1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
|
/**
* 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"
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;
};
SortPattern(const BSONObj&, const boost::intrusive_ptr<ExpressionContext>&);
/**
* Write out a Document whose contents are the sort key pattern.
*/
Document serialize(SortKeySerialization) 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();
}
/**
* 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 a 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];
}
std::vector<SortPatternPart>::const_iterator begin() const {
return _sortPattern.cbegin();
}
std::vector<SortPatternPart>::const_iterator end() const {
return _sortPattern.cend();
}
/**
* 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.
std::set<std::string> _paths;
};
} // namespace mongo
|
