TpPresenceMixin: Convert it to a GInterface

It is much easier to use, and should be introspectable

Reviewed-by: Simon McVittie <simon.mcvittie@collabora.co.uk>
Bug: https://bugs.freedesktop.org/show_bug.cgi?id=77189

12 files changed, 321 insertions, 593 deletions

diff --git a/docs/reference/telepathy-glib/telepathy-glib-sections.txt b/docs/reference/telepathy-glib/telepathy-glib-sections.txt
index 220235765..03e4559bf 100644
--- a/docs/reference/telepathy-glib/telepathy-glib-sections.txt
+++ b/docs/reference/telepathy-glib/telepathy-glib-sections.txt
@@ -1682,28 +1682,16 @@ TpPresenceStatus
 tp_presence_status_new
 tp_presence_status_free
 <TITLE>TpPresenceMixin</TITLE>
-TpPresenceMixin
-TpPresenceMixinClass
-tp_presence_mixin_class_init
-tp_presence_mixin_init
-tp_presence_mixin_finalize
+TpPresenceMixinInterface
 tp_presence_mixin_emit_presence_update
 tp_presence_mixin_emit_one_presence_update
-tp_presence_mixin_fill_contact_attributes
-<SUBSECTION Private>
-TP_PRESENCE_MIXIN_CLASS_OFFSET_QUARK
-TP_PRESENCE_MIXIN_CLASS_OFFSET
-TP_PRESENCE_MIXIN_OFFSET_QUARK
-TP_PRESENCE_MIXIN_OFFSET
-tp_presence_mixin_class_get_offset_quark
-tp_presence_mixin_get_offset_quark
-TpPresenceMixinPrivate
-TpPresenceMixinClassPrivate
-<SUBSECTION Standard>
-TP_PRESENCE_MIXIN_CLASS
-TP_PRESENCE_MIXIN
+<SUBSECTION Standard>
+TP_TYPE_PRESENCE_MIXIN
+TP_IS_PRESENCE_MIXIN
+TP_PRESENCE_MIXIN_GET_INTERFACE
 TpPresenceStatusSpecPrivate
 tp_presence_status_spec_get_type
+tp_presence_mixin_get_type
 </SECTION>
 
 <SECTION>
diff --git a/examples/cm/call/conn.c b/examples/cm/call/conn.c
index 8c7c50a33..3d1c1d3c5 100644
--- a/examples/cm/call/conn.c
+++ b/examples/cm/call/conn.c
@@ -31,8 +31,12 @@
 #include "call-manager.h"
 #include "protocol.h"
 
-G_DEFINE_TYPE (ExampleCallConnection, example_call_connection,
-    TP_TYPE_BASE_CONNECTION)
+static void init_presence (gpointer g_iface,
+    gpointer iface_data);
+
+G_DEFINE_TYPE_WITH_CODE (ExampleCallConnection, example_call_connection,
+    TP_TYPE_BASE_CONNECTION,
+    G_IMPLEMENT_INTERFACE (TP_TYPE_PRESENCE_MIXIN, init_presence))
 
 enum
 {
@@ -206,35 +210,18 @@ shut_down (TpBaseConnection *conn)
   tp_base_connection_finish_shutdown (conn);
 }
 
-static void
-constructed (GObject *object)
-{
-  void (*chain_up) (GObject *) =
-    G_OBJECT_CLASS (example_call_connection_parent_class)->constructed;
-
-  if (chain_up != NULL)
-    chain_up (object);
-
-  tp_presence_mixin_init (object,
-      G_STRUCT_OFFSET (ExampleCallConnection, presence_mixin));
-}
-
 static gboolean
-status_available (GObject *object,
+status_available (TpBaseConnection *base,
     guint index_)
 {
-  TpBaseConnection *base = TP_BASE_CONNECTION (object);
-
   return tp_base_connection_check_connected (base, NULL);
 }
 
 static TpPresenceStatus *
-get_contact_status (GObject *object,
+get_contact_status (TpBaseConnection *base,
     TpHandle contact)
 {
-  ExampleCallConnection *self =
-    EXAMPLE_CALL_CONNECTION (object);
-  TpBaseConnection *base = TP_BASE_CONNECTION (object);
+  ExampleCallConnection *self = EXAMPLE_CALL_CONNECTION (base);
   ExampleCallPresence presence;
   const gchar *message;
 
@@ -256,13 +243,11 @@ get_contact_status (GObject *object,
 }
 
 static gboolean
-set_own_status (GObject *object,
+set_own_status (TpBaseConnection *base,
     const TpPresenceStatus *status,
     GError **error)
 {
-  ExampleCallConnection *self =
-    EXAMPLE_CALL_CONNECTION (object);
-  TpBaseConnection *base = TP_BASE_CONNECTION (object);
+  ExampleCallConnection *self = EXAMPLE_CALL_CONNECTION (base);
   GHashTable *presences;
 
   if (status->index == EXAMPLE_CALL_PRESENCE_AWAY)
@@ -290,7 +275,7 @@ set_own_status (GObject *object,
   g_hash_table_insert (presences,
       GUINT_TO_POINTER (tp_base_connection_get_self_handle (base)),
       (gpointer) status);
-  tp_presence_mixin_emit_presence_update (object, presences);
+  tp_presence_mixin_emit_presence_update (base, presences);
   g_hash_table_unref (presences);
 
   if (!self->priv->away)
@@ -324,17 +309,15 @@ example_call_connection_get_possible_interfaces (void)
 }
 
 static void
-example_call_connection_fill_contact_attributes (TpBaseConnection *conn,
-    const gchar *dbus_interface,
-    TpHandle contact,
-    GVariantDict *attributes)
+init_presence (gpointer g_iface,
+    gpointer iface_data)
 {
-  if (tp_presence_mixin_fill_contact_attributes (G_OBJECT (conn),
-        dbus_interface, contact, attributes))
-    return;
+  TpPresenceMixinInterface *iface = g_iface;
 
-  ((TpBaseConnectionClass *) example_call_connection_parent_class)->
-    fill_contact_attributes (conn, dbus_interface, contact, attributes);
+  iface->status_available = status_available;
+  iface->get_contact_status = get_contact_status;
+  iface->set_own_status = set_own_status;
+  iface->statuses = presence_statuses;
 }
 
 static void
@@ -347,7 +330,6 @@ example_call_connection_class_init (
 
   object_class->get_property = get_property;
   object_class->set_property = set_property;
-  object_class->constructed = constructed;
   object_class->finalize = finalize;
   g_type_class_add_private (klass,
       sizeof (ExampleCallConnectionPrivate));
@@ -357,8 +339,6 @@ example_call_connection_class_init (
   base_class->create_channel_managers = create_channel_managers;
   base_class->start_connecting = start_connecting;
   base_class->shut_down = shut_down;
-  base_class->fill_contact_attributes =
-    example_call_connection_fill_contact_attributes;
 
   param_spec = g_param_spec_string ("account", "Account name",
       "The username of this user", NULL,
@@ -377,9 +357,4 @@ example_call_connection_class_init (
   signals[SIGNAL_AVAILABLE] = g_signal_new ("available",
       G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST, 0, NULL, NULL,
       NULL, G_TYPE_NONE, 1, G_TYPE_STRING);
-
-  tp_presence_mixin_class_init (object_class,
-      G_STRUCT_OFFSET (ExampleCallConnectionClass, presence_mixin),
-      status_available, get_contact_status, set_own_status,
-      presence_statuses);
 }
diff --git a/examples/cm/call/conn.h b/examples/cm/call/conn.h
index 56a252602..bb2404df8 100644
--- a/examples/cm/call/conn.h
+++ b/examples/cm/call/conn.h
@@ -27,14 +27,12 @@ typedef struct _ExampleCallConnectionClassPrivate
 
 struct _ExampleCallConnectionClass {
     TpBaseConnectionClass parent_class;
-    TpPresenceMixinClass presence_mixin;
 
     ExampleCallConnectionClassPrivate *priv;
 };
 
 struct _ExampleCallConnection {
     TpBaseConnection parent;
-    TpPresenceMixin presence_mixin;
 
     ExampleCallConnectionPrivate *priv;
 };
diff --git a/examples/cm/contactlist/conn.c b/examples/cm/contactlist/conn.c
index 0bcda0271..307ccdc87 100644
--- a/examples/cm/contactlist/conn.c
+++ b/examples/cm/contactlist/conn.c
@@ -22,12 +22,14 @@
 #include "protocol.h"
 
 static void init_aliasing (gpointer, gpointer);
+static void init_presence (gpointer, gpointer);
 
