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

[Programmingkid]

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.