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72 lines
1.7 KiB
PHP
72 lines
1.7 KiB
PHP
<?php
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namespace Icicle\Concurrent\Sync;
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use Icicle\Concurrent\Exception\LockAlreadyReleasedError;
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/**
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* A handle on an acquired lock from a synchronization object.
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*
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* This object is not thread-safe; after acquiring a lock from a mutex or
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* semaphore, the lock should reside in the same thread or process until it is
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* released.
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*/
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class Lock
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{
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/**
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* @var callable The function to be called on release.
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*/
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private $releaser;
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/**
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* @var bool Indicates if the lock has been released.
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*/
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private $released = false;
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/**
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* Creates a new lock permit object.
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*
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* @param callable<Lock> $releaser A function to be called upon release.
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*/
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public function __construct(callable $releaser)
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{
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$this->releaser = $releaser;
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}
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/**
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* Checks if the lock has already been released.
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*
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* @return bool True if the lock has already been released, otherwise false.
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*/
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public function isReleased(): bool
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{
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return $this->released;
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}
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/**
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* Releases the lock.
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*
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* @throws LockAlreadyReleasedError If the lock was already released.
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*/
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public function release()
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{
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if ($this->released) {
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throw new LockAlreadyReleasedError('The lock has already been released!');
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}
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// Invoke the releaser function given to us by the synchronization source
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// to release the lock.
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($this->releaser)($this);
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$this->released = true;
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}
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/**
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* Releases the lock when there are no more references to it.
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*/
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public function __destruct()
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{
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if (!$this->released) {
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$this->release();
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}
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}
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}
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