391 lines
13 KiB
Python
391 lines
13 KiB
Python
# -*- coding: utf-8 -*-
|
|
# Copyright 2014, 2015 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 synapse.util.caches.expiringcache import ExpiringCache
|
|
from synapse.api.constants import EventTypes
|
|
from synapse.api.errors import AuthError
|
|
from synapse.api.auth import AuthEventTypes
|
|
from synapse.events.snapshot import EventContext
|
|
|
|
from collections import namedtuple
|
|
|
|
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"))
|
|
|
|
|
|
SIZE_OF_CACHE = 1000
|
|
EVICTION_TIMEOUT_SECONDS = 20
|
|
|
|
|
|
class _StateCacheEntry(object):
|
|
def __init__(self, state, state_group, ts):
|
|
self.state = state
|
|
self.state_group = state_group
|
|
|
|
|
|
class StateHandler(object):
|
|
""" Responsible for doing state conflict resolution.
|
|
"""
|
|
|
|
def __init__(self, hs):
|
|
self.clock = hs.get_clock()
|
|
self.store = hs.get_datastore()
|
|
self.hs = hs
|
|
|
|
# dict of set of event_ids -> _StateCacheEntry.
|
|
self._state_cache = None
|
|
|
|
def start_caching(self):
|
|
logger.debug("start_caching")
|
|
|
|
self._state_cache = ExpiringCache(
|
|
cache_name="state_cache",
|
|
clock=self.clock,
|
|
max_len=SIZE_OF_CACHE,
|
|
expiry_ms=EVICTION_TIMEOUT_SECONDS*1000,
|
|
reset_expiry_on_get=True,
|
|
)
|
|
|
|
self._state_cache.start()
|
|
|
|
@defer.inlineCallbacks
|
|
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 is equivalent to getting the state of an event that were to send
|
|
next before receiving any new events.
|
|
|
|
If `event_type` is specified, then the method returns only the one
|
|
event (or None) with that `event_type` and `state_key`.
|
|
"""
|
|
event_ids = yield self.store.get_latest_event_ids_in_room(room_id)
|
|
|
|
cache = None
|
|
if self._state_cache is not None:
|
|
cache = self._state_cache.get(frozenset(event_ids), None)
|
|
|
|
if cache:
|
|
cache.ts = self.clock.time_msec()
|
|
state = cache.state
|
|
else:
|
|
res = yield self.resolve_state_groups(room_id, event_ids)
|
|
state = res[1]
|
|
|
|
if event_type:
|
|
defer.returnValue(state.get((event_type, state_key)))
|
|
return
|
|
|
|
defer.returnValue(state)
|
|
|
|
@defer.inlineCallbacks
|
|
def compute_event_context(self, event, old_state=None, outlier=False):
|
|
""" Fills out the context with the `current state` of the graph. The
|
|
`current state` here is defined to be the state of the event graph
|
|
just before the event - i.e. it never includes `event`
|
|
|
|
If `event` has `auth_events` then this will also fill out the
|
|
`auth_events` field on `context` from the `current_state`.
|
|
|
|
Args:
|
|
event (EventBase)
|
|
Returns:
|
|
an EventContext
|
|
"""
|
|
yield run_on_reactor()
|
|
|
|
context = EventContext()
|
|
|
|
if outlier:
