friendica-github/tests/Util/Database/ExtendedPDO.php

<?php

namespace Friendica\Test\Util\Database;

use PDO;
use PDOException;

/**
 * This class extends native PDO one but allow nested transactions
 * by using the SQL statements `SAVEPOINT', 'RELEASE SAVEPOINT' AND 'ROLLBACK SAVEPOINT'
 */
class ExtendedPDO extends PDO
{
	/**
	 * @var array Database drivers that support SAVEPOINT * statements.
	 */
	protected static $_supportedDrivers = array("pgsql", "mysql");

	/**
	 * @var int the current transaction depth
	 */
	protected $_transactionDepth = 0;

	/**
	 * @return int
	 */
	public function getTransactionDepth()
	{
		return $this->_transactionDepth;
	}

	/**
	 * Test if database driver support savepoints
	 *
	 * @return bool
	 */
	protected function hasSavepoint()
	{
		return in_array($this->getAttribute(PDO::ATTR_DRIVER_NAME),
			self::$_supportedDrivers);
	}


	/**
	 * Start transaction
	 *
	 * @return bool|void
	 */
	public function beginTransaction()
	{
		if($this->_transactionDepth == 0 || !$this->hasSavepoint()) {
			parent::beginTransaction();
		} else {
			$this->exec("SAVEPOINT LEVEL{$this->_transactionDepth}");
		}

		$this->_transactionDepth++;
	}

	/**
	 * Commit current transaction
	 *
	 * @return bool|void
	 */
	public function commit()
	{
		$this->_transactionDepth--;

		if($this->_transactionDepth == 0 || !$this->hasSavepoint()) {
			parent::commit();
		} else {
			$this->exec("RELEASE SAVEPOINT LEVEL{$this->_transactionDepth}");
		}
	}

	/**
	 * Rollback current transaction,
	 *
	 * @throws PDOException if there is no transaction started
	 * @return bool|void
	 */
	public function rollBack()
	{

		if ($this->_transactionDepth == 0) {
			throw new PDOException('Rollback error : There is no transaction started');
		}

		$this->_transactionDepth--;

		if($this->_transactionDepth == 0 || !$this->hasSavepoint()) {
			parent::rollBack();
		} else {
			$this->exec("ROLLBACK TO SAVEPOINT LEVEL{$this->_transactionDepth}");
		}
	}
}