Fix: relayd: rotation failure for multi-domain session

[lttng-tools.git] / src / common / trace-chunk-registry.h

diff --git a/src/common/trace-chunk-registry.h b/src/common/trace-chunk-registry.h
index b04609c32bbe55c8a519fc79b8ee0ed5ea9e1c5f..b7905cac95d55a6d3b12f8b17c14649e44c35aa6 100644 (file)
--- a/src/common/trace-chunk-registry.h
+++ b/src/common/trace-chunk-registry.h
@@ -1,18 +1,8 @@
 /*
- * Copyright (C) 2019 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
+ * Copyright (C) 2019 Jérémie Galarneau <jeremie.galarneau@efficios.com>
  *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU Lesser General Public License, version 2.1 only,
- * as published by the Free Software Foundation.
+ * SPDX-License-Identifier: LGPL-2.1-only
  *
- * 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, write to the Free Software Foundation,
- * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 #ifndef LTTNG_TRACE_CHUNK_REGISTRY_H
@@ -71,6 +61,30 @@ struct lttng_trace_chunk *lttng_trace_chunk_registry_publish_chunk(
                struct lttng_trace_chunk_registry *registry,
                uint64_t session_id, struct lttng_trace_chunk *chunk);
 
+/*
+ * Adds the `previously_published` parameter which allows the caller
+ * to know if a trace chunk equivalent to `chunk` was previously published.
+ * 
+ * The registry holds a reference to the published trace chunks it contains.
+ * Trace chunks automatically unpublish themselves from their registry on
+ * destruction.
+ *
+ * This information is necessary to drop the reference of newly published
+ * chunks when a user doesn't wish to explicitly maintain all references
+ * to a given trace chunk.
+ * 
+ * For instance, the relay daemon doesn't need the registry to hold a
+ * reference since it controls the lifetime of its trace chunks.
+ * Conversely, the consumer daemons rely on the session daemon to inform
+ * them of the end of life of a trace chunk and the trace chunks don't
+ * belong to a specific top-level object: they are always retrieved from
+ * the registry by `id`.
+ */
+struct lttng_trace_chunk *lttng_trace_chunk_registry_publish_chunk_published(
+               struct lttng_trace_chunk_registry *registry,
+               uint64_t session_id, struct lttng_trace_chunk *chunk,
+               bool *previously_published);
+
 /*
  * Look-up a trace chunk by session_id and chunk_id.
  * A reference is acquired on behalf of the caller.