1 files changed, 437 insertions, 0 deletions
diff --git a/www/wiki/extensions/SemanticMediaWiki/src/SQLStore/EntityStore/CachingEntityLookup.php b/www/wiki/extensions/SemanticMediaWiki/src/SQLStore/EntityStore/CachingEntityLookup.php
new file mode 100644
index 00000000..a94e28a8
--- /dev/null
+++ b/www/wiki/extensions/SemanticMediaWiki/src/SQLStore/EntityStore/CachingEntityLookup.php
@@ -0,0 +1,437 @@
+<?php
+
+namespace SMW\SQLStore\EntityStore;
+
+use Onoi\BlobStore\BlobStore;
+use SMW\DIProperty;
+use SMW\DIWikiPage;
+use SMW\EntityLookup;
+use SMW\HashBuilder;
+use SMW\Localizer;
+use SMW\RequestOptions;
+use SMW\SemanticData;
+use SMW\SQLStore\Lookup\RedirectTargetLookup;
+use SMWDataItem as DataItem;
+
+/**
+ * Intermediary (fast) access to serialized blob values to avoid DB access on
+ * objects that are static until it is altered. An intermediary object will
+ * invalidate itself on any delete, update, change, or move operation.
+ *
+ * Each subject (including its subobjects) will be stored as individual blob with
+ * each operation belonging to that subject extending its blob to be able
+ * to discard the entire entity at once.
+ *
+ * Each operation request will either fill the cache or return the result from
+ * the cache until the subject is changed and the whole container is being
+ * flushed.
+ *
+ * The class could be decorator but due to the nature of the current Store design
+ * it is called from within each method. The class is not for public use and it
+ * is expected to be accessed only by a Store operation.
+ *
+ * @license GNU GPL v2+
+ * @since 2.3
+ *
+ * @author mwjames
+ */
+class CachingEntityLookup implements EntityLookup {
+
+	/**
+	 * Update this version number when the serialization format
+	 * changes.
+	 */
+	const VERSION = '1.1';
+
+	/**
+	 * @var EntityLookup
+	 */
+	private $entityLookup;
+
+	/**
+	 * @var RedirectTargetLookup
+	 */
+	private $redirectTargetLookup;
+
+	/**
+	 * @var BlobStore
+	 */
+	private $blobStore;
+
+	/**
+	 * @var integer
+	 */
+	private $lookupFeatures = 0;
+
+	/**
+	 * @since 2.3
+	 *
+	 * @param EntityLookup $entityLookup
+	 * @param RedirectTargetLookup $redirectTargetLookup
+	 * @param BlobStore $blobStore
+	 */
+	public function __construct( EntityLookup $entityLookup, RedirectTargetLookup $redirectTargetLookup, BlobStore $blobStore ) {
+		$this->entityLookup = $entityLookup;
+		$this->redirectTargetLookup = $redirectTargetLookup;
+		$this->blobStore = $blobStore;
+	}
+
+	/**
+	 * @since 2.3
+	 *
+	 * @param integer $lookupFeatures
+	 */
+	public function setLookupFeatures( $lookupFeatures ) {
+		$this->lookupFeatures = $lookupFeatures;
+	}
+
+	/**
+	 * @since 2.3
+	 *
+	 * @param integer $lookupFeatures
+	 *
+	 * @return boolean
+	 */
+	public function isEnabledFeature( $lookupFeatures ) {
+		return $this->lookupFeatures === ( $this->lookupFeatures | $lookupFeatures );
+	}
+
+	/**
+	 * @see EntityLookup::getSemanticData
+	 *
+	 * @since 2.5
+	 *
+	 * {@inheritDoc}
+	 */
+	public function getSemanticData( DIWikiPage $subject, $filter = false ) {
+
+		if ( !$this->blobStore->canUse() || !$this->isEnabledFeature( SMW_VL_SD ) ) {
+			return $this->entityLookup->getSemanticData( $subject, $filter );
+		}
+
+		// Use a separate container otherwise large serializations of subobjects
+		// will decrease performance when combined with other lists
+		$sid = $this->getHashFrom(
+			$subject,
+			$subject->getSubobjectName()
+		);
+
+		$container = $this->blobStore->read( $sid );
+
+		// Make sure that when switching user languages, user labels etc.