 G_DEFINE_TYPE_WITH_CODE (ExampleContactListConnection,
     example_contact_list_connection,
     TP_TYPE_BASE_CONNECTION,
     G_IMPLEMENT_INTERFACE (TP_TYPE_SVC_CONNECTION_INTERFACE_ALIASING1,
       init_aliasing)
+    G_IMPLEMENT_INTERFACE (TP_TYPE_PRESENCE_MIXIN, init_presence)
     )
 
 enum
@@ -175,8 +177,7 @@ presence_updated_cb (ExampleContactList *contact_list,
   status = tp_presence_status_new (
       example_contact_list_get_presence (contact_list, contact),
       NULL);
-  tp_presence_mixin_emit_one_presence_update ((GObject *) self,
-      contact, status);
+  tp_presence_mixin_emit_one_presence_update (base, contact, status);
   tp_presence_status_free (status);
 }
 
@@ -244,10 +245,6 @@ example_contact_list_connection_fill_contact_attributes (TpBaseConnection *conn,
         dbus_interface, contact, attributes))
     return;
 
-  if (tp_presence_mixin_fill_contact_attributes (G_OBJECT (conn),
-        dbus_interface, contact, attributes))
-    return;
-
   ((TpBaseConnectionClass *) example_contact_list_connection_parent_class)->
     fill_contact_attributes (conn, dbus_interface, contact, attributes);
 }
@@ -275,9 +272,6 @@ constructed (GObject *object)
   g_signal_connect (self->priv->contact_list, "presence-updated",
       G_CALLBACK (presence_updated_cb), self);
 
-  tp_presence_mixin_init (object,
-      G_STRUCT_OFFSET (ExampleContactListConnection, presence_mixin));
-
   iface = tp_svc_interface_skeleton_new (skel,
       TP_TYPE_SVC_CONNECTION_INTERFACE_ALIASING1);
   g_dbus_object_skeleton_add_interface (skel, iface);
@@ -285,21 +279,17 @@ constructed (GObject *object)
 }
 
 static gboolean
-status_available (GObject *object,
-                  guint index_)
+status_available (TpBaseConnection *base,
+    guint index_)
 {
-  TpBaseConnection *base = TP_BASE_CONNECTION (object);
-
   return tp_base_connection_check_connected (base, NULL);
 }
 
 static TpPresenceStatus *
-get_contact_status (GObject *object,
+get_contact_status (TpBaseConnection *base,
     TpHandle contact)
 {
-  ExampleContactListConnection *self =
-    EXAMPLE_CONTACT_LIST_CONNECTION (object);
-  TpBaseConnection *base = TP_BASE_CONNECTION (object);
+  ExampleContactListConnection *self = EXAMPLE_CONTACT_LIST_CONNECTION (base);
   ExampleContactListPresence presence;
 
   /* we get our own status from the connection, and everyone else's status
@@ -319,13 +309,11 @@ get_contact_status (GObject *object,
 }
 
 static gboolean
-set_own_status (GObject *object,
+set_own_status (TpBaseConnection *base,
                 const TpPresenceStatus *status,
                 GError **error)
 {
-  ExampleContactListConnection *self =
-    EXAMPLE_CONTACT_LIST_CONNECTION (object);
-  TpBaseConnection *base = TP_BASE_CONNECTION (object);
+  ExampleContactListConnection *self = EXAMPLE_CONTACT_LIST_CONNECTION (base);
   GHashTable *presences;
 
   if (status->index == EXAMPLE_CONTACT_LIST_PRESENCE_AWAY)
@@ -348,11 +336,24 @@ set_own_status (GObject *object,
   g_hash_table_insert (presences,
       GUINT_TO_POINTER (tp_base_connection_get_self_handle (base)),
       (gpointer) status);
-  tp_presence_mixin_emit_presence_update (object, presences);
+  tp_presence_mixin_emit_presence_update (base, presences);
   g_hash_table_unref (presences);
   return TRUE;
 }
 
+static void
+init_presence (gpointer g_iface,
+    gpointer iface_data)
+{
+  TpPresenceMixinInterface *iface = g_iface;
+
+  iface->status_available = status_available;
+  iface->get_contact_status = get_contact_status;
+  iface->set_own_status = set_own_status;
+  iface->statuses = example_contact_list_presence_statuses ();
+}
+
+
 static const gchar *interfaces_always_present[] = {
     TP_IFACE_CONNECTION_INTERFACE_ALIASING1,
     TP_IFACE_CONNECTION_INTERFACE_CONTACT_LIST1,
@@ -439,11 +440,6 @@ example_contact_list_connection_class_init (
   g_object_class_install_property (object_class, PROP_SIMULATION_DELAY,
       param_spec);
 
-  tp_presence_mixin_class_init (object_class,
-      G_STRUCT_OFFSET (ExampleContactListConnectionClass, presence_mixin),
-      status_available, get_contact_status, set_own_status,
-      example_contact_list_presence_statuses ());
-
   klass->properties_mixin.interfaces = prop_interfaces;
   tp_dbus_properties_mixin_class_init (object_class,
       G_STRUCT_OFFSET (ExampleContactListConnectionClass, properties_mixin));
diff --git a/examples/cm/contactlist/conn.h b/examples/cm/contactlist/conn.h
index b54524564..6bfa53a20 100644
--- a/examples/cm/contactlist/conn.h
+++ b/examples/cm/contactlist/conn.h
@@ -25,13 +25,11 @@ typedef struct _ExampleContactListConnectionPrivate
 
 struct _ExampleContactListConnectionClass {
     TpBaseConnectionClass parent_class;
-    TpPresenceMixinClass presence_mixin;
     TpDBusPropertiesMixinClass properties_mixin;
 };
 
 struct _ExampleContactListConnection {
     TpBaseConnection parent;
-    TpPresenceMixin presence_mixin;
 
     ExampleContactListConnectionPrivate *priv;
 };
diff --git a/telepathy-glib/base-connection-internal.h b/telepathy-glib/base-connection-internal.h
index 64fba2517..2c572ec77 100644
--- a/telepathy-glib/base-connection-internal.h
+++ b/telepathy-glib/base-connection-internal.h
@@ -22,10 +22,70 @@
 #ifndef __TP_BASE_CONNECTION_INTERNAL_H__
 #define __TP_BASE_CONNECTION_INTERNAL_H__
 
+#include <telepathy-glib/_gdbus/Connection.h>
+#include <telepathy-glib/_gdbus/Connection_Interface_Presence1.h>
+#include <telepathy-glib/_gdbus/Connection_Interface_Requests.h>
+
 #include <telepathy-glib/base-connection.h>
 
 G_BEGIN_DECLS
 
+struct _TpBaseConnectionPrivate
+{
+  gchar *bus_name;
+  gchar *object_path;
+
+  TpConnectionStatus status;
+
+  TpHandle self_handle;
+  const gchar *self_id;
+
+  /* Telepathy properties */
+  gchar *protocol;
+
+  /* if TRUE, the object has gone away */
+  gboolean dispose_has_run;
+  /* array of (TpChannelManager *) */
+  GPtrArray *channel_managers;
+  /* array of reffed (TpChannelManagerRequest *) */
+  GPtrArray *channel_requests;
+
+  TpHandleRepoIface *handles[TP_NUM_ENTITY_TYPES];
+
+  /* Created in constructed, this is an array of static strings which
+   * represent the interfaces on this connection.
+   *
+   * Note that this is a GArray of gchar*, not a GPtrArray,
+   * so that we can use GArray's convenient auto-null-termination. */
+  GArray *interfaces;
+
+  /* Array of GDBusMethodInvocation * representing Disconnect calls.
+   * If NULL and we are in a state != DISCONNECTED, then we have not started
+   * shutting down yet.
+   * If NULL and we are in state DISCONNECTED, then we have finished shutting
+   * down.
+   * If not NULL, we are trying to shut down (and must be in state
+   * DISCONNECTED). */
+  GPtrArray *disconnect_requests;
+
+  GDBusConnection *dbus_connection;
+  /* TRUE after constructor() returns */
+  gboolean been_constructed;
+  /* TRUE if on D-Bus */
+  gboolean been_registered;
+
+  /* g_strdup (unique name) => owned ClientData struct */
+  GHashTable *clients;
+  /* GQuark iface => number of clients interested */
+  GHashTable *interests;
+
+  gchar *account_path_suffix;
+
+  _TpGDBusConnection *connection_skeleton;
+  _TpGDBusConnectionInterfaceRequests *requests_skeleton;
+  _TpGDBusConnectionInterfacePresence1 *presence_skeleton;
+};
+
 void _tp_base_connection_set_handle_repo (TpBaseConnection *self,
     TpEntityType entity_type,
     TpHandleRepoIface *handle_repo);
@@ -39,6 +99,13 @@ GVariant *_tp_base_connection_dup_contact_attributes_hash (
     const gchar * const *interfaces,
     const gchar * const *assumed_interfaces);
 
