From 90c366f369cec69468e5a05518f7e4b57ed56dc2 Mon Sep 17 00:00:00 2001
From: FengShun <fengshun95@gmail.com>
Date: Mon, 26 Oct 2020 17:29:00 +0800
Subject: [PATCH] uORB::Publication*: template parameter automatically obtains
 the queue size according to the type

---
 src/modules/uORB/Publication.hpp      | 20 +++++++++++++++++++-
 src/modules/uORB/PublicationMulti.hpp |  2 +-
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/src/modules/uORB/Publication.hpp b/src/modules/uORB/Publication.hpp
index 90f98603ba..0f2256af0a 100644
--- a/src/modules/uORB/Publication.hpp
+++ b/src/modules/uORB/Publication.hpp
@@ -48,6 +48,24 @@
 namespace uORB
 {
 
+template <typename U> class DefaultQueueSize
+{
+private:
+	template <typename T>
+	static constexpr uint8_t get_queue_size(decltype(T::ORB_QUEUE_LENGTH) *)
+	{
+		return T::ORB_QUEUE_LENGTH;
+	}
+
+	template <typename T> static constexpr uint8_t get_queue_size(...)
+	{
+		return 1;
+	}
+
+public:
+	static constexpr unsigned value = get_queue_size<U>(nullptr);
+};
+
 class PublicationBase
 {
 public:
@@ -79,7 +97,7 @@ protected:
 /**
  * uORB publication wrapper class
  */
-template<typename T, uint8_t ORB_QSIZE = 1>
+template<typename T, uint8_t ORB_QSIZE = DefaultQueueSize<T>::value>
 class Publication : public PublicationBase
 {
 public:
diff --git a/src/modules/uORB/PublicationMulti.hpp b/src/modules/uORB/PublicationMulti.hpp
index e54afd7365..b4aafe4e9a 100644
--- a/src/modules/uORB/PublicationMulti.hpp
+++ b/src/modules/uORB/PublicationMulti.hpp
@@ -50,7 +50,7 @@ namespace uORB
 /**
  * Base publication multi wrapper class
  */
-template<typename T, uint8_t QSIZE = 1>
+template<typename T, uint8_t QSIZE = DefaultQueueSize<T>::value>
 class PublicationMulti : public PublicationBase
 {
 public: