Merge pull request 'Implement `self.structuredClone()`' (#2206) from FranklinDM/UXP-contrib:work_js-structuredclone into master

Reviewed-on: https://repo.palemoon.org/MoonchildProductions/UXP/pulls/2206

26 files changed, 344 insertions, 147 deletions

diff --git a/dom/base/nsContentUtils.cpp b/dom/base/nsContentUtils.cpp
index 990e1bc589..86e52984af 100644
--- a/dom/base/nsContentUtils.cpp
+++ b/dom/base/nsContentUtils.cpp
@@ -47,6 +47,7 @@
 #include "mozilla/dom/HTMLTemplateElement.h"
 #include "mozilla/dom/ipc/BlobChild.h"
 #include "mozilla/dom/ipc/BlobParent.h"
+#include "mozilla/dom/MessagePort.h"
 #include "mozilla/dom/Promise.h"
 #include "mozilla/dom/ScriptSettings.h"
 #include "mozilla/dom/TabParent.h"
@@ -9991,3 +9992,71 @@ nsContentUtils::GetClosestNonNativeAnonymousAncestor(Element* aElement)
   }
   return e;
 }
+
+/* static */ nsresult
+nsContentUtils::CreateJSValueFromSequenceOfObject(JSContext* aCx,
+                                                  const Sequence<JSObject*>& aTransfer,
+                                                  JS::MutableHandle<JS::Value> aValue)
+{
+  if (aTransfer.IsEmpty()) {
+    return NS_OK;
+  }
+
+  JS::Rooted<JSObject*> array(aCx, JS_NewArrayObject(aCx, aTransfer.Length()));
+  if (!array) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+
+  for (uint32_t i = 0; i < aTransfer.Length(); ++i) {
+    JS::Rooted<JSObject*> object(aCx, aTransfer[i]);
+    if (!object) {
+      continue;
+    }
+
+    if (NS_WARN_IF(!JS_DefineElement(aCx, array, i, object,
+                                     JSPROP_ENUMERATE))) {
+      return NS_ERROR_OUT_OF_MEMORY;
+    }
+  }
+
+  aValue.setObject(*array);
+  return NS_OK;
+}
+
+/* static */
+void nsContentUtils::StructuredClone(JSContext* aCx,
+                                     nsIGlobalObject* aGlobal,
+                                     JS::Handle<JS::Value> aValue,
+                                     const StructuredSerializeOptions& aOptions,
+                                     JS::MutableHandle<JS::Value> aRv,
+                                     ErrorResult& aError) {
+  JS::Rooted<JS::Value> transferArray(aCx, JS::UndefinedValue());
+  aError = nsContentUtils::CreateJSValueFromSequenceOfObject(
+      aCx, aOptions.mTransfer, &transferArray);
+  if (NS_WARN_IF(aError.Failed())) {
+    return;
+  }
+
+  JS::CloneDataPolicy clonePolicy;
+  // FIXME: Uncomment once bug 1609990 and bug 1611855 lands.
+  //clonePolicy.allowIntraClusterClonableSharedObjects();
+  //clonePolicy.allowSharedMemoryObjects();
+
+  StructuredCloneHolder holder(StructuredCloneHolder::CloningSupported,
+                               StructuredCloneHolder::TransferringSupported,
+                               JS::StructuredCloneScope::SameProcessDifferentThread);
+  holder.Write(aCx, aValue, transferArray, clonePolicy, aError);
+  if (NS_WARN_IF(aError.Failed())) {
+    return;
+  }
+
+  // TODO: Pass clonePolicy.
+  //holder.Read(this, aCx, aRv, clonePolicy, aError);
+  holder.Read(aGlobal, aCx, aRv, aError);
+  if (NS_WARN_IF(aError.Failed())) {
+    return;
+  }
+
+  nsTArray<RefPtr<MessagePort>> ports = holder.TakeTransferredPorts();
+  Unused << ports;
+}
diff --git a/dom/base/nsContentUtils.h b/dom/base/nsContentUtils.h
index a0c602f61a..58f9f56546 100644
--- a/dom/base/nsContentUtils.h
+++ b/dom/base/nsContentUtils.h
@@ -132,6 +132,7 @@ class nsIContentParent;
 class TabChild;
 class Selection;
 class TabParent;
+struct StructuredSerializeOptions;
 } // namespace dom
 
 namespace ipc {
@@ -2812,6 +2813,23 @@ public:
   static bool
   IsCustomElementsEnabled() { return sIsCustomElementsEnabled; }
 
+  static nsresult
+  CreateJSValueFromSequenceOfObject(JSContext* aCx,
+                                    const mozilla::dom::Sequence<JSObject*>& aTransfer,
+                                    JS::MutableHandle<JS::Value> aValue);
+
+  /**
+   * This implements the structured cloning algorithm as described by
+   * https://html.spec.whatwg.org/#structured-cloning.
+   */
+  static void
+  StructuredClone(JSContext* aCx,
+                  nsIGlobalObject* aGlobal,
+                  JS::Handle<JS::Value> aValue,
+                  const mozilla::dom::StructuredSerializeOptions& aOptions,
+                  JS::MutableHandle<JS::Value> aRv,
+                  mozilla::ErrorResult& aError);
+
 private:
   static bool InitializeEventTable();
 
diff --git a/dom/base/nsGlobalWindow.cpp b/dom/base/nsGlobalWindow.cpp
index 01023f3a2d..a816efc7cd 100644
--- a/dom/base/nsGlobalWindow.cpp
+++ b/dom/base/nsGlobalWindow.cpp
@@ -8891,30 +8891,33 @@ nsGlobalWindow::PostMessageMoz(JSContext* aCx, JS::Handle<JS::Value> aMessage,
 }
 
