rib: Use only a forward declaration of RibManager in the header of Nrd class

Change-Id: I8a681dc9a75ac8cdabc289e685ec6a505cfb5aac

rib/nrd.cpp

@@ -52,6 +52,13 @@ Nrd::Nrd(const ConfigSection& config, ndn::KeyChain& keyChain)
 {
 }
 
+Nrd::~Nrd()
+{
+  // It is necessary to explicitly define the destructor, because some member variables
+  // (e.g., unique_ptr<RibManager>) are forward-declared, but implicitly declared destructor
+  // requires complete types for all members when instantiated.
+}
+
 void
 Nrd::initialize()
 {

rib/nrd.hpp

@@ -28,7 +28,6 @@
 
 #include "common.hpp"
 #include "core/config-file.hpp"
-#include "rib-manager.hpp"
 
 #include <ndn-cxx/face.hpp>
 #include <ndn-cxx/security/key-chain.hpp>
@@ -37,6 +36,8 @@
 namespace nfd {
 namespace rib {
 
+class RibManager;
+
 /**
  * \brief Class representing NRD (NFD RIB Manager) instance
  * This class can be used to initialize all components of NRD
@@ -68,6 +69,11 @@ public:
    */
   Nrd(const ConfigSection& config, ndn::KeyChain& keyChain);
 
+  /**
+   * \brief Destructor
+   */
+  ~Nrd();
+
   /**
    * \brief Perform initialization of NFD instance
    * After initialization, NFD instance can be started by invoking run on globalIoService