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|
-- |
-- Module : Crypto.Error.Types
-- License : BSD-style
-- Maintainer : Vincent Hanquez <vincent@snarc.org>
-- Stability : stable
-- Portability : Good
--
-- Cryptographic Error enumeration and handling
--
{-# LANGUAGE DeriveDataTypeable #-}
module Crypto.Error.Types
( CryptoError(..)
, CryptoFailable(..)
, throwCryptoErrorIO
, throwCryptoError
, onCryptoFailure
, eitherCryptoError
, maybeCryptoError
) where
import qualified Control.Exception as E
import Data.Data
import Crypto.Internal.Imports
-- | Enumeration of all possible errors that can be found in this library
data CryptoError =
-- symmetric cipher errors
CryptoError_KeySizeInvalid
| CryptoError_IvSizeInvalid
| CryptoError_AEADModeNotSupported
-- public key cryptography error
| CryptoError_SecretKeySizeInvalid
| CryptoError_SecretKeyStructureInvalid
| CryptoError_PublicKeySizeInvalid
| CryptoError_SharedSecretSizeInvalid
-- Message authentification error
| CryptoError_MacKeyInvalid
| CryptoError_AuthenticationTagSizeInvalid
deriving (Show,Eq,Enum,Data,Typeable)
instance E.Exception CryptoError
-- | A simple Either like type to represent a computation that can fail
--
-- 2 possibles values are:
--
-- * 'CryptoPassed' : The computation succeeded, and contains the result of the computation
--
-- * 'CryptoFailed' : The computation failed, and contains the cryptographic error associated
--
data CryptoFailable a =
CryptoPassed a
| CryptoFailed CryptoError
deriving (Show)
instance Eq a => Eq (CryptoFailable a) where
(==) (CryptoPassed a) (CryptoPassed b) = a == b
(==) (CryptoFailed e1) (CryptoFailed e2) = e1 == e2
(==) _ _ = False
instance Functor CryptoFailable where
fmap f (CryptoPassed a) = CryptoPassed (f a)
fmap _ (CryptoFailed r) = CryptoFailed r
instance Applicative CryptoFailable where
pure a = CryptoPassed a
(<*>) fm m = fm >>= \p -> m >>= \r2 -> return (p r2)
instance Monad CryptoFailable where
return a = CryptoPassed a
(>>=) m1 m2 = do
case m1 of
CryptoPassed a -> m2 a
CryptoFailed e -> CryptoFailed e
-- | Throw an CryptoError as exception on CryptoFailed result,
-- otherwise return the computed value
throwCryptoErrorIO :: CryptoFailable a -> IO a
throwCryptoErrorIO (CryptoFailed e) = E.throwIO e
throwCryptoErrorIO (CryptoPassed r) = return r
-- | Same as 'throwCryptoErrorIO' but throw the error asynchronously.
throwCryptoError :: CryptoFailable a -> a
throwCryptoError (CryptoFailed e) = E.throw e
throwCryptoError (CryptoPassed r) = r
-- | Simple 'either' like combinator for CryptoFailable type
onCryptoFailure :: (CryptoError -> r) -> (a -> r) -> CryptoFailable a -> r
onCryptoFailure onError _ (CryptoFailed e) = onError e
onCryptoFailure _ onSuccess (CryptoPassed r) = onSuccess r
-- | Transform a CryptoFailable to an Either
eitherCryptoError :: CryptoFailable a -> Either CryptoError a
eitherCryptoError (CryptoFailed e) = Left e
eitherCryptoError (CryptoPassed a) = Right a
-- | Transform a CryptoFailable to a Maybe
maybeCryptoError :: CryptoFailable a -> Maybe a
maybeCryptoError (CryptoFailed _) = Nothing
maybeCryptoError (CryptoPassed r) = Just r
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