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package internal
import (
"reflect"
)
func MakeSliceNextElemFunc(v reflect.Value) func() reflect.Value {
if v.Kind() == reflect.Array {
var pos int
return func() reflect.Value {
v := v.Index(pos)
pos++
return v
}
}
elemType := v.Type().Elem()
if elemType.Kind() == reflect.Ptr {
elemType = elemType.Elem()
return func() reflect.Value {
if v.Len() < v.Cap() {
v.Set(v.Slice(0, v.Len()+1))
elem := v.Index(v.Len() - 1)
if elem.IsNil() {
elem.Set(reflect.New(elemType))
}
return elem
}
elem := reflect.New(elemType)
v.Set(reflect.Append(v, elem))
return elem
}
}
zero := reflect.Zero(elemType)
return func() reflect.Value {
if v.Len() < v.Cap() {
v.Set(v.Slice(0, v.Len()+1))
return v.Index(v.Len() - 1)
}
v.Set(reflect.Append(v, zero))
return v.Index(v.Len() - 1)
}
}
func Unwrap(err error) error {
u, ok := err.(interface {
Unwrap() error
})
if !ok {
return nil
}
return u.Unwrap()
}
func FieldByIndexAlloc(v reflect.Value, index []int) reflect.Value {
if len(index) == 1 {
return v.Field(index[0])
}
for i, idx := range index {
if i > 0 {
v = indirectNil(v)
}
v = v.Field(idx)
}
return v
}
func indirectNil(v reflect.Value) reflect.Value {
if v.Kind() == reflect.Ptr {
if v.IsNil() {
v.Set(reflect.New(v.Type().Elem()))
}
v = v.Elem()
}
return v
}
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