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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 <vector>
#include "mongo/db/bson/dotted_path_support.h"
#include "mongo/db/catalog/collection.h"
#include "mongo/db/geo/shapes.h"
#include "mongo/db/record_id.h"
namespace mongo {
namespace dps = ::mongo::dotted_path_support;
class GeoHaystackSearchHopper {
public:
/**
* Constructed with a point, a max distance from that point, and a max number of
* matched points to store.
* @param n The centroid that we're searching
* @param maxDistance The maximum distance to consider from that point
* @param limit The maximum number of results to return
* @param geoField Which field in the provided RecordId has the point to test.
*/
GeoHaystackSearchHopper(OperationContext* opCtx,
const BSONObj& nearObj,
double maxDistance,
unsigned limit,
const std::string& geoField,
const Collection* collection)
: _opCtx(opCtx),
_collection(collection),
_near(nearObj),
_maxDistance(maxDistance),
_limit(limit),
_geoField(geoField) {}
// Consider the point in loc, and keep it if it's within _maxDistance (and we have space for
// it)
void consider(const RecordId& loc) {
if (limitReached())
return;
Point p(dps::extractElementAtPath(_collection->docFor(_opCtx, loc).value(), _geoField));
if (distance(_near, p) > _maxDistance)
return;
_locs.push_back(loc);
}
int appendResultsTo(BSONArrayBuilder* b) {
for (unsigned i = 0; i < _locs.size(); i++)
b->append(_collection->docFor(_opCtx, _locs[i]).value());
return _locs.size();
}
// Have we stored as many points as we can?
bool limitReached() const {
return _locs.size() >= _limit;
}
private:
OperationContext* _opCtx;
const Collection* _collection;
Point _near;
double _maxDistance;
unsigned _limit;
const std::string _geoField;
std::vector<RecordId> _locs;
};
} // namespace mongo
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