Add the trace chunk and trace chunk registry interfaces

[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
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+++ b/src/common/trace-chunk-registry.h
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+/*
+ * 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.
+ *
+ * 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
+#define LTTNG_TRACE_CHUNK_REGISTRY_H
+
+#include <stddef.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <common/macros.h>
+#include <common/trace-chunk.h>
+
+struct lttng_trace_chunk_registry;
+
+/*
+ * Create an lttng_trace_chunk registry.
+ *
+ * A trace chunk registry maintains an association between a
+ * (session_id, chunk_id) tuple and a trace chunk object. The chunk_id can
+ * be "unset" in the case of an anonymous trace chunk.
+ *
+ * Note that a trace chunk registry holds no ownership of its trace
+ * chunks. Trace chunks are unpublished when their last reference is released.
+ * See the documentation of lttng_trace_chunk.
+ *
+ * Returns a trace chunk registry on success, NULL on error.
+ *
+ * Note that a trace chunk registry may only be accessed by an RCU thread.
+ */
+LTTNG_HIDDEN
+struct lttng_trace_chunk_registry *lttng_trace_chunk_registry_create(void);
+
+/*
+ * Destroy an lttng trace chunk registry. The registry must be emptied
+ * (i.e. all references to the trace chunks it contains must be released) before
+ * it is destroyed.
+ */
+LTTNG_HIDDEN
+void lttng_trace_chunk_registry_destroy(
+               struct lttng_trace_chunk_registry *registry);
+
+/*
+ * Publish a trace chunk for a given session id.
+ * A reference is acquired on behalf of the caller.
+ *
+ * The trace chunk that is returned is the published version of the trace
+ * chunk. The chunk provided should be discarded on success and it's
+ * published version used in its place.
+ *
+ * See the documentation of lttng_trace_chunk for more information on
+ * the usage of the various parameters.
+ *
+ * Returns an lttng_trace_chunk on success, NULL on error.
+ */
+LTTNG_HIDDEN
+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);
+
+/*
+ * Look-up a trace chunk by session_id and chunk_id.
+ * A reference is acquired on behalf of the caller.
+ *
+ * Returns an lttng_trace_chunk on success, NULL if the chunk does not exist.
+ */
+LTTNG_HIDDEN
+struct lttng_trace_chunk *
+lttng_trace_chunk_registry_find_chunk(
+               const struct lttng_trace_chunk_registry *registry,
+               uint64_t session_id, uint64_t chunk_id);
+
+/*
+ * Look-up an anonymous trace chunk by session_id.
+ * A reference is acquired on behalf of the caller.
+ *
+ * Returns an lttng_trace_chunk on success, NULL if the chunk does not exist.
+ */
+LTTNG_HIDDEN
+struct lttng_trace_chunk *
+lttng_trace_chunk_registry_find_anonymous_chunk(
+               const struct lttng_trace_chunk_registry *registry,
+               uint64_t session_id);
+
+#endif /* LTTNG_TRACE_CHUNK_REGISTRY_H */