script: Reduce ScriptThread TLS usage (#38875)

We store a pointer to the ScriptThread singleton for a thread in
thread-local storage. While we don't have yet have profiles pointing to
this TLS access as a hot spot, we can remove a potential performance
footgun without a lot of effort by passing around small pieces of data
that we otherwise need to fetch from the ScriptThread.

Testing: Existing WPT is sufficient
Fixes: part of #37969

---------

Signed-off-by: Josh Matthews <josh@joshmatthews.net>

components/script/dom/abstractworkerglobalscope.rs

@@ -2,6 +2,8 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 
+use std::collections::HashSet;
+
 use crossbeam_channel::{Receiver, select};
 use devtools_traits::DevtoolScriptControlMsg;
 
@@ -53,7 +55,7 @@ pub(crate) fn run_worker_event_loop<T, WorkerMsg, Event>(
     let event = select! {
         recv(worker_scope.control_receiver()) -> msg => T::from_control_msg(msg.unwrap()),
         recv(task_queue.select()) -> msg => {
-            task_queue.take_tasks(msg.unwrap());
+            task_queue.take_tasks(msg.unwrap(), &HashSet::new());
             T::from_worker_msg(task_queue.recv().unwrap())
         },
         recv(devtools_receiver) -> msg => T::from_devtools_msg(msg.unwrap()),
@@ -72,7 +74,7 @@ pub(crate) fn run_worker_event_loop<T, WorkerMsg, Event>(
     while !scope.is_closing() {
         // Batch all events that are ready.
         // The task queue will throttle non-priority tasks if necessary.
-        match task_queue.take_tasks_and_recv() {
+        match task_queue.take_tasks_and_recv(&HashSet::new()) {
             Err(_) => match devtools_receiver.try_recv() {
                 Ok(message) => sequential.push(T::from_devtools_msg(message)),
                 Err(_) => break,

components/script/dom/bindings/constructor.rs

@@ -52,7 +52,6 @@ use crate::dom::globalscope::GlobalScope;
 use crate::dom::htmlelement::HTMLElement;
 use crate::dom::window::Window;
 use crate::script_runtime::{CanGc, JSContext, JSContext as SafeJSContext};
-use crate::script_thread::ScriptThread;
 
 /// <https://html.spec.whatwg.org/multipage/#htmlconstructor>
 fn html_constructor(
@@ -391,14 +390,6 @@ fn get_constructor_object_from_local_name(
     true
 }
 
-pub(crate) fn pop_current_element_queue(can_gc: CanGc) {
-    ScriptThread::pop_current_element_queue(can_gc);
-}
-
-pub(crate) fn push_new_element_queue() {
-    ScriptThread::push_new_element_queue();
-}
-
 pub(crate) fn call_html_constructor<T: DerivedFrom<Element> + DomObject>(
     cx: JSContext,
     args: &CallArgs,

components/script/dom/bindings/utils.rs

@@ -19,9 +19,7 @@ use script_bindings::settings_stack::StackEntry;
 
 use crate::DomTypes;
 use crate::dom::bindings::codegen::{InterfaceObjectMap, PrototypeList};
-use crate::dom::bindings::constructor::{
+use crate::dom::bindings::constructor::call_html_constructor;
-    call_html_constructor, pop_current_element_queue, push_new_element_queue,
-};
 use crate::dom::bindings::conversions::DerivedFrom;
 use crate::dom::bindings::error::{Error, report_pending_exception, throw_dom_exception};
 use crate::dom::bindings::principals::PRINCIPALS_CALLBACKS;
@@ -33,6 +31,7 @@ use crate::dom::globalscope::GlobalScope;
 use crate::dom::windowproxy::WindowProxyHandler;
 use crate::realms::InRealm;
 use crate::script_runtime::{CanGc, JSContext as SafeJSContext};
+use crate::script_thread::ScriptThread;
 
