1 files changed, 41 insertions, 0 deletions
diff --git a/tvix/store/src/blobservice/mod.rs b/tvix/store/src/blobservice/mod.rs
new file mode 100644
index 000000000000..c5a2de124656
--- /dev/null
+++ b/tvix/store/src/blobservice/mod.rs
@@ -0,0 +1,41 @@
+use std::io;
+
+use crate::{B3Digest, Error};
+
+mod grpc;
+mod memory;
+mod sled;
+
+pub use self::grpc::GRPCBlobService;
+pub use self::memory::MemoryBlobService;
+pub use self::sled::SledBlobService;
+
+/// The base trait all BlobService services need to implement.
+/// 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 {
+    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: &B3Digest) -> Result<bool, Error>;
+
+    /// Request a blob from the store, by its content hash. Returns a Option<BlobReader>.
+    fn open_read(&self, digest: &B3Digest) -> 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>;
+}
+
+/// 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<B3Digest, Error>;
+}