67 lines
2.2 KiB
Python
67 lines
2.2 KiB
Python
# -*- coding: utf-8 -*-
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# Copyright 2018 New Vector 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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import logging
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logger = logging.getLogger(__name__)
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class StateDeltasHandler:
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def __init__(self, hs):
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self.store = hs.get_datastore()
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async def _get_key_change(self, prev_event_id, event_id, key_name, public_value):
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"""Given two events check if the `key_name` field in content changed
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from not matching `public_value` to doing so.
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For example, check if `history_visibility` (`key_name`) changed from
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`shared` to `world_readable` (`public_value`).
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Returns:
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None if the field in the events either both match `public_value`
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or if neither do, i.e. there has been no change.
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True if it didnt match `public_value` but now does
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False if it did match `public_value` but now doesn't
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"""
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prev_event = None
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event = None
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if prev_event_id:
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prev_event = await self.store.get_event(prev_event_id, allow_none=True)
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if event_id:
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event = await self.store.get_event(event_id, allow_none=True)
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if not event and not prev_event:
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logger.debug("Neither event exists: %r %r", prev_event_id, event_id)
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return None
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prev_value = None
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value = None
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if prev_event:
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prev_value = prev_event.content.get(key_name)
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if event:
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value = event.content.get(key_name)
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logger.debug("prev_value: %r -> value: %r", prev_value, value)
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if value == public_value and prev_value != public_value:
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return True
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elif value != public_value and prev_value == public_value:
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return False
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else:
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return None
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