|
|
# If this is an outlier, then we know it shouldn't have any current
|
|
# state. Certainly store.get_current_state won't return any, and
|
|
# persisting the event won't store the state group.
|
|
if old_state:
|
|
context.current_state = {
|
|
(s.type, s.state_key): s for s in old_state
|
|
}
|
|
else:
|
|
context.current_state = {}
|
|
context.prev_state_events = []
|
|
context.state_group = None
|
|
defer.returnValue(context)
|
|
|
|
if old_state:
|
|
context.current_state = {
|
|
(s.type, s.state_key): s for s in old_state
|
|
}
|
|
context.state_group = None
|
|
|
|
if event.is_state():
|
|
key = (event.type, event.state_key)
|
|
if key in context.current_state:
|
|
replaces = context.current_state[key]
|
|
if replaces.event_id != event.event_id: # Paranoia check
|
|
event.unsigned["replaces_state"] = replaces.event_id
|
|
|
|
context.prev_state_events = []
|
|
defer.returnValue(context)
|
|
|
|
if event.is_state():
|
|
ret = yield self.resolve_state_groups(
|
|
event.room_id, [e for e, _ in event.prev_events],
|
|
event_type=event.type,
|
|
state_key=event.state_key,
|
|
)
|
|
else:
|
|
ret = yield self.resolve_state_groups(
|
|
event.room_id, [e for e, _ in event.prev_events],
|
|
)
|
|
|
|
group, curr_state, prev_state = ret
|
|
|
|
context.current_state = curr_state
|
|
context.state_group = group if not event.is_state() else None
|
|
|
|
if event.is_state():
|
|
key = (event.type, event.state_key)
|
|
if key in context.current_state:
|
|
replaces = context.current_state[key]
|
|
event.unsigned["replaces_state"] = replaces.event_id
|
|
|
|
context.prev_state_events = prev_state
|
|
defer.returnValue(context)
|
|
|
|
@defer.inlineCallbacks
|
|
@log_function
|
|
def resolve_state_groups(self, room_id, event_ids, event_type=None, state_key=""):
|
|
""" Given a list of event_ids this method fetches the state at each
|
|
event, resolves conflicts between them and returns them.
|
|
|
|
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`.
|
|
"""
|
|
logger.debug("resolve_state_groups event_ids %s", event_ids)
|
|
|
|
if self._state_cache is not None:
|
|
cache = self._state_cache.get(frozenset(event_ids), None)
|
|
if cache and cache.state_group:
|
|
cache.ts = self.clock.time_msec()
|
|
prev_state = cache.state.get((event_type, state_key), None)
|
|
if prev_state:
|
|
prev_state = prev_state.event_id
|
|
prev_states = [prev_state]
|
|
else:
|
|
prev_states = []
|
|
defer.returnValue(
|
|
(cache.state_group, cache.state, prev_states)
|
|
)
|
|
|
|
state_groups = yield self.store.get_state_groups(
|
|
room_id, event_ids
|
|
)
|
|
|
|
logger.debug(
|
|
"resolve_state_groups state_groups %s",
|
|
state_groups.keys()
|
|
)
|
|
|
|
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
|
|
}
|
|
prev_state = state.get((event_type, state_key), None)
|
|
if prev_state:
|
|
prev_state = prev_state.event_id
|
|
prev_states = [prev_state]
|
|
else:
|
|
prev_states = []
|
|
|
|
if self._state_cache is not None:
|
|
cache = _StateCacheEntry(
|
|
state=state,
|
|
state_group=name,
|
|
ts=self.clock.time_msec()
|
|
)
|
|
|
|
self._state_cache[frozenset(event_ids)] = cache
|
|
|
|
defer.returnValue((name, state, prev_states))
|
|
|
|
new_state, prev_states = self._resolve_events(
|
|
state_groups.values(), event_type, state_key
|
|
)
|
|
|
|
if self._state_cache is not None:
|
|
cache = _StateCacheEntry(
|
|
state=new_state,
|
|
state_group=None,
|
|
ts=self.clock.time_msec()
|
|
)
|
|
|
|
self._state_cache[frozenset(event_ids)] = cache
|
|
