Defines a memory cache implementation.
Stores cache items in memory using a PHP array.
Should be used for unit tests and specialist use-cases only, does not store cached items between requests.
Expanded class hierarchy of MemoryBackend
class MemoryBackend implements CacheBackendInterface {
/**
* Array to store cache objects.
*/
protected $cache = array();
/**
* Constructs a MemoryBackend object.
*
* @param string $bin
* The cache bin for which the object is created.
*/
public function __construct($bin) {
}
/**
* Implements Drupal\Core\Cache\CacheBackendInterface::get().
*/
public function get($cid, $allow_invalid = FALSE) {
if (isset($this->cache[$cid])) {
return $this
->prepareItem($this->cache[$cid], $allow_invalid);
}
else {
return FALSE;
}
}
/**
* Implements Drupal\Core\Cache\CacheBackendInterface::getMultiple().
*/
public function getMultiple(&$cids, $allow_invalid = FALSE) {
$ret = array();
$items = array_intersect_key($this->cache, array_flip($cids));
foreach ($items as $item) {
$item = $this
->prepareItem($item, $allow_invalid);
if ($item) {
$ret[$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 stdClass $cache
* An item loaded from cache_get() or cache_get_multiple().
*
* @return mixed
* The item with data as appropriate or FALSE if there is no
* valid item to load.
*/
protected function prepareItem($cache, $allow_invalid) {
if (!isset($cache->data)) {
return FALSE;
}
// Check expire time.
$cache->valid = $cache->expire == CacheBackendInterface::CACHE_PERMANENT || $cache->expire >= REQUEST_TIME;
if (!$allow_invalid && !$cache->valid) {
return FALSE;
}
return $cache;
}
/**
* Implements Drupal\Core\Cache\CacheBackendInterface::set().
*/
public function set($cid, $data, $expire = CacheBackendInterface::CACHE_PERMANENT, array $tags = array()) {
$this->cache[$cid] = (object) array(
'cid' => $cid,
'data' => $data,
'created' => REQUEST_TIME,
'expire' => $expire,
'tags' => $this
->flattenTags($tags),
);
}
/**
* Implements Drupal\Core\Cache\CacheBackendInterface::delete().
*/
public function delete($cid) {
unset($this->cache[$cid]);
}
/**
* Implements Drupal\Core\Cache\CacheBackendInterface::deleteMultiple().
*/
public function deleteMultiple(array $cids) {
$this->cache = array_diff_key($this->cache, array_flip($cids));
}
/**
* Implements Drupal\Core\Cache\CacheBackendInterface::deleteTags().
*/
public function deleteTags(array $tags) {
$flat_tags = $this
->flattenTags($tags);
foreach ($this->cache as $cid => $item) {
if (array_intersect($flat_tags, $item->tags)) {
unset($this->cache[$cid]);
}
}
}
/**
* Implements Drupal\Core\Cache\CacheBackendInterface::deleteAll().
*/
public function deleteAll() {
$this->cache = array();
}
/**
* Implements Drupal\Core\Cache\CacheBackendInterface::invalidate().
*/
public function invalidate($cid) {
$this->cache[$cid]->expire = REQUEST_TIME - 1;
}
/**
* Implements Drupal\Core\Cache\CacheBackendInterface::invalidateMultiple().
*/
public function invalidateMultiple(array $cids) {
foreach ($cids as $cid) {
$this->cache[$cid]->expire = REQUEST_TIME - 1;
}
}
/**
* Implements Drupal\Core\Cache\CacheBackendInterface::invalidateTags().
*/
public function invalidateTags(array $tags) {
$flat_tags = $this
->flattenTags($tags);
foreach ($this->cache as $cid => $item) {
if (array_intersect($flat_tags, $item->tags)) {
$this->cache[$cid]->expire = REQUEST_TIME - 1;
}
}
}
/**
* Implements Drupal\Core\Cache\CacheBackendInterface::invalidateAll().
*/
public function invalidateAll() {
foreach ($this->cache as $cid => $item) {
$this->cache[$cid]->expire = REQUEST_TIME - 1;
}
}
/**
* 'Flattens' a tags array into an array of strings.
*
* @param array $tags
* Associative array of tags to flatten.
*
* @return array
* An indexed array of strings.
*/
protected function flattenTags(array $tags) {
if (isset($tags[0])) {
return $tags;
}
$flat_tags = array();
foreach ($tags as $namespace => $values) {
if (is_array($values)) {
foreach ($values as $value) {
$flat_tags["{$namespace}:{$value}"] = "{$namespace}:{$value}";
}
}
else {
$flat_tags["{$namespace}:{$values}"] = "{$namespace}:{$values}";
}
}
return $flat_tags;
}
/**
* Implements Drupal\Core\Cache\CacheBackendInterface::isEmpty().
*/
public function isEmpty() {
return empty($this->cache);
}
/**
* Implements Drupal\Core\Cache\CacheBackendInterface::garbageCollection()
*/
public function garbageCollection() {
}
/**
* {@inheritdoc}
*/
public function removeBin() {
}
}