Re: [Qemu-devel] IDs in QOM

[Paolo Bonzini <pbonzini@redhat.com>]

Il 02/10/2014 16:59, Markus Armbruster ha scritto:
> Andreas Färber <afaerber@suse.de> writes:
> 
>> Am 02.10.2014 um 16:21 schrieb Markus Armbruster:
>>> Andreas Färber <afaerber@suse.de> writes:
>>>
>>>> Am 02.10.2014 um 15:21 schrieb Stefan Hajnoczi:
>>>>> On Wed, Oct 01, 2014 at 02:33:47PM +0200, Markus Armbruster wrote:
>>>>>> Markus Armbruster <armbru@redhat.com> writes:
>>>>>
>>>>> This discussion seems orthogonal to your patch.  But I'm not applying it
>>>>> yet to give more time for discussion/review of the patch.
>>>>>
>>>>>> Is mangling array-ness into the name really a good idea?  Isn't this
>>>>>> type matter, not name matter?
>>>>>
>>>>> I agree.  It's nasty to hack the array selector into the name and will
>>>>> probably cause us pain down the line.
>>>
>>> Andreas?
>>
>> -> Paolo ;)
> 
> Paolo?

Uhm, I had written an answer but Thunderbird ate it.  Oh well.

I think foo[*] is not really a matter of typing, but a matter of
grouping similar children.  It does not really matter if foo[1] is
deleted while foo[2] still exists, and it does not really matter if the
next object created will be foo[1] or foo[3].

While we do not have any example, QOM could support true array
properties, e.g. with type intList.

Also note that while foo[*] was a generalization of MemoryRegion code,
the same idea has also existed forever for devices.
/machine/peripheral_anon and /machine/unattached do not currently use
automatic array-ification via foo[*], but they could.

>> If you just want to call id_wellformed() for -object / object-add, I
>> won't object to restricting it beyond the necessary, but it'll lead to
>> two places doing validity checks for QOM.
> 
> id_wellformed() is *already* called for -object and HMP object-add.
> That's exactly my point!
> 
> Please reread my explanation, and if it's insufficient, ask for
> clarification.
> 
> Subject: IDs in QOM (was: [PATCH] util: Emancipate id_wellformed() from QemuOpts)
> Date: Wed, 01 Oct 2014 14:33:47 +0200
> Message-ID: <87iok46kb8.fsf@blackfin.pond.sub.org>

I think it is okay to keep calling id_wellformed(), since it covers the
QOM-specific constraint that slashes must be outlawed.  It just makes
the children of /objects a bit more restricted in their naming, but that
is harmless because object_del can only delete objects created with
object_add.

Paolo