Merge branch 'watch'

24 files changed, 755 insertions, 205 deletions

diff --git a/.gitignore b/.gitignore
index d628f23b7..afb5f314e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -11,7 +11,7 @@ html
 *.tix
 .hpc
 Utility/Touch.hs
-Utility/libdiskfree.o
+Utility/*.o
 dist
 # Sandboxed builds
 cabal-dev
diff --git a/Assistant.hs b/Assistant.hs
index 880d3eb5e..e924d9477 100644
--- a/Assistant.hs
+++ b/Assistant.hs
@@ -46,6 +46,7 @@ module Assistant where
 import Common.Annex
 import Assistant.ThreadedMonad
 import Assistant.DaemonStatus
+import Assistant.Changes
 import Assistant.Watcher
 import Assistant.Committer
 import Assistant.SanityChecker
diff --git a/Assistant/Changes.hs b/Assistant/Changes.hs
new file mode 100644
index 000000000..173ba1922
--- /dev/null
+++ b/Assistant/Changes.hs
@@ -0,0 +1,81 @@
+{- git-annex assistant change tracking
+ -
+ - Copyright 2012 Joey Hess <joey@kitenet.net>
+ -}
+
+module Assistant.Changes where
+
+import Common.Annex
+import qualified Annex.Queue
+import Types.KeySource
+
+import Control.Concurrent.STM
+import Data.Time.Clock
+
+data ChangeType = AddChange | LinkChange | RmChange | RmDirChange
+	deriving (Show, Eq)
+
+type ChangeChan = TChan Change
+
+data Change
+	= Change 
+		{ changeTime :: UTCTime
+		, changeFile :: FilePath
+		, changeType :: ChangeType
+		}
+	| PendingAddChange
+		{ changeTime ::UTCTime
+		, keySource :: KeySource
+		}
+	deriving (Show)
+
+runChangeChan :: STM a -> IO a
+runChangeChan = atomically
+
+newChangeChan :: IO ChangeChan
+newChangeChan = atomically newTChan
+
+{- Handlers call this when they made a change that needs to get committed. -}
+madeChange :: FilePath -> ChangeType -> Annex (Maybe Change)
+madeChange f t = do
+	-- Just in case the commit thread is not flushing the queue fast enough.
+	Annex.Queue.flushWhenFull
+	liftIO $ Just <$> (Change <$> getCurrentTime <*> pure f <*> pure t)
+
+noChange :: Annex (Maybe Change)
+noChange = return Nothing
+
+{- Indicates an add is in progress. -}
+pendingAddChange :: KeySource -> Annex (Maybe Change)
+pendingAddChange ks =
+	liftIO $ Just <$> (PendingAddChange <$> getCurrentTime <*> pure ks)
+
+isPendingAddChange :: Change -> Bool
+isPendingAddChange (PendingAddChange {}) = True
+isPendingAddChange _ = False
+
+finishedChange :: Change -> Change
+finishedChange c@(PendingAddChange { keySource = ks }) = Change
+	{ changeTime = changeTime c
+	, changeFile = keyFilename ks
+	, changeType = AddChange
+	}
+finishedChange c = c
+
+{- Gets all unhandled changes.
+ - Blocks until at least one change is made. -}
+getChanges :: ChangeChan -> IO [Change]
+getChanges chan = runChangeChan $ do
+	c <- readTChan chan
+	go [c]
+	where
+		go l = do
+			v <- tryReadTChan chan
+			case v of
+				Nothing -> return l
+				Just c -> go (c:l)
+
+{- Puts unhandled changes back into the channel.
+ - Note: Original order is not preserved. -}
+refillChanges :: ChangeChan -> [Change] -> IO ()
+refillChanges chan cs = runChangeChan $ mapM_ (writeTChan chan) cs
diff --git a/Assistant/Committer.hs b/Assistant/Committer.hs
index a2b65dae5..63df8cafc 100644
--- a/Assistant/Committer.hs
+++ b/Assistant/Committer.hs
@@ -1,4 +1,4 @@
-{- git-annex assistant change tracking and committing
+{- git-annex assistant commit thread
  -
  - Copyright 2012 Joey Hess <joey@kitenet.net>
  -}
@@ -6,79 +6,42 @@
 module Assistant.Committer where
 
 import Common.Annex
+import Assistant.Changes
 import Assistant.ThreadedMonad
+import Assistant.Watcher
+import qualified Annex
 import qualified Annex.Queue
 import qualified Git.Command
+import qualified Git.HashObject
+import Git.Types
 import qualified Command.Add
 import Utility.ThreadScheduler
 import qualified Utility.Lsof as Lsof
-import Types.Backend
+import qualified Utility.DirWatcher as DirWatcher
+import Types.KeySource
 
