wireplumber/lib/wp/object.c

/* WirePlumber
 *
 * Copyright © 2019 Collabora Ltd.
 *    @author George Kiagiadakis <george.kiagiadakis@collabora.com>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published
 * by the Free Software Foundation, either version 2.1 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
*/

#include "object.h"
#include "error.h"

typedef struct {
  GArray *iface_objects;
  GArray *iface_types;
} WpObjectPrivate;

G_DEFINE_TYPE_WITH_PRIVATE (WpObject, wp_object, G_TYPE_OBJECT);

static void
wp_object_init (WpObject * self)
{
  WpObjectPrivate *priv = wp_object_get_instance_private (self);

  priv->iface_objects = g_array_new (FALSE, FALSE, sizeof (gpointer));
  priv->iface_types = g_array_new (FALSE, FALSE, sizeof (GType));
}

static void
wp_object_finalize (GObject * obj)
{
  WpObject *self = WP_OBJECT (obj);
  WpObjectPrivate *priv = wp_object_get_instance_private (self);
  guint i;

  for (i = 0; i < priv->iface_objects->len; i++) {
    GObject *obj = g_array_index (priv->iface_objects, GObject*, i);
    wp_interface_impl_set_object (WP_INTERFACE_IMPL (obj), NULL);
    g_object_unref (obj);
  }

  g_array_free (priv->iface_objects, TRUE);
  g_array_free (priv->iface_types, TRUE);

  G_OBJECT_CLASS (wp_object_parent_class)->finalize (obj);
}

static void
wp_object_class_init (WpObjectClass * klass)
{
  GObjectClass *object_class = (GObjectClass *) klass;
  object_class->finalize = wp_object_finalize;
}

/**
 * wp_object_implements_interface: (method)
 * @self: the object
 * @interface: an interface type
 *
 * Returns: whether the interface is implemented in this object or not
 */
gboolean
wp_object_implements_interface (WpObject * self, GType interface)
{
  WpObjectPrivate *priv = wp_object_get_instance_private (self);
  guint i;

  g_return_val_if_fail (WP_IS_OBJECT (self), FALSE);

  for (i = 0; i < priv->iface_types->len; i++) {
    GType t = g_array_index (priv->iface_types, GType, i);
    if (t == interface)
      return TRUE;
  }

  return FALSE;
}

/**
 * wp_object_get_interface: (method)
 * @self: the object
 * @interface: an interface type
 *
 * Returns: (nullable) (transfer full): the object implementing @interface
 */
GObject *
wp_object_get_interface (WpObject * self, GType interface)
{
  WpObjectPrivate *priv = wp_object_get_instance_private (self);
  guint i;

  g_return_val_if_fail (WP_IS_OBJECT (self), FALSE);

  for (i = 0; i < priv->iface_objects->len; i++) {
    GObject *obj = g_array_index (priv->iface_objects, GObject*, i);
    if (g_type_is_a (G_TYPE_FROM_INSTANCE (obj), interface))
      return g_object_ref (obj);
  }

  return NULL;
}

/**
 * wp_object_list_interfaces: (method)
 * @self: the object
 * @n_interfaces: (out): the number of elements in the returned array
 *
 * Returns: (array length=n_interfaces) (transfer none): the interface types
 *   that are implemented in this object
 */
GType *
wp_object_list_interfaces (WpObject * self, guint * n_interfaces)
{
  WpObjectPrivate *priv = wp_object_get_instance_private (self);

  g_return_val_if_fail (WP_IS_OBJECT (self), NULL);

  *n_interfaces = priv->iface_types->len;
  return (GType *) priv->iface_types->data;
}

/**
 * wp_object_attach_interface_impl: (method)
 * @self: the object
 * @impl: (transfer none): the interface implementation
 * @error: (out): a GError to return on failure
 *
 * Returns: TRUE one success, FALSE on error
 */
gboolean
wp_object_attach_interface_impl (WpObject * self, WpInterfaceImpl * impl,
    GError ** error)
{
  WpObjectPrivate *priv = wp_object_get_instance_private (self);
  GType *new_ifaces;
  GType *prerequisites;
  guint n_new_ifaces;
  guint n_prerequisites, n_satisfied = 0;
  guint i, j;

  g_return_val_if_fail (WP_IS_OBJECT (self), FALSE);
  g_return_val_if_fail (WP_IS_INTERFACE_IMPL (impl), FALSE);

  new_ifaces = g_type_interfaces (G_TYPE_FROM_INSTANCE (impl),
      &n_new_ifaces);
  prerequisites = wp_interface_impl_get_prerequisites (impl, &n_prerequisites);

  for (i = 0; i < priv->iface_types->len; i++) {
    GType t = g_array_index (priv->iface_types, GType, i);

    for (j = 0; j < n_prerequisites; j++) {
      if (prerequisites[j] == t)
        n_satisfied++;
    }

    for (j = 0; j < n_new_ifaces; j++) {
      if (new_ifaces[j] == t) {
        g_set_error (error, WP_DOMAIN_LIBRARY, WP_LIBRARY_ERROR_INVARIANT,
            "Interface %s is already provided on object %p",
            g_type_name (t), self);
        return FALSE;
      }
    }
  }

  if (n_satisfied != n_prerequisites) {
    g_set_error (error, WP_DOMAIN_LIBRARY, WP_LIBRARY_ERROR_INVARIANT,
        "Interface implementation %p has unsatisfied requirements", impl);
    return FALSE;
  }

  g_object_ref (impl);
  g_array_append_val (priv->iface_objects, impl);
  g_array_append_vals (priv->iface_types, new_ifaces, n_new_ifaces);
  wp_interface_impl_set_object (impl, G_OBJECT (self));
  return TRUE;
}