git-annex/RemoteDaemon/Common.hs
Joey Hess 40ecf58d4b
update licenses from GPL to AGPL
This does not change the overall license of the git-annex program, which
was already AGPL due to a number of sources files being AGPL already.

Legally speaking, I'm adding a new license under which these files are
now available; I already released their current contents under the GPL
license. Now they're dual licensed GPL and AGPL. However, I intend
for all my future changes to these files to only be released under the
AGPL license, and I won't be tracking the dual licensing status, so I'm
simply changing the license statement to say it's AGPL.

(In some cases, others wrote parts of the code of a file and released it
under the GPL; but in all cases I have contributed a significant portion
of the code in each file and it's that code that is getting the AGPL
license; the GPL license of other contributors allows combining with
AGPL code.)
2019-03-13 15:48:14 -04:00

71 lines
2 KiB
Haskell

{- git-remote-daemon utilities
-
- Copyright 2014-2016 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
module RemoteDaemon.Common
( liftAnnex
, inLocalRepo
, checkShouldFetch
, ConnectionStatus(..)
, robustConnection
) where
import qualified Annex
import Annex.Common
import RemoteDaemon.Types
import qualified Git
import Annex.CatFile
import Utility.ThreadScheduler
import Control.Concurrent
-- Runs an Annex action. Long-running actions should be avoided,
-- since only one liftAnnex can be running at a time, across all
-- transports.
liftAnnex :: TransportHandle -> Annex a -> IO a
liftAnnex (TransportHandle _ annexstate) a = do
st <- takeMVar annexstate
(r, st') <- Annex.run st a
putMVar annexstate st'
return r
inLocalRepo :: TransportHandle -> (Git.Repo -> IO a) -> IO a
inLocalRepo (TransportHandle (LocalRepo g) _) a = a g
-- Check if some shas should be fetched from the remote,
-- and presumably later merged.
checkShouldFetch :: RemoteGitConfig -> TransportHandle -> [Git.Sha] -> IO Bool
checkShouldFetch gc transporthandle shas
| remoteAnnexPull gc = checkNewShas transporthandle shas
| otherwise = return False
-- Check if any of the shas are actally new in the local git repo,
-- to avoid unnecessary fetching.
checkNewShas :: TransportHandle -> [Git.Sha] -> IO Bool
checkNewShas transporthandle = check
where
check [] = return True
check (r:rs) = maybe (check rs) (const $ return False)
=<< liftAnnex transporthandle (catObjectDetails r)
data ConnectionStatus = ConnectionStopping | ConnectionClosed
{- Make connection robust, retrying on error, with exponential backoff. -}
robustConnection :: Int -> IO ConnectionStatus -> IO ()
robustConnection backoff a =
caught =<< a `catchNonAsync` (const $ return ConnectionClosed)
where
caught ConnectionStopping = return ()
caught ConnectionClosed = do
threadDelaySeconds (Seconds backoff)
robustConnection increasedbackoff a
increasedbackoff
| b2 > maxbackoff = maxbackoff
| otherwise = b2
where
b2 = backoff * 2
maxbackoff = 3600 -- one hour