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#
# This file is licensed under the Affero General Public License (AGPL) version 3.
#
# Copyright (C) 2023 New Vector, Ltd
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as
# published by the Free Software Foundation, either version 3 of the
# License, or (at your option) any later version.
#
# See the GNU Affero General Public License for more details:
# <https://www.gnu.org/licenses/agpl-3.0.html>.
#
# Originally licensed under the Apache License, Version 2.0:
# <http://www.apache.org/licenses/LICENSE-2.0>.
#
# [This file includes modifications made by New Vector Limited]
#
#
import logging
from enum import Enum, auto
from typing import TYPE_CHECKING, Optional
if TYPE_CHECKING:
from synapse.server import HomeServer
logger = logging.getLogger(__name__)
class MatchChange(Enum):
no_change = auto()
now_true = auto()
now_false = auto()
class StateDeltasHandler:
def __init__(self, hs: "HomeServer"):
self.store = hs.get_datastores().main
async def _get_key_change(
self,
prev_event_id: Optional[str],
event_id: Optional[str],
key_name: str,
public_value: str,
) -> MatchChange:
"""Given two events check if the `key_name` field in content changed
from not matching `public_value` to doing so.
For example, check if `history_visibility` (`key_name`) changed from
`shared` to `world_readable` (`public_value`).
"""
prev_event = None
event = None
if prev_event_id:
prev_event = await self.store.get_event(prev_event_id, allow_none=True)
if event_id:
event = await self.store.get_event(event_id, allow_none=True)
if not event and not prev_event:
logger.debug("Neither event exists: %r %r", prev_event_id, event_id)
return MatchChange.no_change
prev_value = None
value = None
if prev_event:
prev_value = prev_event.content.get(key_name)
if event:
value = event.content.get(key_name)
logger.debug("prev_value: %r -> value: %r", prev_value, value)
if value == public_value and prev_value != public_value:
return MatchChange.now_true
elif value != public_value and prev_value == public_value:
return MatchChange.now_false
else:
return MatchChange.no_change
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