-- Hoogle documentation, generated by Haddock -- See Hoogle, http://www.haskell.org/hoogle/ -- | File locking -- -- This package provides access to platform dependent file locking APIs: -- -- -- -- There are alternative file locking packages: -- -- -- -- Lukko means lock in Finnish. -- -- Submodules Lukko.OFD, Lukko.Windows etc are available -- based on following conditions. -- -- 
--   if os(windows)
--     cpp-options: -DHAS_WINDOWS_LOCK
--   
--   elif (os(linux) && flag(ofd-locking))
--     cpp-options: -DHAS_OFD_LOCKING
--     cpp-options: -DHAS_FLOCK
--   
--   elif !(os(solaris) || os(aix))
--     cpp-options: -DHAS_FLOCK
--
-- -- Lukko.FLock is available on not (Windows or Solaris or AIX). -- Lukko.NoOp is always available. @package lukko @version 0.1 -- | File locking via POSIX flock. module Lukko.FLock -- | Exception thrown by hLock on non-Windows platforms that don't -- support flock. data FileLockingNotSupported FileLockingNotSupported :: FileLockingNotSupported -- | A constants specifying whether file locking is supported. fileLockingSupported :: Bool -- | Potentially availble lock methods. data FileLockingMethod -- | open file descriptor locking MethodOFD :: FileLockingMethod -- | BSD flock MethodFLock :: FileLockingMethod -- | Windows locking MethodWindows :: FileLockingMethod -- | No-Op (throws FileLockingNotSupported) MethodNoOp :: FileLockingMethod -- | A constant specifying this method fileLockingMethod :: FileLockingMethod -- | Indicates a mode in which a file should be locked. data LockMode SharedLock :: LockMode ExclusiveLock :: LockMode -- | Opaque file descriptor -- -- This is a wrapper over CInt data FD -- | Open file to be used for locking. -- -- 
--   open(path, O_RDWR | O_CREAT);
--
fdOpen :: FilePath -> IO FD -- | Close lock file. -- -- 
--   close(fd);
--
fdClose :: FD -> IO () -- | Lock using OFD locks. fdLock :: FD -> LockMode -> IO () -- | Try to lock using OFD locks. fdTryLock :: FD -> LockMode -> IO Bool -- | Unlock using OFD locks. fdUnlock :: FD -> IO () -- | Lock using OFD locks. hLock :: Handle -> LockMode -> IO () -- | Try to lock using OFD locks. hTryLock :: Handle -> LockMode -> IO Bool -- | Unlock using OFD locks. hUnlock :: Handle -> IO () -- | Non-operating locks. -- -- All functions throw FileLockingNotImplemented. module Lukko.NoOp -- | Exception thrown by hLock on non-Windows platforms that don't -- support flock. data FileLockingNotSupported FileLockingNotSupported :: FileLockingNotSupported -- | A constants specifying whether file locking is supported. fileLockingSupported :: Bool -- | Potentially availble lock methods. data FileLockingMethod -- | open file descriptor locking MethodOFD :: FileLockingMethod -- | BSD flock MethodFLock :: FileLockingMethod -- | Windows locking MethodWindows :: FileLockingMethod -- | No-Op (throws FileLockingNotSupported) MethodNoOp :: FileLockingMethod -- | A constant specifying this method fileLockingMethod :: FileLockingMethod -- | Indicates a mode in which a file should be locked. data LockMode SharedLock :: LockMode ExclusiveLock :: LockMode -- | Opaque file descriptor -- -- This is a wrapper over CInt data FD -- | Open file to be used for locking. -- -- 
--   open(path, O_RDWR | O_CREAT);
--
fdOpen :: FilePath -> IO FD -- | Close lock file. -- -- 
--   close(fd);
--
fdClose :: FD -> IO () -- | No-op implementation. fdLock :: FD -> LockMode -> IO () -- | No-op implementation fdTryLock :: FD -> LockMode -> IO Bool -- | No-op implementation. fdUnlock :: FD -> IO () -- | No-op implementation. hLock :: Handle -> LockMode -> IO () -- | No-op implementation hTryLock :: Handle -> LockMode -> IO Bool -- | No-op implementation. hUnlock :: Handle -> IO () -- | Linux open file descriptor locking. -- -- -- https://www.gnu.org/software/libc/manual/html_node/Open-File-Description-Locks.html -- -- We prefer this over BSD locking (e.g. flock) since the latter appears -- to break in some NFS configurations. Note that we intentionally do not -- try to use ordinary POSIX file locking due to