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|
-----------------------------------------------------------------------------
-- |
-- Module : Xmobar.Commands
-- Copyright : (c) Andrea Rossato
-- License : BSD-style (see LICENSE)
--
-- Maintainer : Andrea Rossato <andrea.rossato@unibz.it>
-- Stability : unstable
-- Portability : unportable
--
-- The 'Exec' class and the 'Command' data type.
--
-- The 'Exec' class rappresents the executable types, whose constructors may
-- appear in the 'Config.commands' field of the 'Config.Config' data type.
--
-- The 'Command' data type is for OS commands to be run by Xmobar
--
-----------------------------------------------------------------------------
module Commands where
import Control.Concurrent
import Data.Char
import System.Process
import System.Exit
import System.IO (hClose, hGetLine)
class Show e => Exec e where
alias :: e -> String
alias e = takeWhile (not . isSpace) $ show e
rate :: e -> Int
rate _ = 10
run :: e -> IO String
run _ = return ""
start :: e -> (String -> IO ()) -> IO ()
start e cb = go
where go = do
run e >>= cb
tenthSeconds (rate e) >> go
data Command = Com Program Args Alias Rate
deriving (Show,Read,Eq)
type Args = [String]
type Program = String
type Alias = String
type Rate = Int
instance Exec Command where
alias (Com p _ a _)
| p /= "" = if a == "" then p else a
| otherwise = ""
start (Com prog args _ r) cb = do go
where go = do
(i,o,e,p) <- runInteractiveCommand (prog ++ concat (map (' ':) args))
exit <- waitForProcess p
let closeHandles = do
hClose o
hClose i
hClose e
case exit of
ExitSuccess -> do
str <- hGetLine o
closeHandles
cb str
_ -> do closeHandles
cb $ "Could not execute command " ++ prog
tenthSeconds r >> go
-- | Work arount 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 y
tenthSeconds (x - s)
| otherwise = threadDelay (s * 100000)
where y = (maxBound :: Int)
x = y `div` 100000
|
