script/dom/workers/

dedicatedworkerglobalscope.rs

/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/. */

#![cfg_attr(crown, allow(crown::jscontext_first_arg))]

use std::cell::Cell;
use std::collections::VecDeque;
use std::sync::Arc;
use std::sync::atomic::{AtomicBool, Ordering};
use std::thread::{self, JoinHandle};

use crossbeam_channel::{Receiver, Sender, unbounded};
#[cfg(feature = "devtools")]
use devtools_traits::DevtoolScriptControlMsg;
use dom_struct::dom_struct;
use fonts::FontContext;
use js::context::JSContext;
use js::jsapi::{Heap, JSObject};
use js::jsval::UndefinedValue;
use js::rust::{CustomAutoRooterGuard, HandleValue};
use net_traits::blob_url_store::UrlWithBlobClaim;
use net_traits::image_cache::ImageCache;
use net_traits::policy_container::PolicyContainer;
use net_traits::request::{
    CredentialsMode, Destination, InsecureRequestsPolicy, Origin, ParserMetadata,
    PreloadedResources, Referrer, RequestBuilder, RequestClient, RequestMode,
};
use script_bindings::cell::DomRefCell;
use script_bindings::interfaces::HasOrigin;
use servo_base::generic_channel::{self, GenericReceiver, GenericSender, RoutedReceiver};
use servo_base::id::{BrowsingContextId, PipelineId, ScriptEventLoopId, WebViewId};
use servo_constellation_traits::{
    ScriptToConstellationMessage, WorkerAnimationFrameTick, WorkerGlobalScopeInit,
    WorkerScriptLoadOrigin,
};
use servo_url::{ImmutableOrigin, MutableOrigin, ServoUrl};
use style::thread_state::{self, ThreadState};

use crate::conversions::Convert;
use crate::dom::abstractworker::{MessageData, SimpleWorkerErrorHandler, WorkerScriptMsg};
use crate::dom::abstractworkerglobalscope::{WorkerEventLoopMethods, run_worker_event_loop};
use crate::dom::bindings::callback::{ExceptionHandling, RootedCallback, TracedCallback};
use crate::dom::bindings::codegen::Bindings::AnimationFrameProviderBinding::FrameRequestCallback;
use crate::dom::bindings::codegen::Bindings::DedicatedWorkerGlobalScopeBinding;
use crate::dom::bindings::codegen::Bindings::DedicatedWorkerGlobalScopeBinding::DedicatedWorkerGlobalScopeMethods;
use crate::dom::bindings::codegen::Bindings::MessagePortBinding::StructuredSerializeOptions;
use crate::dom::bindings::codegen::Bindings::PerformanceBinding::PerformanceMethods;
use crate::dom::bindings::codegen::Bindings::WorkerBinding::{WorkerOptions, WorkerType};
use crate::dom::bindings::error::{Error, ErrorInfo, ErrorResult, Fallible};
use crate::dom::bindings::inheritance::Castable;
use crate::dom::bindings::num::Finite;
use crate::dom::bindings::refcounted::Trusted;
use crate::dom::bindings::reflector::DomGlobal;
use crate::dom::bindings::root::DomRoot;
use crate::dom::bindings::str::DOMString;
use crate::dom::bindings::structuredclone;
use crate::dom::bindings::trace::{CustomTraceable, RootedTraceableBox};
use crate::dom::csp::Violation;
use crate::dom::errorevent::ErrorEvent;
use crate::dom::event::{Event, EventBubbles, EventCancelable};
use crate::dom::eventtarget::EventTarget;
use crate::dom::globalscope::GlobalScope;
use crate::dom::html::htmlscriptelement::Script;
use crate::dom::messageevent::MessageEvent;
#[cfg(feature = "devtools")]
use crate::dom::types::DebuggerGlobalScope;
#[cfg(feature = "webgpu")]
use crate::dom::webgpu::identityhub::IdentityHub;
use crate::dom::worker::{TrustedWorkerAddress, Worker};
use crate::dom::workerglobalscope::{
    ScriptFetchContext, WorkerDevtoolsControlMsg, WorkerGlobalScope,
};
use crate::messaging::{CommonScriptMsg, ScriptEventLoopReceiver, ScriptEventLoopSender};
use crate::realms::enter_auto_realm;
use crate::runtime::script_runtime::ScriptThreadEventCategory::WorkerEvent;
use crate::runtime::script_runtime::{IntroductionType, Runtime, ThreadSafeJSContext};
use crate::scripting::script_module::fetch_a_module_script_graph;
use crate::tasks::task_queue::{QueuedTask, QueuedTaskConversion, TaskQueue};
use crate::tasks::task_source::TaskSourceName;

