package patcher
import (
"errors"
"fmt"
"reflect"
"unsafe"
)
func SetUnexportedField(ptr interface{}, fieldName string, value interface{}) error {
v := reflect.ValueOf(ptr)
if v.Kind() != reflect.Ptr || v.IsNil() {
return errors.New("ptr must be a non-nil pointer to a struct")
}
elem := v.Elem()
if elem.Kind() != reflect.Struct {
return errors.New("ptr must point to a struct")
}
field := elem.FieldByName(fieldName)
if !field.IsValid() {
return fmt.Errorf("field %q not found in struct", fieldName)
}
val := reflect.ValueOf(value)
if !val.IsValid() {
val = reflect.Zero(field.Type())
} else {
if !val.Type().AssignableTo(field.Type()) {
if val.Type().ConvertibleTo(field.Type()) {
val = val.Convert(field.Type())
} else {
return fmt.Errorf("value of type %s is not assignable/convertible to field %s (type %s)",
val.Type(), fieldName, field.Type())
}
}
}
if field.CanSet() {
field.Set(val)
return nil
}
fieldPtr := reflect.NewAt(field.Type(), unsafe.Pointer(field.UnsafeAddr()))
fieldPtr.Elem().Set(val)
return nil
}
func GetUnexportedField(ptr interface{}, fieldName string) (interface{}, error) {
v := reflect.ValueOf(ptr)
if v.Kind() != reflect.Ptr || v.IsNil() {
return nil, errors.New("ptr must be a non-nil pointer to a struct")
}
elem := v.Elem()
if elem.Kind() != reflect.Struct {
return nil, errors.New("ptr must point to a struct")
}
field := elem.FieldByName(fieldName)
if !field.IsValid() {
return nil, fmt.Errorf("field %q not found in struct", fieldName)
}
if field.CanInterface() {
return field.Interface(), nil
}
fieldPtr := reflect.NewAt(field.Type(), unsafe.Pointer(field.UnsafeAddr()))
return fieldPtr.Elem().Interface(), nil
}