+/* TpPresenceMixin */
+void _tp_presence_mixin_init (TpBaseConnection *self);
+gboolean _tp_presence_mixin_fill_contact_attributes (TpBaseConnection *self,
+    const gchar *dbus_interface,
+    TpHandle contact,
+    GVariantDict *attributes);
+
 G_END_DECLS
 
 #endif
diff --git a/telepathy-glib/base-connection.c b/telepathy-glib/base-connection.c
index 886cb74bc..9ac6fbe63 100644
--- a/telepathy-glib/base-connection.c
+++ b/telepathy-glib/base-connection.c
@@ -217,9 +217,6 @@
 #include <telepathy-glib/util.h>
 #include <telepathy-glib/value-array.h>
 
-#include <telepathy-glib/_gdbus/Connection.h>
-#include <telepathy-glib/_gdbus/Connection_Interface_Requests.h>
-
 #define DEBUG_FLAG TP_DEBUG_CONNECTION
 #include "telepathy-glib/debug-internal.h"
 #include "telepathy-glib/variant-util-internal.h"
@@ -277,54 +274,6 @@ channel_request_cancel (gpointer data,
   _tp_channel_manager_request_cancel (request);
 }
 
-struct _TpBaseConnectionPrivate
-{
-  gchar *bus_name;
-  gchar *object_path;
-
-  TpConnectionStatus status;
-
-  TpHandle self_handle;
-  const gchar *self_id;
-
-  /* Telepathy properties */
-  gchar *protocol;
-
-  /* if TRUE, the object has gone away */
-  gboolean dispose_has_run;
-  /* array of (TpChannelManager *) */
-  GPtrArray *channel_managers;
-  /* array of reffed (TpChannelManagerRequest *) */
-  GPtrArray *channel_requests;
-
-  TpHandleRepoIface *handles[TP_NUM_ENTITY_TYPES];
-
-  /* Array of GDBusMethodInvocation * representing Disconnect calls.
-   * If NULL and we are in a state != DISCONNECTED, then we have not started
-   * shutting down yet.
-   * If NULL and we are in state DISCONNECTED, then we have finished shutting
-   * down.
-   * If not NULL, we are trying to shut down (and must be in state
-   * DISCONNECTED). */
-  GPtrArray *disconnect_requests;
-
-  GDBusConnection *dbus_connection;
-  /* TRUE after constructor() returns */
-  gboolean been_constructed;
-  /* TRUE if on D-Bus */
-  gboolean been_registered;
-
-  /* g_strdup (unique name) => owned ClientData struct */
-  GHashTable *clients;
-  /* GQuark iface => number of clients interested */
-  GHashTable *interests;
-
-  gchar *account_path_suffix;
-
-  _TpGDBusConnection *connection_skeleton;
-  _TpGDBusConnectionInterfaceRequests *requests_skeleton;
-};
-
 typedef struct
 {
   /* GQuark iface => count */
@@ -495,6 +444,7 @@ tp_base_connection_dispose (GObject *object)
 
   g_clear_object (&self->priv->connection_skeleton);
   g_clear_object (&self->priv->requests_skeleton);
+  g_clear_object (&self->priv->presence_skeleton);
 
   if (G_OBJECT_CLASS (tp_base_connection_parent_class)->dispose)
     G_OBJECT_CLASS (tp_base_connection_parent_class)->dispose (object);
@@ -823,6 +773,11 @@ tp_base_connection_constructed (GObject *object)
       G_CALLBACK (tp_base_connection_interface_changed_cb),
       GINT_TO_POINTER (-1));
 
+  if (TP_IS_PRESENCE_MIXIN (self))
+    {
+      _tp_presence_mixin_init (self);
+    }
+
   /* We don't have any interfaces yet (except for Connection and Requests)
    * so it's OK that the default for _TpGDBusConnection:interfaces is NULL. */
 }
@@ -971,6 +926,10 @@ _tp_base_connection_fill_contact_attributes (TpBaseConnection *self,
 {
   const gchar *tmp;
 
+  if (_tp_presence_mixin_fill_contact_attributes (self, dbus_interface, contact,
+          attributes))
+    return;
+
   if (tp_strdiff (dbus_interface, TP_IFACE_CONNECTION))
     {
       DEBUG ("contact #%u: interface '%s' unhandled", contact, dbus_interface);
@@ -1067,7 +1026,7 @@ tp_base_connection_class_init (TpBaseConnectionClass *klass)
    *
    * If this property is %NULL or omitted during construction, the object will
    * automatically attempt to connect to the session bus with
-   * g_bus_get_sync() just after it is constructed; if this fails, this
+   * g_bus_get_sync() just after it is ; if this fails, this
    * property will remain %NULL, and tp_base_connection_register() will fail.
    *
    * Since: 0.99.10
diff --git a/telepathy-glib/presence-mixin.c b/telepathy-glib/presence-mixin.c
index 6720eab4e..792b0d224 100644
--- a/telepathy-glib/presence-mixin.c
+++ b/telepathy-glib/presence-mixin.c
@@ -20,53 +20,14 @@
 
 /**
  * SECTION:presence-mixin
- * @title: TpPresenceMixin
- * @short_description: a mixin implementation of the Presence connection
- *  interface
- *
- * This mixin can be added to a #TpBaseConnection subclass to implement the
- * Presence interface.
- *
- * To use the presence mixin, include a #TpPresenceMixinClass somewhere in your
- * class structure and a #TpPresenceMixin somewhere in your instance structure,
- * and call tp_presence_mixin_class_init() from your class_init function,
- * tp_presence_mixin_init() from your init function or constructor, and
- * tp_presence_mixin_finalize() from your dispose or finalize function.
- *
- * <section>
- * <title>Implementing Presence</title>
- * <para>
- *   Since 0.7.13 this mixin supports the entire Presence interface.
- *   You can implement #TpSvcConnectionInterfacePresence1 as follows:
- *   <itemizedlist>
- *     <listitem>
- *       <para>in the #TpBaseConnectionClass.fill_contact_attributes
- *       implementation, call tp_presence_mixin_fill_contact_attributes()
- *       and do not chain up if it returns %TRUE:
- *       </para>
- * |[
- * // ...
- * if (!tp_strdiff (dbus_interface, MY_IFACE_CONNECTION_INTERFACE_HATS))
- *   {
- *     // ... fill in Hats attributes ...
- *     return;
- *   }
- *
- * if (tp_presence_mixin_fill_contact_attributes (G_OBJECT (self),
- *         dbus_interface, contact, attributes))
- *   {
- *     return;
- *   }
- *
- * ((TpBaseConnectionClass *) my_connection_parent_class)->
- *     fill_contact_attributes (self, dbus_interface, contact, attributes);
- * ]|
- *      </listitem>
- *      </itemizedlist>
- *    </para>
- * </section>
- *
- * Since: 0.5.13
+ * @title: TpPresenceMixinInterface
+ * @short_description: an interface that can be implemented on #TpBaseConnection
+ *  subclasses to add support for presence.
+ *
+ * #TpBaseConnection subclasses can implement this interface to implement the
+ * corresponding DBus interface.
+ *
+ * Since: 0.UNRELEASED
  */
 
 /**
@@ -98,17 +59,15 @@
 
 /**
  * TpPresenceMixinStatusAvailableFunc:
- * @obj: An instance of a #TpBaseConnection subclass implementing the presence
- *  interface with this mixin
+ * @self: A #TpBaseConnection implemeting #TpPresenceMixinInterface
  * @which: An index into the array of #TpPresenceStatusSpec provided to
  *  tp_presence_mixin_class_init()
  *
  * Signature of a callback to be used to determine if a given presence
- * status can be set on the connection. Most users of this mixin do not need to
- * supply an implementation of this callback: the value of
+ * status can be set on the connection. Most users of this interface do not need
+ * to supply an implementation of this callback: the value of
  * #TpPresenceStatusSpec.self is enough to determine whether this is a
- * user-settable presence, so %NULL should be passed to
- * tp_presence_mixin_class_init() for this callback.
+ * user-settable presence.
  *
  * One place where this callback may be needed is on XMPP: not all server
  * implementation support the user becoming invisible. So an XMPP
@@ -123,7 +82,7 @@
 
