130 lines
4.1 KiB
PHP
130 lines
4.1 KiB
PHP
<?php
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/**
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* @copyright Copyright (c) 2016, ownCloud, Inc.
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*
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* @author Bart Visscher <bartv@thisnet.nl>
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* @author Joas Schilling <coding@schilljs.com>
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* @author Jonny007-MKD <1-23-4-5@web.de>
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* @author Morris Jobke <hey@morrisjobke.de>
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* @author Robin Appelman <robin@icewind.nl>
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* @author Thomas Müller <thomas.mueller@tmit.eu>
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*
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* @license AGPL-3.0
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*
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* This code is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License, version 3,
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* as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License, version 3,
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* along with this program. If not, see <http://www.gnu.org/licenses/>
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*
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*/
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namespace OC\DB;
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use Doctrine\DBAL\Exception\UniqueConstraintViolationException;
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/**
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* This handles the way we use to write queries, into something that can be
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* handled by the database abstraction layer.
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*/
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class Adapter {
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/**
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* @var \OC\DB\Connection $conn
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*/
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protected $conn;
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public function __construct($conn) {
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$this->conn = $conn;
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}
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/**
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* @param string $table name
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* @return int id of last insert statement
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*/
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public function lastInsertId($table) {
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return $this->conn->realLastInsertId($table);
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}
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/**
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* @param string $statement that needs to be changed so the db can handle it
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* @return string changed statement
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*/
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public function fixupStatement($statement) {
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return $statement;
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}
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/**
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* Create an exclusive read+write lock on a table
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*
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* @param string $tableName
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* @since 9.1.0
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*/
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public function lockTable($tableName) {
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$this->conn->beginTransaction();
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$this->conn->executeUpdate('LOCK TABLE `' .$tableName . '` IN EXCLUSIVE MODE');
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}
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/**
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* Release a previous acquired lock again
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*
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* @since 9.1.0
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*/
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public function unlockTable() {
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$this->conn->commit();
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}
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/**
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* Insert a row if the matching row does not exists. To accomplish proper race condition avoidance
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* it is needed that there is also a unique constraint on the values. Then this method will
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* catch the exception and return 0.
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*
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* @param string $table The table name (will replace *PREFIX* with the actual prefix)
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* @param array $input data that should be inserted into the table (column name => value)
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* @param array|null $compare List of values that should be checked for "if not exists"
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* If this is null or an empty array, all keys of $input will be compared
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* Please note: text fields (clob) must not be used in the compare array
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* @return int number of inserted rows
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* @throws \Doctrine\DBAL\DBALException
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* @deprecated 15.0.0 - use unique index and "try { $db->insert() } catch (UniqueConstraintViolationException $e) {}" instead, because it is more reliable and does not have the risk for deadlocks - see https://github.com/nextcloud/server/pull/12371
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*/
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public function insertIfNotExist($table, $input, array $compare = null) {
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if (empty($compare)) {
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$compare = array_keys($input);
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}
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$query = 'INSERT INTO `' .$table . '` (`'
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. implode('`,`', array_keys($input)) . '`) SELECT '
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. str_repeat('?,', count($input)-1).'? ' // Is there a prettier alternative?
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. 'FROM `' . $table . '` WHERE ';
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$inserts = array_values($input);
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foreach($compare as $key) {
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$query .= '`' . $key . '`';
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if (is_null($input[$key])) {
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$query .= ' IS NULL AND ';
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} else {
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$inserts[] = $input[$key];
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$query .= ' = ? AND ';
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}
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}
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$query = substr($query, 0, -5);
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$query .= ' HAVING COUNT(*) = 0';
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try {
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return $this->conn->executeUpdate($query, $inserts);
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} catch (UniqueConstraintViolationException $e) {
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// if this is thrown then a concurrent insert happened between the insert and the sub-select in the insert, that should have avoided it
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// it's fine to ignore this then
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//
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// more discussions about this can be found at https://github.com/nextcloud/server/pull/12315
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return 0;
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}
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}
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}
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