tools: nfdc creates Face and KeyChain in main function

refs #3749

Change-Id: I169ad766634371b0192ebae640355298b78aaaa4
diff --git a/tools/nfdc/execute-command.hpp b/tools/nfdc/execute-command.hpp
new file mode 100644
index 0000000..31b2d52
--- /dev/null
+++ b/tools/nfdc/execute-command.hpp
@@ -0,0 +1,62 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (c) 2014-2016,  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_TOOLS_NFDC_EXECUTE_COMMAND_HPP
+#define NFD_TOOLS_NFDC_EXECUTE_COMMAND_HPP
+
+#include "command-arguments.hpp"
+#include <ndn-cxx/face.hpp>
+#include <ndn-cxx/security/key-chain.hpp>
+
+namespace nfd {
+namespace tools {
+namespace nfdc {
+
+using ndn::Face;
+using ndn::KeyChain;
+
+/** \brief context for command execution
+ */
+struct ExecuteContext
+{
+  const std::string& noun;
+  const std::string& verb;
+  const CommandArguments& args;
+
+  Face& face;
+  KeyChain& keyChain;
+  ///\todo validator
+};
+
+/** \brief a function to execute a command
+ *  \return exit code
+ */
+typedef std::function<int(ExecuteContext& ctx)> ExecuteCommand;
+
+} // namespace nfdc
+} // namespace tools
+} // namespace nfd
+
+#endif // NFD_TOOLS_NFDC_EXECUTE_COMMAND_HPP