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# -*- coding: utf-8 -*-
# Copyright 2014 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 twisted.internet import defer
from synapse.util.logutils import log_function
from synapse.util.async import run_on_reactor
from collections import namedtuple
import copy
import logging
import hashlib
logger = logging.getLogger(__name__)
def _get_state_key_from_event(event):
return event.state_key
KeyStateTuple = namedtuple("KeyStateTuple", ("context", "type", "state_key"))
class StateHandler(object):
""" 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
self.hs = hs
@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 successfully
updated the state.
Raised:
AuthError
"""
# This needs to be done in a transaction.
if not hasattr(event, "state_key"):
return
# Now I need to fill out the prev state and work out if it has auth
# (w.r.t. to power levels)
snapshot.fill_out_prev_events(event)
yield self.annotate_state_groups(event)
if event.old_state_events:
current_state = event.old_state_events.get(
(event.type, event.state_key)
)
if current_state:
event.prev_state = current_state.event_id
defer.returnValue(True)
@defer.inlineCallbacks
@log_function
def annotate_state_groups(self, event, old_state=None):
yield run_on_reactor()
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
if hasattr(event, "state_key"):
event.state_events[(event.type, event.state_key)] = event
defer.returnValue(False)
return
if hasattr(event, "outlier") and event.outlier:
event.state_group = None
event.old_state_events = None
event.state_events = {}
defer.returnValue(False)
return
new_state = yield self.resolve_state_groups(
[e for e, _ in event.prev_events]
)
event.old_state_events = copy.deepcopy(new_state)
if hasattr(event, "state_key"):
new_state[(event.type, event.state_key)] = event
event.state_group = None
event.state_events = new_state
defer.returnValue(hasattr(event, "state_key"))
@defer.inlineCallbacks
def get_current_state(self, room_id, event_type=None, state_key=""):
events = yield self.store.get_latest_events_in_room(room_id)
event_ids = [
e_id
for e_id, _, _ in events
]
res = yield self.resolve_state_groups(event_ids)
if event_type:
defer.returnValue(res.get((event_type, state_key)))
return
defer.returnValue(res.values())
@defer.inlineCallbacks
@log_function
def resolve_state_groups(self, event_ids):
state_groups = yield self.store.get_state_groups(
event_ids
)
state = {}
for group in state_groups:
for s in group.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] = yield self._resolve_state_events(events)
except:
logger.exception("Failed to resolve state")
raise
defer.returnValue(new_state)
@defer.inlineCallbacks
@log_function
def _resolve_state_events(self, events):
curr_events = events
new_powers_deferreds = []
for e in curr_events:
new_powers_deferreds.append(
self.store.get_power_level(e.room_id, e.user_id)
)
new_powers = yield defer.gatherResults(
new_powers_deferreds,
consumeErrors=True
)
max_power = max([int(p) for p in new_powers])
curr_events = [
z[0] for z in zip(curr_events, new_powers)
if int(z[1]) == max_power
]
if not curr_events:
raise RuntimeError("Max didn't get a max?")
elif len(curr_events) == 1:
defer.returnValue(curr_events[0])
# TODO: For now, just choose the one with the largest event_id.
defer.returnValue(
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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