summaryrefslogtreecommitdiffhomepage
path: root/src/Xmobar/System/Utils.hs
blob: d4bdd78e953ceaeb467199e5e9d34448548595e2 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
{-# LANGUAGE CPP #-}

------------------------------------------------------------------------------
-- |
-- Module: Utils
-- Copyright: (c) 2010, 2018 Jose Antonio Ortega Ruiz
-- License: BSD3-style (see LICENSE)
--
-- Maintainer: Jose A Ortega Ruiz <jao@gnu.org>
-- Stability: unstable
-- Portability: unportable
-- Created: Sat Dec 11, 2010 20:55
--
--
-- Miscellaneous utility functions
--
------------------------------------------------------------------------------


module Xmobar.System.Utils (expandHome, changeLoop, hGetLineSafe)
where

import Control.Monad
import Control.Concurrent.STM

import System.Environment
import System.FilePath
import System.IO

#if defined XFT || defined UTF8
import qualified System.IO as S (hGetLine)
#endif

hGetLineSafe :: Handle -> IO String
#if defined XFT || defined UTF8
hGetLineSafe = S.hGetLine
#else
hGetLineSafe = hGetLine
#endif


expandHome :: FilePath -> IO FilePath
expandHome ('~':'/':path) = fmap (</> path) (getEnv "HOME")
expandHome p = return p

changeLoop :: Eq a => STM a -> (a -> IO ()) -> IO ()
changeLoop s f = atomically s >>= go
 where
    go old = do
        f old
        go =<< atomically (do
            new <- s
            guard (new /= old)
            return new)