Registers a fallback handler for a given subsection of the object hierarchy.

Summary:
Goal of this patch is cover in Eldbus library function dbus_connection_register_fallback.
http://dbus.freedesktop.org/doc/api/html/group__DBusConnection.html#gac4473b37bfa74ccf7459959d27e7bc59

Reviewers: stanluk, raster

Reviewed By: raster

Differential Revision: https://phab.enlightenment.org/D479

src/lib/eldbus/eldbus_private_types.h

@@ -146,6 +146,8 @@ struct _Eldbus_Service_Object
    Eldbus_Service_Object *parent;
    Eina_Inlist *children;
 
+   Eina_Bool fallback :1; /* Fallback mechanism flag */
+
    //ObjectManager data
    Eldbus_Service_Interface *objmanager;
    Eina_List *iface_added;

src/lib/eldbus/eldbus_service.c

@@ -647,7 +647,7 @@ _eldbus_service_object_parent_find(Eldbus_Service_Object *obj)
 }
 
 static Eldbus_Service_Object *
-_eldbus_service_object_add(Eldbus_Connection *conn, const char *path)
+_eldbus_service_object_add(Eldbus_Connection *conn, const char *path, Eina_Bool fallback)
 {
    Eldbus_Service_Object *obj, *rootobj;
    Eina_Inlist *safe;
@@ -656,8 +656,9 @@ _eldbus_service_object_add(Eldbus_Connection *conn, const char *path)
    obj = calloc(1, sizeof(Eldbus_Service_Object));
    EINA_SAFETY_ON_NULL_RETURN_VAL(obj, NULL);
 
-   if (!dbus_connection_register_object_path(conn->dbus_conn, path, &vtable,
-                                             obj))
+   obj->fallback = fallback;
+   if ((fallback && !dbus_connection_register_fallback(conn->dbus_conn, path, &vtable, obj)) ||
+      (!fallback && !dbus_connection_register_object_path(conn->dbus_conn, path, &vtable, obj)))
      {
         free(obj);
         return NULL;
@@ -668,6 +669,8 @@ _eldbus_service_object_add(Eldbus_Connection *conn, const char *path)
    obj->interfaces = eina_hash_string_superfast_new(NULL);
    eldbus_connection_free_cb_add(conn, _on_connection_free, obj);
 
+   if (obj->fallback) return obj;
+
    eina_hash_add(obj->interfaces, introspectable->name, introspectable);
    eina_hash_add(obj->interfaces, properties_iface->name, properties_iface);
 
@@ -924,8 +927,8 @@ fail_signature:
    return NULL;
 }
 
-EAPI Eldbus_Service_Interface *
-eldbus_service_interface_register(Eldbus_Connection *conn, const char *path, const Eldbus_Service_Interface_Desc *desc)
+static Eldbus_Service_Interface *
+_eldbus_service_interface_register(Eldbus_Connection *conn, const char *path, const Eldbus_Service_Interface_Desc *desc, Eina_Bool fallback)
 {
    Eldbus_Service_Object *obj;
    Eldbus_Service_Interface *iface;
@@ -950,7 +953,7 @@ eldbus_service_interface_register(Eldbus_Connection *conn, const char *path, con
      return NULL;
 
    if (!obj)
-     obj = _eldbus_service_object_add(conn, path);
+     obj = _eldbus_service_object_add(conn, path, fallback);
    else
      obj->introspection_dirty = EINA_TRUE;
    EINA_SAFETY_ON_NULL_GOTO(obj, fail);
@@ -982,6 +985,18 @@ fail:
    return NULL;
 }
 
+EAPI Eldbus_Service_Interface *
+eldbus_service_interface_register(Eldbus_Connection *conn, const char *path, const Eldbus_Service_Interface_Desc *desc)
+{
+   return _eldbus_service_interface_register(conn, path, desc, EINA_FALSE);
+}
+
+EAPI Eldbus_Service_Interface *
+eldbus_service_interface_fallback_register(Eldbus_Connection *conn, const char *path, const Eldbus_Service_Interface_Desc *desc)
+{
+   return _eldbus_service_interface_register(conn, path, desc, EINA_TRUE);
+}
+
 static Eina_Bool
 _idler_propschanged(void *data)
 {
@@ -1275,11 +1290,18 @@ _object_handler(DBusConnection *dbus_conn EINA_UNUSED, DBusMessage *msg, void *u
    const Eldbus_Method *method;
    Eldbus_Message *eldbus_msg, *reply;
    Eldbus_Connection *conn;
+   const char* fallback_path = NULL;
 
    obj = user_data;
    if (!obj) return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
    conn = obj->conn;
 
+   if (obj->fallback)
+     {
+       fallback_path = eina_stringshare_add(obj->path);
+       eina_stringshare_replace(&obj->path, dbus_message_get_path(msg));
+     }
+
    DBG("Connection@%p Got message:\n"
           "  Type: %s\n"
           "  Path: %s\n"
@@ -1331,6 +1353,12 @@ _object_handler(DBusConnection *dbus_conn EINA_UNUSED, DBusMessage *msg, void *u
    eldbus_connection_unref(conn);
    eldbus_shutdown();
 
+   if (obj->fallback)
+     {
+        eina_stringshare_replace(&obj->path, fallback_path);
+        eina_stringshare_del(fallback_path);
+     }
+
    return DBUS_HANDLER_RESULT_HANDLED;
 }
 

src/lib/eldbus/eldbus_service.h

@@ -108,6 +108,21 @@ typedef struct _Eldbus_Service_Interface_Desc
  */
 EAPI Eldbus_Service_Interface *eldbus_service_interface_register(Eldbus_Connection *conn, const char *path, const Eldbus_Service_Interface_Desc *desc) EINA_ARG_NONNULL(1, 2, 3);
 
+/**
+ * @brief Register a fallback interface handler for a given subsection of the object hierarchy.
+ * Note: Use eldbus_service_interface_unregister() to unregister a interface.
+ * @param conn where the interface should listen
+ * @param path a '/' delimited string of path elements
+ * @param desc description of interface
+ * @see eldbus_service_interface_unregister()
+ *
+ * @since 1.9
+ *
+ * @return Interface
+ */
+EAPI Eldbus_Service_Interface *
+eldbus_service_interface_fallback_register(Eldbus_Connection *conn, const char *path, const Eldbus_Service_Interface_Desc *desc) EINA_ARG_NONNULL(1, 2, 3);
+
 /**
  * @brief Unregister a interface.
  * Note: This doesn't unregister the object path if interface count reaches 0.