libgit2_wasm

This project was developed as part of a bachelor's thesis and explores the practical limitations of compiling native C libraries to WebAssembly (WASM). As a case study, the Git library libgit2 is compiled to WASM using Emscripten and executed in the browser.

The project demonstrates:

• compiling a non-trivial C library to WebAssembly
• interacting with the library from JavaScript
• using OPFS (Origin Private File System)
• running WebAssembly with pthreads in a browser environment

---

Requirements

• Emscripten SDK (emsdk) installed and activated
• CMake
• Make
• Node.js (for the local development server)
• A modern browser supporting:
  • WebAssembly threads
  • SharedArrayBuffer
  • OPFS

The project requires cross-origin isolation (COOP/COEP) and therefore must be accessed through the provided server.

---

Build and Run

Building and running the project consists of two steps.

1. Set the libgit2 source path

The path to the libgit2 source directory must be provided via an environment variable. This directory must contain CMakeLists.txt.

PowerShell (Windows):

$env:LIB_ROOT="C:\path\to\libgit2"

2. Build and start the project

To run using Webassembly:

PowerShell (Windows):

make run

1. Build libgit2 for WebAssembly using Emscripten

2. Link the library against the project’s C/WASM interface

3. Compile the final WebAssembly and JavaScript glue code

4. Start a local Express server at http://localhost:8080

To run natively: PowerShell (Windows):

make native

1. Build libgit2 using GCC

2. Link the library against the Projects native abstraction and compile to an executable

Project structure

project-root/
│
├─ src/
│  ├─ wasm/
│  │  └─ libgit2_wasm.c        # C ↔ WASM interface layer
│  │
│  ├─ js/
│  │  │
│  │  ├─ opfs/                 # OPFS file handling
│  │  │  └─ opfsStorage.js
│  │  │
│  │  ├─ benchmarkWorker.js    # Worker thread used for benchmarking
│  │  │ 
│  │  ├─ config.js             # configuration for main.js
│  │  │ 
│  │  └─ main.js               # Application entry point
│  │
│  └─ index.html
│
├─ server/
│  └─ server.js                # Express server (COOP/COEP enabled)
│
├─ Makefile
├─ package.json
└─ README.md