354 lines
13 KiB
Python
354 lines
13 KiB
Python
# Copyright 2014-2016 OpenMarket Ltd
|
|
#
|
|
# Licensed under the Apache License, Version 2.0 (the "License");
|
|
# you may not use this file except in compliance with the License.
|
|
# You may obtain a copy of the License at
|
|
#
|
|
# http://www.apache.org/licenses/LICENSE-2.0
|
|
#
|
|
# Unless required by applicable law or agreed to in writing, software
|
|
# distributed under the License is distributed on an "AS IS" BASIS,
|
|
# 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 TYPE_CHECKING, Optional, Union
|
|
|
|
import attr
|
|
from frozendict import frozendict
|
|
|
|
from synapse.appservice import ApplicationService
|
|
from synapse.events import EventBase
|
|
from synapse.logging.context import make_deferred_yieldable, run_in_background
|
|
from synapse.types import StateMap
|
|
|
|
if TYPE_CHECKING:
|
|
from synapse.storage.databases.main import DataStore
|
|
|
|
|
|
@attr.s(slots=True)
|
|
class EventContext:
|
|
"""
|
|
Holds information relevant to persisting an event
|
|
|
|
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
|
|
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
|
|
|
|
For an outlier, this is {}
|
|
|
|
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
|
|
|
|
For an outlier, this is {}
|
|
|
|
As with _current_state_ids, this is a private attribute. It should be
|
|
accessed via get_prev_state_ids.
|
|
"""
|
|
|
|
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[StateMap[str]])
|
|
app_service = attr.ib(default=None, type=Optional[ApplicationService])
|
|
|
|
_current_state_ids = attr.ib(default=None, type=Optional[StateMap[str]])
|
|
_prev_state_ids = attr.ib(default=None, type=Optional[StateMap[str]])
|
|
|
|
@staticmethod
|
|
def with_state(
|
|
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,
|
|
)
|
|
|
|
@staticmethod
|
|
def for_outlier():
|
|
"""Return an EventContext instance suitable for persisting an outlier event"""
|
|
return EventContext(
|
|
current_state_ids={},
|
|
prev_state_ids={},
|
|
)
|
|
|
|
async def serialize(self, event: EventBase, store: "DataStore") -> dict:
|
|
"""Converts self to a type that can be serialized as JSON, and then
|
|
deserialized by `deserialize`
|
|
|
|
Args:
|
|
event (FrozenEvent): The event that this context relates to
|
|
|
|
Returns:
|
|
dict
|
|
"""
|
|
|
|
# We don't serialize the full state dicts, instead they get pulled out
|
|
# of the DB on the other side. However, the other side can't figure out
|
|
# the prev_state_ids, so if we're a state event we include the event
|
|
# id that we replaced in the state.
|
|
if event.is_state():
|
|
prev_state_ids = await self.get_prev_state_ids()
|
|
prev_state_id = prev_state_ids.get((event.type, event.state_key))
|
|
else:
|
|
prev_state_id = None
|
|
|
|
return {
|
|
"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_before_event": self.state_group_before_event,
|
|
"rejected": self.rejected,
|
|
"prev_group": self.prev_group,
|
|
"delta_ids": _encode_state_dict(self.delta_ids),
|
|
"app_service_id": self.app_service.id if self.app_service else None,
|
|
}
|
|
|
|
@staticmethod
|
|
def deserialize(storage, input):
|
|
"""Converts a dict that was produced by `serialize` back into a
|
|
EventContext.
|
|
|
|
Args:
|
|
storage (Storage): Used to convert AS ID to AS object and fetch
|
|
state.
|
|
input (dict): A dict produced by `serialize`
|
|
|
|
Returns:
|
|
EventContext
|
|
"""
|
|
context = _AsyncEventContextImpl(
|
|
# We use the state_group and prev_state_id stuff to pull the
|
|
# current_state_ids out of the DB and construct prev_state_ids.
|
|
storage=storage,
|
|
prev_state_id=input["prev_state_id"],
|
|
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"],
|
|
)
|
|
|
|
app_service_id = input["app_service_id"]
|
|
if app_service_id:
|
|
context.app_service = storage.main.get_app_service_by_id(app_service_id)
|
|
|
|
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
|
|
|
|
async def get_current_state_ids(self) -> Optional[StateMap[str]]:
|
|
"""
|
|
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:
|
|
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")
|
|
|
|
await self._ensure_fetched()
|
|
return self._current_state_ids
|
|
|
|
async def get_prev_state_ids(self):
|
|
"""
|
|
Gets the room state map, excluding this event.
|
|
|
|
For a non-state event, this will be the same as get_current_state_ids().
|
|
|
|
Returns:
|
|
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.
|
|
"""
|
|
await self._ensure_fetched()
|
|
return self._prev_state_ids
|
|
|
|
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
|
|
|
|
async def _ensure_fetched(self):
|
|
return None
|
|
|
|
|
|
@attr.s(slots=True)
|
|
class _AsyncEventContextImpl(EventContext):
|
|
"""
|
|
An implementation of EventContext which fetches _current_state_ids and
|
|
_prev_state_ids from the database on demand.
|
|
|
|
Attributes:
|
|
|
|
_storage (Storage)
|
|
|
|
_fetching_state_deferred (Deferred|None): Resolves when *_state_ids have
|
|
been calculated. None if we haven't started calculating yet
|
|
|
|
_event_type (str): The type of the event the context is associated with.
|
|
|
|
_event_state_key (str): The state_key of the event the context is
|
|
associated with.
|
|
|
|
_prev_state_id (str|None): If the event associated with the context is
|
|
a state event, then `_prev_state_id` is the event_id of the state
|
|
that was replaced.
|
|
"""
|
|
|
|
# This needs to have a default as we're inheriting
|
|
_storage = attr.ib(default=None)
|
|
_prev_state_id = attr.ib(default=None)
|
|
_event_type = attr.ib(default=None)
|
|
_event_state_key = attr.ib(default=None)
|
|
_fetching_state_deferred = attr.ib(default=None)
|
|
|
|
async def _ensure_fetched(self):
|
|
if not self._fetching_state_deferred:
|
|
self._fetching_state_deferred = run_in_background(self._fill_out_state)
|
|
|
|
return await make_deferred_yieldable(self._fetching_state_deferred)
|
|
|
|
async def _fill_out_state(self):
|
|
"""Called to populate the _current_state_ids and _prev_state_ids
|
|
attributes by loading from the database.
|
|
"""
|
|
if self.state_group is None:
|
|
return
|
|
|
|
self._current_state_ids = await self._storage.state.get_state_ids_for_group(
|
|
self.state_group
|
|
)
|
|
if self._event_state_key is not None:
|
|
self._prev_state_ids = dict(self._current_state_ids)
|
|
|
|
key = (self._event_type, self._event_state_key)
|
|
if self._prev_state_id:
|
|
self._prev_state_ids[key] = self._prev_state_id
|
|
else:
|
|
self._prev_state_ids.pop(key, None)
|
|
else:
|
|
self._prev_state_ids = self._current_state_ids
|
|
|
|
|
|
def _encode_state_dict(state_dict):
|
|
"""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):
|
|
"""Decodes a state dict encoded using `_encode_state_dict` above"""
|
|
if input is None:
|
|
return None
|
|
|
|
return frozendict({(etype, state_key): v for etype, state_key, v in input})
|