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parallel/lib/Sync/Lock.php
2016-07-20 09:23:50 -05:00

72 lines
1.7 KiB
PHP

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