From f01d28b41fb941aee87aaf70ed42a5928c784ba6 Mon Sep 17 00:00:00 2001
From: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>
Date: Fri, 7 Feb 2020 17:40:46 -0500
Subject: [PATCH 1/1] trigger: introduce refcounting
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Will be used for listing and much more use.

Signed-off-by: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Change-Id: Ic9ee8753257fcbe15fc1321b18582628328c0154
---
 include/lttng/trigger/trigger-internal.h | 10 ++++++++
 src/common/trigger.c                     | 31 ++++++++++++++++++++----
 2 files changed, 36 insertions(+), 5 deletions(-)

diff --git a/include/lttng/trigger/trigger-internal.h b/include/lttng/trigger/trigger-internal.h
index d857ff78e..4b031137c 100644
--- a/include/lttng/trigger/trigger-internal.h
+++ b/include/lttng/trigger/trigger-internal.h
@@ -15,11 +15,15 @@
 #include <stdint.h>
 #include <stdbool.h>
 #include <sys/types.h>
+#include <urcu/ref.h>
 
 struct lttng_payload;
 struct lttng_payload_view;
 
 struct lttng_trigger {
+	/* Reference counting is only exposed to internal users. */
+	struct urcu_ref ref;
+
 	struct lttng_condition *condition;
 	struct lttng_action *action;
 	LTTNG_OPTIONAL(struct lttng_credentials) creds;
@@ -51,6 +55,12 @@ const struct lttng_action *lttng_trigger_get_const_action(
 LTTNG_HIDDEN
 bool lttng_trigger_validate(struct lttng_trigger *trigger);
 
+LTTNG_HIDDEN
+void lttng_trigger_get(struct lttng_trigger *trigger);
+
+LTTNG_HIDDEN
+void lttng_trigger_put(struct lttng_trigger *trigger);
+
 LTTNG_HIDDEN
 const struct lttng_credentials *lttng_trigger_get_credentials(
 		const struct lttng_trigger *trigger);
diff --git a/src/common/trigger.c b/src/common/trigger.c
index 2ccf00735..2ef77b236 100644
--- a/src/common/trigger.c
+++ b/src/common/trigger.c
@@ -46,6 +46,8 @@ struct lttng_trigger *lttng_trigger_create(
 		goto end;
 	}
 
+	urcu_ref_init(&trigger->ref);
+
 	lttng_condition_get(condition);
 	trigger->condition = condition;
 
@@ -93,16 +95,14 @@ const struct lttng_action *lttng_trigger_get_const_action(
 	return trigger->action;
 }
 
-void lttng_trigger_destroy(struct lttng_trigger *trigger)
+static void trigger_destroy_ref(struct urcu_ref *ref)
 {
+	struct lttng_trigger *trigger =
+			container_of(ref, struct lttng_trigger, ref);
 	struct lttng_action *action = lttng_trigger_get_action(trigger);
 	struct lttng_condition *condition =
 			lttng_trigger_get_condition(trigger);
 
-	if (!trigger) {
-		return;
-	}
-
 	assert(action);
 	assert(condition);
 
@@ -113,6 +113,11 @@ void lttng_trigger_destroy(struct lttng_trigger *trigger)
 	free(trigger);
 }
 
+void lttng_trigger_destroy(struct lttng_trigger *trigger)
+{
+	lttng_trigger_put(trigger);
+}
+
 LTTNG_HIDDEN
 ssize_t lttng_trigger_create_from_payload(
 		struct lttng_payload_view *src_view,
@@ -231,6 +236,22 @@ end:
 	return ret;
 }
 
+LTTNG_HIDDEN
+void lttng_trigger_get(struct lttng_trigger *trigger)
+{
+	urcu_ref_get(&trigger->ref);
+}
+
+LTTNG_HIDDEN
+void lttng_trigger_put(struct lttng_trigger *trigger)
+{
+	if (!trigger) {
+		return;
+	}
+
+	urcu_ref_put(&trigger->ref , trigger_destroy_ref);
+}
+
 LTTNG_HIDDEN
 const struct lttng_credentials *lttng_trigger_get_credentials(
 		const struct lttng_trigger *trigger)
-- 
2.34.1