From 342e08977ae5bf49c5ba941866e44fddefca4cda Mon Sep 17 00:00:00 2001
From: Anton Babushkin <anton.babushkin@me.com>
Date: Wed, 11 Jun 2014 14:00:44 +0200
Subject: MavlinkOrbSubscription API reworked

---
 src/modules/mavlink/mavlink_orb_subscription.cpp | 38 ++++++++++++++++--------
 1 file changed, 26 insertions(+), 12 deletions(-)

(limited to 'src/modules/mavlink/mavlink_orb_subscription.cpp')

diff --git a/src/modules/mavlink/mavlink_orb_subscription.cpp b/src/modules/mavlink/mavlink_orb_subscription.cpp
index 0a23fb01e..901fa8f05 100644
--- a/src/modules/mavlink/mavlink_orb_subscription.cpp
+++ b/src/modules/mavlink/mavlink_orb_subscription.cpp
@@ -50,7 +50,6 @@ MavlinkOrbSubscription::MavlinkOrbSubscription(const orb_id_t topic) :
 	_fd(orb_subscribe(_topic)),
 	_published(false),
 	_topic(topic),
-	_last_check(0),
 	next(nullptr)
 {
 }
@@ -67,24 +66,39 @@ MavlinkOrbSubscription::get_topic() const
 }
 
 bool
-MavlinkOrbSubscription::update(const hrt_abstime t, void* data)
+MavlinkOrbSubscription::update(uint64_t *time, void* data)
 {
-	if (_last_check == t) {
-		/* already checked right now, return result of the check */
-		return _updated;
+	// TODO this is NOT atomic operation, we can get data newer than time
+	// if topic was published between orb_stat and orb_copy calls.
 
-	} else {
-		_last_check = t;
-		orb_check(_fd, &_updated);
+	uint64_t time_topic;
+	if (orb_stat(_fd, &time_topic)) {
+		/* error getting last topic publication time */
+		time_topic = 0;
+	}
+
+	if (orb_copy(_topic, _fd, data)) {
+		/* error copying topic data */
+		memset(data, 0, _topic->o_size);
+		return false;
 
-		if (_updated && data) {
-			orb_copy(_topic, _fd, data);
-			_published = true;
+	} else {
+		/* data copied successfully */
+		_published = true;
+		if (time_topic != *time) {
+			*time = time_topic;
 			return true;
+
+		} else {
+			return false;
 		}
 	}
+}
 
-	return false;
+bool
+MavlinkOrbSubscription::update(void* data)
+{
+	return !orb_copy(_topic, _fd, data);
 }
 
 bool
-- 
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