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/**
* Copyright (C) 2016 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/pipeline/document_source.h"
namespace mongo {
class DocumentSourceOut final : public DocumentSourceNeedsMongod, public SplittableDocumentSource {
public:
static std::unique_ptr<LiteParsedDocumentSourceForeignCollections> liteParse(
const AggregationRequest& request, const BSONElement& spec);
// virtuals from DocumentSource
~DocumentSourceOut() final;
GetNextResult getNext() final;
const char* getSourceName() const final;
Value serialize(boost::optional<ExplainOptions::Verbosity> explain = boost::none) const final;
GetDepsReturn getDependencies(DepsTracker* deps) const final;
StageConstraints constraints() const final {
StageConstraints constraints;
constraints.mustRunOnPrimaryShardIfSharded = true;
constraints.isAllowedInsideFacetStage = false;
constraints.requiredPosition = StageConstraints::PositionRequirement::kLast;
return constraints;
}
// Virtuals for SplittableDocumentSource
boost::intrusive_ptr<DocumentSource> getShardSource() final {
return NULL;
}
boost::intrusive_ptr<DocumentSource> getMergeSource() final {
return this;
}
const NamespaceString& getOutputNs() const {
return _outputNs;
}
/**
Create a document source for output and pass-through.
This can be put anywhere in a pipeline and will store content as
well as pass it on.
@param pBsonElement the raw BSON specification for the source
@param pExpCtx the expression context for the pipeline
@returns the newly created document source
*/
static boost::intrusive_ptr<DocumentSource> createFromBson(
BSONElement elem, const boost::intrusive_ptr<ExpressionContext>& pExpCtx);
private:
DocumentSourceOut(const NamespaceString& outputNs,
const boost::intrusive_ptr<ExpressionContext>& pExpCtx);
/**
* Sets '_tempNs' to a unique temporary namespace, makes sure the output collection isn't
* sharded or capped, and saves the collection options and indexes of the target collection.
* Then creates the temporary collection we will insert into by copying the collection options
* and indexes from the target collection.
*
* Sets '_initialized' to true upon completion.
*/
void initialize();
/**
* Inserts all of 'toInsert' into the temporary collection.
*/
void spill(const std::vector<BSONObj>& toInsert);
bool _initialized = false;
bool _done = false;
// Holds on to the original collection options and index specs so we can check they didn't
// change during computation.
BSONObj _originalOutOptions;
std::list<BSONObj> _originalIndexes;
NamespaceString _tempNs; // output goes here as it is being processed.
const NamespaceString _outputNs; // output will go here after all data is processed.
};
} // namespace mongo
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