/**
 *    Copyright (C) 2018-present MongoDB, Inc.
 *
 *    This program is free software: you can redistribute it and/or modify
 *    it under the terms of the Server Side Public License, version 1,
 *    as published by MongoDB, Inc.
 *
 *    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
 *    Server Side Public License for more details.
 *
 *    You should have received a copy of the Server Side Public License
 *    along with this program. If not, see
 *    <http://www.mongodb.com/licensing/server-side-public-license>.
 *
 *    As a special exception, the copyright holders give permission to link the
 *    code of portions of this program with the OpenSSL library under certain
 *    conditions as described in each individual source file and distribute
 *    linked combinations including the program with the OpenSSL library. You
 *    must comply with the Server Side Public License in all respects for
 *    all of the code used other than as permitted herein. If you modify file(s)
 *    with this exception, you may extend this exception to your version of the
 *    file(s), but you are not obligated to do so. If you do not wish to do so,
 *    delete this exception statement from your version. If you delete this
 *    exception statement from all source files in the program, then also delete
 *    it in the license file.
 */

#include "mongo/platform/basic.h"

#include "mongo/db/update/update_leaf_node.h"

#include "mongo/util/str.h"

namespace mongo {

void UpdateLeafNode::checkViability(mutablebson::Element element,
                                    const FieldRef& pathToCreate,
                                    const FieldRef& pathTaken) {
    invariant(!pathToCreate.empty());

    if (element.getType() == BSONType::Object) {
        // 'pathTaken' leads to an object, so we know it will be possible to create 'pathToCreate'
        // at that path.
    } else if (element.getType() == BSONType::Array &&
               str::parseUnsignedBase10Integer(pathToCreate.getPart(0))) {
        // 'pathTaken' leads to an array, so we know we can add elements at that path so long as the
        // next component is a valid array index. We don't check, but we expect that the index will
        // be out of bounds. (Otherwise it would be part of 'pathTaken' and we wouldn't need to
        // create it.)
    } else {
        uasserted(ErrorCodes::PathNotViable,
                  str::stream() << "Cannot use the part (" << pathToCreate.getPart(0) << ") of ("
                                << pathTaken.dottedField() << "." << pathToCreate.dottedField()
                                << ") to traverse the element ({" << element.toString() << "})");
    }
}

}  // namespace mongo