diff options
author | 2016-12-09 14:52:38 -0400 | |
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committer | 2016-12-09 15:01:09 -0400 | |
commit | b3b800bb6140543306ec65751506ae2862ca345f (patch) | |
tree | 6357ef2d4ea6a6f302b9b00f45d25e4c997b5ec2 /Command | |
parent | 94e91f857e9ae3522c31c3d2268475aeae45fdb3 (diff) |
refactor ref change watching
Added to change notification to P2P protocol.
Switched to a TBChan so that a single long-running thread can be
started, and serve perhaps intermittent requests for change
notifications, without buffering all changes in memory.
The P2P runner currently starts up a new thread each times it waits
for a change, but that should allow later reusing a thread. Although
each connection from a peer will still need a new watcher thread to run.
The dependency on stm-chans is more or less free; some stuff in yesod
uses it, so it was already indirectly pulled in when building with the
webapp.
This commit was sponsored by Francois Marier on Patreon.
Diffstat (limited to 'Command')
-rw-r--r-- | Command/NotifyChanges.hs | 48 |
1 files changed, 6 insertions, 42 deletions
diff --git a/Command/NotifyChanges.hs b/Command/NotifyChanges.hs index bb9b10eee..83d7bca3f 100644 --- a/Command/NotifyChanges.hs +++ b/Command/NotifyChanges.hs @@ -8,6 +8,7 @@ module Command.NotifyChanges where import Command +import Annex.ChangedRefs import Utility.DirWatcher import Utility.DirWatcher.Types import qualified Git @@ -30,55 +31,18 @@ seek = withNothing start start :: CommandStart start = do - -- This channel is used to accumulate notifcations, - -- because the DirWatcher might have multiple threads that find - -- changes at the same time. - chan <- liftIO newTChanIO - - g <- gitRepo - let refdir = Git.localGitDir g </> "refs" - liftIO $ createDirectoryIfMissing True refdir + h <- watchChangedRefs - let notifyhook = Just $ notifyHook chan - let hooks = mkWatchHooks - { addHook = notifyhook - , modifyHook = notifyhook - } - - void $ liftIO $ watchDir refdir (const False) True hooks id - - let sender = do - send READY - forever $ send . CHANGED =<< drain chan - -- 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 -notifyHook :: TChan Git.Sha -> FilePath -> Maybe FileStatus -> IO () -notifyHook chan reffile _ - | ".lock" `isSuffixOf` reffile = noop - | otherwise = void $ do - sha <- catchDefaultIO Nothing $ - extractSha <$> readFile reffile - maybe noop (atomically . writeTChan chan) sha - --- When possible, coalesce ref writes that occur closely together --- in time. Delay up to 0.05 seconds to get more ref writes. -drain :: TChan Git.Sha -> IO [Git.Sha] -drain chan = do - r <- atomically $ readTChan chan - threadDelay 50000 - rs <- atomically $ drain' chan - return (r:rs) - -drain' :: TChan Git.Sha -> STM [Git.Sha] -drain' chan = loop [] - where - loop rs = maybe (return rs) (\r -> loop (r:rs)) =<< tryReadTChan chan - send :: Notification -> IO () send n = do putStrLn $ unwords $ formatMessage n |