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
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
|
/**
* 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 "mongo/util/assert_util.h"
#include "mongo/util/overloaded_visitor.h"
#include <boost/optional.hpp>
#include "mongo/base/string_data.h"
#include "mongo/bson/bsonobj.h"
#include "mongo/bson/bsonobjbuilder.h"
#include "mongo/stdx/variant.h"
using namespace fmt::literals;
namespace mongo {
/**
* Wraps a boost::optional<bool> to provide consistent semantics. A standard boost::optional<bool>
* can introduce ambiguity because its 'operator bool' will resolve to 'true' if the optional is
* populated, even if is populated with boolean 'false'. By contrast, an instance of this class
* always resolves to the populated value, or false if not yet populated. This class will also
* serialize to BSON via the IDL only if the value has been explicitly set.
*/
class OptionalBool {
public:
/**
* IMPORTANT: The method should not be modified, as API version input/output guarantees could
* break because of it.
*/
static OptionalBool parseFromBSON(BSONElement element) {
uassert(ErrorCodes::TypeMismatch,
str::stream() << "Field '" << element.fieldNameStringData()
<< "' should be a boolean value, but found: " << element.type(),
!element || element.type() == BSONType::Bool);
return element ? OptionalBool{element.boolean()} : OptionalBool{};
}
OptionalBool(boost::optional<bool> value) : _value(std::move(value)) {}
OptionalBool(bool value) : _value(value) {}
OptionalBool() : OptionalBool(boost::none) {}
/**
* Returns true only if _value is populated with a value of true.
*/
operator bool() const {
return _value.value_or(false);
}
/**
* Returns the stored value or the given defaultValue if nothing is stored.
*/
bool value_or(bool defaultValue) const {
return _value.value_or(defaultValue);
}
/**
* Returns true if the value has been populated, false otherwise.
*/
bool has_value() const {
return _value.has_value();
}
/**
* Serialize this object as a field in a document. If _value is empty, omit the field.
*
* IMPORTANT: The method should not be modified, as API version input/output guarantees could
* break because of it.
*/
void serializeToBSON(StringData fieldName, BSONObjBuilder* builder) const {
if (_value) {
builder->appendBool(fieldName, *_value);
}
}
/**
* Serialize this object as an element of a BSON array. If _value is empty, omit the entry.
*
* IMPORTANT: The method should not be modified, as API version input/output guarantees could
* break because of it.
*/
void serializeToBSON(BSONArrayBuilder* builder) const {
if (_value) {
builder->append(*_value);
}
}
/**
* Returns a string representation of the current value.
*/
std::string toString() const {
return *this ? "1" : "0";
}
operator std::string() const {
return toString();
}
private:
boost::optional<bool> _value;
};
/**
* Class to represent a BSON element with any type from IDL. The caller must ensure that the backing
* BSON stays alive while this type is in use.
*/
class IDLAnyType {
public:
/**
* IMPORTANT: The method should not be modified, as API version input/output guarantees could
* break because of it.
*/
static IDLAnyType parseFromBSON(const BSONElement& element) {
return IDLAnyType(element);
}
IDLAnyType() = default;
IDLAnyType(const BSONElement& element) : _element(element) {}
/**
* IMPORTANT: The method should not be modified, as API version input/output guarantees could
* break because of it.
*/
void serializeToBSON(StringData fieldName, BSONObjBuilder* builder) const {
builder->appendAs(_element, fieldName);
}
/**
* IMPORTANT: The method should not be modified, as API version input/output guarantees could
* break because of it.
*/
void serializeToBSON(BSONArrayBuilder* builder) const {
builder->append(_element);
}
const BSONElement& getElement() const {
return _element;
}
protected:
BSONElement _element;
};
/**
* Class to represent a BSON element with any type from IDL. Unlike IDLAnyType, here the caller
* does not need to ensure the backing BSON stays alive; it is handled by the class.
*/
class IDLAnyTypeOwned : public IDLAnyType {
public:
/**
* IMPORTANT: The method should not be modified, as API version input/output guarantees could
* break because of it.
*/
static IDLAnyTypeOwned parseFromBSON(const BSONElement& element) {
return IDLAnyTypeOwned(element);
}
IDLAnyTypeOwned() = default;
IDLAnyTypeOwned(const BSONElement& element) {
_obj = element.wrap();
_element = _obj.firstElement();
}
// This constructor can be used to avoid copying the contents of 'element'.
IDLAnyTypeOwned(const BSONElement& element, BSONObj owningBSONObj)
: IDLAnyType(element), _obj(std::move(owningBSONObj)) {}
private:
BSONObj _obj;
};
} // namespace mongo
|
