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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.
*/
#include "mongo/platform/basic.h"
#include "mongo/db/pipeline/accumulation_statement.h"
#include "mongo/db/pipeline/document_source_add_fields.h"
#include "mongo/db/pipeline/document_source_project.h"
#include "mongo/db/pipeline/document_source_set_window_fields.h"
#include "mongo/db/pipeline/document_source_set_window_fields_gen.h"
#include "mongo/db/pipeline/lite_parsed_document_source.h"
#include "mongo/db/query/query_feature_flags_gen.h"
#include "mongo/db/pipeline/window_function_expression.h"
using boost::intrusive_ptr;
using boost::optional;
namespace mongo::window_function {
StringMap<Expression::Parser> Expression::parserMap;
intrusive_ptr<Expression> Expression::parse(BSONElement elem,
const optional<SortPattern>& sortBy,
ExpressionContext* expCtx) {
auto parser = parserMap.find(elem.fieldNameStringData());
uassert(ErrorCodes::FailedToParse,
str::stream() << "No such window function: " << elem.fieldName(),
parser != parserMap.end());
uassert(ErrorCodes::FailedToParse,
str::stream() << "Window function " << elem.fieldName() << " requires an object.",
elem.type() == BSONType::Object);
return parser->second(elem, sortBy, expCtx);
}
void Expression::registerParser(std::string functionName, Parser parser) {
invariant(parserMap.find(functionName) == parserMap.end());
parserMap.emplace(std::move(functionName), std::move(parser));
}
MONGO_INITIALIZER(windowFunctionExpressionMap)(InitializerContext*) {
// Nothing to do. This initializer exists to tie together all the individual initializers
// defined by REGISTER_WINDOW_FUNCTION.
}
} // namespace mongo::window_function
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