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/**
* Copyright (C) 2013 MongoDB Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* 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
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* 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 GNU Affero General 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 <queue>
#include "mongo/db/exec/plan_stage.h"
#include "mongo/db/geo/geoquery.h"
#include "mongo/db/geo/s2common.h"
#include "mongo/db/index/index_descriptor.h"
#include "mongo/db/jsobj.h"
#include "mongo/db/matcher/expression.h"
#include "mongo/db/query/index_bounds.h"
#include "mongo/platform/unordered_set.h"
#include "third_party/s2/s2cap.h"
#include "third_party/s2/s2regionintersection.h"
namespace mongo {
struct S2NearParams {
S2NearParams() : collection(NULL) { }
Collection* collection;
BSONObj indexKeyPattern;
NearQuery nearQuery;
IndexBounds baseBounds;
MatchExpression* filter;
bool addPointMeta;
bool addDistMeta;
};
/**
* Executes a geoNear search. Is a leaf node. Output type is LOC_AND_UNOWNED_OBJ.
*/
class S2NearStage : public PlanStage {
public:
/**
* Takes: index to scan over, MatchExpression with near point, other MatchExpressions for
* covered data,
*/
S2NearStage(const S2NearParams& params, WorkingSet* ws);
virtual ~S2NearStage();
StageState work(WorkingSetID* out);
bool isEOF();
void prepareToYield();
void recoverFromYield();
void invalidate(const DiskLoc& dl, InvalidationType type);
PlanStageStats* getStats();
private:
void init();
StageState addResultToQueue(WorkingSetID* out);
void nextAnnulus();
bool _worked;
S2NearParams _params;
WorkingSet* _ws;
// This is the "array index" of the key field that is the near field. We use this to do
// cheap is-this-doc-in-the-annulus testing. We also need to know where to stuff the index
// bounds for the various annuluses/annuli.
int _nearFieldIndex;
// Geo filter in index scan (which is owned by fetch stage in _child).
scoped_ptr<MatchExpression> _keyGeoFilter;
scoped_ptr<PlanStage> _child;
// The S2 machinery that represents the search annulus. We keep this around after bounds
// generation to check for intersection.
S2Cap _innerCap;
S2Cap _outerCap;
S2RegionIntersection _annulus;
// We use this to hold on to the results in an annulus. Results are sorted to have
// decreasing distance.
struct Result {
Result(WorkingSetID wsid, double dist) : id(wsid), distance(dist) { }
bool operator<(const Result& other) const {
// We want increasing distance, not decreasing, so we reverse the <.
return distance > other.distance;
}
WorkingSetID id;
double distance;
};
// Our index scans aren't deduped so we might see the same doc twice in a given
// annulus.
unordered_set<DiskLoc, DiskLoc::Hasher> _seenInScan;
// We compute an annulus of results and cache it here.
priority_queue<Result> _results;
// For fast invalidation. Perhaps not worth it.
unordered_map<DiskLoc, WorkingSetID, DiskLoc::Hasher> _invalidationMap;
// Geo-related variables.
// At what min distance (arc length) do we start looking for results?
double _minDistance;
// What's the max distance (arc length) we're willing to look for results?
double _maxDistance;
// These radii define the annulus we're currently looking at.
double _innerRadius;
double _outerRadius;
// True if we are looking at last annulus
bool _outerRadiusInclusive;
// When we search the next annulus, what to adjust our radius by? Grows when we search an
// annulus and find no results.
double _radiusIncrement;
// Did we encounter an unrecoverable error?
bool _failed;
// Have we init()'d yet?
bool _initted;
// What index are we searching over?
IndexDescriptor* _descriptor;
CommonStats _commonStats;
};
} // namespace mongo
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