wikimedia/mediawiki-extensions-Wikibase

<?php

namespace Wikibase\Lib\Store;

use InvalidArgumentException;
use Wikibase\DataModel\Entity\EntityDocument;

/**
 * An EntityRevision contains a specific revision of an EntityDocument. A revision of an entity is
 * uniquely identified by the tuple ( entity ID, revision ID ).
 *
 * Note that the revision ID alone cannot be relied upon to identify an entity. Revisions of two
 * different entities may have the same revision ID. For more information on the relationship
 * between entities and wiki pages, see docs/entity-storage.wiki.
 *
 * @license GPL-2.0-or-later
 * @author Daniel Kinzler
 */
class EntityRevision {

    public const UNSAVED_REVISION = 0;

    /**
     * @var EntityDocument
     */
    private $entity;

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

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

    /**
     * @param EntityDocument $entity
     * @param int $revisionId Revision ID or 0 for none
     * @param string $mwTimestamp in MediaWiki format or an empty string for none
     *
     * @throws InvalidArgumentException
     */
    public function __construct(
        EntityDocument $entity,
        int $revisionId = self::UNSAVED_REVISION,
        string $mwTimestamp = ''
    ) {
        if ( $revisionId < 0 ) {
            throw new InvalidArgumentException( 'Revision ID must be a non-negative integer.' );
        }

        if ( $mwTimestamp !== '' && !preg_match( '/^\d{14}\z/', $mwTimestamp ) ) {
            throw new InvalidArgumentException( 'Timestamp must be a string of 14 digits or empty.' );
        }

        $this->entity = $entity;
        $this->revisionId = $revisionId;
        $this->mwTimestamp = $mwTimestamp;
    }

    /**
     * @return EntityDocument
     */
    public function getEntity() {
        return $this->entity;
    }

    /**
     * The ID of the revision of the given entity.
     *
     * Note that this number is not guaranteed to be globally unique, nor to be increasing over
     * time.
     *
     * @return int
     */
    public function getRevisionId() {
        return $this->revisionId;
    }

    /**
     * The revision's timestamp. This is purely informational, it does not identify the revision.
     *
     * @return string in MediaWiki format or an empty string
     */
    public function getTimestamp() {
        return $this->mwTimestamp;
    }

}