Merge branch 'broadcast-destroy-window-events'

CHANGES.md

@@ -50,6 +50,9 @@
 
   * Document the help command in the help message.
 
+  * `DestroyWindowEvent` is now broadcasted to layouts to let them know
+    window-specific resources can be discarded.
+
 ## 0.15 (September 30, 2018)
 
   * Reimplement `sendMessage` to deal properly with windowset changes made

src/XMonad/Layout.hs

@@ -27,6 +27,7 @@ module XMonad.Layout (
 import XMonad.Core
 
 import Graphics.X11 (Rectangle(..))
+import Graphics.X11.Xlib.Extras ( Event(DestroyWindowEvent) )
 import qualified XMonad.StackSet as W
 import Control.Arrow ((***), second)
 import Control.Monad
@@ -230,6 +231,9 @@ instance (LayoutClass l a, LayoutClass r a) => LayoutClass (Choose l r) a where
     handleMessage c@(Choose d l r) m | Just ReleaseResources <- fromMessage m =
         join $ liftM2 (choose c d) (handle l ReleaseResources) (handle r ReleaseResources)
 
+    handleMessage c@(Choose d l r) m | Just e@DestroyWindowEvent{} <- fromMessage m =
+        join $ liftM2 (choose c d) (handle l e) (handle r e)
+
     handleMessage c@(Choose d l r) m | Just (JumpToLayout desc) <- fromMessage m = do
         ml <- handleMessage l m
         mr <- handleMessage r m

src/XMonad/Main.hs

@@ -315,10 +315,15 @@ handle (MapRequestEvent    {ev_window = w}) = withDisplay $ \dpy -> do
 
 -- window destroyed, unmanage it
 -- window gone,      unmanage it
-handle (DestroyWindowEvent {ev_window = w}) = whenX (isClient w) $ do
+-- broadcast to layouts
+handle e@(DestroyWindowEvent {ev_window = w}) = do
+  whenX (isClient w) $ do
     unmanage w
     modify (\s -> s { mapped       = S.delete w (mapped s)
                     , waitingUnmap = M.delete w (waitingUnmap s)})
+  -- the window is already unmanged, but we broadcast the event to all layouts
+  -- to trigger garbage-collection in case they hold window-specific resources
+  broadcastMessage e
 
 -- We track expected unmap events in waitingUnmap.  We ignore this event unless
 -- it is synthetic or we are not expecting an unmap notification from a window.