wikimedia/mediawiki-extensions-Wikibase

<?php

namespace Wikibase\Repo\Content;

use InvalidArgumentException;
use RuntimeException;
use Wikibase\DataModel\Entity\EntityDocument;
use Wikibase\DataModel\Entity\EntityId;
use Wikibase\Lib\Store\EntityContentDataCodec;

/**
 * EntityHolder implementing deferred deserialization.
 *
 * @license GPL-2.0-or-later
 * @author Daniel Kinzler
 * @author Thiemo Kreuz
 */
class DeferredDecodingEntityHolder implements EntityHolder {

    /**
     * @var EntityDocument|null
     */
    private $entity = null;

    /**
     * @var EntityContentDataCodec
     */
    private $codec;

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

    /**
     * @var string|null
     */
    private $contentFormat;

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

    /**
     * @var EntityId|null
     */
    private $entityId = null;

    /**
     * @param EntityContentDataCodec $codec
     * @param string $blob
     * @param string|null $contentFormat Serialization format to decode the blob, typically
     *  CONTENT_FORMAT_JSON.
     * @param string $entityType
     * @param EntityId|null $entityId
     *
     * @throws InvalidArgumentException
     */
    public function __construct(
        EntityContentDataCodec $codec,
        $blob,
        $contentFormat,
        $entityType,
        EntityId $entityId = null
    ) {
        if ( !is_string( $blob ) ) {
            throw new InvalidArgumentException( '$blob must be a string' );
        }

        if ( $contentFormat !== null && !is_string( $contentFormat ) ) {
            throw new InvalidArgumentException( '$contentFormat must be a string or null' );
        }

        if ( !is_string( $entityType ) ) {
            throw new InvalidArgumentException( '$entityType must be a string' );
        }

        $this->codec = $codec;
        $this->blob = $blob;
        $this->contentFormat = $contentFormat;
        $this->entityType = $entityType;
        $this->entityId = $entityId;
    }

    /**
     * @see EntityHolder::getEntityId
     *
     * This implements lazy deserialization of the blob passed to the constructor.
     *
     * @param string $expectedClass The class with which the result is expected to be compatible.
     * Defaults to EntityDocument.
     *
     * @throws RuntimeException If the entity held by this EntityHolder is not compatible with $expectedClass.
     * @return EntityDocument
     */
    public function getEntity( $expectedClass = EntityDocument::class ) {
        if ( !$this->entity ) {
            $this->entity = $this->codec->decodeEntity( $this->blob, $this->contentFormat );

            if ( !( $this->entity instanceof EntityDocument ) ) {
                throw new RuntimeException( 'Deferred decoding resulted in an incompatible entity, '
                    . 'expected EntityDocument, got ' . get_debug_type( $this->entity ) );
            } elseif ( $this->entity->getType() !== $this->entityType ) {
                throw new RuntimeException( 'Deferred decoding resulted in an incompatible entity, '
                    . 'expected ' . $this->entityType . ', got ' . $this->entity->getType() );
            } elseif ( $this->entity->getId() === null ) {
                throw new RuntimeException( 'Deferred decoding resulted in an incompatible entity, '
                    . 'expected an entity id to be set, got null' );
            } elseif ( $this->entityId && !$this->entity->getId()->equals( $this->entityId ) ) {
                throw new RuntimeException( 'Deferred decoding resulted in an incompatible entity, '
                    . 'expected ' . $this->entityId . ', got ' . $this->entity->getId() );
            }
        }

        if ( !( $this->entity instanceof $expectedClass ) ) {
            throw new RuntimeException( 'Deferred decoding resulted in an incompatible entity, '
                . 'expected ' . $expectedClass . ', got ' . get_class( $this->entity ) );
        }

        return $this->entity;
    }

    /**
     * @see EntityHolder::getEntityId
     *
     * @throws RuntimeException If the entity held by this EntityHolder does not have an id.
     * @return EntityId
     */
    public function getEntityId() {
        if ( !$this->entityId ) {
            $this->entityId = $this->getEntity()->getId();
        }

        return $this->entityId;
    }

    /**
     * @see EntityHolder::getEntityType
     *
     * @return string
     */
    public function getEntityType() {
        return $this->entityType;
    }

}