git-annex/Command/NotifyChanges.hs
Joey Hess 53526136e8
move commandAction out of CmdLine.Seek
This is groundwork for nested seek loops, eg seeking over all files and
then performing commandActions on a list of remotes, which can be done
concurrently.

This commit was sponsored by Boyd Stephen Smith Jr. on Patreon.
2018-10-01 14:12:06 -04:00

44 lines
1.1 KiB
Haskell

{- git-annex-shell command
-
- Copyright 2014 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Command.NotifyChanges where
import Command
import Annex.ChangedRefs
import RemoteDaemon.Transport.Ssh.Types
import Utility.SimpleProtocol
import Control.Concurrent.Async
cmd :: Command
cmd = noCommit $
command "notifychanges" SectionPlumbing
"sends notification when git refs are changed"
paramNothing (withParams seek)
seek :: CmdParams -> CommandSeek
seek = withNothing (commandAction start)
start :: CommandStart
start = go =<< watchChangedRefs
where
go (Just h) = do
-- No messages need to be received from the caller,
-- but when it closes the connection, notice and terminate.
let receiver = forever $ void $ getProtocolLine stdin
let sender = forever $ send . CHANGED =<< waitChangedRefs h
liftIO $ send READY
void $ liftIO $ concurrently sender receiver
liftIO $ stopWatchingChangedRefs h
stop
go Nothing = stop
send :: Notification -> IO ()
send n = do
putStrLn $ unwords $ formatMessage n
hFlush stdout