diff --git a/synapse/events/snapshot.py b/synapse/events/snapshot.py
index acbcbeeced..7c5f620d09 100644
--- a/synapse/events/snapshot.py
+++ b/synapse/events/snapshot.py
@@ -12,104 +12,124 @@
# 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 Optional, Union
from six import iteritems
+import attr
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
+from synapse.types import StateMap
-class EventContext(object):
+@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
-
- push_actions (list[(str, list[object])]): list of (user_id, actions)
- tuples
-
- 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.
-
- prev_state_events (?): XXX: is this ever set to anything other than
- the empty list?
-
- _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.
- (type, state_key) -> event_id
+ 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``.
- _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.
(type, state_key) -> event_id
- _fetching_state_deferred (Deferred|None): Resolves when *_state_ids have
- been calculated. None if we haven't started calculating 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
- _event_type (str): The type of the event the context is associated with.
- Only set when state has not been fetched yet.
+ 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.
- _event_state_key (str|None): The state_key of the event the context is
- associated with. Only set when state has not been fetched yet.
+ _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.
- _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.
- Only set when state has not been fetched yet.
- """
+ Note that it is a completely different thing to prev_group!
- __slots__ = [
- "state_group",
- "rejected",
- "prev_group",
- "delta_ids",
- "prev_state_events",
- "app_service",
- "_current_state_ids",
- "_prev_state_ids",
- "_prev_state_id",
- "_event_type",
- "_event_state_key",
- "_fetching_state_deferred",
- ]
-
- def __init__(self):
- self.prev_state_events = []
- self.rejected = False
- self.app_service = None
+ (type, state_key) -> event_id
- @staticmethod
- def with_state(
- state_group, current_state_ids, prev_state_ids, prev_group=None, delta_ids=None
- ):
- context = EventContext()
+ FIXME: again, what is this for an outlier?
- # The current state including the current event
- context._current_state_ids = current_state_ids
- # The current state excluding the current event
- context._prev_state_ids = prev_state_ids
- context.state_group = state_group
+ As with _current_state_ids, this is a private attribute. It should be
+ accessed via get_prev_state_ids.
+ """
- context._prev_state_id = None
- context._event_type = None
- context._event_state_key = None
- context._fetching_state_deferred = defer.succeed(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[StateMap[str]])
+ app_service = attr.ib(default=None, type=Optional[ApplicationService])
- # A previously persisted state group and a delta between that
- # and this state.
- context.prev_group = prev_group
- context.delta_ids = delta_ids
+ _current_state_ids = attr.ib(default=None, type=Optional[StateMap[str]])
+ _prev_state_ids = attr.ib(default=None, type=Optional[StateMap[str]])
- return context
+ @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,
+ )
@defer.inlineCallbacks
def serialize(self, event, store):
@@ -128,7 +148,7 @@ class EventContext(object):
# 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 = yield self.get_prev_state_ids(store)
+ prev_state_ids = yield self.get_prev_state_ids()
prev_state_id = prev_state_ids.get((event.type, event.state_key))
else:
prev_state_id = None
@@ -137,74 +157,93 @@ class EventContext(object):
"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),
- "prev_state_events": self.prev_state_events,
"app_service_id": self.app_service.id if self.app_service else None,
}
@staticmethod
- def deserialize(store, input):
+ def deserialize(storage, input):
"""Converts a dict that was produced by `serialize` back into a
EventContext.
Args:
- store (DataStore): Used to convert AS ID to AS object
+ storage (Storage): Used to convert AS ID to AS object and fetch
+ state.
input (dict): A dict produced by `serialize`
Returns:
EventContext
"""
- context = 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"],
+ )
- # 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.
- context._prev_state_id = input["prev_state_id"]
- context._event_type = input["event_type"]
- context._event_state_key = input["event_state_key"]
+ app_service_id = input["app_service_id"]
+ if app_service_id:
+ context.app_service = storage.main.get_app_service_by_id(app_service_id)
- context._current_state_ids = None
- context._prev_state_ids = None
- context._fetching_state_deferred = None
+ return context
- context.state_group = input["state_group"]
- context.prev_group = input["prev_group"]
- context.delta_ids = _decode_state_dict(input["delta_ids"])
+ @property
+ def state_group(self) -> Optional[int]:
+ """The ID of the state group for this event.
- context.rejected = input["rejected"]
- context.prev_state_events = input["prev_state_events"]
+ 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.
- app_service_id = input["app_service_id"]
- if app_service_id:
- context.app_service = store.get_app_service_by_id(app_service_id)
+ For an outlier, where we don't have the state at the event, this will be None.
- return context
+ 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
+ def get_current_state_ids(self):
+ """
+ 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")
- if not self._fetching_state_deferred:
- self._fetching_state_deferred = run_in_background(
- self._fill_out_state, store
- )
-
- yield make_deferred_yieldable(self._fetching_state_deferred)
-
+ yield self._ensure_fetched()
return self._current_state_ids
@defer.inlineCallbacks
- def get_prev_state_ids(self, store):
- """Gets the prev state IDs
+ 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:
Deferred[dict[(str, str), str]|None]: Returns None if state_group
@@ -212,65 +251,88 @@ class EventContext(object):
Maps a (type, state_key) to the event ID of the state event matching
this tuple.
"""
-
- if not self._fetching_state_deferred:
- self._fetching_state_deferred = run_in_background(
- self._fill_out_state, store
- )
-
- yield make_deferred_yieldable(self._fetching_state_deferred)
-
+ yield 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
+ def _ensure_fetched(self):
+ return defer.succeed(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)
+
+ def _ensure_fetched(self):
+ if not self._fetching_state_deferred:
+ self._fetching_state_deferred = run_in_background(self._fill_out_state)
+
+ return make_deferred_yieldable(self._fetching_state_deferred)
+
@defer.inlineCallbacks
- def _fill_out_state(self, store):
+ 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 = yield store.get_state_ids_for_group(self.state_group)
- if self._prev_state_id and self._event_state_key is not None:
+ self._current_state_ids = yield 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)
- self._prev_state_ids[key] = self._prev_state_id
+ 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
- @defer.inlineCallbacks
- def update_state(
- self, state_group, prev_state_ids, current_state_ids, prev_group, delta_ids
- ):
- """Replace the state in the context
- """
-
- # We need to make sure we wait for any ongoing fetching of state
- # to complete so that the updated state doesn't get clobbered
- if self._fetching_state_deferred:
- yield make_deferred_yieldable(self._fetching_state_deferred)
-
- self.state_group = state_group
- self._prev_state_ids = prev_state_ids
- self.prev_group = prev_group
- self._current_state_ids = current_state_ids
- self.delta_ids = delta_ids
-
- # We need to ensure that that we've marked as having fetched the state
- self._fetching_state_deferred = defer.succeed(None)
-
def _encode_state_dict(state_dict):
"""Since dicts of (type, state_key) -> event_id cannot be serialized in
|
