Move immediate connection notification logic into Dispatcher.

This prevents a race condition that could result in out of order
notifications.

src/main/native/cpp/ConnectionNotifier.h

@@ -57,9 +57,9 @@ class ConnectionNotifier
 
   void Start();
 
-  unsigned int Add(
-      std::function<void(const ConnectionNotification& event)> callback);
-  unsigned int AddPolled(unsigned int poller_uid);
+  unsigned int Add(std::function<void(const ConnectionNotification& event)>
+                       callback) override;
+  unsigned int AddPolled(unsigned int poller_uid) override;
 
   void NotifyConnection(bool connected, const ConnectionInfo& conn_info,
                         unsigned int only_listener = UINT_MAX) override;

src/main/native/cpp/Dispatcher.cpp

@@ -239,6 +239,35 @@ bool DispatcherBase::IsConnected() const {
   return false;
 }
 
+unsigned int DispatcherBase::AddListener(
+    std::function<void(const ConnectionNotification& event)> callback,
+    bool immediate_notify) const {
+  std::lock_guard<std::mutex> lock(m_user_mutex);
+  unsigned int uid = m_notifier.Add(callback);
+  // perform immediate notifications
+  if (immediate_notify) {
+    for (auto& conn : m_connections) {
+      if (conn->state() != NetworkConnection::kActive) continue;
+      m_notifier.NotifyConnection(true, conn->info(), uid);
+    }
+  }
+  return uid;
+}
+
+unsigned int DispatcherBase::AddPolledListener(unsigned int poller_uid,
+                                               bool immediate_notify) const {
+  std::lock_guard<std::mutex> lock(m_user_mutex);
+  unsigned int uid = m_notifier.AddPolled(poller_uid);
+  // perform immediate notifications
+  if (immediate_notify) {
+    for (auto& conn : m_connections) {
+      if (conn->state() != NetworkConnection::kActive) continue;
+      m_notifier.NotifyConnection(true, conn->info(), uid);
+    }
+  }
+  return uid;
+}
+
 void DispatcherBase::SetConnector(Connector connector) {
   std::lock_guard<std::mutex> lock(m_user_mutex);
   m_client_connector = std::move(connector);

src/main/native/cpp/Dispatcher.h

@@ -56,6 +56,12 @@ class DispatcherBase : public IDispatcher {
   std::vector<ConnectionInfo> GetConnections() const;
   bool IsConnected() const;
 
+  unsigned int AddListener(
+      std::function<void(const ConnectionNotification& event)> callback,
+      bool immediate_notify) const;
+  unsigned int AddPolledListener(unsigned int poller_uid,
+                                 bool immediate_notify) const;
+
   void SetConnector(Connector connector);
   void SetConnectorOverride(Connector connector);
   void ClearConnectorOverride();

src/main/native/cpp/IConnectionNotifier.h

@@ -20,6 +20,9 @@ class IConnectionNotifier {
   IConnectionNotifier(const IConnectionNotifier&) = delete;
   IConnectionNotifier& operator=(const IConnectionNotifier&) = delete;
   virtual ~IConnectionNotifier() = default;
+  virtual unsigned int Add(
+      std::function<void(const ConnectionNotification& event)> callback) = 0;
+  virtual unsigned int AddPolled(unsigned int poller_uid) = 0;
   virtual void NotifyConnection(bool connected, const ConnectionInfo& conn_info,
                                 unsigned int only_listener = UINT_MAX) = 0;
 };

src/main/native/cpp/ntcore_cpp.cpp

@@ -388,11 +388,7 @@ NT_ConnectionListener AddConnectionListener(
   auto ii = InstanceImpl::Get(i);
   if (!ii) return 0;
 
-  unsigned int uid = ii->connection_notifier.Add(callback);
-  if (immediate_notify) {
-    for (auto& conn : ii->dispatcher.GetConnections())
-      ii->connection_notifier.NotifyConnection(true, conn, uid);
-  }
+  unsigned int uid = ii->dispatcher.AddListener(callback, immediate_notify);
   return Handle(i, uid, Handle::kConnectionListener);
 }
 
@@ -422,12 +418,7 @@ NT_ConnectionListener AddPolledConnectionListener(
   auto ii = InstanceImpl::Get(i);
   if (id < 0 || !ii) return 0;
 
-  unsigned int uid = ii->connection_notifier.AddPolled(id);
-  // perform immediate notifications
-  if (immediate_notify) {
-    for (auto& conn : ii->dispatcher.GetConnections())
-      ii->connection_notifier.NotifyConnection(true, conn, uid);
-  }
+  unsigned int uid = ii->dispatcher.AddPolledListener(id, immediate_notify);
   return Handle(i, uid, Handle::kConnectionListener);
 }
 

src/test/native/cpp/MockConnectionNotifier.h

@@ -16,6 +16,11 @@ namespace nt {
 
 class MockConnectionNotifier : public IConnectionNotifier {
  public:
+  MOCK_METHOD1(
+      Add,
+      unsigned int(
+          std::function<void(const ConnectionNotification& event)> callback));
+  MOCK_METHOD1(AddPolled, unsigned int(unsigned int poller_uid));
   MOCK_METHOD3(NotifyConnection,
                void(bool connected, const ConnectionInfo& conn_info,
                     unsigned int only_listener));