mgmt: encode and decode prefix announcement object

refs #4650

Change-Id: Ie8de492aac1ea9fd51ddc6b50f239913989abe72
diff --git a/src/prefix-announcement.cpp b/src/prefix-announcement.cpp
new file mode 100644
index 0000000..6149526
--- /dev/null
+++ b/src/prefix-announcement.cpp
@@ -0,0 +1,119 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/*
+ * Copyright (c) 2013-2018 Regents of the University of California.
+ *
+ * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
+ *
+ * ndn-cxx library is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU Lesser General Public License as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option) any later version.
+ *
+ * ndn-cxx library 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 Lesser General Public License for more details.
+ *
+ * You should have received copies of the GNU General Public License and GNU Lesser
+ * General Public License along with ndn-cxx, 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.
+ */
+
+#include "prefix-announcement.hpp"
+#include "encoding/tlv-nfd.hpp"
+
+#include <boost/lexical_cast.hpp>
+
+namespace ndn {
+
+static const name::Component KEYWORD_PA_COMP = "20025041"_block;
+
+PrefixAnnouncement::PrefixAnnouncement() = default;
+
+PrefixAnnouncement::PrefixAnnouncement(Data data)
+  : m_data(std::move(data))
+{
+  if (m_data->getContentType() != tlv::ContentType_PrefixAnn) {
+    BOOST_THROW_EXCEPTION(Error("Data is not a prefix announcement: ContentType is " +
+                                boost::lexical_cast<std::string>(m_data->getContentType())));
+  }
+
+  const Name& dataName = m_data->getName();
+  if (dataName.size() < 3 || dataName[-3] != KEYWORD_PA_COMP ||
+      !dataName[-2].isVersion() || !dataName[-1].isSegment()) {
+    BOOST_THROW_EXCEPTION(Error("Data is not a prefix announcement: wrong name structure"));
+  }
+  m_announcedName = dataName.getPrefix(-3);
+
+  const Block& payload = m_data->getContent();
+  payload.parse();
+
+  m_expiration = time::milliseconds(readNonNegativeInteger(payload.get(tlv::nfd::ExpirationPeriod)));
+
+  auto validityElement = payload.find(tlv::ValidityPeriod);
+  if (validityElement != payload.elements_end()) {
+    m_validity.emplace(*validityElement);
+  }
+
+  for (const Block& element : payload.elements()) {
+    if (element.type() != tlv::nfd::ExpirationPeriod && element.type() != tlv::ValidityPeriod &&
+        tlv::isCriticalType(element.type())) {
+      BOOST_THROW_EXCEPTION(Error("unrecognized element of critical type " +
+                                  to_string(element.type())));
+    }
+  }
+}
+
+const Data&
+PrefixAnnouncement::toData(KeyChain& keyChain, const ndn::security::SigningInfo& si,
+                           optional<uint64_t> version) const
+{
+  if (!m_data) {
+    Name dataName = m_announcedName;
+    dataName.append(KEYWORD_PA_COMP);
+    dataName.appendVersion(version.value_or(time::toUnixTimestamp(time::system_clock::now()).count()));
+    dataName.appendSegment(0);
+    m_data.emplace(dataName);
+
+    Block content(tlv::Content);
+    content.push_back(makeNonNegativeIntegerBlock(tlv::nfd::ExpirationPeriod,
+                                                  m_expiration.count()));
+    if (m_validity) {
+      content.push_back(m_validity->wireEncode());
+    }
+    content.encode();
+    m_data->setContent(content);
+
+    keyChain.sign(*m_data, si);
+  }
+  return *m_data;
+}
+
+PrefixAnnouncement&
+PrefixAnnouncement::setAnnouncedName(Name name)
+{
+  m_data.reset();
+  m_announcedName = std::move(name);
+  return *this;
+}
+
+PrefixAnnouncement&
+PrefixAnnouncement::setExpiration(time::milliseconds expiration)
+{
+  if (expiration < 0_ms) {
+    BOOST_THROW_EXCEPTION(std::invalid_argument("expiration period is negative"));
+  }
+  m_data.reset();
+  m_expiration = expiration;
+  return *this;
+}
+
+PrefixAnnouncement&
+PrefixAnnouncement::setValidityPeriod(optional<security::ValidityPeriod> validity)
+{
+  m_data.reset();
+  m_validity = std::move(validity);
+  return *this;
+}
+
+} // namespace ndn