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<?php |
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/** |
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* @link http://www.yiiframework.com/ |
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* @copyright Copyright (c) 2008 Yii Software LLC |
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* @license http://www.yiiframework.com/license/ |
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*/ |
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namespace yii\mutex; |
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use yii\base\Component; |
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/** |
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* The Mutex component allows mutual execution of concurrent processes in order to prevent "race conditions". |
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* |
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* This is achieved by using a "lock" mechanism. Each possibly concurrent thread cooperates by acquiring |
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* a lock before accessing the corresponding data. |
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* |
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* Usage example: |
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* |
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* ``` |
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* if ($mutex->acquire($mutexName)) { |
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* // business logic execution |
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* } else { |
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* // execution is blocked! |
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* } |
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* ``` |
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* |
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* This is a base class, which should be extended in order to implement the actual lock mechanism. |
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* |
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* @author resurtm <[email protected]> |
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* @since 2.0 |
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*/ |
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abstract class Mutex extends Component |
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{ |
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/** |
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* @var bool whether all locks acquired in this process (i.e. local locks) must be released automatically |
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* before finishing script execution. Defaults to true. Setting this property to true means that all locks |
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* acquired in this process must be released (regardless of errors or exceptions). |
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*/ |
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public $autoRelease = true; |
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/** |
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* @var string[] names of the locks acquired by the current PHP process. |
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*/ |
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private $_locks = []; |
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/** |
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* Initializes the Mutex component. |
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*/ |
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public function init() |
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{ |
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if ($this->autoRelease) { |
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$locks = &$this->_locks; |
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register_shutdown_function(function () use (&$locks) { |
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foreach ($locks as $lock) { |
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$this->release($lock); |
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} |
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}); |
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} |
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} |
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/** |
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* Acquires a lock by name. |
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* @param string $name of the lock to be acquired. Must be unique. |
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* @param int $timeout time (in seconds) to wait for lock to be released. Defaults to zero meaning that method will return |
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* false immediately in case lock was already acquired. |
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* @return bool lock acquiring result. |
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*/ |
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public function acquire($name, $timeout = 0) |
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{ |
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if (!in_array($name, $this->_locks, true) && $this->acquireLock($name, $timeout)) { |
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$this->_locks[] = $name; |
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return true; |
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} |
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return false; |
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} |
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/** |
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* Releases acquired lock. This method will return false in case the lock was not found. |
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* @param string $name of the lock to be released. This lock must already exist. |
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* @return bool lock release result: false in case named lock was not found.. |
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*/ |
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public function release($name) |
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{ |
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if ($this->releaseLock($name)) { |
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$index = array_search($name, $this->_locks); |
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if ($index !== false) { |
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unset($this->_locks[$index]); |
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} |
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return true; |
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} |
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return false; |
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} |
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/** |
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* Checks if a lock is currently acquired |
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* |
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* @param string $name of the lock to check |
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* @return bool Returns true if currently acquired |
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* @since 2.0.36 |
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*/ |
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public function isAcquired($name) { |
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return in_array($name, $this->_locks, true); |
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} |
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/** |
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* This method should be extended by a concrete Mutex implementations. Acquires lock by name. |
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* @param string $name of the lock to be acquired. |
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* @param int $timeout time (in seconds) to wait for the lock to be released. |
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* @return bool acquiring result. |
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*/ |
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abstract protected function acquireLock($name, $timeout = 0); |
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/** |
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* This method should be extended by a concrete Mutex implementations. Releases lock by given name. |
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* @param string $name of the lock to be released. |
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* @return bool release result. |
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*/ |
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abstract protected function releaseLock($name); |
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} |
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yiisoft /
yii2
