Re: [PATCH 1/5] 9pfs: introduce P9Array

["Daniel P. Berrangé" <berrange@redhat.com>]

On Fri, Oct 01, 2021 at 04:26:17PM +0200, Christian Schoenebeck wrote:
> Implements deep auto free of arrays while retaining common C-style
> squared bracket access. Main purpose of this API is to get rid of
> error prone individual array deallocation pathes in user code, i.e.
> turning something like this:
> 
>   void doSomething(size_t n) {
>       Foo *foos = malloc(n * sizeof(Foo));
>       for (...) {
>           foos[i].s = malloc(...);
>           if (...) {
>               goto out;
>           }
>       }
>   out:
>       if (...) {
>           for (...) {
>               /* deep deallocation */
>               free(foos[i].s);
>           }
>           /* array deallocation */
>           free(foos);
>       }
>   }
> 
> into something more simple and safer like:
> 
>   void doSomething(size_t n) {
>       P9ARRAY_REF(Foo) foos = NULL;
>       P9ARRAY_NEW(Foo, foos, n);
>       for (...) {
>           foos[i].s = malloc(...);
>           if (...) {
>               return; /* array auto freed here */
>           }
>       }
>       /* array auto freed here */
>   }

As explained before, I'm against the idea of introducing new ways
to automatically free local variables that are not using g_auto*
functionality. It is not following the QEMU wide coding style
that is documented.


Regards,
Daniel
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