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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, hGetLineSafe, nextEvent', tenthSeconds)
+where
+
+import Control.Monad
+import Control.Concurrent
+import Control.Concurrent.STM
+import System.Posix.Types (Fd(..))
+
+import System.Environment
+import System.FilePath
+import System.IO
+
+import Graphics.X11.Xlib (
+ Display(..), XEventPtr, nextEvent, pending, connectionNumber)
+
+#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)
+
+-- | A version of nextEvent that does not block in foreign calls.
+nextEvent' :: Display -> XEventPtr -> IO ()
+nextEvent' d p = do
+ pend <- pending d
+ if pend /= 0
+ then nextEvent d p
+ else do
+ threadWaitRead (Fd fd)
+ nextEvent' d p
+ where
+ fd = connectionNumber d
+
+
+-- | Work around to the Int max bound: since threadDelay takes an Int, it
+-- is not possible to set a thread delay grater than about 45 minutes.
+-- With a little recursion we solve the problem.
+tenthSeconds :: Int -> IO ()
+tenthSeconds s | s >= x = do threadDelay (x * 100000)
+ tenthSeconds (s - x)
+ | otherwise = threadDelay (s * 100000)
+ where x = (maxBound :: Int) `div` 100000