 #[derive(JSTraceable, MallocSizeOf)]
 /// Static data associated with a global object.
@@ -185,10 +184,10 @@ impl DomHelpers<crate::DomTypeHolder> for crate::DomTypeHolder {
     }
 
     fn push_new_element_queue() {
-        push_new_element_queue()
+        ScriptThread::custom_element_reaction_stack().push_new_element_queue()
     }
     fn pop_current_element_queue(can_gc: CanGc) {
-        pop_current_element_queue(can_gc)
+        ScriptThread::custom_element_reaction_stack().pop_current_element_queue(can_gc)
     }
 
     fn reflect_dom_object<T, U>(obj: Box<T>, global: &U, can_gc: CanGc) -> DomRoot<T>

components/script/dom/customelementregistry.rs

@@ -1044,8 +1044,12 @@ enum BackupElementQueueFlag {
 }
 
 /// <https://html.spec.whatwg.org/multipage/#custom-element-reactions-stack>
+/// # Safety
+/// This can be shared inside an Rc because one of those Rc copies lives
+/// inside ScriptThread, so the GC can always reach this structure.
 #[derive(JSTraceable, MallocSizeOf)]
 #[cfg_attr(crown, crown::unrooted_must_root_lint::must_root)]
+#[cfg_attr(crown, crown::unrooted_must_root_lint::allow_unrooted_in_rc)]
 pub(crate) struct CustomElementReactionStack {
     stack: DomRefCell<Vec<ElementQueue>>,
     backup_queue: ElementQueue,

components/script/dom/document.rs

@@ -124,7 +124,7 @@ use crate::dom::cdatasection::CDATASection;
 use crate::dom::comment::Comment;
 use crate::dom::compositionevent::CompositionEvent;
 use crate::dom::cssstylesheet::CSSStyleSheet;
-use crate::dom::customelementregistry::CustomElementDefinition;
+use crate::dom::customelementregistry::{CustomElementDefinition, CustomElementReactionStack};
 use crate::dom::customevent::CustomEvent;
 use crate::dom::document_event_handler::DocumentEventHandler;
 use crate::dom::documentfragment::DocumentFragment;
@@ -565,6 +565,10 @@ pub(crate) struct Document {
     /// this `Document` will not perform any more rendering updates.
     #[no_trace]
     current_canvas_epoch: RefCell<Epoch>,
+
+    /// The global custom element reaction stack for this script thread.
+    #[conditional_malloc_size_of]
+    custom_element_reaction_stack: Rc<CustomElementReactionStack>,
 }
 
 #[allow(non_snake_case)]
@@ -3261,6 +3265,7 @@ impl Document {
         allow_declarative_shadow_roots: bool,
         inherited_insecure_requests_policy: Option<InsecureRequestsPolicy>,
         has_trustworthy_ancestor_origin: bool,
+        custom_element_reaction_stack: Rc<CustomElementReactionStack>,
     ) -> Document {
         let url = url.unwrap_or_else(|| ServoUrl::parse("about:blank").unwrap());
 
@@ -3434,6 +3439,7 @@ impl Document {
             resize_observer_started_observing_target: Cell::new(false),
             waiting_on_canvas_image_updates: Cell::new(false),
             current_canvas_epoch: RefCell::new(Epoch(0)),
+            custom_element_reaction_stack,
         }
     }
 
@@ -3536,6 +3542,7 @@ impl Document {
         allow_declarative_shadow_roots: bool,
         inherited_insecure_requests_policy: Option<InsecureRequestsPolicy>,
         has_trustworthy_ancestor_origin: bool,
+        custom_element_reaction_stack: Rc<CustomElementReactionStack>,
         can_gc: CanGc,
     ) -> DomRoot<Document> {
         Self::new_with_proto(
@@ -3557,6 +3564,7 @@ impl Document {
             allow_declarative_shadow_roots,
             inherited_insecure_requests_policy,
             has_trustworthy_ancestor_origin,
+            custom_element_reaction_stack,
             can_gc,
         )
     }
@@ -3581,6 +3589,7 @@ impl Document {
         allow_declarative_shadow_roots: bool,
         inherited_insecure_requests_policy: Option<InsecureRequestsPolicy>,
         has_trustworthy_ancestor_origin: bool,
+        custom_element_reaction_stack: Rc<CustomElementReactionStack>,
         can_gc: CanGc,
     ) -> DomRoot<Document> {
         let document = reflect_dom_object_with_proto(
@@ -3602,6 +3611,7 @@ impl Document {
                 allow_declarative_shadow_roots,
                 inherited_insecure_requests_policy,
                 has_trustworthy_ancestor_origin,
+                custom_element_reaction_stack,
             )),
             window,
             proto,
@@ -3736,6 +3746,7 @@ impl Document {
                     self.allow_declarative_shadow_roots(),
                     Some(self.insecure_requests_policy()),
                     self.has_trustworthy_ancestor_or_current_origin(),
+                    self.custom_element_reaction_stack.clone(),
                     can_gc,
                 );
                 new_doc
@@ -4413,6 +4424,10 @@ impl Document {
     pub(crate) fn highlighted_dom_node(&self) -> Option<DomRoot<Node>> {
         self.highlighted_dom_node.get()
     }
+
+    pub(crate) fn custom_element_reaction_stack(&self) -> Rc<CustomElementReactionStack> {
+        self.custom_element_reaction_stack.clone()
+    }
 }
 
