About

a-files-updater is the Streamlabs Desktop auto-updater — a Windows C++ application (slobs-updater.exe) that handles updating Streamlabs Desktop (SLOBS).

How this works

Core flow:

1. Launched by the main app (not directly by users) with CLI parameters specifying the current version, app directory, and executables to run
2. Prompts the user to accept or defer the update (shows version/changelog details from a JSON file)
3. Checks for blocking processes — if apps are using the virtual webcam driver or otherwise locking files, it shows them and lets the user close them or force-kill them
4. Checks disk space — warns if less than 2GB is free before downloading
5. Downloads files — multi-threaded downloader with a real-time progress bar showing files done, total count, and MB/s bandwidth
6. Installs packages — can download and silently run installers (e.g., VC++ Redistributable) as prerequisites
7. Copies updated files — replaces the old app files
8. Secures the graphics hook directory — hardens permissions on %ProgramData%\obs-studio-hook after every update (see below)
9. Uses trusted update storage — stages downloads and rollback copies below an Administrators-owned %ProgramData%\slobs-updater directory and verifies its owner, DACL, reparse status, and ancestors before every run
10. Launches the updated app — or falls back to launching the old app if the update failed

Notable details:

• Built with C++17, uses Boost (locale, iostreams, asio, beast), OpenSSL, and zlib
• Localized into ~25 languages via Boost.locale + gettext .po files embedded as Windows resources
• Has a custom Win32 GUI with Streamlabs dark-theme styling (dark background, teal/green accent color)
• Supports both interactive and non-interactive (silent/automated) modes
• Includes crash reporting (crash-reporter.cc) and an error state file for the parent app to inspect
• DPI-aware — responds to WM_DPICHANGED and scales all UI elements accordingly
• Removes the current updater run after normal completion, prunes abandoned payload runs after 24 hours while skipping active runs, and makes failed-rollback originals eligible for pruning after 7 days
• Retries leaf-only cleanup of quarantined updater roots on later runs; non-empty attacker-owned trees are never recursively traversed and remain until emptied

How to build

As easy as:

set PATH=%PATH%;C:\Program Files\7-Zip\

ci\localization_prepare_binaries.cmd

cmake -H"." -B"build" -G"Visual Studio 17 2022" -DCMAKE_BUILD_TYPE=RelWithDebInfo -A x64 -DCMAKE_TOOLCHAIN_FILE=%VCPKG_ROOT%/scripts/buildsystems/vcpkg.cmake -DVCPKG_TARGET_TRIPLET=x64-windows-static -DCMAKE_INSTALL_PREFIX="%CD%/build/distribute/a-file-updater"

cmake --build build --target install --config RelWithDebInfo

Dependencies

This project depends on a few third party libraries, all provided by vcpkg (see vcpkg.json):

• OpenSSL 3.x
• zlib
• Boost 1.91.x (compiled: iostreams, system, locale; header-only: asio, beast, algorithm)

These libraries are installed automatically by vcpkg during the CMake configure step (manifest mode), so you need a vcpkg checkout — set VCPKG_ROOT to it (or pass the toolchain path explicitly as shown above).

In order to build, point CMake at a vcpkg checkout via VCPKG_ROOT (or pass -DCMAKE_TOOLCHAIN_FILE directly) as shown above, then run cmake however you want. A C++17 conformant compiler is required. Outside of that, as long as the dependencies are met and compatible, you can use whatever compiler you want.

Localization

Boost.locale lib with a gettext format used for a localization. mo files included in exe by windows resources.

Commands

ci\localization_prepare_binaries.cmd - prepares mo files with current translation

ci\localization_set_translations.cmd - update po files with current strings from source code

Add new language

• Add new lang code into ci\localization_get_tools.cmd and run ci\localization_set_translations.cmd
• Translate lines inside locale\NEW_LANG\LC_MESSAGES\messages.po
• Add new mo file to resources\slobs-updater.rc
• Add it to locales_resources map inside get_messages_callback()
• Prepare binaries ci\localization_prepare_binaries.cmd
• Make a new build
• Do not forget to commit locale\NEW_LANG\LC_MESSAGES\messages.po
• to test set LANG=fr_FR

How to run tests

See How to run Tests