System.Directory.Extra

Extra directory functions. Most of these functions provide cleaned up and generalised versions of getDirectoryContents, see listContents for the differences.

Documentation

module System.Directory

withCurrentDirectory :: FilePath -> IO a -> IO a

Set the current directory, perform an operation, then change back. Remember that the current directory is a global variable, so calling this function multithreaded is almost certain to go wrong. Avoid changing the current directory if you can.

 withTempDir $ \dir -> do writeFile (dir </> "foo.txt") ""; withCurrentDirectory dir $ doesFileExist "foo.txt"

createDirectoryPrivate :: String -> IO ()

Create a directory with permissions so that only the current user can view it. On Windows this function is equivalent to createDirectory.

listContents :: FilePath -> IO [FilePath]

List the files and directories directly within a directory. Each result will be prefixed by the query directory, and the special directories . and .. will be ignored. Intended as a cleaned up version of getDirectoryContents.

 withTempDir $ \dir -> do writeFile (dir </> "test.txt") ""; (== [dir </> "test.txt"]) <$> listContents dir
 let touch = mapM_ $ \x -> createDirectoryIfMissing True (takeDirectory x) >> writeFile x ""
 let listTest op as bs = withTempDir $ \dir -> do touch $ map (dir </>) as; res <- op dir; return $ map (drop (length dir + 1)) res == bs
 listTest listContents ["bar.txt","foo/baz.txt","zoo"] ["bar.txt","foo","zoo"]

listFiles :: FilePath -> IO [FilePath]

Like listContents, but only returns the files in a directory, not other directories. Each file will be prefixed by the query directory.

 listTest listFiles ["bar.txt","foo/baz.txt","zoo"] ["bar.txt","zoo"]

listFilesInside :: (FilePath -> IO Bool) -> FilePath -> IO [FilePath]

Like listFilesRecursive, but with a predicate to decide where to recurse into. Typically directories starting with . would be ignored. The initial argument directory will have the test applied to it.

 listTest (listFilesInside $ return . not . isPrefixOf "." . takeFileName)
     ["bar.txt","foo" </> "baz.txt",".foo" </> "baz2.txt", "zoo"] ["bar.txt","zoo","foo" </> "baz.txt"]
 listTest (listFilesInside $ const $ return False) ["bar.txt"] []

listFilesRecursive :: FilePath -> IO [FilePath]

Like listFiles, but goes recursively through all subdirectories.

 listTest listFilesRecursive ["bar.txt","zoo","foo" </> "baz.txt"] ["bar.txt","zoo","foo" </> "baz.txt"]