<?php
/*
* This file is part of the Symfony package.
*
* (c) Fabien Potencier <fabien@symfony.com>
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/
namespace Symfony\Component\Lock;
use Psr\Log\LoggerAwareInterface;
use Psr\Log\LoggerAwareTrait;
use Psr\Log\NullLogger;
use Symfony\Component\Lock\Exception\InvalidArgumentException;
use Symfony\Component\Lock\Exception\LockAcquiringException;
use Symfony\Component\Lock\Exception\LockConflictedException;
use Symfony\Component\Lock\Exception\LockExpiredException;
use Symfony\Component\Lock\Exception\LockReleasingException;
/**
* Lock is the default implementation of the LockInterface.
*
* @author Jérémy Derussé <jeremy@derusse.com>
*/
final class Lock implements SharedLockInterface, LoggerAwareInterface
{
use LoggerAwareTrait;
private $store;
private $key;
private $ttl;
private $autoRelease;
private $dirty = false;
/**
* @param float|null $ttl Maximum expected lock duration in seconds
* @param bool $autoRelease Whether to automatically release the lock or not when the lock instance is destroyed
*/
public function __construct(Key $key, PersistingStoreInterface $store, ?float $ttl = null, bool $autoRelease = true)
{
$this->store = $store;
$this->key = $key;
$this->ttl = $ttl;
$this->autoRelease = $autoRelease;
$this->logger = new NullLogger();
}
public function __sleep(): array
{
throw new \BadMethodCallException('Cannot serialize '.__CLASS__);
}
public function __wakeup()
{
throw new \BadMethodCallException('Cannot unserialize '.__CLASS__);
}
/**
* Automatically releases the underlying lock when the object is destructed.
*/
public function __destruct()
{
if (!$this->autoRelease || !$this->dirty || !$this->isAcquired()) {
return;
}
$this->release();
}
/**
* {@inheritdoc}
*/
public function acquire(bool $blocking = false): bool
{
$this->key->resetLifetime();
try {
if ($blocking) {
if (!$this->store instanceof BlockingStoreInterface) {
while (true) {
try {
$this->store->save($this->key);
break;
} catch (LockConflictedException $e) {
usleep((100 + random_int(-10, 10)) * 1000);
}
}
} else {
$this->store->waitAndSave($this->key);
}
} else {
$this->store->save($this->key);
}
$this->dirty = true;
$this->logger->debug('Successfully acquired the "{resource}" lock.', ['resource' => $this->key]);
if ($this->ttl) {
$this->refresh();
}
if ($this->key->isExpired()) {
try {
$this->release();
} catch (\Exception $e) {
// swallow exception to not hide the original issue
}
throw new LockExpiredException(sprintf('Failed to store the "%s" lock.', $this->key));
}
return true;
} catch (LockConflictedException $e) {
$this->dirty = false;
$this->logger->info('Failed to acquire the "{resource}" lock. Someone else already acquired the lock.', ['resource' => $this->key]);
if ($blocking) {
throw $e;
}
return false;
} catch (\Exception $e) {
$this->logger->notice('Failed to acquire the "{resource}" lock.', ['resource' => $this->key, 'exception' => $e]);
throw new LockAcquiringException(sprintf('Failed to acquire the "%s" lock.', $this->key), 0, $e);
}
}
/**
* {@inheritdoc}
*/
public function acquireRead(bool $blocking = false): bool
{
$this->key->resetLifetime();
try {
if (!$this->store instanceof SharedLockStoreInterface) {
$this->logger->debug('Store does not support ReadLocks, fallback to WriteLock.', ['resource' => $this->key]);
return $this->acquire($blocking);
}
if ($blocking) {
if (!$this->store instanceof BlockingSharedLockStoreInterface) {
while (true) {
try {
$this->store->saveRead($this->key);
break;
} catch (LockConflictedException $e) {
usleep((100 + random_int(-10, 10)) * 1000);
}
}
} else {
$this->store->waitAndSaveRead($this->key);
}
} else {
$this->store->saveRead($this->key);
}
$this->dirty = true;
$this->logger->debug('Successfully acquired the "{resource}" lock for reading.', ['resource' => $this->key]);
if ($this->ttl) {
$this->refresh();
}
if ($this->key->isExpired()) {
try {
$this->release();
} catch (\Exception $e) {
// swallow exception to not hide the original issue
}
throw new LockExpiredException(sprintf('Failed to store the "%s" lock.', $this->key));
}
return true;
} catch (LockConflictedException $e) {
$this->dirty = false;
$this->logger->info('Failed to acquire the "{resource}" lock. Someone else already acquired the lock.', ['resource' => $this->key]);
if ($blocking) {
throw $e;
}
return false;
} catch (\Exception $e) {
$this->logger->notice('Failed to acquire the "{resource}" lock.', ['resource' => $this->key, 'exception' => $e]);
throw new LockAcquiringException(sprintf('Failed to acquire the "%s" lock.', $this->key), 0, $e);
}
}
/**
* {@inheritdoc}
*/
public function refresh(?float $ttl = null)
{
if (null === $ttl) {
$ttl = $this->ttl;
}
if (!$ttl) {
throw new InvalidArgumentException('You have to define an expiration duration.');
}
try {
$this->key->resetLifetime();
$this->store->putOffExpiration($this->key, $ttl);
$this->dirty = true;
if ($this->key->isExpired()) {
try {
$this->release();
} catch (\Exception $e) {
// swallow exception to not hide the original issue
}
throw new LockExpiredException(sprintf('Failed to put off the expiration of the "%s" lock within the specified time.', $this->key));
}
$this->logger->debug('Expiration defined for "{resource}" lock for "{ttl}" seconds.', ['resource' => $this->key, 'ttl' => $ttl]);
} catch (LockConflictedException $e) {
$this->dirty = false;
$this->logger->notice('Failed to define an expiration for the "{resource}" lock, someone else acquired the lock.', ['resource' => $this->key]);
throw $e;
} catch (\Exception $e) {
$this->logger->notice('Failed to define an expiration for the "{resource}" lock.', ['resource' => $this->key, 'exception' => $e]);
throw new LockAcquiringException(sprintf('Failed to define an expiration for the "%s" lock.', $this->key), 0, $e);
}
}
/**
* {@inheritdoc}
*/
public function isAcquired(): bool
{
return $this->dirty = $this->store->exists($this->key);
}
/**
* {@inheritdoc}
*/
public function release()
{
try {
try {
$this->store->delete($this->key);
$this->dirty = false;
} catch (LockReleasingException $e) {
throw $e;
} catch (\Exception $e) {
throw new LockReleasingException(sprintf('Failed to release the "%s" lock.', $this->key), 0, $e);
}
if ($this->store->exists($this->key)) {
throw new LockReleasingException(sprintf('Failed to release the "%s" lock, the resource is still locked.', $this->key));
}
} catch (LockReleasingException $e) {
$this->logger->notice('Failed to release the "{resource}" lock.', ['resource' => $this->key]);
throw $e;
}
}
/**
* {@inheritdoc}
*/
public function isExpired(): bool
{
return $this->key->isExpired();
}
/**
* {@inheritdoc}
*/
public function getRemainingLifetime(): ?float
{
return $this->key->getRemainingLifetime();
}
}