Auto merge of #7006 - Wafflespeanut:script_cleanup, r=jdm

Splitting ScriptMsg into various enums...

... for #3734, which is also one of the oldest issues. (/cc @jdm)

<!-- Reviewable:start -->
[<img src="https://reviewable.io/review_button.png" height=40 alt="Review on Reviewable"/>](https://reviewable.io/reviews/servo/servo/7006)
<!-- Reviewable:end -->

components/script/document_loader.rs

@@ -5,11 +5,12 @@
 //! Tracking of pending loads in a document.
 //! https://html.spec.whatwg.org/multipage/#the-end
 
-use script_task::{ScriptMsg, ScriptChan};
+use script_task::MainThreadScriptMsg;
 use msg::constellation_msg::{PipelineId};
 use net_traits::{Metadata, load_whole_resource, ResourceTask, PendingAsyncLoad};
 use net_traits::AsyncResponseTarget;
 use std::sync::Arc;
+use std::sync::mpsc::Sender;
 use url::Url;
 
 #[derive(JSTraceable, PartialEq, Clone, Debug, HeapSizeOf)]
@@ -46,7 +47,7 @@ pub struct DocumentLoader {
 #[derive(JSTraceable, HeapSizeOf)]
 pub struct NotifierData {
     #[ignore_heap_size_of = "trait objects are hard"]
-    pub script_chan: Box<ScriptChan + Send>,
+    pub script_chan: Sender<MainThreadScriptMsg>,
     pub pipeline: PipelineId,
 }
 
@@ -100,7 +101,7 @@ impl DocumentLoader {
 
         if let Some(NotifierData { ref script_chan, pipeline }) = self.notifier_data {
             if !self.is_blocked() {
-                script_chan.send(ScriptMsg::DocumentLoadsComplete(pipeline)).unwrap();
+                script_chan.send(MainThreadScriptMsg::DocumentLoadsComplete(pipeline)).unwrap();
             }
         }
     }

components/script/dom/bindings/global.rs

@@ -15,7 +15,7 @@ use dom::document::DocumentHelpers;
 use dom::workerglobalscope::{WorkerGlobalScope, WorkerGlobalScopeHelpers};
 use dom::window::{self, WindowHelpers, ScriptHelpers};
 use devtools_traits::ScriptToDevtoolsControlMsg;
-use script_task::{ScriptChan, ScriptPort, ScriptMsg, ScriptTask};
+use script_task::{ScriptChan, ScriptPort, CommonScriptMsg, ScriptTask};
 
 use msg::constellation_msg::{ConstellationChan, PipelineId, WorkerId};
 use net_traits::ResourceTask;
@@ -168,7 +168,7 @@ impl<'a> GlobalRef<'a> {
 
     /// Process a single event as if it were the next event in the task queue for
     /// this global.
-    pub fn process_event(&self, msg: ScriptMsg) {
+    pub fn process_event(&self, msg: CommonScriptMsg) {
         match *self {
             GlobalRef::Window(_) => ScriptTask::process_event(msg),
             GlobalRef::Worker(ref worker) => worker.process_event(msg),

components/script/dom/bindings/refcounted.rs

@@ -25,7 +25,7 @@
 use dom::bindings::js::Root;
 use dom::bindings::utils::{Reflector, Reflectable};
 use dom::bindings::trace::trace_reflector;
-use script_task::{ScriptMsg, ScriptChan};
+use script_task::{ScriptChan, CommonScriptMsg};
 
 use js::jsapi::{JSContext, JSTracer};
 
@@ -130,7 +130,7 @@ impl<T: Reflectable> Drop for Trusted<T> {
             // It's possible this send will fail if the script task
             // has already exited. There's not much we can do at this
             // point though.
-            let msg = ScriptMsg::RefcountCleanup(TrustedReference(self.ptr));
+            let msg = CommonScriptMsg::RefcountCleanup(TrustedReference(self.ptr));
             let _ = self.script_chan.send(msg);
         }
     }

components/script/dom/dedicatedworkerglobalscope.rs

@@ -22,8 +22,7 @@ use dom::messageevent::MessageEvent;
 use dom::worker::{TrustedWorkerAddress, WorkerMessageHandler, WorkerEventHandler, WorkerErrorHandler};
 use dom::workerglobalscope::{WorkerGlobalScope, WorkerGlobalScopeHelpers};
 use dom::workerglobalscope::{WorkerGlobalScopeTypeId, WorkerGlobalScopeInit};
-use script_task::{ScriptTask, ScriptChan, ScriptMsg, TimerSource, ScriptPort};
+use script_task::{ScriptTask, ScriptChan, TimerSource, ScriptPort, StackRootTLS, CommonScriptMsg};
-use script_task::StackRootTLS;
 
 use devtools_traits::DevtoolScriptControlMsg;
 use msg::constellation_msg::PipelineId;
@@ -45,17 +44,25 @@ use std::mem::replace;
 use std::rc::Rc;
 use std::sync::mpsc::{Sender, Receiver, channel, Select, RecvError};
 
+/// Messages used to control the worker event loops
+pub enum WorkerScriptMsg {
+    /// Common variants associated with the script messages
+    Common(CommonScriptMsg),
+    /// Message sent through Worker.postMessage
+    DOMMessage(StructuredCloneData),
+}
+
 /// A ScriptChan that can be cloned freely and will silently send a TrustedWorkerAddress with
-/// every message. While this SendableWorkerScriptChan is alive, the associated Worker object
+/// common event loop messages. While this SendableWorkerScriptChan is alive, the associated
-/// will remain alive.
+/// Worker object will remain alive.
 #[derive(JSTraceable, Clone)]
 pub struct SendableWorkerScriptChan {
-    sender: Sender<(TrustedWorkerAddress, ScriptMsg)>,
+    sender: Sender<(TrustedWorkerAddress, CommonScriptMsg)>,
     worker: TrustedWorkerAddress,
 }
 
 impl ScriptChan for SendableWorkerScriptChan {
-    fn send(&self, msg: ScriptMsg) -> Result<(), ()> {
+    fn send(&self, msg: CommonScriptMsg) -> Result<(), ()> {
         return self.sender.send((self.worker.clone(), msg)).map_err(|_| ());
     }
 
