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/task_source/port_message.rs

@@ -0,0 +1,45 @@
+/* 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::script_runtime::{CommonScriptMsg, ScriptChan, ScriptThreadEventCategory};
+use crate::task::{TaskCanceller, TaskOnce};
+use crate::task_source::{TaskSource, TaskSourceName};
+use msg::constellation_msg::PipelineId;
+use std::fmt;
+
+#[derive(JSTraceable)]
+pub struct PortMessageQueue(pub Box<ScriptChan + Send + 'static>, pub PipelineId);
+
+impl Clone for PortMessageQueue {
+    fn clone(&self) -> PortMessageQueue {
+        PortMessageQueue(self.0.clone(), self.1.clone())
+    }
+}
+
+impl fmt::Debug for PortMessageQueue {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "PortMessageQueue(...)")
+    }
+}
+
+impl TaskSource for PortMessageQueue {
+    const NAME: TaskSourceName = TaskSourceName::PortMessage;
+
+    fn queue_with_canceller<T>(
+        &self,
+        task: T,
+        canceller: &TaskCanceller,
+    ) -> Result<(), ()>
+    where
+        T: TaskOnce + 'static,
+    {
+        let msg = CommonScriptMsg::Task(
+            ScriptThreadEventCategory::PortMessage,
+            Box::new(canceller.wrap_task(task)),
+            Some(self.1),
+            Self::NAME,
+        );
+        self.0.send(msg).map_err(|_| ())
+    }
+}