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|
{- Windows lock files, using lock pools.
-
- Copyright 2015 Joey Hess <id@joeyh.name>
-
- License: BSD-2-clause
-}
module Utility.LockPool.Windows (
P.LockFile,
LockHandle,
lockShared,
lockExclusive,
dropLock,
waitToLock,
) where
import qualified Utility.LockFile.Windows as F
import qualified Utility.LockPool.STM as P
import Utility.LockPool.LockHandle
import Utility.LockPool.STM (LockFile, LockMode(..))
{- Tries to lock a file with a shared lock, which allows other processes to
- also lock it shared. Fails if the file is exclusively locked. -}
lockShared :: LockFile -> IO (Maybe LockHandle)
lockShared file = tryMakeLockHandle P.lockPool file
(\p f -> P.tryTakeLock p f LockShared)
(\f -> fmap mk <$> F.lockShared f)
{- Tries to take an exclusive lock on a file. Fails if another process has
- a shared or exclusive lock.
-
- Note that exclusive locking also prevents the file from being opened for
- read or write by any other process. So for advisory locking of a file's
- content, a separate LockFile should be used. -}
lockExclusive :: LockFile -> IO (Maybe LockHandle)
lockExclusive file = tryMakeLockHandle P.lockPool file
(\p f -> P.tryTakeLock p f LockExclusive)
(\f -> fmap mk <$> F.lockExclusive f)
{- If the initial lock fails, this is a BUSY wait, and does not
- guarentee FIFO order of waiters. In other news, Windows is a POS. -}
waitToLock :: IO (Maybe lockhandle) -> IO lockhandle
waitToLock = F.waitToLock
mk :: F.LockHandle -> FileLockOps
mk h = FileLockOps
{ fDropLock = F.dropLock h
}
|
