git-annex/Remote/Helper/Special.hs
2015-04-03 15:35:18 -04:00

276 lines
8.7 KiB
Haskell

{- helpers for special remotes
-
- Copyright 2011-2014 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Remote.Helper.Special (
findSpecialRemotes,
gitConfigSpecialRemote,
Preparer,
Storer,
Retriever,
Remover,
CheckPresent,
simplyPrepare,
ContentSource,
checkPrepare,
resourcePrepare,
fileStorer,
byteStorer,
fileRetriever,
byteRetriever,
storeKeyDummy,
retreiveKeyFileDummy,
removeKeyDummy,
checkPresentDummy,
SpecialRemoteCfg(..),
specialRemoteCfg,
specialRemote,
specialRemote',
module X
) where
import Common.Annex
import Types.StoreRetrieve
import Types.Remote
import Crypto
import Config.Cost
import Utility.Metered
import Remote.Helper.Chunked as X
import Remote.Helper.Encryptable as X
import Remote.Helper.Messages
import Annex.Content
import Messages.Progress
import qualified Git
import qualified Git.Command
import qualified Git.Construct
import qualified Data.ByteString.Lazy as L
import qualified Data.Map as M
{- Special remotes don't have a configured url, so Git.Repo does not
- automatically generate remotes for them. This looks for a different
- configuration key instead.
-}
findSpecialRemotes :: String -> Annex [Git.Repo]
findSpecialRemotes s = do
m <- fromRepo Git.config
liftIO $ mapM construct $ remotepairs m
where
remotepairs = M.toList . M.filterWithKey match
construct (k,_) = Git.Construct.remoteNamedFromKey k (pure Git.Construct.fromUnknown)
match k _ = startswith "remote." k && endswith (".annex-"++s) k
{- Sets up configuration for a special remote in .git/config. -}
gitConfigSpecialRemote :: UUID -> RemoteConfig -> String -> String -> Annex ()
gitConfigSpecialRemote u c k v = do
set ("annex-"++k) v
set ("annex-uuid") (fromUUID u)
where
set a b = inRepo $ Git.Command.run
[Param "config", Param (configsetting a), Param b]
remotename = fromJust (M.lookup "name" c)
configsetting s = "remote." ++ remotename ++ "." ++ s
-- Use when nothing needs to be done to prepare a helper.
simplyPrepare :: helper -> Preparer helper
simplyPrepare helper _ a = a $ Just helper
-- Use to run a check when preparing a helper.
checkPrepare :: (Key -> Annex Bool) -> helper -> Preparer helper
checkPrepare checker helper k a = ifM (checker k)
( a (Just helper)
, a Nothing
)
-- Use to acquire a resource when preparing a helper.
resourcePrepare :: (Key -> (r -> Annex Bool) -> Annex Bool) -> (r -> helper) -> Preparer helper
resourcePrepare withr helper k a = withr k $ \r ->
a (Just (helper r))
-- A Storer that expects to be provided with a file containing
-- the content of the key to store.
fileStorer :: (Key -> FilePath -> MeterUpdate -> Annex Bool) -> Storer
fileStorer a k (FileContent f) m = a k f m
fileStorer a k (ByteContent b) m = withTmp k $ \f -> do
liftIO $ L.writeFile f b
a k f m
-- A Storer that expects to be provided with a L.ByteString of
-- the content to store.
byteStorer :: (Key -> L.ByteString -> MeterUpdate -> Annex Bool) -> Storer
byteStorer a k c m = withBytes c $ \b -> a k b m
-- A Retriever that writes the content of a Key to a provided file.
-- It is responsible for updating the progress meter as it retrieves data.
fileRetriever :: (FilePath -> Key -> MeterUpdate -> Annex ()) -> Retriever
fileRetriever a k m callback = do
f <- prepTmp k
a f k m
callback (FileContent f)
-- A Retriever that generates a lazy ByteString containing the Key's
-- content, and passes it to a callback action which will fully consume it
-- before returning.
byteRetriever :: (Key -> (L.ByteString -> Annex Bool) -> Annex Bool) -> Retriever
byteRetriever a k _m callback = a k (callback . ByteContent)
{- The base Remote that is provided to specialRemote needs to have
- storeKey, retrieveKeyFile, removeKey, and checkPresent methods,
- but they are never actually used (since specialRemote replaces them).
- Here are some dummy ones.
