[libvirt] [GSoC] Design ideas for implementing cleanup attribute

[Michal Privoznik]

On 05/28/2018 09:34 AM, Sukrit Bhatnagar wrote:
> 
> This is what new macros will look like:
> 
> # define _VIR_TYPE_PTR(type) type##Ptr
> 
> # define _VIR_ATTR_AUTOFREE_PTR(type)  __attribute__((cleanup(type##Free)))
> # define _VIR_ATTR_AUTOCLOSE_PTR(type) __attribute__((cleanup(type##Close)))
> # define _VIR_ATTR_AUTOCLEAN_PTR(type) __attribute__((cleanup(type##Clean)))
> 
> # define VIR_AUTOFREE_PTR(type) _VIR_ATTR_AUTOFREE_PTR(type) _VIR_TYPE_PTR(type)
> 
> 
> The problem is that our vir*Free functions take on vir*Ptr as the
> parameter and not
> vir*Ptr * (pointer to it).
> 
> For example, instead of:
> void virArpTableFree(virArpTablePtr table);
> 
> we would need:
> void virArpTableFree(virArpTablePtr *table);
> 
> if we declare something like:
> VIR_AUTOFREE_PTR(virArpTable) table = NULL;
> 
> 
> Also, I tried to add a new function:
> void virArpTablePtrFree(virArpTablePtr *table)
> {
>     size_t i;
> 
>     if (!*table)
>         return;
> 
>     for (i = 0; i < (*table)->n; i++) {
>         VIR_FREE((*table)->t[i].ipaddr);
>         VIR_FREE((*table)->t[i].mac);
>     }
>     VIR_FREE((*table)->t);
>     VIR_FREE((*table));
>     VIR_FREE(table);

As Erik pointed out, this last VIR_FREE(table) looks fishy. However, do
you have patch that I can apply and reproduce?

Michal