 void
-nsGlobalWindow::PostMessageMoz(JSContext* aCx, JS::Handle<JS::Value> aMessage,
+nsGlobalWindow::PostMessageMoz(JSContext* aCx,
+                               JS::Handle<JS::Value> aMessage,
                                const nsAString& aTargetOrigin,
-                               const Optional<Sequence<JS::Value>>& aTransfer,
+                               const Sequence<JSObject*>& aTransfer,
                                nsIPrincipal& aSubjectPrincipal,
-                               ErrorResult& aError)
+                               ErrorResult& aRv)
 {
   JS::Rooted<JS::Value> transferArray(aCx, JS::UndefinedValue());
-  if (aTransfer.WasPassed()) {
-    const Sequence<JS::Value >& values = aTransfer.Value();
-
-    // The input sequence only comes from the generated bindings code, which
-    // ensures it is rooted.
-    JS::HandleValueArray elements =
-      JS::HandleValueArray::fromMarkedLocation(values.Length(), values.Elements());
-
-    transferArray = JS::ObjectOrNullValue(JS_NewArrayObject(aCx, elements));
-    if (transferArray.isNull()) {
-      aError.Throw(NS_ERROR_OUT_OF_MEMORY);
-      return;
-    }
+  aRv = nsContentUtils::CreateJSValueFromSequenceOfObject(aCx, aTransfer,
+                                                          &transferArray);
+  if (NS_WARN_IF(aRv.Failed())) {
+    return;
   }
 
   PostMessageMoz(aCx, aMessage, aTargetOrigin, transferArray,
-                 aSubjectPrincipal, aError);
+                 aSubjectPrincipal, aRv);
+}
+
+void
+nsGlobalWindow::PostMessageMoz(JSContext* aCx,
+                               JS::Handle<JS::Value> aMessage,
+                               const WindowPostMessageOptions& aOptions,
+                               nsIPrincipal& aSubjectPrincipal,
+                               ErrorResult& aRv)
+{
+  PostMessageMoz(aCx, aMessage, aOptions.mTargetOrigin, aOptions.mTransfer,
+                 aSubjectPrincipal, aRv);
 }
 
 class nsCloseEvent : public Runnable {
@@ -14638,6 +14641,17 @@ nsGlobalWindow::CreateImageBitmap(const ImageBitmapSource& aImage,
   }
 }
 
+// https://html.spec.whatwg.org/#structured-cloning
+void
+nsGlobalWindow::StructuredClone(JSContext* aCx,
+                                JS::Handle<JS::Value> aValue,
+                                const StructuredSerializeOptions& aOptions,
+                                JS::MutableHandle<JS::Value> aRv,
+                                ErrorResult& aError)
+{
+  nsContentUtils::StructuredClone(aCx, this, aValue, aOptions, aRv, aError);
+}
+
 // Helper called by methods that move/resize the window,
 // to ensure the presContext (if any) is aware of resolution
 // change that may happen in multi-monitor configuration.
diff --git a/dom/base/nsGlobalWindow.h b/dom/base/nsGlobalWindow.h
index e593890af0..63bb574dd4 100644
--- a/dom/base/nsGlobalWindow.h
+++ b/dom/base/nsGlobalWindow.h
@@ -135,6 +135,7 @@ class TabGroup;
 class Timeout;
 class U2F;
 class WakeLock;
+struct WindowPostMessageOptions;
 class Worklet;
 namespace cache {
 class CacheStorage;
@@ -934,7 +935,12 @@ public:
   void Print(mozilla::ErrorResult& aError);
   void PostMessageMoz(JSContext* aCx, JS::Handle<JS::Value> aMessage,
                       const nsAString& aTargetOrigin,
-                      const mozilla::dom::Optional<mozilla::dom::Sequence<JS::Value > >& aTransfer,
+                      const mozilla::dom::Sequence<JSObject*>& aTransfer,
+                      nsIPrincipal& aSubjectPrincipal,
+                      mozilla::ErrorResult& aRv);
+  void PostMessageMoz(JSContext* aCx,
+                      JS::Handle<JS::Value> aMessage,
+                      const mozilla::dom::WindowPostMessageOptions& aOptions,
                       nsIPrincipal& aSubjectPrincipal,
                       mozilla::ErrorResult& aError);
   int32_t SetTimeout(JSContext* aCx, mozilla::dom::Function& aFunction,
@@ -1178,6 +1184,10 @@ public:
                     const mozilla::dom::Sequence<mozilla::dom::ChannelPixelLayout>& aLayout,
                     mozilla::ErrorResult& aRv);
 
+  void StructuredClone(JSContext* aCx, JS::Handle<JS::Value> aValue,
+                       const mozilla::dom::StructuredSerializeOptions& aOptions,
+                       JS::MutableHandle<JS::Value> aRv,
+                       mozilla::ErrorResult& aError);
 
   // ChromeWindow bits.  Do NOT call these unless your window is in
   // fact an nsGlobalChromeWindow.
diff --git a/dom/messagechannel/MessagePort.cpp b/dom/messagechannel/MessagePort.cpp
index 6f7a1abc19..5fbd1e9bb9 100644
--- a/dom/messagechannel/MessagePort.cpp
+++ b/dom/messagechannel/MessagePort.cpp
@@ -394,52 +394,39 @@ MessagePort::WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto)
 }
 
 void
-MessagePort::PostMessage(JSContext* aCx, JS::Handle<JS::Value> aMessage,
-                         const Optional<Sequence<JS::Value>>& aTransferable,
+MessagePort::PostMessage(JSContext* aCx,
+                         JS::Handle<JS::Value> aMessage,
+                         const Sequence<JSObject*>& aTransferable,
                          ErrorResult& aRv)
 {
   // We *must* clone the data here, or the JS::Value could be modified
   // by script
 
