1 files changed, 28 insertions, 9 deletions

diff --git a/tvix/store/src/blobservice/mod.rs b/tvix/store/src/blobservice/mod.rs
index 53e941795e..e97ccdf335 100644
--- a/tvix/store/src/blobservice/mod.rs
+++ b/tvix/store/src/blobservice/mod.rs
@@ -1,4 +1,6 @@
-use crate::{proto, Error};
+use std::io;
+
+use crate::Error;
 
 mod memory;
 mod sled;
@@ -7,14 +9,31 @@ pub use self::memory::MemoryBlobService;
 pub use self::sled::SledBlobService;
 
 /// The base trait all BlobService services need to implement.
-/// It provides information about how a blob is chunked,
-/// and allows creating new blobs by creating a BlobMeta (referring to chunks
-/// in a [crate::chunkservice::ChunkService]).
+/// It provides functions to check whether a given blob exists,
+/// a way to get a [io::Read] to a blob, and a method to initiate writing a new
+/// Blob, which returns a [BlobWriter], that can be used
 pub trait BlobService {
-    /// Retrieve chunking information for a given blob
-    fn stat(&self, req: &proto::StatBlobRequest) -> Result<Option<proto::BlobMeta>, Error>;
+    type BlobReader: io::Read + Send + std::marker::Unpin;
+    type BlobWriter: BlobWriter + Send;
+
+    /// Check if the service has the blob, by its content hash.
+    fn has(&self, digest: &[u8; 32]) -> Result<bool, Error>;
+
+    /// Request a blob from the store, by its content hash. Returns a Option<BlobReader>.
+    fn open_read(&self, digest: &[u8; 32]) -> Result<Option<Self::BlobReader>, Error>;
+
+    /// Insert a new blob into the store. Returns a [BlobWriter], which
+    /// implements [io::Write] and a [BlobWriter::close].
+    /// TODO: is there any reason we want this to be a Result<>, and not just T?
+    fn open_write(&self) -> Result<Self::BlobWriter, Error>;
+}
 
-    /// Insert chunking information for a given blob.
-    /// Implementations SHOULD make sure chunks referred do exist.
-    fn put(&self, blob_digest: &[u8], blob_meta: proto::BlobMeta) -> Result<(), Error>;
+/// A [io::Write] that you need to close() afterwards, and get back the digest
+/// of the written blob.
+pub trait BlobWriter: io::Write {
+    /// Signal there's no more data to be written, and return the digest of the
+    /// contents written.
+    ///
+    /// This consumes self, so it's not possible to close twice.
+    fn close(self) -> Result<[u8; 32], Error>;
 }