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|
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE ScopedTypeVariables #-}
module Network.KRPC.Manager
( MonadKRPC (..)
, newManager
, query
, handler
) where
import Control.Applicative
import Control.Arrow
import Control.Concurrent
--import Control.Exception hiding (Handler)
import Control.Exception.Lifted as Lifted hiding (Handler)
import Control.Monad
import Control.Monad.Trans.Control
import Control.Monad.IO.Class
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 Network.KRPC.Message
import Network.KRPC.Method
import Network.Socket
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 m = SockAddr -> BValue -> m (BE.Result BValue)
type Handler m = (MethodName, HandlerBody m)
data Manager m = Manager
{ sock :: !Socket
, transactionCounter :: {-# UNPACK #-} !TransactionCounter
, pendingCalls :: {-# UNPACK #-} !PendingCalls
, handlers :: [Handler m]
}
class (MonadBaseControl IO m, MonadIO m) => MonadKRPC m where
getManager :: m (Manager a)
sockAddrFamily :: SockAddr -> Family
sockAddrFamily (SockAddrInet _ _ ) = AF_INET
sockAddrFamily (SockAddrInet6 _ _ _ _) = AF_INET6
sockAddrFamily (SockAddrUnix _ ) = AF_UNIX
seedTransaction :: Int
seedTransaction = 0
newManager :: SockAddr -> IO (Manager a)
newManager servAddr = do
sock <- bindServ
tran <- newIORef seedTransaction
calls <- newIORef M.empty
return $ Manager sock tran calls []
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
sendMessage :: MonadIO m => BEncode a => Socket -> SockAddr -> a -> m ()
sendMessage sock addr a =
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 ()
unregisterQuery cid ref = do
atomicModifyIORef' ref $ \ m -> (M.delete cid m, ())
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 m a b. (MonadKRPC 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
queryResponse ares
{-----------------------------------------------------------------------
-- Handlers
-----------------------------------------------------------------------}
handler :: forall m a b. (KRPC a b, MonadKRPC m)
=> (SockAddr -> a -> m b) -> Handler m
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 -> (Right . toBEncode) <$> body addr a
runHandler :: MonadKRPC m => HandlerBody m -> SockAddr -> KQuery -> m KResult
runHandler handler addr KQuery {..} = wrapper `Lifted.catch` failback
where
wrapper = ((`decodeError` queryId) +++ (`KResponse` queryId))
<$> handler addr queryArgs
failback e = return $ Left $ serverError e queryId
dispatchHandler :: MonadKRPC 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 handler -> runHandler handler addr q
{-----------------------------------------------------------------------
-- Listener
-----------------------------------------------------------------------}
handleQuery :: MonadKRPC m => KQuery -> SockAddr -> m ()
handleQuery q addr = do
Manager {..} <- getManager
res <- dispatchHandler q addr
sendMessage sock addr $ either toBEncode toBEncode res
handleResponse :: MonadKRPC m => KResult -> SockAddr -> m ()
handleResponse result addr = do
Manager {..} <- getManager
mcall <- undefined (addr, respId) pendingCalls
case mcall of
Nothing -> return ()
Just ares -> liftIO $ putMVar ares result
handleMessage :: MonadKRPC 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 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
|
