547 lines
		
	
	
		
			21 KiB
		
	
	
	
		
			Python
		
	
	
			
		
		
	
	
			547 lines
		
	
	
		
			21 KiB
		
	
	
	
		
			Python
		
	
	
| # Copyright 2014-2016 OpenMarket Ltd
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| #
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| # Licensed under the Apache License, Version 2.0 (the "License");
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| # you may not use this file except in compliance with the License.
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| # You may obtain a copy of the License at
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| #
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| #     http://www.apache.org/licenses/LICENSE-2.0
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| #
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| # Unless required by applicable law or agreed to in writing, software
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| # distributed under the License is distributed on an "AS IS" BASIS,
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| # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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| # See the License for the specific language governing permissions and
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| # limitations under the License.
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| from abc import ABC, abstractmethod
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| from typing import TYPE_CHECKING, Dict, List, Optional, Tuple
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| 
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| import attr
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| from immutabledict import immutabledict
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| 
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| from synapse.appservice import ApplicationService
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| from synapse.events import EventBase
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| from synapse.logging.opentracing import tag_args, trace
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| from synapse.types import JsonDict, StateMap
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| 
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| if TYPE_CHECKING:
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|     from synapse.storage.controllers import StorageControllers
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|     from synapse.storage.databases import StateGroupDataStore
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|     from synapse.storage.databases.main import DataStore
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|     from synapse.types.state import StateFilter
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| 
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| 
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| class UnpersistedEventContextBase(ABC):
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|     """
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|     This is a base class for EventContext and UnpersistedEventContext, objects which
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|     hold information relevant to storing an associated event. Note that an
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|     UnpersistedEventContexts must be converted into an EventContext before it is
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|     suitable to send to the db with its associated event.
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| 
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|     Attributes:
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|         _storage: storage controllers for interfacing with the database
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|         app_service: If the associated event is being sent by a (local) application service, that
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|             app service.
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|     """
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| 
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|     def __init__(self, storage_controller: "StorageControllers"):
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|         self._storage: "StorageControllers" = storage_controller
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|         self.app_service: Optional[ApplicationService] = None
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| 
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|     @abstractmethod
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|     async def persist(
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|         self,
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|         event: EventBase,
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|     ) -> "EventContext":
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|         """
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|         A method to convert an UnpersistedEventContext to an EventContext, suitable for
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|         sending to the database with the associated event.
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|         """
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| 
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|     @abstractmethod
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|     async def get_prev_state_ids(
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|         self, state_filter: Optional["StateFilter"] = None
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|     ) -> StateMap[str]:
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|         """
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|         Gets the room state at the event (ie not including the event if the event is a
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|         state event).
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| 
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|         Args:
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|             state_filter: specifies the type of state event to fetch from DB, example:
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|             EventTypes.JoinRules
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|         """
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| 
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| 
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| @attr.s(slots=True, auto_attribs=True)
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| class EventContext(UnpersistedEventContextBase):
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|     """
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|     Holds information relevant to persisting an event
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| 
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|     Attributes:
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|         rejected: A rejection reason if the event was rejected, else None
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| 
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|         _state_group: The ID of the state group for this event. Note that state events
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|             are persisted with a state group which includes the new event, so this is
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|             effectively the state *after* the event in question.
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| 
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|             For a *rejected* state event, where the state of the rejected event is
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|             ignored, this state_group should never make it into the
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|             event_to_state_groups table. Indeed, inspecting this value for a rejected
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|             state event is almost certainly incorrect.
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| 
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|             For an outlier, where we don't have the state at the event, this will be
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|             None.
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| 
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|             Note that this is a private attribute: it should be accessed via
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|             the ``state_group`` property.
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| 
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|         state_group_before_event: The ID of the state group representing the state
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|             of the room before this event.
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| 
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|             If this is a non-state event, this will be the same as ``state_group``. If
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|             it's a state event, it will be the same as ``prev_group``.
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| 
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|             If ``state_group`` is None (ie, the event is an outlier),
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|             ``state_group_before_event`` will always also be ``None``.
