diff --git a/synapse/state.py b/synapse/state.py
index 9db84c9b5c..1c999e4d79 100644
--- a/synapse/state.py
+++ b/synapse/state.py
@@ -16,11 +16,13 @@
from twisted.internet import defer
-from synapse.federation.pdu_codec import encode_event_id, decode_event_id
from synapse.util.logutils import log_function
+from synapse.util.async import run_on_reactor
+from synapse.api.events.room import RoomPowerLevelsEvent
from collections import namedtuple
+import copy
import logging
import hashlib
@@ -35,230 +37,204 @@ KeyStateTuple = namedtuple("KeyStateTuple", ("context", "type", "state_key"))
class StateHandler(object):
- """ Repsonsible for doing state conflict resolution.
+ """ Responsible for doing state conflict resolution.
"""
def __init__(self, hs):
self.store = hs.get_datastore()
- self._replication = hs.get_replication_layer()
- self.server_name = hs.hostname
@defer.inlineCallbacks
@log_function
- def handle_new_event(self, event, snapshot):
- """ Given an event this works out if a) we have sufficient power level
- to update the state and b) works out what the prev_state should be.
-
- Returns:
- Deferred: Resolved with a boolean indicating if we succesfully
- updated the state.
-
- Raised:
- AuthError
+ def annotate_event_with_state(self, event, old_state=None):
+ """ Annotates the event with the current state events as of that event.
+
+ This method adds three new attributes to the event:
+ * `state_events`: The state up to and including the event. Encoded
+ as a dict mapping tuple (type, state_key) -> event.
+ * `old_state_events`: The state up to, but excluding, the event.
+ Encoded similarly as `state_events`.
+ * `state_group`: If there is an existing state group that can be
+ used, then return that. Otherwise return `None`. See state
+ storage for more information.
+
+ If the argument `old_state` is given (in the form of a list of
+ events), then they are used as a the values for `old_state_events` and
+ the value for `state_events` is generated from it. `state_group` is
+ set to None.
+
+ This needs to be called before persisting the event.
"""
- # This needs to be done in a transaction.
-
- if not hasattr(event, "state_key"):
- return
+ yield run_on_reactor()
- key = KeyStateTuple(
- event.room_id,
- event.type,
- _get_state_key_from_event(event)
- )
+ if old_state:
+ event.state_group = None
+ event.old_state_events = {
+ (s.type, s.state_key): s for s in old_state
+ }
+ event.state_events = event.old_state_events
- # Now I need to fill out the prev state and work out if it has auth
- # (w.r.t. to power levels)
+ if hasattr(event, "state_key"):
+ event.state_events[(event.type, event.state_key)] = event
- snapshot.fill_out_prev_events(event)
+ defer.returnValue(False)
+ return
- event.prev_events = [
- e for e in event.prev_events if e != event.event_id
- ]
+ if hasattr(event, "outlier") and event.outlier:
+ event.state_group = None
+ event.old_state_events = None
+ event.state_events = {}
+ defer.returnValue(False)
+ return
- current_state = snapshot.prev_state_pdu
+ ids = [e for e, _ in event.prev_events]
- if current_state:
- event.prev_state = encode_event_id(
- current_state.pdu_id, current_state.origin
- )
+ ret = yield self.resolve_state_groups(ids)
+ state_group, new_state = ret
- # TODO check current_state to see if the min power level is less
- # than the power level of the user
- # power_level = self._get_power_level_for_event(event)
+ event.old_state_events = copy.deepcopy(new_state)
- pdu_id, origin = decode_event_id(event.event_id, self.server_name)
+ if hasattr(event, "state_key"):
+ key = (event.type, event.state_key)
+ if key in new_state:
+ event.replaces_state = new_state[key].event_id
+ new_state[key] = event
+ elif state_group:
+ event.state_group = state_group
+ event.state_events = new_state
+ defer.returnValue(False)
- yield self.store.update_current_state(
- pdu_id=pdu_id,
- origin=origin,
- context=key.context,
- pdu_type=key.type,
- state_key=key.state_key
- )
+ event.state_group = None
+ event.state_events = new_state
- defer.returnValue(True)
+ defer.returnValue(hasattr(event, "state_key"))
@defer.inlineCallbacks
- @log_function
- def handle_new_state(self, new_pdu):
- """ Apply conflict resolution to `new_pdu`.
