gnetworkmonitornm: Fix network available detection

The network-available property can be asserted by querying the NMState
describing the current overval network state, instead of the
NMConnectivityState. The advantage of the NMState is that is reflects
immediately the network state modification, while the connectivity
state is tested at a fixed frequency.

gio/gnetworkmonitornm.c

@@ -52,6 +52,19 @@ typedef enum {
   NM_CONNECTIVITY_FULL
 } NMConnectivityState;
 
+/* Copied from https://developer.gnome.org/libnm-util/stable/libnm-util-NetworkManager.html#NMState;
+ * used inline to avoid a NetworkManager dependency from GLib. */
+typedef enum {
+  NM_STATE_UNKNOWN          = 0,
+  NM_STATE_ASLEEP           = 10,
+  NM_STATE_DISCONNECTED     = 20,
+  NM_STATE_DISCONNECTING    = 30,
+  NM_STATE_CONNECTING       = 40,
+  NM_STATE_CONNECTED_LOCAL  = 50,
+  NM_STATE_CONNECTED_SITE   = 60,
+  NM_STATE_CONNECTED_GLOBAL = 70,
+} NMState;
+
 struct _GNetworkMonitorNMPrivate
 {
   GDBusProxy *proxy;
@@ -155,11 +168,19 @@ sync_properties (GNetworkMonitorNM *nm,
                  gboolean           emit_signals)
 {
   GVariant *v;
+  NMState nm_state;
   NMConnectivityState nm_connectivity;
   gboolean new_network_available;
   gboolean new_network_metered;
   GNetworkConnectivity new_connectivity;
 
+  v = g_dbus_proxy_get_cached_property (nm->priv->proxy, "State");
+  if (!v)
+    return;
+
+  nm_state = g_variant_get_uint32 (v);
+  g_variant_unref (v);
+
   v = g_dbus_proxy_get_cached_property (nm->priv->proxy, "Connectivity");
   if (!v)
     return;
@@ -167,14 +188,26 @@ sync_properties (GNetworkMonitorNM *nm,
   nm_connectivity = g_variant_get_uint32 (v);
   g_variant_unref (v);
 
-  if (nm_connectivity == NM_CONNECTIVITY_UNKNOWN ||
-      nm_connectivity == NM_CONNECTIVITY_NONE)
+  if (nm_state <= NM_STATE_CONNECTED_LOCAL)
     {
       new_network_available = FALSE;
       new_network_metered = FALSE;
       new_connectivity = G_NETWORK_CONNECTIVITY_LOCAL;
     }
-  else
+  else if (nm_state <= NM_STATE_CONNECTED_SITE)
+    {
+      new_network_available = FALSE;
+      new_network_metered = FALSE;
+      if (nm_connectivity == NM_CONNECTIVITY_PORTAL)
+        {
+          new_connectivity = G_NETWORK_CONNECTIVITY_PORTAL;
+        }
+      else
+        {
+          new_connectivity = G_NETWORK_CONNECTIVITY_LIMITED;
+        }
+    }
+  else /* nm_state == NM_STATE_CONNECTED_FULL */
     {
 
       /* this is only available post NM 1.0 */