object-manager: implement the 'installed' signal and improve state management

The 'installed' signal can be used to know that there are no
known objects that are being prepared internally, so the object
manager is ready to use.

This also improves internal state management so that the 'objects-changed'
signal cannot be fired earlier than it should. Previously there
were corner cases with complex proxy features, as the object manager
relied on the fact that after a core 'sync' it is safe to assume
that all proxies are augmented... that's not always the case.

lib/wp/node.c

@@ -72,11 +72,16 @@ wp_node_finalize (GObject * object)
   G_OBJECT_CLASS (wp_node_parent_class)->finalize (object);
 }
 
+static void
+wp_node_on_ports_om_installed (WpObjectManager *ports_om, WpNode * self)
+{
+  wp_proxy_set_feature_ready (WP_PROXY (self), WP_NODE_FEATURE_PORTS);
+}
+
 static void
 wp_node_emit_ports_changed (WpObjectManager *ports_om, WpNode * self)
 {
   g_signal_emit (self, signals[SIGNAL_PORTS_CHANGED], 0);
-  wp_proxy_set_feature_ready (WP_PROXY (self), WP_NODE_FEATURE_PORTS);
 }
 
 static void
@@ -111,16 +116,12 @@ wp_node_ensure_feature_ports (WpNode * self, guint32 bound_id)
         g_variant_builder_end (&b),
         WP_PROXY_FEATURES_STANDARD);
 
+    g_signal_connect_object (priv->ports_om, "installed",
+        G_CALLBACK (wp_node_on_ports_om_installed), self, 0);
     g_signal_connect_object (priv->ports_om, "objects-changed",
         G_CALLBACK (wp_node_emit_ports_changed), self, 0);
 
     wp_core_install_object_manager (core, priv->ports_om);
-
-    /* special case: we have no ports available, therefore we should already
-       report that the feature is enabled; otherwise, the feature will be
-       enabled as soon as the port proxies are available */
-    if (priv->info->n_input_ports + priv->info->n_output_ports == 0)
-      wp_proxy_set_feature_ready (WP_PROXY (self), WP_NODE_FEATURE_PORTS);
   }
 }
 

lib/wp/object-manager.c

@@ -66,7 +66,10 @@ struct _WpObjectManager
   /* objects that we are interested in, without a ref */
   GPtrArray *objects;
 
-  gboolean pending_objchanged;
+  gboolean installed;
+  gboolean changed;
+  guint pending_objects;
+  GSource *idle_source;
 };
 
 enum {
@@ -78,6 +81,7 @@ enum {
   SIGNAL_OBJECT_ADDED,
   SIGNAL_OBJECT_REMOVED,
   SIGNAL_OBJECTS_CHANGED,
+  SIGNAL_INSTALLED,
   LAST_SIGNAL,
 };
 
@@ -91,7 +95,9 @@ wp_object_manager_init (WpObjectManager * self)
   g_weak_ref_init (&self->core, NULL);
   pw_array_init (&self->interests, sizeof (struct interest));
   self->objects = g_ptr_array_new ();
-  self->pending_objchanged = FALSE;
+  self->installed = FALSE;
+  self->changed = FALSE;
+  self->pending_objects = 0;
 }
 
 static void
@@ -100,6 +106,10 @@ wp_object_manager_finalize (GObject * object)
   WpObjectManager *self = WP_OBJECT_MANAGER (object);
   struct interest *i;
 
+  if (self->idle_source) {
+    g_source_destroy (self->idle_source);
+    g_clear_pointer (&self->idle_source, g_source_unref);
+  }
   g_clear_pointer (&self->objects, g_ptr_array_unref);
 
   pw_array_for_each (i, &self->interests) {
@@ -112,22 +122,6 @@ wp_object_manager_finalize (GObject * object)
   G_OBJECT_CLASS (wp_object_manager_parent_class)->finalize (object);
 }
 
-static void
-wp_object_manager_set_property (GObject * object, guint property_id,
-    const GValue * value, GParamSpec * pspec)
-{
-  WpObjectManager *self = WP_OBJECT_MANAGER (object);
-
-  switch (property_id) {
-  case PROP_CORE:
-    g_weak_ref_set (&self->core, g_value_get_object (value));
-    break;
-  default:
-    G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
-    break;
-  }
-}
-
 static void
 wp_object_manager_get_property (GObject * object, guint property_id,
     GValue * value, GParamSpec * pspec)
@@ -151,13 +145,12 @@ wp_object_manager_class_init (WpObjectManagerClass * klass)
 
   object_class->finalize = wp_object_manager_finalize;
   object_class->get_property = wp_object_manager_get_property;
-  object_class->set_property = wp_object_manager_set_property;
 
