97 lines
2.3 KiB
Haskell
97 lines
2.3 KiB
Haskell
{- git-annex SHA abstract backend
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-
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- Copyright 2011 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.SHA (backends) where
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import Control.Monad.State
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import Data.String.Utils
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import System.Cmd.Utils
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import System.IO
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import System.Directory
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import Data.Maybe
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import System.Posix.Files
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import qualified Backend.File
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import BackendClass
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import Messages
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import qualified Annex
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import Locations
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import Content
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import Types
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import Utility
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import qualified SysConfig
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import Key
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type SHASize = Int
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backends :: [Backend Annex]
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-- order is slightly significant; want sha1 first ,and more general
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-- sizes earlier
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backends = catMaybes $ map genBackend [1, 256, 512, 224, 384]
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genBackend :: SHASize -> Maybe (Backend Annex)
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genBackend size
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| shaCommand size /= "" = Just b
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| otherwise = Nothing
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where
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b = Backend.File.backend
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{ name = shaName size
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, getKey = keyValue size
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, fsckKey = Backend.File.checkKey $ checkKeyChecksum size
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}
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shaCommand :: SHASize -> String
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shaCommand 1 = SysConfig.sha1
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shaCommand 256 = SysConfig.sha256
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shaCommand 224 = SysConfig.sha224
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shaCommand 384 = SysConfig.sha384
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shaCommand 512 = SysConfig.sha512
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shaCommand _ = ""
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shaName :: SHASize -> String
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shaName size = "SHA" ++ show size
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shaN :: SHASize -> FilePath -> Annex String
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shaN size file = do
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showNote "checksum..."
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liftIO $ pOpen ReadFromPipe command (toCommand [File file]) $ \h -> do
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line <- hGetLine h
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let bits = split " " line
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if null bits
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then error $ command ++ " parse error"
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else return $ head bits
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where
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command = shaCommand size
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{- A key is a checksum of its contents. -}
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keyValue :: SHASize -> FilePath -> Annex (Maybe Key)
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keyValue size file = do
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s <- shaN size file
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stat <- liftIO $ getFileStatus file
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return $ Just $ stubKey {
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keyName = s,
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keyBackendName = shaName size,
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keySize = Just $ fromIntegral $ fileSize stat
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}
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-- A key's checksum is checked during fsck.
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checkKeyChecksum :: SHASize -> Key -> Annex Bool
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checkKeyChecksum size key = do
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g <- Annex.gitRepo
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fast <- Annex.getState Annex.fast
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let file = gitAnnexLocation g key
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present <- liftIO $ doesFileExist file
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if (not present || fast)
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then return True
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else do
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s <- shaN size file
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if s == keyName 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 content; moved to " ++ dest
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return False
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