Mutex extension docblocks and several minor fixes.

extensions/mutex/Mutex.php

 <?php
+/**
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright (c) 2008 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
 
 namespace yii\mutex;
 
 use Yii;
 use yii\base\Component;
 
+/**
+ * @author resurtm <resurtm@gmail.com>
+ * @since 2.0
+ */
 abstract class Mutex extends Component
 {
+	/**
+	 * @var boolean whether all locks acquired in this process (i.e. local locks) must be released automagically
+	 * before finishing script execution. Defaults to true. Setting this property to true
+	 */
 	public $autoRelease = true;
-
+	/**
+	 * @var string[] names of the locks acquired in the current PHP process.
+	 */
 	private $_locks = array();
 
 
+	/**
+	 * Initializes the mutex component.
+	 */
 	public function init()
 	{
 		if ($this->autoRelease) {
@@ -20,7 +38,7 @@ abstract class Mutex extends Component
 	}
 
 	/**
-	 * NEVER CALL THIS METHOD UNDER ANY CIRCUMSTANCES
+	 * Never call this method directly under any circumstances. This method is intended for internal use only.
 	 */
 	public function shutdownFunction()
 	{
@@ -29,6 +47,12 @@ abstract class Mutex extends Component
 		}
 	}
 
+	/**
+	 * @param string $name of the lock to be acquired. Must be unique.
+	 * @param integer $timeout to wait for lock to be released. Defaults to zero meaning that method will return
+	 * false immediately in case lock was already acquired.
+	 * @return boolean lock acquiring result.
+	 */
 	public function acquireLock($name, $timeout = 0)
 	{
 		if ($this->acquire($name, $timeout)) {
@@ -39,6 +63,11 @@ abstract class Mutex extends Component
 		}
 	}
 
+	/**
+	 * Release acquired lock.
+	 * @param string $name of the lock to be released. This lock must be already created.
+	 * @return boolean lock release result.
+	 */
 	public function releaseLock($name)
 	{
 		if ($this->release($name)) {
@@ -49,6 +78,12 @@ abstract class Mutex extends Component
 		}
 	}
 
+	/**
+	 * Checks whether named lock was already opened.
+	 * @param string $name of the lock to be checked. This lock must be already created.
+	 * @return boolean|null whether named lock was already opened. Returns `null` value in case concrete
+	 * mutex implementation does not support this operation.
+	 */
 	public function getIsLockAcquired($name)
 	{
 		if (in_array($name, $this->_locks)) {
@@ -58,19 +93,48 @@ abstract class Mutex extends Component
 		}
 	}
 
+	/**
+	 * Checks whether given lock is local. In other words local lock means that it was opened in the current
+	 * PHP process.
+	 * @param string $name of the lock to be checked. This lock must be already created.
+	 * @return boolean whether named lock was locally acquired.
+	 */
 	public function getIsLockLocal($name)
 	{
 		return in_array($name, $this->_locks);
 	}
 
+	/**
+	 * 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 $timeout to wait for lock to become released.
+	 * @return boolean acquiring result.
+	 */
 	abstract protected function acquire($name, $timeout = 0);
 
+	/**
+	 * This method should be extended by concrete mutex implementations. Releases lock by given name.
+	 * @param string $name of the lock to be released.
+	 * @return boolean release result.
+	 */
 	abstract protected function release($name);
 
+	/**
+	 * This method may optionally be extended by concrete mutex implementations. Checks whether lock has been
+	 * already acquired by given name.
+	 * @param string $name of the lock to be released.
+	 * @return null|boolean whether lock has been already acquired. Returns `null` in case this feature
+	 * is not supported by concrete mutex implementation.
+	 */
 	protected function getIsAcquired($name)
 	{
 		return null;
 	}
 
+	/**
+	 * This method should be extended by concrete mutex implementations. Returns whether current mutex
+	 * implementation can be used in a distributed environment.
+	 * @return boolean whether current mutex implementation can be used in a distributed environment.
+	 */
 	abstract public function getIsDistributed();
 }

extensions/mutex/db/Mutex.php

 <?php
+/**
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright (c) 2008 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
 
 namespace yii\mutex\db;
 
@@ -6,22 +11,39 @@ use Yii;
 use yii\db\Connection;
 use yii\base\InvalidConfigException;
 
+/**
+ * @author resurtm <resurtm@gmail.com>
+ * @since 2.0
+ */
 abstract class Mutex extends \yii\mutex\Mutex
 {
 	/**
-	 * @var string|Connection
+	 * @var Connection|string the DB connection object or the application component ID of the DB connection.
+	 * After the Mutex object is created, if you want to change this property, you should only assign
+	 * it with a DB connection object.
 	 */
 	public $db = 'db';
 
+	/**
+	 * Initializes generic database table based mutex implementation.
+	 * @throws InvalidConfigException if [[db]] is invalid.
+	 */
 	public function init()
 	{
 		parent::init();
-		$this->db = Yii::$app->getComponent($this->db);
+		if (is_string($this->db)) {
+			$this->db = Yii::$app->getComponent($this->db);
+		}
 		if (!$this->db instanceof Connection) {
-			throw new InvalidConfigException('');
+			throw new InvalidConfigException('Mutex::db must be either a DB connection instance or the application component ID of a DB connection.');
 		}
 	}
 
