db-mgr: add Zone lookup/insert/remove

Change-Id: I9c0beab970f4508ba6523d7c2a3280fecbdd6cc1
diff --git a/src/db-mgr.hpp b/src/db-mgr.hpp
new file mode 100644
index 0000000..26041c6
--- /dev/null
+++ b/src/db-mgr.hpp
@@ -0,0 +1,169 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (c) 2014, Regents of the University of California.
+ *
+ * This file is part of NDNS (Named Data Networking Domain Name Service).
+ * See AUTHORS.md for complete list of NDNS authors and contributors.
+ *
+ * NDNS 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.
+ *
+ * NDNS 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
+ * NDNS, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef NDNS_DB_MGR_HPP
+#define NDNS_DB_MGR_HPP
+
+#include "config.hpp"
+#include "zone.hpp"
+
+#include <ndn-cxx/common.hpp>
+#include <sqlite3.h>
+
+namespace ndn {
+namespace ndns {
+
+#define DEFINE_ERROR(Name, Base)                \
+class Name : public Base                        \
+{                                               \
+ public:                                        \
+  explicit                                      \
+  Name(const std::string& what)                 \
+    : Base(what)                                \
+  {                                             \
+  }                                             \
+};
+
+/**
+ * @brief Database Manager, which provides some common DB functionalities
+ */
+class DbMgr : noncopyable
+{
+public:
+  /**
+   * @brief The Database Status
+   */
+  enum DbStatus {
+    DB_CONNECTED,
+    DB_CLOSED,
+    DB_ERROR
+  };
+
+  DEFINE_ERROR(Error, std::runtime_error);
+  DEFINE_ERROR(PrepareError, Error);
+  DEFINE_ERROR(ExecuteError, Error);
+
+public:
+  /**
+   * @brief constructor
+   */
+  explicit
+  DbMgr(const std::string& dbFile = DEFAULT_CONFIG_PATH "/" "ndns.conf");
+
+  /**
+   * @brief destructor
+   */
+  ~DbMgr();
+
+  /**
+   * @brief connect to the database
+   */
+  void
+  open();
+
+  /**
+   * @brief close the database connection
+   */
+  void
+  close();
+
+  /**
+   * @brief get error message
+   *
+   * only valid when some db-related error happens,
+   * such as db file does not exist, wrong SQL, etc
+   */
+  const std::string&
+  getErr() const
+  {
+    return m_err;
+  }
+
+  /**
+   * @brief get Database connection status
+   */
+  DbStatus
+  getStatus() const
+  {
+    return m_status;
+  }
+
+public: // Zone manipulation
+  DEFINE_ERROR(ZoneError, Error);
+
+  /**
+   * @brief lookup the zone by name, fill the m_id and m_ttl
+   * @post whatever the previous id is
+   * @return true if the record exist
+   */
+  bool
+  lookup(Zone& zone);
+
+  /**
+   * @brief remove the zone
+   * @pre m_zone.getId() > 0
+   * @post m_zone.getId() == 0
+   */
+  void
+  remove(Zone& zone);
+
+  /**
+   * @brief insert the m_zone to the database, and set the zone's id.
+   * If the zone is already in the db, handle the exception without leaving it to upper level,
+   * meanwhile, set the zone's id too.
+   * @pre m_zone.getId() == 0
+   * @post m_zone.getId() > 0
+   */
+  void
+  insert(Zone& zone);
+
+private:
+  /**
+   * @brief set error message
+   *
+   * only valid when some db-related error happens,
+   * such as db file does not exist, wrong SQL, etc
+   */
+  void
+  setErr(const std::string& err)
+  {
+    this->m_err = err;
+  }
+
+  /**
+   * @brief set Database connection status
+   */
+  void
+  setStatus(DbStatus status)
+  {
+    this->m_status = status;
+  }
+
+private:
+  std::string m_dbFile;
+  sqlite3* m_conn;
+
+  std::string m_err;
+  DbStatus m_status;
+};
+
+} // namespace ndns
+} // namespace ndn
+
+#endif // NDNS_DB_MGR_HPP