deno/cli/js/runtime_worker.ts

// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.

// This module is the entry point for "worker" isolate, ie. the one
// that is created using `new Worker()` JS API.
//
// It provides a single function that should be called by Rust:
//  - `bootstrapWorkerRuntime` - must be called once, when Isolate is created.
//   It sets up runtime by providing globals for `DedicatedWorkerScope`.

/* eslint-disable @typescript-eslint/no-explicit-any */
import {
  readOnly,
  writable,
  nonEnumerable,
  windowOrWorkerGlobalScopeMethods,
  windowOrWorkerGlobalScopeProperties,
  eventTargetProperties,
  setEventTargetData,
} from "./globals.ts";
import { unstableMethods, unstableProperties } from "./globals_unstable.ts";
import * as denoNs from "./deno.ts";
import * as denoUnstableNs from "./deno_unstable.ts";
import * as webWorkerOps from "./ops/web_worker.ts";
import { log, assert, immutableDefine } from "./util.ts";
import { ErrorEventImpl as ErrorEvent } from "./web/error_event.ts";
import { MessageEvent } from "./web/workers.ts";
import { TextEncoder } from "./web/text_encoding.ts";
import * as runtime from "./runtime.ts";
import { internalObject, internalSymbol } from "./internals.ts";
import { setSignals } from "./signals.ts";

// FIXME(bartlomieju): duplicated in `runtime_main.ts`
// TODO: factor out `Deno` global assignment to separate function
// Add internal object to Deno object.
// This is not exposed as part of the Deno types.
// eslint-disable-next-line @typescript-eslint/no-explicit-any
(denoNs as any)[internalSymbol] = internalObject;

const encoder = new TextEncoder();

// TODO(bartlomieju): remove these funtions
// Stuff for workers
export const onmessage: (e: { data: any }) => void = (): void => {};
export const onerror: (e: { data: any }) => void = (): void => {};

export function postMessage(data: any): void {
  const dataJson = JSON.stringify(data);
  const dataIntArray = encoder.encode(dataJson);
  webWorkerOps.postMessage(dataIntArray);
}

let isClosing = false;
let hasBootstrapped = false;

export function close(): void {
  if (isClosing) {
    return;
  }

  isClosing = true;
  webWorkerOps.close();
}

export async function workerMessageRecvCallback(data: string): Promise<void> {
  const msgEvent = new MessageEvent("message", {
    cancelable: false,
    data,
  });

  try {
    if (globalThis["onmessage"]) {
      const result = globalThis.onmessage!(msgEvent);
      if (result && "then" in result) {
        await result;
      }
    }
    globalThis.dispatchEvent(msgEvent);
  } catch (e) {
    let handled = false;

    const errorEvent = new ErrorEvent("error", {
      cancelable: true,
      message: e.message,
      lineno: e.lineNumber ? e.lineNumber + 1 : undefined,
      colno: e.columnNumber ? e.columnNumber + 1 : undefined,
      filename: e.fileName,
      error: null,
    });

    if (globalThis["onerror"]) {
      const ret = globalThis.onerror(
        e.message,
        e.fileName,
        e.lineNumber,
        e.columnNumber,
        e
      );
      handled = ret === true;
    }

    globalThis.dispatchEvent(errorEvent);
    if (errorEvent.defaultPrevented) {
      handled = true;
    }

    if (!handled) {
      throw e;
    }
  }
}

export const workerRuntimeGlobalProperties = {
  self: readOnly(globalThis),
  onmessage: writable(onmessage),
  onerror: writable(onerror),
  // TODO: should be readonly?
  close: nonEnumerable(close),
  postMessage: writable(postMessage),
  workerMessageRecvCallback: nonEnumerable(workerMessageRecvCallback),
};

export function bootstrapWorkerRuntime(
  name: string,
  useDenoNamespace: boolean,
  internalName?: string
): void {
  if (hasBootstrapped) {
    throw new Error("Worker runtime already bootstrapped");
  }
  // Remove bootstrapping methods from global scope
  // eslint-disable-next-line @typescript-eslint/no-explicit-any
  (globalThis as any).bootstrap = undefined;
  log("bootstrapWorkerRuntime");
  hasBootstrapped = true;
  Object.defineProperties(globalThis, windowOrWorkerGlobalScopeMethods);
  Object.defineProperties(globalThis, windowOrWorkerGlobalScopeProperties);
  Object.defineProperties(globalThis, workerRuntimeGlobalProperties);
  Object.defineProperties(globalThis, eventTargetProperties);
  Object.defineProperties(globalThis, { name: readOnly(name) });
  setEventTargetData(globalThis);
  const { unstableFlag, pid, noColor, args } = runtime.start(
    internalName ?? name
  );

  if (unstableFlag) {
    Object.defineProperties(globalThis, unstableMethods);
    Object.defineProperties(globalThis, unstableProperties);
  }

  if (useDenoNamespace) {
    if (unstableFlag) {
      Object.assign(denoNs, denoUnstableNs);
    }
    Object.defineProperties(denoNs, {
      pid: readOnly(pid),
      noColor: readOnly(noColor),
      args: readOnly(Object.freeze(args)),
    });
    // Setup `Deno` global - we're actually overriding already
    // existing global `Deno` with `Deno` namespace from "./deno.ts".
    immutableDefine(globalThis, "Deno", denoNs);
    Object.freeze(globalThis.Deno);
    Object.freeze(globalThis.Deno.core);
    Object.freeze(globalThis.Deno.core.sharedQueue);
    setSignals();
  } else {
    delete globalThis.Deno;
    assert(globalThis.Deno === undefined);
  }
}