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+-----------------------------------------------------------------------------
+-- |
+-- Module : Xmobar.Commands
+-- Copyright : (c) Andrea Rossato
+-- License : BSD-style (see LICENSE)
+--
+-- Maintainer : Jose A. Ortega Ruiz <jao@gnu.org>
+-- 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
+ ( Command (..)
+ , Exec (..)
+ , tenthSeconds
+ ) where
+
+import Prelude hiding (catch)
+import Control.Concurrent
+import Control.Exception
+import Data.Char
+import System.Process
+import System.Exit
+import System.IO (hClose)
+import XUtil
+
+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 = if r > 0 then go else exec
+ where go = exec >> tenthSeconds r >> go
+ exec = do
+ (i,o,e,p) <- runInteractiveCommand (unwords (prog:args))
+ exit <- waitForProcess p
+ let closeHandles = hClose o >> hClose i >> hClose e
+ case exit of
+ ExitSuccess -> do
+ str <- catch (hGetLineSafe o)
+ (\(SomeException _) -> return "")
+ closeHandles
+ cb str
+ _ -> do closeHandles
+ cb $ "Could not execute command " ++ prog
+
+
+-- | 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 y
+ tenthSeconds (x - s)
+ | otherwise = threadDelay (s * 100000)
+ where y = maxBound :: Int
+ x = y `div` 100000