Function has_capability_cache

src/ls.c:3277–3299

Cache has_capability failure, when it's trivial to do. Like has_capability, but when F's st_dev says it's on a file system lacking capability support, return 0 with ENOTSUP immediately. */

   Like has_capability, but when F's st_dev says it's on a file
   system lacking capability support, return 0 with ENOTSUP immediately.  */
static bool
has_capability_cache (char const *file, struct fileinfo *f)
{
  /* If UNSUPPORTED_CACHED, UNSUPPORTED_DEVICE is the cached
     st_dev of the most recently processed device for which we've
     found that has_capability fails indicating lack of support.  */
  static bool unsupported_cached;
  static dev_t unsupported_device;

  if (f->stat_ok && unsupported_cached && f->stat.st_dev == unsupported_device)
    {
      errno = ENOTSUP;
      return 0;
    }

  bool b = has_capability (file);
  if (f->stat_ok && !b && !acl_errno_valid (errno))
    {
      unsupported_cached = true;
      unsupported_device = f->stat.st_dev;
    }
  return b;
}

static bool
needs_quoting (char const *name)