src: implement structuredClone in native

Simplify the implementation by implementing it directly in C++.
This improves performance and also makes structuredClone supported
in custom snapshots.

PR-URL: https://github.com/nodejs/node/pull/50330
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Chengzhong Wu <legendecas@gmail.com>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
Reviewed-By: Daeyeon Jeong <daeyeon.dev@gmail.com>

benchmark/misc/structured-clone.js

@@ -0,0 +1,46 @@
+'use strict';
+
+const common = require('../common.js');
+const assert = require('assert');
+
+const bench = common.createBenchmark(main, {
+  type: ['string', 'object', 'arraybuffer'],
+  n: [1e4],
+});
+
+function main({ n, type }) {
+  const data = [];
+
+  switch (type) {
+    case 'string':
+      for (let i = 0; i < n; ++i) {
+        data.push(new Date().toISOString());
+      }
+      break;
+    case 'object':
+      for (let i = 0; i < n; ++i) {
+        data.push({ ...process.config });
+      }
+      break;
+    case 'arraybuffer':
+      for (let i = 0; i < n; ++i) {
+        data.push(new ArrayBuffer(10));
+      }
+      break;
+    default:
+      throw new Error('Unsupported payload type');
+  }
+
+  const run = type === 'arraybuffer' ? (i) => {
+    data[i] = structuredClone(data[i], { transfer: [ data[i] ] });
+  } : (i) => {
+    data[i] = structuredClone(data[i]);
+  };
+
+  bench.start();
+  for (let i = 0; i < n; ++i) {
+    run(i);
+  }
+  bench.end(n);
+  assert.strictEqual(data.length, n);
+}

lib/.eslintrc.yaml

@@ -172,7 +172,7 @@ rules:
     - name: setTimeout
       message: Use `const { setTimeout } = require('timers');` instead of the global.
     - name: structuredClone
-      message: Use `const { structuredClone } = require('internal/structured_clone');` instead of the global.
+      message: Use `const { structuredClone } = internalBinding('messaging');` instead of the global.
     - name: SubtleCrypto
       message: Use `const { SubtleCrypto } = require('internal/crypto/webcrypto');` instead of the global.
   no-restricted-modules:

lib/internal/bootstrap/web/exposed-window-or-worker.js

@@ -31,11 +31,8 @@ const {
 } = require('internal/process/task_queues');
 defineOperation(globalThis, 'queueMicrotask', queueMicrotask);
 
-defineLazyProperties(
+const { structuredClone } = internalBinding('messaging');
-  globalThis,
+defineOperation(globalThis, 'structuredClone', structuredClone);
-  'internal/structured_clone',
-  ['structuredClone'],
-);
 defineLazyProperties(globalThis, 'buffer', ['atob', 'btoa']);
 
 // https://html.spec.whatwg.org/multipage/web-messaging.html#broadcasting-to-other-browsing-contexts

lib/internal/perf/usertiming.js

@@ -31,7 +31,7 @@ const {
   },
 } = require('internal/errors');
 
-const { structuredClone } = require('internal/structured_clone');
+const { structuredClone } = internalBinding('messaging');
 const {
   lazyDOMException,
   kEnumerableProperty,

lib/internal/structured_clone.js

@@ -1,29 +0,0 @@
-'use strict';
-
-const {
-  codes: { ERR_MISSING_ARGS },
-} = require('internal/errors');
-
-const {
-  MessageChannel,
-  receiveMessageOnPort,
-} = require('internal/worker/io');
-
-let channel;
-function structuredClone(value, options = undefined) {
-  if (arguments.length === 0) {
-    throw new ERR_MISSING_ARGS('value');
-  }
-
-  // TODO: Improve this with a more efficient solution that avoids
-  // instantiating a MessageChannel
-  channel ??= new MessageChannel();
-  channel.port1.unref();
-  channel.port2.unref();
-  channel.port1.postMessage(value, options?.transfer);
-  return receiveMessageOnPort(channel.port2).message;
-}
-
-module.exports = {
-  structuredClone,
-};

lib/internal/webstreams/readablestream.js

@@ -85,9 +85,7 @@ const {
   kControllerErrorFunction,
 } = require('internal/streams/utils');
 
