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/**
* Copyright (C) 2023-present MongoDB, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the Server Side Public License, version 1,
* as published by MongoDB, Inc.
*
* 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
* Server Side Public License for more details.
*
* You should have received a copy of the Server Side Public License
* along with this program. If not, see
* <http://www.mongodb.com/licensing/server-side-public-license>.
*
* 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 Server Side 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 <queue>
#include "mongo/db/pipeline/document_source.h"
namespace mongo {
class DocumentSourceChangeStreamSplitLargeEvent : public DocumentSource {
public:
static constexpr StringData kStageName = "$changeStreamSplitLargeEvent"_sd;
static constexpr size_t kBSONObjMaxChangeEventSize = BSONObjMaxInternalSize - (8 * 1024);
static boost::intrusive_ptr<DocumentSourceChangeStreamSplitLargeEvent> create(
const boost::intrusive_ptr<ExpressionContext>& expCtx,
const DocumentSourceChangeStreamSpec& spec);
static boost::intrusive_ptr<DocumentSourceChangeStreamSplitLargeEvent> createFromBson(
BSONElement elem, const boost::intrusive_ptr<ExpressionContext>& expCtx);
DocumentSource::GetModPathsReturn getModifiedPaths() const final;
// This stage does not reference any user or system variables.
void addVariableRefs(std::set<Variables::Id>* refs) const final {}
Value serialize(SerializationOptions opts = SerializationOptions()) const final override;
StageConstraints constraints(Pipeline::SplitState pipeState) const final;
void validatePipelinePosition(bool alreadyOptimized,
Pipeline::SourceContainer::const_iterator pos,
const Pipeline::SourceContainer& container) const final;
boost::optional<DistributedPlanLogic> distributedPlanLogic() final {
return boost::none;
}
const char* getSourceName() const final {
return kStageName.rawData();
}
protected:
Pipeline::SourceContainer::iterator doOptimizeAt(Pipeline::SourceContainer::iterator itr,
Pipeline::SourceContainer* container) final;
DocumentSource::GetNextResult doGetNext() final;
private:
// This constructor is private, callers should use the 'create()' method above.
DocumentSourceChangeStreamSplitLargeEvent(const boost::intrusive_ptr<ExpressionContext>& expCtx,
boost::optional<ResumeTokenData> resumeAfterSplit);
Document _popFromQueue();
/**
* In case of resume after split, check whether 'eventDoc' is the split event. If so, extract
* and return the resume token's fragment number. Otherwise, return zero.
*/
size_t _handleResumeAfterSplit(const Document& eventDoc, size_t eventBsonSize);
boost::optional<ResumeTokenData> _resumeAfterSplit;
std::queue<Document> _splitEventQueue;
};
} // namespace mongo
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