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/**
* Copyright (C) 2013 10gen 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/>.
*/
#pragma once
#include "mongo/base/status.h"
#include "mongo/db/index/btree_access_method_internal.h"
#include "mongo/db/index/index_descriptor.h"
#include "mongo/db/jsobj.h"
namespace mongo {
/**
* Maps (lat, lng) to the bucketSize-sided square bucket that contains it.
* Examines all documents in a given radius of a given point.
* Returns all documents that match a given search restriction.
* See http://dochub.mongodb.org/core/haystackindexes
*
* Use when you want to look for restaurants within 25 miles with a certain name.
* Don't use when you want to find the closest open restaurants; see 2d.cpp for that.
*
* Usage:
* db.foo.ensureIndex({ pos : "geoHaystack", type : 1 }, { bucketSize : 1 })
* pos is the name of the field to be indexed that has lat/lng data in an array.
* type is the name of the secondary field to be indexed.
* bucketSize specifies the dimension of the square bucket for the data in pos.
* ALL fields are mandatory.
*/
class HaystackAccessMethod : public BtreeBasedAccessMethod {
public:
using BtreeBasedAccessMethod::_descriptor;
HaystackAccessMethod(IndexDescriptor* descriptor);
virtual ~HaystackAccessMethod() { }
// Not implemented.
virtual Status newCursor(IndexCursor** out);
protected:
friend class GeoHaystackSearchCommand;
void searchCommand(const BSONObj& nearObj, double maxDistance, const BSONObj& search,
BSONObjBuilder* result, unsigned limit);
private:
virtual void getKeys(const BSONObj& obj, BSONObjSet* keys);
// Helper methods called by getKeys:
int hash(const BSONElement& e) const;
string makeString(int hashedX, int hashedY) const;
void addKey(const string& root, const BSONElement& e, BSONObjSet* keys) const;
string _geoField;
vector<string> _otherFields;
double _bucketSize;
};
} // namespace mongo
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