security: define new abstraction for identity, key, and certificate

Refs: #2451

Change-Id: I85dc7e0508bf10e2b73b0e9793dfc8e909e1a6e3
diff --git a/src/security/key-container.hpp b/src/security/key-container.hpp
new file mode 100644
index 0000000..9799d03
--- /dev/null
+++ b/src/security/key-container.hpp
@@ -0,0 +1,99 @@
+/* -*- 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_SECURITY_KEY_CONTAINER_HPP
+#define NDN_SECURITY_KEY_CONTAINER_HPP
+
+#include <set>
+#include "key.hpp"
+
+namespace ndn {
+namespace security {
+
+class PibImpl;
+
+/// @brief A handler to search or enumerate keys of an identity.
+class KeyContainer
+{
+public:
+  class const_iterator
+  {
+  public:
+    friend class KeyContainer;
+
+  public:
+    Key
+    operator*();
+
+    const_iterator&
+    operator++();
+
+    const_iterator
+    operator++(int);
+
+    bool
+    operator==(const const_iterator& other);
+
+    bool
+    operator!=(const const_iterator& other);
+
+  private:
+    const_iterator(const Name& identity,
+                   std::set<name::Component>::const_iterator it,
+                   shared_ptr<PibImpl> impl);
+
+  private:
+    Name m_identity;
+    std::set<name::Component>::const_iterator m_it;
+    shared_ptr<PibImpl> m_impl;
+  };
+
+  typedef const_iterator iterator;
+
+public:
+  KeyContainer();
+
+  KeyContainer(const Name& identity,
+               std::set<name::Component>&& keyIds,
+               shared_ptr<PibImpl> impl);
+
+  const_iterator
+  begin() const;
+
+  const_iterator
+  end() const;
+
+  const_iterator
+  find(const name::Component& keyId) const;
+
+  size_t
+  size() const;
+
+private:
+  Name m_identity;
+  std::set<name::Component> m_keyIds;
+  shared_ptr<PibImpl> m_impl;
+};
+
+} // namespace security
+} // namespace ndn
+
+#endif // NDN_SECURITY_KEY_CONTAINER_HPP