104 lines
3.3 KiB
Haskell
104 lines
3.3 KiB
Haskell
{-# LANGUAGE GeneralizedNewtypeDeriving #-}
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module WorkspaceMon (M.fromList, runWorkspaceMon) where
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import SendXMsg
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import qualified Data.Map as M
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import Control.Concurrent
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import Control.Monad
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import Control.Monad.Reader
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import Graphics.X11.Types
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import Graphics.X11.Xlib.Atom
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import Graphics.X11.Xlib.Display
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import Graphics.X11.Xlib.Event
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import Graphics.X11.Xlib.Extras
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import Graphics.X11.Xlib.Misc
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import Graphics.X11.Xlib.Types
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import System.Directory
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import System.Process (Pid)
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-- TOOD it would be really nice if the manner we used to match windows was
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-- the same as that in XMonad itself (eg with Query types)
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type MatchTags = M.Map String String
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type WatchedPIDs = MVar [Pid]
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data WConf = WConf
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{ display :: Display
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, matchTags :: MatchTags
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}
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newtype W a = W (ReaderT WConf IO a)
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deriving (Functor, Monad, MonadIO, MonadReader WConf)
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instance Applicative W where
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pure = return
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(<*>) = ap
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runW :: WConf -> W a -> IO a
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runW c (W a) = runReaderT a c
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io :: MonadIO m => IO a -> m a
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io = liftIO
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runWorkspaceMon :: MatchTags -> IO ()
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runWorkspaceMon mts = do
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dpy <- openDisplay ""
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root <- rootWindow dpy $ defaultScreen dpy
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curPIDs <- newMVar [] -- TODO this is ugly, use a mutable state monad
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-- listen only for substructure change events (which includes MapNotify)
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allocaSetWindowAttributes $ \a -> do
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set_event_mask a substructureNotifyMask
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changeWindowAttributes dpy root cWEventMask a
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let c = WConf { display = dpy, matchTags = mts }
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_ <- allocaXEvent $ \e ->
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runW c $ forever $ handle curPIDs =<< io (nextEvent dpy e >> getEvent e)
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return ()
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handle :: WatchedPIDs -> Event -> W ()
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-- | assume this fires at least once when a new window is created (also could
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-- use CreateNotify but that is really noisy)
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handle curPIDs MapNotifyEvent { ev_window = w } = do
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dpy <- asks display
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hint <- io $ getClassHint dpy w
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mts <- asks matchTags
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let tag = M.lookup (resClass hint) mts
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io $ forM_ tag $ \t -> do
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a <- internAtom dpy "_NET_WM_PID" False
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pid <- getWindowProperty32 dpy a w
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case pid of
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-- ASSUMPTION windows will only have one PID at one time
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Just [p] -> let p' = fromIntegral p
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in void $ forkIO $ withUniquePid curPIDs p' $ waitAndKill t p'
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_ -> return ()
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handle _ _ = return ()
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waitAndKill :: String -> Pid -> IO ()
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waitAndKill tag pid = waitUntilExit pidDir
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where
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pidDir = "/proc/" ++ show pid
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waitUntilExit d = do
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-- TODO this will not work if the process is a zombie (maybe I care...)
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-- ASSUMPTION on linux PIDs will always increase until they overflow, in
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-- which case they will start to recycle. Barring any fork bombs, this
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-- code should work because we can reasonably expect that no processes
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-- will spawn with the same PID within the delay limit
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res <- doesDirectoryExist d
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if res then threadDelay 100000 >> waitUntilExit d
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else sendXMsg Workspace tag
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withUniquePid :: WatchedPIDs -> Pid -> IO () -> IO ()
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withUniquePid curPIDs pid f = do
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pids <- readMVar curPIDs
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unless (pid `elem` pids) $ do
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modifyMVar_ curPIDs (return . (pid:))
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f
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modifyMVar_ curPIDs (return . filter (/=pid))
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