[PATCH xserver v2] xwayland: Apply "last pointer window" check only to the pointer device

[Carlos Garnacho]

The checks in xwayland's XYToWindow handler pretty much assumes that the
sprite is managed by the wl_pointer, which is not entirely right, given
1) The Virtual Core Pointer may be controlled from other interfaces, and
2) there may be other SpriteRecs than the VCP's.

This makes XYToWindow calls return a sprite trace with just the root
window if any of those two assumptions are broken, eg. on touch events.

So turn the check upside down, first assume that the default XYToWindow
proc behavior is right, and later cut down the spriteTrace if the
current device happens to be the pointer and is out of focus. We work
our way to the device's lastSlave here so as not to break assumption #1
above.

Signed-off-by: Carlos Garnacho <carlosg at gnome.org>
---
 hw/xwayland/xwayland-input.c | 59 ++++++++++++++++++++++++++++++--------------
 1 file changed, 40 insertions(+), 19 deletions(-)

diff --git a/hw/xwayland/xwayland-input.c b/hw/xwayland/xwayland-input.c
index 32cfb35..029ae04 100644
--- a/hw/xwayland/xwayland-input.c
+++ b/hw/xwayland/xwayland-input.c
@@ -945,44 +945,65 @@ DDXRingBell(int volume, int pitch, int duration)
 {
 }
 
-static WindowPtr
-xwl_xy_to_window(ScreenPtr screen, SpritePtr sprite, int x, int y)
+static Bool
+sprite_check_lost_focus(SpritePtr sprite, WindowPtr window)
 {
-    struct xwl_seat *xwl_seat = NULL;
-    DeviceIntPtr device;
-    WindowPtr ret;
+    DeviceIntPtr device, master;
+    struct xwl_seat *xwl_seat;
 
     for (device = inputInfo.devices; device; device = device->next) {
+        /* Ignore non-wayland devices */
         if (device->deviceProc == xwl_pointer_proc &&
-            device->spriteInfo->sprite == sprite) {
-            xwl_seat = device->public.devicePrivate;
+            device->spriteInfo->sprite == sprite)
             break;
-        }
     }
 
-    if (xwl_seat == NULL) {
-        sprite->spriteTraceGood = 1;
-        return sprite->spriteTrace[0];
-    }
+    if (!device)
+        return FALSE;
+
+    xwl_seat = device->public.devicePrivate;
+
+    master = GetMaster(device, POINTER_OR_FLOAT);
+    if (!master || !master->lastSlave)
+        return FALSE;
 
-    screen->XYToWindow = xwl_seat->xwl_screen->XYToWindow;
+    /* We do want the last active slave, we only check on slave xwayland devices
+     * so we can find out the xwl_seat, but those don't actually own their
+     * sprite, so the match doesn't mean a lot.
+     */
+    if (master->lastSlave == xwl_seat->pointer &&
+        xwl_seat->focus_window == NULL &&
+        xwl_seat->last_xwindow == window)
+        return TRUE;
+
+    xwl_seat->last_xwindow = window;
+    return FALSE;
+}
+
+static WindowPtr
+xwl_xy_to_window(ScreenPtr screen, SpritePtr sprite, int x, int y)
+{
+    struct xwl_screen *xwl_screen;
+    WindowPtr ret;
+
+    xwl_screen = xwl_screen_get(screen);
+
+    screen->XYToWindow = xwl_screen->XYToWindow;
     ret = screen->XYToWindow(screen, sprite, x, y);
-    xwl_seat->xwl_screen->XYToWindow = screen->XYToWindow;
+    xwl_screen->XYToWindow = screen->XYToWindow;
     screen->XYToWindow = xwl_xy_to_window;
 
-    /* If the pointer has left the Wayland surface but the DIX still
-     * finds the pointer within the previous X11 window, it means that
+    /* If the device controlling the sprite has left the Wayland surface but
+     * the DIX still finds the pointer within the X11 window, it means that
      * the pointer has crossed to another native Wayland window, in this
      * case, pretend we entered the root window so that a LeaveNotify
      * event is emitted.
      */
-    if (xwl_seat->focus_window == NULL && xwl_seat->last_xwindow == ret) {
+    if (sprite_check_lost_focus(sprite, ret)) {
         sprite->spriteTraceGood = 1;
         return sprite->spriteTrace[0];
     }
 
-    xwl_seat->last_xwindow = ret;
-
     return ret;
 }
 
-- 
2.10.0