gsettings-tool: Support completion for enum values

https://bugzilla.gnome.org/show_bug.cgi?id=631264

gio/gsettings-bash-completion.sh

@@ -38,6 +38,24 @@ __gsettings() {
           ;;
       esac
       ;;
+
+    4)
+      case "${COMP_WORDS[1]}" in
+        set)
+          range=($(gsettings range ${COMP_WORDS[2]} ${COMP_WORDS[3]} 2> /dev/null))
+          case "${range[0]}" in
+            enum)
+              unset range[0]
+             ;;
+            *)
+              unset range
+             ;;
+          esac
+          local IFS=$'\n'
+          choices="${range[*]}"
+          ;;
+      esac
+      ;;
   esac
 
   local IFS=$'\n'

gio/gsettings-tool.c

@@ -394,12 +394,27 @@ gsettings_set (GSettings   *settings,
   GError *error = NULL;
   GVariant *existing;
   GVariant *new;
+  gchar *freeme = NULL;
 
   existing = g_settings_get_value (settings, key);
   type = g_variant_get_type (existing);
 
+parse:
   new = g_variant_parse (type, value, NULL, NULL, &error);
 
+  /* A common error is to specify a string with single quotes
+   * (or use completion for that), and forget that the shell
+   * will eat one level of quoting, resulting in 'unknown keyword'
+   * error from the gvariant parser.
+   * To handle this case, try to parse again with an extra level
+   * of quotes.
+   */
+  if (new == NULL && !freeme && strstr (error->message, "unknown keyword"))
+    {
+      value = freeme = g_strdup_printf ("\"%s\"", value);
+      goto parse;
+    }
+
   if (new == NULL)
     {
       g_printerr ("%s\n", error->message);
@@ -418,6 +433,8 @@ gsettings_set (GSettings   *settings,
   g_variant_unref (new);
 
   g_settings_sync ();
+
+  g_free (freeme);
 }
 
 static int