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<?php |
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declare(strict_types=1); |
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namespace Yiisoft\Mutex; |
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use RuntimeException; |
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use function in_array; |
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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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abstract class Mutex implements MutexInterface |
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{ |
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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 array $locks = []; |
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/** |
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* Mutex constructor. |
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* |
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* @param bool $autoRelease Whether all locks acquired in this process (i.e. local locks) must be released |
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* automatically before finishing script execution. Defaults to true. Setting this property |
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* to true means that all locks acquired in this process must be released (regardless of |
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* errors or exceptions). |
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*/ |
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public function __construct(bool $autoRelease = true) |
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{ |
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if ($autoRelease) { |
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$locks = &$this->locks; |
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register_shutdown_function(function () use (&$locks) { |
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/** |
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* @var string $lock |
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*/ |
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foreach ($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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* |
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* @param string $name 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 |
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* will return false immediately in case lock was already acquired. |
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* |
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* @return MutexLockInterface |
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*/ |
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public function acquire(string $name, int $timeout = 0): MutexLockInterface |
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{ |
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if (!in_array($name, $this->locks, true) && $this->acquireLock($name, $timeout)) { |
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$this->locks[] = $name; |
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return new MutexLock($this, $name); |
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} |
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throw new MutexLockedException(); |
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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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* |
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* @param string $name Name of the lock to be released. This lock must already exist. |
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*/ |
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public function release(string $name): void |
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{ |
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if ($this->releaseLock($name)) { |
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$index = array_search($name, $this->locks, true); |
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3 |
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if ($index !== false) { |
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unset($this->locks[$index]); |
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} |
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return; |
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} |
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throw new RuntimeException(); |
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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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* |
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* @param string $name 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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* |
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* @return bool Acquiring result. |
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*/ |
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abstract protected function acquireLock(string $name, int $timeout = 0): bool; |
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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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* |
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* @param string $name Name of the lock to be released. |
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* |
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* @return bool Release result. |
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*/ |
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abstract protected function releaseLock(string $name): bool; |
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} |
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yiisoft /
mutex
