fermentord/vendor/github.com/mitchellh/mapstructure/decode_hooks.go

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package mapstructure
import (
"encoding"
"errors"
"fmt"
"net"
"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
var f3 DecodeHookFuncValue
// Fill in the variables into this interface and the rest is done
// automatically using the reflect package.
potential := []interface{}{f1, f2, f3}
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.Value, to reflect.Value) (interface{}, error) {
switch f := typedDecodeHook(raw).(type) {
case DecodeHookFuncType:
return f(from.Type(), to.Type(), from.Interface())
case DecodeHookFuncKind:
return f(from.Kind(), to.Kind(), from.Interface())
case DecodeHookFuncValue:
return f(from, to)
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.Value, t reflect.Value) (interface{}, error) {
var err error
data := f.Interface()
newFrom := f
for _, f1 := range fs {
data, err = DecodeHookExec(f1, newFrom, t)
if err != nil {
return nil, err
}
newFrom = reflect.ValueOf(data)
}
return data, nil
}
}
// OrComposeDecodeHookFunc executes all input hook functions until one of them returns no error. In that case its value is returned.
// If all hooks return an error, OrComposeDecodeHookFunc returns an error concatenating all error messages.
func OrComposeDecodeHookFunc(ff ...DecodeHookFunc) DecodeHookFunc {
return func(a, b reflect.Value) (interface{}, error) {
var allErrs string
var out interface{}
var err error
for _, f := range ff {
out, err = DecodeHookExec(f, a, b)
if err != nil {
allErrs += err.Error() + "\n"
continue
}
return out, nil
}
return nil, errors.New(allErrs)
}
}
// 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))
}
}
// StringToIPHookFunc returns a DecodeHookFunc that converts
// strings to net.IP
func StringToIPHookFunc() 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(net.IP{}) {
return data, nil
}
// Convert it by parsing
ip := net.ParseIP(data.(string))
if ip == nil {
return net.IP{}, fmt.Errorf("failed parsing ip %v", data)
}
return ip, nil
}
}
// StringToIPNetHookFunc returns a DecodeHookFunc that converts
// strings to net.IPNet
func StringToIPNetHookFunc() 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(net.IPNet{}) {
return data, nil
}
// Convert it by parsing
_, net, err := net.ParseCIDR(data.(string))
return net, err
}
}
// StringToTimeHookFunc returns a DecodeHookFunc that converts
// strings to time.Time.
func StringToTimeHookFunc(layout string) 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.Time{}) {
return data, nil
}
// Convert it by parsing
return time.Parse(layout, data.(string))
}
}
// WeaklyTypedHook is a DecodeHookFunc which adds support for weak typing to
// the decoder.
//
// Note that this is significantly different from the WeaklyTypedInput option
// of the DecoderConfig.
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
}
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
}
func RecursiveStructToMapHookFunc() DecodeHookFunc {
return func(f reflect.Value, t reflect.Value) (interface{}, error) {
if f.Kind() != reflect.Struct {
return f.Interface(), nil
}
var i interface{} = struct{}{}
if t.Type() != reflect.TypeOf(&i).Elem() {
return f.Interface(), nil
}
m := make(map[string]interface{})
t.Set(reflect.ValueOf(m))
return f.Interface(), nil
}
}
// TextUnmarshallerHookFunc returns a DecodeHookFunc that applies
// strings to the UnmarshalText function, when the target type
// implements the encoding.TextUnmarshaler interface
func TextUnmarshallerHookFunc() DecodeHookFuncType {
return func(
f reflect.Type,
t reflect.Type,
data interface{}) (interface{}, error) {
if f.Kind() != reflect.String {
return data, nil
}
result := reflect.New(t).Interface()
unmarshaller, ok := result.(encoding.TextUnmarshaler)
if !ok {
return data, nil
}
if err := unmarshaller.UnmarshalText([]byte(data.(string))); err != nil {
return nil, err
}
return result, nil
}
}