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{-# 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.Utils (expandHome, changeLoop, safeHead, 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)
safeHead :: [a] -> Maybe a
safeHead [] = Nothing
safeHead (x:_) = Just x
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