ontoref-code/crates/ontoref-blobs/src/backend.rs
Jesús Pérez 234432856c
feat(daemon,ops): daemon surface + ontology-content implementation
Substantive changes across the crate tree (cargo check --workspace: clean):
- ontoref-daemon: UI handlers/pages, MCP surface, api, domain query delegation
- ontoref-ops: runtime
- ontoref-ontology / ontoref-ontology-content / oplog / triples / commit: supporting
- domains/rustelo: schema surface sync
2026-07-19 18:23:49 +01:00

101 lines
3.7 KiB
Rust

//! Pluggable blob-storage backend trait (D23).
//!
//! The runtime is parametric over any type implementing [`BlobBackend`].
//! [`LocalFilesystemBlobs`](crate::store::LocalFilesystemBlobs) is the
//! default impl shipped with the substrate — content-addressed files on
//! the local disk, no external dependencies. Alternative backends
//! (`S3Blobs`, `OciBlobs`) are placeholder modules behind feature flags;
//! their real implementations are deferred per the trigger-based
//! discipline (D23).
use crate::error::Result;
use crate::store::BlobId;
/// Pluggable content-addressed blob store.
///
/// Contract any backend MUST honour:
///
/// 1. `put(bytes)` returns the address `BlobId::from_bytes(bytes)` — addressing
/// is by blake3, identical across backends.
/// 2. `get(id)` returns the exact bytes that produced `id`, or an error.
/// Corrupted bytes MUST be rejected with [`crate::Error::Corrupt`].
/// 3. `exists(id)` is consistent with `get(id)`: it returns true iff a
/// subsequent `get(id)` would not return `NotFound`. It MUST NOT perform an
/// integrity check (use `get` for that).
/// 4. `list_prefix(prefix_hex)` returns every id whose hex representation
/// starts with `prefix_hex`. An empty `prefix_hex` returns every id known to
/// the backend.
pub trait BlobBackend {
/// Store `bytes` and return its content address.
///
/// # Errors
///
/// Backend-specific. The local-filesystem default returns IO errors
/// on write failure.
fn put(&self, bytes: &[u8]) -> Result<BlobId>;
/// Retrieve bytes by content address.
///
/// # Errors
///
/// - [`crate::Error::NotFound`] when the blob is absent.
/// - [`crate::Error::Corrupt`] when stored bytes do not hash to `id`.
/// - [`crate::Error::Io`] on transport failure.
fn get(&self, id: &BlobId) -> Result<Vec<u8>>;
/// Whether `id` is reachable (without integrity check).
fn exists(&self, id: &BlobId) -> bool;
/// List every known id whose hex representation starts with
/// `prefix_hex`.
///
/// # Errors
///
/// Backend-specific IO errors.
fn list_prefix(&self, prefix_hex: &str) -> Result<Vec<BlobId>>;
}
#[cfg(test)]
#[test]
fn local_filesystem() {
use crate::store::LocalFilesystemBlobs;
let tmp = tempfile::tempdir().expect("tempdir");
let backend: LocalFilesystemBlobs =
LocalFilesystemBlobs::open(tmp.path()).expect("open backend");
// put / get round trip
let bytes = b"hello blobs".to_vec();
let id = BlobBackend::put(&backend, &bytes).expect("put ok");
let fetched = BlobBackend::get(&backend, &id).expect("get ok");
assert_eq!(fetched, bytes);
// exists is true after put, false for an unknown id
assert!(BlobBackend::exists(&backend, &id));
let unknown = BlobId::from_bytes(b"never stored");
assert!(!BlobBackend::exists(&backend, &unknown));
// put is idempotent
let id_again = BlobBackend::put(&backend, &bytes).expect("re-put ok");
assert_eq!(id, id_again);
// list_prefix finds the blob by its hex prefix
let hex = id.to_hex();
let prefix = &hex[..4];
let found = BlobBackend::list_prefix(&backend, prefix).expect("list ok");
assert!(
found.iter().any(|x| x == &id),
"list_prefix({prefix}) must include the stored blob"
);
// empty prefix returns at least the stored blob
let all = BlobBackend::list_prefix(&backend, "").expect("list all ok");
assert!(all.iter().any(|x| x == &id));
// unknown prefix returns empty
let none = BlobBackend::list_prefix(&backend, "ffffffffff").expect("list ok");
assert!(
!none.iter().any(|x| x == &id),
"id with a different prefix must not be returned"
);
}