Changed pgpSign to return a Maybe in case a signature cannot be made.

1 files changed, 5 insertions, 3 deletions

diff --git a/OpenPGP.hs b/OpenPGP.hs
index 7fef0b5..75054b3 100644
--- a/OpenPGP.hs
+++ b/OpenPGP.hs
@@ -10,6 +10,7 @@ import Data.OpenPGP.CryptoAPI (verify,fingerprint,sign,decryptSecretKey)
 import Data.Time.Clock.POSIX
 import Control.Applicative ( (<$>) )
 import Crypto.Random (newGenIO,SystemRandom)
+import ControlMaybe
 
 now = floor <$> Data.Time.Clock.POSIX.getPOSIXTime
 
@@ -32,11 +33,12 @@ pgpSign ::
     -> OpenPGP.SignatureOver -- ^ Data to sign, and optional signature packet
     -> OpenPGP.HashAlgorithm -- ^ HashAlgorithm to use in signature
     -> String                -- ^ KeyID of key to choose
-    -> IO OpenPGP.SignatureOver
-pgpSign seckeys dta hash_algo keyid = do
+    -> IO (Maybe OpenPGP.SignatureOver)
+pgpSign seckeys dta hash_algo keyid =
+    handleIO_ (return Nothing) $ do
     timestamp <- now
     g <- newGenIO :: IO SystemRandom
     let sigs = map (stampit timestamp) $ signatures_over dta
         dta' = dta { signatures_over = sigs }
     let (r,g') = sign seckeys dta' hash_algo keyid timestamp g
-    return r
+    return (Just r)