-  JS::Rooted<JS::Value> transferable(aCx, JS::UndefinedValue());
-  if (aTransferable.WasPassed()) {
-    const Sequence<JS::Value>& realTransferable = aTransferable.Value();
-
-    // Here we want to check if the transerable object list contains
-    // this port. No other checks are done.
-    for (const JS::Value& value : realTransferable) {
-      if (!value.isObject()) {
-        continue;
-      }
-
-      JS::Rooted<JSObject*> object(aCx, &value.toObject());
-
-      MessagePort* port = nullptr;
-      nsresult rv = UNWRAP_OBJECT(MessagePort, &object, port);
-      if (NS_FAILED(rv)) {
-        continue;
-      }
-
-      if (port == this) {
-        aRv.Throw(NS_ERROR_DOM_DATA_CLONE_ERR);
-        return;
-      }
+  // Here we want to check if the transferable object list contains
+  // this port.
+  for (uint32_t i = 0; i < aTransferable.Length(); ++i) {
+    JSObject* rawObject = aTransferable[i];
+    if (!rawObject) {
+      continue;
     }
 
-    // The input sequence only comes from the generated bindings code, which
-    // ensures it is rooted.
-    JS::HandleValueArray elements =
-      JS::HandleValueArray::fromMarkedLocation(realTransferable.Length(),
-                                               realTransferable.Elements());
+    JS::Rooted<JSObject*> object(aCx, rawObject);
 
-    JSObject* array =
-      JS_NewArrayObject(aCx, elements);
-    if (!array) {
-      aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
+    MessagePort* port = nullptr;
+    nsresult rv = UNWRAP_OBJECT(MessagePort, &object, port);
+    if (NS_SUCCEEDED(rv) && port == this) {
+      aRv.Throw(NS_ERROR_DOM_DATA_CLONE_ERR);
       return;
     }
+  }
 
-    transferable.setObject(*array);
+  JS::Rooted<JS::Value> transferable(aCx, JS::UndefinedValue());
+
+  aRv = nsContentUtils::CreateJSValueFromSequenceOfObject(aCx,
+                                                          aTransferable,
+                                                          &transferable);
+  if (NS_WARN_IF(aRv.Failed())) {
+    return;
   }
 
   RefPtr<SharedMessagePortMessage> data = new SharedMessagePortMessage();
@@ -509,6 +496,14 @@ MessagePort::PostMessage(JSContext* aCx, JS::Handle<JS::Value> aMessage,
 }
 
 void
+MessagePort::PostMessage(JSContext* aCx, JS::Handle<JS::Value> aMessage,
+                         const StructuredSerializeOptions& aOptions,
+                         ErrorResult& aRv)
+{
+  PostMessage(aCx, aMessage, aOptions.mTransfer, aRv);
+}
+
+void
 MessagePort::Start()
 {
   if (mMessageQueueEnabled) {
diff --git a/dom/messagechannel/MessagePort.h b/dom/messagechannel/MessagePort.h
index 0ed2af11c1..b832872e1f 100644
--- a/dom/messagechannel/MessagePort.h
+++ b/dom/messagechannel/MessagePort.h
@@ -26,6 +26,7 @@ class MessagePortIdentifier;
 class MessagePortMessage;
 class PostMessageRunnable;
 class SharedMessagePortMessage;
+struct StructuredSerializeOptions;
 
 namespace workers {
 class WorkerHolder;
@@ -62,7 +63,12 @@ public:
 
   void
   PostMessage(JSContext* aCx, JS::Handle<JS::Value> aMessage,
-              const Optional<Sequence<JS::Value>>& aTransferable,
+              const Sequence<JSObject*>& aTransferable,
+              ErrorResult& aRv);
+
+  void
+  PostMessage(JSContext* aCx, JS::Handle<JS::Value> aMessage,
+              const StructuredSerializeOptions& aOptions,
               ErrorResult& aRv);
 
   void Start();
diff --git a/dom/tests/mochitest/whatwg/test_postMessage_origin.xhtml b/dom/tests/mochitest/whatwg/test_postMessage_origin.xhtml
index f6a9198968..e48bee136d 100644
--- a/dom/tests/mochitest/whatwg/test_postMessage_origin.xhtml
+++ b/dom/tests/mochitest/whatwg/test_postMessage_origin.xhtml
@@ -383,13 +383,6 @@ var tests =
 
      hasWrongReturnOriginBug: true
    },
-   // 55
-   {
-     args: ["NOT-RECEIVED", undefined],
-     source: "sameDomain",
-     name: "SyntaxError",
-     code: DOMException.SYNTAX_ERR
-   },
   ];
 
 function allTests(callback)
diff --git a/dom/webidl/Client.webidl b/dom/webidl/Client.webidl
index 3e79c6a635..c961c2b31f 100644
--- a/dom/webidl/Client.webidl
+++ b/dom/webidl/Client.webidl
@@ -15,7 +15,9 @@ interface Client {
   readonly attribute DOMString id;
 
   [Throws]
-  void postMessage(any message, optional sequence<Transferable> transfer);
+  void postMessage(any message, sequence<object> transferable);
+  [Throws]
+  void postMessage(any message, optional StructuredSerializeOptions options);
 };
 
