core: Make sources network aware

If a source says that it requires the local network, or access to
the Internet to work properly, automatically hide it when the network
becomes unavailable, and show it when the network comes back on again.

This is implemented using GNetworkManager's connectivity property.
See https://bugzilla.gnome.org/show_bug.cgi?id=664562

Sources only need to set the "net:local" or "net:internet" tags to
be shown/hidden from applications depending on the network status.

https://bugzilla.gnome.org/show_bug.cgi?id=725148

2 files changed, 178 insertions, 5 deletions

diff --git a/src/grl-registry.c b/src/grl-registry.c
index 57b68cf..a72e5ce 100644
--- a/src/grl-registry.c
+++ b/src/grl-registry.c
@@ -62,6 +62,14 @@ GRL_LOG_DOMAIN(registry_log_domain);
 
 #define GRL_PLUGIN_INFO_MODULE "module"
 
+#define LOCAL_NET_TAG      "net:local"
+#define INTERNET_NET_TAG   "net:internet"
+
+#define SET_INVISIBLE_SOURCE(src, val)                          \
+  g_object_set_data(G_OBJECT(src), "invisible", GINT_TO_POINTER(val))
+#define SOURCE_IS_INVISIBLE(src)                                \
+  GPOINTER_TO_INT(g_object_get_data(G_OBJECT(src), "invisible"))
+
 #define GRL_REGISTRY_GET_PRIVATE(object)                        \
   (G_TYPE_INSTANCE_GET_PRIVATE((object),                        \
                                GRL_TYPE_REGISTRY,               \
@@ -85,6 +93,7 @@ struct _GrlRegistryPrivate {
   GSList *allowed_plugins;
   gboolean all_plugins_preloaded;
   struct KeyIDHandler key_id_handler;
+  GNetworkMonitor *netmon;
 };
 
 static void grl_registry_setup_ranks (GrlRegistry *registry);
@@ -109,6 +118,8 @@ static void shutdown_plugin (GrlPlugin *plugin);
 
 static void configs_free (GList *configs);
 
+static gboolean strv_contains (const char **strv, const char  *str);
+
 /* ================ GrlRegistry GObject ================ */
 
 enum {
@@ -185,6 +196,81 @@ grl_registry_class_init (GrlRegistryClass *klass)
 }
 
 static void
+network_changed_cb (GObject     *gobject,
+                    GParamSpec  *pspec,
+                    GrlRegistry *registry)
+{
+  GNetworkConnectivity connectivity;
+  gboolean network_available;
+  GHashTableIter iter;
+  GrlSource *current_source;
+
+  GRL_DEBUG ("Network availability changed");
+
+  g_object_get (G_OBJECT (registry->priv->netmon),
+                "connectivity", &connectivity,
+                "network-available", &network_available,
+                NULL);
+
+  GRL_DEBUG ("Connectivity level is %d, Network is %s",
+             connectivity, network_available ? "available" : "unavailable");
+
+  if (!network_available) {
+    g_hash_table_iter_init (&iter, registry->priv->sources);
+
+    while (g_hash_table_iter_next (&iter, NULL, (gpointer *) &current_source)) {
+      const char **tags = grl_source_get_tags (current_source);
+
+      if (!tags)
+        continue;
+
+      if ((strv_contains (tags, LOCAL_NET_TAG) ||
+           strv_contains (tags, INTERNET_NET_TAG)) &&
+          !SOURCE_IS_INVISIBLE(current_source)) {
+        GRL_DEBUG ("Network isn't available for '%s', hiding",
+                   grl_source_get_id (current_source));
+        SET_INVISIBLE_SOURCE(current_source, TRUE);
+        g_signal_emit (registry, registry_signals[SIG_SOURCE_REMOVED], 0, current_source);
+      }
+    }
+  } else {
+    g_hash_table_iter_init (&iter, registry->priv->sources);
+    while (g_hash_table_iter_next (&iter, NULL, (gpointer *) &current_source)) {
+      const char **tags = grl_source_get_tags (current_source);
+
+      if (!tags)
+        continue;
+
+      if (strv_contains (tags, LOCAL_NET_TAG) &&
+          SOURCE_IS_INVISIBLE(current_source)) {
+        GRL_DEBUG ("Local network became available for '%s', showing",
+                   grl_source_get_id (current_source));
+        SET_INVISIBLE_SOURCE(current_source, FALSE);
+        g_signal_emit (registry, registry_signals[SIG_SOURCE_ADDED], 0, current_source);
+      }
+
+      if (strv_contains (tags, INTERNET_NET_TAG) &&
+          connectivity == G_NETWORK_CONNECTIVITY_FULL &&
+          SOURCE_IS_INVISIBLE(current_source)) {
+        GRL_DEBUG ("Internet became available for '%s', showing",
+                   grl_source_get_id (current_source));
+        SET_INVISIBLE_SOURCE(current_source, FALSE);
+        g_signal_emit (registry, registry_signals[SIG_SOURCE_ADDED], 0, current_source);
+      }
+
+      if (strv_contains (tags, INTERNET_NET_TAG) &&
+          connectivity != G_NETWORK_CONNECTIVITY_FULL &&
+          !SOURCE_IS_INVISIBLE(current_source)) {
+        GRL_DEBUG ("Internet became unavailable for '%s', hiding",
+                   grl_source_get_id (current_source));
+        SET_INVISIBLE_SOURCE(current_source, TRUE);
+        g_signal_emit (registry, registry_signals[SIG_SOURCE_REMOVED], 0, current_source);
+      }
+    }
+  }
+}
+
+static void
 grl_registry_init (GrlRegistry *registry)
 {
   registry->priv = GRL_REGISTRY_GET_PRIVATE (registry);
@@ -199,6 +285,11 @@ grl_registry_init (GrlRegistry *registry)
     g_hash_table_new_full (g_direct_hash, g_direct_equal, NULL, NULL);
   registry->priv->system_keys =
     g_hash_table_new_full (g_str_hash, g_str_equal, NULL, (GDestroyNotify) g_param_spec_unref);
+  registry->priv->netmon = g_network_monitor_get_default ();
+  g_signal_connect (G_OBJECT (registry->priv->netmon), "notify::connectivity",
+                    G_CALLBACK (network_changed_cb), registry);
+  g_signal_connect (G_OBJECT (registry->priv->netmon), "notify::network-available",
+                    G_CALLBACK (network_changed_cb), registry);
 
   key_id_handler_init (&registry->priv->key_id_handler);
 