/// 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
/// providing a reference that can be cloned freely.
pub(crate) struct AutoWorkerReset<'a> {
    workerscope: &'a DedicatedWorkerGlobalScope,
    old_worker: Option<TrustedWorkerAddress>,
}

impl<'a> AutoWorkerReset<'a> {
    pub(crate) fn new(
        workerscope: &'a DedicatedWorkerGlobalScope,
        worker: TrustedWorkerAddress,
    ) -> AutoWorkerReset<'a> {
        let old_worker = workerscope.replace_worker(Some(worker));
        AutoWorkerReset {
            workerscope,
            old_worker,
        }
    }
}

impl Drop for AutoWorkerReset<'_> {
    fn drop(&mut self) {
        self.workerscope
            .replace_worker(std::mem::take(&mut self.old_worker));
    }
}

/// Messages sent from the owning global.
pub(crate) enum DedicatedWorkerControlMsg {
    /// Shutdown the worker.
    Exit,
    AnimationFrameProviderUnsupported,
}

pub(crate) enum DedicatedWorkerScriptMsg {
    /// Standard message from a worker.
    CommonWorker(TrustedWorkerAddress, WorkerScriptMsg),
    /// Wake-up call from the task queue.
    WakeUp,
}

pub(crate) enum MixedMessage {
    Worker(DedicatedWorkerScriptMsg),
    #[cfg(feature = "devtools")]
    Devtools(DevtoolScriptControlMsg),
    Control(DedicatedWorkerControlMsg),
    AnimationFrameTick(WorkerAnimationFrameTick),
    Timer,
}

impl QueuedTaskConversion for DedicatedWorkerScriptMsg {
    fn task_source_name(&self) -> Option<&TaskSourceName> {
        let common_worker_msg = match self {
            DedicatedWorkerScriptMsg::CommonWorker(_, common_worker_msg) => common_worker_msg,
            _ => return None,
        };
        let script_msg = match common_worker_msg {
            WorkerScriptMsg::Common(script_msg) => script_msg,
            _ => return None,
        };
        match script_msg {
            CommonScriptMsg::Task(_category, _boxed, _pipeline_id, source_name) => {
                Some(source_name)
            },
            _ => None,
        }
    }

    fn pipeline_id(&self) -> Option<PipelineId> {
        // Workers always return None, since the pipeline_id is only used to check for document activity,
        // and this check does not apply to worker event-loops.
        None
    }

    fn into_queued_task(self) -> Option<QueuedTask> {
        let (worker, common_worker_msg) = match self {
            DedicatedWorkerScriptMsg::CommonWorker(worker, common_worker_msg) => {
                (worker, common_worker_msg)
            },
            _ => return None,
        };
        let script_msg = match common_worker_msg {
            WorkerScriptMsg::Common(script_msg) => script_msg,
            _ => return None,
        };
        let (event_category, task, pipeline_id, task_source) = match script_msg {
            CommonScriptMsg::Task(category, boxed, pipeline_id, task_source) => {
                (category, boxed, pipeline_id, task_source)
            },
            _ => return None,
        };
        Some(QueuedTask {
            worker: Some(worker),
            event_category,
            task,
            pipeline_id,
            task_source,
        })
    }

    fn from_queued_task(queued_task: QueuedTask) -> Self {
        let script_msg = CommonScriptMsg::Task(
            queued_task.event_category,
            queued_task.task,
            queued_task.pipeline_id,
            queued_task.task_source,
        );
        DedicatedWorkerScriptMsg::CommonWorker(
            queued_task.worker.unwrap(),
            WorkerScriptMsg::Common(script_msg),
        )
    }

    fn inactive_msg() -> Self {
        // Inactive is only relevant in the context of a browsing-context event-loop.
        panic!("Workers should never receive messages marked as inactive");
    }

    fn wake_up_msg() -> Self {
        DedicatedWorkerScriptMsg::WakeUp
    }

    fn is_wake_up(&self) -> bool {
        matches!(self, DedicatedWorkerScriptMsg::WakeUp)
    }
}

unsafe_no_jsmanaged_fields!(TaskQueue<DedicatedWorkerScriptMsg>);

