69 lines
2.0 KiB
Python
69 lines
2.0 KiB
Python
# -*- coding: utf-8 -*-
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# Copyright 2015, 2016 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 synapse.storage.prepare_database import prepare_database
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import struct
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class Sqlite3Engine(object):
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single_threaded = True
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def __init__(self, database_module):
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self.module = database_module
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def check_database(self, txn):
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pass
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def convert_param_style(self, sql):
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return sql
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def on_new_connection(self, db_conn):
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prepare_database(db_conn, self, config=None)
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db_conn.create_function("rank", 1, _rank)
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def is_deadlock(self, error):
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return False
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def is_connection_closed(self, conn):
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return False
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def lock_table(self, txn, table):
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return
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# Following functions taken from: https://github.com/coleifer/peewee
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def _parse_match_info(buf):
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bufsize = len(buf)
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return [struct.unpack('@I', buf[i:i + 4])[0] for i in range(0, bufsize, 4)]
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def _rank(raw_match_info):
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"""Handle match_info called w/default args 'pcx' - based on the example rank
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function http://sqlite.org/fts3.html#appendix_a
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"""
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match_info = _parse_match_info(raw_match_info)
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score = 0.0
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p, c = match_info[:2]
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for phrase_num in range(p):
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phrase_info_idx = 2 + (phrase_num * c * 3)
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for col_num in range(c):
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col_idx = phrase_info_idx + (col_num * 3)
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x1, x2 = match_info[col_idx:col_idx + 2]
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if x1 > 0:
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score += float(x1) / x2
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return score
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