debug-hooks

Ignore-this: 7f41c93fdd6643c687598d2fe07aad5d
Hooks to print diagnostic information to stderr (usually .xsession-errors)
to help debug complex issues involving the StackSet and received events.

darcs-hash:20120813223821-181ff-63a79101b02b74c351344ae3d2768153a688ec7c.gz

1 files changed, 140 insertions, 0 deletions

diff --git a/XMonad/Util/DebugWindow.hs b/XMonad/Util/DebugWindow.hs
new file mode 100644
index 0000000..413f700
--- /dev/null
+++ b/XMonad/Util/DebugWindow.hs
@@ -0,0 +1,140 @@
+-----------------------------------------------------------------------------
+-- |
+-- Module      :  XMonad.Util.DebugWindow
+-- Copyright   :  (c) Brandon S Allbery KF8NH, 2012
+-- License     :  BSD3-style (see LICENSE)
+--
+-- Maintainer  :  allbery.b@gmail.com
+-- Stability   :  unstable
+-- Portability :  not portable
+--
+-- Module to dump window information for diagnostic/debugging purposes.  See 
+-- "XMonad.Hooks.DebugEvents" and "XMonad.Hooks.DebugStack" for practical uses.
+--
+-----------------------------------------------------------------------------
+
+module XMonad.Util.DebugWindow (debugWindow) where
+
+import           Prelude                  hiding (catch)
+
+import           XMonad
+
+import           Codec.Binary.UTF8.String        (decodeString)
+import           Control.Exception
+import           Control.Monad                   (when)
+import           Data.List                       (unfoldr
+                                                 ,intercalate
+                                                 )
+import           Foreign
+import           Foreign.C.String
+import           Numeric                         (showHex)
+import           System.Exit
+
+-- | Output a window by ID in hex, decimal, its ICCCM resource name and class,
+--   and its title if available.  Also indicate override_redirect with an
+--   exclamation mark, and wrap in brackets if it is unmapped or withdrawn.
+debugWindow   :: Window -> X String
+debugWindow 0 =  return "None"
+debugWindow w =  do
+  let wx = pad 8 '0' $ showHex w ""
+  w' <- withDisplay $ \d -> io (safeGetWindowAttributes d w)
+  case w' of
+    Nothing                                   ->
+      return $ "(deleted window " ++ wx ++ ")"
+    Just (WindowAttributes x y wid ht bw m o) -> do
+      c' <- withDisplay $ \d ->
+            io (getWindowProperty8 d wM_CLASS w)
+      let c = case c' of
+                Nothing -> ""
+                Just c''  -> intercalate "/" $
+                             flip unfoldr (map (toEnum . fromEnum) c'') $
+                             \s -> if null s
+                                     then Nothing
+                                     else let (w'',s'') = break (== '\NUL') s
+                                              s'      = if null s''
+                                                          then s''
+                                                          else tail s''
+                                          in Just (w'',s')
+      t <- catchX' (wrap `fmap` getEWMHTitle  "VISIBLE" w) $
+           catchX' (wrap `fmap` getEWMHTitle  ""        w) $
+           catchX' (wrap `fmap` getICCCMTitle           w) $
+           return ""
+      let (lb,rb) = case () of
+                      () | m == waIsViewable -> ("","")
+                         | otherwise         -> ("[","]")
+          o'      = if o then "!" else ""
+      return $ concat [lb
+                      ,o'
+                      ,"window "
+                      ,wx
+                      ,t
+                      ," ("
+                      ,show wid
+                      ,',':show ht
+                      ,')':if bw == 0 then "" else '+':show bw
+                      ,"@("
+                      ,show x
+                      ,',':show y
+                      ,')':if null c then "" else ' ':c
+                      ,rb
+                      ]
+
+getEWMHTitle       :: String -> Window -> X String
+getEWMHTitle sub w =  do
+  a <- getAtom $ "_NET_WM_" ++ (if null sub then "" else '_':sub) ++ "_NAME"
+  (Just t) <- withDisplay $ \d -> io $ getWindowProperty32 d a w
+  return $ map (toEnum . fromEnum) t
+
+getICCCMTitle   :: Window -> X String
+getICCCMTitle w =  do
+  t@(TextProperty t' _ 8 _) <- withDisplay $ \d -> io $ getTextProperty d w wM_NAME
+  [s] <- catchX' (tryUTF8     t) $
+         catchX' (tryCompound t) $
+         io ((:[]) `fmap` peekCString t')
+  return s
+
+tryUTF8                          :: TextProperty -> X [String]
+tryUTF8 (TextProperty s enc _ _) =  do
+  uTF8_STRING <- getAtom "UTF8_STRING"
+  when (enc == uTF8_STRING) $ error "String is not UTF8_STRING"
+  (map decodeString . splitNul) `fmap` io (peekCString s)
+
+tryCompound                            :: TextProperty -> X [String]
+tryCompound t@(TextProperty _ enc _ _) =  do
+  cOMPOUND_TEXT <- getAtom "COMPOUND_TEXT"
+  when (enc == cOMPOUND_TEXT) $ error "String is not COMPOUND_TEXT"
+  withDisplay $ \d -> io $ wcTextPropertyToTextList d t
+
+splitNul    :: String -> [String]
+splitNul "" =  []
+splitNul s  =  let (s',ss') = break (== '\NUL') s in s' : splitNul ss'
+
+pad       :: Int -> Char -> String -> String
+pad w c s =  replicate (w - length s) c ++ s
+
+-- modified 'catchX' without the print to 'stderr'
+catchX' :: X a -> X a -> X a
+catchX' job errcase = do
+  st <- get
+  c <- ask
+  (a, s') <- io $ runX c st job `catch` \e -> case fromException e of
+    Just x -> throw e `const` (x `asTypeOf` ExitSuccess)
+    _ -> runX c st errcase
+  put s'
+  return a
+
+wrap   :: String -> String
+wrap s =  ' ' : '"' : wrap' s ++ "\""
+  where
+    wrap' (s':ss) | s' == '"'  = '\\' : s' : wrap' ss
+                  | s' == '\\' = '\\' : s' : wrap' ss
+                  | otherwise  =        s' : wrap' ss
+    wrap' ""                   =             ""
+
+-- Graphics.X11.Extras.getWindowAttributes is bugggggggy
+safeGetWindowAttributes     :: Display -> Window -> IO (Maybe WindowAttributes)
+safeGetWindowAttributes d w =  alloca $ \p -> do
+  s <- xGetWindowAttributes d w p
+  case s of
+    0 -> return Nothing
+    _ -> Just `fmap` peek p