composer.json file and proper class files location.

extensions/mutex/yii/db/mysql/Mutex.php

@@ -0,0 +1,72 @@
+<?php
+/**
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright (c) 2008 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+
+namespace yii\mutex\db\mysql;
+
+use Yii;
+use yii\base\InvalidConfigException;
+
+/**
+ * @author resurtm <resurtm@gmail.com>
+ * @since 2.0
+ */
+class Mutex extends \yii\mutex\db\Mutex
+{
+	/**
+	 * Initializes MySQL specific mutex component implementation.
+	 * @throws InvalidConfigException if [[db]] is not MySQL connection.
+	 */
+	public function init()
+	{
+		parent::init();
+		if ($this->db->driverName !== 'mysql') {
+			throw new InvalidConfigException('');
+		}
+	}
+
+	/**
+	 * This method should be extended by concrete mutex implementations. Acquires lock by given name.
+	 * @param string $name of the lock to be acquired.
+	 * @param integer $timeout to wait for lock to become released.
+	 * @return boolean acquiring result.
+	 * @see http://dev.mysql.com/doc/refman/5.0/en/miscellaneous-functions.html#function_get-lock
+	 */
+	protected function acquire($name, $timeout = 0)
+	{
+		return (boolean)$this->db
+			->createCommand('SELECT GET_LOCK(:name, :timeout)', array(':name' => $name, ':timeout' => $timeout))
+			->queryScalar();
+	}
+
+	/**
+	 * This method should be extended by concrete mutex implementations. Releases lock by given name.
+	 * @param string $name of the lock to be released.
+	 * @return boolean release result.
+	 * @see http://dev.mysql.com/doc/refman/5.0/en/miscellaneous-functions.html#function_release-lock
+	 */
+	protected function release($name)
+	{
+		return (boolean)$this->db
+			->createCommand('SELECT RELEASE_LOCK(:name)', array(':name' => $name))
+			->queryScalar();
+	}
+
+	/**
+	 * This method may optionally be extended by concrete mutex implementations. Checks whether lock has been
+	 * already acquired by given name.
+	 * @param string $name of the lock to be released.
+	 * @return null|boolean whether lock has been already acquired. Returns `null` in case this feature
+	 * is not supported by concrete mutex implementation.
+	 * @see http://dev.mysql.com/doc/refman/5.0/en/miscellaneous-functions.html#function_is-free-lock
+	 */
+	protected function getIsAcquired($name)
+	{
+		return (boolean)$this->db
+			->createCommand('SELECT IS_FREE_LOCK(:name)', array(':name' => $name))
+			->queryScalar();
+	}
+}