catchunks: add metadata-based version discovery

refs: #4556
Change-Id: I1100d1a4f14da8e66d190a7909185d67f7aa92a7
diff --git a/tools/chunks/catchunks/discover-version-realtime.cpp b/tools/chunks/catchunks/discover-version-realtime.cpp
new file mode 100644
index 0000000..7175211
--- /dev/null
+++ b/tools/chunks/catchunks/discover-version-realtime.cpp
@@ -0,0 +1,79 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/*
+ * Copyright (c) 2016-2019, Regents of the University of California,
+ *                          Colorado State University,
+ *                          University Pierre & Marie Curie, Sorbonne University.
+ *
+ * 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/>.
+ *
+ * See AUTHORS.md for complete list of ndn-cxx authors and contributors.
+ *
+ * @author Chavoosh Ghasemi <chghasemi@cs.arizona.edu>
+ */
+
+#include "discover-version-realtime.hpp"
+
+#include <ndn-cxx/metadata-object.hpp>
+
+namespace ndn {
+namespace chunks {
+
+DiscoverVersionRealtime::DiscoverVersionRealtime(const Name& prefix,
+                                                 Face& face,
+                                                 const Options& options)
+  : chunks::Options(options)
+  , DiscoverVersion(prefix, face)
+  , Options(options)
+{
+}
+
+void
+DiscoverVersionRealtime::run()
+{
+  expressInterest(MetadataObject::makeDiscoveryInterest(m_prefix)
+                  .setInterestLifetime(discoveryTimeout),
+                  maxRetriesOnTimeoutOrNack, maxRetriesOnTimeoutOrNack);
+}
+
+void
+DiscoverVersionRealtime::handleData(const Interest& interest, const Data& data)
+{
+  if (isVerbose)
+    std::cerr << "Data: " << data << std::endl;
+
+  // make a metadata object from received metadata packet
+  MetadataObject mobject;
+  try {
+    mobject = MetadataObject(data);
+  }
+  catch (const tlv::Error& e) {
+    this->emitSignal(onDiscoveryFailure, "Invalid metadata packet: "s + e.what());
+    return;
+  }
+
+  if (mobject.getVersionedName().empty() || !mobject.getVersionedName()[-1].isVersion()) {
+    this->emitSignal(onDiscoveryFailure, mobject.getVersionedName().toUri() +
+                                         " is not a valid versioned name");
+    return;
+  }
+
+  if (isVerbose) {
+    std::cerr << "Discovered Data version: " << mobject.getVersionedName()[-1].toVersion() << std::endl;
+  }
+  this->emitSignal(onDiscoverySuccess, mobject.getVersionedName());
+}
+
+} // namespace chunks
+} // namespace ndn