 /**
  * TpPresenceMixinGetContactStatusFunc:
- * @obj: An object with this mixin.
+ * @self: A #TpBaseConnection implemeting #TpPresenceMixinInterface
  * @contact: A #TpHandle of type %TP_ENTITY_TYPE_CONTACT
  *
  * Return the contact's status
@@ -133,7 +92,7 @@
 
 /**
  * TpPresenceMixinSetOwnStatusFunc:
- * @obj: An object with this mixin.
+ * @self: A #TpBaseConnection implemeting #TpPresenceMixinInterface
  * @status: The status to set, or NULL for whatever the protocol defines as a
  *  "default" status
  * @error: Used to return a Telepathy D-Bus error if %FALSE is returned
@@ -151,7 +110,7 @@
 
 /**
  * TpPresenceMixinGetMaximumStatusMessageLengthFunc:
- * @obj: An object with this mixin.
+ * @self: A #TpBaseConnection implemeting #TpPresenceMixinInterface
  *
  * Signature of a callback used to determine the maximum length of status
  * messages. If this callback is provided and returns non-zero, the
@@ -164,46 +123,24 @@
  */
 
 /**
- * TpPresenceMixinClass:
- * @status_available: The status-available function that was passed to
- *  tp_presence_mixin_class_init()
- * @get_contact_status: The get-contact-status function that was passed to
- *  tp_presence_mixin_class_init()
- * @set_own_status: The set-own-status function that was passed to
- *  tp_presence_mixin_class_init()
- * @statuses: The presence statuses array that was passed to
- *  tp_presence_mixin_class_init()
+ * TpPresenceMixinInterface:
+ * @parent: the parent interface
+ * @status_available: A callback to be used to determine if a given presence
+ *  status can be set on a particular connection. Should usually be %NULL, to
+ *  consider all statuses with #TpPresenceStatusSpec.self set to %TRUE to be
+ *  settable.
+ * @get_contact_status: A callback to be used get the current presence status
+ *  for contacts. This is used in implementations of various D-Bus methods and
+ *  hence must be provided.
+ * @set_own_status: A callback to be used to commit changes to the user's own
+ *  presence status to the server. This is used in implementations of various
+ *  D-Bus methods and hence must be provided.
  * @get_maximum_status_message_length: The callback used to discover the
- *  the limit for status messages length, if any. Since: 0.14.5
- *
- * Structure to be included in the class structure of objects that
- * use this mixin. Initialize it with tp_presence_mixin_class_init().
- *
- * If the protocol imposes a limit on the length of status messages, one should
- * implement @get_maximum_status_message_length. If this callback is not
- * implemented, it is assumed that there is no limit. The callback function
- * should be set after calling tp_presence_mixin_class_init(), like so:
- *
- * |[
- * TpPresenceMixinClass *mixin_class;
- *
- * tp_presence_mixin_class_init ((GObjectClass *) klass,
- *     G_STRUCT_OFFSET (SomeObjectClass, presence_mixin));
- * mixin_class = TP_PRESENCE_MIXIN_CLASS (klass);
- * mixin_class->get_maximum_status_message_length =
- *     some_object_get_maximum_status_message_length;
- * ]|
- *
- * All other fields should be considered read-only.
- */
-
-/**
- * TpPresenceMixin:
- *
- * Structure to be included in the instance structure of objects that
- * use this mixin. Initialize it with tp_presence_mixin_init().
+ *  the limit for status messages length, if any.
+ * @statuses: An array of #TpPresenceStatusSpec structures representing all
+ *  presence statuses supported by the protocol, terminated by a NULL name.
  *
- * There are no public fields.
+ * The interface vtable for a %TP_TYPE_PRESENCE_MIXIN.
  */
 
 #include "config.h"
@@ -213,8 +150,6 @@
 #include <dbus/dbus-glib.h>
 #include <string.h>
 
-#include <telepathy-glib/_gdbus/Connection_Interface_Presence1.h>
-
 #include <telepathy-glib/base-connection.h>
 #include <telepathy-glib/dbus-properties-mixin.h>
 #include <telepathy-glib/enums.h>
@@ -228,6 +163,7 @@
 #define DEBUG_FLAG TP_DEBUG_PRESENCE
 
 #include "debug-internal.h"
+#include "base-connection-internal.h"
 
 struct _TpPresenceMixinPrivate
 {
@@ -283,110 +219,57 @@ tp_presence_status_free (TpPresenceStatus *status)
   g_slice_free (TpPresenceStatus, status);
 }
 
+G_DEFINE_INTERFACE (TpPresenceMixin, tp_presence_mixin, TP_TYPE_BASE_CONNECTION)
 
-/**
- * tp_presence_mixin_class_get_offset_quark: (skip)
- *
- * <!--no documentation beyond Returns: needed-->
- *
- * Returns: the quark used for storing mixin offset on a GObjectClass
- */
-GQuark
-tp_presence_mixin_class_get_offset_quark ()
+static void update_statuses_property (TpBaseConnection *self);
+static void update_max_status_message_len_property (TpBaseConnection *self);
+static gboolean tp_presence_mixin_set_presence (
+    _TpGDBusConnectionInterfacePresence1 *skeleton,
+    GDBusMethodInvocation *context,
+    const gchar *status,
+    const gchar *message,
+    TpBaseConnection *self);
+
+static void
+tp_presence_mixin_default_init (TpPresenceMixinInterface *iface)
 {
-  static GQuark offset_quark = 0;
-  if (!offset_quark)
-    offset_quark = g_quark_from_static_string ("TpPresenceMixinClassOffsetQuark");
-  return offset_quark;
 }
 
-/**
- * tp_presence_mixin_get_offset_quark: (skip)
- *
- * <!--no documentation beyond Returns: needed-->
- *
- * Returns: the quark used for storing mixin offset on a GObject
- */
-GQuark
-tp_presence_mixin_get_offset_quark ()
+static void
+connection_status_changed_cb (TpBaseConnection *self,
+    TpConnectionStatus status,
+    TpConnectionStatusReason reason,
+    gpointer user_data)
 {
-  static GQuark offset_quark = 0;
-  if (!offset_quark)
-    offset_quark = g_quark_from_static_string ("TpPresenceMixinOffsetQuark");
-  return offset_quark;
+  if (status == TP_CONNECTION_STATUS_CONNECTED)
+    {
+      update_statuses_property (self);
+      update_max_status_message_len_property (self);
+    }
 }
 
-/**
- * tp_presence_mixin_class_init: (skip)
- * @obj_cls: The class of the implementation that uses this mixin
- * @offset: The byte offset of the TpPresenceMixinClass within the class
- * structure
- * @status_available: A callback to be used to determine if a given presence
- *  status can be set on a particular connection. Should usually be %NULL, to
- *  consider all statuses with #TpPresenceStatusSpec.self set to %TRUE to be
- *  settable.
- * @get_contact_status: A callback to be used get the current presence status
- *  for contacts. This is used in implementations of various D-Bus methods and
- *  hence must be provided.
- * @set_own_status: A callback to be used to commit changes to the user's own
- *  presence status to the server. This is used in implementations of various
- *  D-Bus methods and hence must be provided.
- * @statuses: An array of #TpPresenceStatusSpec structures representing all
- *  presence statuses supported by the protocol, terminated by a NULL name.
- *
- * Initialize the presence mixin. Should be called from the implementation's
- * class_init function like so:
- *
- * <informalexample><programlisting>
- * tp_presence_mixin_class_init ((GObjectClass *) klass,
- *                               G_STRUCT_OFFSET (SomeObjectClass,
- *                                                presence_mixin));
- * </programlisting></informalexample>
- */
-
 void
-tp_presence_mixin_class_init (GObjectClass *obj_cls,
-                              glong offset,
-                              TpPresenceMixinStatusAvailableFunc status_available,
-                              TpPresenceMixinGetContactStatusFunc get_contact_status,
-                              TpPresenceMixinSetOwnStatusFunc set_own_status,
-                              const TpPresenceStatusSpec *statuses)
+_tp_presence_mixin_init (TpBaseConnection *self)
 {
-  TpPresenceMixinClass *mixin_cls;
+  TpPresenceMixinInterface *iface = TP_PRESENCE_MIXIN_GET_INTERFACE (self);
   guint i;
 
