add a control chan to workers, use to signal shutdown

components/script/dom/abstractworkerglobalscope.rs

@@ -82,12 +82,15 @@ impl ScriptPort for Receiver<DedicatedWorkerScriptMsg> {
 
 pub trait WorkerEventLoopMethods {
     type WorkerMsg: QueuedTaskConversion + Send;
+    type ControlMsg;
     type Event;
     fn task_queue(&self) -> &TaskQueue<Self::WorkerMsg>;
-    fn handle_event(&self, event: Self::Event);
+    fn handle_event(&self, event: Self::Event) -> bool;
     fn handle_worker_post_event(&self, worker: &TrustedWorkerAddress) -> Option<AutoWorkerReset>;
+    fn from_control_msg(&self, msg: Self::ControlMsg) -> Self::Event;
     fn from_worker_msg(&self, msg: Self::WorkerMsg) -> Self::Event;
     fn from_devtools_msg(&self, msg: DevtoolScriptControlMsg) -> Self::Event;
+    fn control_receiver(&self) -> &Receiver<Self::ControlMsg>;
 }
 
 // https://html.spec.whatwg.org/multipage/#worker-event-loop
@@ -108,6 +111,7 @@ pub fn run_worker_event_loop<T, WorkerMsg, Event>(
     };
     let task_queue = worker_scope.task_queue();
     let event = select! {
+        recv(worker_scope.control_receiver()) -> msg => worker_scope.from_control_msg(msg.unwrap()),
         recv(task_queue.select()) -> msg => {
             task_queue.take_tasks(msg.unwrap());
             worker_scope.from_worker_msg(task_queue.recv().unwrap())
@@ -136,7 +140,10 @@ pub fn run_worker_event_loop<T, WorkerMsg, Event>(
     }
     // Step 3
     for event in sequential {
-        worker_scope.handle_event(event);
+        if !worker_scope.handle_event(event) {
+            // Shutdown
+            return;
+        }
         // Step 6
         let _ar = match worker {
             Some(worker) => worker_scope.handle_worker_post_event(worker),

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 {
@@ -183,32 +190,45 @@ 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> {
         let ar = AutoWorkerReset::new(&self, worker.clone());
         Some(ar)
     }
 
+    fn from_control_msg(&self, msg: DedicatedWorkerControlMsg) -> MixedMessage {
+        MixedMessage::FromControl(msg)
+    }
+
     fn from_worker_msg(&self, msg: DedicatedWorkerScriptMsg) -> MixedMessage {
         MixedMessage::FromWorker(msg)
     }
 
     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

components/script/dom/globalscope.rs

@@ -26,7 +26,9 @@ use crate::dom::bindings::weakref::{DOMTracker, WeakRef};
 use crate::dom::blob::Blob;
 use crate::dom::broadcastchannel::BroadcastChannel;
 use crate::dom::crypto::Crypto;
-use crate::dom::dedicatedworkerglobalscope::DedicatedWorkerGlobalScope;
+use crate::dom::dedicatedworkerglobalscope::{
+    DedicatedWorkerControlMsg, DedicatedWorkerGlobalScope,
+};
 use crate::dom::errorevent::ErrorEvent;
 use crate::dom::event::{Event, EventBubbles, EventCancelable, EventStatus};
 use crate::dom::eventsource::EventSource;
@@ -65,6 +67,7 @@ use crate::task_source::TaskSourceName;
 use crate::timers::{IsInterval, OneshotTimerCallback, OneshotTimerHandle};
 use crate::timers::{OneshotTimers, TimerCallback};
 use content_security_policy::CspList;
+use crossbeam_channel::Sender;
 use devtools_traits::{PageError, ScriptToDevtoolsControlMsg};
 use dom_struct::dom_struct;
 use embedder_traits::EmbedderMsg;
@@ -118,8 +121,13 @@ use uuid::Uuid;
 
 #[derive(JSTraceable)]
 pub struct AutoCloseWorker {
+    /// https://html.spec.whatwg.org/multipage/#dom-workerglobalscope-closing
     closing: Arc<AtomicBool>,
+    /// A handle to join on the worker thread.
     join_handle: Option<JoinHandle<()>>,
+    /// A sender of control messages,
+    /// currently only used to signal shutdown.
+    control_sender: Sender<DedicatedWorkerControlMsg>,
 }
 
 impl Drop for AutoCloseWorker {
@@ -128,13 +136,25 @@ impl Drop for AutoCloseWorker {
         // Step 1.
         self.closing.store(true, Ordering::SeqCst);
 
+        if self
+            .control_sender
+            .send(DedicatedWorkerControlMsg::Exit)
+            .is_err()
+        {
+            warn!("Couldn't send an exit message to a dedicated worker.");
+        }
+
         // TODO: step 2 and 3.
         // Step 4 is unnecessary since we don't use actual ports for dedicated workers.
-        self.join_handle
+        if self
+            .join_handle
             .take()
             .expect("No handle to join on worker.")
             .join()
-            .expect("Couldn't join on worker thread.");
+            .is_err()
+        {
+            warn!("Failed to join on dedicated worker thread.");
+        }
     }
 }
 
@@ -1808,12 +1828,18 @@ impl GlobalScope {
         &self.permission_state_invocation_results
     }
 
-    pub fn track_worker(&self, closing: Arc<AtomicBool>, join_handle: JoinHandle<()>) {
+    pub fn track_worker(
+        &self,
+        closing: Arc<AtomicBool>,
+        join_handle: JoinHandle<()>,
+        control_sender: Sender<DedicatedWorkerControlMsg>,
+    ) {
         self.list_auto_close_worker
             .borrow_mut()
             .push(AutoCloseWorker {
                 closing,
                 join_handle: Some(join_handle),
+                control_sender: control_sender,
             });
     }