split configuration into pieces

Change-Id: I3039a3e15d9637e05b0f9678a7141258fb49e983
diff --git a/src/detail/ca-configuration.cpp b/src/detail/ca-configuration.cpp
new file mode 100644
index 0000000..b88352b
--- /dev/null
+++ b/src/detail/ca-configuration.cpp
@@ -0,0 +1,82 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (c) 2017-2020, Regents of the University of California.
+ *
+ * This file is part of ndncert, a certificate management system based on NDN.
+ *
+ * ndncert 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.
+ *
+ * ndncert 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 copies of the GNU General Public License along with
+ * ndncert, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * See AUTHORS.md for complete list of ndncert authors and contributors.
+ */
+
+#include "detail/ca-configuration.hpp"
+#include "identity-challenge/challenge-module.hpp"
+#include "name-assignment/assignment-func.hpp"
+#include <ndn-cxx/util/io.hpp>
+#include <boost/filesystem.hpp>
+
+namespace ndn {
+namespace ndncert {
+namespace ca {
+
+void
+CaConfig::load(const std::string& fileName)
+{
+  JsonSection configJson;
+  try {
+    boost::property_tree::read_json(fileName, configJson);
+  }
+  catch (const std::exception& error) {
+    NDN_THROW(std::runtime_error("Failed to parse configuration file " + fileName + ", " + error.what()));
+  }
+  if (configJson.begin() == configJson.end()) {
+    NDN_THROW(std::runtime_error("No JSON configuration found in file: " + fileName));
+  }
+  m_caItem.parse(configJson);
+  if (m_caItem.m_supportedChallenges.size() == 0) {
+    NDN_THROW(std::runtime_error("At least one challenge should be specified."));
+  }
+  // parse redirection section if appears
+  m_redirection = nullopt;
+  auto redirectionItems = configJson.get_child_optional(CONFIG_REDIRECTION);
+  if (redirectionItems) {
+    for (const auto& item : *redirectionItems) {
+      auto caPrefixStr = item.second.get(CONFIG_CA_PREFIX, "");
+      auto caCertStr = item.second.get(CONFIG_CERTIFICATE, "");
+      if (caCertStr == "") {
+        NDN_THROW(std::runtime_error("Redirect-to item's ca-prefix or certificate cannot be empty."));
+      }
+      std::istringstream ss(caCertStr);
+      auto caCert = io::load<security::Certificate>(ss);
+      if (!m_redirection) {
+        m_redirection = std::vector<std::shared_ptr<security::Certificate>>();
+      }
+      m_redirection->push_back(caCert);
+    }
+  }
+  // parse name assignment if appears
+  m_nameAssignmentFuncs.clear();
+  auto nameAssignmentItems = configJson.get_child_optional(CONFIG_NAME_ASSIGNMENT);
+  if (nameAssignmentItems) {
+    for (const auto& item : *nameAssignmentItems) {
+      auto func = NameAssignmentFunc::createNameAssignmentFunc(item.first, item.second.data());
+      if (func == nullptr) {
+        NDN_THROW(std::runtime_error("Error on creating name assignment function"));
+      }
+      m_nameAssignmentFuncs.push_back(std::move(func));
+    }
+  }
+}
+
+} // namespace ca
+} // namespace ndncert
+} // namespace ndn