git-annex/Remote/Directory.hs
2012-11-18 18:27:53 -04:00

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{- A "remote" that is just a filesystem directory.
-
- Copyright 2011-2012 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Remote.Directory (remote) where
import qualified Data.ByteString.Lazy as L
import qualified Data.ByteString as S
import qualified Data.Map as M
import qualified Control.Exception as E
import Common.Annex
import Types.Remote
import qualified Git
import Config
import Utility.FileMode
import Remote.Helper.Special
import Remote.Helper.Encryptable
import Remote.Helper.Chunked
import Crypto
import Data.Int
import Annex.Content
remote :: RemoteType
remote = RemoteType {
typename = "directory",
enumerate = findSpecialRemotes "directory",
generate = gen,
setup = directorySetup
}
gen :: Git.Repo -> UUID -> Maybe RemoteConfig -> Annex Remote
gen r u c = do
dir <- getRemoteConfig r "directory" (error "missing directory")
cst <- remoteCost r cheapRemoteCost
let chunksize = chunkSize c
return $ encryptableRemote c
(storeEncrypted dir chunksize)
(retrieveEncrypted dir chunksize)
Remote {
uuid = u,
cost = cst,
name = Git.repoDescribe r,
storeKey = store dir chunksize,
retrieveKeyFile = retrieve dir chunksize,
retrieveKeyFileCheap = retrieveCheap dir chunksize,
removeKey = remove dir chunksize,
hasKey = checkPresent dir chunksize,
hasKeyCheap = True,
whereisKey = Nothing,
config = Nothing,
repo = r,
localpath = Just dir,
readonly = False,
remotetype = remote
}
directorySetup :: UUID -> RemoteConfig -> Annex RemoteConfig
directorySetup u c = do
-- verify configuration is sane
let dir = fromMaybe (error "Specify directory=") $
M.lookup "directory" c
liftIO $ unlessM (doesDirectoryExist dir) $
error $ "Directory does not exist: " ++ dir
c' <- encryptionSetup c
-- The directory is stored in git config, not in this remote's
-- persistant state, so it can vary between hosts.
gitConfigSpecialRemote u c' "directory" dir
return $ M.delete "directory" c'
{- Locations to try to access a given Key in the Directory. -}
locations :: FilePath -> Key -> [FilePath]
locations d k = map (d </>) (keyPaths k)
withCheckedFiles :: (FilePath -> IO Bool) -> ChunkSize -> FilePath -> Key -> ([FilePath] -> IO Bool) -> IO Bool
withCheckedFiles _ _ [] _ _ = return False
withCheckedFiles check Nothing d k a = go $ locations d k
where
go [] = return False
go (f:fs) = ifM (check f) ( a [f] , go fs )
withCheckedFiles check (Just _) d k a = go $ locations d k
where
go [] = return False
go (f:fs) = do
let chunkcount = f ++ chunkCount
ifM (check chunkcount)
( do
chunks <- listChunks f <$> readFile chunkcount
ifM (all id <$> mapM check chunks)
( a chunks , return False )
, go fs
)
withStoredFiles :: ChunkSize -> FilePath -> Key -> ([FilePath] -> IO Bool) -> IO Bool
withStoredFiles = withCheckedFiles doesFileExist
store :: FilePath -> ChunkSize -> Key -> AssociatedFile -> MeterUpdate -> Annex Bool
store d chunksize k _f p = do
src <- inRepo $ gitAnnexLocation k
metered (Just p) k $ \meterupdate ->
storeHelper d chunksize k $ \dests ->
case chunksize of
Nothing -> do
let dest = Prelude.head dests
meteredWriteFile meterupdate dest
=<< L.readFile src
return [dest]
Just _ ->
storeSplit meterupdate chunksize dests
=<< L.readFile src
storeEncrypted :: FilePath -> ChunkSize -> (Cipher, Key) -> Key -> MeterUpdate -> Annex Bool
storeEncrypted d chunksize (cipher, enck) k p = do
src <- inRepo $ gitAnnexLocation k
metered (Just p) k $ \meterupdate ->
storeHelper d chunksize enck $ \dests ->
encrypt cipher (feedFile src) $ readBytes $ \b ->
case chunksize of
Nothing -> do
let dest = Prelude.head dests
meteredWriteFile meterupdate dest b
return [dest]
Just _ -> storeSplit meterupdate chunksize dests b
{- Splits a ByteString into chunks and writes to dests, obeying configured
- chunk size (not to be confused with the L.ByteString chunk size).
