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type_clone.go
type_clone.go 1.65 KiB
package reflection
import (
"reflect"
"strings"
"gitlab.com/uafrica/go-utils/errors"
)
func CloneType(t reflect.Type, replace map[string]reflect.Type) (reflect.Type, error) {
return clone("", t, replace)
}
func clone(name string, t reflect.Type, replace map[string]reflect.Type) (reflect.Type, error) {
switch t.Kind() {
case reflect.Struct:
fields := []reflect.StructField{}
for i := 0; i < t.NumField(); i++ {
f := t.Field(i)
n := strings.SplitN(f.Tag.Get("json"), ",", 2)[0] //exclude ,omitempty...
if n == "" {
n = f.Name
}
fieldName := name + "." + n
for replaceName, replaceType := range replace {
if strings.HasPrefix(replaceName, fieldName) {
if replaceName == fieldName {
f.Type = replaceType
} else {
clonedType, err := clone(fieldName, f.Type, replace)
if err != nil {
return t, errors.Wrapf(err, "failed to clone %s", fieldName)
}
f.Type = clonedType
}
}
}
if newType, ok := replace[fieldName]; ok {
f.Type = newType
}
fields = append(fields, f)
}
return reflect.StructOf(fields), nil
case reflect.Slice:
for replaceName, replaceType := range replace {
if strings.HasPrefix(replaceName, name+"[]") {
if replaceName == name+"[]" {
//full match
return replaceType, nil
} else {
elemType, err := clone(name+"[]", t.Elem(), replace)
if err != nil {
return t, errors.Wrapf(err, "failed to clone slice elem type")
}
return reflect.SliceOf(elemType), nil
}
} else {
return t, nil
}
}
return t, errors.Errorf("NYI")
default:
}
return t, errors.Errorf("cannot clone %v %s", t.Kind(), t.Name())
}