[PATCH wayland] server: add helper functions for wl_global

[Bill Spitzak]

On 03/09/2015 11:41 PM, Pekka Paalanen wrote:
> On Mon, 09 Mar 2015 11:13:20 -0700
> Bill Spitzak <spitzak at gmail.com> wrote:
>
>> On 03/09/2015 06:34 AM, Pekka Paalanen wrote:
>>
>>> What performance concerns do you have?
>>
>> I suspect the worry was about allocating and freeing a temporary array,
>> but your idea of the caller passing the array avoids it.
>>
>> I feel like it would be better to reduce the number of arguments to only
>> a set that there is some possibility the backend may optimize to
>> something other than a linear search. My main concern is the "data" as
>> there are instances where using NULL is valid and something you would
>> search for, and it seems really unlikely a compositor will arrange the
>> globals into sets or sorted depending on their data pointer. I'm also
>> not sure if anybody would pass a specific version number without also
>> passing a specific bind function, though I don't understand enough about
>> the version control to be sure.
>
> I think any possible performance impact is greatly exaggerated here.
>
> This is code that runs few times at most during program init or
> perhaps on GPU hotplug or other extremely heavy operations. It is not
> ran repeatedly during runtime. Therefore I do not see any need to try to
> invent the most efficient implementation, because speed here simply
> does not matter at all.
>
> Just go with an API that is clear, and easy to use and clean up
> afterwards.

Your idea of passing an array for it to fill in seems perfectly acceptable.