US05-02: Orchestrate Album Upload Batches (#72)

photo_pipeline/services/hashing.py

@@ -24,7 +24,16 @@ _CHUNK = 1 << 20
 
 
 def sha256_file(path: Path | str) -> str:
-    digest = hashlib.sha256()
+    return _digest_file(path, hashlib.sha256())
+
+
+def sha1_file(path: Path | str) -> str:
+    """SHA-1 of the file bytes. Not an identity hash here — it is the checksum
+    Immich/immich-go use to recognise an asset they already hold (concept §8)."""
+    return _digest_file(path, hashlib.sha1())
+
+
+def _digest_file(path: Path | str, digest) -> str:
     with open(path, "rb") as handle:
         for chunk in iter(lambda: handle.read(_CHUNK), b""):
             digest.update(chunk)