Change core enter/leave semantics for multiple pointers.

Send EnterNotify when first device enters the window, LeaveNotify when the
last device leaves the window. Additional devices will not cause additional
Enter/LeaveNotifies.

dix/events.c

@@ -2270,7 +2270,10 @@ DefineInitialRootWindow(WindowPtr win)
     while (pDev)
     {
         if (DevHasCursor(pDev))
+        {
             InitializeSprite(pDev, win);
+            win->devPrivates[EnterLeavePrivatesIndex].val++;
+        }
         pDev = pDev->next;
     }
 }
@@ -3447,6 +3450,7 @@ EnterLeaveEvent(
     GrabPtr	        grab = mouse->coreGrab.grab;
     GrabPtr	        devgrab = mouse->deviceGrab.grab;
     Mask		mask;
+    long*               inWindow; /* no of sprites inside pWin */
 
     deviceEnterNotify   *devEnterLeave;
     int                 mskidx;
@@ -3492,14 +3496,23 @@ EnterLeaveEvent(
              IsParent(focus, pWin)))
         event.u.enterLeave.flags |= ELFlagFocus;
 
+    inWindow = &pWin->devPrivates[EnterLeavePrivatesIndex].val;
+
+    (type == EnterNotify) ? (*inWindow)++ : (*inWindow)--;
+
     if (mask & filters[type])
     {
-	if (grab)
-	    (void)TryClientEvents(rClient(grab), &event, 1, mask,
-				  filters[type], grab);
-	else
-	    (void)DeliverEventsToWindow(pDev, pWin, &event, 1, filters[type],
-					NullGrab, 0);
+        /* only send core events for the first device to enter and the last
+           one to leave */
+        if ((*inWindow) == (LeaveNotify - type))
+        {
+            if (grab)
+                (void)TryClientEvents(rClient(grab), &event, 1, mask,
+                                      filters[type], grab);
+            else
+                (void)DeliverEventsToWindow(pDev, pWin, &event, 1, filters[type],
+                                            NullGrab, 0);
+        }
     }
 
     devEnterLeave = (deviceEnterNotify*)&event;

dix/main.c

@@ -391,6 +391,8 @@ main(int argc, char *argv[], char *envp[])
 		FatalError("failed to create scratch GCs");
 	    if (!CreateDefaultStipple(i))
 		FatalError("failed to create default stipple");
+            if (!InitWindowPrivates(pScreen))
+                FatalError("Failed to init window privates.");
 	    if (!CreateRootWindow(pScreen))
 		FatalError("failed to create root window");
 	}

dix/window.c

@@ -155,6 +155,8 @@ _X_EXPORT int screenIsSaved = SCREEN_SAVER_OFF;
 
 _X_EXPORT ScreenSaverStuffRec savedScreenInfo[MAXSCREENS];
 
+_X_EXPORT int EnterLeavePrivatesIndex = -1;
+
 #if 0
 extern void DeleteWindowFromAnyEvents();
 extern Mask EventMaskForClient();
@@ -3969,6 +3971,22 @@ WindowParentHasDeviceCursor(WindowPtr pWin,
     return FALSE;
 }
 
+/**
+ * Initialize some mandatory devPrivates for windows. 
+ *
+ * At the moment, this includes only the enter/leave semaphore.
+ *
+ * Returns TRUE on success.
+ */
+_X_EXPORT Bool
+InitWindowPrivates(ScreenPtr screen)
+{
+    if (EnterLeavePrivatesIndex == -1)
+        EnterLeavePrivatesIndex = AllocateWindowPrivateIndex();
+
+    return AllocateWindowPrivate(screen, EnterLeavePrivatesIndex, 0);
+}
+
 #ifndef NOLOGOHACK
 static void
 DrawLogo(WindowPtr pWin)

include/window.h

@@ -268,4 +268,6 @@ extern void DisableMapUnmapEvents(
 extern void EnableMapUnmapEvents(
     WindowPtr /* pWin */ );
 
+Bool InitWindowPrivates(
+    ScreenPtr /* screen */);
 #endif /* WINDOW_H */

include/windowstr.h

@@ -216,6 +216,7 @@ typedef struct _ScreenSaverStuff {
 
 extern int screenIsSaved;
 extern ScreenSaverStuffRec savedScreenInfo[MAXSCREENS];
+extern int EnterLeavePrivatesIndex;
 
 /*
  * this is the configuration parameter "NO_BACK_SAVE"