Warn running in Demo Mode

src/Core/Client.vala

@@ -110,6 +110,10 @@ public class AppCenterCore.Client : Object {
     public async void update_cache (bool force = false, CacheUpdateType cache_update_type = CacheUpdateType.ALL) {
         cancellable.reset ();
 
+        if (Utils.is_running_in_demo_mode ()) {
+            return;
+        }
+
         debug ("update cache called %s", force.to_string ());
         bool success = false;
 

src/MainWindow.vala

@@ -278,6 +278,24 @@ public class AppCenter.MainWindow : Hdy.ApplicationWindow {
         var box = new Gtk.Box (Gtk.Orientation.VERTICAL, 0);
         box.add (headerbar);
         box.add (network_info_bar);
+
+        if (Utils.is_running_in_demo_mode ()) {
+            var demo_mode_info_bar_label = new Gtk.Label ("<b>%s</b> %s".printf (
+                _("Running in Demo Mode"),
+                _("Install %s to browse and install apps.").printf (Environment.get_os_info (GLib.OsInfoKey.NAME))
+            )) {
+                use_markup = true,
+                wrap = true
+            };
+
+            var demo_mode_info_bar = new Gtk.InfoBar () {
+                message_type = Gtk.MessageType.WARNING
+            };
+            demo_mode_info_bar.get_content_area ().add (demo_mode_info_bar_label);
+
+            box.add (demo_mode_info_bar);
+        }
+
         box.add (overlay);
         box.show_all ();
 

src/Utils.vala

@@ -139,4 +139,21 @@ namespace Utils {
                            .replace (">", ">")
                            .replace ("'", "'");
     }
+
+    public static bool is_running_in_demo_mode () {
+        var proc_cmdline = File.new_for_path ("/proc/cmdline");
+        try {
+            var @is = proc_cmdline.read ();
+            var dis = new DataInputStream (@is);
+
+            var line = dis.read_line ();
+            if ("boot=casper" in line || "boot=live" in line || "rd.live.image" in line) {
+                return true;
+            }
+        } catch (Error e) {
+            critical ("Couldn't detect if running in Demo Mode: %s", e.message);
+        }
+
+        return false;
+    }
 }