From b9af7952a450b39d8bb042c19821a7d07b5027db Mon Sep 17 00:00:00 2001
From: Bastien Nocera <hadess@hadess.net>
Date: Mon, 21 Jan 2019 15:28:33 +0100
Subject: [PATCH] demo: Fix crash when there are no supported devices

Handle the empty list output from fp_discover_devs() when there are no
supported devices.

Closes: #146
---
 demo/gtk-libfprint-test.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/demo/gtk-libfprint-test.c b/demo/gtk-libfprint-test.c
index b23e38d..d0dd0c1 100644
--- a/demo/gtk-libfprint-test.c
+++ b/demo/gtk-libfprint-test.c
@@ -473,8 +473,17 @@ libfprint_demo_window_init (LibfprintDemoWindow *window)
 	setup_pollfds ();
 
 	discovered_devs = fp_discover_devs();
-	if (!discovered_devs)
+	if (!discovered_devs) {
+		libfprint_demo_set_mode (window, ERROR_MODE);
 		return;
+	}
+
+	/* Empty list? */
+	if (discovered_devs[0] == NULL) {
+		fp_dscv_devs_free (discovered_devs);
+		libfprint_demo_set_mode (window, EMPTY_MODE);
+		return;
+	}
 
 	if (!fp_driver_supports_imaging(fp_dscv_dev_get_driver(discovered_devs[0]))) {
 		libfprint_demo_set_mode (window, NOIMAGING_MODE);