Network rewrite with data request and ack

Packet header is now composed of individual header items, which can be
combined in various ways. Received data is properly acknowledged and
missing objects can be requested using hashes.

1 files changed, 11 insertions, 5 deletions

diff --git a/src/Storage/Internal.hs b/src/Storage/Internal.hs
index 400af8f..76a3945 100644
--- a/src/Storage/Internal.hs
+++ b/src/Storage/Internal.hs
@@ -63,6 +63,9 @@ instance ByteArrayAccess (Ref' c) where
     length (Ref _ dgst) = BA.length dgst
     withByteArray (Ref _ dgst) = BA.withByteArray dgst
 
+refStorage :: Ref' c -> Storage' c
+refStorage (Ref st _) = st
+
 refDigest :: Ref' c -> RefDigest
 refDigest (Ref _ dgst) = dgst
 
@@ -80,21 +83,24 @@ data Head' c = Head String (Ref' c)
     deriving (Show)
 
 
+type Complete = Identity
+type Partial = Either RefDigest
+
 class (Traversable compl, Monad compl) => StorageCompleteness compl where
     type LoadResult compl a :: *
     returnLoadResult :: compl a -> LoadResult compl a
     ioLoadBytes :: Ref' compl -> IO (compl BL.ByteString)
 
-instance StorageCompleteness Identity where
-    type LoadResult Identity a = a
+instance StorageCompleteness Complete where
+    type LoadResult Complete a = a
     returnLoadResult = runIdentity
     ioLoadBytes ref@(Ref st dgst) = maybe (error $ "Ref not found in complete storage: "++show ref) Identity
         <$> ioLoadBytesFromStorage st dgst
 
-instance StorageCompleteness Maybe where
-    type LoadResult Maybe a = Maybe a
+instance StorageCompleteness Partial where
+    type LoadResult Partial a = Either RefDigest a
     returnLoadResult = id
-    ioLoadBytes (Ref st dgst) = ioLoadBytesFromStorage st dgst
+    ioLoadBytes (Ref st dgst) = maybe (Left dgst) Right <$> ioLoadBytesFromStorage st dgst
 
 ioLoadBytesFromStorage :: Storage' c -> RefDigest -> IO (Maybe BL.ByteString)
 ioLoadBytesFromStorage st dgst = loadCurrent st >>=