+ def get_current_state(self, room_id, event_type=None, state_key=""):
+ """ Returns the current state for the room as a list. This is done by
+ calling `get_latest_events_in_room` to get the leading edges of the
+ event graph and then resolving any of the state conflicts.
- This should be called on every new state pdu, regardless of whether or
- not there is a conflict.
+ This is equivalent to getting the state of an event that were to send
+ next before receiving any new events.
- This function is safe against the race of it getting called with two
- `PDU`s trying to update the same state.
+ If `event_type` is specified, then the method returns only the one
+ event (or None) with that `event_type` and `state_key`.
"""
+ events = yield self.store.get_latest_events_in_room(room_id)
- # This needs to be done in a transaction.
-
- is_new = yield self._handle_new_state(new_pdu)
-
- logger.debug("is_new: %s %s %s", is_new, new_pdu.pdu_id, new_pdu.origin)
+ event_ids = [
+ e_id
+ for e_id, _, _ in events
+ ]
- if is_new:
- yield self.store.update_current_state(
- pdu_id=new_pdu.pdu_id,
- origin=new_pdu.origin,
- context=new_pdu.context,
- pdu_type=new_pdu.pdu_type,
- state_key=new_pdu.state_key
- )
+ res = yield self.resolve_state_groups(event_ids)
- defer.returnValue(is_new)
+ if event_type:
+ defer.returnValue(res[1].get((event_type, state_key)))
+ return
- def _get_power_level_for_event(self, event):
- # return self._persistence.get_power_level_for_user(event.room_id,
- # event.sender)
- return event.power_level
+ defer.returnValue(res[1].values())
@defer.inlineCallbacks
@log_function
- def _handle_new_state(self, new_pdu):
- tree, missing_branch = yield self.store.get_unresolved_state_tree(
- new_pdu
- )
- new_branch, current_branch = tree
+ def resolve_state_groups(self, event_ids):
+ """ Given a list of event_ids this method fetches the state at each
+ event, resolves conflicts between them and returns them.
- logger.debug(
- "_handle_new_state new=%s, current=%s",
- new_branch, current_branch
+ Return format is a tuple: (`state_group`, `state_events`), where the
+ first is the name of a state group if one and only one is involved,
+ otherwise `None`.
+ """
+ state_groups = yield self.store.get_state_groups(
+ event_ids
)
- if missing_branch is not None:
- # We're missing some PDUs. Fetch them.
- # TODO (erikj): Limit this.
- missing_prev = tree[missing_branch][-1]
-
- pdu_id = missing_prev.prev_state_id
- origin = missing_prev.prev_state_origin
-
- is_missing = yield self.store.get_pdu(pdu_id, origin) is None
- if not is_missing:
- raise Exception("Conflict resolution failed")
-
- yield self._replication.get_pdu(
- destination=missing_prev.origin,
- pdu_origin=origin,
- pdu_id=pdu_id,
- outlier=True
- )
-
- updated_current = yield self._handle_new_state(new_pdu)
- defer.returnValue(updated_current)
-
- if not current_branch:
- # There is no current state
- defer.returnValue(True)
- return
-
- n = new_branch[-1]
- c = current_branch[-1]
-
- common_ancestor = n.pdu_id == c.pdu_id and n.origin == c.origin
-
- if common_ancestor:
- # We found a common ancestor!
-
- if len(current_branch) == 1:
- # This is a direct clobber so we can just...
