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|
{-# LANGUAGE CPP #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE RankNTypes #-}
module Main (main) where
import Control.Concurrent (threadDelay)
import Control.Exception (bracket)
import System.Environment (getArgs)
import System.IO (Handle, IOMode (ReadWriteMode), hClose, openFile)
import qualified Data.ByteString as BS
import qualified Data.ByteString.Char8 as BS8
import Lukko
#ifdef HAS_OFD_LOCKING
import qualified Lukko.OFD as OFD
#endif
#ifdef HAS_FLOCK
import qualified Lukko.FLock as FLock
#endif
main :: IO ()
main = withArgs $ \withLock -> do
putStrLn "starting..."
withLock $ do
contents <- BS.readFile "test-actual"
threadDelay 10000 -- 10 ms
BS.writeFile "test-actual" $ BS.append contents $ BS8.pack "another line\n"
withArgs
:: ((forall r. IO r -> IO r) -> IO ())
-> IO ()
withArgs k = do
args <- getArgs
case args of
["default"] -> k (genWithLock hLock hUnlock "test-lock")
#ifdef HAS_OFD_LOCKING
["ofd"] -> k (genWithLock OFD.hLock OFD.hUnlock "test-lock")
#endif
#ifdef HAS_FLOCK
["flock"] -> k (genWithLock FLock.hLock FLock.hUnlock "test-lock")
#endif
["noop"] -> k (genWithLock noOpLock noOpUnlock "test-lock")
_ -> putStrLn "Unknown paramters. Doing nothing."
-------------------------------------------------------------------------------
-- copy pasted
-------------------------------------------------------------------------------
noOpLock :: Handle -> LockMode -> IO ()
noOpLock _ _ = return ()
noOpUnlock :: Handle -> IO ()
noOpUnlock _ = return ()
genWithLock
:: (Handle -> LockMode -> IO ())
-> (Handle -> IO ())
-> FilePath
-> IO a
-> IO a
genWithLock implLock implUnlock fp action =
bracket takeLock releaseLock (const action)
where
takeLock = do
h <- openFile fp ReadWriteMode
implLock h ExclusiveLock
return h
releaseLock :: Handle -> IO ()
releaseLock h = do
implUnlock h
hClose h
|
