1 files changed, 252 insertions, 0 deletions
diff --git a/www/wiki/extensions/SemanticMediaWiki/src/PropertyChangePropagationNotifier.php b/www/wiki/extensions/SemanticMediaWiki/src/PropertyChangePropagationNotifier.php
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+++ b/www/wiki/extensions/SemanticMediaWiki/src/PropertyChangePropagationNotifier.php
@@ -0,0 +1,252 @@
+<?php
+
+namespace SMW;
+
+use SMW\MediaWiki\Jobs\ChangePropagationDispatchJob;
+use SMWDataItem;
+use SMWDIBlob as DIBlob;
+
+/**
+ * Before a new set of data (type, constraints etc.) is stored about a property
+ * the class tries to compare old and new specifications (values about that property)
+ * and notifies a dispatcher about a change.
+ *
+ * @license GNU GPL v2+
+ * @since 1.9
+ *
+ * @author mwjames
+ * @author Markus Krötzsch
+ */
+class PropertyChangePropagationNotifier {
+
+	/**
+	 * @var Store
+	 */
+	private $store;
+
+	/**
+	 * @var SerializerFactory
+	 */
+	private $serializerFactory;
+
+	/**
+	 * @var array
+	 */
+	private $propertyList = [];
+
+	/**
+	 * @var boolean
+	 */
+	private $hasDiff = false;
+
+	/**
+	 * @var boolean
+	 */
+	private $isTypePropagation = false;
+
+	/**
+	 * @var boolean
+	 */
+	private $isCommandLineMode = false;
+
+	/**
+	 * @since 1.9
+	 *
+	 * @param Store $store
+	 * @param SerializerFactory $serializerFactory
+	 */
+	public function __construct( Store $store, SerializerFactory $serializerFactory ) {
+		$this->store = $store;
+		$this->serializerFactory = $serializerFactory;
+	}
+
+	/**
+	 * @since 2.5
+	 *
+	 * @param array $propertyList
+	 */
+	public function setPropertyList( array $propertyList ) {
+		$this->propertyList = $propertyList;
+	}
+
+	/**
+	 * @see https://www.mediawiki.org/wiki/Manual:$wgCommandLineMode
+	 * Indicates whether MW is running in command-line mode.
+	 *
+	 * @since 3.0
+	 *
+	 * @param boolean $isCommandLineMode
+	 */
+	public function isCommandLineMode( $isCommandLineMode ) {
+		$this->isCommandLineMode = $isCommandLineMode;
+	}
+
+	/**
+	 * @since 1.9
+	 *
+	 * @return boolean
+	 */
+	public function hasDiff() {
+		return $this->hasDiff;
+	}
+
+	/**
+	 * @since 2.5
+	 *
+	 * @param DIWikiPage $subject
+	 */
+	public function notify( DIWikiPage $subject ) {
+
+		$namespace = $subject->getNamespace();
+
+		if ( !$this->hasDiff() || ( $namespace !== SMW_NS_PROPERTY && $namespace !== NS_CATEGORY ) ) {
+			return false;
+		}
+
+		$params = [];
+
+		if ( $this->isTypePropagation ) {
+			$params['isTypePropagation'] = true;
+		}
+
+		return ChangePropagationDispatchJob::planAsJob( $subject, $params );
+	}
+
+	/**
+	 * Compare and detect differences between the invoked semantic data
+	 * and the current stored data
+	 *
+	 * @note Compare on extra properties from `smwgChangePropagationWatchlist`
+	 * (e.g '_PLIST') to find a possible specification change
+	 *
+	 * @since 1.9
+	 */
+	public function checkAndNotify( SemanticData &$semanticData ) {
+
+		$namespace = $semanticData->getSubject()->getNamespace();
+
+		if ( $namespace !== SMW_NS_PROPERTY && $namespace !== NS_CATEGORY ) {
+			return;
+		}
+
+		$this->hasDiff = false;
+
+		// Check the type first
+		$propertyList = array_merge(
+			[
+				'_TYPE',
+				'_CONV',
+				'_UNIT',
+				'_REDI'
+			],
+			$this->propertyList
+		);
+
+		foreach ( $propertyList as $key ) {
+
+			// No need to keep comparing once a diff has been
+			// detected
+			if ( $this->hasDiff() ) {
+				break;
+			}
+
+			$this->doCompare( $semanticData, $key );
+		}
+
+		$this->doNotifyAndPostpone( $semanticData );
+	}
+
+	private function doCompare( $semanticData, $key ) {
+
+		$property = new DIProperty( $key );
+
+		$newValues = $semanticData->getPropertyValues( $property );
+
+		$oldValues = $this->store->getPropertyValues(
+			$semanticData->getSubject(),
+			$property
+		);
+
+		$this->setDiff( !$this->isEqual( $oldValues, $newValues ), $key );
+	}
+
+	private function setDiff( $hasDiff = true, $key ) {
+
+		if ( !$hasDiff || $this->hasDiff ) {
+			return;
+		}
+
+		$this->hasDiff = true;
+		$this->isTypePropagation = $key === '_TYPE';
+	}
+
+	/**
+	 * Helper function that compares two arrays of data values to check whether
+	 * they contain the same content. Returns true if the two arrays contain the
+	 * same data values (irrespective of their order), false otherwise.
+	 *
+	 * @param SMWDataItem[] $oldDataValue
+	 * @param SMWDataItem[] $newDataValue
+	 *
+	 * @return boolean
+	 */
+	private function isEqual( array $oldDataValue, array $newDataValue ) {
+
+		// The hashes of all values of both arrays are taken, then sorted
+		// and finally concatenated, thus creating one long hash out of each
+		// of the data value arrays. These are compared.
+		$values = [];
+		foreach ( $oldDataValue as $v ) {
+			$values[] = $v->getHash();
+		}
+
+		sort( $values );
+		$oldDataValueHash = implode( '___', $values );
+
+		$values = [];
+		foreach ( $newDataValue as $v ) {
+			$values[] = $v->getHash();
+		}
+
+		sort( $values );
+		$newDataValueHash = implode( '___', $values );
+
+		return $oldDataValueHash == $newDataValueHash;
+	}
+
+	private function doNotifyAndPostpone( SemanticData &$semanticData ) {
+
+		if ( !$this->hasDiff() ) {
+			return;
+		}
+
+		$this->notify( $semanticData->getSubject() );
+
+		// If executed from the commandLine (cronJob etc.), do not
+		// suspend the update
+		if ( $this->isCommandLineMode === true ) {
+			return;
+		}
+
+		$previous = $this->store->getSemanticData(
+			$semanticData->getSubject()
+		);
+
+		$semanticDataSerializer = $this->serializerFactory->newSemanticDataSerializer();
+
+		$new = $semanticDataSerializer->serialize(
+			$semanticData
+		);
+
+		// Encode and store the new version of the SemanticData and suspend
+		// the update until ChangePropagationDispatchJob was able to select
+		// all connected entities
+		$previous->addPropertyObjectValue(
+			new DIProperty( DIProperty::TYPE_CHANGE_PROP ),
+			new DIBlob( json_encode( $new ) )
+		);
+
+		$semanticData = $previous;
+	}
+
+}