Adding DataProducer class to produce and encrypt data packets.

Change-Id: I147164a1517f1f6f24536959bc572a6d777c15b0
refs: #3016
diff --git a/src/producer-db.cpp b/src/producer-db.cpp
new file mode 100644
index 0000000..c748953
--- /dev/null
+++ b/src/producer-db.cpp
@@ -0,0 +1,151 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (c) 2014-2015,  Regents of the University of California
+ *
+ * This file is part of ndn-group-encrypt (Group-based Encryption Protocol for NDN).
+ * See AUTHORS.md for complete list of ndn-group-encrypt authors and contributors.
+ *
+ * ndn-group-encrypt 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-group-encrypt 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-group-encrypt, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * @author Prashanth Swaminathan <prashanthsw@gmail.com>
+ */
+
+#include "producer-db.hpp"
+
+#include <sqlite3.h>
+#include <boost/filesystem.hpp>
+#include <ndn-cxx/util/sqlite3-statement.hpp>
+#include <ndn-cxx/security/identity-certificate.hpp>
+
+namespace ndn {
+namespace gep {
+
+using util::Sqlite3Statement;
+using time::system_clock;
+
+static const std::string INITIALIZATION =
+  "CREATE TABLE IF NOT EXISTS                         \n"
+  "  contentkeys(                                     \n"
+  "    rowId            INTEGER PRIMARY KEY,          \n"
+  "    timeslot         INTEGER,                      \n"
+  "    key              BLOB NOT NULL                 \n"
+  "  );                                               \n"
+  "CREATE UNIQUE INDEX IF NOT EXISTS                  \n"
+  "   timeslotIndex ON contentkeys(timeslot);         \n";
+
+class ProducerDB::Impl
+{
+public:
+  Impl(const std::string& dbPath)
+  {
+    // open Database
+
+    int result = sqlite3_open_v2(dbPath.c_str(), &m_database,
+                                 SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE,
+#ifdef NDN_CXX_DISABLE_SQLITE3_FS_LOCKING
+                                 "unix-dotfile"
+#else
+                                 nullptr
+#endif
+                                 );
+
+    if (result != SQLITE_OK)
+      BOOST_THROW_EXCEPTION(Error("Producer DB cannot be opened/created: " + dbPath));
+
+    // enable foreign key
+    sqlite3_exec(m_database, "PRAGMA foreign_keys = ON", nullptr, nullptr, nullptr);
+
+    // initialize database specific tables
+    char* errorMessage = nullptr;
+    result = sqlite3_exec(m_database, INITIALIZATION.c_str(), nullptr, nullptr, &errorMessage);
+    if (result != SQLITE_OK && errorMessage != nullptr) {
+      sqlite3_free(errorMessage);
+      BOOST_THROW_EXCEPTION(Error("Producer DB cannot be initialized"));
+    }
+  }
+
+  ~Impl()
+  {
+    sqlite3_close(m_database);
+  }
+
+public:
+  sqlite3* m_database;
+};
+
+ProducerDB::ProducerDB(const std::string& dbPath)
+  : m_impl(new Impl(dbPath))
+{
+}
+
+ProducerDB::~ProducerDB() = default;
+
+static int32_t
+getFixedTimeslot(const system_clock::TimePoint& timeslot) {
+  return (time::toUnixTimestamp(timeslot)).count() / 3600000;
+}
+
+bool
+ProducerDB::hasContentKey(const system_clock::TimePoint& timeslot) const
+{
+  int32_t fixedTimeslot = getFixedTimeslot(timeslot);
+  Sqlite3Statement statement(m_impl->m_database,
+                             "SELECT key FROM contentkeys where timeslot=?");
+  statement.bind(1, fixedTimeslot);
+  return (statement.step() == SQLITE_ROW);
+}
+
+
+Buffer
+ProducerDB::getContentKey(const system_clock::TimePoint& timeslot) const
+{
+  int32_t fixedTimeslot = getFixedTimeslot(timeslot);
+  Sqlite3Statement statement(m_impl->m_database,
+                             "SELECT key FROM contentkeys where timeslot=?");
+  statement.bind(1, fixedTimeslot);
+
+  Buffer result;
+  if (statement.step() == SQLITE_ROW) {
+    result = Buffer(statement.getBlob(0), statement.getSize(0));
+  }
+  else {
+    BOOST_THROW_EXCEPTION(Error("Cannot get the key from database"));
+  }
+  return result;
+}
+
+void
+ProducerDB::addContentKey(const system_clock::TimePoint& timeslot, const Buffer& key)
+{
+  // BOOST_ASSERT(key.length() != 0);
+  int32_t fixedTimeslot = getFixedTimeslot(timeslot);
+  Sqlite3Statement statement(m_impl->m_database,
+                             "INSERT INTO contentkeys (timeslot, key)\
+                              values (?, ?)");
+  statement.bind(1, fixedTimeslot);
+  statement.bind(2, key.buf(), key.size(), SQLITE_TRANSIENT);
+  if (statement.step() != SQLITE_DONE)
+    BOOST_THROW_EXCEPTION(Error("Cannot add the key to database"));
+}
+
+void
+ProducerDB::deleteContentKey(const system_clock::TimePoint& timeslot)
+{
+  int32_t fixedTimeslot = getFixedTimeslot(timeslot);
+  Sqlite3Statement statement(m_impl->m_database,
+                             "DELETE FROM contentkeys WHERE timeslot=?");
+  statement.bind(1, fixedTimeslot);
+  statement.step();
+}
+
+} // namespace gep
+} // namespace ndn