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|
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE DefaultSignatures #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE FunctionalDependencies #-}
{-# LANGUAGE FlexibleInstances #-}
module Network.KRPC.Manager
( MonadKRPC (..)
, Manager
, newManager
, closeManager
, query
, handler
, listener
, listen
) where
import Control.Applicative
import Control.Arrow
import Control.Concurrent
import Control.Concurrent.Lifted (fork)
import Control.Exception hiding (Handler)
import Control.Exception.Lifted as Lifted (catch)
import Control.Monad
import Control.Monad.Reader
import Control.Monad.Trans.Control
import Data.BEncode as BE
import Data.ByteString.Char8 as BC
import Data.ByteString.Lazy as BL
import Data.IORef
import Data.List as L
import Data.Map as M
import Data.Tuple
import Network.KRPC.Message
import Network.KRPC.Method
import Network.Socket hiding (listen)
import Network.Socket.ByteString as BS
type KResult = Either KError KResponse
type TransactionCounter = IORef Int
type CallId = (TransactionId, SockAddr)
type CallRes = MVar KResult
type PendingCalls = IORef (Map CallId CallRes)
type HandlerBody h = SockAddr -> BValue -> h (BE.Result BValue)
type Handler h = (MethodName, HandlerBody h)
data Manager h = Manager
{ sock :: !Socket
, transactionCounter :: {-# UNPACK #-} !TransactionCounter
, pendingCalls :: {-# UNPACK #-} !PendingCalls
, handlers :: [Handler h]
}
class (MonadBaseControl IO m, MonadIO m) => MonadKRPC h m | m -> h where
getManager :: m (Manager h)
default getManager :: MonadReader (Manager h) m => m (Manager h)
getManager = ask
liftHandler :: h a -> m a
instance (MonadBaseControl IO h, MonadIO h)
=> MonadKRPC h (ReaderT (Manager h) h) where
liftHandler = lift
sockAddrFamily :: SockAddr -> Family
sockAddrFamily (SockAddrInet _ _ ) = AF_INET
sockAddrFamily (SockAddrInet6 _ _ _ _) = AF_INET6
sockAddrFamily (SockAddrUnix _ ) = AF_UNIX
seedTransaction :: Int
seedTransaction = 0
newManager :: SockAddr -> [Handler h] -> IO (Manager h)
newManager servAddr handlers = do
sock <- bindServ
tran <- newIORef seedTransaction
calls <- newIORef M.empty
return $ Manager sock tran calls handlers
where
bindServ = do
let family = sockAddrFamily servAddr
sock <- socket family Datagram defaultProtocol
when (family == AF_INET6) $ do
setSocketOption sock IPv6Only 0
bindSocket sock servAddr
return sock
-- | Unblock all pending calls and close socket.
closeManager :: Manager m -> IO ()
closeManager Manager {..} = do
-- TODO unblock calls
close sock
sendMessage :: MonadIO m => BEncode a => Socket -> SockAddr -> a -> m ()
sendMessage sock addr a = do
liftIO $ sendManyTo sock (BL.toChunks (BE.encode a)) addr
{-----------------------------------------------------------------------
-- Client
-----------------------------------------------------------------------}
genTransactionId :: TransactionCounter -> IO TransactionId
genTransactionId ref = do
cur <- atomicModifyIORef' ref $ \ cur -> (succ cur, cur)
return $ BC.pack (show cur)
registerQuery :: CallId -> PendingCalls -> IO CallRes
registerQuery cid ref = do
ares <- newEmptyMVar
atomicModifyIORef' ref $ \ m -> (M.insert cid ares m, ())
return ares
unregisterQuery :: CallId -> PendingCalls -> IO (Maybe CallRes)
unregisterQuery cid ref = do
atomicModifyIORef' ref $ swap .
M.updateLookupWithKey (const (const Nothing)) cid
queryResponse :: BEncode a => CallRes -> IO a
queryResponse ares = do
res <- readMVar ares
case res of
Left e -> throwIO e
Right (KResponse {..}) ->
case fromBEncode respVals of
Left e -> throwIO (KError ProtocolError (BC.pack e) respId)
Right a -> return a
query :: forall h m a b. (MonadKRPC h m, KRPC a b) => SockAddr -> a -> m b
query addr params = do
Manager {..} <- getManager
liftIO $ do
tid <- genTransactionId transactionCounter
let Method name = method :: Method a b
let q = KQuery (toBEncode params) name tid
ares <- registerQuery (tid, addr) pendingCalls
sendMessage sock addr q
`onException` unregisterQuery (tid, addr) pendingCalls
res <- queryResponse ares
return res
{-----------------------------------------------------------------------
-- Handlers
-----------------------------------------------------------------------}
handler :: forall h a b. (KRPC a b, Monad h)
=> (SockAddr -> a -> h b) -> Handler h
handler body = (name, wrapper)
where
Method name = method :: Method a b
wrapper addr args =
case fromBEncode args of
Left e -> return $ Left e
Right a -> do
r <- body addr a
return $ Right $ toBEncode r
runHandler :: MonadKRPC h m => HandlerBody h -> SockAddr -> KQuery -> m KResult
runHandler h addr KQuery {..} = wrapper `Lifted.catch` failback
where
wrapper = ((`decodeError` queryId) +++ (`KResponse` queryId))
<$> liftHandler (h addr queryArgs)
failback e = return $ Left $ serverError e queryId
dispatchHandler :: MonadKRPC h m => KQuery -> SockAddr -> m KResult
dispatchHandler q @ KQuery {..} addr = do
Manager {..} <- getManager
case L.lookup queryMethod handlers of
Nothing -> return $ Left $ unknownMethod queryMethod queryId
Just h -> runHandler h addr q
{-----------------------------------------------------------------------
-- Listener
-----------------------------------------------------------------------}
handleQuery :: MonadKRPC h m => KQuery -> SockAddr -> m ()
handleQuery q addr = do
Manager {..} <- getManager
res <- dispatchHandler q addr
sendMessage sock addr $ either toBEncode toBEncode res
handleResponse :: MonadKRPC h m => KResult -> SockAddr -> m ()
handleResponse result addr = do
Manager {..} <- getManager
liftIO $ do
let resultId = either errorId respId result
mcall <- unregisterQuery (resultId, addr) pendingCalls
case mcall of
Nothing -> return ()
Just ares -> putMVar ares result
handleMessage :: MonadKRPC h m => KMessage -> SockAddr -> m ()
handleMessage (Q q) = handleQuery q
handleMessage (R r) = handleResponse (Right r)
handleMessage (E e) = handleResponse (Left e)
maxMsgSize :: Int
maxMsgSize = 64 * 1024
listener :: MonadKRPC h m => m ()
listener = do
Manager {..} <- getManager
forever $ do
(bs, addr) <- liftIO $ BS.recvFrom sock maxMsgSize
case BE.decode bs of
Left e -> liftIO $ sendMessage sock addr $ unknownMessage e
Right m -> handleMessage m addr
listen :: MonadKRPC h m => m ThreadId
listen = fork $ listener
|