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| 
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|         state_delta_due_to_event: If `state_group` and `state_group_before_event` are not None
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|             then this is the delta of the state between the two groups.
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| 
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|         state_group_deltas: If not empty, this is a dict collecting a mapping of the state
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|             difference between state groups.
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| 
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|             The keys are a tuple of two integers: the initial group and final state group.
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|             The corresponding value is a state map representing the state delta between
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|             these state groups.
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| 
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|             The dictionary is expected to have at most two entries with state groups of:
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| 
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|             1. The state group before the event and after the event.
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|             2. The state group preceding the state group before the event and the
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|                state group before the event.
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| 
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|             This information is collected and stored as part of an optimization for persisting
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|             events.
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| 
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|         partial_state: if True, we may be storing this event with a temporary,
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|             incomplete state.
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|     """
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| 
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|     _storage: "StorageControllers"
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|     state_group_deltas: Dict[Tuple[int, int], StateMap[str]]
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|     rejected: Optional[str] = None
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|     _state_group: Optional[int] = None
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|     state_group_before_event: Optional[int] = None
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|     _state_delta_due_to_event: Optional[StateMap[str]] = None
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|     app_service: Optional[ApplicationService] = None
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| 
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|     partial_state: bool = False
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| 
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|     @staticmethod
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|     def with_state(
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|         storage: "StorageControllers",
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|         state_group: Optional[int],
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|         state_group_before_event: Optional[int],
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|         state_delta_due_to_event: Optional[StateMap[str]],
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|         partial_state: bool,
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|         state_group_deltas: Dict[Tuple[int, int], StateMap[str]],
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|     ) -> "EventContext":
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|         return EventContext(
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|             storage=storage,
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|             state_group=state_group,
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|             state_group_before_event=state_group_before_event,
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|             state_delta_due_to_event=state_delta_due_to_event,
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|             state_group_deltas=state_group_deltas,
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|             partial_state=partial_state,
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|         )
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| 
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|     @staticmethod
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|     def for_outlier(
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|         storage: "StorageControllers",
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|     ) -> "EventContext":
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|         """Return an EventContext instance suitable for persisting an outlier event"""
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|         return EventContext(storage=storage, state_group_deltas={})
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| 
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|     async def persist(self, event: EventBase) -> "EventContext":
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|         return self
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| 
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|     async def serialize(self, event: EventBase, store: "DataStore") -> JsonDict:
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|         """Converts self to a type that can be serialized as JSON, and then
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|         deserialized by `deserialize`
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| 
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|         Args:
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|             event: The event that this context relates to
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| 
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|         Returns:
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|             The serialized event.
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|         """
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| 
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|         return {
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|             "state_group": self._state_group,
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|             "state_group_before_event": self.state_group_before_event,
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|             "rejected": self.rejected,
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|             "state_group_deltas": _encode_state_group_delta(self.state_group_deltas),
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|             "state_delta_due_to_event": _encode_state_dict(
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|                 self._state_delta_due_to_event
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|             ),
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|             "app_service_id": self.app_service.id if self.app_service else None,
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|             "partial_state": self.partial_state,
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|         }
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| 
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|     @staticmethod
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|     def deserialize(storage: "StorageControllers", input: JsonDict) -> "EventContext":
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|         """Converts a dict that was produced by `serialize` back into a
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|         EventContext.
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| 
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|         Args:
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|             storage: Used to convert AS ID to AS object and fetch state.
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|             input: A dict produced by `serialize`
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| 
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|         Returns:
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|             The event context.
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|         """
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| 
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|         context = EventContext(
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|             # We use the state_group and prev_state_id stuff to pull the
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|             # current_state_ids out of the DB and construct prev_state_ids.
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|             storage=storage,
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|             state_group=input["state_group"],
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|             state_group_before_event=input["state_group_before_event"],
