<?
namespace Bitrix\Main\Composite\Internals;

use Bitrix\Main\Application;
use Bitrix\Main\DB\MysqlCommonConnection;

class Locker
{
	const CONNECTION_NAME = "composite";

	/**
	 * Tries to obtain a lock with a name given by the string $id
	 * Supports only Mysql.
	 *
	 * @param string $id Lock Name.
	 * @return bool Returns true if lock was obtained.
	 */
	public static function lock($id)
	{
		$result = true;
		$connection = static::getConnection();
		if ($connection instanceof MysqlCommonConnection)
		{
			$result = $connection->lock($id);
		}

		return $result;
	}

	/**
	 * Releases the lock named by the string $id
	 * Supports only Mysql
	 *
	 * @param string $id Lock Name.
	 * @return bool Returns true if lock was released.
	 */
	public static function unlock($id)
	{
		$connection = static::getConnection();
		if ($connection instanceof MysqlCommonConnection)
		{
			$connection->unlock($id);
		}

		return true;
	}

	/**
	 * Gets a new connection for the lock mechanism
	 * @return \Bitrix\Main\DB\Connection
	 */
	private static function getConnection()
	{
		$pool = Application::getInstance()->getConnectionPool();
		$connection = $pool->getConnection(static::CONNECTION_NAME);
		if (!$connection)
		{
			$connection = $pool->cloneConnection(
				$pool::DEFAULT_CONNECTION_NAME,
				static::CONNECTION_NAME
			);
		}

		return $connection;
	}

}