Rename C++ header files to .hpp

[lttng-tools.git] / src / bin / lttng-relayd / viewer-session.hpp

diff --git a/src/bin/lttng-relayd/viewer-session.hpp b/src/bin/lttng-relayd/viewer-session.hpp
new file mode 100644 (file)
index 0000000..65ad3e1
--- /dev/null
+++ b/src/bin/lttng-relayd/viewer-session.hpp
@@ -0,0 +1,78 @@
+#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 */