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/**
* Copyright (C) 2017 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"
#include "mongo/db/pipeline/document_source_single_document_transformation.h"
namespace mongo {
/**
* The $changeNotification stage is an alias for a cursor on oplog followed by a $match stage and a
* transform stage on mongod.
*/
class DocumentSourceChangeNotification final {
public:
class LiteParsed final : public LiteParsedDocumentSource {
public:
static std::unique_ptr<LiteParsed> parse(const AggregationRequest& request,
const BSONElement& spec) {
return stdx::make_unique<LiteParsed>();
}
bool isChangeNotification() const final {
return true;
}
stdx::unordered_set<NamespaceString> getInvolvedNamespaces() const final {
return stdx::unordered_set<NamespaceString>();
}
// TODO SERVER-29138: Add required privileges.
PrivilegeVector requiredPrivileges(bool isMongos) const final {
return {};
}
};
class Transformation : public DocumentSourceSingleDocumentTransformation::TransformerInterface {
public:
~Transformation() = default;
Document applyTransformation(const Document& input) final;
TransformerType getType() const final {
return TransformerType::kChangeNotificationTransformation;
};
void optimize() final{};
Document serializeStageOptions(
boost::optional<ExplainOptions::Verbosity> explain) const final;
DocumentSource::GetDepsReturn addDependencies(DepsTracker* deps) const final;
DocumentSource::GetModPathsReturn getModifiedPaths() const final;
};
/**
* Produce the BSON for the $match stage based on a $changeNotification stage.
*/
static BSONObj buildMatch(BSONElement elem, const NamespaceString& nss);
/**
* Parses a $changeNotification stage from 'elem' and produces the $match and transformation
* stages required.
*/
static std::vector<boost::intrusive_ptr<DocumentSource>> createFromBson(
BSONElement elem, const boost::intrusive_ptr<ExpressionContext>& expCtx);
static boost::intrusive_ptr<DocumentSource> createTransformationStage(
const boost::intrusive_ptr<ExpressionContext>& pExpCtx);
private:
// It is illegal to construct a DocumentSourceChangeNotification directly, use createFromBson()
// instead.
DocumentSourceChangeNotification() = default;
};
} // namespace mongo
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