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/**
* Copyright (C) 2014 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 "mongo/db/diskloc.h"
#include "mongo/db/jsobj.h"
#include "mongo/db/exec/plan_stage.h"
#include "mongo/db/matcher/expression.h"
namespace mongo {
/**
* KeepMutationsStage passes all of its child's data through until the child is EOF.
* It then returns all flagged elements in the WorkingSet that pass the stage's filter.
*
* This stage is used to merge results that are invalidated mid-query back into the query
* results when possible. The query planner is responsible for determining when it's valid to
* merge these results.
*/
class KeepMutationsStage : public PlanStage {
public:
KeepMutationsStage(const MatchExpression* filter, WorkingSet* ws, PlanStage* child);
virtual ~KeepMutationsStage();
virtual bool isEOF();
virtual StageState work(WorkingSetID* out);
virtual void prepareToYield();
virtual void recoverFromYield();
virtual void invalidate(const DiskLoc& dl, InvalidationType type);
virtual std::vector<PlanStage*> getChildren() const;
virtual StageType stageType() const { return STAGE_KEEP_MUTATIONS; }
virtual PlanStageStats* getStats();
virtual const CommonStats* getCommonStats();
virtual const SpecificStats* getSpecificStats();
static const char* kStageType;
private:
// Not owned here.
WorkingSet* _workingSet;
scoped_ptr<PlanStage> _child;
// Not owned here. Should be the full query expression tree.
const MatchExpression* _filter;
// We read from our child...
bool _doneReadingChild;
// ...until it's out of results, at which point we put any flagged results back in the query
// stream.
bool _doneReturningFlagged;
// Stats
CommonStats _commonStats;
unordered_set<WorkingSetID>::const_iterator _flaggedIterator;
};
} // namespace mongo
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