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
|
/**
* Copyright (c) 2014 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 <boost/optional.hpp>
#include <set>
#include <string>
#include "mongo/db/pipeline/document.h"
namespace mongo {
class ParsedDeps;
/**
* This struct allows components in an agg pipeline to report what they need from their input.
*/
struct DepsTracker {
/**
* Represents what metadata is available on documents that are input to the pipeline.
*/
enum MetadataAvailable { kNoMetadata = 0, kTextScore = 1 };
DepsTracker(MetadataAvailable metadataAvailable = kNoMetadata)
: needWholeDocument(false), _metadataAvailable(metadataAvailable), _needTextScore(false) {}
/**
* Returns a projection object covering the dependencies tracked by this class.
*/
BSONObj toProjection() const;
boost::optional<ParsedDeps> toParsedDeps() const;
std::set<std::string> fields; // names of needed fields in dotted notation
bool needWholeDocument; // if true, ignore fields and assume the whole document is needed
bool hasNoRequirements() const {
return fields.empty() && !needWholeDocument && !_needTextScore;
}
MetadataAvailable getMetadataAvailable() const {
return _metadataAvailable;
}
bool isTextScoreAvailable() const {
return _metadataAvailable & MetadataAvailable::kTextScore;
}
bool getNeedTextScore() const {
return _needTextScore;
}
void setNeedTextScore(bool needTextScore) {
if (needTextScore && !isTextScoreAvailable()) {
uasserted(
40218,
"pipeline requires text score metadata, but there is no text score available");
}
_needTextScore = needTextScore;
}
private:
MetadataAvailable _metadataAvailable;
bool _needTextScore;
};
/**
* This class is designed to quickly extract the needed fields from a BSONObj into a Document.
* It should only be created by a call to DepsTracker::ParsedDeps
*/
class ParsedDeps {
public:
Document extractFields(const BSONObj& input) const;
private:
friend struct DepsTracker; // so it can call constructor
explicit ParsedDeps(const Document& fields) : _fields(fields) {}
Document _fields;
};
}
|
