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/**
* Copyright (C) 2018-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.
*/
#include "mongo/platform/basic.h"
#include "mongo/db/pipeline/accumulator.h"
#include "mongo/db/exec/document_value/value.h"
#include "mongo/db/pipeline/accumulation_statement.h"
#include "mongo/db/pipeline/expression.h"
#include "mongo/db/pipeline/window_function/window_function_expression.h"
#include "mongo/db/pipeline/window_function/window_function_min_max.h"
namespace mongo {
using boost::intrusive_ptr;
REGISTER_ACCUMULATOR(max, genericParseSingleExpressionAccumulator<AccumulatorMax>);
REGISTER_ACCUMULATOR(min, genericParseSingleExpressionAccumulator<AccumulatorMin>);
REGISTER_STABLE_EXPRESSION(max, ExpressionFromAccumulator<AccumulatorMax>::parse);
REGISTER_STABLE_EXPRESSION(min, ExpressionFromAccumulator<AccumulatorMin>::parse);
REGISTER_STABLE_REMOVABLE_WINDOW_FUNCTION(max, AccumulatorMax, WindowFunctionMax);
REGISTER_STABLE_REMOVABLE_WINDOW_FUNCTION(min, AccumulatorMin, WindowFunctionMin);
void AccumulatorMinMax::processInternal(const Value& input, bool merging) {
// nullish values should have no impact on result
if (!input.nullish()) {
/* compare with the current value; swap if appropriate */
int cmp = getExpressionContext()->getValueComparator().compare(_val, input) * _sense;
if (cmp > 0 || _val.missing()) { // missing is lower than all other values
_val = input;
_memUsageBytes = sizeof(*this) + input.getApproximateSize() - sizeof(Value);
}
}
}
Value AccumulatorMinMax::getValue(bool toBeMerged) {
if (_val.missing()) {
return Value(BSONNULL);
}
return _val;
}
AccumulatorMinMax::AccumulatorMinMax(ExpressionContext* const expCtx, Sense sense)
: AccumulatorState(expCtx), _sense(sense) {
_memUsageBytes = sizeof(*this);
}
void AccumulatorMinMax::reset() {
_val = Value();
_memUsageBytes = sizeof(*this);
}
intrusive_ptr<AccumulatorState> AccumulatorMin::create(ExpressionContext* const expCtx) {
return new AccumulatorMin(expCtx);
}
intrusive_ptr<AccumulatorState> AccumulatorMax::create(ExpressionContext* const expCtx) {
return new AccumulatorMax(expCtx);
}
} // namespace mongo
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