/
encoder.go
254 lines (223 loc) · 6.39 KB
/
encoder.go
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
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
package json
import (
"bytes"
"encoding/json"
"errors"
"fmt"
"io"
"reflect"
"strconv"
"time"
)
var (
timeType = reflect.TypeOf(time.Time{})
jsonMarshalerType = reflect.TypeOf(new(json.Marshaler)).Elem()
jsonUnmarshalerType = reflect.TypeOf(new(json.Unmarshaler)).Elem()
)
// Marshal marshals the value as JSON, using Amino-compatible JSON encoding (strings for
// 64-bit numbers, and type wrappers for registered types).
func Marshal(v interface{}) ([]byte, error) {
buf := new(bytes.Buffer)
err := encode(buf, v)
if err != nil {
return nil, err
}
return buf.Bytes(), nil
}
// MarshalIndent marshals the value as JSON, using the given prefix and indentation.
func MarshalIndent(v interface{}, prefix, indent string) ([]byte, error) {
bz, err := Marshal(v)
if err != nil {
return nil, err
}
buf := new(bytes.Buffer)
err = json.Indent(buf, bz, prefix, indent)
if err != nil {
return nil, err
}
return buf.Bytes(), nil
}
func encode(w io.Writer, v interface{}) error {
// Bare nil values can't be reflected, so we must handle them here.
if v == nil {
return writeStr(w, "null")
}
rv := reflect.ValueOf(v)
// If this is a registered type, defer to interface encoder regardless of whether the input is
// an interface or a bare value. This retains Amino's behavior, but is inconsistent with
// behavior in structs where an interface field will get the type wrapper while a bare value
// field will not.
if typeRegistry.name(rv.Type()) != "" {
return encodeReflectInterface(w, rv)
}
return encodeReflect(w, rv)
}
func encodeReflect(w io.Writer, rv reflect.Value) error {
if !rv.IsValid() {
return errors.New("invalid reflect value")
}
// Recursively dereference if pointer.
for rv.Kind() == reflect.Ptr {
if rv.IsNil() {
return writeStr(w, "null")
}
rv = rv.Elem()
}
// Convert times to UTC.
if rv.Type() == timeType {
rv = reflect.ValueOf(rv.Interface().(time.Time).Round(0).UTC())
}
// If the value implements json.Marshaler, defer to stdlib directly. Since we've already
// dereferenced, we try implementations with both value receiver and pointer receiver. We must
// do this after the time normalization above, and thus after dereferencing.
if rv.Type().Implements(jsonMarshalerType) {
return encodeStdlib(w, rv.Interface())
} else if rv.CanAddr() && rv.Addr().Type().Implements(jsonMarshalerType) {
return encodeStdlib(w, rv.Addr().Interface())
}
switch rv.Type().Kind() {
// Complex types must be recursively encoded.
case reflect.Interface:
return encodeReflectInterface(w, rv)
case reflect.Array, reflect.Slice:
return encodeReflectList(w, rv)
case reflect.Map:
return encodeReflectMap(w, rv)
case reflect.Struct:
return encodeReflectStruct(w, rv)
// 64-bit integers are emitted as strings, to avoid precision problems with e.g.
// Javascript which uses 64-bit floats (having 53-bit precision).
case reflect.Int64, reflect.Int:
return writeStr(w, `"`+strconv.FormatInt(rv.Int(), 10)+`"`)
case reflect.Uint64, reflect.Uint:
return writeStr(w, `"`+strconv.FormatUint(rv.Uint(), 10)+`"`)
// For everything else, defer to the stdlib encoding/json encoder
default:
return encodeStdlib(w, rv.Interface())
}
}
func encodeReflectList(w io.Writer, rv reflect.Value) error {
// Emit nil slices as null.
if rv.Kind() == reflect.Slice && rv.IsNil() {
return writeStr(w, "null")
}
// Encode byte slices as base64 with the stdlib encoder.
if rv.Type().Elem().Kind() == reflect.Uint8 {
// Stdlib does not base64-encode byte arrays, only slices, so we copy to slice.
if rv.Type().Kind() == reflect.Array {
slice := reflect.MakeSlice(reflect.SliceOf(rv.Type().Elem()), rv.Len(), rv.Len())
reflect.Copy(slice, rv)
rv = slice
}
return encodeStdlib(w, rv.Interface())
}
// Anything else we recursively encode ourselves.
length := rv.Len()
if err := writeStr(w, "["); err != nil {
return err
}
for i := 0; i < length; i++ {
if err := encodeReflect(w, rv.Index(i)); err != nil {
return err
}
if i < length-1 {
if err := writeStr(w, ","); err != nil {
return err
}
}
}
return writeStr(w, "]")
}
func encodeReflectMap(w io.Writer, rv reflect.Value) error {
if rv.Type().Key().Kind() != reflect.String {
return errors.New("map key must be string")
}
// nil maps are not emitted as nil, to retain Amino compatibility.
if err := writeStr(w, "{"); err != nil {
return err
}
writeComma := false
for _, keyrv := range rv.MapKeys() {
if writeComma {
if err := writeStr(w, ","); err != nil {
return err
}
}
if err := encodeStdlib(w, keyrv.Interface()); err != nil {
return err
}
if err := writeStr(w, ":"); err != nil {
return err
}
if err := encodeReflect(w, rv.MapIndex(keyrv)); err != nil {
return err
}
writeComma = true
}
return writeStr(w, "}")
}
func encodeReflectStruct(w io.Writer, rv reflect.Value) error {
sInfo := makeStructInfo(rv.Type())
if err := writeStr(w, "{"); err != nil {
return err
}
writeComma := false
for i, fInfo := range sInfo.fields {
frv := rv.Field(i)
if fInfo.hidden || (fInfo.omitEmpty && frv.IsZero()) {
continue
}
if writeComma {
if err := writeStr(w, ","); err != nil {
return err
}
}
if err := encodeStdlib(w, fInfo.jsonName); err != nil {
return err
}
if err := writeStr(w, ":"); err != nil {
return err
}
if err := encodeReflect(w, frv); err != nil {
return err
}
writeComma = true
}
return writeStr(w, "}")
}
func encodeReflectInterface(w io.Writer, rv reflect.Value) error {
// Get concrete value and dereference pointers.
for rv.Kind() == reflect.Ptr || rv.Kind() == reflect.Interface {
if rv.IsNil() {
return writeStr(w, "null")
}
rv = rv.Elem()
}
// Look up the name of the concrete type
name := typeRegistry.name(rv.Type())
if name == "" {
return fmt.Errorf("cannot encode unregistered type %v", rv.Type())
}
// Write value wrapped in interface envelope
if err := writeStr(w, fmt.Sprintf(`{"type":%q,"value":`, name)); err != nil {
return err
}
if err := encodeReflect(w, rv); err != nil {
return err
}
return writeStr(w, "}")
}
func encodeStdlib(w io.Writer, v interface{}) error {
// Doesn't stream the output because that adds a newline, as per:
// https://golang.org/pkg/encoding/json/#Encoder.Encode
blob, err := json.Marshal(v)
if err != nil {
return err
}
_, err = w.Write(blob)
return err
}
func writeStr(w io.Writer, s string) error {
_, err := w.Write([]byte(s))
return err
}