worker.js

import EventEmitter from "events";
import HookEvent from "./hook.js";
import { BareMuxConnection } from "@mercuryworkshop/bare-mux";

/**
 * @typedef {import('./index').default} UVClient
 */

class Workers extends EventEmitter {
	/**
	 *
	 * @param {UVClient} ctx
	 */
	constructor(ctx) {
		super();
		this.ctx = ctx;
		this.window = ctx.window;
		this.Worker = this.window.Worker || {};
		this.Worklet = this.window.Worklet || {};
		this.workletProto = this.Worklet.prototype || {};
		this.workerProto = this.Worker.prototype || {};
		this.postMessage = this.workerProto.postMessage;
		this.terminate = this.workerProto.terminate;
		this.addModule = this.workletProto.addModule;
	}
	overrideWorker() {
		this.ctx.override(
			this.window,
			"Worker",
			(target, that, args) => {
				if (!args.length) return new target(...args);
				let [url, options = {}] = args;

				const event = new HookEvent({ url, options }, target, that);
				this.emit("worker", event);

				if (event.intercepted) return event.returnValue;
				const worker = new event.target(
					...[event.data.url, event.data.options]
				);

				const conn = new BareMuxConnection();
				(async () => {
					const port = await conn.getInnerPort();
					worker.postMessage(
						{
							__uv$type: "baremuxinit",
							port,
						},
						[port]
					);
				})();

				return worker;
			},
			true
		);
	}
	overrideAddModule() {
		this.ctx.override(this.workletProto, "addModule", (target, that, args) => {
			if (!args.length) return target.apply(that, args);
			let [url, options = {}] = args;

			const event = new HookEvent({ url, options }, target, that);
			this.emit("addModule", event);

			if (event.intercepted) return event.returnValue;
			return event.target.call(event.that, event.data.url, event.data.options);
		});
	}
	overridePostMessage() {
		this.ctx.override(this.workerProto, "postMessage", (target, that, args) => {
			if (!args.length) return target.apply(that, args);
			let [message, transfer = []] = args;

			const event = new HookEvent({ message, transfer }, target, that);
			this.emit("postMessage", event);

			if (event.intercepted) return event.returnValue;
			return event.target.call(
				event.that,
				event.data.message,
				event.data.transfer
			);
		});
	}
	overrideImportScripts() {
		this.ctx.override(this.window, "importScripts", (target, that, scripts) => {
			if (!scripts.length) return target.apply(that, scripts);

			const event = new HookEvent({ scripts }, target, that);
			this.emit("importScripts", event);

			if (event.intercepted) return event.returnValue;
			return event.target.apply(event.that, event.data.scripts);
		});
	}
}

export default Workers;