git-annex/Remote/Helper/P2P.hs
2020-05-14 14:11:05 -04:00

75 lines
2.5 KiB
Haskell

{- Helpers for remotes using the git-annex P2P protocol.
-
- Copyright 2016-2020 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
{-# LANGUAGE RankNTypes #-}
module Remote.Helper.P2P where
import Annex.Common
import qualified P2P.Protocol as P2P
import P2P.IO
import Types.Remote
import Annex.Content
import Messages.Progress
import Utility.Metered
import Types.NumCopies
import Control.Concurrent
-- Runs a Proto action using a connection it sets up.
type ProtoRunner a = P2P.Proto a -> Annex (Maybe a)
-- Runs a Proto action using a ClosableConnection.
type ProtoConnRunner c = forall a. P2P.Proto a -> ClosableConnection c -> Annex (ClosableConnection c, Maybe a)
-- Runs an Annex action with a connection from the pool, adding it back to
-- the pool when done.
type WithConn a c = (ClosableConnection c -> Annex (ClosableConnection c, a)) -> Annex a
store :: (MeterUpdate -> ProtoRunner Bool) -> Key -> AssociatedFile -> MeterUpdate -> Annex ()
store runner k af p = do
let sizer = KeySizer k (fmap fst <$> prepSendAnnex k)
metered (Just p) sizer $ \_ p' ->
runner p' (P2P.put k af p') >>= \case
Just True -> return ()
Just False -> giveup "transfer failed"
Nothing -> remoteUnavail
retrieve :: (MeterUpdate -> ProtoRunner (Bool, Verification)) -> Key -> AssociatedFile -> FilePath -> MeterUpdate -> Annex Verification
retrieve runner k af dest p =
metered (Just p) k $ \m p' ->
runner p' (P2P.get dest k af m p') >>= \case
Just (True, v) -> return v
Just (False, _) -> giveup "transfer failed"
Nothing -> remoteUnavail
remove :: ProtoRunner Bool -> Key -> Annex ()
remove runner k = runner (P2P.remove k) >>= \case
Just True -> return ()
Just False -> giveup "removing content from remote failed"
Nothing -> remoteUnavail
checkpresent :: ProtoRunner Bool -> Key -> Annex Bool
checkpresent runner k = maybe remoteUnavail return =<< runner (P2P.checkPresent k)
lock :: WithConn a c -> ProtoConnRunner c -> UUID -> Key -> (VerifiedCopy -> Annex a) -> Annex a
lock withconn connrunner u k callback = withconn $ \conn -> do
connv <- liftIO $ newMVar conn
let runproto d p = do
c <- liftIO $ takeMVar connv
(c', mr) <- connrunner p c
liftIO $ putMVar connv c'
return (fromMaybe d mr)
r <- P2P.lockContentWhile runproto k go
conn' <- liftIO $ takeMVar connv
return (conn', r)
where
go False = giveup "can't lock content"
go True = withVerifiedCopy LockedCopy u (return True) callback
remoteUnavail :: a
remoteUnavail = giveup "can't connect to remote"