QuickFolderSize

日本語版 README_jp.md

Windows desktop app that shows how much space folders and files use on local drives. Scan a path, browse the result as a sortable tree with ratio bars, and export a Markdown report.

Version: v1.0.0

Implementation: C++17 (MinGW-w64 / g++) + WebView2. The UI is HTML/CSS/vanilla JS hosted in a native WebView2 window. There is no Python or Qt runtime in the shipped app.

Using the binary release

If you only want to run the app, download the ZIP from GitHub Releases.

• Latest releases
• v1.0.0
• Direct download of QuickFolderSize-binary.zip

Extract every file into the same folder and run QuickFolderSize.exe.

• QuickFolderSize.exe — app
• engine_x64.dll — standalone scan-engine DLL
• WebView2Loader.dll — WebView2 loader
• index.html — bundled UI
• readme.txt / readme-jp.txt — usage notes
• LICENSE.txt / LICENSE_jp.txt — MIT License

Windows 11 already includes WebView2 Runtime. On some Windows 10 / LTSC / Server machines, install Microsoft Edge WebView2 Runtime (Evergreen).

Updates go through pull requests to main. Pushing a v* tag (or running the Release workflow) rebuilds the ZIP and attaches it to the GitHub Release.

Features

• Recursive folder scan with sizes, recursive file counts, and last-modified times
• Background scan (UI stays responsive)
• Full-depth parallel scan: one shared 32-worker pool, non-blocking fan-out, so deep trees stay parallel
• Incremental tree updates as each top-level child finishes
• Placeholder row for the first level as soon as a scan starts
• Elapsed scan time in the left-bottom card, updated every 0.2 s (0.00s … 12.34s)
• Drive usage on the address bar (C:\ 150.3 GB / 512.0 GB)
• Left nav pane: drives and lazy-expanded folders
• Clicking a path already inside the current scan jumps the tree without rescanning
• NTFS junctions / mount points / reparse points are skipped (no cycles, no other volumes)
• mtime cache: unchanged directories skip re-enumeration on rescan (FILETIME compare)
• Markdown folder-size report
• Japanese / English toggle (menu bar, top right). Menus, headers, dialogs, and reports switch immediately

UI

Dark glassmorphism theme (same family as QuickDiskBench):

• Near-black canvas (#0a0c10) with soft blue / purple / cyan radial glows
• Frosted glass cards (backdrop-filter blur, translucent #10141c)
• Accent cyan #00f0ff and blue #3b82f6 on the Scan button, hover states, and size bars
• Inaccessible folders shown in red (#ef4444)
• System fonts only (Segoe UI / Yu Gothic UI) so the UI works offline — no CDN

Layout:

┌─ File / Help ──────────────────────────────────── [🌐 English] ─┐
├─ [C:\ 150.3 GB / 512.0 GB]  [path input]  [Scan] ───────────────┤
├─ Drives / folders (lazy) ─┬─ Name | Size | Ratio | Files | Date ┤
│                            │  📁 Windows   40.1 GB  ████  62.3% │
│  Scan Time        2.34s    │  📄 pagefile  16.0 GB  ██    24.9% │
└────────────────────────────┴────────────────────────────────────┘

• File — Open Folder (Ctrl+O), Rescan (F5), Export Report (Ctrl+Shift+S), Exit (Ctrl+Q)
• Help — About
• Language button — Japanese ⇔ English
• Address bar — drive capacity, path, Scan (Enter also starts a scan)
• Left nav — drive list; expand on demand
• Scan Time — live elapsed time while scanning, final time when done
• Result tree — click a column header to sort; ▶ / ▼ to expand rows

Run the built app

dist\binary\QuickFolderSize.exe

Keep these files in the same folder:

File	Role
QuickFolderSize.exe	Native host + scan engine (statically linked)
engine_x64.dll	Standalone scan-engine DLL (the EXE does not load this at runtime)
WebView2Loader.dll	WebView2 loader
index.html	Bundled UI (CSS/JS inlined)

Windows 11 already includes Microsoft Edge WebView2 Runtime. On some Windows 10 / LTSC / Server machines, install the Evergreen Runtime if the window fails to open. See QuickFolderSize_debug.log next to the EXE if startup fails.

Distribution notes for end users: dist/documents/readme.txt (English) and dist/documents/readme-jp.txt (Japanese).

Build from source

winget install --id BrechtSanders.WinLibs.MCF.UCRT --exact --source winget
# Place WebView2 SDK headers/loader at C:\tools\webview2\build\native\
#   include\WebView2.h  and  x64\WebView2Loader.dll

cd QuickFolderSize
build.bat
# → dist\binary\QuickFolderSize.exe

build.bat runs python build_native.py. That script finds WinLibs g++, bundles HTML, compiles engine_x64.dll and the GUI EXE (-mwindows, engine statically linked), and copies WebView2Loader.dll.

Details: document/environment.md.

Keyboard shortcuts

Shortcut	Action
Ctrl+O	Open folder dialog
F5	Rescan
Ctrl+Shift+S	Export Markdown report
Ctrl+Q	Exit
Enter in the path box	Scan

Requirements

• Windows 10 / 11 (64-bit)
• Microsoft Edge WebView2 Runtime
• To build: MinGW-w64 g++ (WinLibs MCF/UCRT), WebView2 SDK, Python 3 (for the build scripts only)

No third-party C++ libraries. The frontend is vanilla JS.

Repository layout

QuickFolderSize/
├── core/native/          Scan engine + WebView2 host (C++)
├── templates/            Dev HTML
├── static/css|js         Dev CSS / JS
├── python/               Phase 1 Python/PyQt6 prototype (reference only)
├── document/             Spec, environment, about
├── dist/binary/          Build output (not in git)
├── dist/documents/       Packaged readme / history
├── build_native.py       Native build
├── bundle_html.py        Inlines CSS/JS into one HTML file
└── build.bat

Docs

• Spec → document/spec.md
• Build environment → document/environment.md
• About / version → document/about.md
• Japanese README → README_jp.md

Concept

I built this in a pinch: the SSD on my work PC was almost full.

Export the report and feed it to an AI agent — it gives surprisingly useful advice about what to clean up.

Similar tools already exist, but none of them felt right for me, so I wrote one from scratch. After a lot of trial and error with different scan conditions, it runs reasonably fast.

Author

GitHub: maktak-105