mozjs-c-api

Unofficial minimal C API for the Spidermonkey JavaScript VM

Purpose

Spidermonkey currently has a large, complicated, poorly documented, continually evolving, C++ API (known as JSAPI). Whilst this approach to API design and implementation may work for Mozilla, it doesn't work well for me. I would like to be able to target a small, stable API. I would like to be able to generate a Spidermonkey shared library that has a stable API/ABI (ie both a stable source and binary interface) and is trivially simple to link against. The purpose of this repo is to design and implement such an API.

Current status

This repo currently contains an absolutely minimal viable product (MVP) C API built on top of Spidermonkey 52 ESR. I'm still in the design process so the API/ABI will likely evolve. Once I have figured out a good design I will freeze the API/ABI.

When I say MVP I really mean it. We only have 3 functions (all return a status code with 0 for success):

• int mjs_init(void) initialise the VM. Must only be called once during your program (I may eventually loosen this requirement to once per thread). This function creates and initialises a single copy of the VM in memory. The VM is tighly bound to the thread on which is was created, you must only call in to the VM from that thread for the whole duration of your program.
• int mjs_evaluate(const char * script) run a script in the VM. The variable script is the actual source code of the script (not a file name). Must only be called from the same thread as mjs_init was called.
• int mjs_shutdown(void) shutdown the VM (must only be called from the same thread as mjs_init was called from)

To use the API include mozjs-c.h and dynamically link to libmozjs-c.so (see example.c and mk-example for an example).

Building

See BUILDING.txt for full instructions