@@ -67,6 +74,39 @@ impl ScriptChan for SendableWorkerScriptChan {
     }
 }
 
+/// A ScriptChan that can be cloned freely and will silently send a TrustedWorkerAddress with
+/// worker event loop messages. While this SendableWorkerScriptChan is alive, the associated
+/// Worker object will remain alive.
+#[derive(JSTraceable, Clone)]
+pub struct WorkerThreadWorkerChan {
+    sender: Sender<(TrustedWorkerAddress, WorkerScriptMsg)>,
+    worker: TrustedWorkerAddress,
+}
+
+impl ScriptChan for WorkerThreadWorkerChan {
+    fn send(&self, msg: CommonScriptMsg) -> Result<(), ()> {
+        return self.sender
+            .send((self.worker.clone(), WorkerScriptMsg::Common(msg)))
+            .map_err(|_| ());
+    }
+
+    fn clone(&self) -> Box<ScriptChan + Send> {
+        box WorkerThreadWorkerChan {
+            sender: self.sender.clone(),
+            worker: self.worker.clone(),
+        }
+    }
+}
+
+impl ScriptPort for Receiver<(TrustedWorkerAddress, WorkerScriptMsg)> {
+    fn recv(&self) -> CommonScriptMsg {
+        match self.recv().unwrap().1 {
+            WorkerScriptMsg::Common(script_msg) => script_msg,
+            WorkerScriptMsg::DOMMessage(_) => panic!("unexpected worker event message!"),
+        }
+    }
+}
+
 /// Set the `worker` field of a related DedicatedWorkerGlobalScope object to a particular
 /// value for the duration of this object's lifetime. This ensures that the related Worker
 /// object only lives as long as necessary (ie. while events are being executed), while
@@ -92,7 +132,7 @@ impl<'a> Drop for AutoWorkerReset<'a> {
 }
 
 enum MixedMessage {
-    FromWorker((TrustedWorkerAddress, ScriptMsg)),
+    FromWorker((TrustedWorkerAddress, WorkerScriptMsg)),
     FromDevtools(DevtoolScriptControlMsg),
 }
 
@@ -103,9 +143,9 @@ pub struct DedicatedWorkerGlobalScope {
     workerglobalscope: WorkerGlobalScope,
     id: PipelineId,
     #[ignore_heap_size_of = "Defined in std"]
-    receiver: Receiver<(TrustedWorkerAddress, ScriptMsg)>,
+    receiver: Receiver<(TrustedWorkerAddress, WorkerScriptMsg)>,
     #[ignore_heap_size_of = "Defined in std"]
-    own_sender: Sender<(TrustedWorkerAddress, ScriptMsg)>,
+    own_sender: Sender<(TrustedWorkerAddress, WorkerScriptMsg)>,
     #[ignore_heap_size_of = "Trusted<T> has unclear ownership like JS<T>"]
     worker: DOMRefCell<Option<TrustedWorkerAddress>>,
     #[ignore_heap_size_of = "Can't measure trait objects"]
@@ -120,8 +160,8 @@ impl DedicatedWorkerGlobalScope {
                      devtools_port: Receiver<DevtoolScriptControlMsg>,
                      runtime: Rc<Runtime>,
                      parent_sender: Box<ScriptChan+Send>,
-                     own_sender: Sender<(TrustedWorkerAddress, ScriptMsg)>,
+                     own_sender: Sender<(TrustedWorkerAddress, WorkerScriptMsg)>,
-                     receiver: Receiver<(TrustedWorkerAddress, ScriptMsg)>)
+                     receiver: Receiver<(TrustedWorkerAddress, WorkerScriptMsg)>)
                      -> DedicatedWorkerGlobalScope {
         DedicatedWorkerGlobalScope {
             workerglobalscope: WorkerGlobalScope::new_inherited(
@@ -141,8 +181,8 @@ impl DedicatedWorkerGlobalScope {
                devtools_port: Receiver<DevtoolScriptControlMsg>,
                runtime: Rc<Runtime>,
                parent_sender: Box<ScriptChan+Send>,
-               own_sender: Sender<(TrustedWorkerAddress, ScriptMsg)>,
+               own_sender: Sender<(TrustedWorkerAddress, WorkerScriptMsg)>,
-               receiver: Receiver<(TrustedWorkerAddress, ScriptMsg)>)
+               receiver: Receiver<(TrustedWorkerAddress, WorkerScriptMsg)>)
                -> Root<DedicatedWorkerGlobalScope> {
         let scope = box DedicatedWorkerGlobalScope::new_inherited(
             init, worker_url, id, devtools_port, runtime.clone(), parent_sender,
@@ -158,8 +198,8 @@ impl DedicatedWorkerGlobalScope {
                             devtools_ipc_port: IpcReceiver<DevtoolScriptControlMsg>,
                             worker: TrustedWorkerAddress,
                             parent_sender: Box<ScriptChan+Send>,
-                            own_sender: Sender<(TrustedWorkerAddress, ScriptMsg)>,
+                            own_sender: Sender<(TrustedWorkerAddress, WorkerScriptMsg)>,
-                            receiver: Receiver<(TrustedWorkerAddress, ScriptMsg)>) {
+                            receiver: Receiver<(TrustedWorkerAddress, WorkerScriptMsg)>) {
         let serialized_worker_url = worker_url.serialize();
         spawn_named(format!("WebWorker for {}", serialized_worker_url), move || {
             task_state::initialize(SCRIPT | IN_WORKER);
@@ -170,7 +210,7 @@ impl DedicatedWorkerGlobalScope {
             let (url, source) = match load_whole_resource(&init.resource_task, worker_url) {
                 Err(_) => {
                     println!("error loading script {}", serialized_worker_url);
-                    parent_sender.send(ScriptMsg::RunnableMsg(
+                    parent_sender.send(CommonScriptMsg::RunnableMsg(
                         box WorkerEventHandler::new(worker))).unwrap();
                     return;
                 }
@@ -201,7 +241,7 @@ impl DedicatedWorkerGlobalScope {
                 while let Ok(event) = global.receive_event() {
                     global.handle_event(event);
                 }
-            }, reporter_name, parent_sender, ScriptMsg::CollectReports);
+            }, reporter_name, parent_sender, CommonScriptMsg::CollectReports);
         });
     }
 }
@@ -210,12 +250,12 @@ pub trait DedicatedWorkerGlobalScopeHelpers {
     fn script_chan(self) -> Box<ScriptChan+Send>;
     fn pipeline(self) -> PipelineId;
     fn new_script_pair(self) -> (Box<ScriptChan+Send>, Box<ScriptPort+Send>);
-    fn process_event(self, msg: ScriptMsg);
+    fn process_event(self, msg: CommonScriptMsg);
 }
 
 impl<'a> DedicatedWorkerGlobalScopeHelpers for &'a DedicatedWorkerGlobalScope {
     fn script_chan(self) -> Box<ScriptChan+Send> {
-        box SendableWorkerScriptChan {
+        box WorkerThreadWorkerChan {
             sender: self.own_sender.clone(),
             worker: self.worker.borrow().as_ref().unwrap().clone(),
         }
@@ -234,13 +274,13 @@ impl<'a> DedicatedWorkerGlobalScopeHelpers for &'a DedicatedWorkerGlobalScope {
         (chan, box rx)
     }
 
-    fn process_event(self, msg: ScriptMsg) {
+    fn process_event(self, msg: CommonScriptMsg) {
-        self.handle_script_event(msg);
+        self.handle_script_event(WorkerScriptMsg::Common(msg));
     }
 }
 
 trait PrivateDedicatedWorkerGlobalScopeHelpers {
-    fn handle_script_event(self, msg: ScriptMsg);
+    fn handle_script_event(self, msg: WorkerScriptMsg);
     fn dispatch_error_to_worker(self, &ErrorEvent);
     fn receive_event(self) -> Result<MixedMessage, RecvError>;
     fn handle_event(self, event: MixedMessage);
@@ -272,9 +312,9 @@ impl<'a> PrivateDedicatedWorkerGlobalScopeHelpers for &'a DedicatedWorkerGlobalS
         }
     }
 
