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<?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\Cache\Traits;
use Psr\Log\LoggerAwareTrait;
use Symfony\Component\Cache\CacheItem;
/**
* @author Nicolas Grekas <p@tchwork.com>
*
* @internal
*/
trait AbstractTrait
{
use LoggerAwareTrait;
private $namespace;
private $namespaceVersion = '';
private $versioningIsEnabled = false;
private $deferred = [];
/**
* @var int|null The maximum length to enforce for identifiers or null when no limit applies
*/
protected $maxIdLength;
/**
* Fetches several cache items.
*
* @param array $ids The cache identifiers to fetch
*
* @return array|\Traversable The corresponding values found in the cache
*/
abstract protected function doFetch(array $ids);
/**
* Confirms if the cache contains specified cache item.
*
* @param string $id The identifier for which to check existence
*
* @return bool True if item exists in the cache, false otherwise
*/
abstract protected function doHave($id);
/**
* Deletes all items in the pool.
*
* @param string $namespace The prefix used for all identifiers managed by this pool
*
* @return bool True if the pool was successfully cleared, false otherwise
*/
abstract protected function doClear($namespace);
/**
* Removes multiple items from the pool.
*
* @param array $ids An array of identifiers that should be removed from the pool
*
* @return bool True if the items were successfully removed, false otherwise
*/
abstract protected function doDelete(array $ids);
/**
* Persists several cache items immediately.
*
* @param array $values The values to cache, indexed by their cache identifier
* @param int $lifetime The lifetime of the cached values, 0 for persisting until manual cleaning
*
* @return array|bool The identifiers that failed to be cached or a boolean stating if caching succeeded or not
*/
abstract protected function doSave(array $values, $lifetime);
/**
* {@inheritdoc}
*/
public function hasItem($key)
{
$id = $this->getId($key);
if (isset($this->deferred[$key])) {
$this->commit();
}
try {
return $this->doHave($id);
} catch (\Exception $e) {
CacheItem::log($this->logger, 'Failed to check if key "{key}" is cached', ['key' => $key, 'exception' => $e]);
return false;
}
}
/**
* {@inheritdoc}
*/
public function clear()
{
$this->deferred = [];
if ($cleared = $this->versioningIsEnabled) {
$namespaceVersion = substr_replace(base64_encode(pack('V', mt_rand())), ':', 5);
try {
$cleared = $this->doSave(['@'.$this->namespace => $namespaceVersion], 0);
} catch (\Exception $e) {
$cleared = false;
}
if ($cleared = true === $cleared || [] === $cleared) {
$this->namespaceVersion = $namespaceVersion;
}
}
try {
return $this->doClear($this->namespace) || $cleared;
} catch (\Exception $e) {
CacheItem::log($this->logger, 'Failed to clear the cache', ['exception' => $e]);
return false;
}
}
/**
* {@inheritdoc}
*/
public function deleteItem($key)
{
return $this->deleteItems([$key]);
}
/**
* {@inheritdoc}
*/
public function deleteItems(array $keys)
{
$ids = [];
foreach ($keys as $key) {
$ids[$key] = $this->getId($key);
unset($this->deferred[$key]);
}
try {
if ($this->doDelete($ids)) {
return true;
}
} catch (\Exception $e) {
}
$ok = true;
// When bulk-delete failed, retry each item individually
foreach ($ids as $key => $id) {
try {
$e = null;
if ($this->doDelete([$id])) {
continue;
}
} catch (\Exception $e) {
}
CacheItem::log($this->logger, 'Failed to delete key "{key}"', ['key' => $key, 'exception' => $e]);
$ok = false;
}
return $ok;
}
/**
* Enables/disables versioning of items.
*
* When versioning is enabled, clearing the cache is atomic and doesn't require listing existing keys to proceed,
* but old keys may need garbage collection and extra round-trips to the back-end are required.
*
* Calling this method also clears the memoized namespace version and thus forces a resynchonization of it.
*
* @param bool $enable
*
* @return bool the previous state of versioning
*/
public function enableVersioning($enable = true)
{
$wasEnabled = $this->versioningIsEnabled;
$this->versioningIsEnabled = (bool) $enable;
$this->namespaceVersion = '';
return $wasEnabled;
}
/**
* {@inheritdoc}
*/
public function reset()
{
if ($this->deferred) {
$this->commit();
}
$this->namespaceVersion = '';
}
/**
* Like the native unserialize() function but throws an exception if anything goes wrong.
*
* @param string $value
*
* @return mixed
*
* @throws \Exception
*/
protected static function unserialize($value)
{
if ('b:0;' === $value) {
return false;
}
$unserializeCallbackHandler = ini_set('unserialize_callback_func', __CLASS__.'::handleUnserializeCallback');
try {
if (false !== $value = unserialize($value)) {
return $value;
}
throw new \DomainException('Failed to unserialize cached value');
} catch (\Error $e) {
throw new \ErrorException($e->getMessage(), $e->getCode(), E_ERROR, $e->getFile(), $e->getLine());
} finally {
ini_set('unserialize_callback_func', $unserializeCallbackHandler);
}
}
private function getId($key)
{
CacheItem::validateKey($key);
if ($this->versioningIsEnabled && '' === $this->namespaceVersion) {
$this->namespaceVersion = '1:';
try {
foreach ($this->doFetch(['@'.$this->namespace]) as $v) {
$this->namespaceVersion = $v;
}
if ('1:' === $this->namespaceVersion) {
$this->namespaceVersion = substr_replace(base64_encode(pack('V', time())), ':', 5);
$this->doSave(['@'.$this->namespace => $this->namespaceVersion], 0);
}
} catch (\Exception $e) {
}
}
if (null === $this->maxIdLength) {
return $this->namespace.$this->namespaceVersion.$key;
}
if (\strlen($id = $this->namespace.$this->namespaceVersion.$key) > $this->maxIdLength) {
$id = $this->namespace.$this->namespaceVersion.substr_replace(base64_encode(hash('sha256', $key, true)), ':', -(\strlen($this->namespaceVersion) + 22));
}
return $id;
}
/**
* @internal
*/
public static function handleUnserializeCallback($class)
{
throw new \DomainException('Class not found: '.$class);
}
}