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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.h"
#include "mongo/db/update/modifier_node.h"
#include "mongo/stdx/memory.h"
namespace mongo {
/**
* Represents the application of $max or $min to the value at the end of a path.
*/
class CompareNode : public ModifierNode {
public:
enum class CompareMode { kMax, kMin };
explicit CompareNode(CompareMode mode) : _mode(mode) {}
Status init(BSONElement modExpr, const boost::intrusive_ptr<ExpressionContext>& expCtx) final;
std::unique_ptr<UpdateNode> clone() const final {
return stdx::make_unique<CompareNode>(*this);
}
void setCollator(const CollatorInterface* collator) final;
void acceptVisitor(UpdateNodeVisitor* visitor) final {
visitor->visit(this);
}
protected:
ModifyResult updateExistingElement(mutablebson::Element* element,
std::shared_ptr<FieldRef> elementPath) const final;
void setValueForNewElement(mutablebson::Element* element) const final;
bool allowCreation() const final {
return true;
}
bool canSetObjectValue() const final {
return true;
}
private:
StringData operatorName() const final {
switch (_mode) {
case CompareMode::kMax:
return "$max";
case CompareMode::kMin:
return "$min";
default:
MONGO_UNREACHABLE;
}
}
BSONObj operatorValue() const final {
return BSON("" << _val);
}
CompareMode _mode;
BSONElement _val;
const CollatorInterface* _collator = nullptr;
};
} // namespace mongo
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