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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/bson/mutable/document.h"
#include "mongo/bson/mutable/element.h"
#include "mongo/db/bson/dotted_path_support.h"
#include "mongo/db/jsobj.h"
#include "mongo/db/query/collation/collator_interface.h"
namespace mongo {
// Extracts the value for 'pattern' for both 'lhs' and 'rhs' and return true if 'lhs' <
// 'rhs'. We expect that both 'lhs' and 'rhs' be key patterns.
struct PatternElementCmp {
PatternElementCmp() = default;
PatternElementCmp(const BSONObj& pattern, const CollatorInterface* collator)
: sortPattern(pattern), useWholeValue(pattern.hasField("")), collator(collator) {}
bool operator()(const mutablebson::Element& lhs, const mutablebson::Element& rhs) const {
namespace dps = ::mongo::dotted_path_support;
if (useWholeValue) {
const int comparedValue = lhs.compareWithElement(rhs, collator, false);
const bool reversed = (sortPattern.firstElement().number() < 0);
return (reversed ? comparedValue > 0 : comparedValue < 0);
} else {
// TODO: Push on to mutable in the future, and to support non-contiguous Elements.
BSONObj lhsObj =
lhs.getType() == Object ? lhs.getValueObject() : lhs.getValue().wrap("");
BSONObj rhsObj =
rhs.getType() == Object ? rhs.getValueObject() : rhs.getValue().wrap("");
BSONObj lhsKey = dps::extractElementsBasedOnTemplate(lhsObj, sortPattern, true);
BSONObj rhsKey = dps::extractElementsBasedOnTemplate(rhsObj, sortPattern, true);
return lhsKey.woCompare(rhsKey, sortPattern, false, collator) < 0;
}
}
BSONObj sortPattern;
bool useWholeValue = true;
const CollatorInterface* collator = nullptr;
};
} // namespace mongo
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