git-annex/Assistant/CredPairCache.hs
2015-01-21 12:50:09 -04:00

53 lines
1.4 KiB
Haskell

{- git-annex assistant CredPair cache.
-
- Copyright 2014 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU GPL version 3 or higher.
-}
{-# LANGUAGE BangPatterns #-}
module Assistant.CredPairCache (
cacheCred,
getCachedCred,
expireCachedCred,
) where
import Assistant.Types.CredPairCache
import Types.Creds
import Assistant.Common
import Utility.ThreadScheduler
import qualified Data.Map as M
import Control.Concurrent
{- Caches a CredPair, but only for a limited time, after which it
- will expire.
-
- Note that repeatedly caching the same CredPair
- does not reset its expiry time.
-}
cacheCred :: CredPair -> Seconds -> Assistant ()
cacheCred (login, password) expireafter = do
cache <- getAssistant credPairCache
liftIO $ do
changeStrict cache $ M.insert login password
void $ forkIO $ do
threadDelaySeconds expireafter
changeStrict cache $ M.delete login
getCachedCred :: Login -> Assistant (Maybe Password)
getCachedCred login = do
cache <- getAssistant credPairCache
liftIO $ M.lookup login <$> readMVar cache
expireCachedCred :: Login -> Assistant ()
expireCachedCred login = do
cache <- getAssistant credPairCache
liftIO $ changeStrict cache $ M.delete login
{- Update map strictly to avoid keeping references to old creds in memory. -}
changeStrict :: CredPairCache -> (M.Map Login Password -> M.Map Login Password) -> IO ()
changeStrict cache a = modifyMVar_ cache $ \m -> do
let !m' = a m
return m'