1 files changed, 197 insertions, 0 deletions
diff --git a/www/wiki/extensions/SemanticMediaWiki/src/SQLStore/QueryEngine/DescriptionInterpreters/ConceptDescriptionInterpreter.php b/www/wiki/extensions/SemanticMediaWiki/src/SQLStore/QueryEngine/DescriptionInterpreters/ConceptDescriptionInterpreter.php
new file mode 100644
index 00000000..82955af1
--- /dev/null
+++ b/www/wiki/extensions/SemanticMediaWiki/src/SQLStore/QueryEngine/DescriptionInterpreters/ConceptDescriptionInterpreter.php
@@ -0,0 +1,197 @@
+<?php
+
+namespace SMW\SQLStore\QueryEngine\DescriptionInterpreters;
+
+use RuntimeException;
+use SMW\Query\Language\ConceptDescription;
+use SMW\Query\Language\Conjunction;
+use SMW\Query\Language\Description;
+use SMW\Query\Language\Disjunction;
+use SMW\Query\Parser as QueryParser;
+use SMW\SQLStore\QueryEngine\DescriptionInterpreter;
+use SMW\SQLStore\QueryEngine\QuerySegment;
+use SMW\SQLStore\QueryEngine\QuerySegmentListBuilder;
+use SMWSQLStore3;
+
+/**
+ * @license GNU GPL v2+
+ * @since 2.2
+ *
+ * @author Markus Krötzsch
+ * @author Jeroen De Dauw
+ * @author mwjames
+ */
+class ConceptDescriptionInterpreter implements DescriptionInterpreter {
+
+	/**
+	 * @var QuerySegmentListBuilder
+	 */
+	private $querySegmentListBuilder;
+
+	/**
+	 * @var QueryParser
+	 */
+	private $queryParser;
+
+	/**
+	 * @since 2.2
+	 *
+	 * @param QuerySegmentListBuilder $querySegmentListBuilder
+	 */
+	public function __construct( QuerySegmentListBuilder $querySegmentListBuilder ) {
+		$this->querySegmentListBuilder = $querySegmentListBuilder;
+	}
+
+	/**
+	 * @since 2.2
+	 *
+	 * @return boolean
+	 */
+	public function canInterpretDescription( Description $description ) {
+		return $description instanceof ConceptDescription;
+	}
+
+	/**
+	 * @since 3.0
+	 *
+	 * @param QueryParser $queryParser
+	 */
+	public function setQueryParser( QueryParser $queryParser ) {
+		$this->queryParser = $queryParser;
+	}
+
+	/**
+	 * @since 2.2
+	 *
+	 * @param Description $description
+	 *
+	 * @return QuerySegment
+	 */
+	public function interpretDescription( Description $description ) {
+
+		$query = new QuerySegment();
+		$concept = $description->getConcept();
+
+		$conceptId = $this->querySegmentListBuilder->getStore()->getObjectIds()->getSMWPageID(
+			$concept->getDBkey(),
+			SMW_NS_CONCEPT,
+			'',
+			''
+		);
+
+		$hash = 'concept-' . $conceptId;
+
+		$this->querySegmentListBuilder->getCircularReferenceGuard()->mark( $hash );
+
+		if ( $this->querySegmentListBuilder->getCircularReferenceGuard()->isCircular( $hash ) ) {
+
+			$this->querySegmentListBuilder->addError(
+				[ 'smw-query-condition-circular', $description->getQueryString() ]
+			);
+
+			return $query;
+		}
+
+		$db = $this->querySegmentListBuilder->getStore()->getConnection( 'mw.db.queryengine' );
+		$row = $this->getConceptForId( $db, $conceptId );
+
+		// No description found, concept does not exist.
