* Marvin Renich <m...@renich.org> [171002 11:31]:
> * Chris Hopkins <cbehopk...@gmail.com> [171002 10:52]:
> > out, err := os.Create(potential_file_name)
> > switch t := err.(type) {
> > case *os.PathError:
> > switch t.Err {
> > case os.ErrNotExist:
> > log.Fatal("Invalid filename", potential_file_name)
> > case os.ErrInvalid:
> > log.Fatal("Invalid argument", potential_file_name)
> > default :
Additionally, os.Create, os.Open, and os.OpenFile all guarantee (via
their documentation and the Go 1 Compatibility Guarantee) that if they
return a non-nil error, it will be of type *os.PathError, so you could,
if you wish, replace the "switch t := err.(type)" with
t = err.(*os.PathError) and if it panics, you can file a bug.
Furthermore, because the current implementation is extremely unlikely to
change, you can simplify even more. I would write this as:
var out, err = os.Create(potential_file_name)
if err != nil {
var pe = err.(*os.PathError) // let it panic or use the ,ok trick as
below
var en, ok = pe.Err.(syscall.Errno) // not a Go 1 Compat guarantee, so
handle failed type assertion
if !ok {
log.Fatalf("Unexpected error from os.Create: %s\n", pe)
}
switch en {
case syscall.EEXIST:
...
case syscall.EISDIR:
...
case syscall.EINVAL:
...
}
}
This code is much more readable than the nested type switch that you are
using. Note that os.ErrNotExist and os.ErrInvalid are not of type
*os.PathError and os.Create will never return either of them (promised
by Go 1 Compat).
If the !ok test ever succeeds, you know that the implementation of
os.OpenFile has changed.
...Marvin
--
You received this message because you are subscribed to the Google Groups
"golang-nuts" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to golang-nuts+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