-import Control.Concurrent.STM
 import Data.Time.Clock
 import Data.Tuple.Utils
 import qualified Data.Set as S
-
-data ChangeType = PendingAddChange | LinkChange | RmChange | RmDirChange
-	deriving (Show, Eq)
-
-type ChangeChan = TChan Change
-
-data Change = Change
-	{ changeTime :: UTCTime
-	, changeFile :: FilePath
-	, changeType :: ChangeType
-	}
-	deriving (Show)
-
-runChangeChan :: STM a -> IO a
-runChangeChan = atomically
-
-newChangeChan :: IO ChangeChan
-newChangeChan = atomically newTChan
-
-{- Handlers call this when they made a change that needs to get committed. -}
-madeChange :: FilePath -> ChangeType -> Annex (Maybe Change)
-madeChange f t = do
-	-- Just in case the commit thread is not flushing the queue fast enough.
-	when (t /= PendingAddChange) $
-		Annex.Queue.flushWhenFull
-	liftIO $ Just <$> (Change <$> getCurrentTime <*> pure f <*> pure t)
-
-noChange :: Annex (Maybe Change)
-noChange = return Nothing
-
-{- Gets all unhandled changes.
- - Blocks until at least one change is made. -}
-getChanges :: ChangeChan -> IO [Change]
-getChanges chan = runChangeChan $ do
-	c <- readTChan chan
-	go [c]
-	where
-		go l = do
-			v <- tryReadTChan chan
-			case v of
-				Nothing -> return l
-				Just c -> go (c:l)
-
-{- Puts unhandled changes back into the channel.
- - Note: Original order is not preserved. -}
-refillChanges :: ChangeChan -> [Change] -> IO ()
-refillChanges chan cs = runChangeChan $ mapM_ (writeTChan chan) cs
+import Data.Either
 
 {- This thread makes git commits at appropriate times. -}
 commitThread :: ThreadState -> ChangeChan -> IO ()
 commitThread st 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
+	-- Next, wait until at least one change is available for
+	-- processing.
+	changes <- getChanges changechan
 	-- Now see if now's a good time to commit.
 	time <- getCurrentTime
-	if shouldCommit time cs
+	if shouldCommit time changes
 		then do
-			handleAdds st changechan cs
-			void $ tryIO $ runThreadState st commitStaged
-		else refillChanges changechan cs
+			readychanges <- handleAdds st changechan changes
+			if shouldCommit time readychanges
+				then do
+					void $ tryIO $ runThreadState st commitStaged
+				else refillChanges changechan readychanges
+		else refillChanges changechan changes
 
 commitStaged :: Annex ()
 commitStaged = do
@@ -121,70 +84,112 @@ 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.
+ - staged before returning, and will be committed immediately.
+ -
+ - OTOH, for kqueue, eventsCoalesce, so instead the symlink is directly
+ - created and staged.
+ -
+ - Returns a list of all changes that are ready to be committed.
+ - Any pending adds that are not ready yet are put back into the ChangeChan,
+ - where they will be retried later.
  -}
-handleAdds :: ThreadState -> ChangeChan -> [Change] -> IO ()
-handleAdds st changechan cs
-	| null toadd = noop
-	| otherwise = do
-		toadd' <- safeToAdd st toadd
-		unless (null toadd') $ do
-			added <- filter id <$> forM toadd' add
-			unless (null added) $
-				handleAdds st changechan =<< getChanges changechan
+handleAdds :: ThreadState -> ChangeChan -> [Change] -> IO [Change]
+handleAdds st changechan cs = returnWhen (null pendingadds) $ do
+	(postponed, toadd) <- partitionEithers <$>
+		safeToAdd st pendingadds
+
+	unless (null postponed) $
+		refillChanges changechan postponed
+
+	returnWhen (null toadd) $ do
+		added <- catMaybes <$> forM toadd add
+		if (DirWatcher.eventsCoalesce || null added)
+			then return $ added ++ otherchanges
+			else do
+				r <- handleAdds st changechan
+					=<< getChanges changechan
+				return $ r ++ added ++ otherchanges
 	where
-		toadd = map changeFile $ filter isPendingAdd cs
+		(pendingadds, otherchanges) = partition isPendingAddChange cs
 
-		isPendingAdd (Change { changeType = PendingAddChange }) = True
-		isPendingAdd _ = False
+		returnWhen c a
+			| c = return otherchanges
+			| otherwise = a
 
-		add keysource = catchBoolIO $ runThreadState st $ do
-			showStart "add" $ keyFilename keysource
-			handle (keyFilename keysource)
-				=<< Command.Add.ingest keysource
+		add :: Change -> IO (Maybe Change)
+		add change@(PendingAddChange { keySource = ks }) = do
+			r <- catchMaybeIO $ sanitycheck ks $ runThreadState st $ do
+				showStart "add" $ keyFilename ks
+				handle (finishedChange change) (keyFilename ks)
+					=<< Command.Add.ingest ks
+			return $ maybeMaybe r
+		add _ = return Nothing
 
