Avoiding X server leaks with XftColor cache

This patch is a first complete solution to the long-standing memory
leak (on the X server side) caused by repeteadly asking the server to
allocate XftColor instances.  Despite the fact that we were freeing
them, the server didn't seem to care... this was also happening for
non-Xft Colors, and solved in the same way we'd done here, i.e., by
caching XftColor instances.

And additional complication has been that Graphics.X11.Xft doesn't
export any function to create and retain an XftColor, nor the
necessary datatype constructors to write a compatible version outside
the module (there's no way to construct an XftColor instance to pass
to the other functions in the library).  So, i've created my own lite
version of the whole module, until the day it supports XftColor
creation.

1 files changed, 18 insertions, 24 deletions

diff --git a/src/XUtil.hsc b/src/XUtil.hsc
index 7683387..21dcf3e 100644
--- a/src/XUtil.hsc
+++ b/src/XUtil.hsc
@@ -2,8 +2,8 @@
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  XUtil
--- Copyright   :  (C) 2007 Andrea Rossato
---                (C) 2011, 2012 Jose Antonio Ortega Ruiz
+-- Copyright   :  (C) 2011, 2012 Jose Antonio Ortega Ruiz
+--                (C) 2007 Andrea Rossato
 -- License     :  BSD3
 --
 -- Maintainer  :  jao@gnu.org
@@ -48,11 +48,11 @@ import qualified System.IO as UTF8 (readFile,hGetLine)
 #endif
 #if defined XFT
 import Data.List
-import Graphics.X11.Xft
+import MinXft
 import Graphics.X11.Xrender
 #endif
 
-import ColorCache (withColors)
+import ColorCache
 
 readFileSafe :: FilePath -> IO String
 #if defined XFT || defined UTF8
@@ -72,7 +72,7 @@ hGetLineSafe = hGetLine
 data XFont = Core FontStruct
            | Utf8 FontSet
 #ifdef XFT
-           | Xft  XftFont
+           | Xft  AXftFont
 #endif
 
 -- | When initFont gets a font name that starts with 'xft:' it switchs
@@ -118,11 +118,11 @@ initUtf8Font d s = do
             fallBack = const $ createFontSet d miscFixedFont
 
 #ifdef XFT
-initXftFont :: Display -> String -> IO XftFont
+initXftFont :: Display -> String -> IO AXftFont
 initXftFont d s = do
   setupLocale
-  f <- xftFontOpen d (defaultScreenOfDisplay d) (drop 4 s)
-  addFinalizer f (xftFontClose d f)
+  f <- openAXftFont d (defaultScreenOfDisplay d) (drop 4 s)
+  addFinalizer f (closeAXftFont d f)
   return f
 #endif
 
@@ -131,7 +131,7 @@ textWidth _   (Utf8 fs) s = return $ fi $ wcTextEscapement fs s
 textWidth _   (Core fs) s = return $ fi $ Xlib.textWidth fs s
 #ifdef XFT
 textWidth dpy (Xft xftdraw) s = do
-    gi <- xftTextExtents dpy xftdraw s
+    gi <- xftTxtExtents dpy xftdraw s
     return $ xglyphinfo_xOff gi
 #endif
 
@@ -146,8 +146,8 @@ textExtents (Utf8 fs) s = do
   return (ascent, descent)
 #ifdef XFT
 textExtents (Xft xftfont) _ = do
-  ascent  <- fi `fmap` xftfont_ascent  xftfont
-  descent <- fi `fmap` xftfont_descent xftfont
+  ascent  <- fi `fmap` xft_ascent  xftfont
+  descent <- fi `fmap` xft_descent xftfont
   return (ascent, descent)
 #endif
 
@@ -168,20 +168,14 @@ printString d p (Utf8 fs) gc fc bc x y s =
 
 #ifdef XFT
 printString dpy drw fs@(Xft font) _ fc bc x y s = do
-  let screen   = defaultScreenOfDisplay dpy
-      colormap = defaultColormapOfScreen screen
-      visual   = defaultVisualOfScreen screen
   (a,d)  <- textExtents fs s
-  gi <- xftTextExtents dpy font s
-  withXftDraw dpy drw visual colormap $ \draw ->
-    (withXftColorName dpy visual colormap bc $ \color ->
-      xftDrawRect draw color (x + 1 - fi (xglyphinfo_x gi))
-                             (y - (a + d) + 1)
-                             (xglyphinfo_xOff gi)
-                             (a + d)
-                             ) >>
-    (withXftColorName dpy visual colormap fc $ \color ->
-        xftDrawString draw color font x (y - 2) s)
+  gi <- xftTxtExtents dpy font s
+  withDrawingColors dpy drw fc bc $ \draw -> \fc' -> \bc' ->
+    (drawXftRect draw bc' (x + 1 - fi (xglyphinfo_x gi))
+                          (y - (a + d) + 1)
+                          (xglyphinfo_xOff gi)
+                          (a + d)) >>
+    (drawXftString draw fc' font x (y - 2) s)
 #endif