[gnome-desktop/gnome-3-8] idle-monitor: Make per-device monitor fallible

[Bastien Nocera <hadess src gnome org>]

commit 72a2bccb41f276fc864e2705405ac9230b3cdda1
Author: Bastien Nocera <hadess hadess net>
Date:   Mon Mar 25 08:53:09 2013 +0100

    idle-monitor: Make per-device monitor fallible
    
    https://mail.gnome.org/archives/release-team/2013-March/msg00289.html
    
    https://bugzilla.gnome.org/show_bug.cgi?id=696118

 libgnome-desktop/gnome-idle-monitor.c |   48 ++++++++++++++++++++++++++-------
 libgnome-desktop/test-idle-monitor.c  |    4 +++
 2 files changed, 42 insertions(+), 10 deletions(-)
---
diff --git a/libgnome-desktop/gnome-idle-monitor.c b/libgnome-desktop/gnome-idle-monitor.c
index 761ffa9..4882bc5 100644
--- a/libgnome-desktop/gnome-idle-monitor.c
+++ b/libgnome-desktop/gnome-idle-monitor.c
@@ -70,7 +70,11 @@ enum
 
 static GParamSpec *obj_props[PROP_LAST];
 
-G_DEFINE_TYPE (GnomeIdleMonitor, gnome_idle_monitor, G_TYPE_OBJECT)
+static void gnome_idle_monitor_initable_iface_init (GInitableIface *iface);
+
+G_DEFINE_TYPE_WITH_CODE (GnomeIdleMonitor, gnome_idle_monitor, G_TYPE_OBJECT,
+                        G_IMPLEMENT_INTERFACE (G_TYPE_INITABLE,
+                                               gnome_idle_monitor_initable_iface_init))
 
 static gint64
 _xsyncvalue_to_int64 (XSyncValue value)
@@ -279,10 +283,9 @@ init_xsync (GnomeIdleMonitor *monitor)
        }
 
        monitor->priv->counter = find_idletime_counter (monitor);
-       if (monitor->priv->counter == None) {
-               g_warning ("GnomeIdleMonitor: IDLETIME counter not found");
+       /* IDLETIME counter not found? */
+       if (monitor->priv->counter == None)
                return;
-       }
 
        monitor->priv->user_active_alarm = _xsync_alarm_set (monitor, XSyncNegativeTransition, 1, FALSE);
 
@@ -352,6 +355,30 @@ gnome_idle_monitor_constructed (GObject *object)
        init_xsync (monitor);
 }
 
+static gboolean
+gnome_idle_monitor_initable_init (GInitable     *initable,
+                                 GCancellable  *cancellable,
+                                 GError       **error)
+{
+       GnomeIdleMonitor *monitor;
+
+       monitor = GNOME_IDLE_MONITOR (initable);
+
+       if (monitor->priv->counter == None) {
+               g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
+                                    "Per-device idletime is not supported");
+               return FALSE;
+       }
+
+       return TRUE;
+}
+
+static void
+gnome_idle_monitor_initable_iface_init (GInitableIface *iface)
+{
+       iface->init = gnome_idle_monitor_initable_init;
+}
+
 static void
 gnome_idle_monitor_class_init (GnomeIdleMonitorClass *klass)
 {
@@ -399,7 +426,7 @@ gnome_idle_monitor_init (GnomeIdleMonitor *monitor)
 GnomeIdleMonitor *
 gnome_idle_monitor_new (void)
 {
-       return GNOME_IDLE_MONITOR (g_object_new (GNOME_TYPE_IDLE_MONITOR, NULL));
+       return GNOME_IDLE_MONITOR (g_initable_new (GNOME_TYPE_IDLE_MONITOR, NULL, NULL, NULL));
 }
 
 /**
@@ -407,14 +434,15 @@ gnome_idle_monitor_new (void)
  * @device: A #GdkDevice to get the idle time for.
  *
  * Returns: a new #GnomeIdleMonitor that tracks the device-specific
- * idletime for @device. To track server-global idletime for all
- * devices, use gnome_idle_monitor_new().
+ * idletime for @device. If device-specific idletime is not available,
+ * %NULL is returned, and @error is set. To track server-global
+ * idletime for all devices, use gnome_idle_monitor_new().
  */
 GnomeIdleMonitor *
-gnome_idle_monitor_new_for_device (GdkDevice *device)
+gnome_idle_monitor_new_for_device (GdkDevice  *device)
 {
-       return GNOME_IDLE_MONITOR (g_object_new (GNOME_TYPE_IDLE_MONITOR,
-                                                "device", device, NULL));
+       return GNOME_IDLE_MONITOR (g_initable_new (GNOME_TYPE_IDLE_MONITOR, NULL, NULL,
+                                                  "device", device, NULL));
 }
 
 /**
diff --git a/libgnome-desktop/test-idle-monitor.c b/libgnome-desktop/test-idle-monitor.c
index 1b808ff..16c3fdc 100644
--- a/libgnome-desktop/test-idle-monitor.c
+++ b/libgnome-desktop/test-idle-monitor.c
@@ -73,6 +73,10 @@ device_added_cb (GdkDeviceManager *manager,
 
        device_id = gdk_x11_device_get_id (device);
        monitor = gnome_idle_monitor_new_for_device (device);
+       if (!monitor) {
+               g_warning ("Per-device idletime monitor not available");
+               return;
+       }
 
        watch_id = gnome_idle_monitor_add_idle_watch (monitor,
                                                      IDLE_TIME,