-		handle _ Nothing = do
+		maybeMaybe (Just j@(Just _)) = j
+		maybeMaybe _ = Nothing
+
+		handle _ _ Nothing = do
 			showEndFail
-			return False
-		handle file (Just key) = do
-			Command.Add.link file key True
+			return Nothing
+		handle change file (Just key) = do
+			link <- Command.Add.link file key True
+			when DirWatcher.eventsCoalesce $ do
+				sha <- inRepo $
+					Git.HashObject.hashObject BlobObject link
+				stageSymlink file sha
 			showEndOk
-			return True
-
-{- Checks which of a set of files can safely be added.
- - Files are locked down as hard links in a temp directory,
- - with their write bits disabled. But some may have already
- - been opened for write, so lsof is run on the temp directory
- - to check them.
+			return $ Just change
+
+		{- Check that the keysource's keyFilename still exists,
+		 - and is still a hard link to its contentLocation,
+		 - before ingesting it. -}
+		sanitycheck keysource a = do
+			fs <- getSymbolicLinkStatus $ keyFilename keysource
+			ks <- getSymbolicLinkStatus $ contentLocation keysource
+			if deviceID ks == deviceID fs && fileID ks == fileID fs
+				then a
+				else return Nothing
+
+{- PendingAddChanges can Either be Right to be added now,
+ - or are unsafe, and must be Left for later.
+ -
+ - Check by running lsof on the temp directory, which
+ - the KeySources are locked down in.
  -}
-safeToAdd :: ThreadState -> [FilePath] -> IO [KeySource]
-safeToAdd st files = do
-	locked <- catMaybes <$> lockdown files
-	runThreadState st $ do
-		tmpdir <- fromRepo gitAnnexTmpDir
-		open <- S.fromList . map fst3 . filter openwrite <$>
-			liftIO (Lsof.queryDir tmpdir)
-		catMaybes <$> forM locked (go open)
+safeToAdd :: ThreadState -> [Change] -> IO [Either Change Change]
+safeToAdd st changes = runThreadState st $
+	ifM (Annex.getState Annex.force)
+		( allRight changes -- force bypasses lsof check
+		, do
+			tmpdir <- fromRepo gitAnnexTmpDir
+			openfiles <- S.fromList . map fst3 . filter openwrite <$>
+				liftIO (Lsof.queryDir tmpdir)
+			
+			let checked = map (check openfiles) changes
+
+			{- If new events are received when files are closed,
+			 - there's no need to retry any changes that cannot
+			 - be done now. -}
+			if DirWatcher.closingTracked
+				then do
+					mapM_ canceladd $ lefts checked
+					allRight $ rights checked
+				else return checked
+		)
 	where
-		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
-				return Nothing
-			| otherwise = return $ Just keysource
-
-		lockdown = mapM $ \file -> do
-			ms <- catchMaybeIO $ getSymbolicLinkStatus file
-			case ms of
-				Just s
-					| isRegularFile s -> 
-						catchMaybeIO $ runThreadState st $
-							Command.Add.lockDown file
-				_ -> return Nothing
-	
+		check openfiles change@(PendingAddChange { keySource = ks })
+			| S.member (contentLocation ks) openfiles = Left change
+		check _ change = Right change
+
+		canceladd (PendingAddChange { keySource = ks }) = do
+			warning $ keyFilename ks
+				++ " still has writers, not adding"
+			-- remove the hard link
+			void $ liftIO $ tryIO $
+				removeFile $ contentLocation ks
+		canceladd _ = noop
 
 		openwrite (_file, mode, _pid) =
 			mode == Lsof.OpenWriteOnly || mode == Lsof.OpenReadWrite
+
+		allRight = return . map Right
diff --git a/Assistant/SanityChecker.hs b/Assistant/SanityChecker.hs
index a5f138024..e2ca9da74 100644
--- a/Assistant/SanityChecker.hs
+++ b/Assistant/SanityChecker.hs
@@ -11,7 +11,7 @@ import Common.Annex
 import qualified Git.LsFiles
 import Assistant.DaemonStatus
 import Assistant.ThreadedMonad
-import Assistant.Committer
+import Assistant.Changes
 import Utility.ThreadScheduler
 import qualified Assistant.Watcher
 
diff --git a/Assistant/Watcher.hs b/Assistant/Watcher.hs
index 1d35b5c1e..db58f01e8 100644
--- a/Assistant/Watcher.hs
+++ b/Assistant/Watcher.hs
@@ -12,15 +12,17 @@ module Assistant.Watcher where
 import Common.Annex
 import Assistant.ThreadedMonad
 import Assistant.DaemonStatus
-import Assistant.Committer
-import Utility.ThreadScheduler
+import Assistant.Changes
+import Utility.DirWatcher
+import Utility.Types.DirWatcher
+import qualified Annex
 import qualified Annex.Queue
 import qualified Git.Command
 import qualified Git.UpdateIndex
 import qualified Git.HashObject
 import qualified Git.LsFiles
 import qualified Backend
-import qualified Annex
+import qualified Command.Add
 import Annex.Content
 import Annex.CatFile
 import Git.Types
@@ -29,24 +31,12 @@ import Control.Concurrent.STM
 import Data.Bits.Utils
 import qualified Data.ByteString.Lazy as L
 
-#ifdef WITH_INOTIFY
-import Utility.Inotify
-import System.INotify
-#endif
-
-type Handler = FilePath -> Maybe FileStatus -> DaemonStatusHandle -> Annex (Maybe Change)
-
 checkCanWatch :: Annex ()
-checkCanWatch = do
-#ifdef WITH_INOTIFY
-	unlessM (liftIO (inPath "lsof") <||> Annex.getState Annex.force) $
-		needLsof
-#else
-#if defined linux_HOST_OS
-#warning "Building without inotify support; watch mode will be disabled."
-#endif
-	error "watch mode is not available on this system"
-#endif
+checkCanWatch
+	| canWatch = 
+		unlessM (liftIO (inPath "lsof") <||> Annex.getState Annex.force) $
+			needLsof
+	| otherwise = error "watch mode is not available on this system"
 
 needLsof :: Annex ()
 needLsof = error $ unlines
@@ -57,22 +47,9 @@ needLsof = error $ unlines
 	]
 