 #[allow(non_snake_case)]
@@ -4444,6 +4459,7 @@ impl DocumentMethods<crate::DomTypeHolder> for Document {
             doc.allow_declarative_shadow_roots(),
             Some(doc.insecure_requests_policy()),
             doc.has_trustworthy_ancestor_or_current_origin(),
+            doc.custom_element_reaction_stack(),
             can_gc,
         ))
     }

components/script/dom/domimplementation.rs

@@ -117,6 +117,7 @@ impl DOMImplementationMethods<crate::DomTypeHolder> for DOMImplementation {
             loader,
             Some(self.document.insecure_requests_policy()),
             self.document.has_trustworthy_ancestor_or_current_origin(),
+            self.document.custom_element_reaction_stack(),
             can_gc,
         );
 
@@ -184,6 +185,7 @@ impl DOMImplementationMethods<crate::DomTypeHolder> for DOMImplementation {
             self.document.allow_declarative_shadow_roots(),
             Some(self.document.insecure_requests_policy()),
             self.document.has_trustworthy_ancestor_or_current_origin(),
+            self.document.custom_element_reaction_stack(),
             can_gc,
         );
 

components/script/dom/domparser.rs

@@ -104,6 +104,7 @@ impl DOMParserMethods<crate::DomTypeHolder> for DOMParser {
                     false,
                     Some(doc.insecure_requests_policy()),
                     doc.has_trustworthy_ancestor_or_current_origin(),
+                    doc.custom_element_reaction_stack(),
                     can_gc,
                 );
                 // Step switch-1. Parse HTML from a string given document and compliantString.
@@ -131,6 +132,7 @@ impl DOMParserMethods<crate::DomTypeHolder> for DOMParser {
                     false,
                     Some(doc.insecure_requests_policy()),
                     doc.has_trustworthy_ancestor_or_current_origin(),
+                    doc.custom_element_reaction_stack(),
                     can_gc,
                 );
                 // Step switch-1. Create an XML parser parser, associated with document,

components/script/dom/node.rs

@@ -326,7 +326,7 @@ impl Node {
 
     /// Implements the "unsafely set HTML" algorithm as specified in:
     /// <https://html.spec.whatwg.org/multipage/#concept-unsafely-set-html>
-    pub fn unsafely_set_html(
+    pub(crate) fn unsafely_set_html(
         target: &Node,
         context_element: &Element,
         html: DOMString,
@@ -2926,6 +2926,7 @@ impl Node {
                     document.allow_declarative_shadow_roots(),
                     Some(document.insecure_requests_policy()),
                     document.has_trustworthy_ancestor_or_current_origin(),
+                    document.custom_element_reaction_stack(),
                     can_gc,
                 );
                 DomRoot::upcast::<Node>(document)

components/script/dom/servoparser/async_html.rs

@@ -8,6 +8,7 @@ use std::borrow::Cow;
 use std::cell::{Cell, Ref, RefCell, RefMut};
 use std::collections::HashMap;
 use std::collections::vec_deque::VecDeque;
+use std::rc::Rc;
 use std::thread;
 
 use crossbeam_channel::{Receiver, Sender, unbounded};
@@ -29,6 +30,7 @@ use crate::dom::bindings::inheritance::Castable;
 use crate::dom::bindings::root::{Dom, DomRoot};
 use crate::dom::bindings::str::DOMString;
 use crate::dom::comment::Comment;
+use crate::dom::customelementregistry::CustomElementReactionStack;
 use crate::dom::document::Document;
 use crate::dom::documenttype::DocumentType;
 use crate::dom::element::{Element, ElementCreator};
@@ -228,6 +230,8 @@ pub(crate) struct Tokenizer {
     #[no_trace]
     url: ServoUrl,
     parsing_algorithm: ParsingAlgorithm,
+    #[conditional_malloc_size_of]
+    custom_element_reaction_stack: Rc<CustomElementReactionStack>,
 }
 
 impl Tokenizer {
@@ -246,6 +250,7 @@ impl Tokenizer {
             None => ParsingAlgorithm::Normal,
         };
 
