Re: [Qemu-devel] Re: [RFC] QCFG: a new mechanism to replace QemuOpts and option handling

[Markus Armbruster]

Kevin Wolf <address@hidden> writes:

> Am 15.03.2011 14:37, schrieb Anthony Liguori:
>> On 03/15/2011 06:21 AM, Kevin Wolf wrote:
>>> Am 14.03.2011 18:48, schrieb Anthony Liguori:
>>>> I've got a spec written up at http://wiki.qemu.org/Features/QCFG.
>>>> Initial code is in my QAPI tree.
>>> One question about a small detail on this wiki page:
>>>
>>>> typedef struct BlockdevConfig {
>>>>      char * file;
>>>>      struct BlockdevConfig * backing_file;
>>>>
>>>>      struct BlockdevConfig * next;
>>>> } BlockdevConfig;
>>> What is the 'next' pointer used for,
>> 
>> This is a standard part of QAPI.  All types get a next pointer added 
>> such that we can support lists of complex types.
>
> Only a single list for each object.

Don't even think of trees.  Yuck.

>>>   are you going to store a list of
>>> all -blockdev options used? And why isn't it a QLIST or something?
>> 
>> Two reasons.  QLIST requires another type for the head of the list which 
>> would complicate things overall.  Second is that these types are part of 
>> the libqmp interface and I didn't want to force qemu-queue on any 
>> consumer of libqmp.
>
> And now you force existing qemu code to go back to open coded lists,
> which is arguably a step backwards. I don't think this is any better
> than forcing the (non-existent) users of libqmp to include one
> additional header file.

Agree.  Let's not screw up our internal interfaces for the sake of an
external interface that may or may not turn out to be viable.