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|
------------------------------------------------------------------------------
-- |
-- Module: Xmobar.App.CommandThreads
-- Copyright: (c) 2022 Jose Antonio Ortega Ruiz
-- License: BSD3-style (see LICENSE)
--
-- Maintainer: jao@gnu.org
-- Stability: unstable
-- Portability: unportable
-- Created: Fri Jan 28, 2022 03:20
--
--
-- Running a thread for each defined Command
--
------------------------------------------------------------------------------
module Xmobar.App.CommandThreads ( startCommand
, newRefreshLock
, refreshLock
, refreshLockT) where
import Control.Concurrent.STM
import Control.Concurrent.Async (Async, async)
import Control.Exception (bracket_)
import Xmobar.System.Signal (SignalType)
import Xmobar.Run.Runnable (Runnable)
import Xmobar.Run.Exec (start, trigger, alias)
newRefreshLock :: IO (TMVar ())
newRefreshLock = newTMVarIO ()
refreshLock :: TMVar () -> IO a -> IO a
refreshLock var = bracket_ lock unlock
where
lock = atomically $ takeTMVar var
unlock = atomically $ putTMVar var ()
refreshLockT :: TMVar () -> STM a -> STM a
refreshLockT var action = do
takeTMVar var
r <- action
putTMVar var ()
return r
-- | Runs a command as an independent thread and returns its Async handles
-- and the TVar the command will be writing to.
startCommand :: TMVar SignalType
-> (Runnable,String,String)
-> IO ([Async ()], TVar String)
startCommand sig (com,s,ss)
| alias com == "" = do var <- newTVarIO is
atomically $ writeTVar var (s ++ ss)
return ([], var)
| otherwise = do var <- newTVarIO is
let cb str = atomically $ writeTVar var (s ++ str ++ ss)
a1 <- async $ start com cb
a2 <- async $ trigger com $ maybe (return ())
(atomically . putTMVar sig)
return ([a1, a2], var)
where is = s ++ "Updating..." ++ ss
|