wikimedia/mediawiki-extensions-Wikibase

<?php

namespace Wikibase\DataModel\Services\Lookup;

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

/**
 * EntityLookup that counts how many entities have been loaded through it and throws
 * an exception once to many entities have been loaded.
 *
 * This is needed to limit the number of entities that can be loaded via some
 * user controlled features, like entity access in Lua.
 *
 * @since 2.0
 *
 * @license GPL-2.0-or-later
 * @author Marius Hoch < hoo@online.de >
 */
class RestrictedEntityLookup implements EntityLookup {

    /**
     * @var EntityLookup
     */
    private $entityLookup;

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

    /**
     * @var bool[] Entity id serialization => bool
     */
    private $entitiesAccessed = [];

    /**
     * @var int
     */
    private $entityAccessCount = 0;

    /**
     * @param EntityLookup $entityLookup
     * @param int $entityAccessLimit
     *
     * @throws InvalidArgumentException
     */
    public function __construct( EntityLookup $entityLookup, $entityAccessLimit ) {
        if ( !is_int( $entityAccessLimit ) || $entityAccessLimit < 1 ) {
            throw new InvalidArgumentException( '$entityAccessLimit must be a positive integer' );
        }

        $this->entityLookup = $entityLookup;
        $this->entityAccessLimit = $entityAccessLimit;
    }

    /**
     * @see EntityLookup::getEntity
     *
     * @param EntityId $entityId
     *
     * @throws EntityAccessLimitException
     * @return EntityDocument
     */
    public function getEntity( EntityId $entityId ) {
        $entityIdSerialization = $entityId->getSerialization();

        if ( !array_key_exists( $entityIdSerialization, $this->entitiesAccessed ) ) {
            $this->entityAccessCount++;
            $this->entitiesAccessed[$entityIdSerialization] = true;
        }

        if ( $this->entityAccessCount > $this->entityAccessLimit ) {
            throw new EntityAccessLimitException(
                $entityId,
                'To many entities loaded, must not load more than ' . $this->entityAccessLimit . ' entities.'
            );
        }

        return $this->entityLookup->getEntity( $entityId );
    }

    /**
     * @see EntityLookup::hasEntity
     *
     * @param EntityId $entityId
     *
     * @return bool
     * @throws EntityLookupException
     */
    public function hasEntity( EntityId $entityId ) {
        return $this->entityLookup->hasEntity( $entityId );
    }

    /**
     * Returns the number of entities already loaded via this object.
     *
     * @since 2.0
     *
     * @return int
     */
    public function getEntityAccessCount() {
        return $this->entityAccessCount;
    }

    /**
     * Resets the number and list of entities loaded via this object.
     *
     * @since 3.4
     */
    public function reset() {
        $this->entityAccessCount = 0;
        $this->entitiesAccessed = [];
    }

    /**
     * Whether an entity has been accessed before via this RestrictedEntityLookup.
     *
     * @since 2.0
     *
     * @param EntityId $entityId
     *
     * @return bool
     */
    public function entityHasBeenAccessed( EntityId $entityId ) {
        $entityIdSerialization = $entityId->getSerialization();

        return array_key_exists( $entityIdSerialization, $this->entitiesAccessed );
    }

}