Initial commit

bundled/Network/ONCRPC/XDR/Opaque.hs

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+-- |Marshalling values into and out of 'Network.ONCRPC.XDR.Types.Opaque' byte strings.
+-- Not really part of XDR, but convenient way to avoid many conversion functions.
+
+{-# LANGUAGE DefaultSignatures #-}
+module Network.ONCRPC.XDR.Opaque
+  ( Opaqued(..)
+  , unopacify'
+  , toOpaque
+  , toOpaque'
+  , fromOpaque
+  , fromOpaque'
+  ) where
+
+import           Data.ByteString (ByteString)
+
+import           Network.ONCRPC.XDR.Array
+import           Network.ONCRPC.XDR.Serial
+
+-- |Values that can be stored in an 'Network.ONCRPC.XDR.Types.Opaque' 'ByteString'.
+-- The default implementation allows (re-)embedding of XDR-encoded data, such as with 'RPC.Opaque_auth'.
+class Opaqued a where
+  opacify :: a -> ByteString
+  default opacify :: XDR a => a -> ByteString
+  opacify = xdrSerialize
+  unopacify :: MonadFail m => ByteString -> m a
+  default unopacify :: (XDR a, MonadFail m) => ByteString -> m a
+  unopacify = either fail return . xdrDeserialize
+
+unopacify' :: Opaqued a => ByteString -> a
+unopacify' = either error id . unopacify
+
+toOpaque :: (Opaqued a, KnownOrdering o, KnownNat n) => a -> Maybe (LengthArray o n ByteString)
+toOpaque = lengthArray . opacify
+
+toOpaque' :: (Opaqued a, KnownOrdering o, KnownNat n) => a -> LengthArray o n ByteString
+toOpaque' = lengthArray' . opacify
+
+fromOpaque :: (Opaqued a, MonadFail m) => LengthArray o n ByteString -> m a
+fromOpaque = unopacify . unLengthArray
+
+fromOpaque' :: Opaqued a => LengthArray o n ByteString -> a
+fromOpaque' = unopacify' . unLengthArray