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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 <boost/optional/optional.hpp>
#include <boost/intrusive_ptr.hpp>
#include "mongo/db/catalog/collection.h"
#include "mongo/db/exec/plan_stage.h"
#include "mongo/db/exec/plan_stats.h"
#include "mongo/db/pipeline/pipeline.h"
#include "mongo/db/record_id.h"
namespace mongo {
/**
* Stage for pulling results out from an aggregation pipeline.
*/
class PipelineProxyStage final : public PlanStage {
public:
PipelineProxyStage(boost::intrusive_ptr<Pipeline> pipeline,
const std::shared_ptr<PlanExecutor>& child,
WorkingSet* ws);
PlanStage::StageState work(WorkingSetID* out) final;
bool isEOF() final;
void doInvalidate(OperationContext* txn, const RecordId& dl, InvalidationType type) final;
//
// Manage our OperationContext.
//
void doDetachFromOperationContext() final;
void doReattachToOperationContext(OperationContext* opCtx) final;
/**
* Make obj the next object returned by getNext().
*/
void pushBack(const BSONObj& obj);
/**
* Return a shared pointer to the PlanExecutor that feeds the pipeline. The returned
* pointer may be NULL.
*/
std::shared_ptr<PlanExecutor> getChildExecutor();
// Returns empty PlanStageStats object
std::unique_ptr<PlanStageStats> getStats() final;
// Not used.
SpecificStats* getSpecificStats() const final {
return NULL;
}
// Not used.
StageType stageType() const final {
return STAGE_PIPELINE_PROXY;
}
static const char* kStageType;
private:
boost::optional<BSONObj> getNextBson();
// Things in the _stash sould be returned before pulling items from _pipeline.
const boost::intrusive_ptr<Pipeline> _pipeline;
std::vector<BSONObj> _stash;
const bool _includeMetaData;
std::weak_ptr<PlanExecutor> _childExec;
// Not owned by us.
WorkingSet* _ws;
};
} // namespace mongo
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