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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.
*/
#pragma once
#include <boost/optional.hpp>
#include <memory>
#include "mongo/db/matcher/expression_array.h"
#include "mongo/db/matcher/expression_with_placeholder.h"
namespace mongo {
/**
* Matches arrays based on whether or not a specific element in the array matches a sub-expression.
*/
class InternalSchemaMatchArrayIndexMatchExpression final : public ArrayMatchingMatchExpression {
public:
static constexpr StringData kName = "$_internalSchemaMatchArrayIndex"_sd;
InternalSchemaMatchArrayIndexMatchExpression(
StringData path, long long index, std::unique_ptr<ExpressionWithPlaceholder> expression);
void debugString(StringBuilder& debug, int indentationLevel) const final;
bool equivalent(const MatchExpression* expr) const final;
/**
* Matches 'array' if the element at '_index' matches '_expression', or if its size is less than
* '_index'.
*/
bool matchesArray(const BSONObj& array, MatchDetails* details) const final {
BSONElement element;
auto iterator = BSONObjIterator(array);
// Skip ahead to the element we want, bailing early if there aren't enough elements.
for (auto i = 0LL; i <= _index; ++i) {
if (!iterator.more()) {
return true;
}
element = iterator.next();
}
return _expression->matchesBSONElement(element, details);
}
BSONObj getSerializedRightHandSide() const final;
std::unique_ptr<MatchExpression> shallowClone() const final;
boost::optional<std::vector<MatchExpression*>&> getChildVector() final {
return boost::none;
}
size_t numChildren() const final {
return 1;
}
MatchExpression* getChild(size_t i) const final {
invariant(i == 0);
return _expression->getFilter();
}
private:
ExpressionOptimizerFunc getOptimizer() const final;
long long _index = 0;
std::unique_ptr<ExpressionWithPlaceholder> _expression;
};
} // namespace mongo
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