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;
   },
 });

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() {

runtime/js/99_main.js

@@ -66,7 +66,7 @@ delete Object.prototype.__proto__;
     }
 
     isClosing = true;
-    opCloseWorker();
+    core.opSync("op_worker_close");
   }
 
   // TODO(bartlomieju): remove these functions
@@ -75,68 +75,67 @@ delete Object.prototype.__proto__;
   const onerror = () => {};
 
   function postMessage(data) {
-    const dataJson = JSON.stringify(data);
-    const dataIntArray = encoder.encode(dataJson);
-    opPostMessage(dataIntArray);
+    const dataIntArray = core.serialize(data);
+    core.opSync("op_worker_post_message", null, dataIntArray);
   }
 
   let isClosing = false;
-  async function workerMessageRecvCallback(data) {
-    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,
+  async function pollForMessages() {
+    while (!isClosing) {
+      const bufferMsg = await core.opAsync("op_worker_get_message");
+      const data = core.deserialize(bufferMsg);
+
+      const msgEvent = new MessageEvent("message", {
+        cancelable: false,
+        data,
       });
 
-      if (globalThis["onerror"]) {
-        const ret = globalThis.onerror(
-          e.message,
-          e.fileName,
-          e.lineNumber,
-          e.columnNumber,
-          e,
-        );
-        handled = ret === true;
-      }
+      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;
-      }
+        globalThis.dispatchEvent(errorEvent);
+        if (errorEvent.defaultPrevented) {
+          handled = true;
+        }
 
-      if (!handled) {
-        throw e;
+        if (!handled) {
+          core.opSync(
+            "op_worker_unhandled_error",
+            e.message,
+          );
+        }
       }
     }
   }
 
-  function opPostMessage(data) {
-    core.opSync("op_worker_post_message", null, data);
-  }
-
-  function opCloseWorker() {
-    core.opSync("op_worker_close");
-  }
-
   function opMainModule() {
     return core.opSync("op_main_module");
   }
@@ -371,7 +370,6 @@ delete Object.prototype.__proto__;
     // TODO(bartlomieju): should be readonly?
     close: util.nonEnumerable(workerClose),
     postMessage: util.writable(postMessage),
-    workerMessageRecvCallback: util.nonEnumerable(workerMessageRecvCallback),
   };
 
   let hasBootstrapped = false;
@@ -482,6 +480,8 @@ delete Object.prototype.__proto__;
     location.setLocationHref(locationHref);
     registerErrors();
 
+    pollForMessages();
+
     const internalSymbol = Symbol("Deno.internal");
 
     const finalDenoNs = {