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.hs

@@ -75,8 +75,8 @@ startDaemon foreground
 				-- begin adding files and having them
 				-- committed, even while the startup scan
 				-- is taking place.
-				_ <- forkIO $ commitThread st changechan
 				_ <- forkIO $ daemonStatusThread st dstatus
+				_ <- forkIO $ commitThread st dstatus changechan
 				_ <- forkIO $ sanityCheckerThread st dstatus changechan
 				-- Does not return.
 				watchThread st dstatus changechan

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
+				if DirWatcher.closingTracked
+					then do
 						warning $ keyFilename keysource
 							++ " still has writers, not adding"
-				-- remove the hard link
-				--_ <- liftIO $ tryIO $
-				--	removeFile $ contentLocation keysource
+						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. -}

Backend.hs

@@ -6,7 +6,6 @@
  -}
 
 module Backend (
-	B.KeySource(..),
 	list,
 	orderedList,
 	genKey,
@@ -23,6 +22,7 @@ import Config
 import qualified Annex
 import Annex.CheckAttr
 import Types.Key
+import Types.KeySource
 import qualified Types.Backend as B
 
 -- When adding a new backend, import it here and add it to the list.
@@ -54,12 +54,12 @@ orderedList = do
 {- Generates a key for a file, trying each backend in turn until one
  - accepts it.
  -}
-genKey :: B.KeySource -> Maybe Backend -> Annex (Maybe (Key, Backend))
+genKey :: KeySource -> Maybe Backend -> Annex (Maybe (Key, Backend))
 genKey source trybackend = do
 	bs <- orderedList
 	let bs' = maybe bs (: bs) trybackend
 	genKey' bs' source
-genKey' :: [Backend] -> B.KeySource -> Annex (Maybe (Key, Backend))
+genKey' :: [Backend] -> KeySource -> Annex (Maybe (Key, Backend))
 genKey' [] _ = return Nothing
 genKey' (b:bs) source = do
 	r <- B.getKey b source

Backend/SHA.hs

@@ -11,6 +11,7 @@ import Common.Annex
 import qualified Annex
 import Types.Backend
 import Types.Key
+import Types.KeySource
 import qualified Build.SysConfig as SysConfig
 
 type SHASize = Int

Backend/WORM.hs

@@ -10,6 +10,7 @@ module Backend.WORM (backends) where
 import Common.Annex
 import Types.Backend
 import Types.Key
+import Types.KeySource
 
 backends :: [Backend]
 backends = [backend]

Command/Add.hs

@@ -12,6 +12,7 @@ import Annex.Exception
 import Command
 import qualified Annex
 import qualified Annex.Queue
+import Types.KeySource
 import Backend
 import Logs.Location
 import Annex.Content

Command/AddUrl.hs

@@ -20,6 +20,7 @@ import Annex.Content
 import Logs.Web
 import qualified Option
 import Types.Key
+import Types.KeySource
 import Config
 
 def :: [Command]

Command/Migrate.hs

@@ -11,6 +11,7 @@ import Common.Annex
 import Command
 import Backend
 import qualified Types.Key
+import Types.KeySource
 import Annex.Content
 import qualified Command.ReKey
 

Types/Backend.hs

@@ -10,13 +10,7 @@
 module Types.Backend where
 
 import Types.Key
-
-{- The source used to generate a key. The location of the content
- - may be different from the filename associated with the key. -}
-data KeySource = KeySource
-	{ keyFilename :: FilePath
-	, contentLocation :: FilePath
-	}
+import Types.KeySource
 
 data BackendA a = Backend
 	{ name :: String

Types/KeySource.hs

@@ -0,0 +1,33 @@
+{- KeySource data type
+ -
+ - Copyright 2012 Joey Hess <joey@kitenet.net>
+ -
+ - Licensed under the GNU GPL version 3 or higher.
+ -}
+
+module Types.KeySource where
+
+import Data.Ord
+
+{- When content is in the process of being added to the annex,
+ - and a Key generated from it, this data type is used. 
+ -
+ - The contentLocation may be different from the filename
+ - associated with the key. For example, the add command
+ - temporarily puts the content into a lockdown directory
+ - for checking. The migrate command uses the content
+ - of a different Key. -}
+data KeySource = KeySource
+	{ keyFilename :: FilePath
+	, contentLocation :: FilePath
+	}
+	deriving (Show)
+
+{- KeySources are assumed to be equal when the same filename is associated
+ - with the key. The contentLocation can be a random temp file.
+ -}
+instance Eq KeySource where
+	x == y = keyFilename x == keyFilename y
+
+instance Ord KeySource where
+	compare = comparing keyFilename