@@ -213,6 +304,71 @@ configs_free (GList *configs)
   g_list_free_full (configs, g_object_unref);
 }
 
+static gboolean
+strv_contains (const char **strv,
+               const char  *str)
+{
+  const char **s = strv;
+
+  while (*s) {
+    if (g_str_equal (str, *s))
+      return TRUE;
+    s++;
+  }
+
+  return FALSE;
+}
+
+static void
+update_source_visibility (GrlRegistry *registry,
+                          GrlSource   *source)
+{
+  GNetworkConnectivity connectivity;
+  gboolean network_available;
+  const char **tags;
+  gboolean needs_local, needs_inet;
+
+  tags = grl_source_get_tags (source);
+  if (!tags)
+    return;
+
+  needs_local = strv_contains (tags, LOCAL_NET_TAG);
+  needs_inet = strv_contains (tags, INTERNET_NET_TAG);
+
+  if (!needs_local &&
+      !needs_inet)
+    return;
+
+  g_object_get (G_OBJECT (registry->priv->netmon),
+                "connectivity", &connectivity,
+                "network-available", &network_available,
+                NULL);
+
+  GRL_DEBUG ("Connectivity level is %d, Network is %s",
+             connectivity, network_available ? "available" : "unavailable");
+  GRL_DEBUG ("Source %s needs %s %s%s",
+             grl_source_get_id (source),
+             needs_local ? "local network" : "",
+             needs_inet && needs_local ? " and " : "",
+             needs_inet ? "Internet" : "");
+
+  if (!network_available) {
+    if (needs_local || needs_inet) {
+      GRL_DEBUG ("Network isn't available for '%s', hiding",
+                 grl_source_get_id (source));
+      SET_INVISIBLE_SOURCE(source, TRUE);
+    }
+  } else {
+    if (connectivity != G_NETWORK_CONNECTIVITY_FULL) {
+      if (needs_inet) {
+        GRL_DEBUG ("Internet isn't available for '%s', hiding",
+                   grl_source_get_id (source));
+        SET_INVISIBLE_SOURCE(source, TRUE);
+      }
+    }
+  }
+}
+
 static void
 config_source_rank (GrlRegistry *registry,
                     const gchar *source_id,
@@ -842,7 +998,11 @@ grl_registry_register_source (GrlRegistry *registry,
   /* Set source rank */
   set_source_rank (registry, source);
 
-  g_signal_emit (registry, registry_signals[SIG_SOURCE_ADDED], 0, source);
+  /* Update whether it should be invisible */
+  update_source_visibility (registry, source);
+
+  if (!SOURCE_IS_INVISIBLE(source))
+    g_signal_emit (registry, registry_signals[SIG_SOURCE_ADDED], 0, source);
 
   return TRUE;
 }
@@ -1173,11 +1333,16 @@ GrlSource *
 grl_registry_lookup_source (GrlRegistry *registry,
                             const gchar *source_id)
 {
+  GrlSource *source;
+
   g_return_val_if_fail (GRL_IS_REGISTRY (registry), NULL);
   g_return_val_if_fail (source_id != NULL, NULL);
 
-  return (GrlSource *) g_hash_table_lookup (registry->priv->sources,
-                                            source_id);
+  source = (GrlSource *) g_hash_table_lookup (registry->priv->sources,
+                                              source_id);
+  if (!SOURCE_IS_INVISIBLE(source))
+    return source;
+  return NULL;
 }
 
 /**
@@ -1207,7 +1372,8 @@ grl_registry_get_sources (GrlRegistry *registry,
 
   g_hash_table_iter_init (&iter, registry->priv->sources);
   while (g_hash_table_iter_next (&iter, NULL, (gpointer *) &current_source)) {
-    source_list = g_list_prepend (source_list, current_source);
+    if (!SOURCE_IS_INVISIBLE(current_source))
+      source_list = g_list_prepend (source_list, current_source);
   }
 
   if (ranked) {
@@ -1250,7 +1416,8 @@ grl_registry_get_sources_by_operations (GrlRegistry *registry,
     GrlSupportedOps source_ops;
     source_ops =
       grl_source_supported_operations (source);
-    if ((source_ops & ops) == ops) {
+    if ((source_ops & ops) == ops &&
+        !SOURCE_IS_INVISIBLE(source)) {
       source_list = g_list_prepend (source_list, source);
     }
   }
diff --git a/src/grl-source.c b/src/grl-source.c
index a84f405..061f45b 100644
--- a/src/grl-source.c
+++ b/src/grl-source.c
@@ -455,6 +455,12 @@ grl_source_class_init (GrlSourceClass *source_class)
    *   avoid showing the user's own data in their interfaces, or integrate it
    *   in the user's local collection.
    *
+   *   "net:local", or "net:internet"
+   *   The source requires a connection to the local network, or a connection
+   *   to the Internet. Sources with those tags will be automatically hidden
+   *   from the application's reach when such networks aren't available, or
+   *   we're not connected to a network.
+   *
    * Since: 0.2.10
    */
   g_object_class_install_property (gobject_class,