git-annex/Annex/InodeSentinal.hs
Joey Hess 3311c48631
move InodeSentinal from direct mode code to its own module
Will be used outside of direct mode for v6 unlocked files, and is already
used outside of direct mode when adding files to annex.
2015-12-09 15:52:11 -04:00

67 lines
2 KiB
Haskell

{- git-annex inode sentinal file
-
- Copyright 2012-2015 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU GPL version 3 or higher.
-}
{-# LANGUAGE CPP #-}
module Annex.InodeSentinal where
import Common.Annex
import qualified Annex
import Utility.InodeCache
import Annex.Perms
{- Some filesystems get new inodes each time they are mounted.
- In order to work on such a filesystem, a sentinal file is used to detect
- when the inodes have changed.
-
- If the sentinal file does not exist, we have to assume that the
- inodes have changed.
-}
inodesChanged :: Annex Bool
inodesChanged = sentinalInodesChanged <$> sentinalStatus
withTSDelta :: (TSDelta -> Annex a) -> Annex a
withTSDelta a = a =<< getTSDelta
getTSDelta :: Annex TSDelta
#ifdef mingw32_HOST_OS
getTSDelta = sentinalTSDelta <$> sentinalStatus
#else
getTSDelta = pure noTSDelta -- optimisation
#endif
sentinalStatus :: Annex SentinalStatus
sentinalStatus = maybe check return =<< Annex.getState Annex.sentinalstatus
where
check = do
sc <- liftIO . checkSentinalFile =<< annexSentinalFile
Annex.changeState $ \s -> s { Annex.sentinalstatus = Just sc }
return sc
{- The sentinal file is only created when first initializing a repository.
- If there are any annexed objects in the repository already, creating
- the file would invalidate their inode caches. -}
createInodeSentinalFile :: Bool -> Annex ()
createInodeSentinalFile evenwithobjects =
unlessM (alreadyexists <||> hasobjects) $ do
s <- annexSentinalFile
createAnnexDirectory (parentDir (sentinalFile s))
liftIO $ writeSentinalFile s
where
alreadyexists = liftIO. sentinalFileExists =<< annexSentinalFile
hasobjects
| evenwithobjects = pure False
| otherwise = liftIO . doesDirectoryExist =<< fromRepo gitAnnexObjectDir
annexSentinalFile :: Annex SentinalFile
annexSentinalFile = do
sentinalfile <- fromRepo gitAnnexInodeSentinal
sentinalcachefile <- fromRepo gitAnnexInodeSentinalCache
return SentinalFile
{ sentinalFile = sentinalfile
, sentinalCacheFile = sentinalcachefile
}