add a control chan to workers, use to signal shutdown

components/script/dom/dedicatedworkerglobalscope.rs

@@ -86,6 +86,12 @@ impl<'a> Drop for AutoWorkerReset<'a> {
     }
 }
 
+/// Messages sent from the owning global.
+pub enum DedicatedWorkerControlMsg {
+    /// Shutdown the worker.
+    Exit,
+}
+
 pub enum DedicatedWorkerScriptMsg {
     /// Standard message from a worker.
     CommonWorker(TrustedWorkerAddress, WorkerScriptMsg),
@@ -96,6 +102,7 @@ pub enum DedicatedWorkerScriptMsg {
 pub enum MixedMessage {
     FromWorker(DedicatedWorkerScriptMsg),
     FromDevtools(DevtoolScriptControlMsg),
+    FromControl(DedicatedWorkerControlMsg),
 }
 
 impl QueuedTaskConversion for DedicatedWorkerScriptMsg {
@@ -183,18 +190,23 @@ pub struct DedicatedWorkerGlobalScope {
     #[ignore_malloc_size_of = "Arc"]
     image_cache: Arc<dyn ImageCache>,
     browsing_context: Option<BrowsingContextId>,
+    /// A receiver of control messages,
+    /// currently only used to signal shutdown.
+    #[ignore_malloc_size_of = "Channels are hard"]
+    control_receiver: Receiver<DedicatedWorkerControlMsg>,
 }
 
 impl WorkerEventLoopMethods for DedicatedWorkerGlobalScope {
     type WorkerMsg = DedicatedWorkerScriptMsg;
+    type ControlMsg = DedicatedWorkerControlMsg;
     type Event = MixedMessage;
 
     fn task_queue(&self) -> &TaskQueue<DedicatedWorkerScriptMsg> {
         &self.task_queue
     }
 
-    fn handle_event(&self, event: MixedMessage) {
-        self.handle_mixed_message(event);
+    fn handle_event(&self, event: MixedMessage) -> bool {
+        self.handle_mixed_message(event)
     }
 
     fn handle_worker_post_event(&self, worker: &TrustedWorkerAddress) -> Option<AutoWorkerReset> {
@@ -202,6 +214,10 @@ impl WorkerEventLoopMethods for DedicatedWorkerGlobalScope {
         Some(ar)
     }
 
+    fn from_control_msg(&self, msg: DedicatedWorkerControlMsg) -> MixedMessage {
+        MixedMessage::FromControl(msg)
+    }
+
     fn from_worker_msg(&self, msg: DedicatedWorkerScriptMsg) -> MixedMessage {
         MixedMessage::FromWorker(msg)
     }
@@ -209,6 +225,10 @@ impl WorkerEventLoopMethods for DedicatedWorkerGlobalScope {
     fn from_devtools_msg(&self, msg: DevtoolScriptControlMsg) -> MixedMessage {
         MixedMessage::FromDevtools(msg)
     }
+
+    fn control_receiver(&self) -> &Receiver<DedicatedWorkerControlMsg> {
+        &self.control_receiver
+    }
 }
 
 impl DedicatedWorkerGlobalScope {
@@ -226,6 +246,7 @@ impl DedicatedWorkerGlobalScope {
         image_cache: Arc<dyn ImageCache>,
         browsing_context: Option<BrowsingContextId>,
         gpu_id_hub: Arc<Mutex<Identities>>,
+        control_receiver: Receiver<DedicatedWorkerControlMsg>,
     ) -> DedicatedWorkerGlobalScope {
         DedicatedWorkerGlobalScope {
             workerglobalscope: WorkerGlobalScope::new_inherited(
@@ -244,6 +265,7 @@ impl DedicatedWorkerGlobalScope {
             worker: DomRefCell::new(None),
             image_cache: image_cache,
             browsing_context,
+            control_receiver,
         }
     }
 
@@ -262,6 +284,7 @@ impl DedicatedWorkerGlobalScope {
         image_cache: Arc<dyn ImageCache>,
         browsing_context: Option<BrowsingContextId>,
         gpu_id_hub: Arc<Mutex<Identities>>,
+        control_receiver: Receiver<DedicatedWorkerControlMsg>,
     ) -> DomRoot<DedicatedWorkerGlobalScope> {
         let cx = runtime.cx();
         let scope = Box::new(DedicatedWorkerGlobalScope::new_inherited(
@@ -278,6 +301,7 @@ impl DedicatedWorkerGlobalScope {
             image_cache,
             browsing_context,
             gpu_id_hub,
+            control_receiver,
         ));
         unsafe { DedicatedWorkerGlobalScopeBinding::Wrap(SafeJSContext::from_ptr(cx), scope) }
     }
@@ -299,6 +323,7 @@ impl DedicatedWorkerGlobalScope {
         image_cache: Arc<dyn ImageCache>,
         browsing_context: Option<BrowsingContextId>,
         gpu_id_hub: Arc<Mutex<Identities>>,
+        control_receiver: Receiver<DedicatedWorkerControlMsg>,
     ) -> JoinHandle<()> {
         let serialized_worker_url = worker_url.to_string();
         let name = format!("WebWorker for {}", serialized_worker_url);
@@ -370,6 +395,7 @@ impl DedicatedWorkerGlobalScope {
                     image_cache,
                     browsing_context,
                     gpu_id_hub,
+                    control_receiver,
                 );
                 // FIXME(njn): workers currently don't have a unique ID suitable for using in reporter
                 // registration (#6631), so we instead use a random number and cross our fingers.
@@ -485,7 +511,7 @@ impl DedicatedWorkerGlobalScope {
         }
     }
 
-    fn handle_mixed_message(&self, msg: MixedMessage) {
+    fn handle_mixed_message(&self, msg: MixedMessage) -> bool {
         // FIXME(#26324): `self.worker` is None in devtools messages.
         match msg {
             MixedMessage::FromDevtools(msg) => match msg {
@@ -505,7 +531,11 @@ impl DedicatedWorkerGlobalScope {
                 self.handle_script_event(msg);
             },
             MixedMessage::FromWorker(DedicatedWorkerScriptMsg::WakeUp) => {},
+            MixedMessage::FromControl(DedicatedWorkerControlMsg::Exit) => {
+                return false;
+            },
         }
+        true
     }
 
     // https://html.spec.whatwg.org/multipage/#runtime-script-errors-2