110 lines
3.4 KiB
Haskell
110 lines
3.4 KiB
Haskell
{- git-annex inode sentinal file
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-
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- Copyright 2012-2015 Joey Hess <id@joeyh.name>
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-
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- Licensed under the GNU AGPL version 3 or higher.
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-}
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{-# LANGUAGE CPP #-}
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{-# LANGUAGE OverloadedStrings #-}
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module Annex.InodeSentinal where
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import Annex.Common
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import qualified Annex
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import Utility.InodeCache
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import Annex.Perms
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{- If the sendinal shows the inodes have changed, only the size and mtime
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- are compared. -}
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compareInodeCaches :: InodeCache -> InodeCache -> Annex Bool
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compareInodeCaches x y
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| compareStrong x y = return True
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| otherwise = ifM inodesChanged
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( return $ compareWeak x y
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, return False
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)
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compareInodeCachesWith :: Annex InodeComparisonType
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compareInodeCachesWith = ifM inodesChanged ( return Weakly, return Strongly )
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{- Checks if one of the provided old InodeCache matches the current
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- version of a file. -}
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sameInodeCache :: RawFilePath -> [InodeCache] -> Annex Bool
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sameInodeCache file [] = do
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fastDebug "Annex.InodeSentinal" $
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fromRawFilePath file ++ " inode cache empty"
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return False
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sameInodeCache file old = go =<< withTSDelta (liftIO . genInodeCache file)
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where
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go Nothing = do
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fastDebug "Annex.InodeSentinal" $
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fromRawFilePath file ++ " not present, cannot compare with inode cache"
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return False
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go (Just curr) = ifM (elemInodeCaches curr old)
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( return True
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, do
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fastDebug "Annex.InodeSentinal" $
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fromRawFilePath file ++ " (" ++ show curr ++ ") does not match inode cache (" ++ show old ++ ")"
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return False
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)
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elemInodeCaches :: InodeCache -> [InodeCache] -> Annex Bool
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elemInodeCaches _ [] = return False
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elemInodeCaches c (l:ls) = ifM (compareInodeCaches c l)
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( return True
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, elemInodeCaches c ls
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)
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{- Some filesystems get new inodes each time they are mounted.
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- In order to work on such a filesystem, a sentinal file is used to detect
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- when the inodes have changed.
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-
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- If the sentinal file does not exist, we have to assume that the
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- inodes have changed.
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-}
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inodesChanged :: Annex Bool
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inodesChanged = sentinalInodesChanged <$> sentinalStatus
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withTSDelta :: (TSDelta -> Annex a) -> Annex a
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withTSDelta a = a =<< getTSDelta
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getTSDelta :: Annex TSDelta
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#ifdef mingw32_HOST_OS
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getTSDelta = sentinalTSDelta <$> sentinalStatus
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#else
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getTSDelta = pure noTSDelta -- optimisation
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#endif
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sentinalStatus :: Annex SentinalStatus
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sentinalStatus = maybe check return =<< Annex.getState Annex.sentinalstatus
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where
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check = do
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sc <- liftIO . checkSentinalFile =<< annexSentinalFile
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Annex.changeState $ \s -> s { Annex.sentinalstatus = Just sc }
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return sc
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{- The sentinal file is only created when first initializing a repository.
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- If there are any annexed objects in the repository already, creating
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- the file would invalidate their inode caches. -}
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createInodeSentinalFile :: Bool -> Annex ()
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createInodeSentinalFile evenwithobjects =
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unlessM (alreadyexists <||> hasobjects) $ do
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s <- annexSentinalFile
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createAnnexDirectory (parentDir (sentinalFile s))
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liftIO $ writeSentinalFile s
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where
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alreadyexists = liftIO. sentinalFileExists =<< annexSentinalFile
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hasobjects
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| evenwithobjects = pure False
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| otherwise = liftIO . doesDirectoryExist . fromRawFilePath
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=<< fromRepo gitAnnexObjectDir
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annexSentinalFile :: Annex SentinalFile
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annexSentinalFile = do
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sentinalfile <- fromRepo gitAnnexInodeSentinal
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sentinalcachefile <- fromRepo gitAnnexInodeSentinalCache
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return SentinalFile
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{ sentinalFile = sentinalfile
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, sentinalCacheFile = sentinalcachefile
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}
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