[gnome-software/gnome-3-20] fedora-distro-upgrades: Add fallbacks for the background image

[Kalev Lember <klember src gnome org>]

commit fc43b506c6a41d8e800c03aed9b9598f68ad6f7f
Author: Kalev Lember <klember redhat com>
Date:   Thu Jun 2 08:44:39 2016 +0200

    fedora-distro-upgrades: Add fallbacks for the background image

 src/plugins/gs-plugin-fedora-distro-upgrades.c |   25 +++++++++++++++++++++--
 1 files changed, 22 insertions(+), 3 deletions(-)
---
diff --git a/src/plugins/gs-plugin-fedora-distro-upgrades.c b/src/plugins/gs-plugin-fedora-distro-upgrades.c
index af43ca8..346cda7 100644
--- a/src/plugins/gs-plugin-fedora-distro-upgrades.c
+++ b/src/plugins/gs-plugin-fedora-distro-upgrades.c
@@ -262,6 +262,24 @@ parse_pkgdb_collections_data (const gchar *data,
        return distros;
 }
 
+static gchar *
+get_upgrade_css_background (guint version)
+{
+       g_autofree gchar *filename1 = NULL;
+       g_autofree gchar *filename2 = NULL;
+
+       filename1 = g_strdup_printf ("/usr/share/backgrounds/f%d/default/standard/f%d.png", version, version);
+       if (g_file_test (filename1, G_FILE_TEST_EXISTS))
+               return g_strdup_printf ("url('%s')", filename1);
+
+       filename2 = g_strdup_printf ("/usr/share/gnome-software/backgrounds/f%d.png", version);
+       if (g_file_test (filename2, G_FILE_TEST_EXISTS))
+               return g_strdup_printf ("url('%s')", filename2);
+
+       /* fall back to solid colour */
+       return g_strdup_printf ("#151E65");
+}
+
 /**
  * gs_plugin_add_distro_upgrades:
  */
@@ -295,6 +313,7 @@ gs_plugin_add_distro_upgrades (GsPlugin *plugin,
                DistroInfo *distro_info = g_ptr_array_index (distros, i);
                g_autofree gchar *app_id = NULL;
                g_autofree gchar *app_version = NULL;
+               g_autofree gchar *background = NULL;
                g_autofree gchar *url = NULL;
                g_autofree gchar *css = NULL;
                g_autoptr(GsApp) app = NULL;
@@ -352,11 +371,11 @@ gs_plugin_add_distro_upgrades (GsPlugin *plugin,
                gs_app_set_url (app, AS_URL_KIND_HOMEPAGE, url);
 
                /* use a fancy background */
-               css = g_strdup_printf ("background: 
url('/usr/share/backgrounds/f%i/default/standard/f%i.png');"
+               background = get_upgrade_css_background (distro_info->version);
+               css = g_strdup_printf ("background: %s;"
                                       "background-position: center;"
                                       "background-size: cover;",
-                                      distro_info->version,
-                                      distro_info->version);
+                                      background);
                gs_app_set_metadata (app, "GnomeSoftware::UpgradeBanner-css", css);
 
                gs_plugin_add_app (list, app);