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|
{- Temporary files and directories.
-
- Copyright 2010-2013 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Utility.Tmp where
import Control.Exception (bracket)
import System.IO
import System.Directory
import Control.Monad.IfElse
import Utility.Exception
import System.FilePath
import Utility.FileSystemEncoding
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 :: (FilePath -> String -> IO ()) -> FilePath -> String -> IO ()
viaTmp a file content = do
let (dir, base) = splitFileName file
createDirectoryIfMissing True dir
(tmpfile, handle) <- openTempFile dir (base ++ ".tmp")
hClose handle
a tmpfile content
renameFile 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 :: Template -> (FilePath -> Handle -> IO a) -> IO a
withTmpFile template a = do
tmpdir <- catchDefaultIO "." getTemporaryDirectory
withTmpFileIn tmpdir template a
{- Runs an action with a tmp file located in the specified directory,
- then removes the file. -}
withTmpFileIn :: FilePath -> Template -> (FilePath -> Handle -> IO a) -> IO a
withTmpFileIn tmpdir template a = bracket create remove use
where
create = openTempFile tmpdir template
remove (name, handle) = do
hClose handle
catchBoolIO (removeFile name >> return True)
use (name, handle) = a name handle
{- 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 :: Template -> (FilePath -> IO a) -> IO a
withTmpDir template a = do
tmpdir <- 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 :: FilePath -> Template -> (FilePath -> IO a) -> IO a
withTmpDirIn tmpdir template = bracket create remove
where
remove d = whenM (doesDirectoryExist d) $
removeDirectoryRecursive d
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
|
