X-Git-Url: http://git.efficios.com/?a=blobdiff_plain;f=include%2Fbabeltrace%2Fobject-internal.h;h=9859e329d36a34565bb86daedb75762387d8cacb;hb=36712f1d9ad9269638e493ca36a50979fe4da989;hp=4bf4def69c070f3182003d5e57feae19d2ad6f2d;hpb=7c56f3cc43c4a45c87a6edd3146885d7d1976856;p=babeltrace.git

diff --git a/include/babeltrace/object-internal.h b/include/babeltrace/object-internal.h
index 4bf4def6..9859e329 100644
--- a/include/babeltrace/object-internal.h
+++ b/include/babeltrace/object-internal.h
@@ -38,8 +38,10 @@
  */
 struct bt_object {
 	struct bt_ref ref_count;
-	/* Class-specific release function. */
+	/* Class-specific, optional release function. */
 	bt_object_release_func release;
+	/* Class-specific, optional "parent is owner" notification listener. */
+	bt_object_release_func parent_is_owner_listener;
 	/* @see doc/ref-counting.md */
 	struct bt_object *parent;
 };
@@ -57,7 +59,12 @@ void bt_object_release(void *ptr)
 {
 	struct bt_object *obj = ptr;
 
-	if (obj && obj->release && !bt_object_get_ref_count(obj)) {
+#ifdef BT_LOGV
+	BT_LOGV("Releasing object: addr=%p, ref-count=%lu", ptr,
+		obj->ref_count.count);
+#endif
+
+	if (obj && obj->release && bt_object_get_ref_count(obj) == 0) {
 		obj->release(obj);
 	}
 }
@@ -66,19 +73,44 @@ static inline
 void generic_release(struct bt_object *obj)
 {
 	if (obj->parent) {
+		struct bt_object *parent = obj->parent;
+
+#ifdef BT_LOGV
+		BT_LOGV("Releasing parented object: addr=%p, ref-count=%lu, "
+			"parent-addr=%p, parent-ref-count=%lu",
+			obj, obj->ref_count.count,
+			parent, parent->ref_count.count);
+#endif
+
+		if (obj->parent_is_owner_listener) {
+			/*
+			 * Object has a chance to destroy itself here
+			 * under certain conditions and notify its
+			 * parent. At this point the parent is
+			 * guaranteed to exist because it's not put yet.
+			 */
+			obj->parent_is_owner_listener(obj);
+		}
+
 		/* The release function will be invoked by the parent. */
-		bt_put(obj->parent);
+		bt_put(parent);
 	} else {
 		bt_object_release(obj);
 	}
 }
 
 static inline
-struct bt_object *bt_object_get_parent(void *ptr)
+struct bt_object *bt_object_borrow_parent(void *ptr)
 {
 	struct bt_object *obj = ptr;
 
-	return ptr ? bt_get(obj->parent) : NULL;
+	return obj ? obj->parent : NULL;
+}
+
+static inline
+struct bt_object *bt_object_get_parent(void *ptr)
+{
+	return bt_get(bt_object_borrow_parent(ptr));
 }
 
 static inline
@@ -90,12 +122,18 @@ void bt_object_set_parent(void *child_ptr, void *parent)
 		return;
 	}
 
+#ifdef BT_LOGV
+	BT_LOGV("Setting object's parent: addr=%p, parent-addr=%p",
+		child_ptr, parent);
+#endif
+
 	/*
 	 * It is assumed that a "child" being "parented" is publicly reachable.
 	 * Therefore, a reference to its parent must be taken. The reference
 	 * to the parent will be released once the object's reference count
 	 * falls to zero.
 	 */
+	BT_PUT(child->parent);
 	child->parent = bt_get(parent);
 }
 
@@ -109,4 +147,12 @@ void bt_object_init(void *ptr, bt_object_release_func release)
 	bt_ref_init(&obj->ref_count, generic_release);
 }
 
+static inline
+void bt_object_set_parent_is_owner_listener(void *obj,
+		bt_object_release_func cb)
+{
+	assert(obj);
+	((struct bt_object *) obj)->parent_is_owner_listener = cb;
+}
+
 #endif /* BABELTRACE_OBJECT_INTERNAL_H */