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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 "mongo/db/matcher/expression_array.h"
#include "mongo/db/matcher/expression_with_placeholder.h"
#include "mongo/stdx/memory.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()
: ArrayMatchingMatchExpression(MatchExpression::INTERNAL_SCHEMA_MATCH_ARRAY_INDEX) {}
Status init(StringData path,
long long index,
std::unique_ptr<ExpressionWithPlaceholder> expression);
void debugString(StringBuilder& debug, int level) 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 = array.begin();
// 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);
}
void serialize(BSONObjBuilder* builder) const final;
std::unique_ptr<MatchExpression> shallowClone() const final;
std::vector<MatchExpression*>* getChildVector() final {
return nullptr;
}
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 {
return [](std::unique_ptr<MatchExpression> expression) { return expression; };
}
long long _index = 0;
std::unique_ptr<ExpressionWithPlaceholder> _expression;
};
} // namespace mongo
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