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{-# LANGUAGE CPP #-}
{-# LANGUAGE GADTs #-}
module Connection.Tox where
import qualified Connection as G
;import Connection (Manager (..), Policy (..))
import Control.Concurrent.STM
import Control.Monad
import Data.Dependent.Sum
import Data.Functor.Identity
import qualified Data.Map as Map
import Connection.Tox.Threads
import Network.Tox.NodeId
import PingMachine
import Text.Read
#ifdef THREAD_DEBUG
import Control.Concurrent.Lifted.Instrument
#else
import Control.Concurrent.Lifted
import GHC.Conc (labelThread)
#endif
import GHC.Conc (threadStatus,ThreadStatus(..))
data Parameters = Parameters
{ -- | Various Tox transports and clients.
-- toxTransports :: Tox
-- | Thread to be forked when a connection is established.
-- TODO: this function should accept relevant parameters.
onToxSession :: IO ()
}
data Key = Key NodeId{-me-} NodeId{-them-}
deriving (Eq,Ord)
instance Show Key where show = show . showKey_
{-
-- | A conneciton status that is tagged with a state type that is specific to
-- the status.
data Transient a where
IsDormant :: Transient ()
IsAwaitingDHTKey :: Transient ()
IsAcquiringIPAddress :: Transient ()
IsAcquiringCookie :: Transient ()
IsAwaitingHandshake :: Transient ()
IsAwaitingSessionPacket :: Transient ()
IsEstablished :: Transient ()
untag :: DSum Transient Identity -> G.Status ToxProgress
untag (IsDormant :=> _) = G.Dormant
untag (IsAwaitingDHTKey :=> _) = G.InProgress AwaitingDHTKey
untag (IsAcquiringIPAddress :=> _) = G.InProgress AcquiringIPAddress
untag (IsAcquiringCookie :=> _) = G.InProgress AcquiringCookie
untag (IsAwaitingHandshake :=> _) = G.InProgress AwaitingHandshake
untag (IsAwaitingSessionPacket :=> _) = G.InProgress AwaitingSessionPacket
untag (IsEstablished :=> _) = G.Established
-}
data StatefulTask st = StatefulTask
{ taskThread :: ThreadId
, taskState :: TVar st
}
launch :: String -> st -> ((st -> STM ()) -> IO ()) -> IO (StatefulTask st)
launch lbl st f = do
stvar <- newTVarIO st
tid <- forkIO (f $ writeTVar stvar)
labelThread tid lbl
return $ StatefulTask tid stvar
data SessionTasks = SessionTasks
{ accepting :: StatefulTask (G.Status ToxProgress)
, persuing :: StatefulTask (G.Status ToxProgress)
, refreshing :: StatefulTask (G.Status ToxProgress)
}
data SessionState = SessionState
{ connPolicy :: TVar Policy
, connPingLogic :: PingMachine
, sessionTasks :: TVar SessionTasks
-- , transient :: TVar (DSum Transient Identity)
}
sessionStatus :: SessionState -> G.Connection ToxProgress
sessionStatus st = G.Connection
{ G.connStatus = combinedStatus =<< readTVar (sessionTasks st)
, G.connPolicy = readTVar (connPolicy st)
, G.connPingLogic = connPingLogic st
}
combinedStatus :: SessionTasks -> STM (G.Status ToxProgress)
combinedStatus tasks = do
a <- readTVar (taskState $ accepting tasks)
p <- readTVar (taskState $ persuing tasks)
r <- readTVar (taskState $ refreshing tasks)
return $ maximum [a,p,r]
lookupForPolicyChange :: TVar (Map.Map Key SessionState)
-> Key -> Policy -> IO (Maybe SessionState)
lookupForPolicyChange conmap k policy = atomically $ do
cons <- readTVar conmap
fmap join $ forM (Map.lookup k cons) $ \st -> do
p <- readTVar (connPolicy st)
writeTVar (connPolicy st) policy
return $ do
guard $ p /= policy
return st
-- | This function will fork threads as necessary.
setToxPolicy :: Parameters
-> TVar (Map.Map Key SessionState)
-> Key
-> Policy
-> IO ()
setToxPolicy params conmap k policy = case policy of
TryingToConnect -> do
mst <- lookupForPolicyChange conmap k policy
forM_ mst $ \st -> do
let getPolicy = readTVar $ connPolicy st
tasks <- atomically $ readTVar (sessionTasks st)
--TODO This check to determine whether to launch the accepting thread
--is probably racey.
astat <- threadStatus (taskThread $ accepting tasks)
accepting <- if astat /= ThreadRunning
then launch ("accept:"++show k)
(G.InProgress $ toEnum 0)
$ acceptContact getPolicy _accept_methods
else return $ accepting tasks
persuing <- launch ("persue:"++show k)
(G.InProgress $ toEnum 0)
$ persueContact getPolicy _get_status _persue_methods
refreshing <- launch ("refresh:"++show k)
(G.InProgress $ toEnum 0)
$ freshenContact getPolicy _get_status _freshen_methods
atomically $ writeTVar (sessionTasks st)
$ SessionTasks accepting persuing refreshing
return ()
return ()
RefusingToConnect -> do -- disconnect or cancel any pending connection
mst <- lookupForPolicyChange conmap k policy
-- Since the 3 connection threads poll the current policy, they should
-- all terminate on their own.
--
-- Here we block until they finish.
forM_ mst $ \st -> do
atomically $ do
tasks <- readTVar (sessionTasks st)
a <- readTVar $ taskState (accepting tasks)
p <- readTVar $ taskState (persuing tasks)
r <- readTVar $ taskState (refreshing tasks)
case (a,p,r) of
(G.Dormant,G.Dormant,G.Dormant) -> return ()
_ -> retry
OpenToConnect -> do -- passively accept connections if they initiate.
mst <- lookupForPolicyChange conmap k policy
forM_ mst $ \st -> do
let getPolicy = readTVar $ connPolicy st
accept_thread <- launch ("accept:"++show k)
(G.InProgress $ toEnum 0)
$ acceptContact getPolicy _accept_methods
return ()
showKey_ :: Key -> String
showKey_ (Key me them) = show me ++ ":" ++ show them
stringToKey_ :: String -> Maybe Key
stringToKey_ s = let (xs,ys) = break (==':') s
in if null ys then Nothing
else do me <- readMaybe xs
them <- readMaybe (drop 1 ys)
return $ Key me them
toxManager :: Parameters -> IO (Manager ToxProgress Key)
toxManager params = do
conmap <- newTVarIO Map.empty
return Manager
{ setPolicy = setToxPolicy params conmap -- k -> Policy -> IO ()
, connections = fmap sessionStatus <$> readTVar conmap -- STM (Map k (Connection status))
, stringToKey = stringToKey_ -- String -> Maybe k
, showProgress = show -- status -> String
, showKey = showKey_ -- k -> String
}
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