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