func Dedup(d *types.Dat, deduper Deduper) (*types.Dat, error) {
dc := new(types.Dat)
dc.CopyHeader(d)
for _, g := range d.Games {
gc := new(types.Game)
gc.CopyHeader(g)
for _, r := range g.Roms {
if !r.Valid() {
continue
}
seen, err := deduper.Seen(r)
if err != nil {
return nil, err
}
if !seen {
gc.Roms = append(gc.Roms, r)
err = deduper.Declare(r)
if err != nil {
return nil, err
}
}
}
if len(gc.Roms) > 0 {
dc.Games = append(dc.Games, gc)
}
}
if len(dc.Games) > 0 {
return dc, nil
}
return nil, nil
}
