/**
* @see Store::getPropertySubjects
*
* @since 2.3
*
* @param DIWikiPage|null $subject
* @param DIProperty $property
* @param RequestOptions $requestOptions = null
*
* @return array
*/
public function getPropertySubjects(DIProperty $property, DataItem $dataItem = null, $requestOptions = null)
{
// The cache is not used for $dataItem === null (means all values for
// the given property are returned)
if ($dataItem === null || !$dataItem instanceof DIWikiPage || !$this->blobStore->canUse() || !$this->canUseValueLookupFeature(SMW_VL_PS)) {
return $this->store->getReader()->getPropertySubjects($property, $dataItem, $requestOptions);
}
// Added as linked list as we keep the container ttl different from
// that of the main container
$sid = $this->getKeyForMainSubject($dataItem, 'ps');
$container = $this->blobStore->read($sid);
$psid = HashBuilder::createHashIdForContent(array($property->getKey(), (array) $requestOptions, self::VERSION), 'ps:');
if ($container->has($psid)) {
return $container->get($psid);
}
$result = $this->store->getReader()->getPropertySubjects($property, $dataItem, $requestOptions);
$container->set($psid, $result);
// We set a short lifetime (5 min) in order to cache repeated requests but
// avoiding a complex invalidation during a subject update otherwise all
// properties of a container would require scanning and removal
$container->setExpiryInSeconds(60 * 5);
$this->blobStore->save($container);
$this->appendToList($sid, $dataItem);
return $result;
}
