git-annex/Utility/Directory.hs
2012-06-06 13:13:13 -04:00

107 lines
3.2 KiB
Haskell

{- directory manipulation
-
- Copyright 2011 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Utility.Directory where
import System.IO.Error
import System.Posix.Files
import System.Directory
import Control.Exception (throw)
import Control.Monad
import Control.Monad.IfElse
import System.FilePath
import Control.Applicative
import Control.Exception (bracket_)
import System.Posix.Directory
import System.IO.Unsafe (unsafeInterleaveIO)
import Utility.SafeCommand
import Utility.TempFile
import Utility.Exception
import Utility.Monad
import Utility.Path
dirCruft :: FilePath -> Bool
dirCruft "." = True
dirCruft ".." = True
dirCruft _ = False
{- Lists the contents of a directory.
- Unlike getDirectoryContents, paths are not relative to the directory. -}
dirContents :: FilePath -> IO [FilePath]
dirContents d = map (d </>) . filter (not . dirCruft) <$> getDirectoryContents d
{- Gets contents of directory, and then its subdirectories, recursively,
- and lazily. -}
dirContentsRecursive :: FilePath -> IO [FilePath]
dirContentsRecursive topdir = dirContentsRecursive' topdir [""]
dirContentsRecursive' :: FilePath -> [FilePath] -> IO [FilePath]
dirContentsRecursive' _ [] = return []
dirContentsRecursive' topdir (dir:dirs) = unsafeInterleaveIO $ do
(files, dirs') <- collect [] [] =<< dirContents (topdir </> dir)
files' <- dirContentsRecursive' topdir (dirs' ++ dirs)
return (files ++ files')
where
collect files dirs' [] = return (reverse files, reverse dirs')
collect files dirs' (entry:entries)
| dirCruft entry = collect files dirs' entries
| otherwise = do
let dirEntry = dir </> entry
ifM (doesDirectoryExist $ topdir </> dirEntry)
( collect files (dirEntry:dirs') entries
, collect (dirEntry:files) dirs' entries
)
{- Moves one filename to another.
- First tries a rename, but falls back to moving across devices if needed. -}
moveFile :: FilePath -> FilePath -> IO ()
moveFile src dest = tryIO (rename src dest) >>= onrename
where
onrename (Right _) = noop
onrename (Left e)
| isPermissionError e = rethrow
| isDoesNotExistError e = rethrow
| otherwise = do
-- copyFile is likely not as optimised as
-- the mv command, so we'll use the latter.
-- But, mv will move into a directory if
-- dest is one, which is not desired.
whenM (isdir dest) rethrow
viaTmp mv dest undefined
where
rethrow = throw e
mv tmp _ = do
ok <- boolSystem "mv" [Param "-f",
Param src, Param tmp]
unless ok $ do
-- delete any partial
_ <- tryIO $ removeFile tmp
rethrow
isdir f = do
r <- tryIO $ getFileStatus f
case r of
(Left _) -> return False
(Right s) -> return $ isDirectory s
{- Removes a file, which may or may not exist.
-
- Note that an exception is thrown if the file exists but
- cannot be removed. -}
nukeFile :: FilePath -> IO ()
nukeFile file = whenM (doesFileExist file) $ removeFile file
{- Runs an action in another directory. -}
bracketCd :: FilePath -> IO a -> IO a
bracketCd dir a = go =<< getCurrentDirectory
where
go cwd
| dirContains dir cwd = a
| otherwise = bracket_
(changeWorkingDirectory dir)
(changeWorkingDirectory cwd)
a