- defer.returnValue(True)
+ group_names = set(state_groups.keys())
+ if len(group_names) == 1:
+ name, state_list = state_groups.items().pop()
+ state = {
+ (e.type, e.state_key): e
+ for e in state_list
+ }
+ defer.returnValue((name, state))
+
+ state = {}
+ for group, g_state in state_groups.items():
+ for s in g_state:
+ state.setdefault(
+ (s.type, s.state_key),
+ {}
+ )[s.event_id] = s
+
+ unconflicted_state = {
+ k: v.values()[0] for k, v in state.items()
+ if len(v.values()) == 1
+ }
+
+ conflicted_state = {
+ k: v.values()
+ for k, v in state.items()
+ if len(v.values()) > 1
+ }
+
+ try:
+ new_state = {}
+ new_state.update(unconflicted_state)
+ for key, events in conflicted_state.items():
+ new_state[key] = self._resolve_state_events(events)
+ except:
+ logger.exception("Failed to resolve state")
+ raise
+
+ defer.returnValue((None, new_state))
+
+ def _get_power_level_from_event_state(self, event, user_id):
+ if hasattr(event, "old_state_events") and event.old_state_events:
+ key = (RoomPowerLevelsEvent.TYPE, "", )
+ power_level_event = event.old_state_events.get(key)
+ level = None
+ if power_level_event:
+ level = power_level_event.content.get("users", {}).get(
+ user_id
+ )
+ if not level:
+ level = power_level_event.content.get("users_default", 0)
+ return level
else:
- # We didn't find a common ancestor. This is probably fine.
- pass
+ return 0
- result = yield self._do_conflict_res(
- new_branch, current_branch, common_ancestor
- )
- defer.returnValue(result)
+ @log_function
+ def _resolve_state_events(self, events):
+ curr_events = events
- @defer.inlineCallbacks
- def _do_conflict_res(self, new_branch, current_branch, common_ancestor):
- conflict_res = [
- self._do_power_level_conflict_res,
- self._do_chain_length_conflict_res,
- self._do_hash_conflict_res,
+ new_powers = [
+ self._get_power_level_from_event_state(e, e.user_id)
+ for e in curr_events
]
- for algo in conflict_res:
- new_res, curr_res = yield defer.maybeDeferred(
- algo,
- new_branch, current_branch, common_ancestor
- )
-
- if new_res < curr_res:
- defer.returnValue(False)
- elif new_res > curr_res:
- defer.returnValue(True)
-
- raise Exception("Conflict resolution failed.")
-
- @defer.inlineCallbacks
- def _do_power_level_conflict_res(self, new_branch, current_branch,
- common_ancestor):
- new_powers_deferreds = []
- for e in new_branch[:-1] if common_ancestor else new_branch:
- if hasattr(e, "user_id"):
- new_powers_deferreds.append(
- self.store.get_power_level(e.context, e.user_id)
- )
-
- current_powers_deferreds = []
- for e in current_branch[:-1] if common_ancestor else current_branch:
- if hasattr(e, "user_id"):
- current_powers_deferreds.append(
- self.store.get_power_level(e.context, e.user_id)
- )
-
- new_powers = yield defer.gatherResults(
- new_powers_deferreds,
- consumeErrors=True
- )
-
- current_powers = yield defer.gatherResults(
- current_powers_deferreds,
- consumeErrors=True
- )
+ new_powers = [
+ int(p) if p else 0 for p in new_powers
+ ]
- max_power_new = max(new_powers)
- max_power_current = max(current_powers)
+ max_power = max(new_powers)
- defer.returnValue(
- (max_power_new, max_power_current)
- )
-
- def _do_chain_length_conflict_res(self, new_branch, current_branch,
- common_ancestor):
- return (len(new_branch), len(current_branch))
+ curr_events = [
+ z[0] for z in zip(curr_events, new_powers)
+ if z[1] == max_power
+ ]
- def _do_hash_conflict_res(self, new_branch, current_branch,
- common_ancestor):
- new_str = "".join([p.pdu_id + p.origin for p in new_branch])
- c_str = "".join([p.pdu_id + p.origin for p in current_branch])
+ if not curr_events:
+ raise RuntimeError("Max didn't get a max?")
+ elif len(curr_events) == 1:
+ return curr_events[0]
+ # TODO: For now, just choose the one with the largest event_id.
return (
- hashlib.sha1(new_str).hexdigest(),
- hashlib.sha1(c_str).hexdigest()
+ sorted(
+ curr_events,
+ key=lambda e: hashlib.sha1(
+ e.event_id + e.user_id + e.room_id + e.type
+ ).hexdigest()
+ )[0]
)
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