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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 Xmobar.Commands
+ ( Command (..)
+ , Exec (..)
+ , tenthSeconds
+ ) where
+
+import Prelude
+import Control.Concurrent
+import Control.Exception (handle, SomeException(..))
+import Data.Char
+import System.Process
+import System.Exit
+import System.IO (hClose)
+
+import Xmobar.Signal
+import Xmobar.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 = run e >>= cb >> tenthSeconds (rate e) >> go
+ trigger :: e -> (Maybe SignalType -> IO ()) -> IO ()
+ trigger _ sh = sh Nothing
+
+data Command = Com Program Args Alias Rate
+ | ComX Program Args String Alias Rate
+ deriving (Show,Read,Eq)
+
+type Args = [String]
+type Program = String
+type Alias = String
+type Rate = Int
+
+instance Exec Command where
+ alias (ComX p _ _ a _) =
+ if p /= "" then (if a == "" then p else a) else ""
+ alias (Com p a al r) = alias (ComX p a "" al r)
+ start (Com p as al r) cb =
+ start (ComX p as ("Could not execute command " ++ p) al r) cb
+ start (ComX prog args msg _ r) cb = if r > 0 then go else exec
+ where go = exec >> tenthSeconds r >> go
+ exec = do
+ (i,o,e,p) <- runInteractiveProcess prog args Nothing Nothing
+ exit <- waitForProcess p
+ let closeHandles = hClose o >> hClose i >> hClose e
+ getL = handle (\(SomeException _) -> return "")
+ (hGetLineSafe o)
+ case exit of
+ ExitSuccess -> do str <- getL
+ closeHandles
+ cb str
+ _ -> closeHandles >> cb msg
+
+
+-- | 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