Implementation of state rollback in /sync

Implementation of SPEC-254: roll back the state dictionary to how it looked at
the start of the timeline.

Merged PR https://github.com/matrix-org/synapse/pull/373
This commit is contained in:
Richard van der Hoff 2015-11-10 18:29:25 +00:00
parent fddedd51d9
commit e4d622aaaf
2 changed files with 69 additions and 4 deletions

View File

@ -20,6 +20,7 @@ from synapse.http.servlet import (
)
from synapse.handlers.sync import SyncConfig
from synapse.types import StreamToken
from synapse.events import FrozenEvent
from synapse.events.utils import (
serialize_event, format_event_for_client_v2_without_event_id,
)
@ -256,7 +257,13 @@ class SyncRestServlet(RestServlet):
:rtype: dict[str, object]
"""
event_map = {}
state_events = filter.filter_room_state(room.state.values())
state_dict = room.state
timeline_events = filter.filter_room_timeline(room.timeline.events)
state_dict = SyncRestServlet._rollback_state_for_timeline(
state_dict, timeline_events)
state_events = filter.filter_room_state(state_dict.values())
state_event_ids = []
for event in state_events:
# TODO(mjark): Respect formatting requirements in the filter.
@ -266,7 +273,6 @@ class SyncRestServlet(RestServlet):
)
state_event_ids.append(event.event_id)
timeline_events = filter.filter_room_timeline(room.timeline.events)
timeline_event_ids = []
for event in timeline_events:
# TODO(mjark): Respect formatting requirements in the filter.
@ -297,6 +303,63 @@ class SyncRestServlet(RestServlet):
return result
@staticmethod
def _rollback_state_for_timeline(state, timeline):
"""
Wind the state dictionary backwards, so that it represents the
state at the start of the timeline, rather than at the end.
:param dict[(str, str), synapse.events.EventBase] state: the
state dictionary. Will be updated to the state before the timeline.
:param list[synapse.events.EventBase] timeline: the event timeline
:return: updated state dictionary
"""
logger.debug("Processing state dict %r; timeline %r", state,
[e.get_dict() for e in timeline])
result = state.copy()
for timeline_event in reversed(timeline):
if not timeline_event.is_state():
continue
event_key = (timeline_event.type, timeline_event.state_key)
logger.debug("Considering %s for removal", event_key)
state_event = result.get(event_key)
if (state_event is None or
state_event.event_id != timeline_event.event_id):
# the event in the timeline isn't present in the state
# dictionary.
#
# the most likely cause for this is that there was a fork in
# the event graph, and the state is no longer valid. Really,
# the event shouldn't be in the timeline. We're going to ignore
# it for now, however.
logger.warn("Found state event %r in timeline which doesn't "
"match state dictionary", timeline_event)
continue
prev_event_id = timeline_event.unsigned.get("replaces_state", None)
logger.debug("Replacing %s with %s in state dict",
timeline_event.event_id, prev_event_id)
if prev_event_id is None:
del result[event_key]
else:
result[event_key] = FrozenEvent({
"type": timeline_event.type,
"state_key": timeline_event.state_key,
"content": timeline_event.unsigned['prev_content'],
"sender": timeline_event.unsigned['prev_sender'],
"event_id": prev_event_id,
"room_id": timeline_event.room_id,
})
logger.debug("New value: %r", result.get(event_key))
return result
def register_servlets(hs, http_server):
SyncRestServlet(hs).register(http_server)

View File

@ -831,7 +831,8 @@ class EventsStore(SQLBaseStore):
allow_none=True,
)
if prev:
ev.unsigned["prev_content"] = prev.get_dict()["content"]
ev.unsigned["prev_content"] = prev.content
ev.unsigned["prev_sender"] = prev.sender
self._get_event_cache.prefill(
(ev.event_id, check_redacted, get_prev_content), ev
@ -888,7 +889,8 @@ class EventsStore(SQLBaseStore):
get_prev_content=False,
)
if prev:
ev.unsigned["prev_content"] = prev.get_dict()["content"]
ev.unsigned["prev_content"] = prev.content
ev.unsigned["prev_sender"] = prev.sender
self._get_event_cache.prefill(
(ev.event_id, check_redacted, get_prev_content), ev