Re: partition map reorganization

[Hollis Blanchard]

On Nov 2, 2004, at 12:56 AM, Tomas Ebenlendr wrote:
> I have just two questions. (I didn't see the code for a long time, so
> I'm sory if I misunderstand something.)
>
> > struct grub_partition_ops {
> >         grub_err_t (*iterate) (struct grub_disk *disk,
> >                                         int (*hook) (const grub_partition_t
> >                                         partition));
> >         grub_partition_t (*probe) (struct grub_disk *disk, const char *str);
> >         char * (*get_name) (const grub_partition_t p);
> > };
> >
> > Impact to existing code can be minimized with wrappers like this:
> >
> > static inline char *
> > grub_partition_get_name (const grub_partition_t p)
> > {
> >         return p->disk->ops->get_name (p);
> > }
>
> Do you want partition ops to be member of disk structure?

Yes. A disk has a particular partition map format.

> > struct grub_partition {
> >         unsigned long start;
> >         unsigned long len;
> >         unsigned int index;
> >         struct grub_disk_t disk;
> > };
>
> Umm, what about 'type' field? (To be sure that some generic partition 
> is
> the dos one.)

I don't understand what you mean, can you provide an example of how it 
would be used by arch-neutral code? If you're thinking of something 
like this:
        switch (p->type) {
                case DOS_PARTITION:
                        name = dos_get_name(p);
                        break;
                case APPLE_PARTITION:
                        name = apple_get_name(p);
                        break;
        }
... then that is much better handled by calling through the disk->ops 
function pointers:
        name = grub_partition_get_name(p);

Also consider that an Apple partition map entry has a 32-character 
"type" field. How would you represent that as an integer (which I think 
is what you're requesting)?

-Hollis