its peculiar semantics -- under multi-threaded environments. module Lukko.OFD -- | Exception thrown by hLock on non-Windows platforms that don't -- support flock. data FileLockingNotSupported FileLockingNotSupported :: FileLockingNotSupported -- | A constants specifying whether file locking is supported. fileLockingSupported :: Bool -- | Potentially availble lock methods. data FileLockingMethod -- | open file descriptor locking MethodOFD :: FileLockingMethod -- | BSD flock MethodFLock :: FileLockingMethod -- | Windows locking MethodWindows :: FileLockingMethod -- | No-Op (throws FileLockingNotSupported) MethodNoOp :: FileLockingMethod -- | A constant specifying this method fileLockingMethod :: FileLockingMethod -- | Indicates a mode in which a file should be locked. data LockMode SharedLock :: LockMode ExclusiveLock :: LockMode -- | Opaque file descriptor -- -- This is a wrapper over CInt data FD -- | Open file to be used for locking. -- -- 
--   open(path, O_RDWR | O_CREAT);
--
fdOpen :: FilePath -> IO FD -- | Close lock file. -- -- 
--   close(fd);
--
fdClose :: FD -> IO () -- | Lock using OFD locks. fdLock :: FD -> LockMode -> IO () -- | Try to lock using OFD locks. fdTryLock :: FD -> LockMode -> IO Bool -- | Unlock using OFD locks. fdUnlock :: FD -> IO () -- | Lock using OFD locks. hLock :: Handle -> LockMode -> IO () -- | Try to lock using OFD locks. hTryLock :: Handle -> LockMode -> IO Bool -- | Unlock using OFD locks. hUnlock :: Handle -> IO () instance Foreign.Storable.Storable Lukko.OFD.FLock -- | Open Handle based locking module Lukko -- | Exception thrown by hLock on non-Windows platforms that don't -- support flock. data FileLockingNotSupported FileLockingNotSupported :: FileLockingNotSupported -- | A constants specifying whether file locking is supported. fileLockingSupported :: Bool -- | Potentially availble lock methods. data FileLockingMethod -- | open file descriptor locking MethodOFD :: FileLockingMethod -- | BSD flock MethodFLock :: FileLockingMethod -- | Windows locking MethodWindows :: FileLockingMethod -- | No-Op (throws FileLockingNotSupported) MethodNoOp :: FileLockingMethod -- | A constant specifying this method fileLockingMethod :: FileLockingMethod -- | Indicates a mode in which a file should be locked. data LockMode SharedLock :: LockMode ExclusiveLock :: LockMode -- | Opaque file descriptor -- -- An int / CInt on unix systems, and HANDLE -- on windows. type FD = FD -- | Open file to be used for locking. fdOpen :: FilePath -> IO FD -- | Close lock file. fdClose :: FD -> IO () -- | Like hLock, but work on "raw" file descriptor, as handled by -- fdOpen and fdClose. fdLock :: FD -> LockMode -> IO () -- | Non-blocking version of fdLock. fdTryLock :: FD -> LockMode -> IO Bool -- | Release a lock taken with fdLock or fdTryLock. fdUnlock :: FD -> IO () -- | Convert GHC Handle to lukko FD. handleToFd :: Handle -> IO FD -- | If a Handle references a file descriptor, attempt to lock -- contents of the underlying file in appropriate mode. If the file is -- already locked in incompatible mode, this function blocks until the -- lock is established. The lock is automatically released upon closing a -- Handle. -- -- Things to be aware of: -- -- 1) This function may block inside a C call. If it does, in order to be -- able to interrupt it with asynchronous exceptions and/or for other -- threads to continue working, you MUST use threaded version of the -- runtime system. -- -- 2) The implementation uses LockFileEx on Windows, open -- file descriptor locks on Linux, and flock otherwise, -- hence all of their caveats also apply here. -- -- 3) On non-Windows plaftorms that don't support flock (e.g. -- Solaris) this function throws FileLockingNotImplemented. We -- deliberately choose to not provide fcntl based locking -- instead because of its broken semantics. hLock :: Handle -> LockMode -> IO () -- | Non-blocking version of hLock. hTryLock :: Handle -> LockMode -> IO Bool -- | Release a lock taken with hLock or hTryLock. hUnlock :: Handle -> IO ()