dix: only show the cursor if a window defines one (#58398)

e02f864f "Suppress cursor display until the first XDefineCursor() request"
disabled cursor display a priori unless -retro is given.

On a plain server, caling XFixesHideCursor() and XFixesShowCursor() would
show the default root cursor, despite no client actually defining a cursor.

Change the logic, disable CursorVisible by default and only enable it from
the window's CWCursor logic. If no window ever defines a cursor, said cursor
stays invisible.

X.Org Bug 58398 <http://bugs.freedesktop.org/show_bug.cgi?id=58398>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Tested-by: Bastien Nocera <hadess@hadess.net>
Reviewed-by: Daniel Martin <consume.noise@gmail.com>

dix/window.c

@@ -1431,6 +1431,8 @@ ChangeWindowAttributes(WindowPtr pWin, Mask vmask, XID *vlist, ClientPtr client)
                     }
                 }
 
+                CursorVisible = TRUE;
+
                 if (pWin->realized)
                     WindowHasNewCursor(pWin);
 
@@ -3430,6 +3432,8 @@ ChangeWindowDeviceCursor(WindowPtr pWin, DeviceIntPtr pDev, CursorPtr pCursor)
     }
 
  out:
+    CursorVisible = TRUE;
+
     if (pWin->realized)
         WindowHasNewCursor(pWin);
 

include/input.h

@@ -638,6 +638,11 @@ extern _X_HIDDEN void valuator_set_mode(DeviceIntPtr dev, int axis, int mode);
    xfixes/cursor.c uses it to determine if the cursor is enabled */
 extern Bool EnableCursor;
 
+/* Set to FALSE by default - ChangeWindowAttributes sets it to TRUE on
+ * CWCursor, xfixes/cursor.c uses it to determine if the cursor is enabled
+ */
+extern Bool CursorVisible;
+
 extern _X_EXPORT ValuatorMask *valuator_mask_new(int num_valuators);
 extern _X_EXPORT void valuator_mask_free(ValuatorMask **mask);
 extern _X_EXPORT void valuator_mask_set_range(ValuatorMask *mask,

xfixes/cursor.c

@@ -129,8 +129,7 @@ typedef struct _CursorScreen {
 #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;
-
+Bool CursorVisible = FALSE;
 Bool EnableCursor = TRUE;
 
 static Bool
@@ -142,12 +141,7 @@ CursorDisplayCursor(DeviceIntPtr pDev, ScreenPtr pScreen, CursorPtr pCursor)
 
     Unwrap(cs, pScreen, DisplayCursor, backupProc);
 
-    /*
-     * Have to check ConnectionInfo to distinguish client requests from
-     * initial root window setup.  Not a great way to do it, I admit.
-     */
-    if (ConnectionInfo)
-        CursorVisible = EnableCursor;
+    CursorVisible = CursorVisible && EnableCursor;
 
     if (cs->pCursorHideCounts != NULL || !CursorVisible) {
         ret = (*pScreen->DisplayCursor) (pDev, pScreen, NullCursor);