From dbb8b67ad80b73a1154840f7d56434448bdfa8a3 Mon Sep 17 00:00:00 2001
From: Tommaso Pecorella <tommaso.pecorella@unifi.it>
Date: Wed, 1 Sep 2021 04:13:57 +0200
Subject: [PATCH] core (fixes #452) Add TracedCallback::IsEmpty

---
 CHANGES.html                     |  1 +
 RELEASE_NOTES                    |  1 +
 src/core/model/traced-callback.h | 12 ++++++++++++
 3 files changed, 14 insertions(+)

diff --git a/CHANGES.html b/CHANGES.html
index 2a3c8b49e..7420262f4 100644
--- a/CHANGES.html
+++ b/CHANGES.html
@@ -59,6 +59,7 @@ us a note on ns-developers mailing list.</p>
 <li>With the new support for IPv6 Nix-Vector routing, we have all the new APIs corresponding to IPv4 Nix-Vector routing. Specific to the user, there is an Ipv6NixVectorHelper class which can be set in the InternetStackHelper, and works similar to Ipv4NixVectorHelper.</li>
 <li>In class <b>Ipv4InterfaceAddress</b>, a new function IsInSameSubnet () is added to check if both the IPv4 addresses are in the same subnet. Also, it is consistent with <b>Ipv6InterfaceAddress::IsInSameSubnet ()</b>.</li>
 <li>In class <b>ConfigStore</b>, a new Attribue <b>SaveDeprecated</b> allows to not save DEPRECATED Attributes. The default value is <b>false</b> (save DEPRECATED Attributes).</li>
+<li>In class <b>TracedCallback</b>, a new function <b>IsEmpty</b> allows to know if the TracedCallback will call any callback.</li>
 </ul>
 <h2>Changes to existing API:</h2>
 <ul>
diff --git a/RELEASE_NOTES b/RELEASE_NOTES
index 8dd510880..b24fd480f 100644
--- a/RELEASE_NOTES
+++ b/RELEASE_NOTES
@@ -35,6 +35,7 @@ New user-visible features
 - (nix-vector-routing) Nix-Vector routing supports topologies with multiple WiFi networks using the same WiFi channel object.
 - (config-store) OBSOLETE Attributes are not anymore saved.
 - (config-store) New ConfigStore::SaveDeprecated Attribute (default false) to avoid to save DEPRECATED attributes.
+- (core) Add TracedCallback::IsEmpty to know if a TracedCallback has any callback associated.
 
 Bugs fixed
 ----------
diff --git a/src/core/model/traced-callback.h b/src/core/model/traced-callback.h
index b264953cc..83dc75852 100644
--- a/src/core/model/traced-callback.h
+++ b/src/core/model/traced-callback.h
@@ -89,6 +89,11 @@ public:
    * \param [in] args The arguments to the functor
    */
   void operator() (Ts... args) const;
+  /**
+   * \brief Checks if the Callbacks list is empty.
+   * \return true if the Callbacks list is empty.
+   */
+  bool IsEmpty () const;
 
   /**
    *  TracedCallback signature for POD.
@@ -188,6 +193,13 @@ TracedCallback<Ts...>::operator() (Ts... args) const
     }
 }
 
+template <typename... Ts>
+bool
+TracedCallback<Ts...>::IsEmpty () const
+{
+  return m_callbackList.empty ();
+}
+
 } // namespace ns3
 
 #endif /* TRACED_CALLBACK_H */