/// <https://html.spec.whatwg.org/multipage/#dedicatedworkerglobalscope>
#[dom_struct]
pub(crate) struct DedicatedWorkerGlobalScope {
    workerglobalscope: WorkerGlobalScope,
    /// The [`WebViewId`] of the `WebView` that this worker is associated with.
    #[no_trace]
    webview_id: WebViewId,
    #[ignore_malloc_size_of = "Defined in std"]
    task_queue: TaskQueue<DedicatedWorkerScriptMsg>,
    own_sender: Sender<DedicatedWorkerScriptMsg>,
    worker: DomRefCell<Option<TrustedWorkerAddress>>,
    /// Sender to the parent thread.
    parent_event_loop_sender: ScriptEventLoopSender,
    #[ignore_malloc_size_of = "ImageCache"]
    #[no_trace]
    image_cache: Arc<dyn ImageCache>,
    #[no_trace]
    browsing_context: Option<BrowsingContextId>,
    #[conditional_malloc_size_of]
    animation_frame_provider_supported: Arc<AtomicBool>,
    animation_frame_provider_registered: Cell<bool>,
    /// <https://html.spec.whatwg.org/multipage/#animation-frame-callback-identifier>
    animation_frame_ident: Cell<u32>,
    /// Pending animation frame callbacks for a later worker rendering update.
    #[ignore_malloc_size_of = "closures are hard"]
    animation_frame_list: DomRefCell<VecDeque<(u32, TracedCallback<FrameRequestCallback>)>>,
    /// Callbacks snapshotted for the current worker rendering update.
    #[ignore_malloc_size_of = "closures are hard"]
    current_animation_frame_list: DomRefCell<VecDeque<(u32, TracedCallback<FrameRequestCallback>)>>,
    /// Whether we're in the process of running animation callbacks.
    running_animation_callbacks: Cell<bool>,
    /// Whether Constellation currently treats this worker as having callbacks.
    animation_frame_callbacks_active: Cell<bool>,
    /// A sender for animation frame ticks.
    #[no_trace]
    #[ignore_malloc_size_of = "channels are hard"]
    animation_frame_tick_sender: Option<GenericSender<WorkerAnimationFrameTick>>,
    /// A receiver for animation frame ticks.
    #[no_trace]
    #[ignore_malloc_size_of = "channels are hard"]
    animation_frame_tick_receiver: Option<RoutedReceiver<WorkerAnimationFrameTick>>,
    /// A receiver of control messages.
    #[no_trace]
    control_receiver: Receiver<DedicatedWorkerControlMsg>,
    #[no_trace]
    queued_worker_tasks: DomRefCell<Vec<MessageData>>,
}

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, cx: &mut JSContext) -> bool {
        self.handle_mixed_message(event, cx)
    }

    fn handle_worker_post_event(
        &self,
        worker: &TrustedWorkerAddress,
    ) -> Option<AutoWorkerReset<'_>> {
        let ar = AutoWorkerReset::new(self, worker.clone());
        Some(ar)
    }

    fn from_control_msg(msg: DedicatedWorkerControlMsg) -> MixedMessage {
        MixedMessage::Control(msg)
    }

    fn from_worker_msg(msg: DedicatedWorkerScriptMsg) -> MixedMessage {
        MixedMessage::Worker(msg)
    }

