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
|
// Copyright 2015 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package gensupport
import (
"encoding/json"
"fmt"
"reflect"
"strings"
)
// MarshalJSON returns a JSON encoding of schema containing only selected fields.
// A field is selected if any of the following is true:
// * it has a non-empty value
// * its field name is present in forceSendFields and it is not a nil pointer or nil interface
// * its field name is present in nullFields.
// The JSON key for each selected field is taken from the field's json: struct tag.
func MarshalJSON(schema interface{}, forceSendFields, nullFields []string) ([]byte, error) {
if len(forceSendFields) == 0 && len(nullFields) == 0 {
return json.Marshal(schema)
}
mustInclude := make(map[string]struct{})
for _, f := range forceSendFields {
mustInclude[f] = struct{}{}
}
useNull := make(map[string]struct{})
for _, f := range nullFields {
useNull[f] = struct{}{}
}
dataMap, err := schemaToMap(schema, mustInclude, useNull)
if err != nil {
return nil, err
}
return json.Marshal(dataMap)
}
func schemaToMap(schema interface{}, mustInclude, useNull map[string]struct{}) (map[string]interface{}, error) {
m := make(map[string]interface{})
s := reflect.ValueOf(schema)
st := s.Type()
for i := 0; i < s.NumField(); i++ {
jsonTag := st.Field(i).Tag.Get("json")
if jsonTag == "" {
continue
}
tag, err := parseJSONTag(jsonTag)
if err != nil {
return nil, err
}
if tag.ignore {
continue
}
v := s.Field(i)
f := st.Field(i)
if _, ok := useNull[f.Name]; ok {
if !isEmptyValue(v) {
return nil, fmt.Errorf("field %q in NullFields has non-empty value", f.Name)
}
m[tag.apiName] = nil
continue
}
if !includeField(v, f, mustInclude) {
continue
}
// nil maps are treated as empty maps.
if f.Type.Kind() == reflect.Map && v.IsNil() {
m[tag.apiName] = map[string]string{}
continue
}
// nil slices are treated as empty slices.
if f.Type.Kind() == reflect.Slice && v.IsNil() {
m[tag.apiName] = []bool{}
continue
}
if tag.stringFormat {
m[tag.apiName] = formatAsString(v, f.Type.Kind())
} else {
m[tag.apiName] = v.Interface()
}
}
return m, nil
}
// formatAsString returns a string representation of v, dereferencing it first if possible.
func formatAsString(v reflect.Value, kind reflect.Kind) string {
if kind == reflect.Ptr && !v.IsNil() {
v = v.Elem()
}
return fmt.Sprintf("%v", v.Interface())
}
// jsonTag represents a restricted version of the struct tag format used by encoding/json.
// It is used to describe the JSON encoding of fields in a Schema struct.
type jsonTag struct {
apiName string
stringFormat bool
ignore bool
}
// parseJSONTag parses a restricted version of the struct tag format used by encoding/json.
// The format of the tag must match that generated by the Schema.writeSchemaStruct method
// in the api generator.
func parseJSONTag(val string) (jsonTag, error) {
if val == "-" {
return jsonTag{ignore: true}, nil
}
var tag jsonTag
i := strings.Index(val, ",")
if i == -1 || val[:i] == "" {
return tag, fmt.Errorf("malformed json tag: %s", val)
}
tag = jsonTag{
apiName: val[:i],
}
switch val[i+1:] {
case "omitempty":
case "omitempty,string":
tag.stringFormat = true
default:
return tag, fmt.Errorf("malformed json tag: %s", val)
}
return tag, nil
}
// Reports whether the struct field "f" with value "v" should be included in JSON output.
func includeField(v reflect.Value, f reflect.StructField, mustInclude map[string]struct{}) bool {
// The regular JSON encoding of a nil pointer is "null", which means "delete this field".
// Therefore, we could enable field deletion by honoring pointer fields' presence in the mustInclude set.
// However, many fields are not pointers, so there would be no way to delete these fields.
// Rather than partially supporting field deletion, we ignore mustInclude for nil pointer fields.
// Deletion will be handled by a separate mechanism.
if f.Type.Kind() == reflect.Ptr && v.IsNil() {
return false
}
// The "any" type is represented as an interface{}. If this interface
// is nil, there is no reasonable representation to send. We ignore
// these fields, for the same reasons as given above for pointers.
if f.Type.Kind() == reflect.Interface && v.IsNil() {
return false
}
_, ok := mustInclude[f.Name]
return ok || !isEmptyValue(v)
}
// isEmptyValue reports whether v is the empty value for its type. This
// implementation is based on that of the encoding/json package, but its
// correctness does not depend on it being identical. What's important is that
// this function return false in situations where v should not be sent as part
// of a PATCH operation.
func isEmptyValue(v reflect.Value) bool {
switch v.Kind() {
case reflect.Array, reflect.Map, reflect.Slice, reflect.String:
return v.Len() == 0
case reflect.Bool:
return !v.Bool()
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
return v.Int() == 0
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
return v.Uint() == 0
case reflect.Float32, reflect.Float64:
return v.Float() == 0
case reflect.Interface, reflect.Ptr:
return v.IsNil()
}
return false
}
|
