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<?php
namespace Drupal\Core\Cache;
use Drupal\Core\PhpStorage\PhpStorageFactory;
use Drupal\Component\Utility\Crypt;
/**
* Defines a PHP cache implementation.
*
* Stores cache items in a PHP file using a storage that implements
* Drupal\Component\PhpStorage\PhpStorageInterface.
*
* This is fast because of PHP's opcode caching mechanism. Once a file's
* content is stored in PHP's opcode cache, including it doesn't require
* reading the contents from a filesystem. Instead, PHP will use the already
* compiled opcodes stored in memory.
*
* @ingroup cache
*/
class PhpBackend implements CacheBackendInterface {
/**
* @var string
*/
protected $bin;
/**
* Array to store cache objects.
*/
protected $cache = [];
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/**
* The cache tags checksum provider.
*
* @var \Drupal\Core\Cache\CacheTagsChecksumInterface
*/
protected $checksumProvider;
/**
* Constructs a PhpBackend object.
*
* @param string $bin
* The cache bin for which the object is created.
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* @param \Drupal\Core\Cache\CacheTagsChecksumInterface $checksum_provider
* The cache tags checksum provider.
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public function __construct($bin, CacheTagsChecksumInterface $checksum_provider) {
$this->bin = 'cache_' . $bin;
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$this->checksumProvider = $checksum_provider;
}
/**
* {@inheritdoc}
*/
public function get($cid, $allow_invalid = FALSE) {
return $this->getByHash($this->normalizeCid($cid), $allow_invalid);
}
/**
* Fetch a cache item using a hashed cache ID.
*
* @param string $cidhash
* The hashed version of the original cache ID after being normalized.
* @param bool $allow_invalid
* (optional) If TRUE, a cache item may be returned even if it is expired or
* has been invalidated.
*
* @return bool|mixed
*/
protected function getByHash($cidhash, $allow_invalid = FALSE) {
if ($file = $this->storage()->getFullPath($cidhash)) {
$cache = @include $file;
}
if (isset($cache)) {
return $this->prepareItem($cache, $allow_invalid);
}
return FALSE;
}
/**
* {@inheritdoc}
*/
public function setMultiple(array $items) {
foreach ($items as $cid => $item) {
$this->set($cid, $item['data'], isset($item['expire']) ? $item['expire'] : CacheBackendInterface::CACHE_PERMANENT, isset($item['tags']) ? $item['tags'] : []);
}
}
/**
* {@inheritdoc}
*/
public function getMultiple(&$cids, $allow_invalid = FALSE) {
$ret = [];
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foreach ($cids as $cid) {
if ($item = $this->get($cid, $allow_invalid)) {
$ret[$item->cid] = $item;
}
}
$cids = array_diff($cids, array_keys($ret));
return $ret;
}
/**
* Prepares a cached item.
*
* Checks that items are either permanent or did not expire, and returns data
* as appropriate.
*
* @param object $cache
* An item loaded from cache_get() or cache_get_multiple().
* @param bool $allow_invalid
* If FALSE, the method returns FALSE if the cache item is not valid.
*
* @return mixed
* The item with data as appropriate or FALSE if there is no
* valid item to load.
*/
protected function prepareItem($cache, $allow_invalid) {
if (!isset($cache->data)) {
return FALSE;
}
// Check expire time.
$cache->valid = $cache->expire == Cache::PERMANENT || $cache->expire >= REQUEST_TIME;
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// Check if invalidateTags() has been called with any of the item's tags.
if (!$this->checksumProvider->isValid($cache->checksum, $cache->tags)) {
$cache->valid = FALSE;
}
if (!$allow_invalid && !$cache->valid) {
return FALSE;
}
return $cache;
}
/**
* {@inheritdoc}
*/
public function set($cid, $data, $expire = Cache::PERMANENT, array $tags = []) {
assert('\Drupal\Component\Assertion\Inspector::assertAllStrings($tags)', 'Cache Tags must be strings.');
$item = (object) [
'cid' => $cid,
'data' => $data,
'created' => round(microtime(TRUE), 3),
'expire' => $expire,
'tags' => array_unique($tags),
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'checksum' => $this->checksumProvider->getCurrentChecksum($tags),
];
$this->writeItem($this->normalizeCid($cid), $item);
}
/**
* {@inheritdoc}
*/
public function delete($cid) {
$this->storage()->delete($this->normalizeCid($cid));
}
/**
* {@inheritdoc}
*/
public function deleteMultiple(array $cids) {
foreach ($cids as $cid) {
$this->delete($cid);
}
}
/**
* {@inheritdoc}
*/
public function deleteAll() {
$this->storage()->deleteAll();
}
/**
* {@inheritdoc}
*/
public function invalidate($cid) {
$this->invalidatebyHash($this->normalizeCid($cid));
}
/**
* Invalidate one cache item.
*
* @param string $cidhash
* The hashed version of the original cache ID after being normalized.
*/
protected function invalidatebyHash($cidhash) {
if ($item = $this->getByHash($cidhash)) {
$item->expire = REQUEST_TIME - 1;
$this->writeItem($cidhash, $item);
}
}
/**
* {@inheritdoc}
*/
public function invalidateMultiple(array $cids) {
foreach ($cids as $cid) {
$this->invalidate($cid);
}
}
/**
* {@inheritdoc}
*/
public function invalidateAll() {
foreach ($this->storage()->listAll() as $cidhash) {
$this->invalidatebyHash($cidhash);
}
}
/**
* {@inheritdoc}
*/
public function garbageCollection() {
}
/**
* {@inheritdoc}
*/
public function removeBin() {
$this->cache = [];
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$this->storage()->deleteAll();
}
/**
* Writes a cache item to PhpStorage.
*
* @param string $cidhash
* The hashed version of the original cache ID after being normalized.
* @param \stdClass $item
* The cache item to store.
*/
protected function writeItem($cidhash, \stdClass $item) {
$content = '<?php return unserialize(' . var_export(serialize($item), TRUE) . ');';
$this->storage()->save($cidhash, $content);
}
/**
* Gets the PHP code storage object to use.
*
* @return \Drupal\Component\PhpStorage\PhpStorageInterface
*/
protected function storage() {
if (!isset($this->storage)) {
$this->storage = PhpStorageFactory::get($this->bin);
}
return $this->storage;
}
/**
* Ensures a normalized cache ID.
*
* @param string $cid
* The passed in cache ID.
*
* @return string
* A normalized cache ID.
*/
protected function normalizeCid($cid) {
return Crypt::hashBase64($cid);
}