    #[cfg(feature = "devtools")]
    fn from_devtools_msg(msg: DevtoolScriptControlMsg) -> MixedMessage {
        MixedMessage::Devtools(msg)
    }

    fn from_timer_msg() -> MixedMessage {
        MixedMessage::Timer
    }

    fn from_animation_frame_tick_msg(msg: WorkerAnimationFrameTick) -> Option<MixedMessage> {
        Some(MixedMessage::AnimationFrameTick(msg))
    }

    fn animation_frame_tick_receiver(&self) -> Option<&RoutedReceiver<WorkerAnimationFrameTick>> {
        self.animation_frame_tick_receiver.as_ref()
    }

    fn control_receiver(&self) -> &Receiver<DedicatedWorkerControlMsg> {
        &self.control_receiver
    }
}

impl DedicatedWorkerGlobalScope {
    #[allow(clippy::too_many_arguments)]
    fn new_inherited(
        init: WorkerGlobalScopeInit,
        webview_id: WebViewId,
        worker_name: DOMString,
        worker_type: WorkerType,
        worker_url: ServoUrl,
        from_devtools_receiver: Option<RoutedReceiver<WorkerDevtoolsControlMsg>>,
        runtime: Runtime,
        parent_event_loop_sender: ScriptEventLoopSender,
        own_sender: Sender<DedicatedWorkerScriptMsg>,
        receiver: Receiver<DedicatedWorkerScriptMsg>,
        closing: Arc<AtomicBool>,
        animation_frame_provider_supported: Arc<AtomicBool>,
        image_cache: Arc<dyn ImageCache>,
        browsing_context: Option<BrowsingContextId>,
        animation_frame_tick_sender: Option<GenericSender<WorkerAnimationFrameTick>>,
        animation_frame_tick_receiver: Option<RoutedReceiver<WorkerAnimationFrameTick>>,
        #[cfg(feature = "webgpu")] gpu_id_hub: Arc<IdentityHub>,
        control_receiver: Receiver<DedicatedWorkerControlMsg>,
        insecure_requests_policy: InsecureRequestsPolicy,
        font_context: Arc<FontContext>,
    ) -> DedicatedWorkerGlobalScope {
        DedicatedWorkerGlobalScope {
            workerglobalscope: WorkerGlobalScope::new_inherited(
                init,
                worker_name,
                worker_type,
                worker_url,
                runtime,
                from_devtools_receiver,
                closing,
                #[cfg(feature = "webgpu")]
                gpu_id_hub,
                insecure_requests_policy,
                font_context,
                None,
            ),
            webview_id,
            task_queue: TaskQueue::new(receiver, own_sender.clone()),
            own_sender,
            parent_event_loop_sender,
            worker: DomRefCell::new(None),
            image_cache,
            browsing_context,
            animation_frame_provider_supported,
            animation_frame_provider_registered: Cell::new(false),
            animation_frame_ident: Cell::new(0),
            animation_frame_list: DomRefCell::new(VecDeque::new()),
            current_animation_frame_list: DomRefCell::new(VecDeque::new()),
            running_animation_callbacks: Cell::new(false),
            animation_frame_callbacks_active: Cell::new(false),
            animation_frame_tick_sender,
            animation_frame_tick_receiver,
            control_receiver,
            queued_worker_tasks: Default::default(),
        }
    }

    #[expect(clippy::too_many_arguments)]
    pub(crate) fn new(
        init: WorkerGlobalScopeInit,
        webview_id: WebViewId,
        worker_name: DOMString,
        worker_type: WorkerType,
        worker_url: ServoUrl,
        from_devtools_receiver: Option<RoutedReceiver<WorkerDevtoolsControlMsg>>,
        runtime: Runtime,
        parent_event_loop_sender: ScriptEventLoopSender,
        own_sender: Sender<DedicatedWorkerScriptMsg>,
        receiver: Receiver<DedicatedWorkerScriptMsg>,
        closing: Arc<AtomicBool>,
        animation_frame_provider_supported: Arc<AtomicBool>,
        image_cache: Arc<dyn ImageCache>,
        browsing_context: Option<BrowsingContextId>,
        animation_frame_tick_sender: Option<GenericSender<WorkerAnimationFrameTick>>,
        animation_frame_tick_receiver: Option<RoutedReceiver<WorkerAnimationFrameTick>>,
        #[cfg(feature = "webgpu")] gpu_id_hub: Arc<IdentityHub>,
        control_receiver: Receiver<DedicatedWorkerControlMsg>,
        insecure_requests_policy: InsecureRequestsPolicy,
        font_context: Arc<FontContext>,
        #[cfg(feature = "devtools")] debugger_global: &DebuggerGlobalScope,
        cx: &mut js::context::JSContext,
    ) -> DomRoot<DedicatedWorkerGlobalScope> {
        let scope = Box::new(DedicatedWorkerGlobalScope::new_inherited(
            init,
            webview_id,
            worker_name,
            worker_type,
            worker_url,
            from_devtools_receiver,
            runtime,
            parent_event_loop_sender,
            own_sender,
            receiver,
            closing,
            animation_frame_provider_supported,
            image_cache,
            browsing_context,
            animation_frame_tick_sender,
            animation_frame_tick_receiver,
            #[cfg(feature = "webgpu")]
            gpu_id_hub,
            control_receiver,
            insecure_requests_policy,
            font_context,
        ));
        let scope = DedicatedWorkerGlobalScopeBinding::Wrap::<crate::DomTypeHolder>(
            cx,
            &scope.origin(),
            scope,
        );
        #[cfg(feature = "devtools")]
        scope
            .upcast::<WorkerGlobalScope>()
            .init_debugger_global(Some(debugger_global), cx);