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|             state_group_deltas=_decode_state_group_delta(input["state_group_deltas"]),
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|             state_delta_due_to_event=_decode_state_dict(
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|                 input["state_delta_due_to_event"]
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|             ),
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|             rejected=input["rejected"],
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|             partial_state=input.get("partial_state", False),
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|         )
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| 
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|         app_service_id = input["app_service_id"]
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|         if app_service_id:
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|             context.app_service = storage.main.get_app_service_by_id(app_service_id)
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| 
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|         return context
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| 
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|     @property
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|     def state_group(self) -> Optional[int]:
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|         """The ID of the state group for this event.
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| 
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|         Note that state events are persisted with a state group which includes the new
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|         event, so this is effectively the state *after* the event in question.
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| 
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|         For an outlier, where we don't have the state at the event, this will be None.
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| 
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|         It is an error to access this for a rejected event, since rejected state should
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|         not make it into the room state. Accessing this property will raise an exception
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|         if ``rejected`` is set.
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|         """
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|         if self.rejected:
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|             raise RuntimeError("Attempt to access state_group of rejected event")
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| 
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|         return self._state_group
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| 
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|     @trace
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|     @tag_args
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|     async def get_current_state_ids(
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|         self, state_filter: Optional["StateFilter"] = None
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|     ) -> Optional[StateMap[str]]:
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|         """
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|         Gets the room state map, including this event - ie, the state in ``state_group``
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| 
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|         It is an error to access this for a rejected event, since rejected state should
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|         not make it into the room state. This method will raise an exception if
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|         ``rejected`` is set.
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| 
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|         Arg:
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|            state_filter: specifies the type of state event to fetch from DB, example: EventTypes.JoinRules
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| 
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|         Returns:
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|             Returns None if state_group is None, which happens when the associated
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|             event is an outlier.
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| 
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|             Maps a (type, state_key) to the event ID of the state event matching
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|             this tuple.
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|         """
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|         if self.rejected:
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|             raise RuntimeError("Attempt to access state_ids of rejected event")
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| 
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|         assert self._state_delta_due_to_event is not None
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| 
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|         prev_state_ids = await self.get_prev_state_ids(state_filter)
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| 
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|         if self._state_delta_due_to_event:
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|             prev_state_ids = dict(prev_state_ids)
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|             prev_state_ids.update(self._state_delta_due_to_event)
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| 
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|         return prev_state_ids
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| 
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|     @trace
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|     @tag_args
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|     async def get_prev_state_ids(
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|         self, state_filter: Optional["StateFilter"] = None
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|     ) -> StateMap[str]:
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|         """
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|         Gets the room state map, excluding this event.
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| 
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|         For a non-state event, this will be the same as get_current_state_ids().
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| 
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|         Args:
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|             state_filter: specifies the type of state event to fetch from DB, example: EventTypes.JoinRules
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| 
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|         Returns:
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|             Returns {} if state_group is None, which happens when the associated
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|             event is an outlier.
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| 
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|             Maps a (type, state_key) to the event ID of the state event matching
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|             this tuple.
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|         """
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| 
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|         assert self.state_group_before_event is not None
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|         return await self._storage.state.get_state_ids_for_group(
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|             self.state_group_before_event, state_filter
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|         )
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| 
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| 
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| @attr.s(slots=True, auto_attribs=True)
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| class UnpersistedEventContext(UnpersistedEventContextBase):
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|     """
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|     The event context holds information about the state groups for an event. It is important
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|     to remember that an event technically has two state groups: the state group before the
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|     event, and the state group after the event. If the event is not a state event, the state
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|     group will not change (ie the state group before the event will be the same as the state
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|     group after the event), but if it is a state event the state group before the event
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|     will differ from the state group after the event.
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|     This is a version of an EventContext before the new state group (if any) has been
