[vlc-devel] [PATCH 7/7] vout: display: pass the vout_display_priv_t directly in internal calls

[Steve Lhomme]

On 2019-10-10 9:15, Thomas Guillem wrote:
> 
> 
> On Thu, Oct 10, 2019, at 08:45, Steve Lhomme wrote:
>> On 2019-10-10 8:29, Rémi Denis-Courmont wrote:
>>> And I disagree with the other patch too, so...
>>>
>>> This is totally against common practices for doing OOP-like code in
>>> non-OOP languages like C. You can't even do that sort of change in OOP...
>>
>> In C++ when you have callbacks it's common to cast the opaque pointer
>> back to the instance pointer and then call a method on the object. You
>> never call each internal function of the class with the opaque pointer
>> and cast it each time. This is exactly similar to what I want to avoid here.
> 
> But it's not done like that in 90% of the VLC code base. We never decided to change it. I'm very fine with the current scheme.
> 
> I already had to move back every functions from priv to public because of an API that needed more contexts (like, logging, variable...).

I don't think using casts because one day it may not be a cast anymore 
is a good enough reason to use a cast.

>>
>>> Le 10 octobre 2019 09:15:00 GMT+03:00, Steve Lhomme <robux4 at ycbcr.xyz> a
>>> écrit :
>>>
>>>      On 2019-10-09 18:19, Rémi Denis-Courmont wrote:
>>>
>>>          Hi,
>>>
>>>          This feels very backward. We don't normally pass the private
>>>          data. And the
>>>          compilers are perfectly capable to optimize the back-and-forth
>>>          conversion so
>>>          the change is completely useless.
>>>
>>>
>>>      container_of() is a glorified cast. One should not use cast unless
>>>      there's no other option.
>>>
>>>      This is exactly the same as was done in
>>>      `a46508d9dd8eeccc8e8fa778b331f6c027db84c7`.
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