1 files changed, 14 insertions, 0 deletions

diff --git a/src/Network/Tox/AggregateSession.hs b/src/Network/Tox/AggregateSession.hs
index d4497c48..26e7153a 100644
--- a/src/Network/Tox/AggregateSession.hs
+++ b/src/Network/Tox/AggregateSession.hs
@@ -9,6 +9,7 @@ module Network.Tox.AggregateSession
     , newAggregateSession
     , aggregateStatus
     , checkCompatible
+    , compatibleKeys
     , AddResult(..)
     , addSession
     , DelResult(..)
@@ -321,3 +322,16 @@ checkCompatible me them c = do
                     con:_        -> Just $ ncTheirPublicKey (singleSession con)   == them
                                            && (ncMyPublicKey $ singleSession con) == me
                     []           -> Nothing
+
+-- | Returns the local and remote keys that are compatible with this aggregate.
+-- If 'Nothing' Is returned, then either no key is compatible ('closeAll' was
+-- called) or all keys are compatible because no sessions have been associated.
+compatibleKeys :: AggregateSession -> STM (Maybe (PublicKey,PublicKey))
+compatibleKeys c = do
+    isclosed <- isClosedTMChan (contactChannel c)
+    imap <- readTVar (contactSession c)
+    return $ case IntMap.elems imap of
+                    _ | isclosed -> Nothing -- none.
+                    con:_        -> Just ( ncMyPublicKey $ singleSession con
+                                         , ncTheirPublicKey (singleSession con))
+                    []           -> Nothing -- any.