Make sure `Found{Hosts, Addrs}` have `is_empty` and `len` methods

NLnetLabs / domain

A DNS library for Rust.

https://nlnetlabs.nl/projects/domain/about/

BSD 3-Clause "New" or "Revised" License

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Make sure `Found{Hosts, Addrs}` have `is_empty` and `len` methods #316

Closed tertsdiepraam closed 5 months ago

tertsdiepraam commented 5 months ago

I noticed that FoundAddrs did not have an is_empty method while implementing the lookup command for dnsi. I also figured that len methods for FoundHosts and FoundAddrs would be a nice addition.

I just kind of guessed the implementation of these methods, so I don't really know whether they are correct :)

partim commented 5 months ago

The answer sections can contain other records (even legitimately, any possible CNAME records go there), so using the ANCOUNT can be wrong. Which also means that the is_empty impl in FoundHosts is potentially wrong and should be removed.

We could impl methods based on using self.iter(), but given that isn’t exactly free, maybe we shouldn’t hide the O(n)-ness.