func openEntry(cache *cdc.DiskCache, url, addr, dir string) *cdc.Entry {
var entry *cdc.Entry
var err error
if addr != "" {
id, era := strconv.ParseUint(addr, 10, 32)
if era != nil {
log.Fatal(era)
}
entry, err = cdc.OpenEntry(cdc.CacheAddr(id), dir)
} else if url != "" {
entry, err = cache.OpenURL(url)
}
if err != nil {
log.Fatal(err)
}
return entry
}