 [Exposed=ServiceWorker]
diff --git a/dom/webidl/DedicatedWorkerGlobalScope.webidl b/dom/webidl/DedicatedWorkerGlobalScope.webidl
index 26dca58dab..80c7c8decb 100644
--- a/dom/webidl/DedicatedWorkerGlobalScope.webidl
+++ b/dom/webidl/DedicatedWorkerGlobalScope.webidl
@@ -16,7 +16,9 @@
  Exposed=DedicatedWorker]
 interface DedicatedWorkerGlobalScope : WorkerGlobalScope {
   [Throws]
-  void postMessage(any message, optional sequence<any> transfer);
+  void postMessage(any message, sequence<object> transfer);
+  [Throws]
+  void postMessage(any message, optional StructuredSerializeOptions options);
 
   attribute EventHandler onmessage;
 };
diff --git a/dom/webidl/MessagePort.webidl b/dom/webidl/MessagePort.webidl
index 59c61a7149..0b36c47d94 100644
--- a/dom/webidl/MessagePort.webidl
+++ b/dom/webidl/MessagePort.webidl
@@ -10,7 +10,9 @@
 [Exposed=(Window,Worker,System)]
 interface MessagePort : EventTarget {
   [Throws]
-  void postMessage(any message, optional sequence<Transferable> transferable);
+  void postMessage(any message, sequence<object> transferable);
+  [Throws]
+  void postMessage(any message, optional StructuredSerializeOptions options);
 
   void start();
   void close();
@@ -19,3 +21,8 @@ interface MessagePort : EventTarget {
   attribute EventHandler onmessage;
 };
 // MessagePort implements Transferable;
+
+// Used to declare which objects should be transferred.
+dictionary StructuredSerializeOptions {
+  sequence<object> transfer = [];
+};
\ No newline at end of file
diff --git a/dom/webidl/ServiceWorker.webidl b/dom/webidl/ServiceWorker.webidl
index 8c3749e940..ff80fafc21 100644
--- a/dom/webidl/ServiceWorker.webidl
+++ b/dom/webidl/ServiceWorker.webidl
@@ -19,9 +19,10 @@ interface ServiceWorker : EventTarget {
 
   attribute EventHandler onstatechange;
 
-  // FIXME(catalinb): Should inherit this from Worker.
   [Throws]
-  void postMessage(any message, optional sequence<Transferable> transferable);
+  void postMessage(any message, sequence<object> transferable);
+  [Throws]
+  void postMessage(any message, optional StructuredSerializeOptions options);
 };
 
 ServiceWorker implements AbstractWorker;
diff --git a/dom/webidl/Window.webidl b/dom/webidl/Window.webidl
index 6020f71dce..2ba9f4f124 100644
--- a/dom/webidl/Window.webidl
+++ b/dom/webidl/Window.webidl
@@ -22,7 +22,6 @@ interface IID;
 interface nsIBrowserDOMWindow;
 interface nsIMessageBroadcaster;
 interface nsIDOMCrypto;
-typedef any Transferable;
 
 // http://www.whatwg.org/specs/web-apps/current-work/
 [PrimaryGlobal, LegacyUnenumerableNamedProperties, NeedResolve]
@@ -81,7 +80,9 @@ typedef any Transferable;
   [Throws, UnsafeInPrerendering] void print();
 
   [Throws, CrossOriginCallable, NeedsSubjectPrincipal]
-  void postMessage(any message, DOMString targetOrigin, optional sequence<Transferable> transfer);
+  void postMessage(any message, DOMString targetOrigin, optional sequence<object> transfer = []);
+  [Throws, CrossOriginCallable, NeedsSubjectPrincipal]
+  void postMessage(any message, optional WindowPostMessageOptions options);
 
   // also has obsolete members
 };
@@ -487,3 +488,7 @@ callback IdleRequestCallback = void (IdleDeadline deadline);
 partial interface Window {
   [ChromeOnly] readonly attribute boolean isSecureContextIfOpenerIgnored;
 };
+
+dictionary WindowPostMessageOptions : StructuredSerializeOptions {
+  USVString targetOrigin = "/";
+};
diff --git a/dom/webidl/WindowOrWorkerGlobalScope.webidl b/dom/webidl/WindowOrWorkerGlobalScope.webidl
index 652a46ffcb..9e639db5f4 100644
--- a/dom/webidl/WindowOrWorkerGlobalScope.webidl
+++ b/dom/webidl/WindowOrWorkerGlobalScope.webidl
@@ -44,6 +44,10 @@ interface WindowOrWorkerGlobalScope {
   Promise<ImageBitmap> createImageBitmap(ImageBitmapSource aImage);
   [Throws]
   Promise<ImageBitmap> createImageBitmap(ImageBitmapSource aImage, long aSx, long aSy, long aSw, long aSh);
+
+  // structured cloning
+  [Throws]
+  any structuredClone(any value, optional StructuredSerializeOptions options);
 };
 
 // https://fetch.spec.whatwg.org/#fetch-method
diff --git a/dom/webidl/Worker.webidl b/dom/webidl/Worker.webidl
index 158a502d60..c13357cd7e 100644
--- a/dom/webidl/Worker.webidl
+++ b/dom/webidl/Worker.webidl
@@ -19,7 +19,9 @@ interface Worker : EventTarget {
   void terminate();
 
   [Throws]
-  void postMessage(any message, optional sequence<any> transfer);
+  void postMessage(any message, sequence<object> transfer);
+  [Throws]
+  void postMessage(any message, optional StructuredSerializeOptions options);
 
   attribute EventHandler onmessage;
 };
diff --git a/dom/workers/ServiceWorker.cpp b/dom/workers/ServiceWorker.cpp
index 16dd28b8ad..f2a39ea9c2 100644
--- a/dom/workers/ServiceWorker.cpp
+++ b/dom/workers/ServiceWorker.cpp
@@ -14,6 +14,7 @@
 
 #include "mozilla/Preferences.h"
 #include "mozilla/dom/Promise.h"
+#include "mozilla/dom/MessagePortBinding.h"
 #include "mozilla/dom/ServiceWorkerGlobalScopeBinding.h"
 
