f340fd324c
This gets directory renames closer to being fully detected. There's close to no extra overhead to doing it this way.
281 lines
8.2 KiB
Haskell
281 lines
8.2 KiB
Haskell
{- git-annex assistant tree watcher
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-
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- Copyright 2012 Joey Hess <joey@kitenet.net>
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-
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- Licensed under the GNU GPL version 3 or higher.
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-}
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{-# LANGUAGE DeriveDataTypeable, CPP #-}
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module Assistant.Threads.Watcher (
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watchThread,
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WatcherException(..),
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checkCanWatch,
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needLsof,
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onAddSymlink,
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runHandler,
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) where
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import Assistant.Common
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import Assistant.DaemonStatus
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import Assistant.Changes
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import Assistant.Types.Changes
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import Assistant.Alert
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import Utility.DirWatcher
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import Utility.DirWatcher.Types
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import Utility.Lsof
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import qualified Annex
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import qualified Annex.Queue
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import qualified Git
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import qualified Git.UpdateIndex
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import qualified Git.LsFiles as LsFiles
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import qualified Backend
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import Annex.Content
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import Annex.Direct
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import Annex.Content.Direct
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import Annex.CatFile
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import Annex.Link
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import Git.Types
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import Config
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import Utility.ThreadScheduler
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import Data.Bits.Utils
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import Data.Typeable
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import qualified Data.ByteString.Lazy as L
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import qualified Control.Exception as E
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import Data.Time.Clock
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checkCanWatch :: Annex ()
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checkCanWatch
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| canWatch = do
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liftIO setupLsof
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unlessM (liftIO (inPath "lsof") <||> Annex.getState Annex.force)
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needLsof
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| otherwise = error "watch mode is not available on this system"
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needLsof :: Annex ()
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needLsof = error $ unlines
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[ "The lsof command is needed for watch mode to be safe, and is not in PATH."
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, "To override lsof checks to ensure that files are not open for writing"
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, "when added to the annex, you can use --force"
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, "Be warned: This can corrupt data in the annex, and make fsck complain."
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]
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{- A special exception that can be thrown to pause or resume the watcher. -}
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data WatcherException = PauseWatcher | ResumeWatcher
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deriving (Show, Eq, Typeable)
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instance E.Exception WatcherException
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watchThread :: NamedThread
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watchThread = namedThread "Watcher" $
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ifM (liftAnnex $ annexAutoCommit <$> Annex.getGitConfig)
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( runWatcher
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, waitFor ResumeWatcher runWatcher
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)
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runWatcher :: Assistant ()
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runWatcher = do
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startup <- asIO1 startupScan
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direct <- liftAnnex isDirect
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addhook <- hook $ if direct then onAddDirect else onAdd
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delhook <- hook onDel
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addsymlinkhook <- hook $ onAddSymlink direct
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deldirhook <- hook onDelDir
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errhook <- hook onErr
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let hooks = mkWatchHooks
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{ addHook = addhook
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, delHook = delhook
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, addSymlinkHook = addsymlinkhook
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, delDirHook = deldirhook
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, errHook = errhook
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}
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handle <- liftIO $ watchDir "." ignored hooks startup
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debug [ "watching", "."]
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{- Let the DirWatcher thread run until signalled to pause it,
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- then wait for a resume signal, and restart. -}
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waitFor PauseWatcher $ do
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liftIO $ stopWatchDir handle
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waitFor ResumeWatcher runWatcher
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where
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hook a = Just <$> asIO2 (runHandler a)
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waitFor :: WatcherException -> Assistant () -> Assistant ()
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waitFor sig next = do
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r <- liftIO $ (E.try pause :: IO (Either E.SomeException ()))
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case r of
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Left e -> case E.fromException e of
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Just s
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| s == sig -> next
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_ -> noop
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_ -> noop
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where
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pause = runEvery (Seconds 86400) noop
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{- Initial scartup scan. The action should return once the scan is complete. -}
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startupScan :: IO a -> Assistant a
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startupScan scanner = do
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liftAnnex $ showAction "scanning"
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alertWhile' startupScanAlert $ do
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r <- liftIO $ scanner
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-- Notice any files that were deleted before
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-- watching was started.
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top <- liftAnnex $ fromRepo Git.repoPath
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(fs, cleanup) <- liftAnnex $ inRepo $ LsFiles.deleted [top]
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forM_ fs $ \f -> do
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liftAnnex $ Annex.Queue.addUpdateIndex =<<
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inRepo (Git.UpdateIndex.unstageFile f)
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maybe noop recordChange =<< madeChange f RmChange
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void $ liftIO $ cleanup
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liftAnnex $ showAction "started"
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liftIO $ putStrLn ""
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modifyDaemonStatus_ $ \s -> s { scanComplete = True }
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return (True, r)
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ignored :: FilePath -> Bool
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ignored = ig . takeFileName
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where
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ig ".git" = True
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ig ".gitignore" = True
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ig ".gitattributes" = True
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#ifdef darwin_HOST_OS
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ig ".DS_Store" = True
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#endif
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ig _ = False
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type Handler = FilePath -> Maybe FileStatus -> Assistant (Maybe Change)
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{- Runs an action handler, and if there was a change, adds it to the ChangeChan.
