2 files changed, 7 insertions, 16 deletions
diff --git a/iserv/src/Remote/Message.hs b/iserv/src/Remote/Message.hs
index faef45dcab..f1745301ba 100644
--- a/iserv/src/Remote/Message.hs
+++ b/iserv/src/Remote/Message.hs
@@ -3,29 +3,19 @@
 module Remote.Message
   ( SlaveMessage(..)
   , SlaveMsg(..)
-  , sha256sum
   , putSlaveMessage
   , getSlaveMessage )
 where
 
+import GHC.Fingerprint (Fingerprint)
 import Data.Binary
-import Data.ByteString as BS (ByteString, readFile)
-
-import Crypto.Hash
-
-type Sha256Hash = String
-
-sha256 :: ByteString -> Digest SHA256
-sha256 = hash
-
-sha256sum :: FilePath -> IO Sha256Hash
-sha256sum path = (show . sha256) <$> BS.readFile path
+import Data.ByteString (ByteString)
 
 -- | A @SlaveMessage a@ is message from the iserv process on the
 -- target, requesting something from the Proxy of with result type @a@.
 data SlaveMessage a where
   -- sends either a new file, or nothing if the file is acceptable.
-  Have     :: FilePath -> Sha256Hash -> SlaveMessage (Maybe ByteString)
+  Have     :: FilePath -> Fingerprint -> SlaveMessage (Maybe ByteString)
   Missing  :: FilePath -> SlaveMessage ByteString
   Done     :: SlaveMessage ()
 
diff --git a/iserv/src/Remote/Slave.hs b/iserv/src/Remote/Slave.hs
index 2d47a346c6..e7ff3f2874 100644
--- a/iserv/src/Remote/Slave.hs
+++ b/iserv/src/Remote/Slave.hs
@@ -19,6 +19,7 @@ import GHCi.Message (Pipe(..), Msg(..), Message(..), readPipe, writePipe)
 import Foreign.C.String
 
 import Data.Binary
+import GHC.Fingerprint (getFileHash)
 
 import qualified Data.ByteString as BS
 
@@ -59,16 +60,16 @@ startSlave' verbose base_path port = do
 --
 -- If we however already have the requested file we need to make
 -- sure that this file is the same one ghc sees. Hence we
--- calculate the sha256sum of the file and send it back to the
+-- calculate the Fingerprint of the file and send it back to the
 -- host for comparison. The proxy will then send back either @Nothing@
--- indicating that the file on the host has the same sha256sum, or
+-- indicating that the file on the host has the same Fingerprint, or
 -- Maybe ByteString containing the payload to replace the existing
 -- file with.
 handleLoad :: Pipe -> FilePath -> FilePath -> IO ()
 handleLoad pipe path localPath = do
   exists <- doesFileExist localPath
   if exists
-    then sha256sum localPath >>= \hash -> proxyCall (Have path hash) >>= \case
+    then getFileHash localPath >>= \hash -> proxyCall (Have path hash) >>= \case
       Nothing -> return ()
       Just bs -> BS.writeFile localPath bs
     else do