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|     computed and stored. It contains information about the state before the event (which
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|     also may be the information after the event, if the event is not a state event). The
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|     UnpersistedEventContext must be converted into an EventContext by calling the method
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|     'persist' on it before it is suitable to be sent to the DB for processing.
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| 
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|         state_group_after_event:
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|              The state group after the event. This will always be None until it is persisted.
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|              If the event is not a state event, this will be the same as
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|              state_group_before_event.
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| 
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|         state_group_before_event:
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|             The ID of the state group representing the state of the room before this event.
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| 
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|         state_delta_due_to_event:
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|             If the event is a state event, then this is the delta of the state between
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|              `state_group` and `state_group_before_event`
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| 
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|         prev_group_for_state_group_before_event:
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|             If it is known, ``state_group_before_event``'s previous state group.
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| 
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|         delta_ids_to_state_group_before_event:
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|              If ``prev_group_for_state_group_before_event`` is not None, the state delta
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|              between ``prev_group_for_state_group_before_event`` and ``state_group_before_event``.
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| 
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|         partial_state:
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|             Whether the event has partial state.
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| 
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|         state_map_before_event:
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|             A map of the state before the event, i.e. the state at `state_group_before_event`
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|     """
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| 
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|     _storage: "StorageControllers"
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|     state_group_before_event: Optional[int]
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|     state_group_after_event: Optional[int]
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|     state_delta_due_to_event: Optional[StateMap[str]]
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|     prev_group_for_state_group_before_event: Optional[int]
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|     delta_ids_to_state_group_before_event: Optional[StateMap[str]]
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|     partial_state: bool
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|     state_map_before_event: Optional[StateMap[str]] = None
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| 
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|     @classmethod
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|     async def batch_persist_unpersisted_contexts(
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|         cls,
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|         events_and_context: List[Tuple[EventBase, "UnpersistedEventContextBase"]],
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|         room_id: str,
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|         last_known_state_group: int,
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|         datastore: "StateGroupDataStore",
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|     ) -> List[Tuple[EventBase, EventContext]]:
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|         """
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|         Takes a list of events and their associated unpersisted contexts and persists
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|         the unpersisted contexts, returning a list of events and persisted contexts.
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|         Note that all the events must be in a linear chain (ie a <- b <- c).
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| 
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|         Args:
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|             events_and_context: A list of events and their unpersisted contexts
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|             room_id: the room_id for the events
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|             last_known_state_group: the last persisted state group
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|             datastore: a state datastore
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|         """
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|         amended_events_and_context = await datastore.store_state_deltas_for_batched(
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|             events_and_context, room_id, last_known_state_group
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|         )
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| 
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|         events_and_persisted_context = []
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|         for event, unpersisted_context in amended_events_and_context:
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|             state_group_deltas = unpersisted_context._build_state_group_deltas()
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| 
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|             context = EventContext(
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|                 storage=unpersisted_context._storage,
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|                 state_group=unpersisted_context.state_group_after_event,
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|                 state_group_before_event=unpersisted_context.state_group_before_event,
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|                 state_delta_due_to_event=unpersisted_context.state_delta_due_to_event,
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|                 partial_state=unpersisted_context.partial_state,
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|                 state_group_deltas=state_group_deltas,
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|             )
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|             events_and_persisted_context.append((event, context))
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|         return events_and_persisted_context
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| 
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|     async def get_prev_state_ids(
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|         self, state_filter: Optional["StateFilter"] = None
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|     ) -> StateMap[str]:
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|         """
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|         Gets the room state map, excluding this event.
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| 
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|         Args:
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|             state_filter: specifies the type of state event to fetch from DB
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| 
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|         Returns:
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|             Maps a (type, state_key) to the event ID of the state event matching
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|             this tuple.
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|         """
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|         if self.state_map_before_event:
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|             return self.state_map_before_event
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| 
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|         assert self.state_group_before_event is not None
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|         return await self._storage.state.get_state_ids_for_group(
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|             self.state_group_before_event, state_filter
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|         )
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| 