-  DEBUG ("called.");
-
-  g_assert (get_contact_status != NULL);
-  g_assert (set_own_status != NULL);
-  g_assert (statuses != NULL);
+  g_assert (iface->get_contact_status != NULL);
+  g_assert (iface->set_own_status != NULL);
+  g_assert (iface->statuses != NULL);
 
-  g_assert (G_IS_OBJECT_CLASS (obj_cls));
-
-  g_type_set_qdata (G_OBJECT_CLASS_TYPE (obj_cls),
-      TP_PRESENCE_MIXIN_CLASS_OFFSET_QUARK,
-      GINT_TO_POINTER (offset));
-
-  mixin_cls = TP_PRESENCE_MIXIN_CLASS (obj_cls);
-
-  mixin_cls->status_available = status_available;
-  mixin_cls->get_contact_status = get_contact_status;
-  mixin_cls->set_own_status = set_own_status;
-  mixin_cls->statuses = statuses;
-  mixin_cls->get_maximum_status_message_length = NULL;
-
-  for (i = 0; statuses[i].name != NULL; i++)
+  for (i = 0; iface->statuses[i].name != NULL; i++)
     {
-      if (statuses[i].self)
+      if (iface->statuses[i].self)
         {
-          switch (statuses[i].presence_type)
+          switch (iface->statuses[i].presence_type)
             {
             case TP_CONNECTION_PRESENCE_TYPE_OFFLINE:
             case TP_CONNECTION_PRESENCE_TYPE_UNKNOWN:
             case TP_CONNECTION_PRESENCE_TYPE_ERROR:
               WARNING ("Status \"%s\" of type %u should not be available "
-                  "to set on yourself", statuses[i].name,
-                  statuses[i].presence_type);
+                  "to set on yourself", iface->statuses[i].name,
+                  iface->statuses[i].presence_type);
               break;
 
             default:
@@ -394,99 +277,26 @@ tp_presence_mixin_class_init (GObjectClass *obj_cls,
             }
         }
     }
-}
-
-static void update_statuses_property (TpPresenceMixin *self,
-    GObject *object);
-static void update_max_status_message_len_property (TpPresenceMixin *self,
-    GObject *object);
-static gboolean tp_presence_mixin_set_presence (
-    _TpGDBusConnectionInterfacePresence1 *skeleton,
-    GDBusMethodInvocation *context,
-    const gchar *status,
-    const gchar *message,
-    GObject *obj);
-
-static void
-connection_status_changed_cb (GObject *object,
-    TpConnectionStatus status,
-    TpConnectionStatusReason reason,
-    TpPresenceMixin *self)
-{
-  if (status == TP_CONNECTION_STATUS_CONNECTED)
-    {
-      update_statuses_property (self, object);
-      update_max_status_message_len_property (self, object);
-    }
-}
-
-/**
- * tp_presence_mixin_init: (skip)
- * @obj: An instance of the implementation that uses this mixin
- * @offset: The byte offset of the TpPresenceMixin within the object structure
- *
- * Initialize the presence mixin. Should be called from the implementation's
- * instance init function like so:
- *
- * <informalexample><programlisting>
- * tp_presence_mixin_init ((GObject *) self,
- *                         G_STRUCT_OFFSET (SomeObject, presence_mixin));
- * </programlisting></informalexample>
- *
- * Since 0.99.1 @obj must be a #TpBaseConnection subclass.
- */
-void
-tp_presence_mixin_init (GObject *obj,
-                        glong offset)
-{
-  TpPresenceMixin *self;
-
-  DEBUG ("called.");
 
-  g_assert (TP_IS_BASE_CONNECTION (obj));
+  self->priv->presence_skeleton =
+      _tp_gdbus_connection_interface_presence1_skeleton_new ();
 
-  g_type_set_qdata (G_OBJECT_TYPE (obj),
-                    TP_PRESENCE_MIXIN_OFFSET_QUARK,
-                    GINT_TO_POINTER (offset));
-
-  self = TP_PRESENCE_MIXIN (obj);
-  self->priv = g_slice_new0 (TpPresenceMixinPrivate);
-
-  self->priv->skeleton = _tp_gdbus_connection_interface_presence1_skeleton_new ();
-  g_signal_connect_object (self->priv->skeleton, "handle-set-presence",
-      G_CALLBACK (tp_presence_mixin_set_presence), obj, 0);
+  g_signal_connect_object (self->priv->presence_skeleton, "handle-set-presence",
+      G_CALLBACK (tp_presence_mixin_set_presence), self, 0);
 
   /* Set the initial properties values, we'll update them once CONNECTED */
-  update_max_status_message_len_property (self, obj);
-  update_statuses_property (self, obj);
-  g_signal_connect (obj, "status-changed",
-      G_CALLBACK (connection_status_changed_cb), self);
-
-  g_dbus_object_skeleton_add_interface (G_DBUS_OBJECT_SKELETON (obj),
-      G_DBUS_INTERFACE_SKELETON (self->priv->skeleton));
-}
-
-/**
- * tp_presence_mixin_finalize: (skip)
- * @obj: An object with this mixin.
- *
- * Free resources held by the presence mixin.
- */
-void
-tp_presence_mixin_finalize (GObject *obj)
-{
-  TpPresenceMixin *self = TP_PRESENCE_MIXIN (obj);
-
-  DEBUG ("%p", obj);
+  update_max_status_message_len_property (self);
+  update_statuses_property (self);
+  g_signal_connect (self, "status-changed",
+      G_CALLBACK (connection_status_changed_cb), NULL);
 
-  g_object_unref (self->priv->skeleton);
-
-  g_slice_free (TpPresenceMixinPrivate, self->priv);
+  g_dbus_object_skeleton_add_interface (G_DBUS_OBJECT_SKELETON (self),
+      G_DBUS_INTERFACE_SKELETON (self->priv->presence_skeleton));
 }
 
 /**
  * tp_presence_mixin_emit_presence_update: (skip)
- * @obj: A connection object with this mixin
+ * @self: A #TpBaseConnection implemeting #TpPresenceMixinInterface
  * @contact_presences: A mapping of contact handles to #TpPresenceStatus
  *  structures with the presence data to emit
  *
@@ -495,33 +305,29 @@ tp_presence_mixin_finalize (GObject *obj)
  * #tp_presence_mixin_emit_one_presence_update.
  */
 void
-tp_presence_mixin_emit_presence_update (GObject *obj,
+tp_presence_mixin_emit_presence_update (TpBaseConnection *self,
                                         GHashTable *contact_statuses)
 {
-  TpPresenceMixin *self = TP_PRESENCE_MIXIN (obj);
-  TpPresenceMixinClass *mixin_cls =
-    TP_PRESENCE_MIXIN_CLASS (G_OBJECT_GET_CLASS (obj));
+  TpPresenceMixinInterface *iface = TP_PRESENCE_MIXIN_GET_INTERFACE (self);
 
   DEBUG ("called.");
 
   _tp_gdbus_connection_interface_presence1_emit_presences_changed (
-      self->priv->skeleton,
-      construct_presence_hash (mixin_cls->statuses, contact_statuses));
+      self->priv->presence_skeleton,
+      construct_presence_hash (iface->statuses, contact_statuses));
 }
 
-
 /**
- * tp_presence_mixin_emit_one_presence_update: (skip)
- * @obj: A connection object with this mixin
+ * tp_presence_mixin_emit_one_presence_update:
+ * @self: A #TpBaseConnection implemeting #TpPresenceMixinInterface
  * @handle: The handle of the contact to emit the signal for
  * @status: The new status to emit
  *
  * Emit a presence update signal for a single contact. This method is
- * just a convenience wrapper around
- * #tp_presence_mixin_emit_presence_update.
+ * just a convenience wrapper around tp_presence_mixin_emit_presence_update().
  */
 void
-tp_presence_mixin_emit_one_presence_update (GObject *obj,
+tp_presence_mixin_emit_one_presence_update (TpBaseConnection *self,
                                             TpHandle handle,
                                             const TpPresenceStatus *status)
 {
@@ -532,38 +338,38 @@ tp_presence_mixin_emit_one_presence_update (GObject *obj,
   contact_statuses = g_hash_table_new (NULL, NULL);
   g_hash_table_insert (contact_statuses, GUINT_TO_POINTER (handle),
       (gpointer) status);
-  tp_presence_mixin_emit_presence_update (obj, contact_statuses);
+  tp_presence_mixin_emit_presence_update (self, contact_statuses);
 
   g_hash_table_unref (contact_statuses);
 }
 
 static gboolean
-check_status_available (GObject *object,
-                        TpPresenceMixinClass *mixin_cls,
-                        guint i,
-                        GError **error,
-                        gboolean for_self)
+check_status_available (TpBaseConnection *self,
+    TpPresenceMixinInterface *iface,
+    guint i,
+    GError **error,
+    gboolean for_self)
 {
   if (for_self)
     {
-      if (!mixin_cls->statuses[i].self)
+      if (!iface->statuses[i].self)
         {
           g_set_error (error, TP_ERROR, TP_ERROR_INVALID_ARGUMENT,
               "cannot set status '%s' on yourself",
-              mixin_cls->statuses[i].name);
+              iface->statuses[i].name);
           return FALSE;
         }
 
