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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/>.
*
* 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 <vector>
#include "mongo/db/diskloc.h"
#include "mongo/db/jsobj.h"
#include "mongo/db/matcher.h"
#include "mongo/db/exec/plan_stage.h"
#include "mongo/platform/unordered_map.h"
namespace mongo {
// External params for the sort stage. Declared below.
class SortStageParams;
/**
* Sorts the input received from the child according to the sort pattern provided.
*
* Preconditions: For each field in 'pattern', all inputs in the child must handle a
* getFieldDotted for that field.
*/
class SortStage : public PlanStage {
public:
SortStage(const SortStageParams& params, WorkingSet* ws, PlanStage* child);
virtual ~SortStage();
virtual bool isEOF();
virtual StageState work(WorkingSetID* out);
virtual void prepareToYield();
virtual void recoverFromYield();
virtual void invalidate(const DiskLoc& dl);
PlanStageStats* getStats();
private:
// Not owned by us.
WorkingSet* _ws;
// Where we're reading data to sort from.
scoped_ptr<PlanStage> _child;
// Our sort pattern.
BSONObj _pattern;
// We read the child into this.
vector<WorkingSetID> _data;
// Have we sorted our data?
bool _sorted;
// Iterates through _data post-sort returning it.
vector<WorkingSetID>::iterator _resultIterator;
// We buffer a lot of data and we want to look it up by DiskLoc quickly upon invalidation.
typedef unordered_map<DiskLoc, WorkingSetID, DiskLoc::Hasher> DataMap;
DataMap _wsidByDiskLoc;
// Stats
CommonStats _commonStats;
SortStats _specificStats;
};
// Parameters that must be provided to a SortStage
class SortStageParams {
public:
//SortStageParams() : limit(0) { }
// How we're sorting.
BSONObj pattern;
// TODO: Implement this.
// Must be >= 0. Equal to 0 for no limit.
// int limit;
};
} // namespace mongo
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