owncloud/core

<?php
/**
 * @author Sujith Haridasan <sharidasan@owncloud.com>
 *
 * @copyright Copyright (c) 2018, ownCloud GmbH
 * @license AGPL-3.0
 *
 * This code is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License, version 3,
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License, version 3,
 * along with this program.  If not, see <http://www.gnu.org/licenses/>
 *
 */

namespace OC\Repair;

use OCP\DB\QueryBuilder\IQueryBuilder;
use OCP\IDBConnection;
use OCP\Migration\IOutput;
use OCP\Migration\IRepairStep;

class RepairSubShares implements IRepairStep {
    /** @var IDBConnection  */
    private $connection;

    /** @var  IQueryBuilder */
    private $getDuplicateRows;

    /** @var  IQueryBuilder */
    private $deleteShareId;

    public function __construct(
        IDBConnection $connection
    ) {
        $this->connection = $connection;
    }

    public function getName() {
        return "Repair sub shares";
    }

    /**
     * Get query builder to select rows which have duplicate rows of share
     * @return IQueryBuilder
     */
    private function getSelectQueryToDetectDuplicatesBuilder() {
        /**
         * Retrieves the duplicate rows with different id's
         * of oc_share. The query would look like:
         * SELECT id
         * FROM oc_share
         * WHERE id NOT IN (
         *         SELECT MIN(id)
         *         FROM oc_share
         *         GROUP BY share_with, parent
         * )
         * AND share_type=2;
         */
        $builder = $this->connection->getQueryBuilder();
        $subQuery = $this->connection->getQueryBuilder();
        $subQuery
            ->select($subQuery->createFunction('MIN(`id`)'))
            ->from('share')
            ->groupBy('share_with')
            ->addGroupBy('parent');

        $builder->select('id')
            ->from('share')
            ->where($builder->expr()->notIn('id', $builder->createFunction($subQuery->getSQL())))
            ->andWhere($builder->expr()->eq('share_type', $builder->createNamedParameter(2)));
        return $builder;
    }

    /**
     * Get query builder to delete rows which have duplicate rows of share based
     * on ids
     * @return IQueryBuilder
     */
    private function getDeleteShareIdsBuilder() {
        $builder = $this->connection->getQueryBuilder();
        $builder
            ->delete('share')
            ->where($builder->expr()->in('id', $builder->createParameter('shareIds')));
        return $builder;
    }

    public function run(IOutput $output) {
        $deletedEntries = 0;
        $selectDuplicates = $this->getSelectQueryToDetectDuplicatesBuilder();

        $results = $selectDuplicates->execute();
        $rows = $results->fetchAll();
        $results->closeCursor();
        $rowIds = [];
        if (\count($rows) > 0) {
            $rowIds = \array_map(
                function ($value) {
                    return (int)$value['id'];
                },
                $rows
            );
        }

        if (\count($rows) > 0) {
            //Delete in a batch of 1000 ids
            $deleteShareIds = $this->getDeleteShareIdsBuilder();
            foreach (\array_chunk($rowIds, 1000) as $getIds) {
                $deletedEntries += $deleteShareIds->setParameter('shareIds', $getIds, IQueryBuilder::PARAM_INT_ARRAY)
                    ->execute();
            }
        }

        if ($deletedEntries > 0) {
            $output->info('Removed ' . $deletedEntries . ' shares where duplicate rows where found');
        }
    }
}