1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
|
{- Posix lock files, using lock pools.
-
- Copyright 2015 Joey Hess <id@joeyh.name>
-
- License: BSD-2-clause
-}
module Utility.LockPool.Posix (
LockHandle,
lockShared,
lockExclusive,
tryLockExclusive,
checkLocked,
getLockStatus,
dropLock,
checkSaneLock,
) where
import qualified Utility.LockFile.Posix as F
import qualified Utility.LockPool.STM as P
import Utility.LockPool.STM (LockPool, LockFile, LockMode(..))
import Utility.LockPool.LockHandle
import Utility.Monad
import Control.Concurrent.STM
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)
(F.lockShared mode file)
lockExclusive :: Maybe FileMode -> LockFile -> IO LockHandle
lockExclusive mode file = makeLockHandle
(P.waitTakeLock P.lockPool file LockExclusive)
(F.lockExclusive mode file)
tryLockExclusive :: Maybe FileMode -> LockFile -> IO (Maybe LockHandle)
tryLockExclusive mode file = tryMakeLockHandle
(P.tryTakeLock P.lockPool file LockExclusive)
(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 True)
(F.checkLocked file)
getLockStatus :: LockFile -> IO (Maybe ProcessID)
getLockStatus file = P.getLockStatus P.lockPool file getProcessID
(F.getLockStatus file)
checkSaneLock :: LockFile -> LockHandle -> IO Bool
checkSaneLock lockfile (LockHandle _ fh) = F.checkSaneLock lockfile fh
|
