Switch to std::filesystem

Change-Id: I61a4b4562b3c7fabefb07dced580d2b20d7b6d78
diff --git a/src/detail/ca-sqlite.cpp b/src/detail/ca-sqlite.cpp
index 809f91f..ca4458d 100644
--- a/src/detail/ca-sqlite.cpp
+++ b/src/detail/ca-sqlite.cpp
@@ -25,10 +25,10 @@
 #include <ndn-cxx/security/validation-policy.hpp>
 #include <ndn-cxx/util/sqlite3-statement.hpp>
 
-#include <boost/filesystem/operations.hpp>
-#include <boost/filesystem/path.hpp>
 #include <boost/property_tree/json_parser.hpp>
 
+#include <filesystem>
+
 namespace ndncert::ca {
 
 using ndn::util::Sqlite3Statement;
@@ -80,21 +80,21 @@
   : CaStorage()
 {
   // Determine the path of sqlite db
-  boost::filesystem::path dbDir;
+  std::filesystem::path dbDir;
   if (!path.empty()) {
-    dbDir = boost::filesystem::path(path);
+    dbDir = std::filesystem::path(path);
   }
   else {
     std::string dbName = caName.toUri();
     std::replace(dbName.begin(), dbName.end(), '/', '_');
     dbName += ".db";
     if (getenv("HOME") != nullptr) {
-      dbDir = boost::filesystem::path(getenv("HOME")) / ".ndncert";
+      dbDir = std::filesystem::path(getenv("HOME")) / ".ndncert";
     }
     else {
-      dbDir = boost::filesystem::current_path() / ".ndncert";
+      dbDir = std::filesystem::current_path() / ".ndncert";
     }
-    boost::filesystem::create_directories(dbDir);
+    std::filesystem::create_directories(dbDir);
     dbDir /= dbName;
   }