Avoid unnecessary work if mount watching not specified (#585360)

If G_FILE_MONITOR_WATCH_MOUNTS isn't specified, don't do all the work
when the mtab changes.

gio/glocaldirectorymonitor.c

@@ -36,7 +36,8 @@
 enum
 {
   PROP_0,
-  PROP_DIRNAME
+  PROP_DIRNAME,
+  PROP_FLAGS
 };
 
 static gboolean g_local_directory_monitor_cancel (GFileMonitor      *monitor);
@@ -74,6 +75,9 @@ g_local_directory_monitor_set_property (GObject      *object,
     case PROP_DIRNAME:
       /* Do nothing */
       break;
+    case PROP_FLAGS:
+      /* Do nothing */
+      break;
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
       break;
@@ -89,6 +93,7 @@ g_local_directory_monitor_constructor (GType                  type,
   GLocalDirectoryMonitorClass *klass;
   GObjectClass *parent_class;
   GLocalDirectoryMonitor *local_monitor;
+  GFileMonitorFlags  flags = 0;
   const gchar *dirname = NULL;
   gint i;
 
@@ -106,13 +111,19 @@ g_local_directory_monitor_constructor (GType                  type,
         {
           g_warn_if_fail (G_VALUE_HOLDS_STRING (construct_properties[i].value));
           dirname = g_value_get_string (construct_properties[i].value);
-          break;
+        }
+      if (strcmp ("flags", g_param_spec_get_name (construct_properties[i].pspec)) == 0)
+        {
+          g_warn_if_fail (G_VALUE_HOLDS_FLAGS (construct_properties[i].value));
+          flags = g_value_get_flags (construct_properties[i].value);
         }
     }
 
   local_monitor->dirname = g_strdup (dirname);
+  local_monitor->flags = flags;
 
-  if (!klass->mount_notify)
+  if (!klass->mount_notify &&
+      (flags & G_FILE_MONITOR_WATCH_MOUNTS))
     {
 #ifdef G_OS_WIN32
       /*claim everything was mounted */
@@ -159,6 +170,16 @@ g_local_directory_monitor_class_init (GLocalDirectoryMonitorClass* klass)
                                                         G_PARAM_CONSTRUCT_ONLY|
                                                         G_PARAM_WRITABLE|
                                                         G_PARAM_STATIC_NAME|G_PARAM_STATIC_NICK|G_PARAM_STATIC_BLURB));
+  g_object_class_install_property (gobject_class,
+                                   PROP_FLAGS,
+                                   g_param_spec_flags ("flags",
+						       P_("Monitor flags"),
+						       P_("Monitor flags"),
+						       G_TYPE_FILE_MONITOR_FLAGS,
+						       0,
+						       G_PARAM_CONSTRUCT_ONLY|
+						       G_PARAM_WRITABLE|
+						       G_PARAM_STATIC_NAME|G_PARAM_STATIC_NICK|G_PARAM_STATIC_BLURB));
 
   klass->mount_notify = FALSE;
 }
@@ -268,7 +289,7 @@ _g_local_directory_monitor_new (const char         *dirname,
 
   monitor = NULL;
   if (type != G_TYPE_INVALID)
-    monitor = G_FILE_MONITOR (g_object_new (type, "dirname", dirname, NULL));
+    monitor = G_FILE_MONITOR (g_object_new (type, "dirname", dirname, "flags", flags, NULL));
   else
     g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_FAILED,
                          _("Unable to find default local directory monitor type"));

gio/glocaldirectorymonitor.h

@@ -45,6 +45,7 @@ struct _GLocalDirectoryMonitor
   GFileMonitor parent_instance;
 
   gchar             *dirname;
+  GFileMonitorFlags  flags;
   /* For mount emulation */
   GUnixMountMonitor *mount_monitor;
   gboolean           was_mounted;