+        let custom_element_reaction_stack = document.custom_element_reaction_stack();
         let tokenizer = Tokenizer {
             document: Dom::from_ref(document),
             receiver: tokenizer_receiver,
@@ -253,6 +258,7 @@ impl Tokenizer {
             nodes: RefCell::new(HashMap::new()),
             url,
             parsing_algorithm: algorithm,
+            custom_element_reaction_stack,
         };
         tokenizer.insert_node(0, Dom::from_ref(document.upcast()));
 
@@ -397,7 +403,14 @@ impl Tokenizer {
             .GetParentNode()
             .expect("append_before_sibling called on node without parent");
 
-        super::insert(parent, Some(sibling), node, self.parsing_algorithm, can_gc);
+        super::insert(
+            parent,
+            Some(sibling),
+            node,
+            self.parsing_algorithm,
+            &self.custom_element_reaction_stack,
+            can_gc,
+        );
     }
 
     fn append(&self, parent: ParseNodeId, node: NodeOrText, can_gc: CanGc) {
@@ -409,7 +422,14 @@ impl Tokenizer {
         };
 
         let parent = &**self.get_node(&parent);
-        super::insert(parent, None, node, self.parsing_algorithm, can_gc);
+        super::insert(
+            parent,
+            None,
+            node,
+            self.parsing_algorithm,
+            &self.custom_element_reaction_stack,
+            can_gc,
+        );
     }
 
     fn has_parent_node(&self, node: ParseNodeId) -> bool {
@@ -454,6 +474,7 @@ impl Tokenizer {
                     &self.document,
                     ElementCreator::ParserCreated(current_line),
                     ParsingAlgorithm::Normal,
+                    &self.custom_element_reaction_stack,
                     can_gc,
                 );
                 self.insert_node(node, Dom::from_ref(element.upcast()));

components/script/dom/servoparser/html.rs

@@ -52,12 +52,14 @@ impl Tokenizer {
         fragment_context: Option<super::FragmentContext>,
         parsing_algorithm: ParsingAlgorithm,
     ) -> Self {
+        let custom_element_reaction_stack = document.custom_element_reaction_stack();
         let sink = Sink {
             base_url: url,
             document: Dom::from_ref(document),
             current_line: Cell::new(1),
             script: Default::default(),
             parsing_algorithm,
+            custom_element_reaction_stack,
         };
 
         let quirks_mode = match document.quirks_mode() {

components/script/dom/servoparser/mod.rs

@@ -4,6 +4,7 @@
 
 use std::borrow::Cow;
 use std::cell::Cell;
+use std::rc::Rc;
 
 use base::cross_process_instant::CrossProcessInstant;
 use base::id::PipelineId;
@@ -57,6 +58,7 @@ use crate::dom::bindings::str::{DOMString, USVString};
 use crate::dom::characterdata::CharacterData;
 use crate::dom::comment::Comment;
 use crate::dom::csp::{CspReporting, GlobalCspReporting, Violation, parse_csp_list_from_metadata};
+use crate::dom::customelementregistry::CustomElementReactionStack;
 use crate::dom::document::{Document, DocumentSource, HasBrowsingContext, IsHTMLDocument};
 use crate::dom::documentfragment::DocumentFragment;
 use crate::dom::documenttype::DocumentType;
@@ -244,6 +246,7 @@ impl ServoParser {
             allow_declarative_shadow_roots,
             Some(context_document.insecure_requests_policy()),
             context_document.has_trustworthy_ancestor_or_current_origin(),
+            context_document.custom_element_reaction_stack(),
             can_gc,
         );
 
