master 4544651: Work around some mysterious touch ownership race on GNOME Shell

[Po Lu]

branch: master
commit 4544651b3f62ce4a104a058e8c6aee42c23b76bc
Author: Po Lu <luangruo@yahoo.com>
Commit: Po Lu <luangruo@yahoo.com>

    Work around some mysterious touch ownership race on GNOME Shell
    
    * src/xterm.c (x_unlink_touch_point): Return if touchpoint was
    actually unlinked.
    (handle_one_xevent): Catch and ignore errors during touch
    sequence grabbing.
---
 src/xterm.c | 88 +++++++++++++++++++++++++++++++++++--------------------------
 1 file changed, 51 insertions(+), 37 deletions(-)

diff --git a/src/xterm.c b/src/xterm.c
index 03f509b..7456b3b 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -579,7 +579,7 @@ xi_link_touch_point (struct xi_device_t *device,
   device->touchpoints = touchpoint;
 }
 
-static void
+static bool
 xi_unlink_touch_point (int detail,
                       struct xi_device_t *device)
 {
@@ -596,9 +596,11 @@ xi_unlink_touch_point (int detail,
            last->next = tem->next;
 
          xfree (tem);
-         return;
+         return true;
        }
     }
+
+  return false;
 }
 
 static struct xi_touch_point_t *
@@ -10887,37 +10889,45 @@ handle_one_xevent (struct x_display_info *dpyinfo,
 
              if (f && device->direct_p)
                {
-                 xi_link_touch_point (device, xev->detail, xev->event_x,
-                                      xev->event_y);
+                 x_catch_errors (dpyinfo->display);
+                 XIAllowTouchEvents (dpyinfo->display, xev->deviceid,
+                                     xev->detail, xev->event, XIAcceptTouch);
+                 if (!x_had_errors_p (dpyinfo->display))
+                   {
+                     xi_link_touch_point (device, xev->detail, xev->event_x,
+                                          xev->event_y);
 
 #ifdef HAVE_GTK3
-                 if (FRAME_X_OUTPUT (f)->menubar_widget
-                     && xg_event_is_for_menubar (f, event))
-                   {
-                     bool was_waiting_for_input = waiting_for_input;
-                     /* This hack was adopted from the NS port.  Whether
-                        or not it is actually safe is a different story
-                        altogether.  */
-                     if (waiting_for_input)
-                       waiting_for_input = 0;
-                     set_frame_menubar (f, true);
-                     waiting_for_input = was_waiting_for_input;
-                   }
+                     if (FRAME_X_OUTPUT (f)->menubar_widget
+                         && xg_event_is_for_menubar (f, event))
+                       {
+                         bool was_waiting_for_input = waiting_for_input;
+                         /* This hack was adopted from the NS port.  Whether
+                            or not it is actually safe is a different story
+                            altogether.  */
+                         if (waiting_for_input)
+                           waiting_for_input = 0;
+                         set_frame_menubar (f, true);
+                         waiting_for_input = was_waiting_for_input;
+                       }
 #endif
 
-                 inev.ie.kind = TOUCHSCREEN_BEGIN_EVENT;
-                 inev.ie.timestamp = xev->time;
-                 XSETFRAME (inev.ie.frame_or_window, f);
-                 XSETINT (inev.ie.x, lrint (xev->event_x));
-                 XSETINT (inev.ie.y, lrint (xev->event_y));
-                 XSETINT (inev.ie.arg, xev->detail);
-
-                 XIAllowTouchEvents (dpyinfo->display, xev->deviceid,
-                                     xev->detail, xev->event, XIAcceptTouch);
+                     inev.ie.kind = TOUCHSCREEN_BEGIN_EVENT;
+                     inev.ie.timestamp = xev->time;
+                     XSETFRAME (inev.ie.frame_or_window, f);
+                     XSETINT (inev.ie.x, lrint (xev->event_x));
+                     XSETINT (inev.ie.y, lrint (xev->event_y));
+                     XSETINT (inev.ie.arg, xev->detail);
+                   }
+                 x_uncatch_errors_after_check ();
                }
              else
-               XIAllowTouchEvents (dpyinfo->display, xev->deviceid,
-                                   xev->detail, xev->event, XIRejectTouch);
+               {
+                 x_catch_errors (dpyinfo->display);
+                 XIAllowTouchEvents (dpyinfo->display, xev->deviceid,
+                                     xev->detail, xev->event, XIRejectTouch);
+                 x_uncatch_errors ();
+               }
 
              goto XI_OTHER;
            }
@@ -10965,24 +10975,28 @@ handle_one_xevent (struct x_display_info *dpyinfo,
          case XI_TouchEnd:
            {
              struct xi_device_t *device;
+             bool unlinked_p;
 
              device = xi_device_from_id (dpyinfo, xev->deviceid);
 
              if (!device)
                goto XI_OTHER;
 
-             xi_unlink_touch_point (xev->detail, device);
-
-             f = x_any_window_to_frame (dpyinfo, xev->event);
+             unlinked_p = xi_unlink_touch_point (xev->detail, device);
 
-             if (f && device->direct_p)
+             if (unlinked_p)
                {
-                 inev.ie.kind = TOUCHSCREEN_END_EVENT;
-                 inev.ie.timestamp = xev->time;
-                 XSETFRAME (inev.ie.frame_or_window, f);
-                 XSETINT (inev.ie.x, lrint (xev->event_x));
-                 XSETINT (inev.ie.y, lrint (xev->event_y));
-                 XSETINT (inev.ie.arg, xev->detail);
+                 f = x_any_window_to_frame (dpyinfo, xev->event);
+
+                 if (f && device->direct_p)
+                   {
+                     inev.ie.kind = TOUCHSCREEN_END_EVENT;
+                     inev.ie.timestamp = xev->time;
+                     XSETFRAME (inev.ie.frame_or_window, f);
+                     XSETINT (inev.ie.x, lrint (xev->event_x));
+                     XSETINT (inev.ie.y, lrint (xev->event_y));
+                     XSETINT (inev.ie.arg, xev->detail);
+                   }
                }
 
              goto XI_OTHER;