[ghex] appwin: Only attempt to set direct buffer if it can be loaded

[Logan Rathbone <larathbone src gnome org>]

commit 274fc1f3136f51d164e0c456aa161c0dbf92d059
Author: Logan Rathbone <poprocks gmail com>
Date:   Thu Jun 16 23:29:37 2022 -0400

    appwin: Only attempt to set direct buffer if it can be loaded

 src/ghex-application-window.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)
---
diff --git a/src/ghex-application-window.c b/src/ghex-application-window.c
index 8753a01..32b39e9 100644
--- a/src/ghex-application-window.c
+++ b/src/ghex-application-window.c
@@ -2212,7 +2212,12 @@ ghex_application_window_open_file (GHexApplicationWindow *self, GFile *file)
 
                        g_debug ("%s: attempting to set buffer to `direct`", __func__);
                        buf = hex_buffer_util_new ("direct", file);
-                       hex_document_set_buffer (doc, buf);
+                       if (buf)
+                               hex_document_set_buffer (doc, buf);
+                       else
+                               g_debug ("%s: setting buffer to `direct` failed. If this is "
+                                               "an attempt to open a block device, it will likely fail.",
+                                               __func__);
                }
 
                gh = HEX_WIDGET(hex_widget_new (doc));