@@ -1156,6 +1159,7 @@ fn insert(
     reference_child: Option<&Node>,
     child: NodeOrText<Dom<Node>>,
     parsing_algorithm: ParsingAlgorithm,
+    custom_element_reaction_stack: &CustomElementReactionStack,
     can_gc: CanGc,
 ) {
     match child {
@@ -1166,11 +1170,11 @@ fn insert(
             let element_in_non_fragment =
                 parsing_algorithm != ParsingAlgorithm::Fragment && n.is::<Element>();
             if element_in_non_fragment {
-                ScriptThread::push_new_element_queue();
+                custom_element_reaction_stack.push_new_element_queue();
             }
             parent.InsertBefore(&n, reference_child, can_gc).unwrap();
             if element_in_non_fragment {
-                ScriptThread::pop_current_element_queue(can_gc);
+                custom_element_reaction_stack.pop_current_element_queue(can_gc);
             }
         },
         NodeOrText::AppendText(t) => {
@@ -1201,6 +1205,8 @@ pub(crate) struct Sink {
     current_line: Cell<u64>,
     script: MutNullableDom<HTMLScriptElement>,
     parsing_algorithm: ParsingAlgorithm,
+    #[conditional_malloc_size_of]
+    custom_element_reaction_stack: Rc<CustomElementReactionStack>,
 }
 
 impl Sink {
@@ -1278,6 +1284,7 @@ impl TreeSink for Sink {
             &self.document,
             ElementCreator::ParserCreated(self.current_line.get()),
             parsing_algorithm,
+            &self.custom_element_reaction_stack,
             CanGc::note(),
         );
         Dom::from_ref(element.upcast())
@@ -1347,6 +1354,7 @@ impl TreeSink for Sink {
             Some(sibling),
             new_node,
             self.parsing_algorithm,
+            &self.custom_element_reaction_stack,
             CanGc::note(),
         );
     }
@@ -1366,7 +1374,14 @@ impl TreeSink for Sink {
 
     #[cfg_attr(crown, allow(crown::unrooted_must_root))]
     fn append(&self, parent: &Dom<Node>, child: NodeOrText<Dom<Node>>) {
-        insert(parent, None, child, self.parsing_algorithm, CanGc::note());
+        insert(
+            parent,
+            None,
+            child,
+            self.parsing_algorithm,
+            &self.custom_element_reaction_stack,
+            CanGc::note(),
+        );
     }
 
     #[cfg_attr(crown, allow(crown::unrooted_must_root))]
@@ -1479,6 +1494,7 @@ fn create_element_for_token(
     document: &Document,
     creator: ElementCreator,
     parsing_algorithm: ParsingAlgorithm,
+    custom_element_reaction_stack: &CustomElementReactionStack,
     can_gc: CanGc,
 ) -> DomRoot<Element> {
     // Step 3.
@@ -1506,7 +1522,7 @@ fn create_element_for_token(
                 .perform_a_microtask_checkpoint(can_gc);
         }
         // Step 6.3
-        ScriptThread::push_new_element_queue()
+        custom_element_reaction_stack.push_new_element_queue()
     }
 
     // Step 7.
@@ -1544,7 +1560,7 @@ fn create_element_for_token(
     // Step 9.
     if will_execute_script {
         // Steps 9.1 - 9.2.
-        ScriptThread::pop_current_element_queue(can_gc);
+        custom_element_reaction_stack.pop_current_element_queue(can_gc);
         // Step 9.3.
         document.decrement_throw_on_dynamic_markup_insertion_counter();
     }

components/script/dom/servoparser/xml.rs

@@ -35,6 +35,7 @@ impl Tokenizer {
             current_line: Cell::new(1),
             script: Default::default(),
             parsing_algorithm: ParsingAlgorithm::Normal,
+            custom_element_reaction_stack: document.custom_element_reaction_stack(),
         };
 
         let tb = XmlTreeBuilder::new(sink, Default::default());

components/script/dom/xmldocument.rs

@@ -2,6 +2,8 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 
+use std::rc::Rc;
+
 use data_url::mime::Mime;
 use dom_struct::dom_struct;
 use net_traits::request::InsecureRequestsPolicy;
@@ -17,6 +19,7 @@ use crate::dom::bindings::inheritance::Castable;
 use crate::dom::bindings::reflector::reflect_dom_object;
 use crate::dom::bindings::root::DomRoot;
 use crate::dom::bindings::str::DOMString;
+use crate::dom::customelementregistry::CustomElementReactionStack;
 use crate::dom::document::{Document, DocumentSource, HasBrowsingContext, IsHTMLDocument};
 use crate::dom::location::Location;
 use crate::dom::node::Node;
@@ -44,6 +47,7 @@ impl XMLDocument {
         doc_loader: DocumentLoader,
         inherited_insecure_requests_policy: Option<InsecureRequestsPolicy>,
         has_trustworthy_ancestor_origin: bool,
+        custom_element_reaction_stack: Rc<CustomElementReactionStack>,
     ) -> XMLDocument {
         XMLDocument {
             document: Document::new_inherited(
@@ -64,6 +68,7 @@ impl XMLDocument {
                 false,
                 inherited_insecure_requests_policy,
                 has_trustworthy_ancestor_origin,
+                custom_element_reaction_stack,
             ),
         }
     }
@@ -82,6 +87,7 @@ impl XMLDocument {
         doc_loader: DocumentLoader,
         inherited_insecure_requests_policy: Option<InsecureRequestsPolicy>,
         has_trustworthy_ancestor_origin: bool,
+        custom_element_reaction_stack: Rc<CustomElementReactionStack>,
         can_gc: CanGc,
     ) -> DomRoot<XMLDocument> {
         let doc = reflect_dom_object(
@@ -98,6 +104,7 @@ impl XMLDocument {
                 doc_loader,
                 inherited_insecure_requests_policy,
                 has_trustworthy_ancestor_origin,
+                custom_element_reaction_stack,
             )),
             window,
             can_gc,

