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{-# LANGUAGE DeriveDataTypeable #-}
{-# LANGUAGE DeriveGeneric #-}
{-# LANGUAGE ExistentialQuantification #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE GeneralizedNewtypeDeriving #-}
{-# LANGUAGE LambdaCase #-}
{-# LANGUAGE NamedFieldPuns #-}
{-# LANGUAGE NondecreasingIndentation #-}
module Announcer.Tox where
-- , AnnounceMethod(..)
-- , schedule
import Announcer
import qualified Data.MinMaxPSQ as MM
import Data.Wrapper.PSQ as PSQ
import InterruptibleDelay
import Network.Kademlia.Routing as R
import Network.Kademlia.Search
import Control.Concurrent.Lifted.Instrument
import Control.Concurrent.STM
import Control.Monad
import Data.Hashable
import Data.Maybe
import Data.Ord
import Data.Time.Clock.POSIX
import System.IO
announceK :: Int
announceK = 8
data AnnounceState = forall nid addr tok ni r. AnnounceState
{ aState :: SearchState nid addr tok ni r
, aStoringNodes :: TVar (MM.MinMaxPSQ ni (Down POSIXTime))
}
-- | This type specifies an item that can be announced on appropriate nodes in
-- a Kademlia network.
data AnnounceMethod r = forall nid ni sr addr tok a.
( Show nid
, Hashable nid
, Hashable ni
, Ord addr
, Ord nid
, Ord ni
) => AnnounceMethod
{ aSearch :: Search nid addr tok ni sr
-- ^ This is the Kademlia search to run repeatedly to find the
-- nearby nodes. A new search is started whenever one is not
-- already in progress at announce time. Repeated searches are
-- likely to finish faster than the first since nearby nodes
-- are not discarded.
, aPublish :: Either (r -> sr -> IO ())
(r -> tok -> Maybe ni -> IO (Maybe a))
-- ^ The action to perform when we find nearby nodes. The
-- destination node is given as a Maybe so that methods that
-- treat 'Nothing' as loop-back address can be passed here,
-- however 'Nothing' will not be passed by the announcer
-- thread.
--
-- There are two cases:
--
-- [Left] The action to perform requires a search result.
-- This was implemented to support Tox's DHTKey and
-- Friend-Request messages.
--
-- [Right] The action requires a "token" from the destination
-- node. This is the more typical "announce" semantics for
-- Kademlia.
, aBuckets :: TVar (R.BucketList ni)
-- ^ Set this to the current Kademlia routing table buckets.
-- TODO: List of TVars to have separate routing tables for IPv6 and IPv4?
, aTarget :: nid
-- ^ This is the Kademlia node-id of the item being announced.
, aInterval :: POSIXTime
-- ^ Assuming we have nearby nodes from the search, the item
-- will be announced at this interval.
--
-- Current implementation is to make the scheduled
-- announcements even if the search hasn't finished. It will
-- use the closest nodes found so far.
}
-- announcement started:
newAnnouncement :: STM (IO a)
-> IO ()
-> IO ()
-> POSIXTime
-> Announcer
-> AnnounceKey
-> POSIXTime
-> STM (IO ())
newAnnouncement checkFin search announce interval = \announcer k now -> do
modifyTVar (scheduled announcer)
(PSQ.insert' k (ScheduledItem $ reAnnounce checkFin announce interval) (now + interval))
return $ void $ fork search
-- time for periodic announce:
-- (re-)announce to the current known set of storing-nodes.
-- TODO: If the search is finished, restart the search.
reAnnounce :: STM (IO a)
-> IO ()
-> POSIXTime
-> Announcer
-> AnnounceKey
-> POSIXTime
-> STM (IO ())
reAnnounce checkFin announce interval = \announcer k now -> do
isfin <- checkFin
modifyTVar (scheduled announcer)
(PSQ.insert' k (ScheduledItem $ reAnnounce checkFin announce interval) (now + interval))
return $ do
isfin
hPutStrLn stderr $ "This print avoids negative-time future scheduling. Weird bug. TODO: fix it. "++show now
announce
-- | Schedule a recurring Search + Announce sequence.
schedule :: Announcer -> AnnounceKey -> AnnounceMethod r -> r -> IO ()
schedule announcer k AnnounceMethod{aSearch,aPublish,aBuckets,aTarget,aInterval} r = do
st <- atomically $ newSearch aSearch aTarget []
ns <- atomically $ newTVar MM.empty
let astate = AnnounceState st ns
publishToNodes is
| Left _ <- aPublish = return ()
| Right publish <- aPublish = do
forM_ is $ \(Binding ni mtok _) -> do
forM_ mtok $ \tok -> do
got <- publish r tok (Just ni)
now <- getPOSIXTime
forM_ got $ \_ -> do
atomically $ modifyTVar ns $ MM.insertTake announceK ni (Down now)
announce = do -- publish to current search results
is <- atomically $ do
bs <- readTVar (searchInformant st {- :: TVar (MinMaxPSQ' ni nid tok -})
return $ MM.toList bs
publishToNodes is
onResult sr
| Right _ <- aPublish = return True
| Left sendit <- aPublish = do
scheduleImmediately announcer k $ ScheduledItem $ \_ _ _ -> return $ do
got <- sendit r sr
-- If we had a way to get the source of a search result, we might want to
-- treat it similarly to an announcing node and remember it in the 'aStoringNodes'
-- MinMaxPSQ. For now, I'm just letting the nodes for which we've already sent
-- a message be forgotten.
--
-- forM_ got $ \_ -> do
-- atomically $ modifyTVar ns $ MM.insertTake announceK ni (Down now)
return ()
return True -- True to keep searching.
searchAgain = do
-- Canceling a pending search here seems to make announcements more reliable.
searchCancel st
isfin <- searchIsFinished st -- Always True, since we canceled.
return $ when isfin $ void $ fork search
search = do -- thread to fork
atomically $ reset aBuckets aSearch aTarget st
searchLoop aSearch aTarget onResult st
fork $ do -- Announce to any nodes we haven't already announced to.
is <- atomically $ do
bs <- readTVar (searchInformant st {- :: TVar (MinMaxPSQ' ni nid tok -})
nq <- readTVar ns
return $ filter (\(Binding ni _ _) -> not $ isJust $ MM.lookup' ni nq)
$ MM.toList bs
publishToNodes is
return ()
{-
atomically $ scheduleImmediately announcer k
$ SearchFinished {- st -} search announce aInterval
interruptDelay (interrutible announcer)
-}
atomically $ scheduleImmediately announcer k $ ScheduledItem (newAnnouncement searchAgain search announce aInterval)
interruptDelay (interrutible announcer)
|