-const {
+const { structuredClone } = internalBinding('messaging');
-  structuredClone,
-} = require('internal/structured_clone');
 
 const {
   ArrayBufferViewGetBuffer,

src/node_messaging.cc

@@ -1008,6 +1008,47 @@ static Maybe<bool> ReadIterable(Environment* env,
   return Just(true);
 }
 
+bool GetTransferList(Environment* env,
+                     Local<Context> context,
+                     Local<Value> transfer_list_v,
+                     TransferList* transfer_list_out) {
+  if (transfer_list_v->IsNullOrUndefined()) {
+    // Browsers ignore null or undefined, and otherwise accept an array or an
+    // options object.
+    return true;
+  }
+
+  if (!transfer_list_v->IsObject()) {
+    THROW_ERR_INVALID_ARG_TYPE(
+        env, "Optional transferList argument must be an iterable");
+    return false;
+  }
+
+  bool was_iterable;
+  if (!ReadIterable(env, context, *transfer_list_out, transfer_list_v)
+           .To(&was_iterable))
+    return false;
+  if (!was_iterable) {
+    Local<Value> transfer_option;
+    if (!transfer_list_v.As<Object>()
+             ->Get(context, env->transfer_string())
+             .ToLocal(&transfer_option))
+      return false;
+    if (!transfer_option->IsUndefined()) {
+      if (!ReadIterable(env, context, *transfer_list_out, transfer_option)
+               .To(&was_iterable))
+        return false;
+      if (!was_iterable) {
+        THROW_ERR_INVALID_ARG_TYPE(
+            env, "Optional options.transfer argument must be an iterable");
+        return false;
+      }
+    }
+  }
+
+  return true;
+}
+
 void MessagePort::PostMessage(const FunctionCallbackInfo<Value>& args) {
   Environment* env = Environment::GetCurrent(args);
   Local<Object> obj = args.This();
@@ -1018,33 +1059,10 @@ void MessagePort::PostMessage(const FunctionCallbackInfo<Value>& args) {
                                        "MessagePort.postMessage");
   }
 
-  if (!args[1]->IsNullOrUndefined() && !args[1]->IsObject()) {
-    // Browsers ignore null or undefined, and otherwise accept an array or an
-    // options object.
-    return THROW_ERR_INVALID_ARG_TYPE(env,
-        "Optional transferList argument must be an iterable");
-  }
-
   TransferList transfer_list;
-  if (args[1]->IsObject()) {
+  if (!GetTransferList(env, context, args[1], &transfer_list)) {
-    bool was_iterable;
-    if (!ReadIterable(env, context, transfer_list, args[1]).To(&was_iterable))
     return;
-    if (!was_iterable) {
-      Local<Value> transfer_option;
-      if (!args[1].As<Object>()->Get(context, env->transfer_string())
-          .ToLocal(&transfer_option)) return;
-      if (!transfer_option->IsUndefined()) {
-        if (!ReadIterable(env, context, transfer_list, transfer_option)
-            .To(&was_iterable)) return;
-        if (!was_iterable) {
-          return THROW_ERR_INVALID_ARG_TYPE(env,
-              "Optional options.transfer argument must be an iterable");
   }
-      }
-    }
-  }
-
   MessagePort* port = Unwrap<MessagePort>(args.This());
   // Even if the backing MessagePort object has already been deleted, we still
   // want to serialize the message to ensure spec-compliant behavior w.r.t.
@@ -1535,6 +1553,48 @@ static void SetDeserializerCreateObjectFunction(
   env->set_messaging_deserialize_create_object(args[0].As<Function>());
 }
 