 watchThread :: ThreadState -> DaemonStatusHandle -> ChangeChan -> IO ()
-#ifdef WITH_INOTIFY
-watchThread st dstatus changechan = withINotify $ \i -> do
-	runThreadState st $
-		showAction "scanning"
-	-- This does not return until the startup scan is done.
-	-- That can take some time for large trees.
-	watchDir i "." (ignored . takeFileName) hooks
-	runThreadState st $
-		modifyDaemonStatus dstatus $ \s -> s { scanComplete = True }
-	-- Notice any files that were deleted before inotify
-	-- was started.
-	runThreadState st $ do
-		inRepo $ Git.Command.run "add" [Param "--update"]
-		showAction "started"
-	waitForTermination
+watchThread st dstatus changechan = watchDir "." ignored hooks startup
 	where
+		startup = statupScan st dstatus
 		hook a = Just $ runHandler st dstatus changechan a
 		hooks = WatchHooks
 			{ addHook = hook onAdd
@@ -81,15 +58,32 @@ watchThread st dstatus changechan = withINotify $ \i -> do
 			, delDirHook = hook onDelDir
 			, errHook = hook onErr
 			}
-#else
-watchThread = undefined
-#endif
+
+{- Initial scartup scan. The action should return once the scan is complete. -}
+statupScan :: ThreadState -> DaemonStatusHandle -> IO a -> IO a
+statupScan st dstatus scanner = do
+	runThreadState st $
+		showAction "scanning"
+	r <- scanner
+	runThreadState st $
+		modifyDaemonStatus dstatus $ \s -> s { scanComplete = True }
+
+	-- Notice any files that were deleted before watching was started.
+	runThreadState st $ do
+		inRepo $ Git.Command.run "add" [Param "--update"]
+		showAction "started"
+
+	return r
 
 ignored :: FilePath -> Bool
-ignored ".git" = True
-ignored ".gitignore" = True
-ignored ".gitattributes" = True
-ignored _ = False
+ignored = ig . takeFileName
+	where
+	ig ".git" = True
+	ig ".gitignore" = True
+	ig ".gitattributes" = True
+	ig _ = False
+
+type Handler = FilePath -> Maybe FileStatus -> DaemonStatusHandle -> Annex (Maybe Change)
 
 {- Runs an action handler, inside the Annex monad, and if there was a
  - change, adds it to the ChangeChan.
@@ -117,22 +111,27 @@ runHandler st dstatus changechan handler file filestatus = void $ do
  - and only one has just closed it. We want to avoid adding a file to the
  - annex that is open for write, to avoid anything being able to change it.
  -
- - We could run lsof on the file here to check for other writer.
- - But, that's slow. Instead, a Change is returned that indicates this file
- - still needs to be added. The committer will handle bundles of these
- - Changes at once.
+ - We could run lsof on the file here to check for other writers.
+ - But, that's slow, and even if there is currently a writer, we will want
+ - to add the file *eventually*. Instead, the file is locked down as a hard
+ - link in a temp directory, with its write bits disabled, for later
+ - checking with lsof, and a Change is returned containing a KeySource
+ - using that hard link. The committer handles running lsof and finishing
+ - the add.
  -}
 onAdd :: Handler
-onAdd file _filestatus dstatus = do
-	ifM (scanComplete <$> getDaemonStatus dstatus)
-		( go
-		, ifM (null <$> inRepo (Git.LsFiles.notInRepo False [file]))
-			( noChange
-			, go
+onAdd file filestatus dstatus
+	| maybe False isRegularFile filestatus = do
+		ifM (scanComplete <$> getDaemonStatus dstatus)
+			( go
+			, ifM (null <$> inRepo (Git.LsFiles.notInRepo False [file]))
+				( noChange
+				, go
+				)
 			)
-		)
+	| otherwise = noChange
 	where
-		go = madeChange file PendingAddChange
+		go = pendingAddChange =<< Command.Add.lockDown file
 
 {- A symlink might be an arbitrary symlink, which is just added.
  - Or, if it is a git-annex symlink, ensure it points to the content
diff --git a/Backend.hs b/Backend.hs
index bde1aad78..d1dfdef3c 100644
--- a/Backend.hs
+++ b/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
diff --git a/Backend/SHA.hs b/Backend/SHA.hs
index df613bbcd..838a97ab8 100644
--- a/Backend/SHA.hs
+++ b/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
diff --git a/Backend/WORM.hs b/Backend/WORM.hs
index 630000fa2..523203713 100644
--- a/Backend/WORM.hs
+++ b/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]
diff --git a/Command/Add.hs b/Command/Add.hs
index 7a6696063..73edb5eaa 100644
--- a/Command/Add.hs
+++ b/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
@@ -97,8 +98,8 @@ undo file key e = do
 			src <- inRepo $ gitAnnexLocation key
 			liftIO $ moveFile src file
 
-{- Creates the symlink to the annexed content. -}
-link :: FilePath -> Key -> Bool -> Annex ()
+{- Creates the symlink to the annexed content, returns the link target. -}
+link :: FilePath -> Key -> Bool -> Annex String
 link file key hascontent = handle (undo file key) $ do
 	l <- calcGitLink file key
 	liftIO $ createSymbolicLink l file
@@ -112,6 +113,8 @@ link file key hascontent = handle (undo file key) $ do
 			mtime <- modificationTime <$> getFileStatus file
 			touch file (TimeSpec mtime) False
 
+	return l
+
 {- Note: Several other commands call this, and expect it to 
  - create the symlink and add it. -}
 cleanup :: FilePath -> Key -> Bool -> CommandCleanup
diff --git a/Command/AddUrl.hs b/Command/AddUrl.hs
index 369940bdf..bef1d6875 100644
--- a/Command/AddUrl.hs
+++ b/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]
diff --git a/Command/Migrate.hs b/Command/Migrate.hs
index 29e664ce2..c7c0d7af3 100644
--- a/Command/Migrate.hs
+++ b/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
 
diff --git a/Makefile b/Makefile
index 8884b5c64..73fbc4140 100644
--- a/Makefile
+++ b/Makefile
@@ -1,13 +1,22 @@
-OS:=$(shell uname | sed 's/[-_].*//')
+bins=git-annex
+mans=git-annex.1 git-annex-shell.1
+sources=Build/SysConfig.hs Utility/Touch.hs
+all=$(bins) $(mans) docs
 