        scope
    }

    /// <https://html.spec.whatwg.org/multipage/#run-a-worker>
    #[expect(unsafe_code)]
    #[allow(clippy::too_many_arguments)]
    pub(crate) fn run_worker_scope(
        mut init: WorkerGlobalScopeInit,
        webview_id: WebViewId,
        worker_url: UrlWithBlobClaim,
        #[cfg(feature = "devtools")] from_devtools_receiver: GenericReceiver<
            DevtoolScriptControlMsg,
        >,
        worker: TrustedWorkerAddress,
        parent_event_loop_sender: ScriptEventLoopSender,
        own_sender: Sender<DedicatedWorkerScriptMsg>,
        receiver: Receiver<DedicatedWorkerScriptMsg>,
        worker_load_origin: WorkerScriptLoadOrigin,
        worker_options: &WorkerOptions,
        closing: Arc<AtomicBool>,
        animation_frame_provider_supported: Arc<AtomicBool>,
        image_cache: Arc<dyn ImageCache>,
        browsing_context: Option<BrowsingContextId>,
        #[cfg(feature = "webgpu")] gpu_id_hub: Arc<IdentityHub>,
        control_receiver: Receiver<DedicatedWorkerControlMsg>,
        context_sender: Sender<ThreadSafeJSContext>,
        insecure_requests_policy: InsecureRequestsPolicy,
        policy_container: Arc<PolicyContainer>,
        font_context: Arc<FontContext>,
    ) -> JoinHandle<()> {
        let event_loop_id = ScriptEventLoopId::installed()
            .expect("Should always be in a ScriptThread or in a dedicated worker");
        let current_global = GlobalScope::current().expect("No current global object");
        let origin = current_global.origin().immutable().clone();
        let referrer = current_global.get_referrer();
        let parent = current_global.runtime_handle();
        let current_global_ancestor_trustworthy = current_global.has_trustworthy_ancestor_origin();
        let is_secure_context = current_global.is_secure_context();
        let is_nested_browsing_context = current_global.is_nested_browsing_context();

        let worker_type = worker_options.type_;
        let worker_name = worker_options.name.to_string();
        let credentials = worker_options.credentials.convert();

        thread::Builder::new()
            .name(format!("WW:{}", worker_url.debug_compact()))
            .spawn(move || {
                thread_state::initialize(ThreadState::SCRIPT | ThreadState::IN_WORKER);
                ScriptEventLoopId::install(event_loop_id);

                let WorkerScriptLoadOrigin {
                    referrer_url,
                    pipeline_id,
                    ..
                } = worker_load_origin;

                let referrer = referrer_url.map(Referrer::ReferrerUrl).unwrap_or(referrer);

                let request_client = RequestClient {
                    preloaded_resources: PreloadedResources::default(),
                    policy_container,
                    origin: Origin::Origin(origin.clone()),
                    is_nested_browsing_context,
                    insecure_requests_policy,
                    has_trustworthy_ancestor_origin: current_global_ancestor_trustworthy,
                };

                let event_loop_sender = ScriptEventLoopSender::DedicatedWorker {
                    sender: own_sender.clone(),
                    main_thread_worker: worker.clone(),
                };

