feat(runtime/worker): Structured cloning worker message passing.

cli/bench/main.rs

@@ -75,7 +75,7 @@ const EXEC_TIME_BENCHMARKS: &[(&str, &[&str], Option<i32>)] = &[
     &[
       "run",
       "--allow-read",
-      "cli/tests/workers_large_message_bench.ts",
+      "cli/tests/workers/bench_large_message.ts",
     ],
     None,
   ),

cli/tests/workers_large_message_bench.ts → cli/tests/workers/bench_large_message.ts

@@ -1,14 +1,10 @@
 // Copyright 2020 the Deno authors. All rights reserved. MIT license.
 
-// deno-lint-ignore-file
-
-import { deferred } from "../../test_util/std/async/deferred.ts";
-
-function oneWorker(i: any): Promise<void> {
+function oneWorker(i: number) {
   return new Promise<void>((resolve) => {
     let countDown = 10;
     const worker = new Worker(
-      new URL("workers/large_message_worker.js", import.meta.url).href,
+      new URL("worker_large_message.js", import.meta.url).href,
       { type: "module" },
     );
     worker.onmessage = (e): void => {
@@ -23,8 +19,8 @@ function oneWorker(i: any): Promise<void> {
   });
 }
 
-function bench(): Promise<any> {
-  let promises = [];
+function bench() {
+  const promises = [];
   for (let i = 0; i < 50; i++) {
     promises.push(oneWorker(i));
   }

cli/tests/workers/racy_worker.js

@@ -1,21 +1,25 @@
 // See issue for details
 // https://github.com/denoland/deno/issues/4080
 //
-// After first call to `postMessage() this worker schedules
-// [close(), postMessage()] ops on the same turn of microtask queue
-// (because message is rather big).
-// Only single `postMessage()` call should make it
-// to host, ie. after calling `close()` no more code should be run.
+// After first received message, this worker schedules
+// [assert(), close(), assert()] ops on the same turn of microtask queue
+// All tasks after close should not make it
 
-setTimeout(() => {
-  close();
-}, 50);
-
-while (true) {
-  await new Promise((done) => {
+onmessage = async function () {
+  let stage = 0;
+  await new Promise((_) => {
+    setTimeout(() => {
+      if (stage !== 0) throw "Unexpected stage";
+      stage = 1;
+    }, 50);
+    setTimeout(() => {
+      if (stage !== 1) throw "Unexpected stage";
+      stage = 2;
+      postMessage("DONE");
+      close();
+    }, 50);
     setTimeout(() => {
-      postMessage({ buf: new Array(999999) });
-      done();
-    });
+      throw "This should not be run";
+    }, 50);
   });
-}
+};

cli/tests/workers/test.ts

@@ -198,15 +198,12 @@ Deno.test({
     );
 
     racyWorker.onmessage = (e): void => {
-      assertEquals(e.data.buf.length, 999999);
-      racyWorker.onmessage = (_e): void => {
-        throw new Error("unreachable");
-      };
       setTimeout(() => {
         promise.resolve();
       }, 100);
     };
 
+    racyWorker.postMessage("START");
     await promise;
   },
 });
@@ -726,3 +723,38 @@ Deno.test({
     worker.terminate();
   },
 });
+
+Deno.test({
+  name: "structured cloning postMessage",
+  fn: async function (): Promise<void> {
+    const result = deferred();
+    const worker = new Worker(
+      new URL("worker_structured_cloning.ts", import.meta.url).href,
+      { type: "module" },
+    );
+
+    worker.onmessage = (e): void => {
+      // self field should reference itself (circular ref)
+      const value = e.data.self.self.self;
+
+      // fields a and b refer to the same array
+      assertEquals(value.a, ["a", true, 432]);
+      assertEquals(value.a, ["a", true, 432]);
+      value.b[0] = "b";
+      value.a[2] += 5;
+      assertEquals(value.a, ["b", true, 437]);
+      assertEquals(value.b, ["b", true, 437]);
+
+      const len = value.c.size;
+      value.c.add(1); // This value is already in the set.
+      value.c.add(2);
+      assertEquals(len + 1, value.c.size);
+
+      result.resolve();
+    };
+
+    worker.postMessage("START");
+    await result;
+    worker.terminate();
+  },
+});

