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|
{-# LANGUAGE BangPatterns #-}
{-# LANGUAGE OverloadedStrings #-}
module Network.Socket.ByteString.Lazy.Posix (
-- * Send data to a socket
send
, sendAll
) where
import qualified Data.ByteString.Lazy as L
import Data.ByteString.Unsafe (unsafeUseAsCStringLen)
import Foreign.Marshal.Array (allocaArray)
import Network.Socket.ByteString.IO (waitWhen0)
import Network.Socket.ByteString.Internal (c_writev)
import Network.Socket.Imports
import Network.Socket.Internal
import Network.Socket.Posix.IOVec (IOVec (IOVec))
import Network.Socket.Types
-- -----------------------------------------------------------------------------
-- Sending
send
:: Socket -- ^ Connected socket
-> L.ByteString -- ^ Data to send
-> IO Int64 -- ^ Number of bytes sent
send s lbs = do
let cs = take maxNumChunks (L.toChunks lbs)
len = length cs
siz <- withFdSocket s $ \fd -> allocaArray len $ \ptr ->
withPokes cs ptr $ \niovs ->
throwSocketErrorWaitWrite s "writev" $ c_writev fd ptr niovs
return $ fromIntegral siz
where
withPokes ss p f = loop ss p 0 0
where
loop (c:cs) q k !niovs
| k < maxNumBytes = unsafeUseAsCStringLen c $ \(ptr, len) -> do
poke q $ IOVec (castPtr ptr) (fromIntegral len)
loop cs
(q `plusPtr` sizeOf (IOVec nullPtr 0))
(k + fromIntegral len)
(niovs + 1)
| otherwise = f niovs
loop _ _ _ niovs = f niovs
maxNumBytes = 4194304 :: Int -- maximum number of bytes to transmit in one system call
maxNumChunks = 1024 :: Int -- maximum number of chunks to transmit in one system call
sendAll
:: Socket -- ^ Connected socket
-> L.ByteString -- ^ Data to send
-> IO ()
sendAll _ "" = return ()
sendAll s bs0 = loop bs0
where
loop bs = do
-- "send" throws an exception.
sent <- send s bs
waitWhen0 (fromIntegral sent) s
when (sent /= L.length bs) $ loop $ L.drop sent bs
|
