39 lines
1 KiB
Haskell
39 lines
1 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 (backend) 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 qualified Data.ByteString.Lazy.Char8 as B
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import qualified Backend.File
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import TypeInternals
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import Utility
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backend = Backend.File.backend {
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name = "WORM",
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getKey = keyValue
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}
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-- The key is formed from 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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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 ((name backend), key stat)
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where
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key stat = uniqueid stat ++ sep ++ base
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uniqueid stat = (show $ modificationTime stat) ++ sep ++
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(show $ fileSize stat)
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base = takeFileName file
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sep = ":"
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