begin messageport, transferable objects, impl

Accept transfer argument for StructuredCloneData::write

Allow structured clone reads to return a boolean

Add Transferable trait

Add basic skeletons to MessagePort

Implement transfer and transfer-receiving steps on MessagePort

Use transfer and transfer_receive in StructuredClone callbacks

Implement MessageChannel

Freeze the array object for the MessageEvent ports attribute

Implement transfer argument on window.postMessage

Use ReentrantMutex instead for MessagePortInternal

Accept origin as a parameter in dispatch_jsval

Fix BorrowMut crash with pending_port_message

Detach port on closure and check for detached during transfer

Enable webmessaging tests

fix webidl

fix

components/script/dom/messagechannel.rs

@@ -0,0 +1,60 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use crate::dom::bindings::codegen::Bindings::MessageChannelBinding::{MessageChannelMethods, Wrap};
+use crate::dom::bindings::error::{Error, Fallible};
+use crate::dom::bindings::reflector::{Reflector, reflect_dom_object};
+use crate::dom::bindings::root::{Dom, DomRoot};
+use crate::dom::globalscope::GlobalScope;
+use crate::dom::messageport::MessagePort;
+use dom_struct::dom_struct;
+
+#[dom_struct]
+pub struct MessageChannel {
+    reflector_: Reflector,
+    port1: Dom<MessagePort>,
+    port2: Dom<MessagePort>,
+}
+
+impl MessageChannel {
+    /// <https://html.spec.whatwg.org/multipage/#dom-messagechannel>
+    pub fn Constructor(global: &GlobalScope) -> Fallible<DomRoot<MessageChannel>> {
+        let incumbent = GlobalScope::incumbent().ok_or(Error::InvalidState)?;
+
+        // Step 1
+        let port1 = MessagePort::new(&incumbent);
+
+        // Step 2
+        let port2 = MessagePort::new(&incumbent);
+
+        // Step 3
+        port1.entangle(&port2);
+
+        // Steps 4-6
+        let channel = reflect_dom_object(Box::new(
+            MessageChannel {
+                reflector_: Reflector::new(),
+                port1: Dom::from_ref(&port1),
+                port2: Dom::from_ref(&port2),
+            }),
+            global,
+            Wrap
+        );
+
+        // Step 7
+        Ok(channel)
+    }
+}
+
+impl MessageChannelMethods for MessageChannel {
+    /// <https://html.spec.whatwg.org/multipage/#dom-messagechannel-port1>
+    fn Port1(&self) -> DomRoot<MessagePort> {
+        DomRoot::from_ref(&*self.port1)
+    }
+
+    /// <https://html.spec.whatwg.org/multipage/#dom-messagechannel-port2>
+    fn Port2(&self) -> DomRoot<MessagePort> {
+        DomRoot::from_ref(&*self.port2)
+    }
+}