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
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
|
/**
* Copyright (C) 2018-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 <memory>
#include "mongo/db/pipeline/expression.h"
#include "mongo/db/pipeline/expression_context.h"
#include "mongo/db/pipeline/parsed_aggregation_projection.h"
#include "mongo/db/pipeline/parsed_inclusion_projection.h"
#include "mongo/stdx/memory.h"
namespace mongo {
namespace parsed_aggregation_projection {
/**
* A ParsedAddFields represents a parsed form of the raw BSON specification for the AddFields
* stage.
*
* This class is mostly a wrapper around an InclusionNode tree. It contains logic to parse a
* specification object into the corresponding InclusionNode tree, but defers most execution logic
* to the underlying tree. In this way it is similar to ParsedInclusionProjection, but it differs
* by not applying inclusions before adding computed fields, thus keeping all existing fields.
*/
class ParsedAddFields : public ParsedAggregationProjection {
public:
/**
* TODO SERVER-25510: The ParsedAggregationProjection _id and array-recursion policies are not
* applicable to the $addFields "projection" stage. We make them non-configurable here.
*/
ParsedAddFields(const boost::intrusive_ptr<ExpressionContext>& expCtx)
: ParsedAggregationProjection(expCtx,
ProjectionDefaultIdPolicy::kIncludeId,
ProjectionArrayRecursionPolicy::kRecurseNestedArrays),
_root(new InclusionNode(_arrayRecursionPolicy)) {}
/**
* Creates the data needed to perform an AddFields.
* Verifies that there are no conflicting paths in the specification.
* Overrides the ParsedAggregationProjection's create method.
*/
static std::unique_ptr<ParsedAddFields> create(
const boost::intrusive_ptr<ExpressionContext>& expCtx, const BSONObj& spec);
TransformerType getType() const final {
return TransformerType::kComputedProjection;
}
/**
* Parses the addFields specification given by 'spec', populating internal data structures.
*/
void parse(const BSONObj& spec) final;
Document serializeTransformation(
boost::optional<ExplainOptions::Verbosity> explain) const final {
MutableDocument output;
_root->serialize(&output, explain);
return output.freeze();
}
/**
* Optimizes any computed expressions.
*/
void optimize() final {
_root->optimize();
}
DepsTracker::State addDependencies(DepsTracker* deps) const final {
_root->addDependencies(deps);
return DepsTracker::State::SEE_NEXT;
}
DocumentSource::GetModPathsReturn getModifiedPaths() const final {
std::set<std::string> computedPaths;
StringMap<std::string> renamedPaths;
_root->addComputedPaths(&computedPaths, &renamedPaths);
return {DocumentSource::GetModPathsReturn::Type::kFiniteSet,
std::move(computedPaths),
std::move(renamedPaths)};
}
/**
* Add the specified fields to 'inputDoc'.
*
* Replaced fields will remain in their original place in the document, while new added fields
* will be added to the end of the document in the order in which they were specified to the
* $addFields stage.
*
* Arrays will be traversed, with any dotted/nested computed fields applied to each element in
* the array. For example, setting "a.0": "hello" will add a field "0" to every object
* in the array "a". If there is an element in "a" that is not an object, it will be replaced
* with {"0": "hello"}. See SERVER-25200 for more details.
*/
Document applyProjection(const Document& inputDoc) const final;
private:
/**
* Attempts to parse 'objSpec' as an expression like {$add: [...]}. Adds a computed field to
* '_root' and returns true if it was successfully parsed as an expression. Returns false if it
* was not an expression specification.
*
* Throws an error if it was determined to be an expression specification, but failed to parse
* as a valid expression.
*/
bool parseObjectAsExpression(StringData pathToObject,
const BSONObj& objSpec,
const VariablesParseState& variablesParseState);
/**
* Traverses 'subObj' and parses each field. Adds any computed fields at this level
* to 'node'.
*/
void parseSubObject(const BSONObj& subObj,
const VariablesParseState& variablesParseState,
InclusionNode* node);
// The InclusionNode tree does most of the execution work once constructed.
std::unique_ptr<InclusionNode> _root;
};
} // namespace parsed_aggregation_projection
} // namespace mongo
|