       /* never allow OFFLINE, UNKNOWN or ERROR - if the CM says they're
        * OK to set on yourself, then it's wrong */
-      switch (mixin_cls->statuses[i].presence_type)
+      switch (iface->statuses[i].presence_type)
         {
         case TP_CONNECTION_PRESENCE_TYPE_OFFLINE:
         case TP_CONNECTION_PRESENCE_TYPE_UNKNOWN:
         case TP_CONNECTION_PRESENCE_TYPE_ERROR:
           g_set_error (error, TP_ERROR, TP_ERROR_INVALID_ARGUMENT,
               "cannot set offline/unknown/error status '%s' on yourself",
-              mixin_cls->statuses[i].name);
+              iface->statuses[i].name);
           return FALSE;
 
         default:
@@ -571,14 +377,13 @@ check_status_available (GObject *object,
         }
     }
 
-  if (mixin_cls->status_available
-      && !mixin_cls->status_available (object, i))
+  if (iface->status_available != NULL && !iface->status_available (self, i))
     {
       DEBUG ("requested status %s is not available",
-          mixin_cls->statuses[i].name);
+          iface->statuses[i].name);
       g_set_error (error, TP_ERROR, TP_ERROR_NOT_AVAILABLE,
           "requested status '%s' is not available on this connection",
-          mixin_cls->statuses[i].name);
+          iface->statuses[i].name);
       return FALSE;
     }
 
@@ -586,24 +391,25 @@ check_status_available (GObject *object,
 }
 
 static int
-check_for_status (GObject *object, const gchar *status, GError **error)
+check_for_status (TpBaseConnection *self,
+    const gchar *status,
+    GError **error)
 {
-  TpPresenceMixinClass *mixin_cls =
-    TP_PRESENCE_MIXIN_CLASS (G_OBJECT_GET_CLASS (object));
+  TpPresenceMixinInterface *iface = TP_PRESENCE_MIXIN_GET_INTERFACE (self);
   int i;
 
-  for (i = 0; mixin_cls->statuses[i].name != NULL; i++)
+  for (i = 0; iface->statuses[i].name != NULL; i++)
     {
-      if (!tp_strdiff (mixin_cls->statuses[i].name, status))
+      if (!tp_strdiff (iface->statuses[i].name, status))
         break;
     }
 
-  if (mixin_cls->statuses[i].name != NULL)
+  if (iface->statuses[i].name != NULL)
     {
       DEBUG ("Found status \"%s\", checking if it's available...",
           (const gchar *) status);
 
-      if (!check_status_available (object, mixin_cls, i, error, TRUE))
+      if (!check_status_available (self, iface, i, error, TRUE))
         return -1;
     }
   else
@@ -618,80 +424,66 @@ check_for_status (GObject *object, const gchar *status, GError **error)
 }
 
 static void
-update_statuses_property (TpPresenceMixin *self,
-    GObject *object)
+update_statuses_property (TpBaseConnection *self)
 {
-  TpPresenceMixinClass *mixin_cls =
-      TP_PRESENCE_MIXIN_CLASS (G_OBJECT_GET_CLASS (object));
+  TpPresenceMixinInterface *iface = TP_PRESENCE_MIXIN_GET_INTERFACE (self);
   GVariantBuilder builder;
   int i;
 
   g_variant_builder_init (&builder, G_VARIANT_TYPE ("a{s(ubb)}"));
-  for (i = 0; mixin_cls->statuses[i].name != NULL; i++)
+  for (i = 0; iface->statuses[i].name != NULL; i++)
     {
       gboolean message;
 
       /* we include statuses here even if they're not available
        * to set on yourself */
-      if (!check_status_available (object, mixin_cls, i, NULL, FALSE))
+      if (!check_status_available (self, iface, i, NULL, FALSE))
         continue;
 
       message = tp_presence_status_spec_has_message (
-          &mixin_cls->statuses[i]);
+          &iface->statuses[i]);
 
       g_variant_builder_add (&builder, "{s(ubb)}",
-          mixin_cls->statuses[i].name,
-          mixin_cls->statuses[i].presence_type,
-          mixin_cls->statuses[i].self,
+          iface->statuses[i].name,
+          iface->statuses[i].presence_type,
+          iface->statuses[i].self,
           message);
    }
 
-  _tp_gdbus_connection_interface_presence1_set_statuses (self->priv->skeleton,
+  _tp_gdbus_connection_interface_presence1_set_statuses (
+      self->priv->presence_skeleton,
       g_variant_builder_end (&builder));
 }
 
 static void
-update_max_status_message_len_property (TpPresenceMixin *self,
-    GObject *object)
+update_max_status_message_len_property (TpBaseConnection *self)
 {
-  TpPresenceMixinClass *mixin_cls =
-      TP_PRESENCE_MIXIN_CLASS (G_OBJECT_GET_CLASS (object));
+  TpPresenceMixinInterface *iface = TP_PRESENCE_MIXIN_GET_INTERFACE (self);
   guint max_status_message_length = 0;
 
-  if (mixin_cls->get_maximum_status_message_length != NULL)
-    max_status_message_length =
-        mixin_cls->get_maximum_status_message_length (object);
+  if (iface->get_maximum_status_message_length != NULL)
+    max_status_message_length = iface->get_maximum_status_message_length (self);
 
   _tp_gdbus_connection_interface_presence1_set_maximum_status_message_length (
-      self->priv->skeleton, max_status_message_length);
+      self->priv->presence_skeleton, max_status_message_length);
 }
 
-/*
- * tp_presence_mixin_set_presence:
- *
- * Implements D-Bus method SetPresence
- * on interface im.telepathy.v1.Connection.Interface.Presence
- *
- * @context: The D-Bus invocation context to use to return values
- *           or throw an error.
- */
 static gboolean
 tp_presence_mixin_set_presence (
     _TpGDBusConnectionInterfacePresence1 *skeleton,
     GDBusMethodInvocation *context,
     const gchar *status,
     const gchar *message,
-    GObject *obj)
+    TpBaseConnection *self)
 {
-  TpPresenceMixinClass *mixin_cls =
-    TP_PRESENCE_MIXIN_CLASS (G_OBJECT_GET_CLASS (obj));
+  TpPresenceMixinInterface *iface = TP_PRESENCE_MIXIN_GET_INTERFACE (self);
   TpPresenceStatus status_to_set = { 0, };
   int s;
   GError *error = NULL;
 
   DEBUG ("called.");
 
-  s = check_for_status (obj, status, &error);
+  s = check_for_status (self, status, &error);
   if (s == -1)
     goto out;
 
@@ -701,7 +493,7 @@ tp_presence_mixin_set_presence (
   status_to_set.index = s;
   status_to_set.message = g_strdup (message);
 
-  mixin_cls->set_own_status (obj, &status_to_set, &error);
+  iface->set_own_status (self, &status_to_set, &error);
 
   g_free (status_to_set.message);
 
@@ -763,33 +555,19 @@ construct_presence_hash (const TpPresenceStatusSpec *supported_statuses,
   return g_variant_builder_end (&builder);
 }
 
