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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 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
announceK :: Int
announceK = 8
data AnnounceState = forall nid addr tok ni r qk. AnnounceState
{ aState :: SearchState nid addr tok ni r qk
, 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 qk.
( Show nid
, Hashable nid
, Hashable ni
, Ord addr
, Ord nid
, Ord ni
, Ord qk
) => AnnounceMethod
{ aSearch :: Search nid addr tok ni sr qk
-- ^ 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 :: 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.
--
-- The action requires a "token" from the destination
-- node. This is the more typical "announce" semantics for
-- Kademlia.
, aNearestNodes :: nid -> STM [ni]
-- ^ Method to obtain starting nodes from an iterative Kademlia search.
, 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.
}
-- | This type specifies a Kademlia search and an action to perform upon the result.
data SearchMethod r = forall nid ni sr addr tok a qk.
( Show nid
, Hashable nid
, Hashable ni
, Ord addr
, Ord nid
, Ord ni
, Ord qk
) => SearchMethod
{ sSearch :: Search nid addr tok ni sr qk
-- ^ 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.
--
-- XXX: Currently, "repeatedly" is wrong.
, sWithResult :: r -> sr -> IO ()
-- ^
-- The action to perform upon a search result. This was
-- implemented to support Tox's DHTKey and Friend-Request
-- messages.
, sNearestNodes :: nid -> STM [ni]
-- ^ Method to obtain starting nodes from an iterative Kademlia search.
, sTarget :: nid
-- ^ This is the Kademlia node-id of the item being announced.
, sInterval :: POSIXTime
-- ^ The time between searches.
--
-- XXX: Currently, search results will stop any repetition.
}
-- announcement started:
newAnnouncement :: STM (IO a)
-> IO ()
-> IO ()
-> POSIXTime
-> Announcer
-> AnnounceKey
-> POSIXTime
-> STM (IO ())
newAnnouncement checkFin search announce interval = \announcer k now -> do
scheduleAbs announcer 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
scheduleAbs announcer k (ScheduledItem $ reAnnounce checkFin announce interval) (now + interval)
return $ do
isfin
announce
-- | Schedule a recurring Search + Announce sequence.
scheduleAnnounce :: Announcer -> AnnounceKey -> AnnounceMethod r -> r -> IO ()
scheduleAnnounce announcer k AnnounceMethod{aSearch,aPublish,aNearestNodes,aTarget,aInterval} r = do
st <- atomically $ newSearch aSearch aTarget []
ns <- atomically $ newTVar MM.empty
mutex <- newMVar () -- This mutex insures one search at a time.
let astate = AnnounceState st ns
publishToNodes is = do
forM_ is $ \(Binding ni mtok _) -> do
forM_ mtok $ \tok -> do
got <- aPublish 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 = return True
searchAgain = do
return $ void $ do
t <- fork search
labelThread t ("scheduleAnnounce.sch." ++ show aTarget)
search = do -- thread to fork
got <- tryTakeMVar mutex
case got of
Just () -> do
me <- myThreadId
labelThread me "scheduleAnnounce.reset"
reset aNearestNodes aSearch aTarget st
labelThread me "scheduleAnnounce.searchLoop"
searchLoop aSearch aTarget onResult st
-- 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
putMVar mutex ()
Nothing -> do
-- Previous search did not finish. Instead of starting a new search,
-- we will re-announce only.
announce
-- Cancel search so that a new one can start in the nest period.
atomically $ searchCancel st
atomically $ scheduleImmediately announcer k $ ScheduledItem (newAnnouncement searchAgain search announce aInterval)
-- | Schedule a recurring Search + Publish sequence.
scheduleSearch :: Announcer -> AnnounceKey -> SearchMethod r -> r -> IO ()
scheduleSearch announcer k SearchMethod{sSearch,sWithResult,sNearestNodes,sTarget,sInterval} r = do
st <- atomically $ newSearch sSearch sTarget []
ns <- atomically $ newTVar MM.empty
mutex <- newMVar () -- This mutex insures one search at a time.
let astate = AnnounceState st ns
onResult sr = do
runAction announcer ("search-result:"++unpackAnnounceKey announcer k) $ do
got <- sWithResult 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
return $ void $ do
t <- fork search
labelThread t ("scheduleSearch.sch." ++ show sTarget)
search = do -- thread to fork
got <- tryTakeMVar mutex
case got of
Just () -> do
me <- myThreadId
labelThread me "scheduleSearch.reset"
reset sNearestNodes sSearch sTarget st
labelThread me "scheduleSearch.searchLoop"
searchLoop sSearch sTarget onResult st
putMVar mutex ()
Nothing -> do
-- Cancel search so that a new one can start in the nest period.
atomically $ searchCancel st
atomically $ scheduleImmediately announcer k $ ScheduledItem (newAnnouncement searchAgain search (return ()) sInterval)
|
