Re: [Qemu-devel] [PATCH 0/3] scsi: remove lsi53c895a_create() and lsi53c810_create() functions

[Peter Maydell]

On 6 September 2018 at 17:40, Thomas Huth <address@hidden> wrote:
> On 2018-09-06 16:50, Peter Maydell wrote:
>> Nothing typically does, but the "modern" style of having QOM objects which
>> use other QOM objects do so by embedding the child object's struct into
>> the struct of the parent requires that the struct definition is available.
>
> But in this case we don't have anything that "inherits" from LSIState,
> so shouldn't we rather follow the "information hiding" principle and
> keep the state local to the lsi53c895a.c file? If you want to use a
> "LSIState *" from another .c file, you can still put an "anonymous"
>
>  struct LSIState;
>  typedef struct LSIState LSIState;

This doesn't work for

typedef struct MySoC {
   MyUART uart;
   LSIState scsi;
   ...
} MySoC;

This isn't inheritance, it's just use ("has-a", not "is-a").

> in a header somewhere without revealing the implementation.
>
> I'm fine with putting the whole LSIState into a header file if we really
> need it, but in this case, I don't see the point.

Looking at the rest of the series there doesn't seem to be
any code that wants to do use-by-embedding, so we can
certainly postpone moving the struct into the header file
until we need it.

thanks
-- PMM