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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 <boost/intrusive_ptr.hpp>
#include <boost/optional.hpp>
#include <list>
#include <memory>
#include "mongo/base/string_data.h"
#include "mongo/bson/bsonobj.h"
#include "mongo/db/catalog/collection.h"
#include "mongo/db/exec/document_value/document.h"
#include "mongo/db/pipeline/document_source_cursor.h"
#include "mongo/db/pipeline/expression_context.h"
#include "mongo/db/pipeline/field_path.h"
#include "mongo/db/query/plan_executor.h"
namespace mongo {
/**
* Like DocumentSourceCursor, this stage returns Documents from BSONObjs produced by a PlanExecutor,
* but does extra work to compute distances to satisfy a $near or $nearSphere query.
*/
class DocumentSourceGeoNearCursor final : public DocumentSourceCursor {
public:
/**
* The name of this stage.
*/
static constexpr StringData kStageName = "$geoNearCursor"_sd;
/**
* Create a new DocumentSourceGeoNearCursor. If specified, 'distanceMultiplier' must be
* nonnegative.
*/
static boost::intrusive_ptr<DocumentSourceGeoNearCursor> create(
const CollectionPtr&,
std::unique_ptr<PlanExecutor, PlanExecutor::Deleter>,
const boost::intrusive_ptr<ExpressionContext>&,
FieldPath distanceField,
boost::optional<FieldPath> locationField = boost::none,
double distanceMultiplier = 1.0);
const char* getSourceName() const final;
private:
DocumentSourceGeoNearCursor(const CollectionPtr&,
std::unique_ptr<PlanExecutor, PlanExecutor::Deleter>,
const boost::intrusive_ptr<ExpressionContext>&,
FieldPath distanceField,
boost::optional<FieldPath> locationField,
double distanceMultiplier);
~DocumentSourceGeoNearCursor() = default;
/**
* Transforms 'obj' into a Document, calculating the distance.
*/
Document transformDoc(Document&& obj) const override final;
// The output field in which to store the computed distance.
FieldPath _distanceField;
// The output field to store the point that matched, if specified.
boost::optional<FieldPath> _locationField;
// A multiplicative factor applied to each distance. For example, you can use this to convert
// radian distances into meters by multiplying by the radius of the Earth.
double _distanceMultiplier = 1.0;
};
} // namespace mongo
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