git-annex/Remote/Directory/LegacyChunked.hs
Joey Hess 1400cbb032 Support for remotes that are chunkable and encryptable.
I'd have liked to keep these two concepts entirely separate,
but that are entagled: Storing a key in an encrypted and chunked remote
need to generate chunk keys, encrypt the keys, chunk the data, encrypt the
chunks, and send them to the remote. Similar for retrieval, etc.

So, here's an implemnetation of all of that.

The total win here is that every remote was implementing encrypted storage
and retrival, and now it can move into this single place. I expect this
to result in several hundred lines of code being removed from git-annex
eventually!

This commit was sponsored by Henrik Ahlgren.
2014-07-26 20:14:31 -04:00

110 lines
4 KiB
Haskell

{- Legacy chunksize support for directory special remote.
-
- Can be removed eventually.
-
- Copyright 2011-2012 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Remote.Directory.LegacyChunked where
import qualified Data.ByteString.Lazy as L
import qualified Data.ByteString as S
import Common.Annex
import Utility.FileMode
import Remote.Helper.ChunkedEncryptable
import qualified Remote.Helper.Chunked.Legacy as Legacy
import Annex.Perms
import Utility.Metered
withCheckedFiles :: (FilePath -> IO Bool) -> FilePath -> (FilePath -> Key -> [FilePath]) -> Key -> ([FilePath] -> IO Bool) -> IO Bool
withCheckedFiles _ [] _locations _ _ = return False
withCheckedFiles check d locations k a = go $ locations d k
where
go [] = return False
go (f:fs) = do
let chunkcount = f ++ Legacy.chunkCount
ifM (check chunkcount)
( do
chunks <- Legacy.listChunks f <$> readFile chunkcount
ifM (allM check chunks)
( a chunks , return False )
, do
chunks <- Legacy.probeChunks f check
if null chunks
then go fs
else a chunks
)
withStoredFiles :: FilePath -> (FilePath -> Key -> [FilePath]) -> Key -> ([FilePath] -> IO Bool) -> IO Bool
withStoredFiles = withCheckedFiles doesFileExist
{- Splits a ByteString into chunks and writes to dests, obeying configured
- chunk size (not to be confused with the L.ByteString chunk size). -}
storeLegacyChunked :: MeterUpdate -> ChunkSize -> [FilePath] -> L.ByteString -> IO [FilePath]
storeLegacyChunked _ _ [] _ = error "bad storeLegacyChunked call"
storeLegacyChunked meterupdate chunksize alldests@(firstdest:_) b
| L.null b = do
-- always write at least one file, even for empty
L.writeFile firstdest b
return [firstdest]
| otherwise = storeLegacyChunked' meterupdate chunksize alldests (L.toChunks b) []
storeLegacyChunked' :: MeterUpdate -> ChunkSize -> [FilePath] -> [S.ByteString] -> [FilePath] -> IO [FilePath]
storeLegacyChunked' _ _ [] _ _ = error "ran out of dests"
storeLegacyChunked' _ _ _ [] c = return $ reverse c
storeLegacyChunked' meterupdate chunksize (d:dests) bs c = do
bs' <- withFile d WriteMode $
feed zeroBytesProcessed chunksize bs
storeLegacyChunked' meterupdate chunksize dests bs' (d:c)
where
feed _ _ [] _ = return []
feed bytes sz (l:ls) h = do
let len = S.length l
let s = fromIntegral len
if s <= sz || sz == chunksize
then do
S.hPut h l
let bytes' = addBytesProcessed bytes len
meterupdate bytes'
feed bytes' (sz - s) ls h
else return (l:ls)
storeHelper :: (FilePath -> FilePath -> IO ()) -> Key -> ([FilePath] -> IO [FilePath]) -> FilePath -> FilePath -> IO Bool
storeHelper finalizer key storer tmpdir destdir = do
void $ liftIO $ tryIO $ createDirectoryIfMissing True tmpdir
Legacy.storeChunks key tmpdir destdir storer recorder finalizer
where
recorder f s = do
void $ tryIO $ allowWrite f
writeFile f s
void $ tryIO $ preventWrite f
store :: ChunkSize -> (FilePath -> FilePath -> IO ()) -> Key -> L.ByteString -> MeterUpdate -> FilePath -> FilePath -> IO Bool
store chunksize finalizer k b p = storeHelper finalizer k $ \dests ->
storeLegacyChunked p chunksize dests b
{- Need to get a single ByteString containing every chunk.
- Done very innefficiently, by writing to a temp file.
- :/ This is legacy code..
-}
retrieve :: (FilePath -> Key -> [FilePath]) -> FilePath -> PrepareRetriever
retrieve locations d basek = do
showLongNote "This remote uses the deprecated chunksize setting. So this will be quite slow."
tmpdir <- fromRepo $ gitAnnexTmpMiscDir
createAnnexDirectory tmpdir
let tmp = tmpdir </> keyFile basek ++ ".directorylegacy.tmp"
return $ Just $ \k -> do
void $ withStoredFiles d locations k $ \fs -> do
forM_ fs $
S.appendFile tmp <=< S.readFile
return True
b <- L.readFile tmp
nukeFile tmp
return b
checkPresent :: FilePath -> (FilePath -> Key -> [FilePath]) -> Key -> Annex (Either String Bool)
checkPresent d locations k = liftIO $ catchMsgIO $
withStoredFiles d locations k $
-- withStoredFiles checked that it exists
const $ return True