 #ifdef XP_WIN
@@ -77,7 +78,7 @@ ServiceWorker::GetScriptURL(nsString& aURL) const
 
 void
 ServiceWorker::PostMessage(JSContext* aCx, JS::Handle<JS::Value> aMessage,
-                           const Optional<Sequence<JS::Value>>& aTransferable,
+                           const Sequence<JSObject*>& aTransferable,
                            ErrorResult& aRv)
 {
   if (State() == ServiceWorkerState::Redundant) {
@@ -97,6 +98,15 @@ ServiceWorker::PostMessage(JSContext* aCx, JS::Handle<JS::Value> aMessage,
   aRv = workerPrivate->SendMessageEvent(aCx, aMessage, aTransferable, Move(clientInfo));
 }
 
+void
+ServiceWorker::PostMessage(JSContext* aCx,
+                           JS::Handle<JS::Value> aMessage,
+                           const StructuredSerializeOptions& aOptions,
+                           ErrorResult& aRv)
+{
+  PostMessage(aCx, aMessage, aOptions.mTransfer, aRv);
+}
+
 } // namespace workers
 } // namespace dom
 } // namespace mozilla
diff --git a/dom/workers/ServiceWorker.h b/dom/workers/ServiceWorker.h
index 3a3cce8260..eb14fc4293 100644
--- a/dom/workers/ServiceWorker.h
+++ b/dom/workers/ServiceWorker.h
@@ -15,6 +15,8 @@ class nsPIDOMWindowInner;
 namespace mozilla {
 namespace dom {
 
+struct StructuredSerializeOptions;
+
 namespace workers {
 
 class ServiceWorkerInfo;
@@ -63,7 +65,13 @@ public:
 
   void
   PostMessage(JSContext* aCx, JS::Handle<JS::Value> aMessage,
-              const Optional<Sequence<JS::Value>>& aTransferable,
+              const Sequence<JSObject*>& aTransferable,
+              ErrorResult& aRv);
+
+  void
+  PostMessage(JSContext* aCx,
+              JS::Handle<JS::Value> aMessage,
+              const StructuredSerializeOptions& aOptions,
               ErrorResult& aRv);
 
 private:
diff --git a/dom/workers/ServiceWorkerClient.cpp b/dom/workers/ServiceWorkerClient.cpp
index 1f845a947b..e8b8341e21 100644
--- a/dom/workers/ServiceWorkerClient.cpp
+++ b/dom/workers/ServiceWorkerClient.cpp
@@ -11,6 +11,7 @@
 #include "mozilla/dom/Navigator.h"
 #include "mozilla/dom/ServiceWorkerMessageEvent.h"
 #include "mozilla/dom/ServiceWorkerMessageEventBinding.h"
+#include "mozilla/dom/MessagePortBinding.h"
 #include "nsGlobalWindow.h"
 #include "nsIBrowserDOMWindow.h"
 #include "nsIDocument.h"
@@ -190,7 +191,7 @@ private:
 
 void
 ServiceWorkerClient::PostMessage(JSContext* aCx, JS::Handle<JS::Value> aMessage,
-                                 const Optional<Sequence<JS::Value>>& aTransferable,
+                                 const Sequence<JSObject*>& aTransferable,
                                  ErrorResult& aRv)
 {
   WorkerPrivate* workerPrivate = GetCurrentThreadWorkerPrivate();
@@ -198,20 +199,11 @@ ServiceWorkerClient::PostMessage(JSContext* aCx, JS::Handle<JS::Value> aMessage,
   workerPrivate->AssertIsOnWorkerThread();
 
   JS::Rooted<JS::Value> transferable(aCx, JS::UndefinedValue());
-  if (aTransferable.WasPassed()) {
-    const Sequence<JS::Value>& realTransferable = aTransferable.Value();
-
-    JS::HandleValueArray elements =
-      JS::HandleValueArray::fromMarkedLocation(realTransferable.Length(),
-                                               realTransferable.Elements());
-
-    JSObject* array = JS_NewArrayObject(aCx, elements);
-    if (!array) {
-      aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
-      return;
-    }
-
-    transferable.setObject(*array);
+  aRv = nsContentUtils::CreateJSValueFromSequenceOfObject(aCx,
+                                                          aTransferable,
+                                                          &transferable);
+  if (NS_WARN_IF(aRv.Failed())) {
+    return;
   }
 
   RefPtr<ServiceWorkerClientPostMessageRunnable> runnable =
@@ -229,3 +221,11 @@ ServiceWorkerClient::PostMessage(JSContext* aCx, JS::Handle<JS::Value> aMessage,
   }
 }
 
+void
+ServiceWorkerClient::PostMessage(JSContext* aCx,
+                                 JS::Handle<JS::Value> aMessage,
+                                 const StructuredSerializeOptions& aOptions,
+                                 ErrorResult& aRv)
+{
+  PostMessage(aCx, aMessage, aOptions.mTransfer, aRv);
+}
diff --git a/dom/workers/ServiceWorkerClient.h b/dom/workers/ServiceWorkerClient.h
index 46bcdbc4c4..7f89ee611a 100644
--- a/dom/workers/ServiceWorkerClient.h
+++ b/dom/workers/ServiceWorkerClient.h
@@ -91,7 +91,13 @@ public:
 
   void
   PostMessage(JSContext* aCx, JS::Handle<JS::Value> aMessage,
-              const Optional<Sequence<JS::Value>>& aTransferable,
+              const Sequence<JSObject*>& aTransferable,
+              ErrorResult& aRv);
+
+  void
+  PostMessage(JSContext* aCx,
+              JS::Handle<JS::Value> aMessage,
+              const StructuredSerializeOptions& aOptions,
               ErrorResult& aRv);
 
