Added support for SHA3 hashed keys (in 8 varieties), when git-annex is built using the cryptonite library.

While cryptohash has SHA3 support, it has not been updated for the final
version of the spec. Note that cryptonite has not been ported to all arches
that cryptohash builds on yet.

Backend/Hash.hs

@@ -1,10 +1,12 @@
-{- git-tnnex hashing backends
+{- git-annex hashing backends
  -
- - Copyright 2011-2013 Joey Hess <id@joeyh.name>
+ - Copyright 2011-2015 Joey Hess <id@joeyh.name>
  -
  - Licensed under the GNU GPL version 3 or higher.
  -}
 
+{-# LANGUAGE CPP #-}
+
 module Backend.Hash (
 	backends,
 	testKeyBackend,
@@ -22,21 +24,30 @@ import qualified Build.SysConfig as SysConfig
 import qualified Data.ByteString.Lazy as L
 import Data.Char
 
-data Hash = SHAHash HashSize | SkeinHash HashSize | MD5Hash
+data Hash
+	= MD5Hash
+	| SHA1Hash
+	| SHA2Hash HashSize
+	| SHA3Hash HashSize
+	| SkeinHash HashSize
 type HashSize = Int
 
 {- Order is slightly significant; want SHA256 first, and more general
  - sizes earlier. -}
 hashes :: [Hash]
 hashes = concat 
-	[ map SHAHash [256, 1, 512, 224, 384]
+	[ map SHA2Hash [256, 512, 224, 384]
+#ifdef WITH_CRYPTONITE
+	, map SHA3Hash [256, 512, 224, 384]
+#endif
 	, map SkeinHash [256, 512]
+	, [SHA1Hash]
 	, [MD5Hash]
 	]
 
 {- The SHA256E backend is the default, so genBackendE comes first. -}
 backends :: [Backend]
-backends = map genBackendE hashes ++ map genBackend hashes
+backends = concatMap (\h -> [genBackendE h, genBackend h]) hashes
 
 genBackend :: Hash -> Backend
 genBackend hash = Backend
@@ -55,9 +66,11 @@ genBackendE hash = (genBackend hash)
 	}
 
 hashName :: Hash -> String
-hashName (SHAHash size) = "SHA" ++ show size
-hashName (SkeinHash size) = "SKEIN" ++ show size
 hashName MD5Hash = "MD5"
+hashName SHA1Hash = "SHA1"
+hashName (SHA2Hash size) = "SHA" ++ show size
+hashName (SHA3Hash size) = "SHA3_" ++ show size
+hashName (SkeinHash size) = "SKEIN" ++ show size
 
 hashNameE :: Hash -> String
 hashNameE hash = hashName hash ++ "E"
@@ -153,7 +166,15 @@ trivialMigrate oldkey newbackend afile
 hashFile :: Hash -> FilePath -> Integer -> Annex String
 hashFile hash file filesize = go hash
   where
-	go (SHAHash hashsize) = case shaHasher hashsize filesize of
+	go MD5Hash = use md5Hasher
+	go SHA1Hash = usehasher 1
+	go (SHA2Hash hashsize) = usehasher hashsize
+	go (SHA3Hash hashsize) = use (sha3Hasher hashsize)
+	go (SkeinHash hashsize) = use (skeinHasher hashsize)
+	
+	use hasher = liftIO $ hasher <$> L.readFile file
+	
+	usehasher hashsize = case shaHasher hashsize filesize of
 		Left sha -> use sha
 		Right (external, internal) -> do
 			v <- liftIO $ externalSHA external hashsize file
@@ -164,19 +185,15 @@ hashFile hash file filesize = go hash
 					-- fall back to internal since
 					-- external command failed
 					use internal
-	go (SkeinHash hashsize) = use (skeinHasher hashsize)
-	go MD5Hash = use md5Hasher
-	
-	use hasher = liftIO $ hasher <$> L.readFile file
 
 shaHasher :: HashSize -> Integer -> Either (L.ByteString -> String) (String, L.ByteString -> String)
 shaHasher hashsize filesize
 	| hashsize == 1 = use SysConfig.sha1 sha1
-	| hashsize == 256 = use SysConfig.sha256 sha256
-	| hashsize == 224 = use SysConfig.sha224 sha224
-	| hashsize == 384 = use SysConfig.sha384 sha384
-	| hashsize == 512 = use SysConfig.sha512 sha512
-	| otherwise = error $ "unsupported sha size " ++ show hashsize
+	| hashsize == 256 = use SysConfig.sha256 sha2_256
+	| hashsize == 224 = use SysConfig.sha224 sha2_224
+	| hashsize == 384 = use SysConfig.sha384 sha2_384
+	| hashsize == 512 = use SysConfig.sha512 sha2_512
+	| otherwise = error $ "unsupported SHA size " ++ show hashsize
   where
 	use Nothing hasher = Left $ usehasher hasher
 	use (Just c) hasher
@@ -189,11 +206,21 @@ shaHasher hashsize filesize
 		| otherwise = Right (c, usehasher hasher)
 	usehasher hasher = show . hasher
 
+sha3Hasher :: HashSize -> (L.ByteString -> String)
+sha3Hasher hashsize
+#ifdef WITH_CRYPTONITE
+	| hashsize == 256 = show . sha3_256
+	| hashsize == 224 = show . sha3_224
+	| hashsize == 384 = show . sha3_384
+	| hashsize == 512 = show . sha3_512
+#endif
+	| otherwise = error $ "unsupported SHA3 size " ++ show hashsize
+
 skeinHasher :: HashSize -> (L.ByteString -> String)
 skeinHasher hashsize 
 	| hashsize == 256 = show . skein256
 	| hashsize == 512 = show . skein512
-	| otherwise = error $ "unsupported skein size " ++ show hashsize
+	| otherwise = error $ "unsupported SKEIN size " ++ show hashsize
 
 md5Hasher :: L.ByteString -> String
 md5Hasher = show . md5
@@ -207,7 +234,7 @@ md5Hasher = show . md5
  -}
 testKeyBackend :: Backend
 testKeyBackend = 
-	let b = genBackendE (SHAHash 256)
+	let b = genBackendE (SHA2Hash 256)
 	in b { getKey = (fmap addE) <$$> getKey b } 
   where
 	addE k = k { keyName = keyName k ++ longext }