extra-1.4.2: Extra functions I use.

Safe Haskell | Safe
Language | Haskell2010

System.Directory.Extra

Description

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

Synopsis

- module System.Directory
- withCurrentDirectory :: FilePath -> IO a -> IO a
- createDirectoryPrivate :: String -> IO ()
- listContents :: FilePath -> IO [FilePath]
- listFiles :: FilePath -> IO [FilePath]
- listFilesInside :: (FilePath -> IO Bool) -> FilePath -> IO [FilePath]
- listFilesRecursive :: FilePath -> IO [FilePath]

# 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"]