import Control.Applicative ((<$>), liftA3)
import Data.Bits
import Data.Word (Word8)
-import Data.Map (Map(..), fromList, (!), mapWithKey)
+import Data.Map (Map(..), fromList, toList, (!), mapWithKey)
import FuncTorrent.Metainfo (Info(..), Metainfo(..))
import FuncTorrent.Utils (splitN)
-- todo - map with index to a new data structure (peers who have that piece amd state)
data PieceData = PieceData { peers :: [Peer] -- ^ list of peers who have this piece
, state :: PieceDlState -- ^ state of the piece from download perspective.
- , hash :: ByteString } -- ^ piece hash
+ , hash :: ByteString -- ^ piece hash
+ , len :: Integer } -- ^ piece length
-- which piece is with which peers
type PieceMap = Map Integer PieceData
-- Make the initial Piece map, with the assumption that no peer has the
-- piece and that every piece is pending download.
-mkPieceMap :: Integer -> ByteString -> PieceMap
-mkPieceMap numPieces pieceHash = fromList kvs
+mkPieceMap :: Integer -> ByteString -> Integer -> PieceMap
+mkPieceMap numPieces pieceHash pLen = fromList kvs
where kvs = [(i, PieceData { peers = []
, state = Pending
- , hash = h }) | (i, h) <- zip [0..numPieces] hashes]
+ , hash = h
+ , len = pLen })
+ | (i, h) <- zip [0..numPieces] hashes]
hashes = splitN (fromIntegral numPieces) pieceHash
havePiece :: PieceMap -> Integer -> Bool
-- loop1 :: shake hands with all peers, find out the pieces they have, form PieceData.
-- recvMsg :: Peer -> Handle -> Msg
msgLoop :: PeerState -> PieceMap -> IO ()
-msgLoop state pieceStatus = do
- -- if meInterested and he NOT Choking, pick a piece to download
- -- and send a requestmsg.
- let isMeInterested = meInterested state
- isHeChoking = heChoking state
- if (not isMeInterested && isHeChoking)
- then
- do
- let h = handle state
- sendMsg h InterestedMsg
- putStrLn $ "--> InterestedMsg to peer: " ++ show (peer state)
- msgLoop (state { meInterested = True }) pieceStatus
- else
- do
- msg <- getMsg (handle state)
- putStrLn $ "<-- " ++ show msg ++ "from peer: " ++ show (peer state)
- case msg of
- KeepAliveMsg -> do
- sendMsg (handle state) KeepAliveMsg
- msgLoop state pieceStatus
- BitFieldMsg bss -> do
- let pieceList = bitfieldToList (unpack bss)
- pieceStatus' = updatePieceAvailability pieceStatus (peer state) pieceList
- print pieceList
- -- for each pieceIndex in pieceList, make an entry in the pieceStatus
- -- map with pieceIndex as the key and modify the value to add the peer.
- -- download each of the piece in order
- msgLoop state pieceStatus'
- UnChokeMsg -> do
- msgLoop (state { heChoking = False }) pieceStatus
- _ -> do
- msgLoop state pieceStatus
+msgLoop state pieceStatus | meInterested state == False &&
+ heChoking state == True = do
+ -- if meInterested and he NOT Choking, pick a piece to download
+ -- and send a requestmsg.
+ let h = handle state
+ sendMsg h InterestedMsg
+ putStrLn $ "--> InterestedMsg to peer: " ++ show (peer state)
+ msgLoop (state { meInterested = True }) pieceStatus
+ | meInterested state == True &&
+ heChoking state == False =
+ case pickPiece pieceStatus of
+ Nothing -> putStrLn "Nothing to download"
+ Just workPiece -> do
+ let pLen = len (pieceStatus ! workPiece)
+ sendMsg (handle state) (RequestMsg workPiece 0 pLen)
+ putStrLn $ "--> RequestMsg for Piece " ++ (show workPiece) ++ "to peer: " ++ show (peer state)
+ msg <- getMsg (handle state)
+ putStrLn $ "<-- " ++ show msg ++ "from peer: " ++ show (peer state)
+ -- msgLoop state pieceStatus
+ | otherwise = do
+ msg <- getMsg (handle state)
+ putStrLn $ "<-- " ++ show msg ++ "from peer: " ++ show (peer state)
+ case msg of
+ KeepAliveMsg -> do
+ sendMsg (handle state) KeepAliveMsg
+ putStrLn $ "--> " ++ "KeepAliveMsg to peer: " ++ show (peer state)
+ msgLoop state pieceStatus
+ BitFieldMsg bss -> do
+ let pieceList = bitfieldToList (unpack bss)
+ pieceStatus' = updatePieceAvailability pieceStatus (peer state) pieceList
+ print pieceList
+ -- for each pieceIndex in pieceList, make an entry in the pieceStatus
+ -- map with pieceIndex as the key and modify the value to add the peer.
+ -- download each of the piece in order
+ msgLoop state pieceStatus'
+ UnChokeMsg -> do
+ msgLoop (state { heChoking = False }) pieceStatus
+ _ -> do
+ msgLoop state pieceStatus
+
+-- simple algorithm to pick piece.
+-- pick the first piece from 0 that is not downloaded yet.
+pickPiece :: PieceMap -> Maybe Integer
+pickPiece m =
+ let pieceList = toList m
+ allPending = filter (\(k, v) -> state v == Pending) pieceList
+ in
+ case allPending of
+ [] -> Nothing
+ ((i, _):_) -> Just i
updatePieceAvailability :: PieceMap -> Peer -> [Integer] -> PieceMap
updatePieceAvailability pieceStatus p pieceList =
, heChoking = True
, meInterested = False
, meChoking = True }
- pieceHash = (pieces (info m))
+ pieceHash = pieces (info m)
numPieces = (toInteger . (`quot` 20) . BC.length) pieceHash
- pieceStatus = mkPieceMap numPieces pieceHash
+ pLen = pieceLength (info m) :: Integer
+ pieceStatus = mkPieceMap numPieces pieceHash pLen
msgLoop state pieceStatus