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
|
package mapstructure
import (
"errors"
"reflect"
"strconv"
"strings"
"time"
)
// typedDecodeHook takes a raw DecodeHookFunc (an interface{}) and turns
// it into the proper DecodeHookFunc type, such as DecodeHookFuncType.
func typedDecodeHook(h DecodeHookFunc) DecodeHookFunc {
// Create variables here so we can reference them with the reflect pkg
var f1 DecodeHookFuncType
var f2 DecodeHookFuncKind
// Fill in the variables into this interface and the rest is done
// automatically using the reflect package.
potential := []interface{}{f1, f2}
v := reflect.ValueOf(h)
vt := v.Type()
for _, raw := range potential {
pt := reflect.ValueOf(raw).Type()
if vt.ConvertibleTo(pt) {
return v.Convert(pt).Interface()
}
}
return nil
}
// DecodeHookExec executes the given decode hook. This should be used
// since it'll naturally degrade to the older backwards compatible DecodeHookFunc
// that took reflect.Kind instead of reflect.Type.
func DecodeHookExec(
raw DecodeHookFunc,
from reflect.Type, to reflect.Type,
data interface{}) (interface{}, error) {
// Build our arguments that reflect expects
argVals := make([]reflect.Value, 3)
argVals[0] = reflect.ValueOf(from)
argVals[1] = reflect.ValueOf(to)
argVals[2] = reflect.ValueOf(data)
switch f := typedDecodeHook(raw).(type) {
case DecodeHookFuncType:
return f(from, to, data)
case DecodeHookFuncKind:
return f(from.Kind(), to.Kind(), data)
default:
return nil, errors.New("invalid decode hook signature")
}
}
// ComposeDecodeHookFunc creates a single DecodeHookFunc that
// automatically composes multiple DecodeHookFuncs.
//
// The composed funcs are called in order, with the result of the
// previous transformation.
func ComposeDecodeHookFunc(fs ...DecodeHookFunc) DecodeHookFunc {
return func(
f reflect.Type,
t reflect.Type,
data interface{}) (interface{}, error) {
var err error
for _, f1 := range fs {
data, err = DecodeHookExec(f1, f, t, data)
if err != nil {
return nil, err
}
// Modify the from kind to be correct with the new data
f = nil
if val := reflect.ValueOf(data); val.IsValid() {
f = val.Type()
}
}
return data, nil
}
}
// StringToSliceHookFunc returns a DecodeHookFunc that converts
// string to []string by splitting on the given sep.
func StringToSliceHookFunc(sep string) DecodeHookFunc {
return func(
f reflect.Kind,
t reflect.Kind,
data interface{}) (interface{}, error) {
if f != reflect.String || t != reflect.Slice {
return data, nil
}
raw := data.(string)
if raw == "" {
return []string{}, nil
}
return strings.Split(raw, sep), nil
}
}
// StringToTimeDurationHookFunc returns a DecodeHookFunc that converts
// strings to time.Duration.
func StringToTimeDurationHookFunc() DecodeHookFunc {
return func(
f reflect.Type,
t reflect.Type,
data interface{}) (interface{}, error) {
if f.Kind() != reflect.String {
return data, nil
}
if t != reflect.TypeOf(time.Duration(5)) {
return data, nil
}
// Convert it by parsing
return time.ParseDuration(data.(string))
}
}
func WeaklyTypedHook(
f reflect.Kind,
t reflect.Kind,
data interface{}) (interface{}, error) {
dataVal := reflect.ValueOf(data)
switch t {
case reflect.String:
switch f {
case reflect.Bool:
if dataVal.Bool() {
return "1", nil
} else {
return "0", nil
}
case reflect.Float32:
return strconv.FormatFloat(dataVal.Float(), 'f', -1, 64), nil
case reflect.Int:
return strconv.FormatInt(dataVal.Int(), 10), nil
case reflect.Slice:
dataType := dataVal.Type()
elemKind := dataType.Elem().Kind()
if elemKind == reflect.Uint8 {
return string(dataVal.Interface().([]uint8)), nil
}
case reflect.Uint:
return strconv.FormatUint(dataVal.Uint(), 10), nil
}
}
return data, nil
}
|
