synapse-product/synapse/state.py

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# -*- coding: utf-8 -*-
# Copyright 2014 OpenMarket Ltd
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#
# 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.
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from twisted.internet import defer
from synapse.util.logutils import log_function
from synapse.util.async import run_on_reactor
from synapse.api.events.room import RoomPowerLevelsEvent
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from collections import namedtuple
import copy
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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):
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""" Responsible for doing state conflict resolution.
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"""
def __init__(self, hs):
self.store = hs.get_datastore()
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@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
ids = [e for e, _ in event.prev_events]
ret = yield self.resolve_state_groups(ids)
state_group, new_state = ret
event.old_state_events = copy.deepcopy(new_state)
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)
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[1].get((event_type, state_key)))
return
defer.returnValue(res.values())
@defer.inlineCallbacks
@log_function
def resolve_state_groups(self, event_ids):
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state_groups = yield self.store.get_state_groups(
event_ids
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)
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))
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state = {}
for group, g_state in state_groups.items():
for s in g_state:
state.setdefault(
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(s.type, s.state_key),
{}
)[s.event_id] = s
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unconflicted_state = {
k: v.values()[0] for k, v in state.items()
if len(v.values()) == 1
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}
conflicted_state = {
k: v.values()
for k, v in state.items()
if len(v.values()) > 1
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}
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
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defer.returnValue((None, new_state))
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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:
return 0
@log_function
def _resolve_state_events(self, events):
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curr_events = events
new_powers = [
self._get_power_level_from_event_state(e, e.user_id)
for e in curr_events
]
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new_powers = [
int(p) if p else 0 for p in new_powers
]
max_power = max(new_powers)
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curr_events = [
z[0] for z in zip(curr_events, new_powers)
if z[1] == max_power
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]
if not curr_events:
raise RuntimeError("Max didn't get a max?")
elif len(curr_events) == 1:
return curr_events[0]
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# TODO: For now, just choose the one with the largest event_id.
return (
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sorted(
curr_events,
key=lambda e: hashlib.sha1(
e.event_id + e.user_id + e.room_id + e.type
).hexdigest()
)[0]
)