X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fbin%2Flttng-relayd%2Fviewer-session.hpp;fp=src%2Fbin%2Flttng-relayd%2Fviewer-session.hpp;h=65ad3e11a8165fe4fa3ec973f7bd42f49ff83e54;hp=0000000000000000000000000000000000000000;hb=c9e313bc594f40a86eed237dce222c0fc99c957f;hpb=4878de5c7deb512bbdac4fdfc498907efa06fb7c

diff --git a/src/bin/lttng-relayd/viewer-session.hpp b/src/bin/lttng-relayd/viewer-session.hpp
new file mode 100644
index 000000000..65ad3e11a
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+++ b/src/bin/lttng-relayd/viewer-session.hpp
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+#ifndef _VIEWER_SESSION_H
+#define _VIEWER_SESSION_H
+
+/*
+ * Copyright (C) 2013 Julien Desfossez <jdesfossez@efficios.com>
+ * Copyright (C) 2013 David Goulet <dgoulet@efficios.com>
+ * Copyright (C) 2015 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-only
+ *
+ */
+
+#include <limits.h>
+#include <inttypes.h>
+#include <pthread.h>
+#include <urcu/list.h>
+#include <urcu/ref.h>
+
+#include <common/hashtable/hashtable.hpp>
+#include <common/trace-chunk.hpp>
+
+#include "session.hpp"
+#include "lttng-viewer-abi.hpp"
+
+struct relay_viewer_session {
+	/*
+	 * Session list. Updates are protected by the session_list_lock.
+	 * Traversals are protected by RCU.
+	 * This list limits the design to having the sessions in at most
+	 * one viewer session.
+	 */
+	struct cds_list_head session_list;	/* RCU list. */
+	pthread_mutex_t session_list_lock;	/* Protects list updates. */
+	/*
+	 * The viewer session's current trace chunk is initially set, when
+	 * a viewer attaches to the viewer session, to a copy the corresponding
+	 * relay_session's current trace chunk.
+	 *
+	 * A live session always attempts to "catch-up" to the newest available
+	 * trace chunk. This means that when a viewer reaches the end of a
+	 * trace chunk, the viewer session may not transition to the "next" one:
+	 * it jumps to the most recent trace chunk available (the one being
+	 * produced by the relay_session). Hence, if the producer performs
+	 * multiple rotations before a viewer completes the consumption of a
+	 * trace chunk, it will skip over those "intermediary" trace chunks.
+	 *
+	 * A viewer session updates its current trace chunk when:
+	 *   1) new viewer streams are created,
+	 *   2) a new index is requested,
+	 *   3) metadata is requested.
+	 *
+	 * Hence, as a general principle, the viewer session will reference the
+	 * most recent trace chunk available _even if its streams do not point to
+	 * it_. It indicates which trace chunk viewer streams should transition
+	 * to when the end of their current trace chunk is reached.
+	 *
+	 * Note that a viewer session's trace chunk points to the session's
+	 * output directory. The sub-directories in which the various stream files
+	 * are created are considered as being a part of their name.
+	 */
+	struct lttng_trace_chunk *current_trace_chunk;
+};
+
+struct relay_viewer_session *viewer_session_create(void);
+void viewer_session_destroy(struct relay_viewer_session *vsession);
+void viewer_session_close(struct relay_viewer_session *vsession);
+
+enum lttng_viewer_attach_return_code viewer_session_attach(
+		struct relay_viewer_session *vsession,
+		struct relay_session *session);
+int viewer_session_is_attached(struct relay_viewer_session *vsession,
+		struct relay_session *session);
+void viewer_session_close_one_session(struct relay_viewer_session *vsession,
+		struct relay_session *session);
+int viewer_session_set_trace_chunk_copy(struct relay_viewer_session *vsession,
+		struct lttng_trace_chunk *relay_session_trace_chunk);
+
+#endif /* _VIEWER_SESSION_H */