refactor adding neighbours

src/Hash2Pub/DHTProtocol.hs

@@ -64,9 +64,8 @@ import           Hash2Pub.FediChordTypes        (CacheEntry (..),
                                                  cacheGetNodeStateUnvalidated,
                                                  cacheLookup, cacheLookupPred,
                                                  cacheLookupSucc, getKeyID,
-                                                 localCompare, localCompare,
-                                                 rMapFromList, rMapLookupPred,
-                                                 rMapLookupSucc,
+                                                 localCompare, rMapFromList,
+                                                 rMapLookupPred, rMapLookupSucc,
                                                  setPredecessors, setSuccessors)
 import           Hash2Pub.ProtocolTypes
 

src/Hash2Pub/FediChord.hs

@@ -184,15 +184,14 @@ stabiliseThread :: LocalNodeStateSTM -> IO ()
 stabiliseThread nsSTM = do
     -- TODO: update successfully stabilised nodes in cache
     -- placeholder
-    stabiliseNeighbour nsSTM successors setSuccessors 1
+    stabiliseNeighbour nsSTM successors 1
     pure ()
   where
     stabiliseNeighbour :: LocalNodeStateSTM
                        -> (LocalNodeState -> [RemoteNodeState])
-                       -> ([RemoteNodeState] -> LocalNodeState -> LocalNodeState)
                        -> Int
                        -> IO (Either String ())
-    stabiliseNeighbour nsSTM neighbourGetter neighbourSetter neighbourNum = do
+    stabiliseNeighbour nsSTM neighbourGetter neighbourNum = do
         nsSnap <- readTVarIO nsSTM
         let chosenNode = maybe (Left "no such neighbour entry") Right $ atMay (neighbourGetter nsSnap) neighbourNum
         -- returning @Left@ signifies the need to try again with next from list
@@ -210,7 +209,7 @@ stabiliseThread nsSTM = do
     parseNeighbourResponse (Right (succs, preds)) = liftIO $ do
         atomically $ do
             newerNsSnap <- readTVar nsSTM
-            writeTVar nsSTM $ setPredecessors (predecessors newerNsSnap <> preds) . setSuccessors (successors newerNsSnap <> succs) $ newerNsSnap
+            writeTVar nsSTM $ addPredecessors preds . addSuccessors succs $ newerNsSnap
         pure ()
 
 -- periodically contact immediate successor and predecessor

src/Hash2Pub/FediChordTypes.hs

@@ -19,19 +19,21 @@ module Hash2Pub.FediChordTypes (
   , RingEntry(..)
   , RingMap(..)
   , HasKeyID
-                               , getKeyID
+  , getKeyID
   , rMapSize
   , rMapLookup
   , rMapLookupPred
   , rMapLookupSucc
   , addRMapEntry
   , addRMapEntryWith
+  , addPredecessors
+  , addSuccessors
   , takeRMapPredecessors
   , takeRMapSuccessors
   , deleteRMapEntry
   , setRMapEntries
-                               , rMapFromList
-                               , rMapToList
+  , rMapFromList
+  , rMapToList
   , cacheGetNodeStateUnvalidated
   , initCache
   , cacheEntries
@@ -238,13 +240,21 @@ instance Typeable a => Show (TQueue a) where
     show x = show (typeOf x)
 
 
--- | convenience function that updates the successors of a 'LocalNodeState'
+-- | convenience function that replaces the predecessors of a 'LocalNodeState' with the k closest nodes from the provided list
+setPredecessors :: [RemoteNodeState] -> LocalNodeState -> LocalNodeState
+setPredecessors preds ns = ns {predecessors = takeRMapPredecessors (getNid ns) (kNeighbours ns) . rMapFromList $ preds}
+
+-- | convenience function that replaces the successors of a 'LocalNodeState' with the k closest nodes from the provided list
 setSuccessors :: [RemoteNodeState] -> LocalNodeState -> LocalNodeState
 setSuccessors succs ns = ns {successors = takeRMapSuccessors (getNid ns) (kNeighbours ns) . rMapFromList $ succs}
 
--- | convenience function that updates the predecessors of a 'LocalNodeState'
-setPredecessors :: [RemoteNodeState] -> LocalNodeState -> LocalNodeState
-setPredecessors preds ns = ns {predecessors = takeRMapPredecessors (getNid ns) (kNeighbours ns) . rMapFromList $ preds}
+-- | sets the predecessors of a 'LocalNodeState' to the closest k nodes of the current predecessors and the provided list, combined
+addPredecessors :: [RemoteNodeState] -> LocalNodeState -> LocalNodeState
+addPredecessors preds ns = ns {predecessors = takeRMapPredecessors (getNid ns) (kNeighbours ns) . addRMapEntries preds . rMapFromList $ predecessors ns}
+
+-- | sets the successors of a 'LocalNodeState' to the closest k nodes of the current successors and the provided list, combined
+addSuccessors :: [RemoteNodeState] -> LocalNodeState -> LocalNodeState
+addSuccessors succs ns = ns {successors = takeRMapSuccessors (getNid ns) (kNeighbours ns) . addRMapEntries succs . rMapFromList $ successors ns}
 
 -- | Class for all types that can be identified via an EpiChord key.
 -- Used for restricting the types a 'RingMap' can store