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- # -*- coding: utf-8 -*-
- # Copyright 2016 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 typing import List, Optional, Tuple
- from synapse.storage.types import Connection
- from synapse.storage.util.id_generators import _load_current_id
- class SlavedIdTracker:
- def __init__(
- self,
- db_conn: Connection,
- table: str,
- column: str,
- extra_tables: Optional[List[Tuple[str, str]]] = None,
- step: int = 1,
- ):
- self.step = step
- self._current = _load_current_id(db_conn, table, column, step)
- if extra_tables:
- for table, column in extra_tables:
- self.advance(None, _load_current_id(db_conn, table, column))
- def advance(self, instance_name: Optional[str], new_id: int):
- self._current = (max if self.step > 0 else min)(self._current, new_id)
- def get_current_token(self) -> int:
- """
- Returns:
- int
- """
- return self._current
- def get_current_token_for_writer(self, instance_name: str) -> int:
- """Returns the position of the given writer.
- For streams with single writers this is equivalent to
- `get_current_token`.
- """
- return self.get_current_token()
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