|
|
defer.returnValue((None, new_state, prev_states))
|
|
|
|
def resolve_events(self, state_sets, event):
|
|
if event.is_state():
|
|
return self._resolve_events(
|
|
state_sets, event.type, event.state_key
|
|
)
|
|
else:
|
|
return self._resolve_events(state_sets)
|
|
|
|
def _resolve_events(self, state_sets, event_type=None, state_key=""):
|
|
state = {}
|
|
for st in state_sets:
|
|
for e in st:
|
|
state.setdefault(
|
|
(e.type, e.state_key),
|
|
{}
|
|
)[e.event_id] = e
|
|
|
|
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
|
|
}
|
|
|
|
if event_type:
|
|
prev_states_events = conflicted_state.get(
|
|
(event_type, state_key), []
|
|
)
|
|
prev_states = [s.event_id for s in prev_states_events]
|
|
else:
|
|
prev_states = []
|
|
|
|
auth_events = {
|
|
k: e for k, e in unconflicted_state.items()
|
|
if k[0] in AuthEventTypes
|
|
}
|
|
|
|
try:
|
|
resolved_state = self._resolve_state_events(
|
|
conflicted_state, auth_events
|
|
)
|
|
except:
|
|
logger.exception("Failed to resolve state")
|
|
raise
|
|
|
|
new_state = unconflicted_state
|
|
new_state.update(resolved_state)
|
|
|
|
return new_state, prev_states
|
|
|
|
@log_function
|
|
def _resolve_state_events(self, conflicted_state, auth_events):
|
|
""" This is where we actually decide which of the conflicted state to
|
|
use.
|
|
|
|
We resolve conflicts in the following order:
|
|
1. power levels
|
|
2. memberships
|
|
3. other events.
|
|
"""
|
|
resolved_state = {}
|
|
power_key = (EventTypes.PowerLevels, "")
|
|
if power_key in conflicted_state.items():
|
|
power_levels = conflicted_state[power_key]
|
|
resolved_state[power_key] = self._resolve_auth_events(power_levels)
|
|
|
|
auth_events.update(resolved_state)
|
|
|
|
for key, events in conflicted_state.items():
|
|
if key[0] == EventTypes.JoinRules:
|
|
resolved_state[key] = self._resolve_auth_events(
|
|
events,
|
|
auth_events
|
|
)
|
|
|
|
auth_events.update(resolved_state)
|
|
|
|
for key, events in conflicted_state.items():
|
|
if key[0] == EventTypes.Member:
|
|
resolved_state[key] = self._resolve_auth_events(
|
|
events,
|
|
auth_events
|
|
)
|
|
|
|
auth_events.update(resolved_state)
|
|
|
|
for key, events in conflicted_state.items():
|
|
if key not in resolved_state:
|
|
resolved_state[key] = self._resolve_normal_events(
|
|
events, auth_events
|
|
)
|
|
|
|
return resolved_state
|
|
|
|
def _resolve_auth_events(self, events, auth_events):
|
|
reverse = [i for i in reversed(self._ordered_events(events))]
|
|
|
|
auth_events = dict(auth_events)
|
|
|
|
prev_event = reverse[0]
|
|
for event in reverse[1:]:
|
|
auth_events[(prev_event.type, prev_event.state_key)] = prev_event
|
|
try:
|
|
# FIXME: hs.get_auth() is bad style, but we need to do it to
|
|
# get around circular deps.
|
|
self.hs.get_auth().check(event, auth_events)
|
|
prev_event = event
|
|
except AuthError:
|
|
return prev_event
|
|
|
|
return event
|
|
|
|
def _resolve_normal_events(self, events, auth_events):
|
|
for event in self._ordered_events(events):
|
|
try:
|
|
# FIXME: hs.get_auth() is bad style, but we need to do it to
|
|
# get around circular deps.
|
|
self.hs.get_auth().check(event, auth_events)
|
|
return event
|
|
except AuthError:
|
|
pass
|
|
|
|
# Use the last event (the one with the least depth) if they all fail
|
|
# the auth check.
|
|
return event
|
|
|
|
def _ordered_events(self, events):
|
|
def key_func(e):
|
|
return -int(e.depth), hashlib.sha1(e.event_id).hexdigest()
|
|
|
|
return sorted(events, key=key_func)
|