git-annex/Remote/Web.hs
Joey Hess 7225c2bfc0 record transfer information on local git remotes
In order to record a semi-useful filename associated with the key,
this required plumbing the filename all the way through to the remotes'
storeKey and retrieveKeyFile.

Note that there is potential for deadlock here, narrowly avoided.
Suppose the repos are A and B. A sends file foo to B, and at the same
time, B gets file foo from A. So, A locks its upload transfer info file,
and then locks B's download transfer info file. At the same time,
B is taking the two locks in the opposite order. This is only not a
deadlock because the lock code does not wait, and aborts. So one of A or
B's transfers will be aborted and the other transfer will continue.
Whew!
2012-07-01 17:15:11 -04:00

87 lines
2.1 KiB
Haskell

{- Web remotes.
-
- Copyright 2011 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Remote.Web (remote) where
import Common.Annex
import Types.Remote
import qualified Git
import qualified Git.Construct
import Annex.Content
import Config
import Logs.Web
import qualified Utility.Url as Url
import Types.Key
remote :: RemoteType
remote = RemoteType {
typename = "web",
enumerate = list,
generate = gen,
setup = error "not supported"
}
-- There is only one web remote, and it always exists.
-- (If the web should cease to exist, remove this module and redistribute
-- a new release to the survivors by carrier pigeon.)
list :: Annex [Git.Repo]
list = do
r <- liftIO $ Git.Construct.remoteNamed "web" Git.Construct.fromUnknown
return [r]
gen :: Git.Repo -> UUID -> Maybe RemoteConfig -> Annex Remote
gen r _ _ =
return Remote {
uuid = webUUID,
cost = expensiveRemoteCost,
name = Git.repoDescribe r,
storeKey = uploadKey,
retrieveKeyFile = downloadKey,
retrieveKeyFileCheap = downloadKeyCheap,
removeKey = dropKey,
hasKey = checkKey,
hasKeyCheap = False,
whereisKey = Just getUrls,
config = Nothing,
repo = r,
remotetype = remote
}
downloadKey :: Key -> AssociatedFile -> FilePath -> Annex Bool
downloadKey key _file dest = get =<< getUrls key
where
get [] = do
warning "no known url"
return False
get urls = do
showOutput -- make way for download progress bar
downloadUrl urls dest
downloadKeyCheap :: Key -> FilePath -> Annex Bool
downloadKeyCheap _ _ = return False
uploadKey :: Key -> AssociatedFile -> Annex Bool
uploadKey _ _ = do
warning "upload to web not supported"
return False
dropKey :: Key -> Annex Bool
dropKey _ = do
warning "removal from web not supported"
return False
checkKey :: Key -> Annex (Either String Bool)
checkKey key = do
us <- getUrls key
if null us
then return $ Right False
else return . Right =<< checkKey' key us
checkKey' :: Key -> [URLString] -> Annex Bool
checkKey' key us = untilTrue us $ \u -> do
showAction $ "checking " ++ u
headers <- getHttpHeaders
liftIO $ Url.check u headers (keySize key)