131 lines
4.2 KiB
Python
131 lines
4.2 KiB
Python
# -*- coding: utf-8 -*-
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# Copyright 2014, 2015 OpenMarket Ltd
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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from ._base import SQLBaseStore
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from synapse.util.stringutils import random_string
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import logging
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logger = logging.getLogger(__name__)
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class StateStore(SQLBaseStore):
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""" Keeps track of the state at a given event.
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This is done by the concept of `state groups`. Every event is a assigned
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a state group (identified by an arbitrary string), which references a
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collection of state events. The current state of an event is then the
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collection of state events referenced by the event's state group.
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Hence, every change in the current state causes a new state group to be
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generated. However, if no change happens (e.g., if we get a message event
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with only one parent it inherits the state group from its parent.)
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There are three tables:
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* `state_groups`: Stores group name, first event with in the group and
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room id.
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* `event_to_state_groups`: Maps events to state groups.
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* `state_groups_state`: Maps state group to state events.
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"""
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def get_state_groups(self, event_ids):
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""" Get the state groups for the given list of event_ids
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The return value is a dict mapping group names to lists of events.
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"""
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def f(txn):
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groups = set()
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for event_id in event_ids:
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group = self._simple_select_one_onecol_txn(
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txn,
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table="event_to_state_groups",
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keyvalues={"event_id": event_id},
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retcol="state_group",
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allow_none=True,
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)
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if group:
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groups.add(group)
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res = {}
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for group in groups:
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state_ids = self._simple_select_onecol_txn(
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txn,
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table="state_groups_state",
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keyvalues={"state_group": group},
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retcol="event_id",
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)
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state = self._get_events_txn(txn, state_ids)
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res[group] = state
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return res
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return self.runInteraction(
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"get_state_groups",
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f,
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)
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def _store_state_groups_txn(self, txn, event, context):
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if context.current_state is None:
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return
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state_events = dict(context.current_state)
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if event.is_state():
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state_events[(event.type, event.state_key)] = event
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state_group = context.state_group
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if not state_group:
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group = _make_group_id(self._clock)
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state_group = self._simple_insert_txn(
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txn,
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table="state_groups",
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values={
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"id": group,
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"room_id": event.room_id,
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"event_id": event.event_id,
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},
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)
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for state in state_events.values():
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self._simple_insert_txn(
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txn,
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table="state_groups_state",
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values={
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"state_group": state_group,
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"room_id": state.room_id,
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"type": state.type,
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"state_key": state.state_key,
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"event_id": state.event_id,
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},
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)
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self._simple_insert_txn(
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txn,
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table="event_to_state_groups",
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values={
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"state_group": state_group,
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"event_id": event.event_id,
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},
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or_replace=True,
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)
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def _make_group_id(clock):
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return str(int(clock.time_msec())) + random_string(5)
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