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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 "mongo/db/exec/plan_stage.h"
#include "mongo/db/jsobj.h"
#include "mongo/db/matcher/expression.h"
#include "mongo/db/record_id.h"
#include "mongo/platform/unordered_set.h"
namespace mongo {
/**
* This stage outputs the union of its children. It optionally deduplicates on DiskLoc.
*
* Preconditions: Valid DiskLoc.
*
* If we're deduping, we may fail to dedup any invalidated DiskLoc properly.
*/
class OrStage : public PlanStage {
public:
OrStage(WorkingSet* ws, bool dedup, const MatchExpression* filter);
virtual ~OrStage();
void addChild(PlanStage* child);
virtual bool isEOF();
virtual StageState work(WorkingSetID* out);
virtual void saveState();
virtual void restoreState(OperationContext* opCtx);
virtual void invalidate(OperationContext* txn, const DiskLoc& dl, InvalidationType type);
virtual std::vector<PlanStage*> getChildren() const;
virtual StageType stageType() const { return STAGE_OR; }
virtual PlanStageStats* getStats();
virtual const CommonStats* getCommonStats();
virtual const SpecificStats* getSpecificStats();
static const char* kStageType;
private:
// Not owned by us.
WorkingSet* _ws;
// The filter is not owned by us.
const MatchExpression* _filter;
// Owned by us.
std::vector<PlanStage*> _children;
// Which of _children are we calling work(...) on now?
size_t _currentChild;
// True if we dedup on DiskLoc, false otherwise.
bool _dedup;
// Which DiskLocs have we returned?
unordered_set<DiskLoc, DiskLoc::Hasher> _seen;
// Stats
CommonStats _commonStats;
OrStats _specificStats;
};
} // namespace mongo
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