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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.
*/
#include "mongo/platform/basic.h"
#include "mongo/db/pipeline/accumulator_for_window_functions.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"
namespace mongo {
REGISTER_WINDOW_FUNCTION_CONDITIONALLY(
locf,
mongo::window_function::ExpressionFromLeftUnboundedWindowFunction<AccumulatorLocf>::parse,
multiversion::FeatureCompatibilityVersion::kVersion_5_2,
true);
AccumulatorLocf::AccumulatorLocf(ExpressionContext* const expCtx)
: AccumulatorForWindowFunctions(expCtx) {
_memUsageBytes = sizeof(*this) + _lastNonNull.getApproximateSize();
}
void AccumulatorLocf::processInternal(const Value& input, bool merging) {
tassert(6050100, "$locf can't be merged", !merging);
if (!input.nullish()) {
_lastNonNull = input;
_memUsageBytes = sizeof(*this) + _lastNonNull.getApproximateSize();
}
}
Value AccumulatorLocf::getValue(bool toBeMerged) {
tassert(6050102, "$locf can't be merged", !toBeMerged);
return _lastNonNull;
}
void AccumulatorLocf::reset() {
_lastNonNull = Value(BSONNULL);
_memUsageBytes = sizeof(*this) + _lastNonNull.getApproximateSize();
}
boost::intrusive_ptr<AccumulatorState> AccumulatorLocf::create(ExpressionContext* const expCtx) {
return new AccumulatorLocf(expCtx);
}
} // namespace mongo
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