XMonad/Hooks/DebugKeyEvents - debug helper to see what keys xmonad sees

XMonad/Hooks/DebugKeyEvents.hs

@@ -0,0 +1,107 @@
+-----------------------------------------------------------------------------
+-- |
+-- Module       : XMonad.Hooks.DebugKeyEvents
+-- Copyright    : (c) 2011 Brandon S Allbery <allbery.b@gmail.com>
+-- License      : BSD
+--
+-- Maintainer   : Brandon S Allbery <allbery.b@gmail.com>
+-- Stability    : unstable
+-- Portability  : unportable
+--
+-- A debugging module to track key events, useful when you can't tell whether
+-- xmonad is processing some or all key events.
+-----------------------------------------------------------------------------
+
+module XMonad.Hooks.DebugKeyEvents (-- * Usage
+                                    -- $usage
+                                    debugKeyEvents
+                                   ) where
+
+import           XMonad.Core
+import           XMonad.Operations               (cleanMask)
+
+import           Graphics.X11.Xlib
+import           Graphics.X11.Xlib.Extras
+
+import           Control.Monad.State             (gets)
+import           Data.Bits
+import           Data.List                       (intercalate)
+import           Data.Monoid
+import           Numeric                         (showHex)
+import           System.IO                       (hPutStrLn
+                                                 ,stderr)
+
+-- $usage
+-- Add this to your handleEventHook to print received key events to the
+-- log (the console if you use @startx@/@xinit@, otherwise usually
+-- @~/.xsession-errors@).
+--
+-- >      , handleEventHook = debugKeyEvents
+--
+-- If you already have a handleEventHook then you should append it:
+--
+-- >      , handleEventHook = ... <+> debugKeyEvents
+--
+-- Logged key events look like:
+--
+-- @keycode 53 sym 120 (0x78, "x") mask 0x0 () clean 0x0 ()@
+-- 
+-- The @mask@ and @clean@ indicate the modifiers pressed along with
+-- the key; @mask@ is raw, and @clean@ is what @xmonad@ sees after
+-- sanitizing it (removing @numberLockMask@, etc.)
+--
+-- For more detailed instructions on editing the logHook see:
+--
+-- "XMonad.Doc.Extending#The_log_hook_and_external_status_bars"
+
+-- | Print key events to stderr for debugging
+debugKeyEvents :: Event -> X All
+debugKeyEvents (KeyEvent {ev_event_type = t, ev_state = m, ev_keycode = code})
+  | t == keyPress =
+      withDisplay $ \dpy -> do
+        sym <- io $ keycodeToKeysym dpy code 0
+        msk <- cleanMask m
+        nl <- gets numberlockMask
+        io $ hPutStrLn stderr $ intercalate " " ["keycode"
+                                                ,show code
+                                                ,"sym"
+                                                ,show sym
+                                                ," ("
+                                                ,hex sym
+                                                ," \""
+                                                ,keysymToString sym
+                                                ,"\") mask"
+                                                ,hex m
+                                                ,"(" ++ vmask nl m ++ ")"
+                                                ,"clean"
+                                                ,hex msk
+                                                ,"(" ++ vmask nl msk ++ ")"
+                                                ]
+        return (All True)
+debugKeyEvents _ = return (All True)
+
+-- | Convenient showHex variant
+hex :: Integral n => n -> String
+hex v = "0x" ++ showHex v ""
+
+-- | Convert a modifier mask into a useful string
+vmask                 :: KeyMask -> KeyMask -> String
+vmask numLockMask msk =  intercalate " " $
+                         reverse $
+                         fst $
+                         foldr vmask' ([],msk) masks
+    where
+      masks = map (\m -> (m,show m)) [0..toEnum (bitSize msk - 1)] ++
+              [(numLockMask,"num"  )
+              ,(   lockMask,"lock" )
+              ,(controlMask,"ctrl" )
+              ,(  shiftMask,"shift")
+              ,(   mod5Mask,"mod5" )
+              ,(   mod4Mask,"mod4" )
+              ,(   mod3Mask,"mod3" )
+              ,(   mod2Mask,"mod2" )
+              ,(   mod1Mask,"mod1" )
+              ]
+      vmask'   _   a@( _,0)                = a
+      vmask' (m,s)   (ss,v) | v .&. m == m = (s:ss,v .&. complement m)
+      vmask'   _        r                  = r

xmonad-contrib.cabal

@@ -137,6 +137,7 @@ library
                         XMonad.Config.Sjanssen
                         XMonad.Config.Xfce
                         XMonad.Hooks.CurrentWorkspaceOnTop
+                        XMonad.Hooks.DebugKeyEvents
                         XMonad.Hooks.DynamicHooks
                         XMonad.Hooks.DynamicLog
                         XMonad.Hooks.EwmhDesktops