owncloud/core

<?php
/**
 * @author Joas Schilling <coding@schilljs.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\DB\QueryBuilder;

use OCP\DB\QueryBuilder\ILiteral;
use OCP\DB\QueryBuilder\IParameter;
use OCP\DB\QueryBuilder\IQueryFunction;

class QuoteHelper {
    /**
     * @param array|string|ILiteral|IParameter|IQueryFunction $strings string, Literal or Parameter
     * @return array|string
     */
    public function quoteColumnNames($strings) {
        if (!\is_array($strings)) {
            return $this->quoteColumnName($strings);
        }

        $return = [];
        foreach ($strings as $string) {
            $return[] = $this->quoteColumnName($string);
        }

        return $return;
    }

    /**
     * @param string|ILiteral|IParameter|IQueryFunction $string string, Literal or Parameter
     * @return string
     */
    public function quoteColumnName($string) {
        if ($string instanceof IParameter || $string instanceof ILiteral || $string instanceof IQueryFunction) {
            return (string) $string;
        }

        if ($string === null || $string === 'null' || $string === '*') {
            return $string;
        }

        if (!\is_string($string)) {
            throw new \InvalidArgumentException('Only strings, Literals and Parameters are allowed');
        }

        if (\substr_count($string, '.')) {
            list($alias, $columnName) = \explode('.', $string, 2);

            if ($columnName === '*') {
                return $string;
            }

            return $alias . '.`' . $columnName . '`';
        }

        return '`' . $string . '`';
    }
}