+static void StructuredClone(const FunctionCallbackInfo<Value>& args) {
+  Isolate* isolate = args.GetIsolate();
+  Local<Context> context = isolate->GetCurrentContext();
+  Realm* realm = Realm::GetCurrent(context);
+  Environment* env = realm->env();
+
+  if (args.Length() == 0) {
+    return THROW_ERR_MISSING_ARGS(env, "The value argument must be specified");
+  }
+
+  Local<Value> value = args[0];
+
+  TransferList transfer_list;
+  if (!args[1]->IsNullOrUndefined()) {
+    if (!args[1]->IsObject()) {
+      return THROW_ERR_INVALID_ARG_TYPE(
+          env, "The options argument must be either an object or undefined");
+    }
+    Local<Object> options = args[1].As<Object>();
+    Local<Value> transfer_list_v;
+    if (!options->Get(context, env->transfer_string())
+             .ToLocal(&transfer_list_v)) {
+      return;
+    }
+
+    // TODO(joyeecheung): implement this in JS land to avoid the C++ -> JS
+    // cost to convert a sequence into an array.
+    if (!GetTransferList(env, context, transfer_list_v, &transfer_list)) {
+      return;
+    }
+  }
+
+  std::shared_ptr<Message> msg = std::make_shared<Message>();
+  Local<Value> result;
+  if (msg->Serialize(env, context, value, transfer_list, Local<Object>())
+          .IsNothing() ||
+      !msg->Deserialize(env, context, nullptr).ToLocal(&result)) {
+    return;
+  }
+  args.GetReturnValue().Set(result);
+}
+
 static void MessageChannel(const FunctionCallbackInfo<Value>& args) {
   Environment* env = Environment::GetCurrent(args);
   if (!args.IsConstructCall()) {
@@ -1615,6 +1675,7 @@ static void InitMessaging(Local<Object> target,
             "setDeserializerCreateObjectFunction",
             SetDeserializerCreateObjectFunction);
   SetMethod(context, target, "broadcastChannel", BroadcastChannel);
+  SetMethod(context, target, "structuredClone", StructuredClone);
 
   {
     Local<Function> domexception = GetDOMException(context).ToLocalChecked();
@@ -1638,6 +1699,7 @@ static void RegisterExternalReferences(ExternalReferenceRegistry* registry) {
   registry->Register(MessagePort::ReceiveMessage);
   registry->Register(MessagePort::MoveToContext);
   registry->Register(SetDeserializerCreateObjectFunction);
+  registry->Register(StructuredClone);
 }
 
 }  // anonymous namespace

test/parallel/test-structuredClone-global.js

@@ -1,23 +1,17 @@
-// Flags: --expose-internals
 'use strict';
-/* eslint-disable no-global-assign */
 
 require('../common');
+const assert = require('assert');
 
-const {
+assert.throws(() => structuredClone(), { code: 'ERR_MISSING_ARGS' });
-  structuredClone: _structuredClone,
+assert.throws(() => structuredClone(undefined, ''), { code: 'ERR_INVALID_ARG_TYPE' });
-} = require('internal/structured_clone');
+assert.throws(() => structuredClone(undefined, 1), { code: 'ERR_INVALID_ARG_TYPE' });
+assert.throws(() => structuredClone(undefined, { transfer: 1 }), { code: 'ERR_INVALID_ARG_TYPE' });
+assert.throws(() => structuredClone(undefined, { transfer: '' }), { code: 'ERR_INVALID_ARG_TYPE' });
 
-const {
+// Options can be null or undefined.
-  strictEqual,
+assert.strictEqual(structuredClone(undefined), undefined);
-  throws,
+assert.strictEqual(structuredClone(undefined, null), undefined);
-} = require('assert');
+// Transfer can be null or undefined.
-
+assert.strictEqual(structuredClone(undefined, { transfer: null }), undefined);
-strictEqual(globalThis.structuredClone, _structuredClone);
+assert.strictEqual(structuredClone(undefined, { }), undefined);
-structuredClone = undefined;
-strictEqual(globalThis.structuredClone, undefined);
-
-// Restore the value for the known globals check.
-structuredClone = _structuredClone;
-
-throws(() => _structuredClone(), /ERR_MISSING_ARGS/);