AdapterMySQL.php

<?php

/**
 * SPDX-FileCopyrightText: 2016-2024 Nextcloud GmbH and Nextcloud contributors
 * SPDX-FileCopyrightText: 2016 ownCloud, Inc.
 * SPDX-License-Identifier: AGPL-3.0-only
 */
namespace OC\DB;

class AdapterMySQL extends Adapter {
	/** @var string */
	protected $collation;

	/**
	 * @param string $tableName
	 */
	public function lockTable($tableName) {
		$this->conn->executeUpdate('LOCK TABLES `' . $tableName . '` WRITE');
	}

	public function unlockTable() {
		$this->conn->executeUpdate('UNLOCK TABLES');
	}

	public function fixupStatement($statement) {
		$statement = str_replace(' ILIKE ', ' COLLATE ' . $this->getCollation() . ' LIKE ', $statement);
		return $statement;
	}

	protected function getCollation(): string {
		if (!$this->collation) {
			$params = $this->conn->getParams();
			$this->collation = $params['collation'] ?? (($params['charset'] ?? 'utf8') . '_general_ci');
		}

		return $this->collation;
	}

	public function insertIgnoreConflict(string $table, array $values, array $hintShardKey = []): int {
		$builder = $this->conn->getQueryBuilder();
		$builder->insert($table);
		foreach ($values as $key => $value) {
			$builder->setValue($key, $builder->createNamedParameter($value));
		}

		if (isset($hintShardKey['column'], $hintShardKey['value'])) {
			$builder->hintShardKey($hintShardKey['column'], $hintShardKey['value'], $hintShardKey['overwrite'] ?? false);
		}

		$builder->ignoreConflictsOnInsert();
		return $builder->executeStatement();
	}

	/**
	 * We can't use ON DUPLICATE KEY UPDATE here because Nextcloud use the CLIENT_FOUND_ROWS flag
	 * With this flag the MySQL returns the number of selected rows
	 * instead of the number of affected/modified rows
	 * It's impossible to change this behaviour at runtime or for a single query
	 * Then, the result is 1 if a row is inserted and also 1 if a row is updated with same or different values
	 *
	 * With INSERT IGNORE, the result is 1 when a row is inserted, 0 otherwise
	 *
	 * Risk: it can also ignore other errors like type mismatch or truncated data…
	 */
	public function getInsertIgnoreSqlTransformer(): callable {
		return fn (string $sql) => preg_replace('/^INSERT/i', 'INSERT IGNORE', $sql);
	}
}