xmonad-config/lib/WorkspaceMon.hs

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2020-03-25 12:24:40 -04:00
module WorkspaceMon (runWorkspaceMon) where
import Control.Concurrent
import Control.Monad
import Graphics.X11.Types
import Graphics.X11.Xlib.Atom
import Graphics.X11.Xlib.Display
import Graphics.X11.Xlib.Event
import Graphics.X11.Xlib.Extras
import Graphics.X11.Xlib.Misc
import Graphics.X11.Xlib.Types
import System.Directory
import System.Process (Pid)
runWorkspaceMon :: IO ()
runWorkspaceMon = do
dpy <- openDisplay ""
root <- rootWindow dpy $ defaultScreen dpy
-- listen only for substructure change events (which includes MapNotify)
allocaSetWindowAttributes $ \a -> do
set_event_mask a substructureNotifyMask
changeWindowAttributes dpy root cWEventMask a
_ <- allocaXEvent $ \e ->
forever $ handle dpy =<< (nextEvent dpy e >> getEvent e)
return ()
handle :: Display -> Event -> IO ()
-- | assume this fires at least once when a new window is created (also could
-- use CreateNotify but that is really noisy)
handle dpy MapNotifyEvent { ev_window = w } = do
hint <- getClassHint dpy w
-- this will need to eventually accept a conditional argument that
-- we can change upon initialization
when (resName hint == "gimp") $ do
a <- internAtom dpy "_NET_WM_PID" False
pid <- getWindowProperty32 dpy a w
case pid of
-- ASSUMPTION windows will only have one PID at one time
Just [p] -> waitAndKill $ fromIntegral p
_ -> return ()
handle _ _ = return ()
waitAndKill :: Pid -> IO ()
waitAndKill pid = waitUntilExit pidDir
where
pidDir = "/proc/" ++ show pid
waitUntilExit d = do
-- TODO this will not work if the process is a zombie (maybe I care...)
-- ASSUMPTION on linux PIDs will always increase until they overflow, in
-- which case they will start to recycle. Barring any fork bombs, this
-- code should work because we can reasonably expect that no processes
-- will spawn with the same PID within the delay limit
res <- doesDirectoryExist d
when res $ do
threadDelay 100000
waitUntilExit d