diff options
Diffstat (limited to 'synapse/events/snapshot.py')
| -rw-r--r-- | synapse/events/snapshot.py | 174 |
1 files changed, 170 insertions, 4 deletions
diff --git a/synapse/events/snapshot.py b/synapse/events/snapshot.py index 6eaef8b57a..e0d82ad81c 100644 --- a/synapse/events/snapshot.py +++ b/synapse/events/snapshot.py @@ -11,6 +11,7 @@ # 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 abc import ABC, abstractmethod from typing import TYPE_CHECKING, List, Optional, Tuple import attr @@ -26,8 +27,51 @@ if TYPE_CHECKING: from synapse.types.state import StateFilter +class UnpersistedEventContextBase(ABC): + """ + This is a base class for EventContext and UnpersistedEventContext, objects which + hold information relevant to storing an associated event. Note that an + UnpersistedEventContexts must be converted into an EventContext before it is + suitable to send to the db with its associated event. + + Attributes: + _storage: storage controllers for interfacing with the database + app_service: If the associated event is being sent by a (local) application service, that + app service. + """ + + def __init__(self, storage_controller: "StorageControllers"): + self._storage: "StorageControllers" = storage_controller + self.app_service: Optional[ApplicationService] = None + + @abstractmethod + async def persist( + self, + event: EventBase, + ) -> "EventContext": + """ + A method to convert an UnpersistedEventContext to an EventContext, suitable for + sending to the database with the associated event. + """ + pass + + @abstractmethod + async def get_prev_state_ids( + self, state_filter: Optional["StateFilter"] = None + ) -> StateMap[str]: + """ + Gets the room state at the event (ie not including the event if the event is a + state event). + + Args: + state_filter: specifies the type of state event to fetch from DB, example: + EventTypes.JoinRules + """ + pass + + @attr.s(slots=True, auto_attribs=True) -class EventContext: +class EventContext(UnpersistedEventContextBase): """ Holds information relevant to persisting an event @@ -77,9 +121,6 @@ class EventContext: 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. - partial_state: if True, we may be storing this event with a temporary, incomplete state. """ @@ -122,6 +163,9 @@ class EventContext: """Return an EventContext instance suitable for persisting an outlier event""" return EventContext(storage=storage) + async def persist(self, event: EventBase) -> "EventContext": + return self + async def serialize(self, event: EventBase, store: "DataStore") -> JsonDict: """Converts self to a type that can be serialized as JSON, and then deserialized by `deserialize` @@ -254,6 +298,128 @@ class EventContext: ) +@attr.s(slots=True, auto_attribs=True) +class UnpersistedEventContext(UnpersistedEventContextBase): + """ + The event context holds information about the state groups for an event. It is important + to remember that an event technically has two state groups: the state group before the + event, and the state group after the event. If the event is not a state event, the state + group will not change (ie the state group before the event will be the same as the state + group after the event), but if it is a state event the state group before the event + will differ from the state group after the event. + This is a version of an EventContext before the new state group (if any) has been + computed and stored. It contains information about the state before the event (which + also may be the information after the event, if the event is not a state event). The + UnpersistedEventContext must be converted into an EventContext by calling the method + 'persist' on it before it is suitable to be sent to the DB for processing. + + state_group_after_event: + The state group after the event. This will always be None until it is persisted. + If the event is not a state event, this will be the same as + state_group_before_event. + + state_group_before_event: + The ID of the state group representing the state of the room before this event. + + state_delta_due_to_event: + If the event is a state event, then this is the delta of the state between + `state_group` and `state_group_before_event` + + prev_group_for_state_group_before_event: + If it is known, ``state_group_before_event``'s previous state group. + + delta_ids_to_state_group_before_event: + If ``prev_group_for_state_group_before_event`` is not None, the state delta + between ``prev_group_for_state_group_before_event`` and ``state_group_before_event``. + + partial_state: + Whether the event has partial state. + + state_map_before_event: + A map of the state before the event, i.e. the state at `state_group_before_event` + """ + + _storage: "StorageControllers" + state_group_before_event: Optional[int] + state_group_after_event: Optional[int] + state_delta_due_to_event: Optional[dict] + prev_group_for_state_group_before_event: Optional[int] + delta_ids_to_state_group_before_event: Optional[StateMap[str]] + partial_state: bool + state_map_before_event: Optional[StateMap[str]] = None + + async def get_prev_state_ids( + self, state_filter: Optional["StateFilter"] = None + ) -> StateMap[str]: + """ + Gets the room state map, excluding this event. + + Args: + state_filter: specifies the type of state event to fetch from DB + + Returns: + Maps a (type, state_key) to the event ID of the state event matching + this tuple. + """ + if self.state_map_before_event: + return self.state_map_before_event + + assert self.state_group_before_event is not None + return await self._storage.state.get_state_ids_for_group( + self.state_group_before_event, state_filter + ) + + async def persist(self, event: EventBase) -> EventContext: + """ + Creates a full `EventContext` for the event, persisting any referenced state that + has not yet been persisted. + + Args: + event: event that the EventContext is associated with. + + Returns: An EventContext suitable for sending to the database with the event + for persisting + """ + assert self.partial_state is not None + + # If we have a full set of state for before the event but don't have a state + # group for that state, we need to get one + if self.state_group_before_event is None: + assert self.state_map_before_event + state_group_before_event = await self._storage.state.store_state_group( + event.event_id, + event.room_id, + prev_group=self.prev_group_for_state_group_before_event, + delta_ids=self.delta_ids_to_state_group_before_event, + current_state_ids=self.state_map_before_event, + ) + self.state_group_before_event = state_group_before_event + + # if the event isn't a state event the state group doesn't change + if not self.state_delta_due_to_event: + state_group_after_event = self.state_group_before_event + + # otherwise if it is a state event we need to get a state group for it + else: + state_group_after_event = await self._storage.state.store_state_group( + event.event_id, + event.room_id, + prev_group=self.state_group_before_event, + delta_ids=self.state_delta_due_to_event, + current_state_ids=None, + ) + + return EventContext.with_state( + storage=self._storage, + state_group=state_group_after_event, + state_group_before_event=self.state_group_before_event, + state_delta_due_to_event=self.state_delta_due_to_event, + partial_state=self.partial_state, + prev_group=self.state_group_before_event, + delta_ids=self.state_delta_due_to_event, + ) + + def _encode_state_dict( state_dict: Optional[StateMap[str]], ) -> Optional[List[Tuple[str, str, str]]]: |