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/**
* 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.
*/
#pragma once
#include "mongo/base/string_data_comparator_interface.h"
#include "mongo/bson/bsonobj_comparator_interface.h"
namespace mongo {
/**
* A BSONObj comparator that supports:
* - Comparing with respect to an ordering spec such as {a: 1, b: -1}.
* - Ignoring field names during comparison.
* - Passing a custom string comparator.
*/
class BSONObjComparator final : public BSONObj::ComparatorInterface {
public:
enum class FieldNamesMode {
kConsider,
kIgnore,
};
/**
* Constructs a BSONObj comparator which will use the 'ordering' pattern for comparisons.
*
* Will not consider BSON field names in comparisons if 'fieldNamesMode' is kIgnore.
*
* If 'stringComparator' is null, uses default binary string comparison. Otherwise,
* 'stringComparator' is used for all string comparisons.
*/
BSONObjComparator(BSONObj ordering,
FieldNamesMode fieldNamesMode,
const StringData::ComparatorInterface* stringComparator)
: _ordering(std::move(ordering)),
_stringComparator(stringComparator),
_rules((fieldNamesMode == FieldNamesMode::kConsider) ? ComparisonRules::kConsiderFieldName
: 0) {}
int compare(const BSONObj& lhs, const BSONObj& rhs) const final {
return lhs.woCompare(rhs, _ordering, _rules, _stringComparator);
}
void hash_combine(size_t& seed, const BSONObj& toHash) const final {
hashCombineBSONObj(seed, toHash, _rules, _stringComparator);
}
private:
BSONObj _ordering;
const StringData::ComparatorInterface* _stringComparator;
ComparisonRulesSet _rules;
};
} // namespace mongo
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