+OS:=$(shell uname | sed 's/[-_].*//')
 ifeq ($(OS),Linux)
 BASEFLAGS_OPTS+=-DWITH_INOTIFY
+clibs=Utility/libdiskfree.o
+else
+BASEFLAGS_OPTS+=-DWITH_KQUEUE
+clibs=Utility/libdiskfree.o Utility/libkqueue.o
 endif
 
 PREFIX=/usr
 IGNORE=-ignore-package monads-fd -ignore-package monads-tf
 BASEFLAGS=-Wall $(IGNORE) -outputdir tmp -IUtility -DWITH_S3 $(BASEFLAGS_OPTS)
 GHCFLAGS=-O2 $(BASEFLAGS)
+CFLAGS=-Wall
 
 ifdef PROFILE
 GHCFLAGS=-prof -auto-all -rtsopts -caf-all -fforce-recomp $(BASEFLAGS)
@@ -15,13 +24,6 @@ endif
 
 GHCMAKE=ghc $(GHCFLAGS) --make
 
-bins=git-annex
-mans=git-annex.1 git-annex-shell.1
-sources=Build/SysConfig.hs Utility/Touch.hs
-clibs=Utility/libdiskfree.o
-
-all=$(bins) $(mans) docs
-
 # Am I typing :make in vim? Do a fast build.
 ifdef VIM
 all=fast
diff --git a/Types/Backend.hs b/Types/Backend.hs
index 97f7cef90..d79787c27 100644
--- a/Types/Backend.hs
+++ b/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
diff --git a/Types/KeySource.hs b/Types/KeySource.hs
new file mode 100644
index 000000000..9d1fa173f
--- /dev/null
+++ b/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
diff --git a/Utility/DirWatcher.hs b/Utility/DirWatcher.hs
new file mode 100644
index 000000000..11ce7baef
--- /dev/null
+++ b/Utility/DirWatcher.hs
@@ -0,0 +1,90 @@
+{- generic directory watching interface
+ -
+ - Uses either inotify or kqueue to watch a directory (and subdirectories)
+ - for changes, and runs hooks for different sorts of events as they occur.
+ -
+ - Copyright 2012 Joey Hess <joey@kitenet.net>
+ -
+ - Licensed under the GNU GPL version 3 or higher.
+ -}
+
+{-# LANGUAGE CPP #-}
+
+module Utility.DirWatcher where
+
+import Utility.Types.DirWatcher
+
+#if WITH_INOTIFY
+import qualified Utility.INotify as INotify
+import qualified System.INotify as INotify
+import Utility.ThreadScheduler
+#endif
+#if WITH_KQUEUE
+import qualified Utility.Kqueue as Kqueue
+#endif
+
+type Pruner = FilePath -> Bool
+
+canWatch :: Bool
+#if (WITH_INOTIFY || WITH_KQUEUE)
+canWatch = True
+#else
+#if defined linux_HOST_OS
+#warning "Building without inotify support"
+#endif
+canWatch = False
+#endif
+
+/* With inotify, discrete events will be received when making multiple changes
+ * to the same filename. For example, adding it, deleting it, and adding it
+ * again will be three events.
+ * 
+ * OTOH, with kqueue, often only one event is received, indicating the most
+ * recent state of the file.
+ */
+eventsCoalesce :: Bool
+#if WITH_INOTIFY
+eventsCoalesce = False
+#else
+#if WITH_KQUEUE
+eventsCoalesce = True
+#else
+eventsCoalesce = undefined
+#endif
+#endif
+
+/* With inotify, file closing is tracked to some extent, so an add event
+ * will always be received for a file once its writer closes it, and
+ * (typically) not before. This may mean multiple add events for the same file.
+ *
+ * OTOH, with kqueue, add events will often be received while a file is
+ * still being written to, and then no add event will be received once the
+ * writer closes it.
+ */
+closingTracked :: Bool
+#if WITH_INOTIFY
+closingTracked = True
+#else
+#if WITH_KQUEUE
+closingTracked = False
+#else
+closingTracked = undefined
+#endif
+#endif
+
+#if WITH_INOTIFY
+watchDir :: FilePath -> Pruner -> WatchHooks -> (IO () -> IO ()) -> IO ()
+watchDir dir prune hooks runstartup = INotify.withINotify $ \i -> do
+	runstartup $ INotify.watchDir i dir prune hooks
+	waitForTermination -- Let the inotify thread run.
+#else
+#if WITH_KQUEUE
+watchDir :: FilePath -> Pruner -> WatchHooks -> (IO Kqueue.Kqueue -> IO Kqueue.Kqueue) -> IO ()
+watchDir dir ignored hooks runstartup = do
+	kq <- runstartup $ Kqueue.initKqueue dir ignored
+	Kqueue.runHooks kq hooks
+#else
+watchDir :: FilePath -> Pruner -> WatchHooks -> (IO () -> IO ()) -> IO ()
+watchDir = undefined
+#endif
+#endif
diff --git a/Utility/Directory.hs b/Utility/Directory.hs
index 78bb6e701..2f2960a9d 100644
--- a/Utility/Directory.hs
+++ b/Utility/Directory.hs
@@ -34,7 +34,7 @@ dirCruft _ = False
 dirContents :: FilePath -> IO [FilePath]
 dirContents d = map (d </>) . filter (not . dirCruft) <$> getDirectoryContents d
 
