[mutter/wip/carlosg/xdnd-error-traps] wayland/xdnd: Add error traps around Xdnd* IPC

[Carlos Garnacho <carlosg src gnome org>]

commit 6a86cfa39084539a5145cd36435db83258ed5b5a
Author: Carlos Garnacho <carlosg gnome org>
Date:   Tue Apr 7 19:16:16 2020 +0200

    wayland/xdnd: Add error traps around Xdnd* IPC
    
    Make all of them spew criticals, except for XdndLeave as it's feasible
    to expect the window we are sending the event to did disappear in the
    way (eg. if the window is destroyed while the DnD operation is ongoing
    and the pointer is over the window).

 src/wayland/meta-xwayland-dnd.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)
---
diff --git a/src/wayland/meta-xwayland-dnd.c b/src/wayland/meta-xwayland-dnd.c
index 6b75362ba..ea81d71be 100644
--- a/src/wayland/meta-xwayland-dnd.c
+++ b/src/wayland/meta-xwayland-dnd.c
@@ -145,6 +145,8 @@ xdnd_send_enter (MetaXWaylandDnd *dnd,
   gchar **p;
   struct wl_array *source_mime_types;
 
+  meta_x11_error_trap_push (x11_display);
+
   data_source = compositor->seat->data_device.dnd_data_source;
   xev.xclient.type = ClientMessage;
   xev.xclient.message_type = xdnd_atoms[ATOM_DND_ENTER];
@@ -189,6 +191,9 @@ xdnd_send_enter (MetaXWaylandDnd *dnd,
     }
 
   XSendEvent (xdisplay, dest, False, NoEventMask, &xev);
+
+  if (meta_x11_error_trap_pop_with_return (x11_display) != Success)
+    g_critical ("Error sending XdndEnter");
 }
 
 static void
@@ -205,7 +210,9 @@ xdnd_send_leave (MetaXWaylandDnd *dnd,
   xev.xclient.window = dest;
   xev.xclient.data.l[0] = x11_display->selection.xwindow;
 
+  meta_x11_error_trap_push (x11_display);
   XSendEvent (xdisplay, dest, False, NoEventMask, &xev);
+  meta_x11_error_trap_pop (x11_display);
 }
 
 static void
@@ -241,7 +248,11 @@ xdnd_send_position (MetaXWaylandDnd *dnd,
   xev.xclient.data.l[3] = time;
   xev.xclient.data.l[4] = action_to_atom (action);
 
+  meta_x11_error_trap_push (x11_display);
   XSendEvent (xdisplay, dest, False, NoEventMask, &xev);
+
+  if (meta_x11_error_trap_pop_with_return (x11_display) != Success)
+    g_critical ("Error sending XdndPosition");
 }
 
 static void
@@ -261,7 +272,11 @@ xdnd_send_drop (MetaXWaylandDnd *dnd,
   xev.xclient.data.l[0] = x11_display->selection.xwindow;
   xev.xclient.data.l[2] = time;
 
+  meta_x11_error_trap_push (x11_display);
   XSendEvent (xdisplay, dest, False, NoEventMask, &xev);
+
+  if (meta_x11_error_trap_pop_with_return (x11_display) != Success)
+    g_critical ("Error sending XdndDrop");
 }
 
 static void
@@ -289,7 +304,11 @@ xdnd_send_finished (MetaXWaylandDnd *dnd,
       xev.xclient.data.l[2] = action_to_atom (action);
     }
 
+  meta_x11_error_trap_push (x11_display);
   XSendEvent (xdisplay, dest, False, NoEventMask, &xev);
+
+  if (meta_x11_error_trap_pop_with_return (x11_display) != Success)
+    g_critical ("Error sending XdndFinished");
 }
 
 static void
@@ -297,6 +316,7 @@ xdnd_send_status (MetaXWaylandDnd *dnd,
                   Window           dest,
                   uint32_t         action)
 {
+  MetaX11Display *x11_display = meta_get_display ()->x11_display;
   Display *xdisplay = GDK_DISPLAY_XDISPLAY (gdk_display_get_default ());
   XEvent xev = { 0 };
 
@@ -312,7 +332,11 @@ xdnd_send_status (MetaXWaylandDnd *dnd,
   if (xev.xclient.data.l[4])
     xev.xclient.data.l[1] |= 1 << 0; /* Bit 1: dest accepts the drop */
 
+  meta_x11_error_trap_push (x11_display);
   XSendEvent (xdisplay, dest, False, NoEventMask, &xev);
+
+  if (meta_x11_error_trap_pop_with_return (x11_display) != Success)
+    g_critical ("Error sending Xdndstatus");
 }
 
 static void