sessiond: add smart pointer utils for ltt_session

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

diff --git a/src/bin/lttng-sessiond/session.hpp b/src/bin/lttng-sessiond/session.hpp
index ad451336a5b5b430ad49a9d8e99c3bdb26a07429..17f3ca13970ae53f0e84001f7565fc92df8cbc89 100644 (file)
--- a/src/bin/lttng-sessiond/session.hpp
+++ b/src/bin/lttng-sessiond/session.hpp
@@ -14,6 +14,7 @@
 
 #include <common/hashtable/hashtable.hpp>
 #include <common/dynamic-array.hpp>
+#include <common/make-unique-wrapper.hpp>
 #include <lttng/rotation.h>
 #include <lttng/location.h>
 #include <lttng/lttng-error.h>
@@ -31,6 +32,14 @@ typedef void (*ltt_session_destroy_notifier)(const struct ltt_session *session,
 typedef void (*ltt_session_clear_notifier)(const struct ltt_session *session,
                void *user_data);
 
+namespace lttng {
+namespace sessiond {
+namespace details {
+void locked_session_release(ltt_session *session);
+} /* namespace details */
+} /* namespace sessiond */
+} /* namespace lttng */
+
 /*
  * Tracing session list
  *
@@ -67,6 +76,12 @@ struct ltt_session_list {
  * session for both LTTng and UST.
  */
 struct ltt_session {
+       using id_t = uint64_t;
+       using locked_ptr = std::unique_ptr<ltt_session,
+                       lttng::details::create_unique_class<ltt_session,
+                                       lttng::sessiond::details::locked_session_release>::deleter>;
+       using sptr = std::shared_ptr<ltt_session>;
+
        char name[NAME_MAX];
        bool has_auto_generated_name;
        bool name_contains_creation_time;
@@ -84,7 +99,8 @@ struct ltt_session {
         */
        pthread_mutex_t lock;
        struct cds_list_head list;
-       uint64_t id;            /* session unique identifier */
+       /* session unique identifier */
+       id_t id;
        /* Indicates if the session has been added to the session list and ht.*/
        bool published;
        /* Indicates if a destroy command has been applied to this session. */
@@ -240,7 +256,7 @@ struct lttng_trace_archive_location *session_get_trace_archive_location(
                const struct ltt_session *session);
 
 struct ltt_session *session_find_by_name(const char *name);
-struct ltt_session *session_find_by_id(uint64_t id);
+struct ltt_session *session_find_by_id(ltt_session::id_t id);
 
 struct ltt_session_list *session_get_list(void);
 void session_list_wait_empty(void);
@@ -294,4 +310,26 @@ bool session_output_supports_trace_chunks(const struct ltt_session *session);
  */
 bool sample_session_id_by_name(const char *name, uint64_t *id);
 
+namespace lttng {
+namespace sessiond {
+
+/*
+ * Session list lock must be acquired by the caller.
+ * The caller must not keep the ownership of the returned locked session
+ * for longer than strictly necessary. If your intention is to acquire
+ * a reference to an ltt_session, see `find_session_by_id()`.
+ */
+ltt_session::locked_ptr find_locked_session_by_id(ltt_session::id_t id);
+
+/*
+ * Session list lock must be acquired by the caller.
+ * The caller must not keep the ownership of the returned locked session
+ * for longer than strictly necessary. If your intention is to acquire
+ * a reference to an ltt_session, see `find_session_by_id()`.
+ */
+ltt_session::sptr find_session_by_id(ltt_session::id_t id);
+
+} /* namespace sessiond */
+} /* namespace lttng */
+
 #endif /* _LTT_SESSION_H */