spki: add AlgorithmIdentifierRef::to_owned method

[baloo]

No description provided.

[tarcieri]

Perhaps we can define some traits for this, since we can't use std::borrow::ToOwned (since this isn't a reference conversion).

It would be nice to ensure there's always a reciprocal operation ala std::borrow::Borrow.

[baloo]

I'm pretty bad at naming things, but any opinion?

pubtraitDerBorrow{typeBorrowed<'b>whereSelf:'b;fnder_borrow<'a>(&'aself) -> Self::Borrowed<'a>;}pubtraitDerToOwned<'a>{typeDerOwned:DerBorrow<Borrowed<'a> = Self>whereSelf:'a;fnto_der_owned(&self) -> Self::DerOwned;}impl<'a>DerToOwned<'a>forAlgorithmIdentifierRef<'a>{typeDerOwned = AlgorithmIdentifierOwned;fnto_der_owned(&self) -> Self::DerOwned{AlgorithmIdentifier{oid:self.oid,parameters:self.parameters.map(|p| p.into()),}}}implDerBorrowforAlgorithmIdentifierOwned{typeBorrowed<'a> = AlgorithmIdentifierRef<'a>;fnder_borrow<'a>(&'aself) -> AlgorithmIdentifierRef<'a>{AlgorithmIdentifier{oid:self.oid,parameters:self.parameters.as_ref().map(AnyRef::from),}}}

Compiler seems happy.

[tarcieri]

That looks okay naming aside. Let me think about that for a bit.

[tarcieri]

Naming wise, for starters, the "borrowed" types are owned *Ref types, so perhaps ToRef instead of ToBorrowed?

[baloo]

pubtraitOwnedToRef{typeBorrowed<'b>whereSelf:'b;fnto_ref<'a>(&'aself) -> Self::Borrowed<'a>;}pubtraitRefToOwned<'a>{typeOwned:OwnedToRef<Borrowed<'a> = Self>whereSelf:'a;fnto_owned(&self) -> Self::Owned;}

[tarcieri]

Looking better… maybe RefToOwned and OwnedToRef?