PgsqlMutex.php
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<?php
/**
* @link http://www.yiiframework.com/
* @copyright Copyright (c) 2008 Yii Software LLC
* @license http://www.yiiframework.com/license/
*/
namespace yii\mutex;
use yii\base\InvalidConfigException;
use yii\base\InvalidParamException;
/**
* PgsqlMutex implements mutex "lock" mechanism via PgSQL locks.
*
* Application configuration example:
*
* ```
* [
* 'components' => [
* 'db' => [
* 'class' => 'yii\db\Connection',
* 'dsn' => 'pgsql:host=127.0.0.1;dbname=demo',
* ]
* 'mutex' => [
* 'class' => 'yii\mutex\PgsqlMutex',
* ],
* ],
* ]
* ```
*
* @see Mutex
*
* @author nineinchnick <janek.jan@gmail.com>
* @since 2.0.8
*/
class PgsqlMutex extends DbMutex
{
/**
* Initializes PgSQL specific mutex component implementation.
* @throws InvalidConfigException if [[db]] is not PgSQL connection.
*/
public function init()
{
parent::init();
if ($this->db->driverName !== 'pgsql') {
throw new InvalidConfigException('In order to use PgsqlMutex connection must be configured to use PgSQL database.');
}
}
/**
* Converts a string into two 16 bit integer keys using the SHA1 hash function.
* @param string $name
* @return array contains two 16 bit integer keys
*/
private function getKeysFromName($name)
{
return array_values(unpack('n2', sha1($name, true)));
}
/**
* Acquires lock by given name.
* @param string $name of the lock to be acquired.
* @param int $timeout to wait for lock to become released.
* @return bool acquiring result.
* @see http://www.postgresql.org/docs/9.0/static/functions-admin.html
*/
protected function acquireLock($name, $timeout = 0)
{
if ($timeout !== 0) {
throw new InvalidParamException('PgsqlMutex does not support timeout.');
}
list($key1, $key2) = $this->getKeysFromName($name);
return (bool) $this->db
->createCommand('SELECT pg_try_advisory_lock(:key1, :key2)', [':key1' => $key1, ':key2' => $key2])
->queryScalar();
}
/**
* Releases lock by given name.
* @param string $name of the lock to be released.
* @return bool release result.
* @see http://www.postgresql.org/docs/9.0/static/functions-admin.html
*/
protected function releaseLock($name)
{
list($key1, $key2) = $this->getKeysFromName($name);
return (bool) $this->db
->createCommand('SELECT pg_advisory_unlock(:key1, :key2)', [':key1' => $key1, ':key2' => $key2])
->queryScalar();
}
}