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/**
* Copyright (C) 2021-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 "mongo/db/pipeline/document_source_change_stream.h"
namespace mongo {
/**
* A custom subclass of DocumentSourceMatch which is used to generate a $match stage to be applied
* on the oplog. The stage requires itself to be the first stage in the pipeline.
*/
class DocumentSourceOplogMatch final : public DocumentSourceMatch,
public ChangeStreamStageSerializationInterface {
public:
static constexpr StringData kStageName = "$_internalChangeStreamOplogMatch"_sd;
DocumentSourceOplogMatch(BSONObj filter, const boost::intrusive_ptr<ExpressionContext>& expCtx)
: DocumentSourceMatch(std::move(filter), expCtx) {
// A change stream pipeline should always create a tailable + awaitData cursor.
expCtx->tailableMode = TailableModeEnum::kTailableAndAwaitData;
}
DocumentSourceOplogMatch(const DocumentSourceOplogMatch& other) : DocumentSourceMatch(other) {}
virtual boost::intrusive_ptr<DocumentSourceMatch> clone() const {
return make_intrusive<std::decay_t<decltype(*this)>>(*this);
}
static boost::intrusive_ptr<DocumentSource> createFromBson(
BSONElement elem, const boost::intrusive_ptr<ExpressionContext>& pExpCtx);
static boost::intrusive_ptr<DocumentSourceOplogMatch> create(
const boost::intrusive_ptr<ExpressionContext>& expCtx, bool showMigrationEvents);
const char* getSourceName() const final;
GetNextResult doGetNext() final {
// We should never execute this stage directly. We expect this stage to be absorbed into the
// cursor feeding the pipeline, and executing this stage may result in the use of the wrong
// collation. The comparisons against the oplog must use the simple collation, regardless of
// the collation on the ExpressionContext.
MONGO_UNREACHABLE;
}
StageConstraints constraints(Pipeline::SplitState pipeState) const final;
Value serialize(boost::optional<ExplainOptions::Verbosity> explain) const final {
return ChangeStreamStageSerializationInterface::serializeToValue(explain);
}
private:
Value serializeLegacy(boost::optional<ExplainOptions::Verbosity> explain) const final;
Value serializeLatest(boost::optional<ExplainOptions::Verbosity> explain) const final;
};
} // namespace mongo
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