Change SASL handler computation type

This patch changes the SASL handler computation type from `ErrorT
AuthFailure (StateT Stream IO) ()' to `TMVar Stream -> IO (Either
XmppFailure (Maybe AuthFailure))' to better conform with the rest of
the API.

source/Network/Xmpp/Sasl.hs

@@ -67,7 +67,7 @@ xmppSasl :: [SaslHandler] -- ^ Acceptable authentication mechanisms and their
                        -- corresponding handlers
          -> TMVar Stream
          -> IO (Either XmppFailure (Maybe AuthFailure))
-xmppSasl handlers = withStream $ do
+xmppSasl handlers stream = (flip withStream stream) $ do
     -- Chooses the first mechanism that is acceptable by both the client and the
     -- server.
     mechanisms <- gets $ streamSaslMechanisms . streamFeatures
@@ -77,13 +77,7 @@ xmppSasl handlers = withStream $ do
             cs <- gets streamState
             case cs of
                 Closed -> return . Right $ Just AuthNoStream
-                _ -> do
-                       r <- runErrorT handler
-                       case r of
-                           Left ae -> return $ Right $ Just ae
-                           Right a -> do
-                               _ <- runErrorT $ ErrorT restartStream
-                               return $ Right $ Nothing
+                _ -> lift $ handler stream
 
 -- | Authenticate to the server using the first matching method and bind a
 -- resource.

source/Network/Xmpp/Sasl/Mechanisms/DigestMd5.hs

@@ -37,7 +37,7 @@ import           Network.Xmpp.Sasl.Common
 import           Network.Xmpp.Sasl.StringPrep
 import           Network.Xmpp.Sasl.Types
 
-
+import           Control.Concurrent.STM
 
 xmppDigestMd5 ::  Text -- ^ Authentication identity (authzid or username)
                -> Maybe Text -- ^ Authorization identity (authcid)
@@ -127,6 +127,25 @@ digestMd5 :: Text -- ^ Authentication identity (authcid or username)
           -> Maybe Text -- ^ Authorization identity (authzid)
           -> Text -- ^ Password
           -> SaslHandler
-digestMd5 authcid authzid password = ( "DIGEST-MD5"
-                                     , xmppDigestMd5 authcid authzid password
-                                     )
+digestMd5 authcid authzid password =
+    ( "DIGEST-MD5"
+    , \stream -> do
+        stream_ <- atomically $ readTMVar stream
+        r <- runErrorT $ do
+          -- Alrighty! The problem here is that `scramSha1' runs in the
+          -- `IO (Either XmppFailure (Maybe AuthFailure))' monad, while we need
+          -- to call an `ErrorT AuthFailure (StateT Stream IO) ()' calculation.
+          -- The key is to use `mapErrorT', which is called with the following
+          -- ypes:
+          -- 
+          -- mapErrorT :: (StateT Stream IO (Either AuthError ()) -> IO (Either AuthError ()))
+          --           -> ErrorT AuthError (StateT Stream IO) ()
+          --           -> ErrorT AuthError IO ()
+          mapErrorT
+            (\s -> runStateT s stream_ >>= \(r, _) -> return r)
+            (xmppDigestMd5 authcid authzid password)
+        case r of
+          Left (AuthStreamFailure e) -> return $ Left e
+          Left e -> return $ Right $ Just e
+          Right () -> return $ Right $ Nothing
+    )

source/Network/Xmpp/Sasl/Mechanisms/Plain.hs

@@ -46,6 +46,8 @@ import qualified Data.Text as Text
 import           Network.Xmpp.Sasl.Common
 import           Network.Xmpp.Sasl.Types
 
