hasql/library/Hasql/Private/Encoders/Params.hs
2018-06-06 17:23:18 +08:00

32 lines
949 B
Haskell

module Hasql.Private.Encoders.Params where
import Hasql.Private.Prelude
import qualified Database.PostgreSQL.LibPQ as A
import qualified PostgreSQL.Binary.Encoding as B
import qualified Hasql.Private.Encoders.Value as C
import qualified Hasql.Private.PTI as D
import qualified Text.Builder as E
-- |
-- Encoder of some representation of a parameters product.
newtype Params a =
Params (Op (DList (A.Oid, A.Format, Bool -> Maybe ByteString, Text)) a)
deriving (Contravariant, Divisible, Decidable, Semigroup, Monoid)
value :: C.Value a -> Params a
value =
contramap Just . nullableValue
nullableValue :: C.Value a -> Params (Maybe a)
nullableValue (C.Value valueOID arrayOID encode render) =
Params $ Op $ \ input ->
let
D.OID _ pqOid format =
valueOID
encoder env =
fmap (B.encodingBytes . encode env) input
rendering =
maybe "null" (E.run . render) input
in pure (pqOid, format, encoder, rendering)