+	/**
+	 * This method should be extended by concrete mutex implementations. Returns whether current mutex
+	 * implementation can be used in a distributed environment.
+	 * @return boolean whether current mutex implementation can be used in a distributed environment.
+	 */
 	public function getIsDistributed()
 	{
 		return true;

extensions/mutex/db/mssql/Mutex.php

 <?php
+/**
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright (c) 2008 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
 
 namespace yii\mutex\db\mssql;
 
 use Yii;
 use yii\base\InvalidConfigException;
 
+/**
+ * @author resurtm <resurtm@gmail.com>
+ * @since 2.0
+ */
 class Mutex extends \yii\mutex\db\Mutex
 {
+	/**
+	 * Initializes Microsoft SQL Server specific mutex component implementation.
+	 * @throws InvalidConfigException if [[db]] is not Microsoft SQL Server connection.
+	 */
 	public function init()
 	{
 		parent::init();
@@ -16,13 +29,28 @@ class Mutex extends \yii\mutex\db\Mutex
 		}
 	}
 
+	/**
+	 * 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 $timeout to wait for lock to become released.
+	 * @return boolean acquiring result.
+	 * @throws \BadMethodCallException
+	 * @see http://msdn.microsoft.com/en-us/library/ms189823.aspx
+	 */
 	protected function acquire($name, $timeout = 0)
 	{
-		// http://msdn.microsoft.com/en-us/library/ms189823.aspx
+		throw new \BadMethodCallException('Not implemented yet.');
 	}
 
+	/**
+	 * This method should be extended by concrete mutex implementations. Releases lock by given name.
+	 * @param string $name of the lock to be released.
+	 * @return boolean release result.
+	 * @throws \BadMethodCallException
+	 * @see http://msdn.microsoft.com/en-us/library/ms178602.aspx
+	 */
 	protected function release($name)
 	{
-		// http://msdn.microsoft.com/en-us/library/ms178602.aspx
+		throw new \BadMethodCallException('Not implemented yet.');
 	}
 }

extensions/mutex/db/mysql/Mutex.php

 <?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();
@@ -15,6 +28,13 @@ class Mutex extends \yii\mutex\db\Mutex
 		}
 	}
 
+	/**
+	 * 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
@@ -22,6 +42,12 @@ class Mutex extends \yii\mutex\db\Mutex
 			->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
@@ -29,6 +55,14 @@ class Mutex extends \yii\mutex\db\Mutex
 			->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

extensions/mutex/unix/Mutex.php

 <?php
+/**
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright (c) 2008 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
 
 namespace yii\mutex\unix;
 
 use Yii;
 use yii\base\InvalidConfigException;
 
+/**
+ * @author resurtm <resurtm@gmail.com>
+ * @since 2.0
+ */
 class Mutex extends \yii\mutex\Mutex
 {
+	/**
+	 * @var resource[] stores all opened lock files. Keys are lock names and values are file handles.
+	 */
 	private $_files = array();
 
 
+	/**
+	 * Initializes mutex component implementation dedicated for UNIX, GNU/Linux, Mac OS X, and other UNIX-like
+	 * operating systems.
+	 * @throws InvalidConfigException
+	 */
 	public function init()
 	{
 		if (stripos(php_uname('s'), 'win') === 0) {
@@ -17,6 +34,12 @@ class Mutex extends \yii\mutex\Mutex
 		}
 	}
 
+	/**
+	 * 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 $timeout to wait for lock to become released.
+	 * @return boolean acquiring result.
+	 */
 	protected function acquire($name, $timeout = 0)
 	{
 		$file = fopen(Yii::$app->getRuntimePath() . '/mutex.' . md5($name) . '.lock', 'w+');
@@ -36,6 +59,11 @@ class Mutex extends \yii\mutex\Mutex
 		return true;
 	}
 
+	/**
+	 * This method should be extended by concrete mutex implementations. Releases lock by given name.
+	 * @param string $name of the lock to be released.
+	 * @return boolean release result.
+	 */
 	protected function release($name)
 	{
 		if (!isset($this->_files[$name]) || !flock($this->_files[$name], LOCK_UN)) {
@@ -47,11 +75,23 @@ class Mutex extends \yii\mutex\Mutex
 		}
 	}
 
+	/**
+	 * This method may optionally be extended by concrete mutex implementations. Checks whether lock has been
+	 * already acquired by given name.
+	 * @param string $name of the lock to be released.
+	 * @return null|boolean whether lock has been already acquired. Returns `null` in case this feature
+	 * is not supported by concrete mutex implementation.
+	 */
 	protected function getIsAcquired($name)
 	{
 		return false;
 	}
 
+	/**
+	 * This method should be extended by concrete mutex implementations. Returns whether current mutex
+	 * implementation can be used in a distributed environment.
+	 * @return boolean whether current mutex implementation can be used in a distributed environment.
+	 */
 	public function getIsDistributed()
 	{
 		return false;