-{- Gets contents of directory, and then its subdirectories, recursively,
+{- Gets files in a directory, and then its subdirectories, recursively,
  - and lazily. -}
 dirContentsRecursive :: FilePath -> IO [FilePath]
 dirContentsRecursive topdir = dirContentsRecursive' topdir [""]
diff --git a/Utility/Inotify.hs b/Utility/INotify.hs
index 9ad947f31..bf87f4e71 100644
--- a/Utility/Inotify.hs
+++ b/Utility/INotify.hs
@@ -5,26 +5,17 @@
  - Licensed under the GNU GPL version 3 or higher.
  -}
 
-module Utility.Inotify where
+module Utility.INotify where
 
 import Common hiding (isDirectory)
 import Utility.ThreadLock
+import Utility.Types.DirWatcher
 
 import System.INotify
 import qualified System.Posix.Files as Files
 import System.IO.Error
 import Control.Exception (throw)
 
-type Hook a = Maybe (a -> Maybe FileStatus -> IO ())
-
-data WatchHooks = WatchHooks
-	{ addHook :: Hook FilePath
-	, addSymlinkHook :: Hook FilePath
-	, delHook :: Hook FilePath
-	, delDirHook :: Hook FilePath
-	, errHook :: Hook String -- error message
-	}
-
 {- Watches for changes to files in a directory, and all its subdirectories
  - that are not ignored, using inotify. This function returns after
  - its initial scan is complete, leaving a thread running. Callbacks are
diff --git a/Utility/Kqueue.hs b/Utility/Kqueue.hs
new file mode 100644
index 000000000..7e7e653ec
--- /dev/null
+++ b/Utility/Kqueue.hs
@@ -0,0 +1,248 @@
+{- BSD kqueue file modification notification interface
+ -
+ - Copyright 2012 Joey Hess <joey@kitenet.net>
+ -
+ - Licensed under the GNU GPL version 3 or higher.
+ -}
+
+{-# LANGUAGE ForeignFunctionInterface #-}
+
+module Utility.Kqueue (
+	Kqueue,
+	initKqueue,
+	stopKqueue,
+	waitChange,
+	Change(..),
+	changedFile,
+	isAdd,
+	isDelete,
+	runHooks,
+) where
+
+import Common
+import Utility.Types.DirWatcher
+
+import System.Posix.Types
+import Foreign.C.Types
+import Foreign.C.Error
+import Foreign.Ptr
+import Foreign.Marshal
+import qualified Data.Map as M
+import qualified Data.Set as S
+import qualified System.Posix.Files as Files
+import Control.Concurrent
+
+data Change
+	= Deleted FilePath
+	| Added FilePath
+	deriving (Show)
+
+isAdd :: Change -> Bool
+isAdd (Added _) = True
+isAdd (Deleted _) = False
+
+isDelete :: Change -> Bool
+isDelete = not . isAdd
+
+changedFile :: Change -> FilePath
+changedFile (Added f) = f
+changedFile (Deleted f) = f
+
+data Kqueue = Kqueue 
+	{ kqueueFd :: Fd
+	, kqueueTop :: FilePath
+	, kqueueMap :: DirMap
+	, _kqueuePruner :: Pruner
+	}
+
+type Pruner = FilePath -> Bool
+
+type DirMap = M.Map Fd DirInfo
+
+{- A directory, and its last known contents (with filenames relative to it) -}
+data DirInfo = DirInfo
+	{ dirName :: FilePath
+	, dirCache :: S.Set FilePath
+	}
+	deriving (Show)
+
+getDirInfo :: FilePath -> IO DirInfo
+getDirInfo dir = do
+	contents <- S.fromList . filter (not . dirCruft)
+		<$> getDirectoryContents dir
+	return $ DirInfo dir contents
+
+{- Difference between the dirCaches of two DirInfos. -}
+(//) :: DirInfo -> DirInfo -> [Change]
+oldc // newc = deleted ++ added
+	where
+		deleted = calc Deleted oldc newc
+		added   = calc Added newc oldc
+		calc a x y = map a . map (dirName x </>) $
+			S.toList $ S.difference (dirCache x) (dirCache y)
+
+{- Builds a map of directories in a tree, possibly pruning some.
+ - Opens each directory in the tree, and records its current contents. -}
+scanRecursive :: FilePath -> Pruner -> IO DirMap
+scanRecursive topdir prune = M.fromList <$> walk [] [topdir]
+	where
+		walk c [] = return c
+		walk c (dir:rest)
+			| prune dir = walk c rest
+			| otherwise = do
+				minfo <- catchMaybeIO $ getDirInfo dir
+				case minfo of
+					Nothing -> walk c rest
+					Just info -> do
+						mfd <- catchMaybeIO $
+							openFd dir ReadOnly Nothing defaultFileFlags
+						case mfd of
+							Nothing -> walk c rest
+							Just fd -> do
+								let subdirs = map (dir </>) $
+									S.toList $ dirCache info
+								walk ((fd, info):c) (subdirs ++ rest)
+
+{- Adds a list of subdirectories (and all their children), unless pruned to a
+ - directory map. Adding a subdirectory that's already in the map will
+ - cause its contents to be refreshed. -}
+addSubDirs :: DirMap -> Pruner -> [FilePath] -> IO DirMap
+addSubDirs dirmap prune dirs = do
+	newmap <- foldr M.union M.empty <$>
+		mapM (\d -> scanRecursive d prune) dirs
+	return $ M.union newmap dirmap -- prefer newmap
+
+{- Removes a subdirectory (and all its children) from a directory map. -}