components/script/dom/xmlhttprequest.rs

@@ -1535,6 +1535,7 @@ impl XMLHttpRequest {
             false,
             Some(doc.insecure_requests_policy()),
             doc.has_trustworthy_ancestor_origin(),
+            doc.custom_element_reaction_stack(),
             can_gc,
         )
     }

components/script/messaging.rs

@@ -5,6 +5,7 @@
 use core::fmt;
 #[cfg(feature = "webgpu")]
 use std::cell::RefCell;
+use std::collections::HashSet;
 use std::option::Option;
 use std::result::Result;
 
@@ -397,10 +398,11 @@ impl ScriptThreadReceivers {
         &self,
         task_queue: &TaskQueue<MainThreadScriptMsg>,
         timer_scheduler: &TimerScheduler,
+        fully_active: &HashSet<PipelineId>,
     ) -> MixedMessage {
         select! {
             recv(task_queue.select()) -> msg => {
-                task_queue.take_tasks(msg.unwrap());
+                task_queue.take_tasks(msg.unwrap(), fully_active);
                 let event = task_queue
                     .recv()
                     .expect("Spurious wake-up of the event-loop, task-queue has no tasks available");
@@ -437,6 +439,7 @@ impl ScriptThreadReceivers {
     pub(crate) fn try_recv(
         &self,
         task_queue: &TaskQueue<MainThreadScriptMsg>,
+        fully_active: &HashSet<PipelineId>,
     ) -> Option<MixedMessage> {
         if let Ok(message) = self.constellation_receiver.try_recv() {
             let message = message
@@ -449,7 +452,7 @@ impl ScriptThreadReceivers {
                 .ok()?;
             return MixedMessage::FromConstellation(message).into();
         }
-        if let Ok(message) = task_queue.take_tasks_and_recv() {
+        if let Ok(message) = task_queue.take_tasks_and_recv(fully_active) {
             return MixedMessage::FromScript(message).into();
         }
         if let Ok(message) = self.devtools_server_receiver.try_recv() {

components/script/script_thread.rs

@@ -279,7 +279,7 @@ pub struct ScriptThread {
     docs_with_no_blocking_loads: DomRefCell<HashSet<Dom<Document>>>,
 
     /// <https://html.spec.whatwg.org/multipage/#custom-element-reactions-stack>
-    custom_element_reaction_stack: CustomElementReactionStack,
+    custom_element_reaction_stack: Rc<CustomElementReactionStack>,
 
     /// Cross-process access to the compositor's API.
     #[no_trace]
@@ -723,10 +723,8 @@ impl ScriptThread {
         with_script_thread(|script_thread| script_thread.is_user_interacting.get())
     }
 
-    pub(crate) fn get_fully_active_document_ids() -> HashSet<PipelineId> {
+    pub(crate) fn get_fully_active_document_ids(&self) -> HashSet<PipelineId> {
-        with_script_thread(|script_thread| {
+        self.documents
-            script_thread
-                .documents
             .borrow()
             .iter()
             .filter_map(|(id, document)| {
@@ -740,7 +738,6 @@ impl ScriptThread {
                 let _ = set.insert(id);
                 set
             })
-        })
     }
 
     pub(crate) fn find_window_proxy(id: BrowsingContextId) -> Option<DomRoot<WindowProxy>> {
@@ -810,19 +807,13 @@ impl ScriptThread {
             .register_paint_worklet_modules(name, properties, painter);
     }
 
