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|
{- Posix lock files, using lock pools.
-
- Copyright 2015 Joey Hess <id@joeyh.name>
-
- License: BSD-2-clause
-}
module Utility.LockPool.Posix (
P.LockFile,
LockHandle,
lockShared,
lockExclusive,
tryLockShared,
tryLockExclusive,
checkLocked,
getLockStatus,
LockStatus(..),
dropLock,
checkSaneLock,
) where
import qualified Utility.LockFile.Posix as F
import Utility.LockFile.LockStatus
import qualified Utility.LockPool.STM as P
import Utility.LockPool.STM (LockFile, LockMode(..))
import Utility.LockPool.LockHandle
import System.IO
import System.Posix
import Data.Maybe
import Control.Applicative
import Prelude
-- Takes a shared lock, blocking until the lock is available.
lockShared :: Maybe FileMode -> LockFile -> IO LockHandle
lockShared mode file = makeLockHandle
(P.waitTakeLock P.lockPool file LockShared)
(mk <$> F.lockShared mode file)
-- Takes an exclusive lock, blocking until the lock is available.
lockExclusive :: Maybe FileMode -> LockFile -> IO LockHandle
lockExclusive mode file = makeLockHandle
(P.waitTakeLock P.lockPool file LockExclusive)
(mk <$> F.lockExclusive mode file)
-- Tries to take a shared lock, but does not block.
tryLockShared :: Maybe FileMode -> LockFile -> IO (Maybe LockHandle)
tryLockShared mode file = tryMakeLockHandle
(P.tryTakeLock P.lockPool file LockShared)
(fmap mk <$> F.tryLockShared mode file)
-- Tries to take an exclusive lock, but does not block.
tryLockExclusive :: Maybe FileMode -> LockFile -> IO (Maybe LockHandle)
tryLockExclusive mode file = tryMakeLockHandle
(P.tryTakeLock P.lockPool file LockExclusive)
(fmap mk <$> F.tryLockExclusive mode file)
-- Returns Nothing when the file doesn't exist, for cases where
-- that is different from it not being locked.
checkLocked :: LockFile -> IO (Maybe Bool)
checkLocked file = P.getLockStatus P.lockPool file
(pure (Just True))
(F.checkLocked file)
getLockStatus :: LockFile -> IO LockStatus
getLockStatus file = P.getLockStatus P.lockPool file
(StatusLockedBy <$> getProcessID)
(F.getLockStatus file)
mk :: F.LockHandle -> FileLockOps
mk h = FileLockOps
{ fDropLock = F.dropLock h
, fCheckSaneLock = \f -> F.checkSaneLock f h
}
|