   JSObject* WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override;
diff --git a/dom/workers/ServiceWorkerPrivate.cpp b/dom/workers/ServiceWorkerPrivate.cpp
index 2f5b8f7500..fe6ec138b7 100644
--- a/dom/workers/ServiceWorkerPrivate.cpp
+++ b/dom/workers/ServiceWorkerPrivate.cpp
@@ -141,7 +141,7 @@ NS_IMPL_ISUPPORTS0(MessageWaitUntilHandler)
 nsresult
 ServiceWorkerPrivate::SendMessageEvent(JSContext* aCx,
                                        JS::Handle<JS::Value> aMessage,
-                                       const Optional<Sequence<JS::Value>>& aTransferable,
+                                       const Sequence<JSObject*>& aTransferable,
                                        UniquePtr<ServiceWorkerClientInfo>&& aClientInfo)
 {
   ErrorResult rv(SpawnWorkerIfNeeded(MessageEvent, nullptr));
diff --git a/dom/workers/ServiceWorkerPrivate.h b/dom/workers/ServiceWorkerPrivate.h
index 8ce021c8cf..c2d5abfd6c 100644
--- a/dom/workers/ServiceWorkerPrivate.h
+++ b/dom/workers/ServiceWorkerPrivate.h
@@ -74,7 +74,7 @@ public:
 
   nsresult
   SendMessageEvent(JSContext* aCx, JS::Handle<JS::Value> aMessage,
-                   const Optional<Sequence<JS::Value>>& aTransferable,
+                   const Sequence<JSObject*>& aTransferable,
                    UniquePtr<ServiceWorkerClientInfo>&& aClientInfo);
 
   // This is used to validate the worker script and continue the installation
diff --git a/dom/workers/SharedWorker.cpp b/dom/workers/SharedWorker.cpp
index 97df0f57fd..2fae19f291 100644
--- a/dom/workers/SharedWorker.cpp
+++ b/dom/workers/SharedWorker.cpp
@@ -22,6 +22,7 @@
 using mozilla::dom::Optional;
 using mozilla::dom::Sequence;
 using mozilla::dom::MessagePort;
+using mozilla::dom::StructuredSerializeOptions;
 using namespace mozilla;
 
 USING_WORKERS_NAMESPACE
@@ -142,7 +143,7 @@ SharedWorker::Close()
 
 void
 SharedWorker::PostMessage(JSContext* aCx, JS::Handle<JS::Value> aMessage,
-                          const Optional<Sequence<JS::Value>>& aTransferable,
+                          const Sequence<JSObject*>& aTransferable,
                           ErrorResult& aRv)
 {
   AssertIsOnMainThread();
@@ -152,6 +153,15 @@ SharedWorker::PostMessage(JSContext* aCx, JS::Handle<JS::Value> aMessage,
   mMessagePort->PostMessage(aCx, aMessage, aTransferable, aRv);
 }
 
+void
+SharedWorker::PostMessage(JSContext* aCx,
+                          JS::Handle<JS::Value> aMessage,
+                          const StructuredSerializeOptions& aOptions,
+                          ErrorResult& aRv)
+{
+  PostMessage(aCx, aMessage, aOptions.mTransfer, aRv);
+}
+
 NS_IMPL_ADDREF_INHERITED(SharedWorker, DOMEventTargetHelper)
 NS_IMPL_RELEASE_INHERITED(SharedWorker, DOMEventTargetHelper)
 
diff --git a/dom/workers/SharedWorker.h b/dom/workers/SharedWorker.h
index 4820b4e7c1..e85fc2609a 100644
--- a/dom/workers/SharedWorker.h
+++ b/dom/workers/SharedWorker.h
@@ -94,8 +94,15 @@ private:
 
   // Only called by MessagePort.
   void
-  PostMessage(JSContext* aCx, JS::Handle<JS::Value> aMessage,
-              const Optional<Sequence<JS::Value>>& aTransferable,
+  PostMessage(JSContext* aCx,
+              JS::Handle<JS::Value> aMessage,
+              const Sequence<JSObject*>& aTransferable,
+              ErrorResult& aRv);
+
+  void
+  PostMessage(JSContext* aCx,
+              JS::Handle<JS::Value> aMessage,
+              const StructuredSerializeOptions& aOptions,
               ErrorResult& aRv);
 };
 
diff --git a/dom/workers/WorkerPrivate.cpp b/dom/workers/WorkerPrivate.cpp
index cf270703e0..a7a4929f3b 100644
--- a/dom/workers/WorkerPrivate.cpp
+++ b/dom/workers/WorkerPrivate.cpp
@@ -3006,13 +3006,12 @@ WorkerPrivateParent<Derived>::ForgetMainThreadObjects(
 
 template <class Derived>
 void
-WorkerPrivateParent<Derived>::PostMessageInternal(
-                                            JSContext* aCx,
-                                            JS::Handle<JS::Value> aMessage,
-                                            const Optional<Sequence<JS::Value>>& aTransferable,
-                                            UniquePtr<ServiceWorkerClientInfo>&& aClientInfo,
-                                            PromiseNativeHandler* aHandler,
-                                            ErrorResult& aRv)
+WorkerPrivateParent<Derived>::PostMessageInternal(JSContext* aCx,
+                                                  JS::Handle<JS::Value> aMessage,
+                                                  const Sequence<JSObject*>& aTransferable,
+                                                  UniquePtr<ServiceWorkerClientInfo>&& aClientInfo,
+                                                  PromiseNativeHandler* aHandler,
+                                                  ErrorResult& aRv)
 {
   AssertIsOnParentThread();
 