-}
storeKeyDummy :: Key -> AssociatedFile -> MeterUpdate -> Annex Bool
storeKeyDummy _ _ _ = return False
retreiveKeyFileDummy :: Key -> AssociatedFile -> FilePath -> MeterUpdate -> Annex Bool
retreiveKeyFileDummy _ _ _ _ = return False
removeKeyDummy :: Key -> Annex Bool
removeKeyDummy _ = return False
checkPresentDummy :: Key -> Annex Bool
checkPresentDummy _ = error "missing checkPresent implementation"
type RemoteModifier
= RemoteConfig
-> Preparer Storer
-> Preparer Retriever
-> Preparer Remover
-> Preparer CheckPresent
-> Remote
-> Remote
data SpecialRemoteCfg = SpecialRemoteCfg
{ chunkConfig :: ChunkConfig
, displayProgress :: Bool
}
specialRemoteCfg :: RemoteConfig -> SpecialRemoteCfg
specialRemoteCfg c = SpecialRemoteCfg (getChunkConfig c) True
-- Modifies a base Remote to support both chunking and encryption,
-- which special remotes typically should support.
specialRemote :: RemoteModifier
specialRemote c = specialRemote' (specialRemoteCfg c) c
specialRemote' :: SpecialRemoteCfg -> RemoteModifier
specialRemote' cfg c preparestorer prepareretriever prepareremover preparecheckpresent baser = encr
where
encr = baser
{ storeKey = \k _f p -> cip >>= storeKeyGen k p
, retrieveKeyFile = \k _f d p -> cip >>= retrieveKeyFileGen k d p
, retrieveKeyFileCheap = \k d -> cip >>= maybe
(retrieveKeyFileCheap baser k d)
-- retrieval of encrypted keys is never cheap
(\_ -> return False)
, removeKey = \k -> cip >>= removeKeyGen k
, checkPresent = \k -> cip >>= checkPresentGen k
, cost = maybe
(cost baser)
(const $ cost baser + encryptedRemoteCostAdj)
(extractCipher c)
, getInfo = do
l <- getInfo baser
return $ l ++
[ ("encryption", describeEncryption c)
, ("chunking", describeChunkConfig (chunkConfig cfg))
]
}
cip = cipherKey c
gpgopts = getGpgEncParams encr
safely a = catchNonAsync a (\e -> warning (show e) >> return False)
-- chunk, then encrypt, then feed to the storer
storeKeyGen k p enc = safely $ preparestorer k $ safely . go
where
go (Just storer) = sendAnnex k rollback $ \src ->
displayprogress p k $ \p' ->
storeChunks (uuid baser) chunkconfig k src p'
(storechunk enc storer)
(checkPresent baser)
go Nothing = return False
rollback = void $ removeKey encr k
storechunk Nothing storer k content p = storer k content p
storechunk (Just (cipher, enck)) storer k content p =
withBytes content $ \b ->
encrypt gpgopts cipher (feedBytes b) $
readBytes $ \encb ->
storer (enck k) (ByteContent encb) p
-- call retrieve-r to get chunks; decrypt them; stream to dest file
retrieveKeyFileGen k dest p enc =
safely $ prepareretriever k $ safely . go
where
go (Just retriever) = displayprogress p k $ \p' ->
retrieveChunks retriever (uuid baser) chunkconfig
enck k dest p' (sink dest enc)
go Nothing = return False
enck = maybe id snd enc
removeKeyGen k enc = safely $ prepareremover k $ safely . go
where
go (Just remover) = removeChunks remover (uuid baser) chunkconfig enck k
go Nothing = return False
enck = maybe id snd enc
checkPresentGen k enc = preparecheckpresent k go
where
go (Just checker) = checkPresentChunks checker (uuid baser) chunkconfig enck k
go Nothing = cantCheck baser
enck = maybe id snd enc
chunkconfig = chunkConfig cfg
displayprogress p k a
| displayProgress cfg = metered (Just p) k a
| otherwise = a p
{- Sink callback for retrieveChunks. Stores the file content into the
- provided Handle, decrypting it first if necessary.
-
- If the remote did not store the content using chunks, no Handle
- will be provided, and it's up to us to open the destination file.
-
- Note that when neither chunking nor encryption is used, and the remote
- provides FileContent, that file only needs to be renamed
- into place. (And it may even already be in the right place..)
-}
sink
:: FilePath
-> Maybe (Cipher, EncKey)
-> Maybe Handle
-> Maybe MeterUpdate
-> ContentSource
-> Annex Bool
sink dest enc mh mp content = do
case (enc, mh, content) of
(Nothing, Nothing, FileContent f)
| f == dest -> noop
| otherwise -> liftIO $ moveFile f dest
(Just (cipher, _), _, ByteContent b) ->
decrypt cipher (feedBytes b) $
readBytes write
(Just (cipher, _), _, FileContent f) -> do
withBytes content $ \b ->
decrypt cipher (feedBytes b) $
readBytes write
liftIO $ nukeFile f
(Nothing, _, FileContent f) -> do
withBytes content write
liftIO $ nukeFile f
(Nothing, _, ByteContent b) -> write b
return True
where
write b = case mh of
Just h -> liftIO $ b `streamto` h
Nothing -> liftIO $ bracket opendest hClose (b `streamto`)
streamto b h = case mp of
Just p -> meteredWrite p h b
Nothing -> L.hPut h b
opendest = openBinaryFile dest WriteMode
withBytes :: ContentSource -> (L.ByteString -> Annex a) -> Annex a
withBytes (ByteContent b) a = a b
withBytes (FileContent f) a = a =<< liftIO (L.readFile f)