+removeSubDir :: DirMap -> FilePath -> IO DirMap
+removeSubDir dirmap dir = do
+	mapM_ closeFd $ M.keys toremove
+	return rest
+	where
+		(toremove, rest) = M.partition (dirContains dir . dirName) dirmap
+
+findDirContents :: DirMap -> FilePath -> [FilePath]
+findDirContents dirmap dir = concatMap absolutecontents $ search
+	where
+		absolutecontents i = map (dirName i </>) (S.toList $ dirCache i)
+		search = map snd $ M.toList $
+			M.filter (\i -> dirName i == dir) dirmap
+
+foreign import ccall unsafe "libkqueue.h init_kqueue" c_init_kqueue
+	:: IO Fd
+foreign import ccall unsafe "libkqueue.h addfds_kqueue" c_addfds_kqueue
+	:: Fd -> CInt -> Ptr Fd -> IO ()
+foreign import ccall unsafe "libkqueue.h waitchange_kqueue" c_waitchange_kqueue
+	:: Fd -> IO Fd
+
+{- Initializes a Kqueue to watch a directory, and all its subdirectories. -}
+initKqueue :: FilePath -> Pruner -> IO Kqueue
+initKqueue dir pruned = do
+	dirmap <- scanRecursive dir pruned
+	h <- c_init_kqueue
+	let kq = Kqueue h dir dirmap pruned
+	updateKqueue kq
+	return kq
+
+{- Updates a Kqueue, adding watches for its map. -}
+updateKqueue :: Kqueue -> IO ()
+updateKqueue (Kqueue h _ dirmap _) =
+	withArrayLen (M.keys dirmap) $ \fdcnt c_fds -> do
+		c_addfds_kqueue h (fromIntegral fdcnt) c_fds
+
+{- Stops a Kqueue. Note: Does not directly close the Fds in the dirmap,
+ - so it can be reused.  -}
+stopKqueue :: Kqueue -> IO ()
+stopKqueue = closeFd . kqueueFd
+
+{- Waits for a change on a Kqueue.
+ - May update the Kqueue.
+ -}
+waitChange :: Kqueue -> IO (Kqueue, [Change])
+waitChange kq@(Kqueue h _ dirmap _) = do
+	changedfd <- c_waitchange_kqueue h
+	if changedfd == -1
+		then ifM ((==) eINTR <$> getErrno)
+			(yield >> waitChange kq, nochange)
+		else case M.lookup changedfd dirmap of
+			Nothing -> nochange
+			Just info -> handleChange kq changedfd info
+	where
+		nochange = return (kq, [])
+
+{- The kqueue interface does not tell what type of change took place in
+ - the directory; it could be an added file, a deleted file, a renamed
+ - file, a new subdirectory, or a deleted subdirectory, or a moved
+ - subdirectory. 
+ -
+ - So to determine this, the contents of the directory are compared
+ - with its last cached contents. The Kqueue is updated to watch new
+ - directories as necessary.
+ -}
+handleChange :: Kqueue -> Fd -> DirInfo -> IO (Kqueue, [Change])
+handleChange kq@(Kqueue _ _ dirmap pruner) fd olddirinfo =
+	go =<< catchMaybeIO (getDirInfo $ dirName olddirinfo)
+	where
+		go (Just newdirinfo) = do
+			let changes = olddirinfo // newdirinfo
+			let (added, deleted) = partition isAdd changes
+
+			-- Scan newly added directories to add to the map.
+			-- (Newly added files will fail getDirInfo.)
+			newdirinfos <- catMaybes <$>
+				mapM (catchMaybeIO . getDirInfo . changedFile) added
+			newmap <- addSubDirs dirmap pruner $ map dirName newdirinfos
+
+			-- Remove deleted directories from the map.
+			newmap' <- foldM removeSubDir newmap (map changedFile deleted)
+
+			-- Update the cached dirinfo just looked up.
+			let newmap'' = M.insertWith' const fd newdirinfo newmap'
+
+			-- When new directories were added, need to update
+			-- the kqueue to watch them.
+			let kq' = kq { kqueueMap = newmap'' }
+			unless (null newdirinfos) $
+				updateKqueue kq'
+
+			return (kq', changes)
+		go Nothing = do
+			-- The directory has been moved or deleted, so
+			-- remove it from our map.
+			newmap <- removeSubDir dirmap (dirName olddirinfo)
+			return (kq { kqueueMap = newmap }, [])
+
+{- Processes changes on the Kqueue, calling the hooks as appropriate.
+ - Never returns. -}
+runHooks :: Kqueue -> WatchHooks -> IO ()
+runHooks kq hooks = do
+	-- First, synthetic add events for the whole directory tree contents,
+	-- to catch any files created beforehand.
+	recursiveadd (kqueueMap kq) (Added $ kqueueTop kq)
+	loop kq
+	where
+		loop q = do
+			(q', changes) <- waitChange q
+			forM_ changes $ dispatch (kqueueMap q')
+			loop q'
+		-- Kqueue returns changes for both whole directories
+		-- being added and deleted, and individual files being
+		-- added and deleted.
+		dispatch dirmap change
+			| isAdd change = withstatus change $ dispatchadd dirmap
+			| otherwise = callhook delDirHook Nothing change
+		dispatchadd dirmap change s
+			| Files.isSymbolicLink s =
+				callhook addSymlinkHook (Just s) change
+			| Files.isDirectory s = recursiveadd dirmap change
+			| Files.isRegularFile s =
+				callhook addHook (Just s) change
+			| otherwise = noop
+		recursiveadd dirmap change = do
