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/**
* Copyright (C) 2020-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.h"
#include "mongo/db/pipeline/document_source_set_window_fields_gen.h"
#include "mongo/db/pipeline/window_function_expression.h"
namespace mongo {
struct WindowFunctionStatement {
std::string fieldName; // top-level fieldname, not a path
boost::intrusive_ptr<window_function::Expression> expr;
WindowFunctionStatement(std::string fieldName,
boost::intrusive_ptr<window_function::Expression> expr)
: fieldName(std::move(fieldName)), expr(std::move(expr)) {}
static WindowFunctionStatement parse(BSONElement elem,
const boost::optional<SortPattern>& sortBy,
ExpressionContext* expCtx);
void serialize(MutableDocument& outputFields,
boost::optional<ExplainOptions::Verbosity> explain) const;
};
/**
* $setWindowFields is an alias: it desugars to some combination of projection, sorting,
* and $_internalSetWindowFields.
*/
namespace document_source_set_window_fields {
constexpr StringData kStageName = "$setWindowFields"_sd;
std::list<boost::intrusive_ptr<DocumentSource>> createFromBson(
BSONElement elem, const boost::intrusive_ptr<ExpressionContext>& pExpCtx);
std::list<boost::intrusive_ptr<DocumentSource>> create(
const boost::intrusive_ptr<ExpressionContext>& expCtx,
boost::optional<boost::intrusive_ptr<Expression>> partitionBy,
const boost::optional<SortPattern>& sortBy,
std::vector<WindowFunctionStatement> outputFields);
} // namespace document_source_set_window_fields
class DocumentSourceInternalSetWindowFields final : public DocumentSource {
public:
static constexpr StringData kStageName = "$_internalSetWindowFields"_sd;
/**
* Parses 'elem' into a $setWindowFields stage, or throws a AssertionException if 'elem' was an
* invalid specification.
*/
static boost::intrusive_ptr<DocumentSource> createFromBson(
BSONElement elem, const boost::intrusive_ptr<ExpressionContext>& pExpCtx);
DocumentSourceInternalSetWindowFields(
const boost::intrusive_ptr<ExpressionContext>& expCtx,
boost::optional<boost::intrusive_ptr<Expression>> partitionBy,
const boost::optional<SortPattern>& sortBy,
std::vector<WindowFunctionStatement> outputFields)
: DocumentSource(kStageName, expCtx),
_partitionBy(partitionBy),
_sortBy(std::move(sortBy)),
_outputFields(std::move(outputFields)) {}
StageConstraints constraints(Pipeline::SplitState pipeState) const final {
return StageConstraints(StreamType::kBlocking,
PositionRequirement::kNone,
HostTypeRequirement::kNone,
DiskUseRequirement::kWritesTmpData,
FacetRequirement::kAllowed,
TransactionRequirement::kAllowed,
LookupRequirement::kAllowed,
UnionRequirement::kAllowed);
}
const char* getSourceName() const {
return kStageName.rawData();
};
boost::optional<DistributedPlanLogic> distributedPlanLogic() {
// Force to run on the merging half for now.
return DistributedPlanLogic{nullptr, this, boost::none};
}
Value serialize(boost::optional<ExplainOptions::Verbosity> explain) const;
DocumentSource::GetNextResult doGetNext();
private:
DocumentSource::GetNextResult getNextInput();
boost::optional<boost::intrusive_ptr<Expression>> _partitionBy;
boost::optional<SortPattern> _sortBy;
std::vector<WindowFunctionStatement> _outputFields;
};
} // namespace mongo
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