feat(tvix-store): Improve tvix-store copy. r/8916

This change contains 2 improvements to the tvix-store copy command:

1. Allows reading the reference graph from stdin, using `-` argument
2. Supports json representation produced by `nix path-info --json`
   command.

In general it makes is easier and faster to import arbitrary closures
from an existing nix store with e.g the following command:

```
nix path-info ./result --json --closure-size --recursive | \
  jq -s '{closure: add}' | \
  tvix-store copy -
```

Change-Id: Id6eea2993da233ecfbdc186f1a8c37735b686264
Reviewed-on: https://cl.tvl.fyi/c/depot/+/12765
Tested-by: BuildkiteCI
Reviewed-by: flokli <flokli@flokli.de>

1 files changed, 16 insertions, 0 deletions

diff --git a/tvix/nix-compat/src/narinfo/signature.rs b/tvix/nix-compat/src/narinfo/signature.rs
index 8df77019cd8f..2005a5cb60df 100644
--- a/tvix/nix-compat/src/narinfo/signature.rs
+++ b/tvix/nix-compat/src/narinfo/signature.rs
@@ -92,6 +92,12 @@ where
             bytes: self.bytes,
         }
     }
+    pub fn to_owned(&self) -> Signature<String> {
+        Signature {
+            name: self.name.to_string(),
+            bytes: self.bytes,
+        }
+    }
 }
 
 impl<'a, 'de, S> Deserialize<'de> for Signature<S>
@@ -133,6 +139,16 @@ where
     }
 }
 
+impl<S> std::hash::Hash for Signature<S>
+where
+    S: AsRef<str>,
+{
+    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
+        state.write(self.name.as_ref().as_bytes());
+        state.write(&self.bytes);
+    }
+}
+
 #[derive(Debug, thiserror::Error, PartialEq, Eq)]
 pub enum Error {
     #[error("Invalid name: {0}")]