-    fn handle_script_event(self, msg: ScriptMsg) {
+    fn handle_script_event(self, msg: WorkerScriptMsg) {
         match msg {
-            ScriptMsg::DOMMessage(data) => {
+            WorkerScriptMsg::DOMMessage(data) => {
                 let scope = WorkerGlobalScopeCast::from_ref(self);
                 let target = EventTargetCast::from_ref(self);
                 let _ar = JSAutoRequest::new(scope.get_cx());
@@ -283,24 +323,27 @@ impl<'a> PrivateDedicatedWorkerGlobalScopeHelpers for &'a DedicatedWorkerGlobalS
                 data.read(GlobalRef::Worker(scope), message.handle_mut());
                 MessageEvent::dispatch_jsval(target, GlobalRef::Worker(scope), message.handle());
             },
-            ScriptMsg::RunnableMsg(runnable) => {
+            WorkerScriptMsg::Common(CommonScriptMsg::RunnableMsg(runnable)) => {
                 runnable.handler()
             },
-            ScriptMsg::RefcountCleanup(addr) => {
+            WorkerScriptMsg::Common(CommonScriptMsg::RefcountCleanup(addr)) => {
                 LiveDOMReferences::cleanup(addr);
-            }
+            },
-            ScriptMsg::FireTimer(TimerSource::FromWorker, timer_id) => {
+            WorkerScriptMsg::Common(
+                CommonScriptMsg::FireTimer(TimerSource::FromWorker, timer_id)) => {
                 let scope = WorkerGlobalScopeCast::from_ref(self);
                 scope.handle_fire_timer(timer_id);
-            }
+            },
-            ScriptMsg::CollectReports(reports_chan) => {
+            WorkerScriptMsg::Common(CommonScriptMsg::CollectReports(reports_chan)) => {
                 let scope = WorkerGlobalScopeCast::from_ref(self);
                 let cx = scope.get_cx();
                 let path_seg = format!("url({})", scope.get_url());
                 let reports = ScriptTask::get_reports(cx, path_seg);
                 reports_chan.send(reports);
-            }
+            },
-            _ => panic!("Unexpected message"),
+            WorkerScriptMsg::Common(CommonScriptMsg::FireTimer(_, _)) => {
+                panic!("obtained a fire timeout from window for the worker!")
+            },
         }
     }
 
@@ -331,7 +374,7 @@ impl<'a> PrivateDedicatedWorkerGlobalScopeHelpers for &'a DedicatedWorkerGlobalS
         let line_num = errorevent.Lineno();
         let col_num = errorevent.Colno();
         let worker = self.worker.borrow().as_ref().unwrap().clone();
-        self.parent_sender.send(ScriptMsg::RunnableMsg(
+        self.parent_sender.send(CommonScriptMsg::RunnableMsg(
             box WorkerErrorHandler::new(worker, msg, file_name, line_num, col_num))).unwrap();
  }
 }
@@ -341,7 +384,7 @@ impl<'a> DedicatedWorkerGlobalScopeMethods for &'a DedicatedWorkerGlobalScope {
     fn PostMessage(self, cx: *mut JSContext, message: HandleValue) -> ErrorResult {
         let data = try!(StructuredCloneData::write(cx, message));
         let worker = self.worker.borrow().as_ref().unwrap().clone();
-        self.parent_sender.send(ScriptMsg::RunnableMsg(
+        self.parent_sender.send(CommonScriptMsg::RunnableMsg(
             box WorkerMessageHandler::new(worker, data))).unwrap();
         Ok(())
     }

components/script/dom/filereader.rs

@@ -22,7 +22,7 @@ use encoding::types::{EncodingRef, DecoderTrap};
 use encoding::label::encoding_from_whatwg_label;
 use hyper::mime::{Mime, Attr};
 use std::sync::mpsc;
-use script_task::{ScriptChan, ScriptMsg, Runnable, ScriptPort};
+use script_task::{ScriptChan, Runnable, ScriptPort, CommonScriptMsg};
 use std::cell::{Cell, RefCell};
 use std::sync::mpsc::Receiver;
 use util::str::DOMString;
@@ -408,22 +408,22 @@ fn perform_annotated_read_operation(gen_id: GenerationId, data: ReadMetaData, bl
     let chan = &script_chan;
     // Step 4
     let task = box FileReaderEvent::ProcessRead(filereader.clone(), gen_id);
-    chan.send(ScriptMsg::RunnableMsg(task)).unwrap();
+    chan.send(CommonScriptMsg::RunnableMsg(task)).unwrap();
 
     let task = box FileReaderEvent::ProcessReadData(filereader.clone(),
         gen_id, DOMString::new());
-    chan.send(ScriptMsg::RunnableMsg(task)).unwrap();
+    chan.send(CommonScriptMsg::RunnableMsg(task)).unwrap();
 
     let bytes = match blob_contents.recv() {
         Ok(bytes) => bytes,
         Err(_) => {
             let task = box FileReaderEvent::ProcessReadError(filereader,
                 gen_id, DOMErrorName::NotFoundError);
-            chan.send(ScriptMsg::RunnableMsg(task)).unwrap();
+            chan.send(CommonScriptMsg::RunnableMsg(task)).unwrap();
             return;
         }
     };
 
     let task = box FileReaderEvent::ProcessReadEOF(filereader, gen_id, data, bytes);
-    chan.send(ScriptMsg::RunnableMsg(task)).unwrap();
+    chan.send(CommonScriptMsg::RunnableMsg(task)).unwrap();
 }

components/script/dom/htmlformelement.rs

@@ -34,7 +34,7 @@ use hyper::header::ContentType;
 use hyper::mime;
 use msg::constellation_msg::LoadData;
 use util::str::DOMString;
-use script_task::{ScriptChan, ScriptMsg};
+use script_task::{ScriptChan, MainThreadScriptMsg};
 use url::UrlParser;
 use url::form_urlencoded::serialize;
 use string_cache::Atom;
@@ -232,7 +232,8 @@ impl<'a> HTMLFormElementHelpers for &'a HTMLFormElement {
         }
 
         // This is wrong. https://html.spec.whatwg.org/multipage/#planned-navigation
-        win.r().script_chan().send(ScriptMsg::Navigate(win.r().pipeline(), load_data)).unwrap();
+        win.r().main_thread_script_chan().send(MainThreadScriptMsg::Navigate(
+            win.r().pipeline(), load_data)).unwrap();
     }
 
     fn get_form_dataset<'b>(self, submitter: Option<FormSubmitter<'b>>) -> Vec<FormDatum> {

components/script/dom/htmlimageelement.rs

@@ -23,7 +23,7 @@ use dom::htmlelement::{HTMLElement, HTMLElementTypeId};
 use dom::node::{document_from_node, Node, NodeTypeId, NodeHelpers, NodeDamage, window_from_node};
 use dom::virtualmethods::VirtualMethods;
 use dom::window::WindowHelpers;
-use script_task::{Runnable, ScriptChan, ScriptMsg};
+use script_task::{Runnable, ScriptChan, CommonScriptMsg};
 use util::str::DOMString;
 use string_cache::Atom;
 
