diff options
Diffstat (limited to 'Types.hs')
| -rw-r--r-- | Types.hs | 54 |
1 files changed, 16 insertions, 38 deletions
@@ -1,14 +1,14 @@ -{-# LANGUAGE GeneralizedNewtypeDeriving, DeriveGeneric, FlexibleInstances, OverloadedStrings #-} +{-# LANGUAGE DeriveGeneric, FlexibleInstances #-} -module Types where +module Types ( + module Types, + Val(..) +) where + +import Val -import Data.ByteString import GHC.Generics (Generic) import Data.Aeson -import Data.Aeson.Types -import qualified Codec.Binary.Base64 as B64 -import qualified Data.Text as T -import qualified Data.Text.Encoding as T -- | Things that the developer sees. data Seen = Seen @@ -35,9 +35,11 @@ instance FromJSON Entered -- to the Activity before this one. -- -- The Signature is over both the data in the activity, and its pointer. -data Activity a - = Activity a HashPointer Signature - | StartActivity a Signature +data Activity a = Activity + { activity :: a + , prevActivity :: (Maybe HashPointer) + , signature :: Signature + } deriving (Show, Generic) instance ToJSON (Activity Seen) @@ -45,13 +47,7 @@ instance FromJSON (Activity Seen) instance ToJSON (Activity Entered) instance FromJSON (Activity Entered) -activityContent :: Activity a -> a -activityContent (Activity a _ _) = a -activityContent (StartActivity a _) = a - -data Signature = Signature - { signature :: Val - } +newtype Signature = Signature Val deriving (Show, Generic) instance ToJSON Signature @@ -67,28 +63,10 @@ data HashPointer = HashPointer instance ToJSON HashPointer instance FromJSON HashPointer -data HashMethod = SHA256 +-- | We use SHA256. (SHA3 is included to future proof, and because it +-- improves the generated JSON.) +data HashMethod = SHA256 | SHA3 deriving (Show, Generic, Eq) instance ToJSON HashMethod instance FromJSON HashMethod - --- | Newtype of ByteString so we can have JSON instances without orphans. -newtype Val = Val { val :: ByteString } - deriving (Show, Generic, Eq, Monoid) - --- | JSON instances for Val, using base64 encoding. -instance ToJSON Val where - toJSON (Val b) = object [ "b" .= b64 b ] -instance FromJSON Val where - parseJSON (Object v) = Val <$> (unb64 =<< v .: "b") - parseJSON invalid = typeMismatch "ByteString" invalid - -b64 :: ByteString -> T.Text -b64 = T.decodeUtf8 . B64.encode - -unb64 :: Monad m => T.Text -> m ByteString -unb64 t = either - (\_ -> fail "bad base64 data") - return - ( B64.decode $ T.encodeUtf8 t) |