From 6ebe91b686ca8bef893f9a3dd704e45c04124b8f Mon Sep 17 00:00:00 2001
From: Joe Crayne <joe@jerkface.net>
Date: Wed, 16 Jan 2019 22:53:41 -0500
Subject: kademlia: support for async search queries.

---
 src/Network/Kademlia/Search.hs | 32 +++++++++++++++++++-------------
 1 file changed, 19 insertions(+), 13 deletions(-)

(limited to 'src/Network/Kademlia')

diff --git a/src/Network/Kademlia/Search.hs b/src/Network/Kademlia/Search.hs
index e87a8618..1be1afc1 100644
--- a/src/Network/Kademlia/Search.hs
+++ b/src/Network/Kademlia/Search.hs
@@ -31,7 +31,8 @@ import GHC.Conc                  (labelThread)
 data Search nid addr tok ni r = Search
     { searchSpace        :: KademliaSpace nid ni
     , searchNodeAddress  :: ni -> addr
-    , searchQuery        :: nid -> ni -> IO (Maybe ([ni], [r], Maybe tok))
+    , searchQuery        :: Either (nid -> ni -> IO (Maybe ([ni], [r], Maybe tok)))
+                                   (nid -> ni -> (Maybe ([ni],[r],Maybe tok) -> IO ()) -> IO ())
     , searchAlpha        :: Int -- α = 8
       -- | 'searchK' should be larger than 'searchAlpha'.  How much larger depends on
       -- how fast the queries are.  For Tox's much slower onion-routed queries, we
@@ -112,7 +113,7 @@ reset nearestNodes qsearch target st = do
     writeTVar (searchPendingCount st) 0
     return st
 
-sendQuery :: forall addr nid tok ni r.
+sendAsyncQuery :: forall addr nid tok ni r.
             ( Ord addr
             , PSQKey nid
             , PSQKey ni
@@ -123,15 +124,22 @@ sendQuery :: forall addr nid tok ni r.
             -> (r -> STM Bool) -- ^ return False to terminate the search.
             -> SearchState nid addr tok ni r
             -> Binding ni nid
+            -> TaskGroup
             -> IO ()
-sendQuery Search{..} searchTarget searchResult sch@SearchState{..} (ni :-> d) = do
-    myThreadId >>= flip labelThread ("searchQuery." ++ show searchTarget)
-    reply <- searchQuery searchTarget ni `catchIOError` const (return Nothing)
-    -- (ns,rs)
-    let tok = error "TODO: token"
-    atomically $ do
-        modifyTVar searchPendingCount pred
-        maybe (return ()) go reply
+sendAsyncQuery Search{..} searchTarget searchResult sch@SearchState{..} (ni :-> d) g =
+    case searchQuery of
+        Left blockingQuery ->
+          forkTask g "searchQuery" $ do
+            myThreadId >>= flip labelThread ("searchQuery." ++ show searchTarget)
+            reply <- blockingQuery searchTarget ni `catchIOError` const (return Nothing)
+            atomically $ do
+                modifyTVar searchPendingCount pred
+                maybe (return ()) go reply
+        Right nonblockingQuery -> do
+            nonblockingQuery searchTarget ni $ \reply ->
+                atomically $ do
+                    modifyTVar searchPendingCount pred
+                    maybe (return ()) go reply
  where
     go (ns,rs,tok) = do
         vs <- readTVar searchVisited
@@ -221,9 +229,7 @@ searchLoop sch@Search{..} target result s@SearchState{..} = do
                         modifyTVar searchVisited $ Set.insert (searchNodeAddress ni)
                         modifyTVar searchPendingCount succ
                         return $ do
-                            forkTask g
-                                     "searchQuery"
-                                     $ sendQuery sch target result s (ni :-> d)
+                            sendAsyncQuery sch target result s (ni :-> d) g
                             again
                 _ -> -- Otherwise, we are finished.
                      do check (cnt == 0)
-- 
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