[libvirt] [PATCH v3 2/2] network: Add code for setting network bandwidth for ethernet interfaces

[Eric Blake]

On 10/08/2014 04:10 PM, Anirban Chakraborty wrote:

>> Needs rework after my comments on 1/2.  I also wonder if this should
>> just be folded in to that patch, and/or made into a switch statement
>> where the compiler forces us to think about any future
>> VIR_DOMAIN_NET_TYPE_* additions on whether they should return true or
>> false.

>> bool virNetDevSupportBandwidth(virDomainNetType type)
>> {
>>    switch (type) {
>>    case VIR_DOMAIN_NET_TYPE_BRIDGE:
>>    case VIR_DOMAIN_NET_TYPE_NETWORK:
>>    case VIR_DOMAIN_NET_TYPE_DIRECT:
>>    case VIR_DOMAIN_NET_TYPE_ETHERNET:
>>        return true;
>>    case VIR_DOMAIN_NET_TYPE_USER:
>>    case VIR_DOMAIN_NET_TYPE_VHOSTUSER:
>>    case VIR_DOMAIN_NET_TYPE_SERVER:
>>    case VIR_DOMAIN_NET_TYPE_CLIENT:
>>    case VIR_DOMAIN_NET_TYPE_MCAST:
>>    case VIR_DOMAIN_NET_TYPE_INTERNAL:
>>    case VIR_DOMAIN_NET_TYPE_HOSTDEV:
>>    case VIR_DOMAIN_NET_TYPE_LAST:
>>        /* cover all enums to appease the compiler */ ;
>>    }
>>    return false;
>> }
> 
> We could have the function defined with a switch, however, instead of
> listing all the types, I could return false from the default case.
> 
> Something like:
>     switch (type) {
>     case VIR_DOMAIN_NET_TYPE_BRIDGE:
>     case VIR_DOMAIN_NET_TYPE_NETWORK:
>     case VIR_DOMAIN_NET_TYPE_DIRECT:
>     case VIR_DOMAIN_NET_TYPE_ETHERNET:
>         return true;
> 
>     default;
>         return false;

Alas, using a default case means the compiler can no longer tell you
about missed cases.  I wrote my example to intentionally spell out ALL
cases without a default, in order to ensure the compiler will loudly
warn if we add another enum in the future.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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