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package serde
import (
"reflect"
)
// Indirect will walk a value's interface or pointer value types. Returning
// the final value or the value a unmarshaler is defined on.
//
// Based on the enoding/json type reflect value type indirection in Go Stdlib
// https://golang.org/src/encoding/json/decode.go Indirect func.
func Indirect(v reflect.Value, decodingNull bool) reflect.Value {
v0 := v
haveAddr := false
if v.Kind() != reflect.Ptr && v.Type().Name() != "" && v.CanAddr() {
v = v.Addr()
haveAddr = true
}
for {
if v.Kind() == reflect.Interface && !v.IsNil() {
e := v.Elem()
if e.Kind() == reflect.Ptr && !e.IsNil() && (!decodingNull || e.Elem().Kind() == reflect.Ptr) {
haveAddr = false
v = e
continue
}
}
if v.Kind() != reflect.Ptr {
break
}
if v.Elem().Kind() != reflect.Ptr && decodingNull && v.CanSet() {
break
}
if v.IsNil() {
v.Set(reflect.New(v.Type().Elem()))
}
if haveAddr {
v = v0
haveAddr = false
} else {
v = v.Elem()
}
}
return v
}
// PtrToValue given the input value will dereference pointers and returning the element pointed to.
func PtrToValue(in interface{}) interface{} {
v := reflect.ValueOf(in)
if v.Kind() == reflect.Ptr {
v = v.Elem()
}
if !v.IsValid() {
return nil
}
if v.Kind() == reflect.Ptr {
return PtrToValue(v.Interface())
}
return v.Interface()
}
// IsZeroValue returns whether v is the zero-value for its type.
func IsZeroValue(v reflect.Value) bool {
switch v.Kind() {
case reflect.Invalid:
return true
case reflect.Array:
return v.Len() == 0
case reflect.Map, reflect.Slice:
return v.IsNil()
case reflect.String:
return v.Len() == 0
case reflect.Bool:
return !v.Bool()
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
return v.Int() == 0
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
return v.Uint() == 0
case reflect.Float32, reflect.Float64:
return v.Float() == 0
case reflect.Interface, reflect.Ptr:
return v.IsNil()
}
return false
}
// ValueElem walks interface and pointer types and returns the underlying element.
func ValueElem(v reflect.Value) reflect.Value {
switch v.Kind() {
case reflect.Interface, reflect.Ptr:
for v.Kind() == reflect.Interface || v.Kind() == reflect.Ptr {
v = v.Elem()
}
}
return v
}
|
