60 lines
1.3 KiB
Haskell
60 lines
1.3 KiB
Haskell
{- git-annex lock pool
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-
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- Copyright 2012, 2014 Joey Hess <joey@kitenet.net>
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-
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- Licensed under the GNU GPL version 3 or higher.
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-}
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{-# LANGUAGE CPP #-}
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module Annex.LockPool where
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import Common.Annex
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import Annex
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import Types.LockPool
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import qualified Data.Map as M
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#ifndef mingw32_HOST_OS
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import Annex.Perms
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#else
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import Utility.WinLock
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#endif
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{- Create a specified lock file, and takes a shared lock. -}
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lockFile :: FilePath -> Annex ()
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lockFile file = go =<< fromPool file
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where
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go (Just _) = noop -- already locked
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go Nothing = do
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#ifndef mingw32_HOST_OS
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mode <- annexFileMode
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lockhandle <- liftIO $ noUmask mode $
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openFd file ReadOnly (Just mode) defaultFileFlags
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liftIO $ waitToSetLock lockhandle (ReadLock, AbsoluteSeek, 0, 0)
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#else
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lockhandle <- liftIO $ waitToLock $ lockShared file
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#endif
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changePool $ M.insert file lockhandle
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unlockFile :: FilePath -> Annex ()
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unlockFile file = maybe noop go =<< fromPool file
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where
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go lockhandle = do
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#ifndef mingw32_HOST_OS
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liftIO $ closeFd lockhandle
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#else
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liftIO $ dropLock lockhandle
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#endif
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changePool $ M.delete file
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getPool :: Annex LockPool
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getPool = getState lockpool
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fromPool :: FilePath -> Annex (Maybe LockHandle)
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fromPool file = M.lookup file <$> getPool
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changePool :: (LockPool -> LockPool) -> Annex ()
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changePool a = do
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m <- getPool
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changeState $ \s -> s { lockpool = a m }
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