fw: add FaceEndpoint parameter in Forwarding and Strategy API

refs: #4849

Change-Id: Ibe22557488fa83a555fd13d6eb8e03f8d81d0b2b
diff --git a/daemon/fw/face-endpoint.hpp b/daemon/fw/face-endpoint.hpp
new file mode 100644
index 0000000..acfbc2e
--- /dev/null
+++ b/daemon/fw/face-endpoint.hpp
@@ -0,0 +1,57 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/*
+ * Copyright (c) 2014-2019,  Regents of the University of California,
+ *                           Arizona Board of Regents,
+ *                           Colorado State University,
+ *                           University Pierre & Marie Curie, Sorbonne University,
+ *                           Washington University in St. Louis,
+ *                           Beijing Institute of Technology,
+ *                           The University of Memphis.
+ *
+ * This file is part of NFD (Named Data Networking Forwarding Daemon).
+ * See AUTHORS.md for complete list of NFD authors and contributors.
+ *
+ * NFD is free software: you can redistribute it and/or modify it under the terms
+ * of the GNU General Public License as published by the Free Software Foundation,
+ * either version 3 of the License, or (at your option) any later version.
+ *
+ * NFD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
+ * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+ * PURPOSE.  See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * NFD, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef NFD_DAEMON_FW_FACE_ENDPOINT_HPP
+#define NFD_DAEMON_FW_FACE_ENDPOINT_HPP
+
+#include "face/face.hpp"
+
+namespace nfd {
+
+/** \brief Represents a face-endpoint pair in the forwarder
+ */
+class FaceEndpoint
+{
+public:
+  FaceEndpoint(const Face& face, EndpointId endpoint)
+    : face(const_cast<Face&>(face))
+    , endpoint(endpoint)
+  {
+  }
+
+public:
+  Face& face;
+  const EndpointId endpoint;
+};
+
+inline std::ostream&
+operator<<(std::ostream& os, const FaceEndpoint& fe)
+{
+  return os << "(" << fe.face.getId() << "," << fe.endpoint << ")";
+}
+
+} // namespace nfd
+
+#endif // NFD_DAEMON_FW_FACE_ENDPOINT_HPP
\ No newline at end of file