Re: [Qemu-devel] Should we auto-generate IDs?

[Programmingkid]

On Sep 1, 2015, at 10:43 AM, Kevin Wolf wrote:

> Am 01.09.2015 um 16:18 hat Programmingkid geschrieben:
>> 
>> On Sep 1, 2015, at 8:34 AM, Kevin Wolf wrote:
>> 
>>> Am 27.08.2015 um 14:32 hat Jeff Cody geschrieben:
>>>> I'm not married to the ID generation scheme I proposed.  
>>>> 
>>>> What I am trying to do, however, is have a technical discussion on
>>>> generating an ID in a well-formed manner.  And hopefully, in a way
>>>> that is useful to all interested subsystems, if possible.
>>>> 
>>>> Do you disagree with the requirements I listed above?  If so, it would
>>>> be useful to begin the discussion around that.  For ease of
>>>> discussion, I'll list them again:
>>>> 
>>>> * Reserved namespaces
>>>> * Uniqueness
>>>> * Non-predictable (to avoid inadvertently creating a de facto ABI)
>>>> 
>>>> 
>>>> . . .
>>>> 
>>>> On the generation scheme proposed above:
>>>> 
>>>> I understand that something you desire is an ID that is easier to
>>>> type.
>>>> 
>>>> If we wanted to make it shorter, perhaps we could have the number
>>>> counter be variable length:
>>>> 
>>>>           qemu#ss#D#XY
>>>>             |   | | |
>>>> qemu reserved -   | | |
>>>>                 | | |
>>>> subsystem name ---| | |
>>>>                   | |
>>>>   counter --------| |
>>>>                     |
>>>>   2-digit random ---|
>>> 
>>> Even with keeping all of the information in there we can shorten the ID
>>> a bit more: # at the start is enough to mark it as autogenerated, the
>>> subsystem seems nice to have in there anyway, and the # separators can
>>> be removed without making the ID less unique (assuming that subsystems
>>> never end in a digit). This results in an ID that looks like a three (or
>>> more) digit number for the subsystem, where the last two digits are
>>> random, like this:
>>> 
>>>   #block150
>>>   #block219
>>>   #block344
>>>   ...
>>> 
>>> That seems easy to type and still fulfills all of the criteria.
>>> 
>>> Kevin
>> 
>> I do know that some really want an indicator that shows that an ID is 
>> auto-generated. But we could still do this and keep the ID short. What if 
>> the auto-generated ID just started with a character the user could never use 
>> at the beginning of the ID. I suggest we use an underscore to indicate 
>> machine-generated ID's. Something like this _1. It is very simple and 
>> effective. 
> 
> That's what I already did. # is a reserved character. I don't think
> something like #block150 is unreasonably long, it's a bit more
> descriptive than _1, and it fulfills all of Jeff's criteria, which _1
> clearly doesn't.

The rules aren't all necessary.