add logger response

Change-Id: I2a2888eaf27671374ba8ed7f36ca2d1ffb736ea4
diff --git a/core/logger-response.hpp b/core/logger-response.hpp
new file mode 100644
index 0000000..8a393e4
--- /dev/null
+++ b/core/logger-response.hpp
@@ -0,0 +1,98 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (c) 2014,  Regents of the University of California
+ *
+ * This file is part of NSL (NDN Signature Logger).
+ * See AUTHORS.md for complete list of NSL authors and contributors.
+ *
+ * NSL 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.
+ *
+ * NSL 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
+ * NSL, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * See AUTHORS.md for complete list of nsl authors and contributors.
+ */
+
+#ifndef NSL_CORE_LOGGER_RESPONSE_HPP
+#define NSL_CORE_LOGGER_RESPONSE_HPP
+
+#include "common.hpp"
+#include "util/non-negative-integer.hpp"
+#include <ndn-cxx/encoding/buffer.hpp>
+
+namespace nsl {
+
+class LoggerResponse
+{
+public:
+  class Error : public std::runtime_error
+  {
+  public:
+    explicit
+    Error(const std::string& what)
+      : std::runtime_error(what)
+    {
+    }
+  };
+
+public:
+  LoggerResponse();
+
+  LoggerResponse(int32_t resultCode, const std::string& resultMsg);
+
+  LoggerResponse(const NonNegativeInteger& seqNo);
+
+  int32_t
+  getCode() const
+  {
+    return m_code;
+  }
+
+  const std::string&
+  getMsg() const
+  {
+    if (m_code == 0)
+      throw Error("Error msg is not available");
+
+    return m_msg;
+  }
+
+  const NonNegativeInteger&
+  getDataSeqNo() const
+  {
+    if (m_code != 0)
+      throw Error("Data seqNo is not available");
+
+    return m_dataSeqNo;
+  }
+
+  /// @brief Encode to a wire format or estimate wire format
+  template<ndn::encoding::Tag TAG>
+  size_t
+  wireEncode(ndn::EncodingImpl<TAG>& block) const;
+
+  /// @brief Encode to a wire format
+  const Block&
+  wireEncode() const;
+
+  /// @brief Decode from a wire format
+  void
+  wireDecode(const Block& wire);
+
+private:
+  int32_t m_code;
+  std::string m_msg; // optional
+  NonNegativeInteger m_dataSeqNo; // optional
+
+  mutable Block m_wire;
+};
+
+} // namespace nsl
+
+#endif // NSL_CORE_LOGGER_RESPONSE_HPP