@@ -3024,22 +3023,11 @@ WorkerPrivateParent<Derived>::PostMessageInternal(
   }
 
   JS::Rooted<JS::Value> transferable(aCx, JS::UndefinedValue());
-  if (aTransferable.WasPassed()) {
-    const Sequence<JS::Value>& realTransferable = aTransferable.Value();
-
-    // The input sequence only comes from the generated bindings code, which
-    // ensures it is rooted.
-    JS::HandleValueArray elements =
-      JS::HandleValueArray::fromMarkedLocation(realTransferable.Length(),
-                                               realTransferable.Elements());
-
-    JSObject* array =
-      JS_NewArrayObject(aCx, elements);
-    if (!array) {
-      aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
-      return;
-    }
-    transferable.setObject(*array);
+  aRv = nsContentUtils::CreateJSValueFromSequenceOfObject(aCx,
+                                                          aTransferable,
+                                                          &transferable);
+  if (NS_WARN_IF(aRv.Failed())) {
+    return;
   }
 
   RefPtr<MessageEventRunnable> runnable =
@@ -3083,8 +3071,9 @@ WorkerPrivateParent<Derived>::PostMessageInternal(
 template <class Derived>
 void
 WorkerPrivateParent<Derived>::PostMessage(
-                             JSContext* aCx, JS::Handle<JS::Value> aMessage,
-                             const Optional<Sequence<JS::Value>>& aTransferable,
+                             JSContext* aCx,
+                             JS::Handle<JS::Value> aMessage,
+                             const Sequence<JSObject*>& aTransferable,
                              ErrorResult& aRv)
 {
   PostMessageInternal(aCx, aMessage, aTransferable, nullptr, nullptr, aRv);
@@ -3092,9 +3081,21 @@ WorkerPrivateParent<Derived>::PostMessage(
 
 template <class Derived>
 void
+WorkerPrivateParent<Derived>::PostMessage(
+                             JSContext* aCx,
+                             JS::Handle<JS::Value> aMessage,
+                             const StructuredSerializeOptions& aOptions,
+                             ErrorResult& aRv)
+{
+  PostMessageInternal(aCx, aMessage, aOptions.mTransfer, nullptr, nullptr, aRv);
+}
+
+template <class Derived>
+void
 WorkerPrivateParent<Derived>::PostMessageToServiceWorker(
-                             JSContext* aCx, JS::Handle<JS::Value> aMessage,
-                             const Optional<Sequence<JS::Value>>& aTransferable,
+                             JSContext* aCx,
+                             JS::Handle<JS::Value> aMessage,
+                             const Sequence<JSObject*>& aTransferable,
                              UniquePtr<ServiceWorkerClientInfo>&& aClientInfo,
                              PromiseNativeHandler* aHandler,
                              ErrorResult& aRv)
@@ -5677,27 +5678,17 @@ void
 WorkerPrivate::PostMessageToParentInternal(
                             JSContext* aCx,
                             JS::Handle<JS::Value> aMessage,
-                            const Optional<Sequence<JS::Value>>& aTransferable,
+                            const Sequence<JSObject*>& aTransferable,
                             ErrorResult& aRv)
 {
   AssertIsOnWorkerThread();
 
   JS::Rooted<JS::Value> transferable(aCx, JS::UndefinedValue());
-  if (aTransferable.WasPassed()) {
-    const Sequence<JS::Value>& realTransferable = aTransferable.Value();
-
-    // The input sequence only comes from the generated bindings code, which
-    // ensures it is rooted.
-    JS::HandleValueArray elements =
-      JS::HandleValueArray::fromMarkedLocation(realTransferable.Length(),
-                                               realTransferable.Elements());
-
-    JSObject* array = JS_NewArrayObject(aCx, elements);
-    if (!array) {
-      aRv = NS_ERROR_OUT_OF_MEMORY;
-      return;
-    }
-    transferable.setObject(*array);
+  aRv = nsContentUtils::CreateJSValueFromSequenceOfObject(aCx,
+                                                          aTransferable,
+                                                          &transferable);
+  if (NS_WARN_IF(aRv.Failed())) {
+    return;
   }
 
   RefPtr<MessageEventRunnable> runnable =
diff --git a/dom/workers/WorkerPrivate.h b/dom/workers/WorkerPrivate.h
index b638c1ef11..0a71420047 100644
--- a/dom/workers/WorkerPrivate.h
+++ b/dom/workers/WorkerPrivate.h
@@ -68,6 +68,7 @@ class PromiseNativeHandler;
 class StructuredCloneHolder;
 class WorkerDebuggerGlobalScope;
 class WorkerGlobalScope;
+struct StructuredSerializeOptions;
 } // namespace dom
 namespace ipc {
 class PrincipalInfo;
@@ -287,7 +288,7 @@ private:
 
   void
   PostMessageInternal(JSContext* aCx, JS::Handle<JS::Value> aMessage,
-                      const Optional<Sequence<JS::Value>>& aTransferable,
+                      const Sequence<JSObject*>& aTransferable,
                       UniquePtr<ServiceWorkerClientInfo>&& aClientInfo,
                       PromiseNativeHandler* aHandler,
                       ErrorResult& aRv);
@@ -400,12 +401,18 @@ public:
 
   void
   PostMessage(JSContext* aCx, JS::Handle<JS::Value> aMessage,
-              const Optional<Sequence<JS::Value>>& aTransferable,
+              const Sequence<JSObject*>& aTransferable,
+              ErrorResult& aRv);
+
+  void
+  PostMessage(JSContext* aCx,
+              JS::Handle<JS::Value> aMessage,
+              const StructuredSerializeOptions& aOptions,
               ErrorResult& aRv);
 
