refactor(tvix/store/directorysvc): use [u8; 32] instead of Vec<u8> r/6014

Also, simplify the trait interface, only allowing lookups of Directory
objects by their digest.

Change-Id: I6eec28a8cb0557bed9b69df8b8ff99a5e0f8fe35
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8313
Tested-by: BuildkiteCI
Autosubmit: flokli <flokli@flokli.de>
Reviewed-by: tazjin <tazjin@tvl.su>

1 files changed, 2 insertions, 2 deletions

diff --git a/tvix/store/src/proto/mod.rs b/tvix/store/src/proto/mod.rs
index fceb6b5902df..f5945d650ad8 100644
--- a/tvix/store/src/proto/mod.rs
+++ b/tvix/store/src/proto/mod.rs
@@ -236,10 +236,10 @@ impl Directory {
 
     /// Calculates the digest of a Directory, which is the blake3 hash of a
     /// Directory protobuf message, serialized in protobuf canonical form.
-    pub fn digest(&self) -> Vec<u8> {
+    pub fn digest(&self) -> [u8; 32] {
         let mut hasher = blake3::Hasher::new();
 
-        hasher.update(&self.encode_to_vec()).finalize().as_bytes()[..].to_vec()
+        *hasher.update(&self.encode_to_vec()).finalize().as_bytes()
     }
 
     /// validate checks the directory for invalid data, such as: