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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/db/exec/index_scan.h"
#include "mongo/db/exec/near.h"
#include "mongo/db/exec/plan_stats.h"
#include "mongo/db/exec/working_set.h"
#include "mongo/db/geo/geometry_container.h"
#include "mongo/db/geo/r2_region_coverer.h"
#include "mongo/db/index/index_descriptor.h"
#include "mongo/db/index/s2_common.h"
#include "mongo/db/matcher/expression.h"
#include "mongo/db/matcher/expression_geo.h"
#include "mongo/db/query/index_bounds.h"
#include "third_party/s2/s2cellunion.h"
namespace mongo {
/**
* Generic parameters for a GeoNear search
*/
struct GeoNearParams {
GeoNearParams()
: filter(nullptr), nearQuery(nullptr), addPointMeta(false), addDistMeta(false) {}
// MatchExpression to apply to the index keys and fetched documents
// Not owned here, owned by solution nodes
MatchExpression* filter;
// Index scan bounds, not including the geo bounds
IndexBounds baseBounds;
// Not owned here
const GeoNearExpression* nearQuery;
bool addPointMeta;
bool addDistMeta;
};
/**
* Implementation of GeoNear on top of a 2D index
*/
class GeoNear2DStage final : public NearStage {
public:
GeoNear2DStage(const GeoNearParams& nearParams,
OperationContext* opCtx,
WorkingSet* workingSet,
const IndexDescriptor* twoDIndex);
protected:
StatusWith<CoveredInterval*> nextInterval(OperationContext* opCtx,
WorkingSet* workingSet,
const Collection* collection) final;
StatusWith<double> computeDistance(WorkingSetMember* member) final;
PlanStage::StageState initialize(OperationContext* opCtx,
WorkingSet* workingSet,
WorkingSetID* out) final;
private:
class DensityEstimator {
public:
DensityEstimator(PlanStage::Children* children,
BSONObj infoObj,
const GeoNearParams* nearParams,
const R2Annulus& fullBounds);
PlanStage::StageState work(OperationContext* opCtx,
WorkingSet* workingSet,
const IndexDescriptor* twoDIndex,
WorkingSetID* out,
double* estimatedDistance);
private:
void buildIndexScan(OperationContext* opCtx,
WorkingSet* workingSet,
const IndexDescriptor* twoDIndex);
PlanStage::Children* _children; // Points to PlanStage::_children in the NearStage.
const GeoNearParams* _nearParams; // Not owned here.
const R2Annulus& _fullBounds;
IndexScan* _indexScan = nullptr; // Owned in PlanStage::_children.
std::unique_ptr<GeoHashConverter> _converter;
GeoHash _centroidCell;
unsigned _currentLevel;
};
const GeoNearParams _nearParams;
// The total search annulus
const R2Annulus _fullBounds;
// The current search annulus
R2Annulus _currBounds;
// Amount to increment the next bounds by
double _boundsIncrement;
// Keeps track of the region that has already been scanned
R2CellUnion _scannedCells;
std::unique_ptr<DensityEstimator> _densityEstimator;
};
/**
* Implementation of GeoNear on top of a 2DSphere (S2) index
*/
class GeoNear2DSphereStage final : public NearStage {
public:
GeoNear2DSphereStage(const GeoNearParams& nearParams,
OperationContext* opCtx,
WorkingSet* workingSet,
const IndexDescriptor* s2Index);
~GeoNear2DSphereStage();
protected:
StatusWith<CoveredInterval*> nextInterval(OperationContext* opCtx,
WorkingSet* workingSet,
const Collection* collection) final;
StatusWith<double> computeDistance(WorkingSetMember* member) final;
PlanStage::StageState initialize(OperationContext* opCtx,
WorkingSet* workingSet,
WorkingSetID* out) final;
private:
// Estimate the density of data by search the nearest cells level by level around center.
class DensityEstimator {
public:
DensityEstimator(PlanStage::Children* children,
const GeoNearParams* nearParams,
const S2IndexingParams& indexParams,
const R2Annulus& fullBounds);
// Search for a document in neighbors at current level.
// Return IS_EOF is such document exists and set the estimated distance to the nearest doc.
PlanStage::StageState work(OperationContext* opCtx,
WorkingSet* workingSet,
const IndexDescriptor* s2Index,
WorkingSetID* out,
double* estimatedDistance);
private:
void buildIndexScan(OperationContext* opCtx,
WorkingSet* workingSet,
const IndexDescriptor* s2Index);
PlanStage::Children* _children; // Points to PlanStage::_children in the NearStage.
const GeoNearParams* _nearParams; // Not owned here.
const S2IndexingParams _indexParams;
const R2Annulus& _fullBounds;
int _currentLevel;
IndexScan* _indexScan = nullptr; // Owned in PlanStage::_children.
};
const GeoNearParams _nearParams;
S2IndexingParams _indexParams;
// The total search annulus
const R2Annulus _fullBounds;
// The current search annulus
R2Annulus _currBounds;
// Amount to increment the next bounds by
double _boundsIncrement;
// Keeps track of the region that has already been scanned
S2CellUnion _scannedCells;
std::unique_ptr<DensityEstimator> _densityEstimator;
};
} // namespace mongo
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