@@ -140,9 +140,9 @@ impl<'a> PrivateHTMLImageElementHelpers for &'a HTMLImageElement {
                     // Return the image via a message to the script task, which marks the element
                     // as dirty and triggers a reflow.
                     let image_response = message.to().unwrap();
-                    script_chan.send(ScriptMsg::RunnableMsg(box ImageResponseHandlerRunnable::new(
+                    script_chan.send(CommonScriptMsg::RunnableMsg(
-                                trusted_node.clone(),
+                        box ImageResponseHandlerRunnable::new(
-                                image_response))).unwrap();
+                            trusted_node.clone(), image_response))).unwrap();
                 });
 
                 image_cache.request_image(img_url,
@@ -345,4 +345,3 @@ impl<'a> VirtualMethods for &'a HTMLImageElement {
         }
     }
 }
-

components/script/dom/htmlscriptelement.rs

@@ -33,7 +33,7 @@ use dom::servohtmlparser::ServoHTMLParserHelpers;
 use dom::virtualmethods::VirtualMethods;
 use dom::window::{WindowHelpers, ScriptHelpers};
 use network_listener::{NetworkListener, PreInvoke};
-use script_task::{ScriptChan, ScriptMsg, Runnable};
+use script_task::{ScriptChan, Runnable, CommonScriptMsg};
 use js::jsapi::RootedValue;
 use js::jsval::UndefinedValue;
 
@@ -459,7 +459,7 @@ impl<'a> HTMLScriptElementHelpers for &'a HTMLScriptElement {
                 element: handler,
                 is_error: false,
             };
-            chan.send(ScriptMsg::RunnableMsg(dispatcher)).unwrap();
+            chan.send(CommonScriptMsg::RunnableMsg(dispatcher)).unwrap();
         }
     }
 
@@ -472,7 +472,7 @@ impl<'a> HTMLScriptElementHelpers for &'a HTMLScriptElement {
             element: handler,
             is_error: true,
         };
-        chan.send(ScriptMsg::RunnableMsg(dispatcher)).unwrap();
+        chan.send(CommonScriptMsg::RunnableMsg(dispatcher)).unwrap();
     }
 
     fn dispatch_before_script_execute_event(self) -> bool {

components/script/dom/htmltextareaelement.rs

@@ -28,7 +28,7 @@ use dom::node::{NodeHelpers, NodeTypeId, document_from_node, window_from_node};
 use textinput::{TextInput, Lines, KeyReaction};
 use dom::virtualmethods::VirtualMethods;
 use dom::window::WindowHelpers;
-use script_task::{ScriptMsg, Runnable};
+use script_task::{Runnable, CommonScriptMsg};
 use msg::constellation_msg::ConstellationChan;
 
 use util::str::DOMString;
@@ -368,7 +368,7 @@ impl<'a> VirtualMethods for &'a HTMLTextAreaElement {
                             let dispatcher = ChangeEventRunnable {
                                 element: handler,
                             };
-                            let _ = chan.send(ScriptMsg::RunnableMsg(box dispatcher));
+                            let _ = chan.send(CommonScriptMsg::RunnableMsg(box dispatcher));
                         }
 
                         self.force_relayout();

components/script/dom/storage.rs

@@ -17,12 +17,11 @@ use ipc_channel::ipc;
 use util::str::DOMString;
 use page::IterablePage;
 use net_traits::storage_task::{StorageTask, StorageTaskMsg, StorageType};
+use script_task::{ScriptTask, MainThreadRunnable, MainThreadScriptMsg};
 use std::borrow::ToOwned;
 use std::sync::mpsc::channel;
 use url::Url;
 
-use script_task::{ScriptTask, ScriptMsg, MainThreadRunnable};
-
 #[dom_struct]
 #[derive(HeapSizeOf)]
 pub struct Storage {
@@ -148,12 +147,12 @@ impl<'a> PrivateStorageHelpers for &'a Storage {
                                      new_value: Option<DOMString>){
         let global_root = self.global.root();
         let global_ref = global_root.r();
+        let main_script_chan = global_ref.as_window().main_thread_script_chan();
         let script_chan = global_ref.script_chan();
         let trusted_storage = Trusted::new(global_ref.get_cx(), self,
                                            script_chan.clone());
-        script_chan.send(ScriptMsg::MainThreadRunnableMsg(
+        main_script_chan.send(MainThreadScriptMsg::MainThreadRunnableMsg(
-            box StorageEventRunnable::new(trusted_storage, key,
+            box StorageEventRunnable::new(trusted_storage, key, old_value, new_value))).unwrap();
-                                          old_value, new_value))).unwrap();
     }
 }
 

components/script/dom/websocket.rs

@@ -22,8 +22,7 @@ use dom::closeevent::CloseEvent;
 use dom::event::{Event, EventBubbles, EventCancelable, EventHelpers};
 use dom::eventtarget::{EventTarget, EventTargetHelpers, EventTargetTypeId};
 use dom::messageevent::MessageEvent;
-use script_task::Runnable;
+use script_task::{Runnable, CommonScriptMsg};
-use script_task::ScriptMsg;
 
 use net_traits::hosts::replace_hosts;
 use util::str::DOMString;
@@ -179,7 +178,7 @@ impl WebSocket {
                     let task = box CloseTask {
                         addr: address,
                     };
-                    sender.send(ScriptMsg::RunnableMsg(task)).unwrap();
+                    sender.send(CommonScriptMsg::RunnableMsg(task)).unwrap();
                     return;
                 }
             };
@@ -189,7 +188,7 @@ impl WebSocket {
                 addr: address.clone(),
                 sender: ws_sender.clone(),
             };
-            sender.send(ScriptMsg::RunnableMsg(open_task)).unwrap();
+            sender.send(CommonScriptMsg::RunnableMsg(open_task)).unwrap();
 
             for message in receiver.incoming_messages() {
                 let message = match message {
@@ -205,7 +204,7 @@ impl WebSocket {
                         let task = box CloseTask {
                             addr: address,
                         };
-                        sender.send(ScriptMsg::RunnableMsg(task)).unwrap();
+                        sender.send(CommonScriptMsg::RunnableMsg(task)).unwrap();
                         break;
                     },
                     Err(_) => break,
@@ -214,7 +213,7 @@ impl WebSocket {
                     address: address.clone(),
                     message: message,
                 };
-                sender.send(ScriptMsg::RunnableMsg(message_task)).unwrap();
+                sender.send(CommonScriptMsg::RunnableMsg(message_task)).unwrap();
             }
         });
 

components/script/dom/window.rs

@@ -34,8 +34,8 @@ use dom::storage::Storage;
 use layout_interface::{ReflowGoal, ReflowQueryType, LayoutRPC, LayoutChan, Reflow, Msg};
 use layout_interface::{ContentBoxResponse, ContentBoxesResponse, ResolvedStyleResponse, ScriptReflow};
 use page::Page;
-use script_task::{TimerSource, ScriptChan, ScriptPort, NonWorkerScriptChan};
+use script_task::{TimerSource, ScriptChan, ScriptPort, MainThreadScriptMsg};
-use script_task::ScriptMsg;
+use script_task::{SendableMainThreadScriptChan, MainThreadScriptChan};
 use script_traits::ConstellationControlMsg;
 use timers::{IsInterval, TimerId, TimerManager, TimerCallback};
 use webdriver_handlers::jsval_to_webdriver;
@@ -110,7 +110,7 @@ pub enum ReflowReason {
 pub struct Window {
     eventtarget: EventTarget,
     #[ignore_heap_size_of = "trait objects are hard"]
-    script_chan: Box<ScriptChan+Send>,
+    script_chan: MainThreadScriptChan,
     #[ignore_heap_size_of = "channels are hard"]
     control_chan: Sender<ConstellationControlMsg>,
     console: MutNullableHeap<JS<Console>>,
@@ -236,6 +236,11 @@ impl Window {
         self.script_chan.clone()
     }
 
+    pub fn main_thread_script_chan(&self) -> &Sender<MainThreadScriptMsg> {
+        let MainThreadScriptChan(ref sender) = self.script_chan;
+        sender
+    }
+
     pub fn image_cache_chan(&self) -> ImageCacheChan {
         self.image_cache_chan.clone()
     }
@@ -261,7 +266,7 @@ impl Window {
 
     pub fn new_script_pair(&self) -> (Box<ScriptChan+Send>, Box<ScriptPort+Send>) {
         let (tx, rx) = channel();
-        (box NonWorkerScriptChan(tx), box rx)
+        (box SendableMainThreadScriptChan(tx), box rx)
     }
 
     pub fn image_cache_task<'a>(&'a self) -> &'a ImageCacheTask {
@@ -370,7 +375,7 @@ impl<'a> WindowMethods for &'a Window {
 
     // https://html.spec.whatwg.org/multipage/#dom-window-close
     fn Close(self) {
-        self.script_chan.send(ScriptMsg::ExitWindow(self.id.clone())).unwrap();
+        self.main_thread_script_chan().send(MainThreadScriptMsg::ExitWindow(self.id.clone())).unwrap();
     }
 
     // https://html.spec.whatwg.org/multipage/#dom-document-0
@@ -887,7 +892,8 @@ impl<'a> WindowHelpers for &'a Window {
 
     /// Commence a new URL load which will either replace this window or scroll to a fragment.
     fn load_url(self, url: Url) {
-        self.script_chan.send(ScriptMsg::Navigate(self.id, LoadData::new(url))).unwrap();
+        self.main_thread_script_chan().send(
+            MainThreadScriptMsg::Navigate(self.id, LoadData::new(url))).unwrap();
     }
 
     fn handle_fire_timer(self, timer_id: TimerId) {
@@ -1064,7 +1070,7 @@ impl<'a> WindowHelpers for &'a Window {
 impl Window {
     pub fn new(runtime: Rc<Runtime>,
                page: Rc<Page>,
-               script_chan: Box<ScriptChan+Send>,
+               script_chan: MainThreadScriptChan,
                image_cache_chan: ImageCacheChan,
                control_chan: Sender<ConstellationControlMsg>,
                compositor: ScriptListener,

components/script/dom/worker.rs

@@ -15,23 +15,22 @@ use dom::bindings::trace::JSTraceable;
 use dom::bindings::utils::{Reflectable, reflect_dom_object};
 use dom::bindings::js::Root;
 use dom::window::WindowHelpers;
-use dom::dedicatedworkerglobalscope::DedicatedWorkerGlobalScope;
+use dom::dedicatedworkerglobalscope::{DedicatedWorkerGlobalScope, WorkerScriptMsg};
 use dom::errorevent::ErrorEvent;
 use dom::event::{Event, EventBubbles, EventCancelable, EventHelpers};
 use dom::eventtarget::{EventTarget, EventTargetHelpers, EventTargetTypeId};
 use dom::messageevent::MessageEvent;
 use dom::workerglobalscope::WorkerGlobalScopeInit;
-use script_task::{ScriptChan, ScriptMsg, Runnable};
 
 use devtools_traits::{DevtoolsPageInfo, ScriptToDevtoolsControlMsg};
-
+use script_task::{ScriptChan, Runnable};
-use util::str::DOMString;
 
 use ipc_channel::ipc;
 use js::jsapi::{JSContext, HandleValue, RootedValue};
 use js::jsapi::{JSAutoRequest, JSAutoCompartment};
 use js::jsval::UndefinedValue;
 use url::UrlParser;
+use util::str::DOMString;
 
 use std::borrow::ToOwned;
 use std::sync::mpsc::{channel, Sender};
@@ -47,11 +46,13 @@ pub struct Worker {
     #[ignore_heap_size_of = "Defined in std"]
     /// Sender to the Receiver associated with the DedicatedWorkerGlobalScope
     /// this Worker created.
-    sender: Sender<(TrustedWorkerAddress, ScriptMsg)>,
+    sender: Sender<(TrustedWorkerAddress, WorkerScriptMsg)>,
 }
 
 impl Worker {
-    fn new_inherited(global: GlobalRef, sender: Sender<(TrustedWorkerAddress, ScriptMsg)>) -> Worker {
+    fn new_inherited(global: GlobalRef,
+                     sender: Sender<(TrustedWorkerAddress, WorkerScriptMsg)>)
+                     -> Worker {
         Worker {
             eventtarget: EventTarget::new_inherited(EventTargetTypeId::Worker),
             global: GlobalField::from_rooted(&global),
@@ -59,7 +60,9 @@ impl Worker {
         }
     }
 
-    pub fn new(global: GlobalRef, sender: Sender<(TrustedWorkerAddress, ScriptMsg)>) -> Root<Worker> {
+    pub fn new(global: GlobalRef,
+               sender: Sender<(TrustedWorkerAddress, WorkerScriptMsg)>)
+               -> Root<Worker> {
         reflect_dom_object(box Worker::new_inherited(global, sender),
                            global,
                            WorkerBinding::Wrap)
@@ -157,7 +160,7 @@ impl<'a> WorkerMethods for &'a Worker {
     fn PostMessage(self, cx: *mut JSContext, message: HandleValue) -> ErrorResult {
         let data = try!(StructuredCloneData::write(cx, message));
         let address = Trusted::new(cx, self, self.global.root().r().script_chan().clone());
-        self.sender.send((address, ScriptMsg::DOMMessage(data))).unwrap();
+        self.sender.send((address, WorkerScriptMsg::DOMMessage(data))).unwrap();
         Ok(())
     }
 

