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/**
* Copyright (C) 2022-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 <map>
#include "mongo/db/exec/sbe/values/value.h"
#include "mongo/db/query/ce/scalar_histogram.h"
namespace mongo::ce {
class ArrayHistogram {
public:
// Constructs an empty scalar histogram.
ArrayHistogram();
// Constructor for scalar field histograms.
ArrayHistogram(ScalarHistogram scalar, std::map<sbe::value::TypeTags, size_t> typeCounts);
// Constructor for array field histograms. We have to initialize all array fields in this case.
ArrayHistogram(ScalarHistogram scalar,
std::map<sbe::value::TypeTags, size_t> typeCounts,
ScalarHistogram arrayUnique,
ScalarHistogram arrayMin,
ScalarHistogram arrayMax,
std::map<sbe::value::TypeTags, size_t> arrayTypeCounts);
// ArrayHistogram is neither copy-constructible nor copy-assignable.
ArrayHistogram(const ArrayHistogram&) = delete;
ArrayHistogram& operator=(const ArrayHistogram&) = delete;
// However, it is move-constructible and move-assignable.
ArrayHistogram(ArrayHistogram&&) = default;
ArrayHistogram& operator=(ArrayHistogram&&) = default;
~ArrayHistogram() = default;
// Returns whether or not this histogram includes array data points.
bool isArray() const;
std::string toString() const;
const ScalarHistogram& getScalar() const;
const ScalarHistogram& getArrayUnique() const;
const ScalarHistogram& getArrayMin() const;
const ScalarHistogram& getArrayMax() const;
const std::map<sbe::value::TypeTags, size_t>& getTypeCounts() const;
const std::map<sbe::value::TypeTags, size_t>& getArrayTypeCounts() const;
private:
/* ScalarHistogram fields for all paths. */
// Contains values which appeared originally as scalars on the path.
ScalarHistogram _scalar;
std::map<sbe::value::TypeTags, size_t> _typeCounts;
/* ScalarHistogram fields for array paths (only initialized if arrays are present). */
// Contains unique scalar values originating from arrays.
boost::optional<ScalarHistogram> _arrayUnique;
// Contains minimum values originating from arrays **per class**.
boost::optional<ScalarHistogram> _arrayMin;
// Contains maximum values originating from arrays **per class**.
boost::optional<ScalarHistogram> _arrayMax;
boost::optional<std::map<sbe::value::TypeTags, size_t>> _arrayTypeCounts;
};
} // namespace mongo::ce
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