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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/accumulator.h"
#include "mongo/db/pipeline/window_function/window_function_covariance.h"
#include "mongo/db/pipeline/window_function/window_function_integral.h"
namespace mongo {
/**
* This class is a base class for accumulators that are applied only in window functions. Some
* functionality supported in $group, e.g. merging on process(), is not supported in
* AccumulatorForWindowFunctions. Some certain group-related methods should also be unreachable
* here.
*/
class AccumulatorForWindowFunctions : public AccumulatorState {
public:
AccumulatorForWindowFunctions(ExpressionContext* const expCtx) : AccumulatorState(expCtx) {}
ExpressionNary::Associativity getAssociativity() const final {
tasserted(5424002,
str::stream() << "Invalid call to getAssociativity() in accumulator "
<< getOpName());
return ExpressionNary::Associativity::kNone;
}
bool isCommutative() const final {
tasserted(5424003,
str::stream() << "Invalid call to isCommutative in accumulator " << getOpName());
}
};
class AccumulatorCovariance : public AccumulatorForWindowFunctions {
public:
AccumulatorCovariance(ExpressionContext* expCtx, bool isSamp);
void processInternal(const Value& input, bool merging) final;
Value getValue(bool toBeMerged) final;
void reset() final;
const char* getOpName() const final {
return (_covarianceWF.isSample() ? "$covarianceSamp" : "$covariancePop");
}
private:
WindowFunctionCovariance _covarianceWF;
};
class AccumulatorCovarianceSamp final : public AccumulatorCovariance {
public:
static constexpr auto kName = "$covarianceSamp"_sd;
explicit AccumulatorCovarianceSamp(ExpressionContext* const expCtx)
: AccumulatorCovariance(expCtx, true) {}
static boost::intrusive_ptr<AccumulatorState> create(ExpressionContext* expCtx);
};
class AccumulatorCovariancePop final : public AccumulatorCovariance {
public:
static constexpr auto kName = "$covariancePop"_sd;
explicit AccumulatorCovariancePop(ExpressionContext* const expCtx)
: AccumulatorCovariance(expCtx, false) {}
static boost::intrusive_ptr<AccumulatorState> create(ExpressionContext* expCtx);
};
class AccumulatorRankBase : public AccumulatorForWindowFunctions {
public:
explicit AccumulatorRankBase(ExpressionContext* expCtx);
void reset();
Value getValue(bool toBeMerged) final {
return Value::createIntOrLong(_lastRank);
}
protected:
long long _lastRank = 0;
boost::optional<Value> _lastInput = boost::none;
};
class AccumulatorRank : public AccumulatorRankBase {
public:
static constexpr auto kName = "$rank"_sd;
const char* getOpName() const final {
return kName.rawData();
}
explicit AccumulatorRank(ExpressionContext* const expCtx) : AccumulatorRankBase(expCtx) {}
void processInternal(const Value& input, bool merging) final;
static boost::intrusive_ptr<AccumulatorState> create(ExpressionContext* expCtx);
void reset() final;
private:
size_t _numSameRank = 1;
};
class AccumulatorDocumentNumber : public AccumulatorRankBase {
public:
static constexpr auto kName = "$documentNumber"_sd;
const char* getOpName() const final {
return kName.rawData();
}
explicit AccumulatorDocumentNumber(ExpressionContext* const expCtx)
: AccumulatorRankBase(expCtx) {}
void processInternal(const Value& input, bool merging) final;
static boost::intrusive_ptr<AccumulatorState> create(ExpressionContext* expCtx);
};
class AccumulatorDenseRank : public AccumulatorRankBase {
public:
static constexpr auto kName = "$denseRank"_sd;
const char* getOpName() const final {
return kName.rawData();
}
explicit AccumulatorDenseRank(ExpressionContext* const expCtx) : AccumulatorRankBase(expCtx) {}
void processInternal(const Value& input, bool merging) final;
static boost::intrusive_ptr<AccumulatorState> create(ExpressionContext* expCtx);
};
class AccumulatorIntegral : public AccumulatorForWindowFunctions {
public:
static constexpr auto kName = "$integral"_sd;
const char* getOpName() const final {
return kName.rawData();
}
explicit AccumulatorIntegral(ExpressionContext* expCtx,
boost::optional<long long> unitMillis = boost::none);
void processInternal(const Value& input, bool merging) final;
Value getValue(bool toBeMerged) final;
void reset() final;
static boost::intrusive_ptr<AccumulatorState> create(
ExpressionContext* expCtx, boost::optional<long long> unitMillis = boost::none);
private:
WindowFunctionIntegral _integralWF;
};
class AccumulatorLocf : public AccumulatorForWindowFunctions {
public:
static constexpr auto kName = "$locf"_sd;
const char* getOpName() const final {
return kName.rawData();
}
explicit AccumulatorLocf(ExpressionContext* expCtx);
void processInternal(const Value& input, bool merging) final;
Value getValue(bool toBeMerged) final;
void reset() final;
static boost::intrusive_ptr<AccumulatorState> create(ExpressionContext* expCtx);
private:
Value _lastNonNull{BSONNULL};
};
} // namespace mongo
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