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