refactor: isomorphic snapshot for CLI (#3728)

1 files changed, 126 insertions, 0 deletions

diff --git a/cli/js/runtime_worker.ts b/cli/js/runtime_worker.ts
new file mode 100644
index 000000000..7f1d1b69c
--- /dev/null
+++ b/cli/js/runtime_worker.ts
@@ -0,0 +1,126 @@
+// 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 two functions that should be called by Rust:
+//  - `bootstrapWorkerRuntime` - must be called once, when Isolate is created.
+//   It sets up runtime by providing globals for `DedicatedWorkerScope`.
+//  - `runWorkerMessageLoop` - starts receiving messages from parent worker,
+//   can be called multiple times - eg. to restart worker execution after
+//   exception occurred and was handled by parent worker
+
+/* eslint-disable @typescript-eslint/no-explicit-any */
+import {
+  readOnly,
+  writable,
+  nonEnumerable,
+  windowOrWorkerGlobalScopeMethods,
+  windowOrWorkerGlobalScopeProperties,
+  eventTargetProperties
+} from "./globals.ts";
+import * as dispatch from "./dispatch.ts";
+import { sendAsync, sendSync } from "./dispatch_json.ts";
+import { log } from "./util.ts";
+import { TextDecoder, TextEncoder } from "./text_encoding.ts";
+import * as runtime from "./runtime.ts";
+
+const encoder = new TextEncoder();
+const decoder = new TextDecoder();
+
+// 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);
+  sendSync(dispatch.OP_WORKER_POST_MESSAGE, {}, dataIntArray);
+}
+
+export async function getMessage(): Promise<any> {
+  log("getMessage");
+  const res = await sendAsync(dispatch.OP_WORKER_GET_MESSAGE);
+  if (res.data != null) {
+    const dataIntArray = new Uint8Array(res.data);
+    const dataJson = decoder.decode(dataIntArray);
+    return JSON.parse(dataJson);
+  } else {
+    return null;
+  }
+}
+
+let isClosing = false;
+let hasBootstrapped = false;
+
+export function workerClose(): void {
+  isClosing = true;
+}
+
+export async function runWorkerMessageLoop(): Promise<void> {
+  while (!isClosing) {
+    const data = await getMessage();
+    if (data == null) {
+      log("runWorkerMessageLoop got null message. quitting.");
+      break;
+    }
+
+    let result: void | Promise<void>;
+    const event = { data };
+
+    try {
+      if (!globalThis["onmessage"]) {
+        break;
+      }
+      result = globalThis.onmessage!(event);
+      if (result && "then" in result) {
+        await result;
+      }
+      if (!globalThis["onmessage"]) {
+        break;
+      }
+    } catch (e) {
+      if (globalThis["onerror"]) {
+        const result = globalThis.onerror(
+          e.message,
+          e.fileName,
+          e.lineNumber,
+          e.columnNumber,
+          e
+        );
+        if (result === true) {
+          continue;
+        }
+      }
+      throw e;
+    }
+  }
+}
+
+export const workerRuntimeGlobalProperties = {
+  self: readOnly(globalThis),
+  onmessage: writable(onmessage),
+  onerror: writable(onerror),
+  workerClose: nonEnumerable(workerClose),
+  postMessage: writable(postMessage)
+};
+
+/**
+ * Main method to initialize worker runtime.
+ *
+ * It sets up global variables for DedicatedWorkerScope,
+ * and initializes ops.
+ */
+export function bootstrapWorkerRuntime(name: string): void {
+  if (hasBootstrapped) {
+    throw new Error("Worker runtime already bootstrapped");
+  }
+  log("bootstrapWorkerRuntime");
+  hasBootstrapped = true;
+  Object.defineProperties(globalThis, windowOrWorkerGlobalScopeMethods);
+  Object.defineProperties(globalThis, windowOrWorkerGlobalScopeProperties);
+  Object.defineProperties(globalThis, workerRuntimeGlobalProperties);
+  Object.defineProperties(globalThis, eventTargetProperties);
+  runtime.start(false, name);
+}