68 lines
1.7 KiB
Haskell
68 lines
1.7 KiB
Haskell
{- git-annex "WORM" backend -- Write Once, Read Many
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-
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- Copyright 2010 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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module Backend.WORM (backends) where
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import Control.Monad.State
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import System.FilePath
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import System.Posix.Files
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import System.Directory
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import Data.Maybe
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import qualified Backend.File
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import BackendClass
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import Locations
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import qualified Annex
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import Content
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import Messages
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import Types
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import Key
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backends :: [Backend Annex]
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backends = [backend]
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backend :: Backend Annex
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backend = Backend.File.backend {
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name = "WORM",
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getKey = keyValue,
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fsckKey = Backend.File.checkKey checkKeySize
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}
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{- The key includes the file size, modification time, and the
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- basename of the filename.
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-
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- That allows multiple files with the same names to have different keys,
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- while also allowing a file to be moved around while retaining the
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- same key.
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-}
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keyValue :: FilePath -> Annex (Maybe Key)
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keyValue file = do
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stat <- liftIO $ getFileStatus file
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return $ Just $ Key {
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keyName = takeFileName file,
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keyBackendName = name backend,
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keySize = Just $ fromIntegral $ fileSize stat,
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keyMtime = Just $ modificationTime stat
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}
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{- The size of the data for a key is checked against the size encoded in
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- the key's metadata. -}
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checkKeySize :: Key -> Annex Bool
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checkKeySize key = do
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g <- Annex.gitRepo
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let file = gitAnnexLocation g key
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present <- liftIO $ doesFileExist file
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if not present
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then return True
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else do
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s <- liftIO $ getFileStatus file
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if fromIntegral (fileSize s) == fromJust (keySize key)
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then return True
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else do
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dest <- moveBad key
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warning $ "Bad file size; moved to " ++ dest
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return False
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