-    pub(crate) fn push_new_element_queue() {
+    pub(crate) fn custom_element_reaction_stack() -> Rc<CustomElementReactionStack> {
-        with_script_thread(|script_thread| {
+        with_optional_script_thread(|script_thread| {
             script_thread
+                .as_ref()
+                .unwrap()
                 .custom_element_reaction_stack
-                .push_new_element_queue();
+                .clone()
-        })
-    }
-
-    pub(crate) fn pop_current_element_queue(can_gc: CanGc) {
-        with_script_thread(|script_thread| {
-            script_thread
-                .custom_element_reaction_stack
-                .pop_current_element_queue(can_gc);
         })
     }
 
@@ -1006,7 +997,7 @@ impl ScriptThread {
             webxr_registry: state.webxr_registry,
             worklet_thread_pool: Default::default(),
             docs_with_no_blocking_loads: Default::default(),
-            custom_element_reaction_stack: CustomElementReactionStack::new(),
+            custom_element_reaction_stack: Rc::new(CustomElementReactionStack::new()),
             compositor_api: state.compositor_api,
             profile_script_events: opts.debug.profile_script_events,
             print_pwm: opts.print_pwm,
@@ -1352,9 +1343,12 @@ impl ScriptThread {
 
         // Receive at least one message so we don't spinloop.
         debug!("Waiting for event.");
-        let mut event = self
+        let fully_active = self.get_fully_active_document_ids();
-            .receivers
+        let mut event = self.receivers.recv(
-            .recv(&self.task_queue, &self.timer_scheduler.borrow());
+            &self.task_queue,
+            &self.timer_scheduler.borrow(),
+            &fully_active,
+        );
 
         loop {
             debug!("Handling event: {event:?}");
@@ -1464,7 +1458,7 @@ impl ScriptThread {
             // If any of our input sources has an event pending, we'll perform another iteration
             // and check for more resize events. If there are no events pending, we'll move
             // on and execute the sequential non-resize events we've seen.
-            match self.receivers.try_recv(&self.task_queue) {
+            match self.receivers.try_recv(&self.task_queue, &fully_active) {
                 Some(new_event) => event = new_event,
                 None => break,
             }
@@ -3422,6 +3416,7 @@ impl ScriptThread {
             true,
             incomplete.load_data.inherited_insecure_requests_policy,
             incomplete.load_data.has_trustworthy_ancestor_origin,
+            self.custom_element_reaction_stack.clone(),
             can_gc,
         );
 

components/script/task_queue.rs

@@ -15,7 +15,6 @@ use strum::VariantArray;
 use crate::dom::bindings::cell::DomRefCell;
 use crate::dom::worker::TrustedWorkerAddress;
 use crate::script_runtime::ScriptThreadEventCategory;
-use crate::script_thread::ScriptThread;
 use crate::task::TaskBox;
 use crate::task_source::TaskSourceName;
 
@@ -197,19 +196,18 @@ impl<T: QueuedTaskConversion> TaskQueue<T> {
     }
 
     /// Take all tasks again and then run `recv()`.
-    pub(crate) fn take_tasks_and_recv(&self) -> Result<T, ()> {
+    pub(crate) fn take_tasks_and_recv(&self, fully_active: &HashSet<PipelineId>) -> Result<T, ()> {
-        self.take_tasks(T::wake_up_msg());
+        self.take_tasks(T::wake_up_msg(), fully_active);
         self.recv()
     }
 
     /// Drain the queue for the current iteration of the event-loop.
     /// Holding-back throttles above a given high-water mark.
-    pub(crate) fn take_tasks(&self, first_msg: T) {
+    pub(crate) fn take_tasks(&self, first_msg: T, fully_active: &HashSet<PipelineId>) {
         // High-watermark: once reached, throttled tasks will be held-back.
         const PER_ITERATION_MAX: u64 = 5;
-        let fully_active = ScriptThread::get_fully_active_document_ids();
         // Always first check for new tasks, but don't reset 'taken_task_counter'.
-        self.process_incoming_tasks(first_msg, &fully_active);
+        self.process_incoming_tasks(first_msg, fully_active);
         let mut throttled = self.throttled.borrow_mut();
         let mut throttled_length: usize = throttled.values().map(|queue| queue.len()).sum();
         let mut task_source_cycler = TaskSourceName::VARIANTS.iter().cycle();