Fix State
Change-Id: Ifced47b044cfd994eeaf53991f516ef702dd8eaa
diff --git a/src/state.hpp b/src/state.hpp
new file mode 100644
index 0000000..4fa82e9
--- /dev/null
+++ b/src/state.hpp
@@ -0,0 +1,127 @@
+/* -*- Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil -*- */
+/*
+ * Copyright (c) 2012-2014 University of California, Los Angeles
+ *
+ * This file is part of ChronoSync, synchronization library for distributed realtime
+ * applications for NDN.
+ *
+ * ChronoSync 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.
+ *
+ * ChronoSync 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
+ * ChronoSync, e.g., in COPYING.md file. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * @author Zhenkai Zhu <http://irl.cs.ucla.edu/~zhenkai/>
+ * @author Chaoyi Bian <bcy@pku.edu.cn>
+ * @author Alexander Afanasyev <http://lasr.cs.ucla.edu/afanasyev/index.html>
+ * @author Yingdi Yu <yingdi@cs.ucla.edu>
+ */
+
+#ifndef CHRONOSYNC_STATE_HPP
+#define CHRONOSYNC_STATE_HPP
+
+#include "tlv.hpp"
+#include "leaf-container.hpp"
+#include <ndn-cxx/util/digest.hpp>
+
+namespace chronosync {
+
+class State;
+typedef shared_ptr<State> StatePtr;
+typedef shared_ptr<const State> ConstStatePtr;
+
+/**
+ * @brief Abstraction of state tree.
+ *
+ * State is used to represent sync tree, it is also the base class of DiffState,
+ * which represent the diff between two states. Due to the second usage, State
+ * should be copyable.
+ */
+class State
+{
+public:
+ class Error : public std::runtime_error
+ {
+ public:
+ explicit
+ Error(const std::string& what)
+ : std::runtime_error(what)
+ {
+ }
+ };
+
+ virtual
+ ~State();
+
+ /**
+ * @brief Add or update leaf to the sync tree
+ *
+ * @param info session name of the leaf
+ * @param seq sequence number of the leaf
+ * @return 3-tuple (isInserted, isUpdated, oldSeqNo)
+ */
+ boost::tuple<bool, bool, SeqNo>
+ update(const Name& info, const SeqNo& seq);
+
+ /**
+ * @brief Get state leaves
+ */
+ const LeafContainer&
+ getLeaves() const
+ {
+ return m_leaves;
+ }
+
+ ndn::ConstBufferPtr
+ getRootDigest() const;
+
+ /**
+ * @brief Reset the sync tree, remove all state leaves
+ */
+ void
+ reset();
+
+ /**
+ * @brief Combine `this' state and the supplied state
+ *
+ * The combination result contains all leaves in two states.
+ * When leaves conflict, keep the one with largest seq.
+ *
+ * @param state another state to combine with
+ * @return Combined state
+ */
+ State&
+ operator+=(const State& state);
+
+ /**
+ * @brief Encode to a wire format
+ */
+ const Block&
+ wireEncode() const;
+
+ /**
+ * @brief Decode from the wire format
+ */
+ void
+ wireDecode(const Block& wire);
+
+protected:
+ template<bool T>
+ size_t
+ wireEncode(ndn::EncodingImpl<T>& block) const;
+
+protected:
+ LeafContainer m_leaves;
+
+ mutable ndn::util::Sha256 m_digest;
+ mutable Block m_wire;
+};
+
+} // namespace chronosync
+
+#endif // CHRONOSYNC_STATE_HPP