From 30ba75b71f250d6080268513728df5ba3a2e8d61 Mon Sep 17 00:00:00 2001
From: Sam Truzjan <pxqr.sta@gmail.com>
Date: Sat, 22 Feb 2014 00:21:15 +0400
Subject: Unblock pending transactions at closeManager

---
 src/Network/BitTorrent/Tracker/RPC/UDP.hs | 30 +++++++++++++++++++++---------
 1 file changed, 21 insertions(+), 9 deletions(-)

(limited to 'src/Network/BitTorrent/Tracker/RPC/UDP.hs')

diff --git a/src/Network/BitTorrent/Tracker/RPC/UDP.hs b/src/Network/BitTorrent/Tracker/RPC/UDP.hs
index 0e592398..1ea47100 100644
--- a/src/Network/BitTorrent/Tracker/RPC/UDP.hs
+++ b/src/Network/BitTorrent/Tracker/RPC/UDP.hs
@@ -43,6 +43,7 @@ import Data.Text as T
 import Data.Text.Encoding
 import Data.Time
 import Data.Time.Clock.POSIX
+import Data.Traversable
 import Data.Typeable
 import Data.Word
 import Text.Read (readMaybe)
@@ -94,8 +95,10 @@ instance Default Options where
 -----------------------------------------------------------------------}
 
 type ConnectionCache     = Map SockAddr Connection
-type PendingTransactions = Map TransactionId (MVar Response)
-type PendingQueries      = Map SockAddr PendingTransactions
+
+type PendingResponse     = MVar (Either RpcException Response)
+type PendingTransactions = Map TransactionId PendingResponse
+type PendingQueries      = Map SockAddr      PendingTransactions
 
 data Manager = Manager
   { options         :: !Options
@@ -113,12 +116,18 @@ initManager opts = Manager opts
   <*> newMVar  M.empty
   <*> newEmptyMVar
 
+unblockAll :: PendingQueries -> IO ()
+unblockAll m = traverse (traverse unblock) m >> return ()
+  where
+    unblock ares = putMVar ares (Left ManagerClosed)
+
 resetState :: Manager -> IO ()
 resetState Manager {..} = do
-    writeIORef       connectionCache err
-    _ <-swapMVar     pendingResps    err
-    m <- tryTakeMVar listenerThread
-    case m of
+    writeIORef          connectionCache err
+    m    <- swapMVar    pendingResps    err
+    unblockAll m
+    mtid <- tryTakeMVar listenerThread
+    case mtid of
       Nothing -> return () -- thread killed by 'closeManager'
       Just _  -> return () -- thread killed by exception from 'listen'
     return ()
@@ -165,6 +174,9 @@ data RpcException
 
     -- | RPC succeed, but tracker respond with error code.
   | QueryFailed Text
+
+    -- | RPC manager closed while waiting for response.
+  | ManagerClosed
     deriving (Show, Typeable)
 
 instance Exception RpcException
@@ -365,7 +377,7 @@ isExpired Connection {..} = do
 --  Transactions
 -----------------------------------------------------------------------}
 
-register :: SockAddr -> TransactionId -> MVar Response
+register :: SockAddr -> TransactionId -> PendingResponse
          -> PendingQueries -> PendingQueries
 register addr tid ares = M.alter insertId addr
   where
@@ -399,7 +411,7 @@ commitTransaction Manager {..} addr tid resp =
     case M.lookup tid =<< M.lookup addr m of
       Nothing   -> return m -- tracker responded after 'cancelTransaction' fired
       Just ares -> do
-        putMVar ares resp
+        putMVar ares (Right resp)
         return $ unregister addr tid m
 
 -- | Abort transaction forcefully.
@@ -429,7 +441,7 @@ transaction mgr @ Manager {..} addr conn request = do
     performTransaction tid ares = do
       let trans = TransactionQ (connectionId conn) tid request
       BS.sendAllTo sock (encode trans) addr
-      takeMVar ares
+      takeMVar ares >>= either throwIO return
 
 {-----------------------------------------------------------------------
 --  Connection cache
-- 
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