+		if ( $row === false ) {
+			$this->querySegmentListBuilder->getCircularReferenceGuard()->unmark( 'concept-' . $conceptId );
+			// keep the above query object, it yields an empty result
+			// TODO: announce an error here? (maybe not, since the query processor can check for
+			// non-existing concept pages which is probably the main reason for finding nothing here)
+			return $query;
+		};
+
+		global $smwgQConceptCaching, $smwgQMaxSize, $smwgQMaxDepth, $smwgQFeatures, $smwgQConceptCacheLifetime;
+
+		$may_be_computed = ( $smwgQConceptCaching == CONCEPT_CACHE_NONE ) ||
+		    ( ( $smwgQConceptCaching == CONCEPT_CACHE_HARD ) && ( ( ~( ~( $row->concept_features + 0 ) | $smwgQFeatures ) ) == 0 ) &&
+		      ( $smwgQMaxSize >= $row->concept_size ) && ( $smwgQMaxDepth >= $row->concept_depth ) );
+
+		if ( $row->cache_date &&
+		     ( ( $row->cache_date > ( strtotime( "now" ) - $smwgQConceptCacheLifetime * 60 ) ) ||
+		       !$may_be_computed ) ) { // Cached concept, use cache unless it is dead and can be revived.
+
+			$query->joinTable = SMWSQLStore3::CONCEPT_CACHE_TABLE;
+			$query->joinfield = "$query->alias.s_id";
+			$query->where = "$query->alias.o_id=" . $db->addQuotes( $conceptId );
+		} elseif ( $row->concept_txt ) { // Parse description and process it recursively.
+			if ( $may_be_computed ) {
+				$description = $this->getConceptQueryDescriptionFrom( $row->concept_txt );
+
+				$this->findCircularDescription(
+					$concept,
+					$description
+				);
+
+				$qid = $this->querySegmentListBuilder->getQuerySegmentFrom( $description );
+
+				if ($qid != -1) {
+					$query = $this->querySegmentListBuilder->findQuerySegment( $qid );
+				} else { // somehow the concept query is no longer valid; maybe some syntax changed (upgrade) or global settings were modified since storing it
+					$this->querySegmentListBuilder->addError( 'smw_emptysubquery' ); // not the right message, but this case is very rare; let us not make detailed messages for this
+				}
+			} else {
+				$this->querySegmentListBuilder->addError(
+					[ 'smw_concept_cache_miss', $concept->getDBkey() ]
+				);
+			}
+		} // else: no cache, no description (this may happen); treat like empty concept
+
+		$this->querySegmentListBuilder->getCircularReferenceGuard()->unmark( $hash );
+
+		return $query;
+	}
+
+	/**
+	 * We bypass the storage interface here (which is legal as we control it,
+	 * and safe if we are careful with changes ...)
+	 *
+	 * This should be faster, but we must implement the unescaping that concepts
+	 * do on getWikiValue
+	 */
+	private function getConceptForId( $db, $id ) {
+		return $db->selectRow(
+			'smw_fpt_conc',
+			[ 'concept_txt', 'concept_features', 'concept_size', 'concept_depth', 'cache_date' ],
+			[ 's_id' => $id ],
+			__METHOD__
+		);
+	}
+
+	/**
+	 * No defaultnamespaces here; If any, these are already in the concept.
+	 * Unescaping is the same as in SMW_DV_Conept's getWikiValue().
+	 */
+	private function getConceptQueryDescriptionFrom( $conceptQuery ) {
+
+		if ( $this->queryParser === null ) {
+			throw new RuntimeException( 'Missing a QueryParser instance' );
+		}
+
+		return $this->queryParser->getQueryDescription(
+			str_replace( [ '&lt;', '&gt;', '&amp;' ], [ '<', '>', '&' ], $conceptQuery )
+		);
+	}
+
+	private function findCircularDescription( $concept, &$description ) {
+
+		if ( $description instanceof ConceptDescription ) {
+			if ( $description->getConcept()->equals( $concept ) ) {
+				$this->querySegmentListBuilder->addError(
+					[ 'smw-query-condition-circular', $description->getQueryString() ]
+				);
+				return;
+			}
+		}
+
+		if ( $description instanceof Conjunction || $description instanceof Disjunction ) {
+			foreach ( $description->getDescriptions() as $desc ) {
+				$this->findCircularDescription( $concept, $desc );
+			}
+		}
+	}
+
+}