feat(tvix/store/blobservice): implement seek r/6434

For memory and sled, it's trivial, as we already have a Cursor<Vec<u8>>.
For gRPC, we simply reject going backwards, and skip n bytes for now.

Once the gRPC protocol gets support for offsets and verified streaming,
this can be improved.

Change-Id: I734066a514aed287ea3db64bfb1680911ac1eeb0
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8885
Autosubmit: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>

1 files changed, 2 insertions, 2 deletions

diff --git a/tvix/store/src/blobservice/memory.rs b/tvix/store/src/blobservice/memory.rs
index 8963deefd42b..fa2826fe3112 100644
--- a/tvix/store/src/blobservice/memory.rs
+++ b/tvix/store/src/blobservice/memory.rs
@@ -5,7 +5,7 @@ use std::{
 };
 use tracing::{instrument, warn};
 
-use super::{BlobService, BlobWriter};
+use super::{BlobReader, BlobService, BlobWriter};
 use crate::{B3Digest, Error};
 
 #[derive(Clone, Default)]
@@ -36,7 +36,7 @@ impl BlobService for MemoryBlobService {
         Ok(db.contains_key(digest))
     }
 
-    fn open_read(&self, digest: &B3Digest) -> Result<Option<Box<dyn io::Read + Send>>, Error> {
+    fn open_read(&self, digest: &B3Digest) -> Result<Option<Box<dyn BlobReader>>, Error> {
         let db = self.db.read().unwrap();
 
         match db.get(digest).map(|x| Cursor::new(x.clone())) {