   void
   PostMessageToServiceWorker(JSContext* aCx, JS::Handle<JS::Value> aMessage,
-                             const Optional<Sequence<JS::Value>>& aTransferable,
+                             const Sequence<JSObject*>& aTransferable,
                              UniquePtr<ServiceWorkerClientInfo>&& aClientInfo,
                              PromiseNativeHandler* aHandler,
                              ErrorResult& aRv);
@@ -1161,18 +1168,17 @@ public:
   void
   PostMessageToParent(JSContext* aCx,
                       JS::Handle<JS::Value> aMessage,
-                      const Optional<Sequence<JS::Value>>& aTransferable,
+                      const Sequence<JSObject*>& aTransferable,
                       ErrorResult& aRv)
   {
     PostMessageToParentInternal(aCx, aMessage, aTransferable, aRv);
   }
 
   void
-  PostMessageToParentMessagePort(
-                             JSContext* aCx,
-                             JS::Handle<JS::Value> aMessage,
-                             const Optional<Sequence<JS::Value>>& aTransferable,
-                             ErrorResult& aRv);
+  PostMessageToParentMessagePort(JSContext* aCx,
+                                 JS::Handle<JS::Value> aMessage,
+                                 const Sequence<JSObject*>& aTransferable,
+                                 ErrorResult& aRv);
 
   void
   EnterDebuggerEventLoop();
@@ -1471,7 +1477,7 @@ private:
   void
   PostMessageToParentInternal(JSContext* aCx,
                               JS::Handle<JS::Value> aMessage,
-                              const Optional<Sequence<JS::Value>>& aTransferable,
+                              const Sequence<JSObject*>& aTransferable,
                               ErrorResult& aRv);
 
   void
diff --git a/dom/workers/WorkerScope.cpp b/dom/workers/WorkerScope.cpp
index ec42364b52..637e441732 100644
--- a/dom/workers/WorkerScope.cpp
+++ b/dom/workers/WorkerScope.cpp
@@ -7,6 +7,7 @@
 
 #include "jsapi.h"
 #include "mozilla/EventListenerManager.h"
+#include "mozilla/Unused.h"
 #include "mozilla/dom/BindingDeclarations.h"
 #include "mozilla/dom/Console.h"
 #include "mozilla/dom/DedicatedWorkerGlobalScopeBinding.h"
@@ -492,6 +493,15 @@ WorkerGlobalScope::CreateImageBitmap(const ImageBitmapSource& aImage,
   }
 }
 
+// https://html.spec.whatwg.org/#structured-cloning
+void WorkerGlobalScope::StructuredClone(JSContext* aCx,
+                                        JS::Handle<JS::Value> aValue,
+                                        const StructuredSerializeOptions& aOptions,
+                                        JS::MutableHandle<JS::Value> aRv,
+                                        ErrorResult& aError) {
+  nsContentUtils::StructuredClone(aCx, this, aValue, aOptions, aRv, aError);
+}
+
 DedicatedWorkerGlobalScope::DedicatedWorkerGlobalScope(WorkerPrivate* aWorkerPrivate)
 : WorkerGlobalScope(aWorkerPrivate)
 {
@@ -535,13 +545,22 @@ DedicatedWorkerGlobalScope::WrapGlobalObject(JSContext* aCx,
 void
 DedicatedWorkerGlobalScope::PostMessage(JSContext* aCx,
                                         JS::Handle<JS::Value> aMessage,
-                                        const Optional<Sequence<JS::Value>>& aTransferable,
+                                        const Sequence<JSObject*>& aTransferable,
                                         ErrorResult& aRv)
 {
   mWorkerPrivate->AssertIsOnWorkerThread();
   mWorkerPrivate->PostMessageToParent(aCx, aMessage, aTransferable, aRv);
 }
 
+void
+DedicatedWorkerGlobalScope::PostMessage(JSContext* aCx,
+                                        JS::Handle<JS::Value> aMessage,
+                                        const StructuredSerializeOptions& aOptions,
+                                        ErrorResult& aRv)
+{
+  PostMessage(aCx, aMessage, aOptions.mTransfer, aRv);
+}
+
 SharedWorkerGlobalScope::SharedWorkerGlobalScope(WorkerPrivate* aWorkerPrivate,
                                                  const nsCString& aName)
 : WorkerGlobalScope(aWorkerPrivate), mName(aName)
diff --git a/dom/workers/WorkerScope.h b/dom/workers/WorkerScope.h
index 8d06152da2..01bae5cc11 100644
--- a/dom/workers/WorkerScope.h
+++ b/dom/workers/WorkerScope.h
@@ -24,6 +24,7 @@ class Function;
 class IDBFactory;
 enum class ImageBitmapFormat : uint32_t;
 class Performance;
+struct StructuredSerializeOptions;
 class Promise;
 class RequestOrUSVString;
 class ServiceWorkerRegistration;
@@ -182,6 +183,11 @@ public:
                     const mozilla::dom::Sequence<mozilla::dom::ChannelPixelLayout>& aLayout,
                     mozilla::ErrorResult& aRv);
 
+  void StructuredClone(JSContext* aCx, JS::Handle<JS::Value> aValue,
+                       const StructuredSerializeOptions& aOptions,
+                       JS::MutableHandle<JS::Value> aRv,
+                       ErrorResult& aError);
+
   bool
   WindowInteractionAllowed() const
   {
@@ -215,7 +221,13 @@ public:
 
   void
   PostMessage(JSContext* aCx, JS::Handle<JS::Value> aMessage,
-              const Optional<Sequence<JS::Value>>& aTransferable,
+              const Sequence<JSObject*>& aTransferable,
+              ErrorResult& aRv);
+
+  void
+  PostMessage(JSContext* aCx,
+              JS::Handle<JS::Value> aMessage,
+              const StructuredSerializeOptions& aOptions,
               ErrorResult& aRv);
 
   IMPL_EVENT_HANDLER(message)