From fe650ea463f79d205d446a6f62b2e0016dbdf52e Mon Sep 17 00:00:00 2001
From: Philippe Proulx <eeppeliteloop@gmail.com>
Date: Tue, 25 Apr 2017 20:40:59 -0400
Subject: [PATCH] Freeze bt_clock_class_priority_map in related notifications
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We don't want the relative priorities of a notification's clock classes
(event, inactivity) to change once it's emitted.

Should a new clock class be needed (with its own priority), you should
create a new clock class priority map.

Signed-off-by: Philippe Proulx <eeppeliteloop@gmail.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
---
 .../graph/clock-class-priority-map-internal.h        | 12 ++++++++++++
 include/babeltrace/graph/clock-class-priority-map.h  | 11 +++++++++++
 lib/graph/clock-class-priority-map.c                 |  2 +-
 lib/graph/notification/event.c                       |  2 ++
 lib/graph/notification/inactivity.c                  |  2 ++
 5 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/include/babeltrace/graph/clock-class-priority-map-internal.h b/include/babeltrace/graph/clock-class-priority-map-internal.h
index 57c6c86a..3cba2bb9 100644
--- a/include/babeltrace/graph/clock-class-priority-map-internal.h
+++ b/include/babeltrace/graph/clock-class-priority-map-internal.h
@@ -28,6 +28,8 @@
 
 #include <stdint.h>
 #include <stddef.h>
+#include <stdbool.h>
+#include <assert.h>
 #include <babeltrace/ctf-ir/clock-class.h>
 #include <babeltrace/object-internal.h>
 #include <glib.h>
@@ -43,6 +45,16 @@ struct bt_clock_class_priority_map {
 
 	/* Clock class (weak) with the currently highest priority */
 	struct bt_ctf_clock_class *highest_prio_cc;
+
+	bool frozen;
 };
 
+static inline
+void bt_clock_class_priority_map_freeze(
+		struct bt_clock_class_priority_map *cc_prio_map)
+{
+	assert(cc_prio_map);
+	cc_prio_map->frozen = true;
+}
+
 #endif /* BABELTRACE_GRAPH_CLOCK_CLASS_PRIORITY_MAP_INTERNAL_H */
diff --git a/include/babeltrace/graph/clock-class-priority-map.h b/include/babeltrace/graph/clock-class-priority-map.h
index 18c27308..575e31c1 100644
--- a/include/babeltrace/graph/clock-class-priority-map.h
+++ b/include/babeltrace/graph/clock-class-priority-map.h
@@ -56,6 +56,16 @@ A priority is a 64-bit unsigned integer. A lower value has a
 \em higher priority. Multiple clock classes can have the same priority
 within a given clock class priority map.
 
+The following functions can \em freeze clock class priority map objects:
+
+- bt_notification_event_create() freezes its clock class priority
+  map parameter.
+- bt_notification_inactivity_create() freezes its clock class priority
+  map parameter.
+
+You cannot modify a frozen clock class priority map object: it is
+considered immutable, except for \link refs reference counting\endlink.
+
 As with any Babeltrace object, clock class priority map objects have
 <a href="https://en.wikipedia.org/wiki/Reference_counting">reference
 counts</a>. See \ref refs to learn more about the reference counting
@@ -256,6 +266,7 @@ map.
 
 @prenotnull{clock_class_priority_map}
 @prenotnull{clock_class}
+@prehot{clock_class_priority_map}
 @postrefcountsame{clock_class_priority_map}
 @postsuccessrefcountinc{clock_class}
 
diff --git a/lib/graph/clock-class-priority-map.c b/lib/graph/clock-class-priority-map.c
index f9055198..136ed276 100644
--- a/lib/graph/clock-class-priority-map.c
+++ b/lib/graph/clock-class-priority-map.c
@@ -229,7 +229,7 @@ int bt_clock_class_priority_map_add_clock_class(
 
 	// FIXME when available: check
 	// bt_ctf_clock_class_is_valid(clock_class)
-	if (!cc_prio_map) {
+	if (!cc_prio_map || !clock_class || cc_prio_map->frozen) {
 		ret = -1;
 		goto end;
 	}
diff --git a/lib/graph/notification/event.c b/lib/graph/notification/event.c
index 6a1903dc..44bb6f23 100644
--- a/lib/graph/notification/event.c
+++ b/lib/graph/notification/event.c
@@ -31,6 +31,7 @@
 #include <babeltrace/ctf-ir/stream-class-internal.h>
 #include <babeltrace/ctf-ir/trace.h>
 #include <babeltrace/graph/clock-class-priority-map.h>
+#include <babeltrace/graph/clock-class-priority-map-internal.h>
 #include <babeltrace/graph/notification-event-internal.h>
 
 static
@@ -144,6 +145,7 @@ struct bt_notification *bt_notification_event_create(struct bt_ctf_event *event,
 	}
 
 	bt_ctf_event_freeze(notification->event);
+	bt_clock_class_priority_map_freeze(notification->cc_prio_map);
 	return &notification->parent;
 error:
 	bt_put(notification);
diff --git a/lib/graph/notification/inactivity.c b/lib/graph/notification/inactivity.c
index 48073955..27b6916f 100644
--- a/lib/graph/notification/inactivity.c
+++ b/lib/graph/notification/inactivity.c
@@ -24,6 +24,7 @@
 #include <babeltrace/compiler-internal.h>
 #include <babeltrace/ctf-ir/clock-class.h>
 #include <babeltrace/graph/clock-class-priority-map.h>
+#include <babeltrace/graph/clock-class-priority-map-internal.h>
 #include <babeltrace/graph/notification-internal.h>
 #include <babeltrace/graph/notification-inactivity-internal.h>
 
@@ -67,6 +68,7 @@ struct bt_notification *bt_notification_inactivity_create(
 	}
 
 	notification->cc_prio_map = bt_get(cc_prio_map);
+	bt_clock_class_priority_map_freeze(cc_prio_map);
 	goto end;
 
 error:
-- 
2.34.1