[gtk/wip/carlosg/selection-null-checks: 1/2] gdk/wayland: Avoid invalid memory access on cancellation

[Carlos Garnacho <carlosg src gnome org>]

commit 6893118510c9ddc904eeb0bb4505d4efa6c3b387
Author: Carlos Garnacho <carlosg gnome org>
Date:   Thu Feb 20 14:03:50 2020 +0100

    gdk/wayland: Avoid invalid memory access on cancellation
    
    The only way to have G_IO_ERROR_CANCELLED in the write callback
    goes through having the array of pending writers already cleared.
    It should not access the invalid AsyncWriteData and StoredSelection
    in that case.

 gdk/wayland/gdkselection-wayland.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)
---
diff --git a/gdk/wayland/gdkselection-wayland.c b/gdk/wayland/gdkselection-wayland.c
index d8cb2b8795..b675437951 100644
--- a/gdk/wayland/gdkselection-wayland.c
+++ b/gdk/wayland/gdkselection-wayland.c
@@ -734,13 +734,14 @@ async_write_data_cb (GObject      *object,
                                                 res, &error);
   if (error)
     {
-      if (error->domain != G_IO_ERROR ||
-          error->code != G_IO_ERROR_CANCELLED)
-        g_warning ("Error writing selection data: %s", error->message);
+      if (!g_error_matches (error, G_IO_ERROR, G_IO_ERROR_CANCELLED))
+        {
+          g_warning ("Error writing selection data: %s", error->message);
+          g_ptr_array_remove_fast (write_data->stored_selection->pending_writes,
+                                   write_data);
+        }
 
       g_error_free (error);
-      g_ptr_array_remove_fast (write_data->stored_selection->pending_writes,
-                               write_data);
       return;
     }