+		// are appropriately generated
+		$userLang = Localizer::getInstance()->getUserLanguage()->getCode();
+
+		$sdid = HashBuilder::createFromContent(
+			[
+				(array)$filter,
+				self::VERSION
+			],
+			'sd:'. $userLang . ':'
+		);
+
+		if ( $container->has( $sdid ) ) {
+			return $container->get( $sdid );
+		}
+
+		$semanticData = $this->entityLookup->getSemanticData(
+			$subject,
+			$filter
+		);
+
+		$semanticData->setOption(
+			SemanticData::OPT_LAST_MODIFIED,
+			wfTimestamp( TS_UNIX )
+		);
+
+		$container->set( $sdid, $semanticData );
+
+		$this->blobStore->save(
+			$container
+		);
+
+		$this->appendToList( $sid, $subject );
+
+		return $semanticData;
+	}
+
+	/**
+	 * @see EntityLookup::getProperties
+	 *
+	 * @since 2.5
+	 *
+	 * {@inheritDoc}
+	 */
+	public function getProperties( DIWikiPage $subject, RequestOptions $requestOptions = null ) {
+
+		if ( !$this->blobStore->canUse() || !$this->isEnabledFeature( SMW_VL_PL ) ) {
+			return $this->entityLookup->getProperties( $subject, $requestOptions );
+		}
+
+		$container = $this->blobStore->read(
+			$this->getHashFrom( $subject )
+		);
+
+		$plid = HashBuilder::createFromContent(
+			[
+				$subject->getSubobjectName(),
+				(array)$requestOptions,
+				self::VERSION
+			],
+			'pl:'
+		);
+
+		if ( $container->has( $plid ) ) {
+			return $this->resolveRedirectTargets( $container->get( $plid ) );
+		}
+
+		$result = $this->entityLookup->getProperties(
+			$subject,
+			$requestOptions
+		);
+
+		$container->set( $plid, $result );
+
+		$this->blobStore->save(
+			$container
+		);
+
+		return $result;
+	}
+
+	/**
+	 * @see EntityLookup::getPropertyValues
+	 *
+	 * @since 2.5
+	 *
+	 * {@inheritDoc}
+	 */
+	public function getPropertyValues( DIWikiPage $subject = null, DIProperty $property, RequestOptions $requestOptions = null ) {
+
+		// The cache is not used for $subject === null (means all values for
+		// the given property are returned)
+		if ( $subject === null || !$this->blobStore->canUse() || !$this->isEnabledFeature( SMW_VL_PV ) ) {
+			return $this->entityLookup->getPropertyValues( $subject, $property, $requestOptions );
+		}
+
+		// Too many subobjects in one list can kill the performance therefore split
+		// the container by subobject
+		$sid = $this->getHashFrom(
+			$subject,
+			$subject->getSubobjectName()
+		);
+
+		$container = $this->blobStore->read( $sid );
+
+		$pvid = HashBuilder::createFromContent(
+			[
+				$property->getKey(),
+				$property->isInverse(),
+				(array)$requestOptions,
+				self::VERSION
+			],
+			'pv:'
+		);
+
+		if ( $container->has( $pvid ) ) {
+			return $this->resolveRedirectTargets( $container->get( $pvid ) );
+		}
+
+		$result = $this->entityLookup->getPropertyValues(
+			$subject,
+			$property,
+			$requestOptions
+		);
+
+		// Returns a possible iterator, avoid "Serialization of 'Closure' is not allowed"
+		if ( $result instanceof \Iterator ) {
+			$result = iterator_to_array( $result );
+		}
+
+		$container->set( $pvid, $result );
+
+		$this->blobStore->save(
+			$container
+		);
+
+		$this->appendToList( $sid, $subject );
+
+		return $result;
+	}
+
+	/**
+	 * @see EntityLookup::getPropertySubjects
+	 *
+	 * @since 2.5
+	 *
+	 * {@inheritDoc}
+	 */
+	public function getPropertySubjects( DIProperty $property, DataItem $dataItem = null, RequestOptions $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->isEnabledFeature( SMW_VL_PS ) ) {
+			return $this->entityLookup->getPropertySubjects( $property, $dataItem, $requestOptions );
+		}
+
+		// Added as linked list as we keep the container ttl different from
