add `Value` instance for `readFile`

1 files changed, 10 insertions, 1 deletions

diff --git a/src/Store/Store.hs b/src/Store/Store.hs
index e0bbdfb..1ec59ef 100644
--- a/src/Store/Store.hs
+++ b/src/Store/Store.hs
@@ -13,13 +13,14 @@ where
 
 import Bindings.Libgit2 qualified as B
 import Control.Arrow (first)
-import Control.Exception (Exception, finally)
+import Control.Exception (Exception, finally, throw)
 import Control.Monad (when)
 import Control.Monad.Catch (MonadCatch, MonadMask, MonadThrow, throwM)
 import Control.Monad.Reader (MonadReader, ReaderT, ask, runReaderT)
 import Control.Monad.State (MonadState, StateT, evalStateT, get, modify)
 import Control.Monad.Trans (MonadIO, MonadTrans, lift, liftIO)
 import Control.Monad.Trans.Resource (MonadResource, runResourceT)
+import Data.Aeson qualified as J
 import Data.ByteString qualified as B
 import Data.ByteString.Lazy qualified as LB
 import Data.ByteString.UTF8 qualified as B
@@ -146,6 +147,11 @@ data InappropriateType = InappropriateType String FilePath
 
 instance Exception InappropriateType
 
+data DecodeException = DecodeException String
+  deriving (Show)
+
+instance Exception DecodeException
+
 class Readable a where
   readFile :: FilePath -> StoreM a
 
@@ -158,6 +164,9 @@ instance Readable B.ByteString where
 instance Readable LB.ByteString where
   readFile = readFile' G.catBlobLazy
 
+instance Readable J.Value where
+  readFile = fmap (either (throw . DecodeException) id . J.eitherDecode) . readFile
+
 readFile' ::
   (G.BlobOid GB.LgRepo -> ReaderT GB.LgRepo IO a) ->
   FilePath ->