new

static VALUE
dir_initialize(int argc, VALUE *argv, VALUE dir)
{
    struct dir_data *dp;
    rb_encoding  *fsenc;
    VALUE dirname, opt, orig;
    static ID keyword_ids[1];
    const char *path;

    if (!keyword_ids[0]) {
        keyword_ids[0] = rb_id_encoding();
    }

    fsenc = rb_filesystem_encoding();

    rb_scan_args(argc, argv, "1:", &dirname, &opt);

    if (!NIL_P(opt)) {
        VALUE enc;
        rb_get_kwargs(opt, keyword_ids, 0, 1, &enc);
        if (enc != Qundef && !NIL_P(enc)) {
            fsenc = rb_to_encoding(enc);
        }
    }

    FilePathValue(dirname);
    orig = rb_str_dup_frozen(dirname);
    dirname = rb_str_encode_ospath(dirname);
    dirname = rb_str_dup_frozen(dirname);

    TypedData_Get_Struct(dir, struct dir_data, &dir_data_type, dp);
    if (dp->dir) closedir(dp->dir);
    dp->dir = NULL;
    RB_OBJ_WRITE(dir, &dp->path, Qnil);
    dp->enc = fsenc;
    path = RSTRING_PTR(dirname);
    dp->dir = opendir_without_gvl(path);
    if (dp->dir == NULL) {
        int e = errno;
        if (rb_gc_for_fd(e)) {
            dp->dir = opendir_without_gvl(path);
        }
#ifdef HAVE_GETATTRLIST
        else if (e == EIO) {
            u_int32_t attrbuf[1];
            struct attrlist al = {ATTR_BIT_MAP_COUNT, 0};
            if (getattrlist(path, &al, attrbuf, sizeof(attrbuf), FSOPT_NOFOLLOW) == 0) {
                dp->dir = opendir_without_gvl(path);
            }
        }
#endif
        if (dp->dir == NULL) {
            RB_GC_GUARD(dirname);
            rb_syserr_fail_path(e, orig);
        }
    }
    RB_OBJ_WRITE(dir, &dp->path, orig);

    return dir;
}