feat(nix-compat/narinfo/signature): generalize name field r/8540

Requiring `name` to be a `&str` means it'll get annoying to pass around
`Signature`, but being able to pass them around in an owned fashion is
kinda a requirement for a stronger typed `PathInfo` struct, where we
want to have full ownership.

Rework the `Signature` struct to become generic over the type of the
`name` field. This means, it becomes possible to have owned versions
of it.

We don't want to impose `String` or `SmolStr` for example, but want to
leave it up to the nix-compat user to decide.

Provide a type alias for the existing `&str` variant (`SignatureRef`),
and use it where we previously used the non-generic `Signature` one.

Add some tests to ensure it's possible to *use* `Signature` with both
`String` and `SmolStr` (but only pull in `smol_str` as dev dependency
for the tests).

Also, add some more docstrings, these were a bit sparse.

Change-Id: I3f75691498c6bda9cd072d2d9dac83c4f6c57287
Reviewed-on: https://cl.tvl.fyi/c/depot/+/12253
Autosubmit: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI
Reviewed-by: raitobezarius <tvl@lahfa.xyz>

1 files changed, 4 insertions, 4 deletions

diff --git a/tvix/nix-compat/src/narinfo/mod.rs b/tvix/nix-compat/src/narinfo/mod.rs
index a77eba200f8d..21aecf80b5a2 100644
--- a/tvix/nix-compat/src/narinfo/mod.rs
+++ b/tvix/nix-compat/src/narinfo/mod.rs
@@ -32,7 +32,7 @@ mod signing_keys;
 mod verifying_keys;
 
 pub use fingerprint::fingerprint;
-pub use signature::{Error as SignatureError, Signature};
+pub use signature::{Error as SignatureError, Signature, SignatureRef};
 pub use signing_keys::parse_keypair;
 pub use signing_keys::{Error as SigningKeyError, SigningKey};
 pub use verifying_keys::{Error as VerifyingKeyError, VerifyingKey};
@@ -51,7 +51,7 @@ pub struct NarInfo<'a> {
     pub references: Vec<StorePathRef<'a>>,
     // authenticity
     /// Ed25519 signature over the path fingerprint
-    pub signatures: Vec<Signature<'a>>,
+    pub signatures: Vec<SignatureRef<'a>>,
     /// Content address (for content-defined paths)
     pub ca: Option<CAHash>,
     // derivation metadata
@@ -246,7 +246,7 @@ impl<'a> NarInfo<'a> {
                     };
                 }
                 "Sig" => {
-                    let val = Signature::parse(val)
+                    let val = SignatureRef::parse(val)
                         .map_err(|e| Error::UnableToParseSignature(signatures.len(), e))?;
 
                     signatures.push(val);
@@ -578,7 +578,7 @@ CA: fixed:r:sha1:1ak1ymbmsfx7z8kh09jzkr3a4dvkrfjw
 
         // ensure the signature is added
         let new_sig = narinfo.signatures.last().unwrap();
-        assert_eq!(signing_key.name(), new_sig.name());
+        assert_eq!(signing_key.name(), *new_sig.name());
 
         // verify the new signature against the verifying key
         let verifying_key = super::VerifyingKey::parse(super::DUMMY_VERIFYING_KEY)