peek: Refactor ndnpeek and add unit tests

Change-Id: Ib34c4431bdc268c5a7ef2fccf0946b0d19d69ab6
Refs: #3558
diff --git a/tools/peek/ndnpeek/ndnpeek.hpp b/tools/peek/ndnpeek/ndnpeek.hpp
new file mode 100644
index 0000000..2b0a85e
--- /dev/null
+++ b/tools/peek/ndnpeek/ndnpeek.hpp
@@ -0,0 +1,112 @@
+/* -*- 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 ndn-tools (Named Data Networking Essential Tools).
+ * See AUTHORS.md for complete list of ndn-tools authors and contributors.
+ *
+ * ndn-tools 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.
+ *
+ * ndn-tools 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
+ * ndn-tools, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * @author Jerald Paul Abraham <jeraldabraham@email.arizona.edu>
+ * @author Zhuo Li <zhuoli@email.arizona.edu>
+ */
+
+#ifndef NDN_TOOLS_NDNPEEK_NDNPEEK_HPP
+#define NDN_TOOLS_NDNPEEK_NDNPEEK_HPP
+
+#include "core/common.hpp"
+
+namespace ndn {
+namespace peek {
+
+/**
+ * @brief options for NdnPeek
+ */
+struct PeekOptions
+{
+  std::string prefix;
+  int minSuffixComponents;
+  int maxSuffixComponents;
+  time::milliseconds interestLifetime;
+  time::milliseconds timeout;
+  shared_ptr<Link> link;
+  bool isVerbose;
+  bool mustBeFresh;
+  bool wantRightmostChild;
+  bool wantPayloadOnly;
+};
+
+enum class ResultCode {
+  NONE = -1,
+  DATA = 0,
+  NACK = 4,
+  TIMEOUT = 3
+};
+
+class NdnPeek : boost::noncopyable
+{
+public:
+  NdnPeek(Face& face, const PeekOptions& options);
+
+  /**
+   * @return the timeout
+   */
+  time::milliseconds
+  getTimeout() const;
+
+  /**
+   * @return the result of Peek execution
+   */
+  ResultCode
+  getResultCode() const;
+
+  /**
+   * @brief express the Interest
+   * @note The caller must invoke face.processEvents() afterwards
+   */
+  void
+  start();
+
+private:
+  Interest
+  createInterest() const;
+
+  /**
+   * @brief called when a Data packet is received
+   */
+  void
+  onData(const Data& data);
+
+  /**
+   * @brief called when a Nack packet is received
+   */
+  void
+  onNack(const lp::Nack& nack);
+
+private:
+  Face& m_face;
+  const PeekOptions& m_options;
+  time::steady_clock::TimePoint m_expressInterestTime;
+  time::milliseconds m_timeout;
+  ResultCode m_resultCode;
+};
+
+} // namespace peek
+} // namespace ndn
+
+#endif // NDN_TOOLS_NDNPEEK_NDNPEEK_HPP