components/script/dom/workerglobalscope.rs

@@ -17,7 +17,7 @@ use dom::eventtarget::{EventTarget, EventTargetTypeId};
 use dom::workerlocation::WorkerLocation;
 use dom::workernavigator::WorkerNavigator;
 use dom::window::{base64_atob, base64_btoa};
-use script_task::{ScriptChan, TimerSource, ScriptPort, ScriptMsg};
+use script_task::{CommonScriptMsg, ScriptChan, TimerSource, ScriptPort};
 use timers::{IsInterval, TimerId, TimerManager, TimerCallback};
 
 use devtools_traits::{ScriptToDevtoolsControlMsg, DevtoolScriptControlMsg};
@@ -291,7 +291,7 @@ pub trait WorkerGlobalScopeHelpers {
     fn script_chan(self) -> Box<ScriptChan+Send>;
     fn pipeline(self) -> PipelineId;
     fn new_script_pair(self) -> (Box<ScriptChan+Send>, Box<ScriptPort+Send>);
-    fn process_event(self, msg: ScriptMsg);
+    fn process_event(self, msg: CommonScriptMsg);
     fn get_cx(self) -> *mut JSContext;
     fn set_devtools_wants_updates(self, value: bool);
 }
@@ -338,7 +338,7 @@ impl<'a> WorkerGlobalScopeHelpers for &'a WorkerGlobalScope {
         }
     }
 
-    fn process_event(self, msg: ScriptMsg) {
+    fn process_event(self, msg: CommonScriptMsg) {
         let dedicated =
             DedicatedWorkerGlobalScopeCast::to_ref(self);
         match dedicated {

components/script/dom/xmlhttprequest.rs

@@ -28,7 +28,7 @@ use dom::xmlhttprequesteventtarget::XMLHttpRequestEventTarget;
 use dom::xmlhttprequesteventtarget::XMLHttpRequestEventTargetTypeId;
 use dom::xmlhttprequestupload::XMLHttpRequestUpload;
 use network_listener::{NetworkListener, PreInvoke};
-use script_task::{ScriptChan, ScriptMsg, Runnable, ScriptPort};
+use script_task::{ScriptChan, Runnable, ScriptPort, CommonScriptMsg};
 
 use encoding::all::UTF_8;
 use encoding::label::encoding_from_whatwg_label;
@@ -1013,7 +1013,7 @@ impl<'a> PrivateXMLHttpRequestHelpers for &'a XMLHttpRequest {
             sleep_ms(duration_ms);
             match cancel_rx.try_recv() {
                 Err(TryRecvError::Empty) => {
-                    timeout_target.send(ScriptMsg::RunnableMsg(box XHRTimeout {
+                    timeout_target.send(CommonScriptMsg::RunnableMsg(box XHRTimeout {
                         xhr: xhr,
                         gen_id: gen_id,
                     })).unwrap();

components/script/network_listener.rs

@@ -2,7 +2,7 @@
  * 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 script_task::{ScriptChan, ScriptMsg, Runnable};
+use script_task::{ScriptChan, Runnable, CommonScriptMsg};
 use net_traits::{AsyncResponseListener, ResponseAction};
 use std::sync::{Arc, Mutex};
 
@@ -15,7 +15,7 @@ pub struct NetworkListener<T: AsyncResponseListener + PreInvoke + Send + 'static
 
 impl<T: AsyncResponseListener + PreInvoke + Send + 'static> NetworkListener<T> {
     pub fn notify(&self, action: ResponseAction) {
-        if let Err(err) = self.script_chan.send(ScriptMsg::RunnableMsg(box ListenerRunnable {
+        if let Err(err) = self.script_chan.send(CommonScriptMsg::RunnableMsg(box ListenerRunnable {
             context: self.context.clone(),
             action: action,
         })) {

components/script/script_task.rs

@@ -30,7 +30,6 @@ use dom::bindings::global::GlobalRef;
 use dom::bindings::js::{JS, RootCollection, trace_roots};
 use dom::bindings::js::{RootCollectionPtr, Root, RootedReference};
 use dom::bindings::refcounted::{LiveDOMReferences, Trusted, TrustedReference, trace_refcounted_objects};
-use dom::bindings::structuredclone::StructuredCloneData;
 use dom::bindings::trace::{JSTraceable, trace_traceables, RootedVec};
 use dom::bindings::utils::{WRAP_CALLBACKS, DOM_CALLBACKS};
 use dom::document::{Document, IsHTMLDocument, DocumentHelpers, DocumentProgressHandler,
@@ -179,45 +178,47 @@ pub trait MainThreadRunnable {
     fn handler(self: Box<Self>, script_task: &ScriptTask);
 }
 
-/// Messages used to control script event loops, such as ScriptTask and
+/// Common messages used to control the event loops in both the script and the worker
-/// DedicatedWorkerGlobalScope.
+pub enum CommonScriptMsg {
-pub enum ScriptMsg {
+    /// Requests that the script task measure its memory usage. The results are sent back via the
-    /// Begins a content-initiated load on the specified pipeline (only
+    /// supplied channel.
-    /// dispatched to ScriptTask).
+    CollectReports(ReportsChan),
-    Navigate(PipelineId, LoadData),
     /// Fires a JavaScript timeout
     /// TimerSource must be FromWindow when dispatched to ScriptTask and
     /// must be FromWorker when dispatched to a DedicatedGlobalWorkerScope
     FireTimer(TimerSource, TimerId),
+    /// A DOM object's last pinned reference was removed (dispatched to all tasks).
+    RefcountCleanup(TrustedReference),
+    /// Generic message that encapsulates event handling.
+    RunnableMsg(Box<Runnable+Send>),
+}
+
+/// Messages used to control the script event loop
+pub enum MainThreadScriptMsg {
+    /// Common variants associated with the script messages
+    Common(CommonScriptMsg),
+    /// Notify a document that all pending loads are complete.
+    DocumentLoadsComplete(PipelineId),
     /// Notifies the script that a window associated with a particular pipeline
     /// should be closed (only dispatched to ScriptTask).
     ExitWindow(PipelineId),
-    /// Message sent through Worker.postMessage (only dispatched to
-    /// DedicatedWorkerGlobalScope).
-    DOMMessage(StructuredCloneData),
-    /// Generic message that encapsulates event handling.
-    RunnableMsg(Box<Runnable+Send>),
     /// Generic message for running tasks in the ScriptTask
     MainThreadRunnableMsg(Box<MainThreadRunnable+Send>),
-    /// A DOM object's last pinned reference was removed (dispatched to all tasks).
+    /// Begins a content-initiated load on the specified pipeline (only
-    RefcountCleanup(TrustedReference),
+    /// dispatched to ScriptTask).
-    /// Notify a document that all pending loads are complete.
+    Navigate(PipelineId, LoadData),
-    DocumentLoadsComplete(PipelineId),
-    /// Requests that the script task measure its memory usage. The results are sent back via the
-    /// supplied channel.
-    CollectReports(ReportsChan),
 }
 
 /// A cloneable interface for communicating with an event loop.
 pub trait ScriptChan {
     /// Send a message to the associated event loop.
-    fn send(&self, msg: ScriptMsg) -> Result<(), ()>;
+    fn send(&self, msg: CommonScriptMsg) -> Result<(), ()>;
     /// Clone this handle.
     fn clone(&self) -> Box<ScriptChan+Send>;
 }
 