+			let contents = findDirContents dirmap $ changedFile change
+			forM_ contents $ \f ->
+				withstatus (Added f) $ dispatchadd dirmap
+		callhook h s change = case h hooks of
+			Nothing -> noop
+			Just a -> a (changedFile change) s
+		withstatus change a = maybe noop (a change) =<<
+			(catchMaybeIO (getSymbolicLinkStatus (changedFile change)))
diff --git a/Utility/Types/DirWatcher.hs b/Utility/Types/DirWatcher.hs
new file mode 100644
index 000000000..c828a0593
--- /dev/null
+++ b/Utility/Types/DirWatcher.hs
@@ -0,0 +1,22 @@
+{- generic directory watching types
+ -
+ - Copyright 2012 Joey Hess <joey@kitenet.net>
+ -
+ - Licensed under the GNU GPL version 3 or higher.
+ -}
+
+{-# LANGUAGE CPP #-}
+
+module Utility.Types.DirWatcher where
+
+import Common
+
+type Hook a = Maybe (a -> Maybe FileStatus -> IO ())
+
+data WatchHooks = WatchHooks
+	{ addHook :: Hook FilePath
+	, addSymlinkHook :: Hook FilePath
+	, delHook :: Hook FilePath
+	, delDirHook :: Hook FilePath
+	, errHook :: Hook String -- error message
+	}
diff --git a/Utility/libkqueue.c b/Utility/libkqueue.c
new file mode 100644
index 000000000..b5a19a135
--- /dev/null
+++ b/Utility/libkqueue.c
@@ -0,0 +1,73 @@
+/* kqueue interface, C mini-library
+ *
+ * Copyright 2012 Joey Hess <joey@kitenet.net>
+ *
+ * Licensed under the GNU GPL version 3 or higher.
+ */
+
+#include <stdio.h>
+#include <dirent.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/event.h>
+#include <sys/time.h>
+#include <errno.h>
+
+/* The specified fds are added to the set of fds being watched for changes.
+ * Fds passed to prior calls still take effect, so it's most efficient to
+ * not pass the same fds repeatedly.
+ *
+ * Returns the fd that changed, or -1 on error.
+ */
+signed int helper(const int kq, const int fdcnt, const int *fdlist, int nodelay) {
+	int i, nev;
+	struct kevent evlist[1];
+	struct kevent chlist[fdcnt];
+	struct timespec avoiddelay = {0, 0};
+	struct timespec *timeout = nodelay ? &avoiddelay : NULL;
+	
+	for (i = 0; i < fdcnt; i++) {
+		EV_SET(&chlist[i], fdlist[i], EVFILT_VNODE,
+			EV_ADD | EV_ENABLE | EV_CLEAR,
+			NOTE_WRITE,
+			0, 0);
+	}
+
+	nev = kevent(kq, chlist, fdcnt, evlist, 1, timeout);
+	if (nev == 1)
+		return evlist[0].ident;
+	else
+		return -1;
+}
+
+/* Initializes a new, empty kqueue. */
+int init_kqueue() {
+	int kq;
+	if ((kq = kqueue()) == -1) {
+		perror("kqueue");
+		exit(1);
+	}
+	return kq;
+}
+
+/* Adds fds to the set that should be watched. */
+void addfds_kqueue(const int kq, const int fdcnt, const int *fdlist) {
+	helper(kq, fdcnt, fdlist, 1);
+}
+
+/* Waits for a change event on a kqueue. */
+signed int waitchange_kqueue(const int kq) {
+	return helper(kq, 0, NULL, 0);
+}
+
+/*
+main () {
+	int list[1];
+	int kq;
+	list[0]=open(".", O_RDONLY);
+	kq = init_kqueue();
+	addfds_kqueue(kq, 1, list)
+	printf("change: %i\n", waitchange_kqueue(kq));
+}
+*/
diff --git a/Utility/libkqueue.h b/Utility/libkqueue.h
new file mode 100644
index 000000000..692b47f14
--- /dev/null
+++ b/Utility/libkqueue.h
@@ -0,0 +1,3 @@
+int init_kqueue();
+void addfds_kqueue(const int kq, const int fdcnt, const int *fdlist);
+signed int waitchange_kqueue(const int kq);
diff --git a/debian/changelog b/debian/changelog
index bc9932d52..5d8d973c6 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,9 +1,10 @@
 git-annex (3.20120616) UNRELEASED; urgency=low
 
-  * watch: New subcommand, which uses inotify to watch for changes to
-    files and automatically annexes new files, etc, so you don't need
-    to manually run git commands when manipulating files.
-  * Enable diskfree on kfreebsd, using statvfs.
+  * watch: New subcommand, a daemon which notices changes to
+    files and automatically annexes new files, etc, so you don't
+    need to manually run git commands when manipulating files.
+    Available on Linux, BSDs, and OSX!
+  * Enable diskfree on kfreebsd, using kqueue.
   * unused: Fix crash when key names contain invalid utf8.
 
  -- Joey Hess <joeyh@debian.org>  Tue, 12 Jun 2012 11:35:59 -0400
diff --git a/debian/control b/debian/control
index 3b142dc5f..bcecbec3d 100644
--- a/debian/control
+++ b/debian/control
@@ -41,8 +41,8 @@ Depends: ${misc:Depends}, ${shlibs:Depends},
 	uuid,
 	rsync,
 	wget | curl,
-	openssh-client (>= 1:5.6p1),
-	lsof
+	openssh-client (>= 1:5.6p1)
+Recommends: lsof
 Suggests: graphviz, bup, gnupg
 Description: manage files with git, without checking their contents into git
  git-annex allows managing files with git, without checking the file