git-annex/Utility/Tmp.hs
Joey Hess ed4fe02896 disable horrible tab warning, needed in every file that Setup.hs pulls in
This is certianly a cabal bug for not passing the build options in the
cabal file when building Setup.hs.

And, why oh why did ghc enable this warning by default? So unhappy with
this choice.
2015-05-10 16:31:50 -04:00

108 lines
3.6 KiB
Haskell

{- Temporary files and directories.
-
- Copyright 2010-2013 Joey Hess <id@joeyh.name>
-
- License: BSD-2-clause
-}
{-# LANGUAGE CPP #-}
{-# OPTIONS_GHC -fno-warn-tabs #-}
module Utility.Tmp where
import System.IO
import System.Directory
import Control.Monad.IfElse
import System.FilePath
import Control.Monad.IO.Class
import Utility.Exception
import Utility.FileSystemEncoding
import Utility.PosixFiles
type Template = String
{- Runs an action like writeFile, writing to a temp file first and
- then moving it into place. The temp file is stored in the same
- directory as the final file to avoid cross-device renames. -}
viaTmp :: (MonadMask m, MonadIO m) => (FilePath -> String -> m ()) -> FilePath -> String -> m ()
viaTmp a file content = bracketIO setup cleanup use
where
(dir, base) = splitFileName file
template = base ++ ".tmp"
setup = do
createDirectoryIfMissing True dir
openTempFile dir template
cleanup (tmpfile, h) = do
_ <- tryIO $ hClose h
tryIO $ removeFile tmpfile
use (tmpfile, h) = do
liftIO $ hClose h
a tmpfile content
liftIO $ rename tmpfile file
{- Runs an action with a tmp file located in the system's tmp directory
- (or in "." if there is none) then removes the file. -}
withTmpFile :: (MonadIO m, MonadMask m) => Template -> (FilePath -> Handle -> m a) -> m a
withTmpFile template a = do
tmpdir <- liftIO $ catchDefaultIO "." getTemporaryDirectory
withTmpFileIn tmpdir template a
{- Runs an action with a tmp file located in the specified directory,
- then removes the file. -}
withTmpFileIn :: (MonadIO m, MonadMask m) => FilePath -> Template -> (FilePath -> Handle -> m a) -> m a
withTmpFileIn tmpdir template a = bracket create remove use
where
create = liftIO $ openTempFile tmpdir template
remove (name, h) = liftIO $ do
hClose h
catchBoolIO (removeFile name >> return True)
use (name, h) = a name h
{- Runs an action with a tmp directory located within the system's tmp
- directory (or within "." if there is none), then removes the tmp
- directory and all its contents. -}
withTmpDir :: (MonadMask m, MonadIO m) => Template -> (FilePath -> m a) -> m a
withTmpDir template a = do
tmpdir <- liftIO $ catchDefaultIO "." getTemporaryDirectory
withTmpDirIn tmpdir template a
{- Runs an action with a tmp directory located within a specified directory,
- then removes the tmp directory and all its contents. -}
withTmpDirIn :: (MonadMask m, MonadIO m) => FilePath -> Template -> (FilePath -> m a) -> m a
withTmpDirIn tmpdir template = bracketIO create remove
where
remove d = whenM (doesDirectoryExist d) $ do
#if mingw32_HOST_OS
-- Windows will often refuse to delete a file
-- after a process has just written to it and exited.
-- Because it's crap, presumably. So, ignore failure
-- to delete the temp directory.
_ <- tryIO $ removeDirectoryRecursive d
return ()
#else
removeDirectoryRecursive d
#endif
create = do
createDirectoryIfMissing True tmpdir
makenewdir (tmpdir </> template) (0 :: Int)
makenewdir t n = do
let dir = t ++ "." ++ show n
either (const $ makenewdir t $ n + 1) (const $ return dir)
=<< tryIO (createDirectory dir)
{- It's not safe to use a FilePath of an existing file as the template
- for openTempFile, because if the FilePath is really long, the tmpfile
- will be longer, and may exceed the maximum filename length.
-
- This generates a template that is never too long.
- (Well, it allocates 20 characters for use in making a unique temp file,
- anyway, which is enough for the current implementation and any
- likely implementation.)
-}
relatedTemplate :: FilePath -> FilePath
relatedTemplate f
| len > 20 = truncateFilePath (len - 20) f
| otherwise = f
where
len = length f