-impl OpaqueSender<ScriptMsg> for Box<ScriptChan+Send> {
+impl OpaqueSender<CommonScriptMsg> for Box<ScriptChan+Send> {
-    fn send(&self, msg: ScriptMsg) {
+    fn send(&self, msg: CommonScriptMsg) {
         ScriptChan::send(&**self, msg).unwrap();
     }
 }
@@ -226,42 +227,84 @@ impl OpaqueSender<ScriptMsg> for Box<ScriptChan+Send> {
 /// APIs that need to abstract over multiple kinds of event loops (worker/main thread) with
 /// different Receiver interfaces.
 pub trait ScriptPort {
-    fn recv(&self) -> ScriptMsg;
+    fn recv(&self) -> CommonScriptMsg;
 }
 
-impl ScriptPort for Receiver<ScriptMsg> {
+impl ScriptPort for Receiver<CommonScriptMsg> {
-    fn recv(&self) -> ScriptMsg {
+    fn recv(&self) -> CommonScriptMsg {
         self.recv().unwrap()
     }
 }
 
-impl ScriptPort for Receiver<(TrustedWorkerAddress, ScriptMsg)> {
+impl ScriptPort for Receiver<MainThreadScriptMsg> {
-    fn recv(&self) -> ScriptMsg {
+    fn recv(&self) -> CommonScriptMsg {
+        match self.recv().unwrap() {
+            MainThreadScriptMsg::Common(script_msg) => script_msg,
+            _ => panic!("unexpected main thread event message!")
+        }
+    }
+}
+
+impl ScriptPort for Receiver<(TrustedWorkerAddress, CommonScriptMsg)> {
+    fn recv(&self) -> CommonScriptMsg {
         self.recv().unwrap().1
     }
 }
 
-/// Encapsulates internal communication within the script task.
+impl ScriptPort for Receiver<(TrustedWorkerAddress, MainThreadScriptMsg)> {
-#[derive(JSTraceable)]
+    fn recv(&self) -> CommonScriptMsg {
-pub struct NonWorkerScriptChan(pub Sender<ScriptMsg>);
+        match self.recv().unwrap().1 {
+            MainThreadScriptMsg::Common(script_msg) => script_msg,
+            _ => panic!("unexpected main thread event message!")
+        }
+    }
+}
 
-impl ScriptChan for NonWorkerScriptChan {
+/// Encapsulates internal communication of shared messages within the script task.
-    fn send(&self, msg: ScriptMsg) -> Result<(), ()> {
+#[derive(JSTraceable)]
-        let NonWorkerScriptChan(ref chan) = *self;
+pub struct SendableMainThreadScriptChan(pub Sender<CommonScriptMsg>);
+
+impl ScriptChan for SendableMainThreadScriptChan {
+    fn send(&self, msg: CommonScriptMsg) -> Result<(), ()> {
+        let SendableMainThreadScriptChan(ref chan) = *self;
         return chan.send(msg).map_err(|_| ());
     }
 
     fn clone(&self) -> Box<ScriptChan+Send> {
-        let NonWorkerScriptChan(ref chan) = *self;
+        let SendableMainThreadScriptChan(ref chan) = *self;
-        box NonWorkerScriptChan((*chan).clone())
+        box SendableMainThreadScriptChan((*chan).clone())
     }
 }
 
-impl NonWorkerScriptChan {
+impl SendableMainThreadScriptChan {
     /// Creates a new script chan.
-    pub fn new() -> (Receiver<ScriptMsg>, Box<NonWorkerScriptChan>) {
+    pub fn new() -> (Receiver<CommonScriptMsg>, Box<SendableMainThreadScriptChan>) {
         let (chan, port) = channel();
-        (port, box NonWorkerScriptChan(chan))
+        (port, box SendableMainThreadScriptChan(chan))
+    }
+}
+
+/// Encapsulates internal communication of main thread messages within the script task.
+#[derive(JSTraceable)]
+pub struct MainThreadScriptChan(pub Sender<MainThreadScriptMsg>);
+
+impl ScriptChan for MainThreadScriptChan {
+    fn send(&self, msg: CommonScriptMsg) -> Result<(), ()> {
+        let MainThreadScriptChan(ref chan) = *self;
+        return chan.send(MainThreadScriptMsg::Common(msg)).map_err(|_| ());
+    }
+
+    fn clone(&self) -> Box<ScriptChan+Send> {
+        let MainThreadScriptChan(ref chan) = *self;
+        box MainThreadScriptChan((*chan).clone())
+    }
+}
+
+impl MainThreadScriptChan {
+    /// Creates a new script chan.
+    pub fn new() -> (Receiver<MainThreadScriptMsg>, Box<MainThreadScriptChan>) {
+        let (chan, port) = channel();
+        (port, box MainThreadScriptChan(chan))
     }
 }
 
@@ -302,10 +345,10 @@ pub struct ScriptTask {
     storage_task: StorageTask,
 
     /// The port on which the script task receives messages (load URL, exit, etc.)
-    port: Receiver<ScriptMsg>,
+    port: Receiver<MainThreadScriptMsg>,
     /// A channel to hand out to script task-based entities that need to be able to enqueue
     /// events in the event queue.
-    chan: NonWorkerScriptChan,
+    chan: MainThreadScriptChan,
 
     /// A channel to hand out to tasks that need to respond to a message from the script task.
     control_chan: Sender<ConstellationControlMsg>,
@@ -419,7 +462,7 @@ impl ScriptTaskFactory for ScriptTask {
         spawn_named_with_send_on_failure(format!("ScriptTask {:?}", id), task_state::SCRIPT, move || {
             let roots = RootCollection::new();
             let _stack_roots_tls = StackRootTLS::new(&roots);
-            let chan = NonWorkerScriptChan(script_chan);
+            let chan = MainThreadScriptChan(script_chan);
             let channel_for_reporter = chan.clone();
             let script_task = ScriptTask::new(compositor,
                                               script_port,
@@ -446,7 +489,7 @@ impl ScriptTaskFactory for ScriptTask {
             let reporter_name = format!("script-reporter-{}", id.0);
             mem_profiler_chan.run_with_memory_reporting(|| {
                 script_task.start();
-            }, reporter_name, channel_for_reporter, ScriptMsg::CollectReports);
+            }, reporter_name, channel_for_reporter, CommonScriptMsg::CollectReports);
 
             // This must always be the very last operation performed before the task completes
             failsafe.neuter();
@@ -526,19 +569,19 @@ impl ScriptTask {
         });
     }
 
-    pub fn process_event(msg: ScriptMsg) {
+    pub fn process_event(msg: CommonScriptMsg) {
         SCRIPT_TASK_ROOT.with(|root| {
             if let Some(script_task) = *root.borrow() {
                 let script_task = unsafe { &*script_task };
-                script_task.handle_msg_from_script(msg);
+                script_task.handle_msg_from_script(MainThreadScriptMsg::Common(msg));
             }
         });
     }
 
