maintain set of files pendingAdd

Kqueue needs to remember which files failed to be added due to being open,
and retry them. This commit gets the data in place for such a retry thread.

Broke KeySource out into its own file, and added Eq and Ord instances
so it can be stored in a Set.

Assistant/Committer.hs

@@ -7,6 +7,7 @@ module Assistant.Committer where
 
 import Common.Annex
 import Assistant.Changes
+import Assistant.DaemonStatus
 import Assistant.ThreadedMonad
 import Assistant.Watcher
 import qualified Annex
@@ -18,15 +19,15 @@ import qualified Command.Add
 import Utility.ThreadScheduler
 import qualified Utility.Lsof as Lsof
 import qualified Utility.DirWatcher as DirWatcher
-import Types.Backend
+import Types.KeySource
 
 import Data.Time.Clock
 import Data.Tuple.Utils
 import qualified Data.Set as S
 
 {- This thread makes git commits at appropriate times. -}
-commitThread :: ThreadState -> ChangeChan -> IO ()
-commitThread st changechan = runEvery (Seconds 1) $ do
+commitThread :: ThreadState -> DaemonStatusHandle -> ChangeChan -> IO ()
+commitThread st dstatus changechan = runEvery (Seconds 1) $ do
 	-- We already waited one second as a simple rate limiter.
 	-- Next, wait until at least one change has been made.
 	cs <- getChanges changechan
@@ -34,7 +35,7 @@ commitThread st changechan = runEvery (Seconds 1) $ do
 	time <- getCurrentTime
 	if shouldCommit time cs
 		then do
-			handleAdds st changechan cs
+			handleAdds st dstatus changechan cs
 			void $ tryIO $ runThreadState st commitStaged
 		else refillChanges changechan cs
 
@@ -79,19 +80,20 @@ shouldCommit now changes
  -
  - When a file is added, Inotify will notice the new symlink. So this waits
  - for additional Changes to arrive, so that the symlink has hopefully been
- - staged before returning, and will be committed immediately. OTOH, for
- - kqueue, eventsCoalesce, so instead the symlink is directly created and
- - staged.
+ - staged before returning, and will be committed immediately.
+ -
+ - OTOH, for kqueue, eventsCoalesce, so instead the symlink is directly
+ - created and staged, if the file is not open.
  -}
-handleAdds :: ThreadState -> ChangeChan -> [Change] -> IO ()
-handleAdds st changechan cs
+handleAdds :: ThreadState -> DaemonStatusHandle -> ChangeChan -> [Change] -> IO ()
+handleAdds st dstatus changechan cs
 	| null toadd = noop
 	| otherwise = do
-		toadd' <- safeToAdd st toadd
+		toadd' <- safeToAdd st dstatus toadd
 		unless (null toadd') $ do
 			added <- filter id <$> forM toadd' add
 			unless (DirWatcher.eventsCoalesce || null added) $
-				handleAdds st changechan
+				handleAdds st dstatus changechan
 					=<< getChanges changechan
 	where
 		toadd = map changeFile $ filter isPendingAdd cs
@@ -122,8 +124,8 @@ handleAdds st changechan cs
  - opened for write, so lsof is run on the temp directory
  - to check them.
  -}
-safeToAdd :: ThreadState -> [FilePath] -> IO [KeySource]
-safeToAdd st files = do
+safeToAdd :: ThreadState -> DaemonStatusHandle -> [FilePath] -> IO [KeySource]
+safeToAdd st dstatus files = do
 	locked <- catMaybes <$> lockdown files
 	runThreadState st $ ifM (Annex.getState Annex.force)
 		( return locked -- force bypasses lsof check
@@ -134,16 +136,33 @@ safeToAdd st files = do
 			catMaybes <$> forM locked (go open)
 		)
 	where
+ 		{- When a file is still open, it can be put into pendingAdd
+		 - to be checked again later. However when closingTracked
+		 - is supported, another event will be received once it's
+		 - closed, so there's no point in doing so. -}
 		go open keysource
 			| S.member (contentLocation keysource) open = do
-				warning $ keyFilename keysource
-					++ " still has writers, not adding"
-				-- remove the hard link
-				--_ <- liftIO $ tryIO $
-				--	removeFile $ contentLocation keysource
+				if DirWatcher.closingTracked
+					then do
+						warning $ keyFilename keysource
+							++ " still has writers, not adding"
+						void $ liftIO $ canceladd keysource
+					else void $ addpending keysource
 				return Nothing
 			| otherwise = return $ Just keysource
 
+		canceladd keysource = tryIO $
+			-- remove the hard link
+			removeFile $ contentLocation keysource
+
+		{- The same file (or a file with the same name)
+		 - could already be pending add; if so this KeySource
+		 - superscedes the old one. -}
+		addpending keysource = modifyDaemonStatusM dstatus $ \s -> do
+			let set = pendingAdd s
+			mapM_ canceladd $ S.toList $ S.filter (== keysource) set
+			return $ s { pendingAdd = S.insert keysource set }
+
 		lockdown = mapM $ \file -> do
 			ms <- catchMaybeIO $ getSymbolicLinkStatus file
 			case ms of

Assistant/DaemonStatus.hs

@@ -9,12 +9,14 @@ import Common.Annex
 import Assistant.ThreadedMonad
 import Utility.ThreadScheduler
 import Utility.TempFile
+import Types.KeySource
 
 import Control.Concurrent
 import System.Posix.Types
 import Data.Time.Clock.POSIX
 import Data.Time
 import System.Locale
+import qualified Data.Set as S
 
 data DaemonStatus = DaemonStatus
 	-- False when the daemon is performing its startup scan
@@ -25,6 +27,8 @@ data DaemonStatus = DaemonStatus
 	, sanityCheckRunning :: Bool
 	-- Last time the sanity checker ran
 	, lastSanityCheck :: Maybe POSIXTime
+	-- Files that are in the process of being added to the annex.
+	, pendingAdd :: S.Set KeySource
 	}
 	deriving (Show)
 
@@ -36,13 +40,17 @@ newDaemonStatus = DaemonStatus
 	, lastRunning = Nothing
 	, sanityCheckRunning = False
 	, lastSanityCheck = Nothing
+	, pendingAdd = S.empty
 	}
 
 getDaemonStatus :: DaemonStatusHandle -> Annex DaemonStatus
 getDaemonStatus = liftIO . readMVar
 
 modifyDaemonStatus :: DaemonStatusHandle -> (DaemonStatus -> DaemonStatus) -> Annex ()
-modifyDaemonStatus handle a = liftIO $ modifyMVar_ handle (return . a)
+modifyDaemonStatus handle a = modifyDaemonStatusM handle (return . a)
+
+modifyDaemonStatusM :: DaemonStatusHandle -> (DaemonStatus -> IO DaemonStatus) -> Annex ()
+modifyDaemonStatusM handle a = liftIO $ modifyMVar_ handle a
 
 {- Load any previous daemon status file, and store it in the MVar for this
  - process to use as its DaemonStatus. -}