cli/tests/workers/worker_structured_cloning.ts

@@ -0,0 +1,15 @@
+// More info on structured cloning can be found here:
+// https://developer.mozilla.org/en-US/docs/Web/API/Web_Workers_API/Structured_clone_algorithm
+
+self.onmessage = () => {
+  const arr = ["a", true, 432];
+  const set = new Set([1, 3, 5, 7, 9]);
+  const selfReference = {
+    a: arr,
+    b: arr,
+    c: set,
+  };
+  // deno-lint-ignore no-explicit-any
+  (selfReference as any).self = selfReference;
+  self.postMessage(selfReference);
+};

core/bindings.rs

@@ -553,7 +553,7 @@ fn deserialize(
   match value {
     Some(deserialized) => rv.set(deserialized),
     None => {
-      let msg = v8::String::new(scope, "string too long").unwrap();
+      let msg = v8::String::new(scope, "could not deserialize value").unwrap();
       let exception = v8::Exception::range_error(scope, msg);
       scope.throw_exception(exception);
     }

runtime/js/11_workers.js

@@ -39,26 +39,8 @@
     return core.opAsync("op_host_get_message", id);
   }
 
-  const encoder = new TextEncoder();
   const decoder = new TextDecoder();
 
-  function encodeMessage(data) {
-    const dataJson = JSON.stringify(data);
-    return encoder.encode(dataJson);
-  }
-
-  function decodeMessage(dataIntArray) {
-    // Temporary solution until structured clone arrives in v8.
-    // Current clone is made by parsing json to byte array and from byte array back to json.
-    // In that case "undefined" transforms to empty byte array, but empty byte array does not transform back to undefined.
-    // Thats why this special is statement is needed.
-    if (dataIntArray.length == 0) {
-      return undefined;
-    }
-    const dataJson = decoder.decode(dataIntArray);
-    return JSON.parse(dataJson);
-  }
-
   /**
    * @param {string} permission
    * @return {boolean}
@@ -211,18 +193,7 @@
       this.#poll();
     }
 
-    #handleMessage = (msgData) => {
-      let data;
-      try {
-        data = decodeMessage(new Uint8Array(msgData));
-      } catch (e) {
-        const msgErrorEvent = new MessageEvent("messageerror", {
-          cancelable: false,
-          data,
-        });
-        return;
-      }
-
+    #handleMessage = (data) => {
       const msgEvent = new MessageEvent("message", {
         cancelable: false,
         data,
@@ -253,56 +224,44 @@
 
     #poll = async () => {
       while (!this.#terminated) {
-        const event = await hostGetMessage(this.#id);
+        const [type, data] = await hostGetMessage(this.#id);
 
         // If terminate was called then we ignore all messages
         if (this.#terminated) {
           return;
         }
 
-        const type = event.type;
-
-        if (type === "terminalError") {
-          this.#terminated = true;
-          if (!this.#handleError(event.error)) {
-            if (globalThis instanceof Window) {
-              throw new Error("Unhandled error event reached main worker.");
-            } else {
-              core.opSync(
-                "op_host_unhandled_error",
-                event.error.message,
-              );
-            }
+        switch (type) {
+          case 0: { // Message
+            const msg = core.deserialize(data);
+            this.#handleMessage(msg);
+            break;
           }
-          continue;
-        }
-
-        if (type === "msg") {
-          this.#handleMessage(event.data);
-          continue;
-        }
-
-        if (type === "error") {
-          if (!this.#handleError(event.error)) {
-            if (globalThis instanceof Window) {
-              throw new Error("Unhandled error event reached main worker.");
-            } else {
-              core.opSync(
-                "op_host_unhandled_error",
-                event.error.message,
-              );
+          case 1: { // TerminalError
+            this.#terminated = true;
+          } /* falls through */
+          case 2: { // Error
+            if (!this.#handleError(data)) {
+              if (globalThis instanceof Window) {
+                throw new Error("Unhandled error event reached main worker.");
+              } else {
+                core.opSync(
+                  "op_worker_unhandled_error",
+                  data.message,
+                );
+              }
             }
+            break;
+          }
+          case 3: { // Close
+            log(`Host got "close" message from worker: ${this.#name}`);
+            this.#terminated = true;
+            return;
+          }
+          default: {
+            throw new Error(`Unknown worker event: "${type}"`);
           }
-          continue;
-        }
-
-        if (type === "close") {
-          log(`Host got "close" message from worker: ${this.#name}`);
-          this.#terminated = true;
-          return;
         }
-
-        throw new Error(`Unknown worker event: "${type}"`);
       }
     };
 
@@ -317,7 +276,8 @@
         return;
       }
 
-      hostPostMessage(this.#id, encodeMessage(message));
+      const bufferMsg = core.serialize(message);
+      hostPostMessage(this.#id, bufferMsg);
     }
 
     terminate() {