+		// that of the main container
+		$sid = $this->getHashFrom(
+			$dataItem,
+			'ps'
+		);
+
+		$container = $this->blobStore->read( $sid );
+
+		$psid = HashBuilder::createFromContent(
+			[
+				$property->getKey(),
+				$property->isInverse(),
+				(array)$requestOptions,
+				self::VERSION
+			],
+			'ps:'
+		);
+
+		if ( $container->has( $psid ) ) {
+			return $container->get( $psid );
+		}
+
+		$result = $this->entityLookup->getPropertySubjects(
+			$property,
+			$dataItem,
+			$requestOptions
+		);
+
+		// Returns an iterator, avoid "Serialization of 'Closure' is not allowed"
+		if ( $result instanceof \Iterator ) {
+			$result = iterator_to_array( $result );
+		}
+
+		$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;
+	}
+
+	/**
+	 * @see EntityLookup::getAllPropertySubjects
+	 *
+	 * @since 2.5
+	 *
+	 * {@inheritDoc}
+	 */
+	public function getAllPropertySubjects( DIProperty $property, RequestOptions $requestOptions = null  ) {
+		return $this->entityLookup->getAllPropertySubjects( $property, $requestOptions );
+	}
+
+	/**
+	 * @see EntityLookup::getInProperties
+	 *
+	 * @since 2.5
+	 *
+	 * {@inheritDoc}
+	 */
+	public function getInProperties( DataItem $object, RequestOptions $requestOptions = null ) {
+		return $this->entityLookup->getInProperties( $object, $requestOptions );
+	}
+
+	/**
+	 * Remove a cache item that appears during an alteration action (update,
+	 * change, delete) to ensure that we always have the correct set of matches.
+	 *
+	 * @since 2.3
+	 */
+	public function invalidateCache() {
+
+		$args = func_get_args();
+		$subject = array_shift( $args );
+
+		if ( !$this->blobStore->canUse() || !$subject instanceof DIWikiPage ) {
+			return null;
+		}
+
+		// Remove a redirect target subject directly
+		$redirects = $this->getSemanticData( $subject )->getPropertyValues(
+			new DIProperty( '_REDI' )
+		);
+
+		foreach ( $redirects as $redirectTarget ) {
+			$this->blobStore->delete( $this->getHashFrom(
+				$redirectTarget
+			) );
+		}
+
+		$sid = $this->getHashFrom( $subject );
+
+		// Remove all linked objects
+		$container = $this->blobStore->read( $sid );
+
+		if ( $container->has( 'list' ) ) {
+			foreach ( array_keys( $container->get( 'list' ) ) as $id ) {
+				$this->blobStore->delete( $id );
+			}
+		}
+
+		$this->blobStore->delete( $sid );
+	}
+
+	/**
+	 * Ensures that new redirects are resolved while a value is still kept
+	 * in cache (internally it uses getPropertyValues hence we don't loose
+	 * much as objects are reused during the lookup).
+	 */
+	private function resolveRedirectTargets( array $results ) {
+
+		$dataItems =  [];
+
+		foreach ( $results as $dataItem ) {
+			$dataItems[] = $this->redirectTargetLookup->findRedirectTarget( $dataItem );
+		}
+
+		return $dataItems;
+	}
+
+	/**
+	 * The subobject is attached to a root subject therefore using the root as
+	 * identifier to allow it to be invalidated at once with all other subobjects
+	 * that relate to a subject
+	 */
+	private function getHashFrom( DIWikiPage $subject, $suffix = '' ) {
+		return md5( HashBuilder::createHashIdFromSegments(
+			$subject->getDBkey(),
+			$subject->getNamespace(),
+			$subject->getInterwiki()
+		) . $suffix );
+	}
+
+	private function appendToList( $id, $subject ) {
+
+		// Store the id with the main subject
+		$container = $this->blobStore->read(
+			$this->getHashFrom( $subject )
+		);
+
+		// Use the id as key to avoid unnecessary duplicate entries when
+		// employing append
+		$container->append(
+			'list',
+			[ $id => true ]
+		);
+
+		$this->blobStore->save(
+			$container
+		);
+	}
+
+}