| AccessPermissionManager | Implements access permission control of filesystem resources. |
| CredentialManager | Provides intuitive interface for storage and retrival for user credentials. |
| FilesystemAccessInterface | Abstraction for Filesystem Access. |
| FilesystemUtility | Provides useful functionalities to simplify filesystem operations. |
| SessionManager | Manage session states for web server. |
| SQLiteDatabaseConnection | Modern C++ interface for SQLite. |