xfixes: backup the DisplayCursor/CloseScreen proc before restoring it (#23034)

The screen's DisplayCursor func is wrapped as
AnimCurDisplayCursor -> CursorDisplayCursor -> miPointerDisplayCursor.

Calling CursorDisplayCursor while an animated cursor was currently displayed
would remove AnimCurDisplayCursor from the wrap stack. Thus, the next call
to ChangeToCursor wouldn't update the animated cursor state. The block
handler for animated cursors would then continuously overwrite the actual
cursor, leaving an animated cursor everywhere on the screen.

X.Org Bug 23034 <http://bugs.freedesktop.org/show_bug.cgi?id=23034>

1 files changed, 9 insertions, 5 deletions

diff --git a/xfixes/cursor.c b/xfixes/cursor.c
index 45891bbe1..acc703a42 100644
--- a/xfixes/cursor.c
+++ b/xfixes/cursor.c
@@ -131,7 +131,7 @@ typedef struct _CursorScreen {
 #define GetCursorScreenIfSet(s) GetCursorScreen(s)
 #define SetCursorScreen(s,p) dixSetPrivate(&(s)->devPrivates, CursorScreenPrivateKey, p)
 #define Wrap(as,s,elt,func)	(((as)->elt = (s)->elt), (s)->elt = func)
-#define Unwrap(as,s,elt)	((s)->elt = (as)->elt)
+#define Unwrap(as,s,elt,backup)	(((backup) = (s)->elt), (s)->elt = (as)->elt)
 
 /* The cursor doesn't show up until the first XDefineCursor() */
 static Bool CursorVisible = FALSE;
@@ -145,8 +145,9 @@ CursorDisplayCursor (DeviceIntPtr pDev,
 {
     CursorScreenPtr	cs = GetCursorScreen(pScreen);
     Bool		ret;
+    DisplayCursorProcPtr backupProc;
 
-    Unwrap (cs, pScreen, DisplayCursor);
+    Unwrap (cs, pScreen, DisplayCursor, backupProc);
 
     /*
      * Have to check ConnectionInfo to distinguish client requests from
@@ -184,7 +185,8 @@ CursorDisplayCursor (DeviceIntPtr pDev,
 	    }
 	}
     }
-    Wrap (cs, pScreen, DisplayCursor, CursorDisplayCursor);
+    Wrap (cs, pScreen, DisplayCursor, backupProc);
+
     return ret;
 }
 
@@ -193,9 +195,11 @@ CursorCloseScreen (int index, ScreenPtr pScreen)
 {
     CursorScreenPtr	cs = GetCursorScreen (pScreen);
     Bool		ret;
+    CloseScreenProcPtr	close_proc;
+    DisplayCursorProcPtr display_proc;
 
-    Unwrap (cs, pScreen, CloseScreen);
-    Unwrap (cs, pScreen, DisplayCursor);
+    Unwrap (cs, pScreen, CloseScreen, close_proc);
+    Unwrap (cs, pScreen, DisplayCursor, display_proc);
     deleteCursorHideCountsForScreen(pScreen);
     ret = (*pScreen->CloseScreen) (index, pScreen);
     xfree (cs);