-/**
- * tp_presence_mixin_fill_contact_attributes:
- * @obj: an object with a #TpPresenceMixin
- * @dbus_interface: a D-Bus interface
- * @contact: a contact
- * @attributes: used to return attributes
- *
- * If @dbus_interface is an interface that is relevant for this
- * object, fill @attributes with the attributes for @contact
- * and return %TRUE.
- *
- * Returns: %TRUE if @dbus_interface was recognised
- */
 gboolean
-tp_presence_mixin_fill_contact_attributes (GObject *obj,
+_tp_presence_mixin_fill_contact_attributes (TpBaseConnection *self,
   const gchar *dbus_interface,
   TpHandle contact,
   GVariantDict *attributes)
 {
-  TpPresenceMixinClass *mixin_cls =
-    TP_PRESENCE_MIXIN_CLASS (G_OBJECT_GET_CLASS (obj));
+  TpPresenceMixinInterface *iface = TP_PRESENCE_MIXIN_GET_INTERFACE (self);
   TpPresenceStatus *status;
 
   if (tp_strdiff (dbus_interface, TP_IFACE_CONNECTION_INTERFACE_PRESENCE1))
     return FALSE;
 
-  status = mixin_cls->get_contact_status (obj, contact);
+  status = iface->get_contact_status (self, contact);
 
   if (status == NULL)
     {
@@ -799,7 +577,7 @@ tp_presence_mixin_fill_contact_attributes (GObject *obj,
     {
       g_variant_dict_insert_value (attributes,
           TP_TOKEN_CONNECTION_INTERFACE_PRESENCE1_PRESENCE,
-          construct_presence_variant (status, mixin_cls->statuses));
+          construct_presence_variant (status, iface->statuses));
       tp_presence_status_free (status);
     }
   return TRUE;
diff --git a/telepathy-glib/presence-mixin.h b/telepathy-glib/presence-mixin.h
index ac14c0279..ed4483487 100644
--- a/telepathy-glib/presence-mixin.h
+++ b/telepathy-glib/presence-mixin.h
@@ -32,6 +32,8 @@
 
 G_BEGIN_DECLS
 
+/* -- TpPresenceStatusSpec -- */
+
 typedef struct _TpPresenceStatusSpec TpPresenceStatusSpec;
 typedef struct _TpPresenceStatusSpecPrivate TpPresenceStatusSpecPrivate;
 
@@ -78,6 +80,9 @@ TpPresenceStatusSpec *tp_presence_status_spec_copy (
 _TP_AVAILABLE_IN_1_0
 void tp_presence_status_spec_free (TpPresenceStatusSpec *self);
 
+/* -- TpPresenceStatus -- */
+
+
 typedef struct _TpPresenceStatus TpPresenceStatus;
 
 struct _TpPresenceStatus {
@@ -92,82 +97,56 @@ TpPresenceStatus *tp_presence_status_new (guint which,
     const gchar *message) G_GNUC_WARN_UNUSED_RESULT;
 void tp_presence_status_free (TpPresenceStatus *status);
 
-typedef gboolean (*TpPresenceMixinStatusAvailableFunc) (GObject *obj,
-    guint which);
+/* -- TpPresenceMixinInterface -- */
 
-typedef TpPresenceStatus *(*TpPresenceMixinGetContactStatusFunc) (GObject *obj,
-    TpHandle contact);
+#define TP_TYPE_PRESENCE_MIXIN \
+  (tp_presence_mixin_get_type ())
 
-typedef gboolean (*TpPresenceMixinSetOwnStatusFunc) (GObject *obj,
-    const TpPresenceStatus *status, GError **error);
+#define TP_IS_PRESENCE_MIXIN(obj) \
+  (G_TYPE_CHECK_INSTANCE_TYPE ((obj), \
+  TP_TYPE_PRESENCE_MIXIN))
 
-typedef guint (*TpPresenceMixinGetMaximumStatusMessageLengthFunc) (
-    GObject *obj);
+#define TP_PRESENCE_MIXIN_GET_INTERFACE(obj) \
+  (G_TYPE_INSTANCE_GET_INTERFACE ((obj), \
+  TP_TYPE_PRESENCE_MIXIN, TpPresenceMixinInterface))
 
-typedef struct _TpPresenceMixinClass TpPresenceMixinClass;
-typedef struct _TpPresenceMixinClassPrivate TpPresenceMixinClassPrivate;
-typedef struct _TpPresenceMixin TpPresenceMixin;
-typedef struct _TpPresenceMixinPrivate TpPresenceMixinPrivate;
+typedef struct _TpPresenceMixinInterface TpPresenceMixinInterface;
+/* For some reason g-i wants that name */
+typedef struct _TpPresenceMixinInterface TpPresenceMixin;
 
-struct _TpPresenceMixinClass {
-    TpPresenceMixinStatusAvailableFunc status_available;
-    TpPresenceMixinGetContactStatusFunc get_contact_status;
-    TpPresenceMixinSetOwnStatusFunc set_own_status;
+typedef gboolean (*TpPresenceMixinStatusAvailableFunc) (TpBaseConnection *self,
+    guint which);
 
-    const TpPresenceStatusSpec *statuses;
+typedef TpPresenceStatus *(*TpPresenceMixinGetContactStatusFunc) (
+    TpBaseConnection *self,
+    TpHandle contact);
 
-    /*<private>*/
-    TpPresenceMixinClassPrivate *priv;
+typedef gboolean (*TpPresenceMixinSetOwnStatusFunc) (TpBaseConnection *self,
+    const TpPresenceStatus *status,
+    GError **error);
 
-    /*<public>*/
-    TpPresenceMixinGetMaximumStatusMessageLengthFunc get_maximum_status_message_length;
+typedef guint (*TpPresenceMixinGetMaximumStatusMessageLengthFunc) (
+    TpBaseConnection *self);
 
-    /*<private>*/
-    GCallback _future[10];
-};
+struct _TpPresenceMixinInterface {
+  GTypeInterface parent;
 
-struct _TpPresenceMixin {
-  /*<private>*/
-  TpPresenceMixinPrivate *priv;
+  TpPresenceMixinStatusAvailableFunc status_available;
+  TpPresenceMixinGetContactStatusFunc get_contact_status;
+  TpPresenceMixinSetOwnStatusFunc set_own_status;
+  TpPresenceMixinGetMaximumStatusMessageLengthFunc
+      get_maximum_status_message_length;
+
+  const TpPresenceStatusSpec *statuses;
 };
 
-/* TYPE MACROS */
-#define TP_PRESENCE_MIXIN_CLASS_OFFSET_QUARK \
-  (tp_presence_mixin_class_get_offset_quark ())
-#define TP_PRESENCE_MIXIN_CLASS_OFFSET(o) \
-  tp_mixin_class_get_offset (o, TP_PRESENCE_MIXIN_CLASS_OFFSET_QUARK)
-#define TP_PRESENCE_MIXIN_CLASS(o) \
-  ((TpPresenceMixinClass *) tp_mixin_offset_cast (o, \
-    TP_PRESENCE_MIXIN_CLASS_OFFSET (o)))
-
-#define TP_PRESENCE_MIXIN_OFFSET_QUARK (tp_presence_mixin_get_offset_quark ())
-#define TP_PRESENCE_MIXIN_OFFSET(o) \
-  tp_mixin_instance_get_offset (o, TP_PRESENCE_MIXIN_OFFSET_QUARK)
-#define TP_PRESENCE_MIXIN(o) \
-  ((TpPresenceMixin *) tp_mixin_offset_cast (o, TP_PRESENCE_MIXIN_OFFSET (o)))
-
-GQuark tp_presence_mixin_class_get_offset_quark (void);
-GQuark tp_presence_mixin_get_offset_quark (void);
-
-void tp_presence_mixin_class_init (GObjectClass *obj_cls, glong offset,
-    TpPresenceMixinStatusAvailableFunc status_available,
-    TpPresenceMixinGetContactStatusFunc get_contact_status,
-    TpPresenceMixinSetOwnStatusFunc set_own_status,
-    const TpPresenceStatusSpec *statuses);
-
-void tp_presence_mixin_init (GObject *obj, glong offset);
-void tp_presence_mixin_finalize (GObject *obj);
-
-void tp_presence_mixin_emit_presence_update (GObject *obj,
-    GHashTable *contact_presences);
-void tp_presence_mixin_emit_one_presence_update (GObject *obj,
-    TpHandle handle, const TpPresenceStatus *status);
+GType tp_presence_mixin_get_type (void) G_GNUC_CONST;
 
-_TP_AVAILABLE_IN_1_0
-gboolean tp_presence_mixin_fill_contact_attributes (GObject *obj,
-  const gchar *dbus_interface,
-  TpHandle contact,
-  GVariantDict *attributes);
+void tp_presence_mixin_emit_presence_update (TpBaseConnection *self,
+    GHashTable *contact_presences);
+void tp_presence_mixin_emit_one_presence_update (TpBaseConnection *self,
+    TpHandle handle,
+    const TpPresenceStatus *status);
 
