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package btrfsitem
import (
"fmt"
"reflect"
"lukeshu.com/btrfs-tools/pkg/binstruct"
"lukeshu.com/btrfs-tools/pkg/btrfs/internal"
)
type Type = internal.ItemType
type Item interface {
isItem()
}
type Error struct {
Dat []byte
Err error
}
func (Error) isItem() {}
func (o Error) MarshalBinary() ([]byte, error) {
return o.Dat, nil
}
func (o *Error) UnmarshalBinary(dat []byte) (int, error) {
o.Dat = dat
return len(dat), nil
}
// Rather than returning a separate error value, return an Error item.
func UnmarshalItem(keytyp Type, dat []byte) Item {
gotyp, ok := keytype2gotype[keytyp]
if !ok {
return Error{
Dat: dat,
Err: fmt.Errorf("btrfsitem.UnmarshalItem(typ=%v, dat): unknown item type", keytyp),
}
}
retPtr := reflect.New(gotyp)
n, err := binstruct.Unmarshal(dat, retPtr.Interface())
if err != nil {
return Error{
Dat: dat,
Err: fmt.Errorf("btrfsitem.UnmarshalItem(typ=%v, dat): %w", keytyp, err),
}
}
if n < len(dat) {
return Error{
Dat: dat,
Err: fmt.Errorf("btrfsitem.UnmarshalItem(typ=%v, dat): left over data: got %d bytes but only consumed %d",
keytyp, len(dat), n),
}
}
return retPtr.Elem().Interface().(Item)
}
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