event, it will be the same as ``prev_group``. + + If ``state_group`` is None (ie, the event is an outlier), + ``state_group_before_event`` will always also be ``None``. + prev_group: If it is known, ``state_group``'s prev_group. Note that this being None does not necessarily mean that ``state_group`` does not have a prev_group! + If the event is a state event, this is normally the same as ``prev_group``. + If ``state_group`` is None (ie, the event is an outlier), ``prev_group`` will always also be ``None``. @@ -74,7 +88,8 @@ class EventContext: ``get_current_state_ids``. _AsyncEventContext impl calculates this on-demand: it will be None until that happens. - _prev_state_ids: The room state map, excluding this event. For a non-state + _prev_state_ids: The room state map, excluding this event - ie, the state + in ``state_group_before_event``. For a non-state event, this will be the same as _current_state_events. Note that it is a completely different thing to prev_group! @@ -88,7 +103,8 @@ class EventContext: """ rejected = attr.ib(default=False, type=Union[bool, str]) - state_group = attr.ib(default=None, type=Optional[int]) + _state_group = attr.ib(default=None, type=Optional[int]) + state_group_before_event = attr.ib(default=None, type=Optional[int]) prev_group = attr.ib(default=None, type=Optional[int]) delta_ids = attr.ib(default=None, type=Optional[Dict[Tuple[str, str], str]]) app_service = attr.ib(default=None, type=Optional[ApplicationService]) @@ -100,12 +116,18 @@ class EventContext: @staticmethod def with_state( - state_group, current_state_ids, prev_state_ids, prev_group=None, delta_ids=None + state_group, + state_group_before_event, + current_state_ids, + prev_state_ids, + prev_group=None, + delta_ids=None, ): return EventContext( current_state_ids=current_state_ids, prev_state_ids=prev_state_ids, state_group=state_group, + state_group_before_event=state_group_before_event, prev_group=prev_group, delta_ids=delta_ids, ) @@ -136,7 +158,8 @@ class EventContext: "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, + "state_group": self._state_group, + "state_group_before_event": self.state_group_before_event, "rejected": self.rejected, "prev_group": self.prev_group, "delta_ids": _encode_state_dict(self.delta_ids), @@ -162,6 +185,7 @@ class EventContext: event_type=input["event_type"], event_state_key=input["event_state_key"], state_group=input["state_group"], + state_group_before_event=input["state_group_before_event"], prev_group=input["prev_group"], delta_ids=_decode_state_dict(input["delta_ids"]), rejected=input["rejected"], @@ -173,22 +197,52 @@ class EventContext: return context + @property + def state_group(self) -> Optional[int]: + """The ID of the state group for this event. + + Note that state events are persisted with a state group which includes the new + event, so this is effectively the state *after* the event in question. + + For an outlier, where we don't have the state at the event, this will be None. + + It is an error to access this for a rejected event, since rejected state should + not make it into the room state. Accessing this property will raise an exception + if ``rejected`` is set. + """ + if self.rejected: + raise RuntimeError("Attempt to access state_group of rejected event") + + return self._state_group + @defer.inlineCallbacks def get_current_state_ids(self, store): - """Gets the current state IDs + """ + Gets the room state map, including this event - ie, the state in ``state_group`` + + It is an error to access this for a rejected event, since rejected state should + not make it into the room state. This method will raise an exception if + ``rejected`` is set. Returns: Deferred[dict[(str, str), str]|None]: Returns None if state_group is None, which happens when the associated event is an outlier. + Maps a (type, state_key) to the event ID of the state event matching this tuple. """ + if self.rejected: + raise RuntimeError("Attempt to access state_ids of rejected event") + yield self._ensure_fetched(store) return self._current_state_ids @defer.inlineCallbacks def get_prev_state_ids(self, store): - """Gets the prev state IDs + """ + Gets the room state map, excluding this event. + + For a non-state event, this will be the same as get_current_state_ids(). Returns: Deferred[dict[(str, str), str]|None]: Returns None if state_group @@ -202,11 +256,17 @@ class EventContext: def get_cached_current_state_ids(self): """Gets the current state IDs if we have them already cached. + It is an error to access this for a rejected event, since rejected state should + not make it into the room state. This method will raise an exception if + ``rejected`` is set. + Returns: dict[(str, str), str]|None: Returns None if we haven't cached the state or if state_group is None, which happens when the associated event is an outlier. """ + if self.rejected: + raise RuntimeError("Attempt to access state_ids of rejected event") return self._current_state_ids |