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|     async def persist(self, event: EventBase) -> EventContext:
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|         """
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|         Creates a full `EventContext` for the event, persisting any referenced state that
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|         has not yet been persisted.
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| 
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|         Args:
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|              event: event that the EventContext is associated with.
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| 
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|         Returns: An EventContext suitable for sending to the database with the event
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|         for persisting
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|         """
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|         assert self.partial_state is not None
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| 
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|         # If we have a full set of state for before the event but don't have a state
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|         # group for that state, we need to get one
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|         if self.state_group_before_event is None:
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|             assert self.state_map_before_event
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|             state_group_before_event = await self._storage.state.store_state_group(
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|                 event.event_id,
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|                 event.room_id,
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|                 prev_group=self.prev_group_for_state_group_before_event,
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|                 delta_ids=self.delta_ids_to_state_group_before_event,
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|                 current_state_ids=self.state_map_before_event,
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|             )
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|             self.state_group_before_event = state_group_before_event
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| 
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|         # if the event isn't a state event the state group doesn't change
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|         if not self.state_delta_due_to_event:
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|             self.state_group_after_event = self.state_group_before_event
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| 
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|         # otherwise if it is a state event we need to get a state group for it
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|         else:
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|             self.state_group_after_event = await self._storage.state.store_state_group(
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|                 event.event_id,
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|                 event.room_id,
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|                 prev_group=self.state_group_before_event,
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|                 delta_ids=self.state_delta_due_to_event,
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|                 current_state_ids=None,
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|             )
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| 
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|         state_group_deltas = self._build_state_group_deltas()
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| 
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|         return EventContext.with_state(
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|             storage=self._storage,
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|             state_group=self.state_group_after_event,
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|             state_group_before_event=self.state_group_before_event,
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|             state_delta_due_to_event=self.state_delta_due_to_event,
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|             state_group_deltas=state_group_deltas,
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|             partial_state=self.partial_state,
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|         )
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| 
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|     def _build_state_group_deltas(self) -> Dict[Tuple[int, int], StateMap]:
 | |
|         """
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|         Collect deltas between the state groups associated with this context
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|         """
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|         state_group_deltas = {}
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| 
 | |
|         # if we know the state group before the event and after the event, add them and the
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|         # state delta between them to state_group_deltas
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|         if self.state_group_before_event and self.state_group_after_event:
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|             # if we have the state groups we should have the delta
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|             assert self.state_delta_due_to_event is not None
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|             state_group_deltas[
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|                 (
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|                     self.state_group_before_event,
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|                     self.state_group_after_event,
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|                 )
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|             ] = self.state_delta_due_to_event
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| 
 | |
|         # the state group before the event may also have a state group which precedes it, if
 | |
|         # we have that and the state group before the event, add them and the state
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|         # delta between them to state_group_deltas
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|         if (
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|             self.prev_group_for_state_group_before_event
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|             and self.state_group_before_event
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|         ):
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|             # if we have both state groups we should have the delta between them
 | |
|             assert self.delta_ids_to_state_group_before_event is not None
 | |
|             state_group_deltas[
 | |
|                 (
 | |
|                     self.prev_group_for_state_group_before_event,
 | |
|                     self.state_group_before_event,
 | |
|                 )
 | |
|             ] = self.delta_ids_to_state_group_before_event
 | |
| 
 | |
|         return state_group_deltas
 | |
| 
 | |
| 
 | |
| def _encode_state_group_delta(
 | |
|     state_group_delta: Dict[Tuple[int, int], StateMap[str]]
 | |
| ) -> List[Tuple[int, int, Optional[List[Tuple[str, str, str]]]]]:
 | |
|     if not state_group_delta:
 | |
|         return []
 | |
| 
 | |
|     state_group_delta_encoded = []
 | |
|     for key, value in state_group_delta.items():
 | |
|         state_group_delta_encoded.append((key[0], key[1], _encode_state_dict(value)))
 | |
| 
 | |
|     return state_group_delta_encoded
 | |
| 
 | |
| 
 | |
| def _decode_state_group_delta(
 | |
|     input: List[Tuple[int, int, List[Tuple[str, str, str]]]]
 | |
| ) -> Dict[Tuple[int, int], StateMap[str]]:
 | |
|     if not input:
 | |
|         return {}
 | |
| 
 | |
|     state_group_deltas = {}
 | |
|     for state_group_1, state_group_2, state_dict in input:
 | |
|         state_map = _decode_state_dict(state_dict)
 | |
|         assert state_map is not None
 | |
|         state_group_deltas[(state_group_1, state_group_2)] = state_map
 | |
| 
 | |
|     return state_group_deltas
 | |
| 
 | |
| 
 | |
| def _encode_state_dict(
 | |
|     state_dict: Optional[StateMap[str]],
 | |
| ) -> Optional[List[Tuple[str, str, str]]]:
 | |
|     """Since dicts of (type, state_key) -> event_id cannot be serialized in
 | |
|     JSON we need to convert them to a form that can.
 | |
|     """
 | |
|     if state_dict is None:
 | |
|         return None
 | |
| 
 | |
|     return [(etype, state_key, v) for (etype, state_key), v in state_dict.items()]
 | |
| 
 | |
| 
 | |
| def _decode_state_dict(
 | |
|     input: Optional[List[Tuple[str, str, str]]]
 | |
| ) -> Optional[StateMap[str]]:
 | |
|     """Decodes a state dict encoded using `_encode_state_dict` above"""
 | |
|     if input is None:
 | |
|         return None
 | |
| 
 | |
|     return immutabledict({(etype, state_key): v for etype, state_key, v in input})
 |