git-annex/Backend/File.hs
2010-10-14 15:58:53 -04:00

86 lines
2.5 KiB
Haskell

{- git-annex "file" backend
- -}
module Backend.File (backend) where
import Control.Monad.State
import System.IO
import System.Cmd
import System.Exit
import Control.Exception
import BackendTypes
import LocationLog
import Locations
import qualified Remotes
import qualified GitRepo as Git
import Utility
backend = Backend {
name = "file",
getKey = keyValue,
storeFileKey = dummyStore,
retrieveKeyFile = copyKeyFile,
removeKey = dummyRemove,
hasKey = checkKeyFile
}
-- direct mapping from filename to key
keyValue :: FilePath -> Annex (Maybe Key)
keyValue file = return $ Just $ Key file
{- This backend does not really do any independant data storage,
- it relies on the file contents in .git/annex/ in this repo,
- and other accessible repos. So storing a key is
- a no-op. -}
dummyStore :: FilePath -> Key -> Annex (Bool)
dummyStore file key = return True
{- Allow keys to be removed. -}
dummyRemove :: Key -> Annex Bool
dummyRemove url = return True
{- Just check if the .git/annex/ file for the key exists. -}
checkKeyFile :: Key -> Annex Bool
checkKeyFile k = inAnnex backend k
{- Try to find a copy of the file in one of the remotes,
- and copy it over to this one. -}
copyKeyFile :: Key -> FilePath -> Annex (Bool)
copyKeyFile key file = do
remotes <- Remotes.withKey key
trycopy remotes remotes
where
trycopy full [] = error $ "unable to get: " ++ (keyFile key) ++ "\n" ++
"To get that file, need access to one of these remotes: " ++
(Remotes.list full)
trycopy full (r:rs) = do
-- annexLocation needs the git config to have been
-- read for a remote, so do that now,
-- if it hasn't been already
result <- Remotes.tryGitConfigRead r
case (result) of
Nothing -> trycopy full rs
Just r' -> do
result <- liftIO $ (try (copyFromRemote r' key file)::IO (Either SomeException ()))
case (result) of
Left err -> do
liftIO $ hPutStrLn stderr (show err)
trycopy full rs
Right succ -> return True
{- Tries to copy a file from a remote, exception on error. -}
copyFromRemote :: Git.Repo -> Key -> FilePath -> IO ()
copyFromRemote r key file = do
putStrLn $ "copy from " ++ (Git.repoDescribe r ) ++ " " ++ file
if (Git.repoIsLocal r)
then getlocal
else getremote
where
getlocal = do
res <-rawSystem "cp" ["-a", location, file]
if (res == ExitSuccess)
then return ()
else error "cp failed"
getremote = error "get via network not yet implemented!"
location = annexLocation r backend key