From 114228f8b2c3669b5b136ce62ed1dc74e83a85f6 Mon Sep 17 00:00:00 2001
From: Thomas Haller <thaller@redhat.com>
Date: Tue, 22 Jun 2021 14:51:09 +0200
Subject: [PATCH] libnm: add NM_OBJECT_CLIENT property

We have nm_object_get_client() property that returns a reference
to the NMClient instance. This is actually useful, because if
the function returns %NULL, it means that the object was removed
from the cache.

On the other hand, the user cannot subscribe to notifications when this
happens. Well, there are otherwise pointless signals like
NM_CLIENT_DEVICE_REMOVED, which we wouldn't need if we had a general
mechanism for NMObject instances.

Add a GObject property "client", which is just that mechanism.

https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/merge_requests/902
---
 src/libnm-client-impl/nm-object.c   | 29 ++++++++++++++++++++++++++++-
 src/libnm-client-public/nm-object.h |  3 ++-
 2 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/src/libnm-client-impl/nm-object.c b/src/libnm-client-impl/nm-object.c
index 2e7de8c266..ae48853b4d 100644
--- a/src/libnm-client-impl/nm-object.c
+++ b/src/libnm-client-impl/nm-object.c
@@ -21,7 +21,7 @@
 
 /*****************************************************************************/
 
-NM_GOBJECT_PROPERTIES_DEFINE_BASE(PROP_PATH, );
+NM_GOBJECT_PROPERTIES_DEFINE_BASE(PROP_PATH, PROP_CLIENT, );
 
 typedef struct _NMObjectPrivate {
     NMClient *     client;
@@ -215,6 +215,8 @@ unregister_client(NMObject *self, NMClient *client, NMLDBusObject *dbobj)
     nm_assert(priv->client == client);
     priv->client = NULL;
 
+    _nm_client_queue_notify_object(client, self, obj_properties[PROP_CLIENT]);
+
     clear_properties(self, client);
 }
 
@@ -229,6 +231,9 @@ get_property(GObject *object, guint prop_id, GValue *value, GParamSpec *pspec)
     case PROP_PATH:
         g_value_set_string(value, nm_object_get_path(self));
         break;
+    case PROP_CLIENT:
+        g_value_set_object(value, nm_object_get_client(self));
+        break;
     default:
         G_OBJECT_WARN_INVALID_PROPERTY_ID(object, prop_id, pspec);
         break;
@@ -300,6 +305,10 @@ nm_object_class_init(NMObjectClass *klass)
      * NMObject:path:
      *
      * The D-Bus object path.
+     *
+     * The D-Bus path of an object instance never changes, even if the object
+     * gets removed from the cache. To see whether the object is still in the
+     * cache, check NMObject:client.
      **/
     obj_properties[PROP_PATH] = g_param_spec_string(NM_OBJECT_PATH,
                                                     "",
@@ -307,5 +316,23 @@ nm_object_class_init(NMObjectClass *klass)
                                                     NULL,
                                                     G_PARAM_READABLE | G_PARAM_STATIC_STRINGS);
 
+    /**
+     * NMObject:client:
+     *
+     * The NMClient instance as returned by nm_object_get_client().
+     *
+     * When an NMObject gets removed from the NMClient cache,
+     * the NMObject:path property stays unchanged, but this client
+     * instance gets reset to %NULL. You can use this property to
+     * track removal of the object from the cache.
+     *
+     * Since: 1.34
+     **/
+    obj_properties[PROP_CLIENT] = g_param_spec_object(NM_OBJECT_CLIENT,
+                                                      "",
+                                                      "",
+                                                      NM_TYPE_CLIENT,
+                                                      G_PARAM_READABLE | G_PARAM_STATIC_STRINGS);
+
     g_object_class_install_properties(object_class, _PROPERTY_ENUMS_LAST, obj_properties);
 }
diff --git a/src/libnm-client-public/nm-object.h b/src/libnm-client-public/nm-object.h
index 7b4a323294..5f41751390 100644
--- a/src/libnm-client-public/nm-object.h
+++ b/src/libnm-client-public/nm-object.h
@@ -22,7 +22,8 @@ G_BEGIN_DECLS
 #define NM_IS_OBJECT_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE((klass), NM_TYPE_OBJECT))
 #define NM_OBJECT_GET_CLASS(obj)  (G_TYPE_INSTANCE_GET_CLASS((obj), NM_TYPE_OBJECT, NMObjectClass))
 
-#define NM_OBJECT_PATH "path"
+#define NM_OBJECT_PATH   "path"
+#define NM_OBJECT_CLIENT "client"
 
 /**
  * NMObject: