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|
-- |
-- Copyright : (c) Sam Truzjan 2013
-- License : BSD3
-- Maintainer : pxqr.sta@gmail.com
-- Stability : experimental
-- Portability : portable
--
-- Each P2P connection endpoint should keep track status of both
-- sides.
--
{-# LANGUAGE TemplateHaskell #-}
module Network.BitTorrent.Exchange.Status
( -- * Peer status
PeerStatus(..)
, choking
, interested
-- ** Query
, updateStatus
, statusUpdates
-- * Session status
, SessionStatus(..)
, clientStatus
, remoteStatus
-- ** Query
, canUpload
, canDownload
-- * Extra
, defaultUnchokeSlots
, defaultRechokeInterval
) where
import Control.Lens
import Data.Aeson.TH
import Data.Default
import Data.List as L
import Data.Maybe
import Data.Monoid
import Text.PrettyPrint as PP hiding ((<>))
import Text.PrettyPrint.Class
import Network.BitTorrent.Exchange.Message
{-----------------------------------------------------------------------
-- Peer status
-----------------------------------------------------------------------}
-- | Connections contain two bits of state on either end: choked or
-- not, and interested or not.
data PeerStatus = PeerStatus
{ -- | Choking is a notification that no data will be sent until
-- unchoking happens.
_choking :: !Bool
-- |
, _interested :: !Bool
} deriving (Show, Eq, Ord)
$(makeLenses ''PeerStatus)
$(deriveJSON defaultOptions { fieldLabelModifier = L.tail } ''PeerStatus)
instance Pretty PeerStatus where
pretty PeerStatus {..} =
pretty (Choking _choking) <+> "and" <+> pretty (Interested _interested)
-- | Connections start out choked and not interested.
instance Default PeerStatus where
def = PeerStatus True False
instance Monoid PeerStatus where
mempty = def
mappend a b = PeerStatus
{ _choking = _choking a && _choking b
, _interested = _interested a || _interested b
}
-- | Can be used to update remote peer status using incoming 'Status'
-- message.
updateStatus :: StatusUpdate -> PeerStatus -> PeerStatus
updateStatus (Choking b) = choking .~ b
updateStatus (Interested b) = interested .~ b
-- | Can be used to generate outcoming messages.
statusUpdates :: PeerStatus -> PeerStatus -> [StatusUpdate]
statusUpdates a b = catMaybes $
[ if _choking a == _choking b then Nothing
else Just $ Choking $ _choking b
, if _interested a == _interested b then Nothing
else Just $ Interested $ _interested b
]
{-----------------------------------------------------------------------
-- Session status
-----------------------------------------------------------------------}
-- | Status of the both endpoints.
data SessionStatus = SessionStatus
{ _clientStatus :: !PeerStatus
, _remoteStatus :: !PeerStatus
} deriving (Show, Eq)
$(makeLenses ''SessionStatus)
$(deriveJSON defaultOptions { fieldLabelModifier = L.tail } ''SessionStatus)
instance Pretty SessionStatus where
pretty SessionStatus {..} =
"this " <+> pretty _clientStatus $$
"remote" <+> pretty _remoteStatus
-- | Connections start out choked and not interested.
instance Default SessionStatus where
def = SessionStatus def def
-- | Can the client transfer to the remote peer?
canUpload :: SessionStatus -> Bool
canUpload SessionStatus {..}
= _interested _remoteStatus && not (_choking _clientStatus)
-- | Can the client transfer from the remote peer?
canDownload :: SessionStatus -> Bool
canDownload SessionStatus {..}
= _interested _clientStatus && not (_choking _remoteStatus)
-- | Indicates how many peers are allowed to download from the client
-- by default.
defaultUnchokeSlots :: Int
defaultUnchokeSlots = 4
-- |
defaultRechokeInterval :: Int
defaultRechokeInterval = 10 * 1000 * 1000
|