   /* Install the properties */
 
   g_object_class_install_property (object_class, PROP_CORE,
       g_param_spec_object ("core", "core", "The WpCore", WP_TYPE_CORE,
-          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
+          G_PARAM_READABLE | G_PARAM_STATIC_STRINGS));
 
   /**
    * WpObjectManager::object-added:
@@ -197,6 +190,19 @@ wp_object_manager_class_init (WpObjectManagerClass * klass)
   signals[SIGNAL_OBJECTS_CHANGED] = g_signal_new (
       "objects-changed", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_FIRST,
       0, NULL, NULL, NULL, G_TYPE_NONE, 0);
+
+  /**
+   * WpObjectManager::installed:
+   * @self: the object manager
+   *
+   * This is emitted once after the object manager is installed with
+   * wp_core_install_object_manager(). If there are objects that need
+   * to be prepared asynchronously internally, emission of this signal is
+   * delayed until all objects are ready.
+   */
+  signals[SIGNAL_INSTALLED] = g_signal_new (
+      "installed", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_FIRST,
+      0, NULL, NULL, NULL, G_TYPE_NONE, 0);
 }
 
 /**
@@ -571,26 +577,62 @@ wp_object_manager_is_interested_in_global (WpObjectManager * self,
   return FALSE;
 }
 
-static void
-sync_emit_objects_changed (WpCore *core, GAsyncResult *res, gpointer data)
+static gboolean
+idle_emit_objects_changed (WpObjectManager * self)
 {
-  g_autoptr (WpObjectManager) self = WP_OBJECT_MANAGER (data);
+  g_clear_pointer (&self->idle_source, g_source_unref);
 
+  if (G_UNLIKELY (!self->installed)) {
+    wp_trace_object (self, "installed");
+    g_signal_emit (self, signals[SIGNAL_INSTALLED], 0);
+    self->installed = TRUE;
+  }
   g_signal_emit (self, signals[SIGNAL_OBJECTS_CHANGED], 0);
-  self->pending_objchanged = FALSE;
+
+  return G_SOURCE_REMOVE;
 }
 
-static inline void
-schedule_emit_objects_changed (WpObjectManager * self)
+static void
+wp_object_manager_maybe_objects_changed (WpObjectManager * self)
 {
-  if (self->pending_objchanged)
+  /* always wait until there are no pending objects */
+  if (self->pending_objects > 0)
     return;
 
-  g_autoptr (WpCore) core = g_weak_ref_get (&self->core);
-  if (core) {
-    wp_core_sync (core, NULL, (GAsyncReadyCallback)sync_emit_objects_changed,
-        g_object_ref (self));
-    self->pending_objchanged = TRUE;
+  /* Emit 'objects-changed' when:
+   * - there are no pending objects
+   * - object-added or object-removed has been emitted at least once
+   */
+  if (self->changed) {
+    self->changed = FALSE;
+
+    /* schedule emission in idle; if it is already scheduled from earlier,
+       there is nothing to do; we will emit objects-changed once for all
+       changes... win-win */
+    if (!self->idle_source) {
+      g_autoptr (WpCore) core = g_weak_ref_get (&self->core);
+      if (core) {
+        wp_core_idle_add (core, &self->idle_source,
+            (GSourceFunc) idle_emit_objects_changed, self, NULL);
+      }
+    }
+  }
+  /* Emit 'installed' when:
+   * - there are no pending objects
+   * - !changed: there was no object added
+   * - !installed: not already installed
+   * - the registry does not have pending globals; these may be interesting
+   * to our object manager, so let's wait a bit until they are released
+   * and re-evaluate again later
+   */
+  else if (!self->installed) {
+    g_autoptr (WpCore) core = g_weak_ref_get (&self->core);
+    WpRegistry *reg = wp_core_get_registry (core);
+    if (reg->tmp_globals->len == 0) {
+      wp_trace_object (self, "installed");
+      g_signal_emit (self, signals[SIGNAL_INSTALLED], 0);
+      self->installed = TRUE;
+    }
   }
 }
 
@@ -600,16 +642,20 @@ on_proxy_ready (GObject * proxy, GAsyncResult * res, gpointer data)
   g_autoptr (WpObjectManager) self = WP_OBJECT_MANAGER (data);
   g_autoptr (GError) error = NULL;
 
+  self->pending_objects--;
+
   if (!wp_proxy_augment_finish (WP_PROXY (proxy), res, &error)) {
     wp_message_object (self, "proxy augment failed: %s", error->message);
-    return;
+  } else {
+    g_ptr_array_add (self->objects, proxy);
+    g_signal_emit (self, signals[SIGNAL_OBJECT_ADDED], 0, proxy);
+    self->changed = TRUE;
   }
 