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-
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- Exceptions are ignored, otherwise a whole watcher thread could be crashed.
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-}
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runHandler :: Handler -> FilePath -> Maybe FileStatus -> Assistant ()
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runHandler handler file filestatus = void $ do
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r <- tryIO <~> handler file filestatus
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case r of
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Left e -> liftIO $ print e
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Right Nothing -> noop
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Right (Just change) -> do
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-- Just in case the commit thread is not
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-- flushing the queue fast enough.
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liftAnnex $ Annex.Queue.flushWhenFull
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recordChange change
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onAdd :: Handler
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onAdd file filestatus
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| maybe False isRegularFile filestatus = pendingAddChange file
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| otherwise = noChange
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{- In direct mode, add events are received for both new files, and
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- modified existing files. Or, in some cases, existing files that have not
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- really been modified. -}
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onAddDirect :: Handler
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onAddDirect file fs = do
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debug ["add direct", file]
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v <- liftAnnex $ catKeyFile file
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case (v, fs) of
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(Just key, Just filestatus) ->
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ifM (liftAnnex $ sameFileStatus key filestatus)
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( noChange
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, do
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liftAnnex $ changedDirect key file
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pendingAddChange file
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)
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_ -> pendingAddChange file
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{- A symlink might be an arbitrary symlink, which is just added.
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- Or, if it is a git-annex symlink, ensure it points to the content
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- before adding it.
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-}
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onAddSymlink :: Bool -> Handler
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onAddSymlink isdirect file filestatus = go =<< liftAnnex (Backend.lookupFile file)
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where
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go (Just (key, _)) = do
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when isdirect $
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liftAnnex $ void $ addAssociatedFile key file
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link <- liftAnnex $ calcGitLink file key
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ifM ((==) (Just link) <$> liftIO (catchMaybeIO $ readSymbolicLink file))
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( ensurestaged (Just link) (Just key) =<< getDaemonStatus
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, do
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unless isdirect $ do
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liftIO $ removeFile file
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liftAnnex $ Backend.makeAnnexLink link file
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addlink link (Just key)
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)
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go Nothing = do -- other symlink
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mlink <- liftIO (catchMaybeIO $ readSymbolicLink file)
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ensurestaged mlink Nothing =<< getDaemonStatus
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{- This is often called on symlinks that are already
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- staged correctly. A symlink may have been deleted
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- and being re-added, or added when the watcher was
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- not running. So they're normally restaged to make sure.
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-
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- As an optimisation, during the startup scan, avoid
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- restaging everything. Only links that were created since
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- the last time the daemon was running are staged.
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- (If the daemon has never ran before, avoid staging
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- links too.)
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-}
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ensurestaged (Just link) mk daemonstatus
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| scanComplete daemonstatus = addlink link mk
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| otherwise = case filestatus of
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Just s
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| not (afterLastDaemonRun (statusChangeTime s) daemonstatus) -> noChange
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_ -> addlink link mk
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ensurestaged Nothing _ _ = noChange
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{- For speed, tries to reuse the existing blob for symlink target. -}
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addlink link mk = do
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debug ["add symlink", file]
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liftAnnex $ do
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v <- catObjectDetails $ Ref $ ':':file
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case v of
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Just (currlink, sha)
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| s2w8 link == L.unpack currlink ->
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stageSymlink file sha
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_ -> stageSymlink file =<< hashSymlink link
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madeChange file $ LinkChange mk
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onDel :: Handler
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onDel file _ = do
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debug ["file deleted", file]
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liftAnnex $
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Annex.Queue.addUpdateIndex =<<
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inRepo (Git.UpdateIndex.unstageFile file)
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madeChange file RmChange
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{- A directory has been deleted, or moved, so tell git to remove anything
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- that was inside it from its cache. Since it could reappear at any time,
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- use --cached to only delete it from the index.
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-
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- This queues up a lot of RmChanges, which assists the Committer in
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- pairing up renamed files when the directory was renamed. -}
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onDelDir :: Handler
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onDelDir dir _ = do
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debug ["directory deleted", dir]
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(fs, clean) <- liftAnnex $ inRepo $ LsFiles.deleted [dir]
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liftAnnex $ forM_ fs $ \f -> Annex.Queue.addUpdateIndex =<<
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inRepo (Git.UpdateIndex.unstageFile f)
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-- Get the events queued up as fast as possible, so the
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-- committer sees them all in one block.
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now <- liftIO getCurrentTime
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forM_ fs $ \f -> recordChange $ Change now f RmChange
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void $ liftIO $ clean
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liftAnnex $ Annex.Queue.flushWhenFull
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noChange
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{- Called when there's an error with inotify or kqueue. -}
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onErr :: Handler
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onErr msg _ = do
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liftAnnex $ warning msg
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void $ addAlert $ warningAlert "watcher" msg
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noChange
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