link: add Link abstraction
Change-Id: I1e4bafe8559ef87135de6cb6f209fc94dfa231a3
Refs: #2587
diff --git a/src/link.hpp b/src/link.hpp
new file mode 100644
index 0000000..3ccb7a3
--- /dev/null
+++ b/src/link.hpp
@@ -0,0 +1,161 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (c) 2013-2015 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.
+ */
+
+#ifndef NDN_LINK_HPP
+#define NDN_LINK_HPP
+
+#include "data.hpp"
+#include <set>
+
+namespace ndn {
+
+const size_t INVALID_SELECTED_DELEGATION_INDEX = std::numeric_limits<size_t>::max();
+
+/** @brief represents a Link instance
+ */
+class Link : public Data
+{
+public:
+ class Error : public Data::Error
+ {
+ public:
+ explicit
+ Error(const std::string& what)
+ : Data::Error(what)
+ {
+ }
+ };
+
+ // The ordering is based on the preference number and needs to be preserved
+ typedef std::set<std::pair<uint32_t, Name>> DelegationSet;
+
+ /**
+ * @brief Create an empty Link object
+ *
+ * Note that in certain contexts that use Link::shared_from_this(), Link must be
+ * created using `make_shared`:
+ *
+ * shared_ptr<Link> linkObject = make_shared<Link>();
+ *
+ * Otherwise, Link::shared_from_this() will throw std::bad_weak_ptr.
+ */
+ Link() = default;
+
+ /**
+ * @brief Create a Link object from a Block
+ *
+ * Note that in certain contexts that use Link::shared_from_this(), Link must be
+ * created using `make_shared`:
+ *
+ * shared_ptr<Link> linkObject = make_shared<Link>(block);
+ *
+ * Otherwise, Link::shared_from_this() will throw std::bad_weak_ptr.
+ */
+ explicit
+ Link(const Block& block);
+
+ /**
+ * @brief Create a Link object with the given name
+ *
+ * @param name A reference to the name of the redirected namespace
+ *
+ * Note that in certain contexts that use Link::shared_from_this(), Link must be
+ * created using `make_shared`:
+ *
+ * shared_ptr<Link> link = make_shared<Link>(name);
+ *
+ * Otherwise, Link::shared_from_this() will throw std::bad_weak_ptr.
+ */
+ explicit
+ Link(const Name& name);
+
+ /**
+ * @brief Create a Link object with the given name and pairs of <Preference, Name>
+ *
+ * @param name A reference to the name of the redirected namespace
+ * @param links A reference to the list of pairs of the redirected namespace
+ * along with its priority
+ *
+ * Note that in certain contexts that use Link::shared_from_this(), Link must be
+ * created using `make_shared`:
+ *
+ * shared_ptr<Link> link = make_shared<Link>(name, links);
+ *
+ * Otherwise, Link::shared_from_this() will throw std::bad_weak_ptr.
+ */
+ Link(const Name& name, std::initializer_list<std::pair<uint32_t, Name>> links);
+
+ /**
+ * @brief Add a delegation in the format of <Name, Preference>
+ * @param preference The preference of the delegation to be added
+ * @param name The name of the delegation to be added
+ * @note If a delegation with @p name exists, its preference will be updated
+ */
+ void
+ addDelegation(uint32_t preference, const Name& name);
+
+ /**
+ * @brief Remove a delegation whose name is @p name
+ * @param name The name of the delegation to be removed
+ * @return true if delegation is removed, otherwise false
+ */
+ bool
+ removeDelegation(const Name& name);
+
+ /**
+ * @brief Get the pairs of <Name, Preference>
+ * @return a set of delegations
+ */
+ const DelegationSet&
+ getDelegations() const;
+
+ /**
+ * @brief Decode from the wire format
+ */
+ void
+ wireDecode(const Block& wire);
+
+protected:
+ /** \brief prepend Link object as a Content block to the encoder
+ *
+ * The outermost Content element is not part of Link object structure.
+ */
+ template<encoding::Tag TAG>
+ size_t
+ encodeContent(EncodingImpl<TAG>& encoder) const;
+
+ void
+ encodeContent();
+
+ void
+ decodeContent();
+
+private:
+ bool
+ removeDelegationNoEncode(const Name& name);
+
+private:
+ DelegationSet m_delegations;
+};
+
+} // namespace ndn
+
+#endif // NDN_LINK_HPP