2 files changed, 38 insertions, 0 deletions
diff --git a/src/Erebos/Storage/Head.hs b/src/Erebos/Storage/Head.hs
index 343669a..7e38af8 100644
--- a/src/Erebos/Storage/Head.hs
+++ b/src/Erebos/Storage/Head.hs
@@ -36,6 +36,7 @@ import Erebos.Object.Internal
 import Erebos.Storable.Internal
 import Erebos.Storage.Backend
 import Erebos.Storage.Internal
+import Erebos.Storage.Monad
 import Erebos.UUID qualified as U
 
 
diff --git a/src/Erebos/Storage/Monad.hs b/src/Erebos/Storage/Monad.hs
new file mode 100644
index 0000000..6af3ae1
--- /dev/null
+++ b/src/Erebos/Storage/Monad.hs
@@ -0,0 +1,37 @@
+module Erebos.Storage.Monad (
+    MonadStorage(..),
+    mloadKey,
+) where
+
+import Control.Monad.Except
+import Control.Monad.Reader
+
+import Erebos.Error
+import Erebos.Object.Internal
+import Erebos.Storable.Internal
+import Erebos.Storage.Key
+
+
+class Monad m => MonadStorage m where
+    getStorage :: m Storage
+    mstore :: Storable a => a -> m (Stored a)
+
+    default mstore :: MonadIO m => Storable a => a -> m (Stored a)
+    mstore x = do
+        st <- getStorage
+        wrappedStore st x
+
+    mstoreKey :: KeyPair sec pub => sec -> m ()
+    default mstoreKey :: (KeyPair sec pub, MonadIO m) => sec -> m ()
+    mstoreKey = liftIO . storeKey
+
+    mloadKeyMb :: KeyPair sec pub => Stored pub -> m (Maybe sec)
+    default mloadKeyMb :: (KeyPair sec pub, MonadIO m) => Stored pub -> m (Maybe sec)
+    mloadKeyMb = loadKeyMb
+
+mloadKey :: (KeyPair sec pub, MonadStorage m, MonadError e m, FromErebosError e) => Stored pub -> m sec
+mloadKey pub = maybe (throwOtherError $ "secret key not found for " <> show (storedRef pub)) return =<< mloadKeyMb pub
+
+
+instance MonadIO m => MonadStorage (ReaderT Storage m) where
+    getStorage = ask