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- # Copyright 2015, 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.
- import platform
- import sqlite3
- import struct
- import threading
- from typing import TYPE_CHECKING, Any, List, Mapping, Optional
-
- from synapse.storage.engines import BaseDatabaseEngine
- from synapse.storage.types import Cursor
-
- if TYPE_CHECKING:
- from synapse.storage.database import LoggingDatabaseConnection
-
-
- class Sqlite3Engine(BaseDatabaseEngine[sqlite3.Connection, sqlite3.Cursor]):
- def __init__(self, database_config: Mapping[str, Any]):
- super().__init__(sqlite3, database_config)
-
- database = database_config.get("args", {}).get("database")
- self._is_in_memory = database in (
- None,
- ":memory:",
- )
-
- if platform.python_implementation() == "PyPy":
- # pypy's sqlite3 module doesn't handle bytearrays, convert them
- # back to bytes.
- sqlite3.register_adapter(bytearray, lambda array: bytes(array))
-
- # The current max state_group, or None if we haven't looked
- # in the DB yet.
- self._current_state_group_id = None
- self._current_state_group_id_lock = threading.Lock()
-
- @property
- def single_threaded(self) -> bool:
- return True
-
- @property
- def supports_using_any_list(self) -> bool:
- """Do we support using `a = ANY(?)` and passing a list"""
- return False
-
- @property
- def supports_returning(self) -> bool:
- """Do we support the `RETURNING` clause in insert/update/delete?"""
- return sqlite3.sqlite_version_info >= (3, 35, 0)
-
- def check_database(
- self, db_conn: sqlite3.Connection, allow_outdated_version: bool = False
- ) -> None:
- if not allow_outdated_version:
- # Synapse is untested against older SQLite versions, and we don't want
- # to let users upgrade to a version of Synapse with broken support for their
- # sqlite version, because it risks leaving them with a half-upgraded db.
- if sqlite3.sqlite_version_info < (3, 27, 0):
- raise RuntimeError("Synapse requires sqlite 3.27 or above.")
-
- def check_new_database(self, txn: Cursor) -> None:
- """Gets called when setting up a brand new database. This allows us to
- apply stricter checks on new databases versus existing database.
- """
-
- def convert_param_style(self, sql: str) -> str:
- return sql
-
- def on_new_connection(self, db_conn: "LoggingDatabaseConnection") -> None:
- # We need to import here to avoid an import loop.
- from synapse.storage.prepare_database import prepare_database
-
- if self._is_in_memory:
- # In memory databases need to be rebuilt each time. Ideally we'd
- # reuse the same connection as we do when starting up, but that
- # would involve using adbapi before we have started the reactor.
- prepare_database(db_conn, self, config=None)
-
- db_conn.create_function("rank", 1, _rank)
- db_conn.execute("PRAGMA foreign_keys = ON;")
- db_conn.commit()
-
- def is_deadlock(self, error: Exception) -> bool:
- return False
-
- def is_connection_closed(self, conn: sqlite3.Connection) -> bool:
- return False
-
- def lock_table(self, txn: Cursor, table: str) -> None:
- return
-
- @property
- def server_version(self) -> str:
- """Gets a string giving the server version. For example: '3.22.0'."""
- return "%i.%i.%i" % sqlite3.sqlite_version_info
-
- def in_transaction(self, conn: sqlite3.Connection) -> bool:
- return conn.in_transaction
-
- def attempt_to_set_autocommit(
- self, conn: sqlite3.Connection, autocommit: bool
- ) -> None:
- # Twisted doesn't let us set attributes on the connections, so we can't
- # set the connection to autocommit mode.
- pass
-
- def attempt_to_set_isolation_level(
- self, conn: sqlite3.Connection, isolation_level: Optional[int]
- ) -> None:
- # All transactions are SERIALIZABLE by default in sqlite
- pass
-
- @staticmethod
- def executescript(cursor: sqlite3.Cursor, script: str) -> None:
- """Execute a chunk of SQL containing multiple semicolon-delimited statements.
-
- Python's built-in SQLite driver does not allow you to do this with DBAPI2's
- `execute`:
-
- > execute() will only execute a single SQL statement. If you try to execute more
- > than one statement with it, it will raise a Warning. Use executescript() if
- > you want to execute multiple SQL statements with one call.
-
- Though the docs for `executescript` warn:
-
- > If there is a pending transaction, an implicit COMMIT statement is executed
- > first. No other implicit transaction control is performed; any transaction
- > control must be added to sql_script.
- """
- cursor.executescript(script)
-
-
- # Following functions taken from: https://github.com/coleifer/peewee
-
-
- def _parse_match_info(buf: bytes) -> List[int]:
- bufsize = len(buf)
- return [struct.unpack("@I", buf[i : i + 4])[0] for i in range(0, bufsize, 4)]
-
-
- def _rank(raw_match_info: bytes) -> float:
- """Handle match_info called w/default args 'pcx' - based on the example rank
- function http://sqlite.org/fts3.html#appendix_a
- """
- match_info = _parse_match_info(raw_match_info)
- score = 0.0
- p, c = match_info[:2]
- for phrase_num in range(p):
- phrase_info_idx = 2 + (phrase_num * c * 3)
- for col_num in range(c):
- col_idx = phrase_info_idx + (col_num * 3)
- x1, x2 = match_info[col_idx : col_idx + 2]
- if x1 > 0:
- score += float(x1) / x2
- return score
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