wikimedia/mediawiki-extensions-Wikibase

<?php

namespace Wikibase\Lib\Store;

use Wikibase\DataModel\Entity\EntityId;
use Wikibase\DataModel\Entity\PropertyId;
use Wikibase\DataModel\Services\Term\PropertyLabelResolver;
use Wikimedia\ObjectCache\BagOStuff;

/**
 * Resolves property labels (which are unique per language) into entity IDs, uses
 * in-process caching.
 *
 * @license GPL-2.0-or-later
 * @author Daniel Kinzler
 * @author Katie Filbert < aude.wiki@gmail.com >
 */
abstract class AbstractTermPropertyLabelResolver implements PropertyLabelResolver {

    /**
     * The language to use for looking up labels
     *
     * @var string
     */
    protected $languageCode;

    /**
     * @var BagOStuff
     */
    private $cache;

    /**
     * @var int
     */
    private $cacheDuration;

    /**
     * @var string
     */
    private $cacheKey;

    /**
     * Maps labels to property IDs.
     *
     * @var EntityId[]|null
     */
    private $propertiesByLabel = null;

    /**
     * @param string $languageCode The language of the labels to look up (typically, the wiki's content language)
     * @param BagOStuff $cache The cache to use for labels
     * @param int $cacheDuration Number of seconds to keep the cached version for.
     *                              Defaults to 3600 seconds = 1 hour.
     * @param string $cacheKey The cache key to use, auto-generated based on $lang per default.
     *                              Should be set to something including the wiki name
     *                              of the wiki that maintains the properties.
     */
    public function __construct(
        $languageCode,
        BagOStuff $cache,
        $cacheDuration,
        $cacheKey
    ) {
        $this->languageCode = $languageCode;
        $this->cache = $cache;
        $this->cacheDuration = $cacheDuration;
        $this->cacheKey = $cacheKey;
    }

    /**
     * @param string[] $labels
     * @param string $recache Flag, set to 'recache' to fetch fresh data from the database.
     *
     * @return EntityId[] a map of strings from $labels to the corresponding entity ID.
     */
    public function getPropertyIdsForLabels( array $labels, $recache = '' ) {
        $props = $this->getLabelMap( $recache );

        $keys = array_flip( $labels );
        $idsForLabels = array_intersect_key( $props, $keys );

        return $idsForLabels;
    }

    /**
     * Returns a map of labels to EntityIds for all Properties currently defined.
     * The information is taking from the cache if possible, and loaded from a MatchingTermsLookup if not.
     *
     * @param string $recache Flag, set to 'recache' to fetch fresh data from the database.
     *
     * @return EntityId[]
     */
    protected function getLabelMap( $recache = '' ) {
        if ( $this->propertiesByLabel !== null ) {
            // in-process cache
            return $this->propertiesByLabel;
        }

        $cached = $this->getCachedLabelMap( $recache );

        if ( $cached !== false && $cached !== null ) {
            $this->propertiesByLabel = $cached;
            return $this->propertiesByLabel;
        }

        $this->propertiesByLabel = $this->loadProperties();

        $this->cache->set( $this->cacheKey, $this->propertiesByLabel, $this->cacheDuration );

        return $this->propertiesByLabel;
    }

    /**
     * @return EntityId[] Map of labels to EntityIds
     */
    abstract protected function loadProperties(): array;

    /**
     * @param mixed $recache
     *
     * @return array|false
     */
    protected function getCachedLabelMap( $recache ) {
        $cached = false;

        if ( $recache !== 'recache' ) {
            $cached = $this->cache->get( $this->cacheKey );

            if ( is_array( $cached ) && $this->needsRecache( $cached ) ) {
                $cached = false;
            }
        }

        return $cached;
    }

    /**
     * Checks if recache is needed
     *
     * @param array $propertyIds
     *
     * @return bool
     */
    protected function needsRecache( array $propertyIds ) {
        foreach ( $propertyIds as $propertyId ) {
            if ( !( $propertyId instanceof PropertyId ) ) {
                return true;
            }
        }

        return false;
    }

}