1 files changed, 185 insertions, 0 deletions
diff --git a/www/wiki/extensions/SemanticMediaWiki/src/Elastic/QueryEngine/SortBuilder.php b/www/wiki/extensions/SemanticMediaWiki/src/Elastic/QueryEngine/SortBuilder.php
new file mode 100644
index 00000000..6d01796e
--- /dev/null
+++ b/www/wiki/extensions/SemanticMediaWiki/src/Elastic/QueryEngine/SortBuilder.php
@@ -0,0 +1,185 @@
+<?php
+
+namespace SMW\Elastic\QueryEngine;
+
+use Psr\Log\LoggerAwareTrait;
+use SMW\DataTypeRegistry;
+use SMW\DIProperty;
+use SMW\Store;
+use SMWQuery as Query;
+
+/**
+ * @license GNU GPL v2+
+ * @since 3.0
+ *
+ * @author mwjames
+ */
+class SortBuilder {
+
+	use LoggerAwareTrait;
+
+	/**
+	 * @var Store
+	 */
+	private $store;
+
+	/**
+	 * @var FieldMapper
+	 */
+	private $fieldMapper;
+
+	/**
+	 * @var string
+	 */
+	private $scoreField;
+
+	/**
+	 * @var boolean
+	 */
+	private $isScoreSort = false;
+
+	/**
+	 * @since 3.0
+	 *
+	 * @param Store $store
+	 */
+	public function __construct( Store $store ) {
+		$this->store = $store;
+		$this->fieldMapper = new FieldMapper();
+	}
+
+	/**
+	 * @since 3.0
+	 *
+	 * @param string $scoreField
+	 */
+	public function setScoreField( $scoreField ) {
+		$this->scoreField = $scoreField;
+	}
+
+	/**
+	 * @since 3.0
+	 *
+	 * @return boolean
+	 */
+	public function isScoreSort() {
+		return $this->isScoreSort;
+	}
+
+	/**
+	 * @since 3.0
+	 *
+	 * @param Query $query
+	 *
+	 * @return array
+	 */
+	public function makeSortField( Query $query ) {
+
+		// @see https://www.elastic.co/guide/en/elasticsearch/reference/current/search-request-sort.html#_memory_considerations
+		// "... the relevant sorted field values are loaded into memory. This means
+		// that per shard, there should be enough memory ... string based types,
+		// the field sorted on should not be analyzed / tokenized ... numeric
+		// types it is recommended to explicitly set the type to narrower types"
+
+		$this->isScoreSort = $query->getOption( Query::SCORE_SORT );
+
+		if ( $query->getOption( Query::SCORE_SORT ) ) {
+			return [ [ '_score' => [ 'order' => $query->getOption( Query::SCORE_SORT ) ] ], [], false, false];
+		}
+
+		return $this->getFields( $query->getSortKeys() );
+	}
+
+	private function getFields( array $sortKeys ) {
+
+		$isRandom = false;
+		$isConstantScore = true;
+		$sort = [];
+		$sortFields = [];
+		$sortKeysCount = count( $sortKeys );
+
+		foreach ( $sortKeys as $key => $order ) {
+			$order = strtolower( $order );
+			$isRandom = strpos( $order, 'rand' ) !== false;
+
+			if ( strtolower( $key ) === $this->scoreField ) {
+				$key = '_score';
+				$this->isScoreSort = true;
+				$isConstantScore = false;
+			}
+
+			if ( $key === '' || $key === '#' ) {
+				$this->addDefaultField( $sort, $order, $sortKeysCount );
+			} else {
+				$this->addField( $sort, $sortFields, $key, $order );
+			}
+		}
+
+		return [ $sort, $sortFields, $isRandom, $isConstantScore ];
+	}
+
+	private function addDefaultField( &$sort, $order, $sortKeysCount ) {
+		$sort['subject.sortkey.sort'] = [ 'order' => $order ];
+
+		// Add title as extra criteria in case an entity uses the same sortkey
+		// to clarify its relative position, @see T:P0416#8
+		// Only add the title as determining factor when no other sort parameter
+		// is available
+		if ( $sortKeysCount == 1 ) {
+			$sort['subject.title.sort'] = [ 'order' => $order ];
+		}
+	}
+
+	private function addField( &$sort, &$sortFields, $key, $order ) {
+
+		$dataTypeRegistry = DataTypeRegistry::getInstance();
+		$chain = false;
+
+		// Chain?
+		if ( strpos( $key, '.' ) !== false ) {
+			$list = explode( '.', $key );
+			$last = current( $list );
+		} else {
+			$list = [ $key ];
+		}
+
+		foreach ( $list as $key ) {
+
+			if ( $key === '_score' ) {
+				$field = '_score';
+			} else {
+				$property = DIProperty::newFromUserLabel( $key );
+
+				$field = $this->fieldMapper->getField( $property, 'Field' );
+
+				$pid = $this->fieldMapper->getPID(
+					$this->store->getObjectIds()->getSMWPropertyID( $property )
+				);
+
+				// Only record the last key to be used as possible existential
+				// enforcement
+				if ( $chain === false ) {
+					$sortFields[] = "$pid.$field";
+				}
+
+				// Use special sort field on mapped fields which is not analyzed
+				if ( $this->sort_field( $field ) ) {
+					$field = "$field.sort";
+				}
+
+				$field = "$pid.$field";
+			}
+
+			if ( !isset( $sort[$field] ) ) {
+				$sort[$field] = [ 'order' => $order ];
+			}
+
+			$chain = true;
+		}
+	}
+
+	private function sort_field( $field ) {
+		return strpos( $field, 'txt' ) !== false || strpos( $field, 'wpgField' ) !== false || strpos( $field, 'uriField' ) !== false;
+	}
+
+}