dirReadBsd

fn dirReadBsd(userdata: ?*anyopaque, dr: *Dir.Reader, buffer: []Dir.Entry) Dir.Reader.Error!usize {
    const t: *Threaded = @ptrCast(@alignCast(userdata));
    _ = t;
    var buffer_index: usize = 0;
    while (buffer.len - buffer_index != 0) {
        if (dr.end - dr.index == 0) {
            // Refill the buffer, unless we've already created references to
            // buffered data.
            if (buffer_index != 0) break;
            if (dr.state == .reset) {
                posixSeekTo(dr.dir.handle, 0) catch |err| switch (err) {
                    error.Unseekable => return error.Unexpected,
                    else => |e| return e,
                };
                dr.state = .reading;
            }
            const syscall: Syscall = try .start();
            const n: usize = while (true) {
                const rc = posix.system.getdents(dr.dir.handle, dr.buffer.ptr, dr.buffer.len);
                switch (posix.errno(rc)) {
                    .SUCCESS => {
                        syscall.finish();
                        break @intCast(rc);
                    },
                    .INTR => {
                        try syscall.checkCancel();
                        continue;
                    },
                    else => |e| {
                        syscall.finish();
                        switch (e) {
                            .BADF => |err| return errnoBug(err), // Dir is invalid or was opened without iteration ability
                            .FAULT => |err| return errnoBug(err),
                            .NOTDIR => |err| return errnoBug(err),
                            .INVAL => |err| return errnoBug(err),
                            // Introduced in freebsd 13.2: directory unlinked
                            // but still open. To be consistent, iteration ends
                            // if the directory being iterated is deleted
                            // during iteration.
                            .NOENT => {
                                dr.state = .finished;
                                return 0;
                            },
                            else => |err| return posix.unexpectedErrno(err),
                        }
                    },
                }
            };
            if (n == 0) {
                dr.state = .finished;
                return 0;
            }
            dr.index = 0;
            dr.end = n;
        }
        const bsd_entry = @as(*align(1) posix.system.dirent, @ptrCast(&dr.buffer[dr.index]));
        const next_index = dr.index +
            if (@hasField(posix.system.dirent, "reclen")) bsd_entry.reclen else bsd_entry.reclen();
        dr.index = next_index;

        const name = @as([*]u8, @ptrCast(&bsd_entry.name))[0..bsd_entry.namlen];

        const skip_zero_fileno = switch (native_os) {
            // fileno=0 is used to mark invalid entries or deleted files.
            .openbsd, .netbsd => true,
            else => false,
        };
        if (std.mem.eql(u8, name, ".") or std.mem.eql(u8, name, "..") or
            (skip_zero_fileno and bsd_entry.fileno == 0))
        {
            continue;
        }

        const entry_kind: File.Kind = switch (bsd_entry.type) {
            posix.DT.BLK => .block_device,
            posix.DT.CHR => .character_device,
            posix.DT.DIR => .directory,
            posix.DT.FIFO => .named_pipe,
            posix.DT.LNK => .sym_link,
            posix.DT.REG => .file,
            posix.DT.SOCK => .unix_domain_socket,
            posix.DT.WHT => .whiteout,
            else => .unknown,
        };
        buffer[buffer_index] = .{
            .name = name,
            .kind = entry_kind,
            .inode = bsd_entry.fileno,
        };
        buffer_index += 1;
    }
    return buffer_index;
}