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/**
* Copyright (C) 2017 MongoDB Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* 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
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* 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 GNU Affero General 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 <regex>
#include "mongo/db/matcher/expression_parser.h"
namespace mongo {
/**
* Container for a parsed MatchExpression and top-level field name that it's over.
* For example, {"i.a": 0, "i.b": 1} is a filter with a single top-level field name "i".
*/
class ExpressionWithPlaceholder {
public:
static const std::regex placeholderRegex;
/**
* Parses 'rawFilter' to an ExpressionWithPlaceholder. This succeeds if 'rawFilter' is a
* filter over a single top-level field, which begins with a lowercase letter and contains
* no special characters. Otherwise, a non-OK status is returned. Callers must maintain
* ownership of 'rawFilter'.
*/
static StatusWith<std::unique_ptr<ExpressionWithPlaceholder>> parse(
BSONObj rawFilter, const CollatorInterface* collator);
/**
* Construct a new ExpressionWithPlaceholder. 'filter' must point to a valid MatchExpression.
*/
ExpressionWithPlaceholder(std::string placeholder, std::unique_ptr<MatchExpression> filter)
: _placeholder(std::move(placeholder)), _filter(std::move(filter)) {
invariant(static_cast<bool>(_filter));
}
/**
* Returns true if this expression has both a placeholder and filter
* equivalent to 'other'.
*/
bool equivalent(const ExpressionWithPlaceholder* other) const;
StringData getPlaceholder() const {
return _placeholder;
}
MatchExpression* getFilter() const {
return _filter.get();
}
private:
// The top-level field that _filter is over.
const std::string _placeholder;
const std::unique_ptr<MatchExpression> _filter;
};
} // namespace mongo
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