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/**
* Copyright (C) 2019-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 <vector>
#include "mongo/db/exec/document_value/document.h"
#include "mongo/db/pipeline/document_path_support.h"
#include "mongo/db/pipeline/expression.h"
#include "mongo/db/query/serialization_options.h"
namespace mongo {
class SortPattern {
public:
enum class SortKeySerialization {
kForExplain,
kForPipelineSerialization,
kForSortKeyMerging,
};
// Represents one of the components in a compound sort pattern. Each component is either the
// field path by which we are sorting, or an Expression which can be used to retrieve the sort
// value in the case of a $meta-sort (but not both).
struct SortPatternPart {
bool isAscending = true;
boost::optional<FieldPath> fieldPath;
boost::intrusive_ptr<ExpressionMeta> expression;
bool operator==(const SortPatternPart& other) const {
return isAscending == other.isAscending && fieldPath == other.fieldPath &&
expression == other.expression;
}
bool operator!=(const SortPatternPart& other) const {
return !(*this == other);
}
};
SortPattern(const BSONObj&, const boost::intrusive_ptr<ExpressionContext>&);
SortPattern(std::vector<SortPatternPart> patterns) : _sortPattern(std::move(patterns)) {
for (auto&& patternPart : _sortPattern) {
if (patternPart.fieldPath) {
const auto [_, inserted] = _paths.insert(patternPart.fieldPath->fullPath());
uassert(7472501,
str::stream() << "$sort key must not contain duplicate keys (field: '"
<< patternPart.fieldPath->fullPath() << "')",
inserted);
}
}
}
/**
* Write out a Document whose contents are the sort key pattern.
*/
Document serialize(SortKeySerialization serializationMode,
SerializationOptions options = {}) const;
/**
* Serializes the document to BSON, only keeping the paths specified in the sort pattern.
*/
BSONObj documentToBsonWithSortPaths(const Document& doc) const {
return document_path_support::documentToBsonWithPaths(doc, _paths);
}
size_t size() const {
return _sortPattern.size();
}
bool empty() const {
return _sortPattern.empty();
}
void addDependencies(DepsTracker* deps) const;
/**
* Singleton sort patterns are a special case. In memory, sort keys for singleton patterns get
* stored as a single Value, corresponding to the single component of the sort pattern. By
* contrast, sort patterns for "compound" sort keys get stored as a Value that is an array,
* with one element for each component of the sort.
*/
bool isSingleElementKey() const {
return _sortPattern.size() == 1;
}
const SortPatternPart& operator[](int idx) const {
return _sortPattern[idx];
}
/**
* Returns true if this SortPattern is an extension of the other.
*/
bool isExtensionOf(const SortPattern& other) const;
bool operator==(const SortPattern& other) const {
return _sortPattern == other._sortPattern && _paths == other._paths;
}
bool operator!=(const SortPattern& other) const {
return !(*this == other);
}
std::vector<SortPatternPart>::const_iterator begin() const {
return _sortPattern.cbegin();
}
std::vector<SortPatternPart>::const_iterator end() const {
return _sortPattern.cend();
}
SortPatternPart front() const {
return _sortPattern.front();
}
SortPatternPart back() const {
return _sortPattern.back();
}
/**
* Returns the types of metadata depended on by this sort.
*
* The caller can optionally supply a description of the types of metadata that are not
* available. In this case, throws a UserException if any unavailable metadata type is also a
* metadata dependency.
*/
QueryMetadataBitSet metadataDeps(
QueryMetadataBitSet unavailableMetadata = QueryMetadataBitSet{}) const;
private:
std::vector<SortPatternPart> _sortPattern;
// The set of paths on which we're sorting.
OrderedPathSet _paths;
};
} // namespace mongo
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