 G_END_DECLS
 
diff --git a/telepathy-glib/versions/main-1.0.abi b/telepathy-glib/versions/main-1.0.abi
index b090554be..896f53d87 100644
--- a/telepathy-glib/versions/main-1.0.abi
+++ b/telepathy-glib/versions/main-1.0.abi
@@ -988,14 +988,9 @@ tp_observe_channel_context_fail
 tp_observe_channel_context_get_requests
 tp_observe_channel_context_get_type
 tp_observe_channel_context_is_recovering
-tp_presence_mixin_class_get_offset_quark
-tp_presence_mixin_class_init
 tp_presence_mixin_emit_one_presence_update
 tp_presence_mixin_emit_presence_update
-tp_presence_mixin_fill_contact_attributes
-tp_presence_mixin_finalize
-tp_presence_mixin_get_offset_quark
-tp_presence_mixin_init
+tp_presence_mixin_get_type
 tp_presence_status_free
 tp_presence_status_new
 tp_presence_status_spec_can_set_on_self
diff --git a/tests/lib/contacts-conn.c b/tests/lib/contacts-conn.c
index a2562cb00..539c9bb8f 100644
--- a/tests/lib/contacts-conn.c
+++ b/tests/lib/contacts-conn.c
@@ -24,12 +24,14 @@
 static void init_aliasing (gpointer, gpointer);
 static void init_avatars (gpointer, gpointer);
 static void init_contact_info (gpointer, gpointer);
+static void init_presence (gpointer, gpointer);
 static void conn_avatars_properties_getter (GObject *object, GQuark interface,
     GQuark name, GValue *value, gpointer getter_data);
 
 G_DEFINE_TYPE_WITH_CODE (TpTestsContactsConnection,
     tp_tests_contacts_connection,
     TP_TESTS_TYPE_SIMPLE_CONNECTION,
+    G_IMPLEMENT_INTERFACE (TP_TYPE_PRESENCE_MIXIN, init_presence)
     G_IMPLEMENT_INTERFACE (TP_TYPE_SVC_CONNECTION_INTERFACE_ALIASING1,
       init_aliasing);
     G_IMPLEMENT_INTERFACE (TP_TYPE_SVC_CONNECTION_INTERFACE_AVATARS1,
@@ -296,10 +298,6 @@ tp_tests_contacts_connection_fill_contact_attributes (TpBaseConnection *base,
         dbus_interface, contact, attributes))
     return;
 
-  if (tp_presence_mixin_fill_contact_attributes (G_OBJECT (self),
-        dbus_interface, contact, attributes))
-    return;
-
   ((TpBaseConnectionClass *) tp_tests_contacts_connection_parent_class)->
     fill_contact_attributes (base, dbus_interface, contact, attributes);
 }
@@ -414,9 +412,6 @@ constructed (GObject *object)
 
   self->priv->list_manager = g_object_new (TP_TESTS_TYPE_CONTACT_LIST_MANAGER,
       "connection", self, NULL);
-
-  tp_presence_mixin_init (object,
-      G_STRUCT_OFFSET (TpTestsContactsConnection, presence_mixin));
 }
 
 /* Must match TpTestsContactsConnectionPresenceStatusIndex in the .h */
@@ -431,19 +426,17 @@ static const TpPresenceStatusSpec my_statuses[] = {
 };
 
 static gboolean
-my_status_available (GObject *object,
-                     guint index)
+my_status_available (TpBaseConnection *base,
+    guint index)
 {
-  TpBaseConnection *base = TP_BASE_CONNECTION (object);
-
   return tp_base_connection_check_connected (base, NULL);
 }
 
 static TpPresenceStatus *
-my_get_contact_status (GObject *object,
+my_get_contact_status (TpBaseConnection *base_conn,
     TpHandle contact)
 {
-  TpTestsContactsConnection *self = TP_TESTS_CONTACTS_CONNECTION (object);
+  TpTestsContactsConnection *self = TP_TESTS_CONTACTS_CONNECTION (base_conn);
   gpointer key = GUINT_TO_POINTER (contact);
   TpTestsContactsConnectionPresenceStatusIndex index;
   const gchar *presence_message;
@@ -457,28 +450,42 @@ my_get_contact_status (GObject *object,
 }
 
 static gboolean
-my_set_own_status (GObject *object,
+my_set_own_status (TpBaseConnection *base_conn,
                    const TpPresenceStatus *status,
                    GError **error)
 {
-  TpBaseConnection *base_conn = TP_BASE_CONNECTION (object);
   TpTestsContactsConnectionPresenceStatusIndex index = status->index;
   const gchar *message = status->message;
   TpHandle self_handle;
 
   self_handle = tp_base_connection_get_self_handle (base_conn);
-  tp_tests_contacts_connection_change_presences (TP_TESTS_CONTACTS_CONNECTION (object),
+  tp_tests_contacts_connection_change_presences (
+      TP_TESTS_CONTACTS_CONNECTION (base_conn),
       1, &self_handle, &index, &message);
 
   return TRUE;
 }
 
 static guint
-my_get_maximum_status_message_length_cb (GObject *obj)
+my_get_maximum_status_message_length_cb (TpBaseConnection *base_conn)
 {
   return 512;
 }
 
+static void
+init_presence (gpointer g_iface,
+    gpointer iface_data)
+{
+  TpPresenceMixinInterface *iface = g_iface;
+
+  iface->status_available = my_status_available;
+  iface->get_contact_status = my_get_contact_status;
+  iface->set_own_status = my_set_own_status;
+  iface->statuses = my_statuses;
+  iface->get_maximum_status_message_length =
+      my_get_maximum_status_message_length_cb;
+}
+
 static GPtrArray *
 create_channel_managers (TpBaseConnection *conn)
 {
@@ -514,7 +521,6 @@ tp_tests_contacts_connection_class_init (TpTestsContactsConnectionClass *klass)
   TpBaseConnectionClass *base_class =
       (TpBaseConnectionClass *) klass;
   GObjectClass *object_class = (GObjectClass *) klass;
-  TpPresenceMixinClass *mixin_class;
   static TpDBusPropertiesMixinPropImpl aliasing_props[] = {
     { "AliasFlags", GUINT_TO_POINTER (ALIASING_DP_ALIAS_FLAGS), NULL },
     { NULL }
@@ -547,14 +553,6 @@ tp_tests_contacts_connection_class_init (TpTestsContactsConnectionClass *klass)
   base_class->fill_contact_attributes =
     tp_tests_contacts_connection_fill_contact_attributes;
 
-  tp_presence_mixin_class_init (object_class,
-      G_STRUCT_OFFSET (TpTestsContactsConnectionClass, presence_mixin),
-      my_status_available, my_get_contact_status,
-      my_set_own_status, my_statuses);
-  mixin_class = TP_PRESENCE_MIXIN_CLASS(klass);
-  mixin_class->get_maximum_status_message_length =
-      my_get_maximum_status_message_length_cb;
-
   klass->properties_class.interfaces = prop_interfaces;
   tp_dbus_properties_mixin_class_init (object_class,
       G_STRUCT_OFFSET (TpTestsContactsConnectionClass, properties_class));
@@ -628,7 +626,7 @@ tp_tests_contacts_connection_change_presences (
             messages[i]));
     }
 
-  tp_presence_mixin_emit_presence_update ((GObject *) self,
+  tp_presence_mixin_emit_presence_update ((TpBaseConnection *) self,
       presences);
   g_hash_table_unref (presences);
 }
diff --git a/tests/lib/contacts-conn.h b/tests/lib/contacts-conn.h
index aaa826e2e..2d77c4eed 100644
--- a/tests/lib/contacts-conn.h
+++ b/tests/lib/contacts-conn.h
@@ -27,15 +27,12 @@ typedef struct _TpTestsContactsConnectionPrivate TpTestsContactsConnectionPrivat
 struct _TpTestsContactsConnectionClass {
     TpTestsSimpleConnectionClass parent_class;
 
-    TpPresenceMixinClass presence_mixin;
     TpDBusPropertiesMixinClass properties_class;
 };
 
 struct _TpTestsContactsConnection {
     TpTestsSimpleConnection parent;
 
-    TpPresenceMixin presence_mixin;
-
     TpTestsContactsConnectionPrivate *priv;
 };