Architecture

ROM Validator is a .NET 10 WPF application. The code is organized into a small UI layer, a service layer, and plain data models.

High-level structure 

App (composition root)
├── MainWindow
│   ├── ValidatePage        (validation workflow)
│   ├── GenerateDatPage     (DAT generation workflow)
│   ├── AboutWindow
│   └── DuplicateFilesWindow
└── Services
    ├── HashCalculator      hashing of files and archives
    ├── ArchiveService      SharpCompress read/extract/create helpers
    ├── SevenZipProcess     bundled 7za fallback
    ├── TempDirectoryHelper temp folders, disk space, cleanup retries
    ├── LoggerService       Serilog facade
    ├── BugReportService    bug report API client
    ├── BugReportSink       Serilog sink that forwards Warning+
    ├── ApplicationStatsService  anonymous usage stats
    ├── GitHubVersionChecker     update check
    ├── ScreenshotService   F8 screenshots
    ├── AppPaths            application data folders
    └── FileSystemHelper    shared error classification

Composition root

App creates the long-lived services (BugReportService, GitHubVersionChecker, ApplicationStatsService), configures Serilog, registers global exception handlers and the application-wide F8 shortcut, and disposes everything on exit. MainWindow receives the services through the App instance so that only one HTTP client per service exists.

Service layer

Service Responsibility
HashCalculator Computes CRC32/MD5/SHA-1/SHA-256 for files and archive entries. Streams data, retries locked files, detects disk-full and CRC errors
ArchiveService SharpCompress wrappers: list entries, total size, extract, create zip and 7z
SevenZipProcess Runs the bundled 7za.exe / 7za_arm64.exe as a fallback for extraction and creation
TempDirectoryHelper Creates temp folders, tracks them, deletes with retries and background retry timer, estimates archive sizes
LoggerService Facade over Serilog; never throws; used by every component
BugReportService Builds and sends bug reports (environment/error/exception sections)
BugReportSink Serilog sink forwarding Warning+ events; filters its own components and allows one in-flight report
GitHubVersionChecker Queries the latest GitHub release and compares versions
ScreenshotService Captures the active window to PNG
AppPaths Resolves the AppData, logs and screenshot folders

Models

  • Models/NoIntro - Datafile, Header, Game, Rom: the No-Intro XML datafile model used for reading and writing DAT files.
  • Models/GameFile - hashing result for one file or archive entry.
  • Models/DuplicateGroup - a group of files sharing a hash.
  • Models/GitHubRelease, Models/GitHubAsset - GitHub API contract.
  • Models/BugReportPayload - bug report API contract.

Interfaces

Interfaces/ contains the abstractions used for dependency injection and testing: IBugReportService, IApplicationStatsService and IGitHubVersionChecker.

Threading

  • File validation is intentionally sequential to avoid race conditions when moving files to the shared _success / _fail / _duplicate folders.
  • Hashing of a single file/entry is asynchronous and streams data with a 64 KB buffer.
  • UI updates are marshalled to the dispatcher. Progress and status updates are fire-and-forget with logging on failure.
  • Cancellation uses CancellationTokenSource per operation, plus a global token source that is cancelled when the application exits.

Logging pipeline 

LoggerService ──► Serilog
                    ├── Debug sink   (Visual Studio output)
                    ├── File sink    (%LOCALAPPDATA%\ROM Validator\Logs, 7 days)
                    └── BugReportSink (Warning+, one report in flight)

Environmental conditions (network failures, corrupt user files, locked files, cloud placeholders) are logged at Information level so they are not forwarded as bug reports. Warnings and errors indicate genuine application anomalies.

Error handling strategy

  • Every public entry point wraps work in try/catch and logs through LoggerService.
  • User-environment failures (corrupt files, access denied, disk full, cloud placeholders) are surfaced as per-file results with an explanatory message instead of aborting the run.
  • Global handlers capture unhandled dispatcher, AppDomain and task exceptions, log them and show a friendly dialog.

Archive stack

  1. SharpCompress 0.50.4 is the primary reader/writer for zip and 7z, and the reader for rar.
  2. 7za 26.03 (bundled, architecture-matched) is the fallback when SharpCompress cannot read or create an archive.
  3. RAR archives are converted to zip when an internal rename is required, because RAR creation is not supported.