Xmobar.App.CommandThreads

1 files changed, 61 insertions, 0 deletions

diff --git a/src/Xmobar/App/CommandThreads.hs b/src/Xmobar/App/CommandThreads.hs
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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