-  g_ptr_array_add (self->objects, proxy);
-  g_signal_emit (self, signals[SIGNAL_OBJECT_ADDED], 0, proxy);
-  schedule_emit_objects_changed (self);
+  wp_object_manager_maybe_objects_changed (self);
 }
 
+/* caller must also call wp_object_manager_maybe_objects_changed() after */
 static void
 wp_object_manager_add_global (WpObjectManager * self, WpGlobal * global)
 {
@@ -618,27 +664,34 @@ wp_object_manager_add_global (WpObjectManager * self, WpGlobal * global)
   if (wp_object_manager_is_interested_in_global (self, global, &features)) {
     g_autoptr (WpCore) core = g_weak_ref_get (&self->core);
 
+    self->pending_objects++;
+
     if (!global->proxy)
       global->proxy = g_object_new (global->type,
           "core", core,
           "global", global,
           NULL);
 
+    wp_trace_object (self, "adding global:%u -> " WP_OBJECT_FORMAT,
+        global->id, WP_OBJECT_ARGS (global->proxy));
+
     wp_proxy_augment (global->proxy, features, NULL, on_proxy_ready,
         g_object_ref (self));
   }
 }
 
+/* caller must also call wp_object_manager_maybe_objects_changed() after */
 static void
 wp_object_manager_add_object (WpObjectManager * self, gpointer object)
 {
   if (wp_object_manager_is_interested_in_object (self, object)) {
     g_ptr_array_add (self->objects, object);
     g_signal_emit (self, signals[SIGNAL_OBJECT_ADDED], 0, object);
-    schedule_emit_objects_changed (self);
+    self->changed = TRUE;
   }
 }
 
+/* caller must also call wp_object_manager_maybe_objects_changed() after */
 static void
 wp_object_manager_rm_object (WpObjectManager * self, gpointer object)
 {
@@ -646,7 +699,7 @@ wp_object_manager_rm_object (WpObjectManager * self, gpointer object)
   if (g_ptr_array_find (self->objects, object, &index)) {
     g_signal_emit (self, signals[SIGNAL_OBJECT_REMOVED], 0, object);
     g_ptr_array_remove_index_fast (self->objects, index);
-    schedule_emit_objects_changed (self);
+    self->changed = TRUE;
   }
 }
 
@@ -710,6 +763,7 @@ wp_registry_notify_add_object (WpRegistry *self, gpointer object)
   for (guint i = 0; i < self->object_managers->len; i++) {
     WpObjectManager *om = g_ptr_array_index (self->object_managers, i);
     wp_object_manager_add_object (om, object);
+    wp_object_manager_maybe_objects_changed (om);
   }
 }
 
@@ -719,6 +773,7 @@ wp_registry_notify_rm_object (WpRegistry *self, gpointer object)
   for (guint i = 0; i < self->object_managers->len; i++) {
     WpObjectManager *om = g_ptr_array_index (self->object_managers, i);
     wp_object_manager_rm_object (om, object);
+    wp_object_manager_maybe_objects_changed (om);
   }
 }
 
@@ -935,12 +990,17 @@ expose_tmp_globals (WpCore *core, GAsyncResult *res, WpRegistry *self)
     if (self->globals->len <= g->id)
       g_ptr_array_set_size (self->globals, g->id + 1);
     g_ptr_array_index (self->globals, g->id) = wp_global_ref (g);
+  }
 
-    /* notify object managers */
-    for (guint i = 0; i < self->object_managers->len; i++) {
-      WpObjectManager *om = g_ptr_array_index (self->object_managers, i);
+  /* notify object managers */
+  for (guint i = 0; i < self->object_managers->len; i++) {
+    WpObjectManager *om = g_ptr_array_index (self->object_managers, i);
+
+    for (guint i = 0; i < tmp_globals->len; i++) {
+      WpGlobal *g = g_ptr_array_index (tmp_globals, i);
       wp_object_manager_add_global (om, g);
     }
+    wp_object_manager_maybe_objects_changed (om);
   }
 }
 
@@ -1122,7 +1182,7 @@ wp_core_install_object_manager (WpCore * self, WpObjectManager * om)
 
   g_object_weak_ref (G_OBJECT (om), object_manager_destroyed, reg);
   g_ptr_array_add (reg->object_managers, om);
-  g_object_set (om, "core", self, NULL);
+  g_weak_ref_set (&om->core, self);
 
   /* add pre-existing objects to the object manager,
      in case it's interested in them */
@@ -1136,6 +1196,8 @@ wp_core_install_object_manager (WpCore * self, WpObjectManager * om)
     GObject *o = g_ptr_array_index (reg->objects, i);
     wp_object_manager_add_object (om, o);
   }
+
+  wp_object_manager_maybe_objects_changed (om);
 }
 
 /* WpGlobal */