impl Clone + Copy for Ref

[nathan]

Since Ref is essentially a reference type, it would be nice if it implemented Clone and Copy when the underlying ByteSlice does. The whole point of zerocopy is not copying, so I imagine cloneing the entire underlying type through the Deref impl (which this would interfere with) is not a common operation.

My use case: I followed the example for parsing a UDP header, so my structs look like this:

struct Header<B: ByteSlice> {
    pub props: Ref<B, Props>,
    pub names: B,
    pub name_hashes: B,
    pub package_ids: Ref<B, [PackageId]>,
// …
}

I can't take &self, do some processing on a Ref, and hand out types with the same lifetime as the underlying slice. But I can't take self either, because I do this for more than one field and Ref: !Clone, so my struct is !Clone too. I'd like to do something like this:

fn cool_packages<'a>(&self) -> impl 'a + Iterator<Item = &'a PackageId> where B: 'a + Clone {
    self.package_ids.clone()
        .into_slice()
        .iter()
        .filter(|p| is_cool(p))
}

Am I missing a soundness issue?

[joshlf]

This should be doable; I'll put it on our roadmap for 0.8.