+import           Control.Concurrent.STM
+
 -- TODO: stringprep
 xmppPlain :: Text.Text -- ^ Password
           -> Maybe Text.Text -- ^ Authorization identity (authzid)
@@ -77,4 +79,27 @@ plain :: Text.Text -- ^ authentication ID (username)
       -> Maybe Text.Text -- ^ authorization ID
       -> Text.Text -- ^ password
       -> SaslHandler
-plain authcid authzid passwd = ("PLAIN", xmppPlain authcid authzid passwd)
+plain authcid authzid passwd =
+    ( "PLAIN"
+    , \stream -> do
+        stream_ <- atomically $ readTMVar stream
+        r <- runErrorT $ do
+          -- Alrighty! The problem here is that `scramSha1' runs in the
+          -- `IO (Either XmppFailure (Maybe AuthFailure))' monad, while we need
+          -- to call an `ErrorT AuthFailure (StateT Stream IO) ()' calculation.
+          -- The key is to use `mapErrorT', which is called with the following
+          -- ypes:
+          -- 
+          -- mapErrorT :: (StateT Stream IO (Either AuthError ()) -> IO (Either AuthError ()))
+          --           -> ErrorT AuthError (StateT Stream IO) ()
+          --           -> ErrorT AuthError IO ()
+          mapErrorT
+            (\s -> runStateT s stream_ >>= \(r, _) -> return r)
+            (xmppPlain authcid authzid passwd)
+        case r of
+          Left (AuthStreamFailure e) -> return $ Left e
+          Left e -> return $ Right $ Just e
+          Right () -> return $ Right $ Nothing
+    )
+
+

source/Network/Xmpp/Sasl/Mechanisms/Scram.hs

@@ -31,8 +31,8 @@ import           Network.Xmpp.Sasl.StringPrep
 import           Network.Xmpp.Sasl.Types
 import           Network.Xmpp.Types
 
-
 import           Control.Monad.State.Strict
+import           Control.Concurrent.STM
 
 -- | A nicer name for undefined, for use as a dummy token to determin
 -- the hash function to use
@@ -164,6 +164,24 @@ scramSha1 :: Text.Text  -- ^ username
           -> Text.Text   -- ^ password
           -> SaslHandler
 scramSha1 authcid authzid passwd =
-    ("SCRAM-SHA-1"
-    , scram (hashToken :: Crypto.SHA1) authcid authzid passwd
+    ( "SCRAM-SHA-1"
+    , \stream -> do
+        stream_ <- atomically $ readTMVar stream
+        r <- runErrorT $ do
+          -- Alrighty! The problem here is that `scramSha1' runs in the
+          -- `IO (Either XmppFailure (Maybe AuthFailure))' monad, while we need
+          -- to call an `ErrorT AuthFailure (StateT Stream IO) ()' calculation.
+          -- The key is to use `mapErrorT', which is called with the following
+          -- ypes:
+          -- 
+          -- mapErrorT :: (StateT Stream IO (Either AuthError ()) -> IO (Either AuthError ()))
+          --           -> ErrorT AuthError (StateT Stream IO) ()
+          --           -> ErrorT AuthError IO ()
+          mapErrorT
+            (\s -> runStateT s stream_ >>= \(r, _) -> return r)
+            (scram (hashToken :: Crypto.SHA1) authcid authzid passwd)
+        case r of
+          Left (AuthStreamFailure e) -> return $ Left e
+          Left e -> return $ Right $ Just e
+          Right () -> return $ Right $ Nothing
     )

source/Network/Xmpp/Sasl/Types.hs

@@ -6,6 +6,7 @@ import           Control.Monad.State.Strict
 import           Data.ByteString(ByteString)
 import qualified Data.Text as Text
 import           Network.Xmpp.Types
+import           Control.Concurrent.STM
 
 data AuthFailure = AuthXmlFailure
                | AuthNoAcceptableMechanism [Text.Text] -- ^ Wraps mechanisms
@@ -32,4 +33,4 @@ type Pairs = [(ByteString, ByteString)]
 -- | Tuple defining the SASL Handler's name, and a SASL mechanism computation.
 -- The SASL mechanism is a stateful @Stream@ computation, which has the
 -- possibility of resulting in an authentication error.
-type SaslHandler = (Text.Text, ErrorT AuthFailure (StateT Stream IO) ())
+type SaslHandler = (Text.Text, (TMVar Stream -> IO (Either XmppFailure (Maybe AuthFailure))))