- Note: Must always write at least one file, even for empty ByteString. -}
storeSplit :: MeterUpdate -> ChunkSize -> [FilePath] -> L.ByteString -> IO [FilePath]
storeSplit _ Nothing _ _ = error "bad storeSplit call"
storeSplit _ _ [] _ = error "bad storeSplit call"
storeSplit meterupdate (Just chunksize) alldests@(firstdest:_) b
| L.null b = do
-- must always write at least one file, even for empty
L.writeFile firstdest b
return [firstdest]
| otherwise = storeSplit' meterupdate chunksize alldests (L.toChunks b) []
storeSplit' :: MeterUpdate -> Int64 -> [FilePath] -> [S.ByteString] -> [FilePath] -> IO [FilePath]
storeSplit' _ _ [] _ _ = error "ran out of dests"
storeSplit' _ _ _ [] c = return $ reverse c
storeSplit' meterupdate chunksize (d:dests) bs c = do
bs' <- E.bracket (openFile d WriteMode) hClose (feed chunksize bs)
storeSplit' meterupdate chunksize dests bs' (d:c)
where
feed _ [] _ = return []
feed sz (l:ls) h = do
let s = fromIntegral $ S.length l
if s <= sz
then do
S.hPut h l
meterupdate $ toInteger s
feed (sz - s) ls h
else return (l:ls)
storeHelper :: FilePath -> ChunkSize -> Key -> ([FilePath] -> IO [FilePath]) -> Annex Bool
storeHelper d chunksize key storer = check <&&> go
where
basedest = Prelude.head $ locations d key
dir = parentDir basedest
{- The size is not exactly known when encrypting the key;
- this assumes that at least the size of the key is
- needed as free space. -}
check = checkDiskSpace (Just dir) key 0
go = liftIO $ catchBoolIO $ do
createDirectoryIfMissing True dir
allowWrite dir
preventWrite dir `after` storeChunks basedest chunksize storer recorder finalizer
finalizer f dest = do
renameFile f dest
preventWrite dest
recorder f s = do
void $ tryIO $ allowWrite f
writeFile f s
preventWrite f
retrieve :: FilePath -> ChunkSize -> Key -> AssociatedFile -> FilePath -> Annex Bool
retrieve d chunksize k _ f = metered Nothing k $ \meterupdate ->
liftIO $ withStoredFiles chunksize d k $ \files ->
catchBoolIO $ do
meteredWriteFileChunks meterupdate f files $ L.readFile
return True
retrieveEncrypted :: FilePath -> ChunkSize -> (Cipher, Key) -> Key -> FilePath -> Annex Bool
retrieveEncrypted d chunksize (cipher, enck) k f = metered Nothing k $ \meterupdate ->
liftIO $ withStoredFiles chunksize d enck $ \files ->
catchBoolIO $ do
decrypt cipher (feeder files) $
readBytes $ meteredWriteFile meterupdate f
return True
where
feeder files h = forM_ files $ \file -> L.hPut h =<< L.readFile file
retrieveCheap :: FilePath -> ChunkSize -> Key -> FilePath -> Annex Bool
retrieveCheap _ (Just _) _ _ = return False -- no cheap retrieval for chunks
retrieveCheap d _ k f = liftIO $ withStoredFiles Nothing d k go
where
go [file] = catchBoolIO $ createSymbolicLink file f >> return True
go _files = return False
remove :: FilePath -> ChunkSize -> Key -> Annex Bool
remove d chunksize k = liftIO $ withStoredFiles chunksize d k go
where
go = all id <$$> mapM removefile
removefile file = catchBoolIO $ do
let dir = parentDir file
allowWrite dir
removeFile file
_ <- tryIO $ removeDirectory dir
return True
checkPresent :: FilePath -> ChunkSize -> Key -> Annex (Either String Bool)
checkPresent d chunksize k = liftIO $ catchMsgIO $ withStoredFiles chunksize d k $
const $ return True -- withStoredFiles checked that it exists