     /// Creates a new script task.
     pub fn new(compositor: ScriptListener,
-               port: Receiver<ScriptMsg>,
+               port: Receiver<MainThreadScriptMsg>,
-               chan: NonWorkerScriptChan,
+               chan: MainThreadScriptChan,
                control_chan: Sender<ConstellationControlMsg>,
                control_port: Receiver<ConstellationControlMsg>,
                constellation_chan: ConstellationChan,
@@ -672,7 +715,7 @@ impl ScriptTask {
 
         enum MixedMessage {
             FromConstellation(ConstellationControlMsg),
-            FromScript(ScriptMsg),
+            FromScript(MainThreadScriptMsg),
             FromDevtools(DevtoolScriptControlMsg),
             FromImageCache(ImageCacheResult),
         }
@@ -855,27 +898,27 @@ impl ScriptTask {
         }
     }
 
-    fn handle_msg_from_script(&self, msg: ScriptMsg) {
+    fn handle_msg_from_script(&self, msg: MainThreadScriptMsg) {
         match msg {
-            ScriptMsg::Navigate(id, load_data) =>
+            MainThreadScriptMsg::Navigate(id, load_data) =>
                 self.handle_navigate(id, None, load_data),
-            ScriptMsg::FireTimer(TimerSource::FromWindow(id), timer_id) =>
+            MainThreadScriptMsg::ExitWindow(id) =>
-                self.handle_fire_timer_msg(id, timer_id),
-            ScriptMsg::FireTimer(TimerSource::FromWorker, _) =>
-                panic!("Worker timeouts must not be sent to script task"),
-            ScriptMsg::ExitWindow(id) =>
                 self.handle_exit_window_msg(id),
-            ScriptMsg::DOMMessage(..) =>
+            MainThreadScriptMsg::MainThreadRunnableMsg(runnable) =>
-                panic!("unexpected message"),
-            ScriptMsg::RunnableMsg(runnable) =>
-                runnable.handler(),
-            ScriptMsg::MainThreadRunnableMsg(runnable) =>
                 runnable.handler(self),
-            ScriptMsg::RefcountCleanup(addr) =>
+            MainThreadScriptMsg::DocumentLoadsComplete(id) =>
-                LiveDOMReferences::cleanup(addr),
-            ScriptMsg::DocumentLoadsComplete(id) =>
                 self.handle_loads_complete(id),
-            ScriptMsg::CollectReports(reports_chan) =>
+            MainThreadScriptMsg::Common(
+                CommonScriptMsg::FireTimer(TimerSource::FromWindow(id), timer_id)) =>
+                self.handle_fire_timer_msg(id, timer_id),
+            MainThreadScriptMsg::Common(
+                CommonScriptMsg::FireTimer(TimerSource::FromWorker, _)) =>
+                panic!("Worker timeouts must not be sent to script task"),
+            MainThreadScriptMsg::Common(CommonScriptMsg::RunnableMsg(runnable)) =>
+                runnable.handler(),
+            MainThreadScriptMsg::Common(CommonScriptMsg::RefcountCleanup(addr)) =>
+                LiveDOMReferences::cleanup(addr),
+            MainThreadScriptMsg::Common(CommonScriptMsg::CollectReports(reports_chan)) =>
                 self.collect_reports(reports_chan),
         }
     }
@@ -1085,7 +1128,7 @@ impl ScriptTask {
         // https://html.spec.whatwg.org/multipage/#the-end step 7
         let addr: Trusted<Document> = Trusted::new(self.get_cx(), doc, self.chan.clone());
         let handler = box DocumentProgressHandler::new(addr.clone(), DocumentProgressTask::Load);
-        self.chan.send(ScriptMsg::RunnableMsg(handler)).unwrap();
+        self.chan.send(CommonScriptMsg::RunnableMsg(handler)).unwrap();
 
         let ConstellationChan(ref chan) = self.constellation_chan;
         chan.send(ConstellationMsg::LoadComplete(pipeline)).unwrap();
@@ -1455,11 +1498,12 @@ impl ScriptTask {
             PageToRemove::Child(incomplete.pipeline_id)
         };
         let mut page_remover = AutoPageRemover::new(self, page_to_remove);
+        let MainThreadScriptChan(ref sender) = self.chan;
 
         // Create the window and document objects.
         let window = Window::new(self.js_runtime.clone(),
                                  page.clone(),
-                                 self.chan.clone(),
+                                 MainThreadScriptChan(sender.clone()),
                                  self.image_cache_channel.clone(),
                                  self.control_chan.clone(),
                                  self.compositor.borrow_mut().dup(),
@@ -1485,9 +1529,12 @@ impl ScriptTask {
             _ => None
         };
 
-        let notifier_data = NotifierData {
+        let notifier_data =  {
-            script_chan: self.chan.clone(),
+            let MainThreadScriptChan(ref sender) = self.chan;
-            pipeline: page.pipeline(),
+            NotifierData {
+                script_chan: sender.clone(),
+                pipeline: page.pipeline(),
+            }
         };
         let loader = DocumentLoader::new_with_task(self.resource_task.clone(),
                                                    Some(notifier_data),
@@ -1822,7 +1869,7 @@ impl ScriptTask {
         // https://html.spec.whatwg.org/multipage/#the-end step 4
         let addr: Trusted<Document> = Trusted::new(self.get_cx(), document.r(), self.chan.clone());
         let handler = box DocumentProgressHandler::new(addr, DocumentProgressTask::DOMContentLoaded);
-        self.chan.send(ScriptMsg::RunnableMsg(handler)).unwrap();
+        self.chan.send(CommonScriptMsg::RunnableMsg(handler)).unwrap();
 
         window.r().set_fragment_name(final_url.fragment.clone());
 

components/script/timers.rs

@@ -7,10 +7,9 @@ use dom::bindings::callback::ExceptionHandling::Report;
 use dom::bindings::codegen::Bindings::FunctionBinding::Function;
 use dom::bindings::global::global_object_for_js_object;
 use dom::bindings::utils::Reflectable;
-
 use dom::window::ScriptHelpers;
 
-use script_task::{ScriptChan, ScriptMsg, TimerSource};
+use script_task::{ScriptChan, TimerSource, CommonScriptMsg};
 use horribly_inefficient_timers;
 
 use util::mem::HeapSizeOf;
@@ -149,7 +148,7 @@ impl TimerManager {
         let handle = self.next_timer_handle.get();
         self.next_timer_handle.set(handle + 1);
 
-        // Spawn a new timer task; it will dispatch the `ScriptMsg::FireTimer`
+        // Spawn a new timer task; it will dispatch the `CommonScriptMsg::FireTimer`
         // to the relevant script handler that will deal with it.
         let (control_chan, control_port) = channel();
         let spawn_name = match source {
@@ -177,7 +176,7 @@ impl TimerManager {
 
                 if id == timeout_handle.id() {
                     timeout_port.recv().unwrap();
-                    if script_chan.send(ScriptMsg::FireTimer(source, TimerId(handle))).is_err() {
+                    if script_chan.send(CommonScriptMsg::FireTimer(source, TimerId(handle))).is_err() {
                         break;
                     }