diff options
Diffstat (limited to 'synapse/events')
| -rw-r--r-- | synapse/events/snapshot.py | 159 |
1 files changed, 129 insertions, 30 deletions
diff --git a/synapse/events/snapshot.py b/synapse/events/snapshot.py index a269de5482..64e898f40c 100644 --- a/synapse/events/snapshot.py +++ b/synapse/events/snapshot.py @@ -12,6 +12,8 @@ # 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. +from typing import Dict, Optional, Tuple, Union + from six import iteritems import attr @@ -19,54 +21,113 @@ from frozendict import frozendict from twisted.internet import defer +from synapse.appservice import ApplicationService from synapse.logging.context import make_deferred_yieldable, run_in_background @attr.s(slots=True) class EventContext: """ + Holds information relevant to persisting an event + Attributes: - state_group (int|None): state group id, if the state has been stored - as a state group. This is usually only None if e.g. the event is - an outlier. - rejected (bool|str): A rejection reason if the event was rejected, else - False - - prev_group (int): Previously persisted state group. ``None`` for an - outlier. - delta_ids (dict[(str, str), str]): Delta from ``prev_group``. - (type, state_key) -> event_id. ``None`` for an outlier. - - app_service: FIXME - - _current_state_ids (dict[(str, str), str]|None): - The current state map including the current event. None if outlier - or we haven't fetched the state from DB yet. + 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 + are persisted with a state group which includes the new event, so this is + effectively the state *after* the event in question. + + For a *rejected* state event, where the state of the rejected event is + ignored, this state_group should never make it into the + event_to_state_groups table. Indeed, inspecting this value for a rejected + state event is almost certainly incorrect. + + 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``. + + Note that this *not* (necessarily) the state group associated with + ``_prev_state_ids``. + + delta_ids: If ``prev_group`` is not None, the state delta between ``prev_group`` + and ``state_group``. + + app_service: If this event is being sent by a (local) application service, that + app service. + + _current_state_ids: The room state map, including this event - ie, the state + in ``state_group``. + (type, state_key) -> event_id - _prev_state_ids (dict[(str, str), str]|None): - The current state map excluding the current event. None if outlier - or we haven't fetched the state from DB yet. + FIXME: what is this for an outlier? it seems ill-defined. It seems like + it could be either {}, or the state we were given by the remote + server, depending on $THINGS + + Note that this is a private attribute: it should be accessed via + ``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 - 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! + (type, state_key) -> event_id + + FIXME: again, what is this for an outlier? + + As with _current_state_ids, this is a private attribute. It should be + accessed via get_prev_state_ids. """ - state_group = attr.ib(default=None) - rejected = attr.ib(default=False) - prev_group = attr.ib(default=None) - delta_ids = attr.ib(default=None) - app_service = attr.ib(default=None) + rejected = attr.ib(default=False, type=Union[bool, str]) + _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]) - _prev_state_ids = attr.ib(default=None) - _current_state_ids = attr.ib(default=None) + _current_state_ids = attr.ib( + default=None, type=Optional[Dict[Tuple[str, str], str]] + ) + _prev_state_ids = attr.ib(default=None, type=Optional[Dict[Tuple[str, str], str]]) @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, ) @@ -97,7 +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), @@ -123,6 +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"], @@ -134,22 +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 @@ -163,11 +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 |