                let runtime = unsafe {
                    Runtime::new_with_parent(Some(parent), Some(event_loop_sender.clone()))
                };
                // SAFETY: We are in a new thread, so this first cx.
                // It is OK to have it separated of runtime here,
                // because it will never outlive it (runtime destruction happens at the end of this function)
                let mut cx = unsafe { runtime.cx() };
                let cx = &mut cx;
                #[cfg(feature = "devtools")]
                let debugger_global = DebuggerGlobalScope::new(
                    pipeline_id,
                    init.to_devtools_sender.clone(),
                    init.from_devtools_sender
                        .clone()
                        .expect("Guaranteed by Worker::Constructor"),
                    init.mem_profiler_chan.clone(),
                    init.time_profiler_chan.clone(),
                    init.script_to_constellation_chan.clone(),
                    init.script_to_embedder_chan.clone(),
                    init.resource_threads.clone(),
                    init.storage_threads.clone(),
                    #[cfg(feature = "webgpu")]
                    gpu_id_hub.clone(),
                    cx,
                );
                #[cfg(feature = "devtools")]
                debugger_global.execute(cx);

                let context_for_interrupt = runtime.thread_safe_js_context();
                let _ = context_sender.send(context_for_interrupt);

                #[cfg(feature = "devtools")]
                let devtools_mpsc_port = Some(from_devtools_receiver.route_preserving_errors());
                #[cfg(not(feature = "devtools"))]
                let devtools_mpsc_port = None;
                let animation_frame_channel = init
                    .animation_frame_provider_supported
                    .then(|| generic_channel::channel().expect("Failed to create generic channel"));
                let (animation_frame_tick_sender, animation_frame_tick_receiver) =
                    match animation_frame_channel {
                        Some((sender, receiver)) => {
                            (Some(sender), Some(receiver.route_preserving_errors()))
                        },
                        None => (None, None),
                    };

                // Step 8 "Set up a worker environment settings object [...]"
                //
                // <https://html.spec.whatwg.org/multipage/#script-settings-for-workers>
                //
                // > The origin: Return a unique opaque origin if `worker global
                // > scope`'s url's scheme is "data", and `inherited origin`
                // > otherwise.
                if worker_url.scheme() == "data" {
                    // Workers created from a data: url are secure if they were created from secure contexts
                    if is_secure_context {
                        init.origin = ImmutableOrigin::new_opaque_data_url_worker();
                    } else {
                        init.origin = ImmutableOrigin::new_opaque();
                    }
                }

                let worker_id = init.worker_id;
                #[cfg(feature = "devtools")]
                let devtools_enabled = init.to_devtools_sender.is_some();
                let global = DedicatedWorkerGlobalScope::new(
                    init,
                    webview_id,
                    worker_name.into(),
                    worker_type,
                    worker_url.url(),
                    devtools_mpsc_port,
                    runtime,
                    parent_event_loop_sender,
                    own_sender,
                    receiver,
                    closing,
                    animation_frame_provider_supported,
                    image_cache,
                    browsing_context,
                    animation_frame_tick_sender,
                    animation_frame_tick_receiver,
                    #[cfg(feature = "webgpu")]
                    gpu_id_hub,
                    control_receiver,
                    insecure_requests_policy,
                    font_context,
                    #[cfg(feature = "devtools")]
                    &debugger_global,
                    cx,
                );

                #[cfg(feature = "devtools")]
                if devtools_enabled {
                    debugger_global.fire_add_debuggee(
                        cx,
                        global.upcast(),
                        pipeline_id,
                        Some(worker_id),
                    );
                }
                let scope = global.upcast::<WorkerGlobalScope>();
                let global_scope = global.upcast::<GlobalScope>();

                // Step 12. Obtain script by switching on options["type"]:
                {
                    let _ar = AutoWorkerReset::new(&global, worker.clone());
                    match worker_type {
                        WorkerType::Classic => {
                            fetch_a_classic_worker_script(
                                scope,
                                worker_url,
                                request_client,
                                Destination::Worker,
                                Some(webview_id),
                                referrer,
                            );
                        },
                        WorkerType::Module => {
                            let worker_scope = DomRoot::from_ref(scope);
                            fetch_a_module_script_graph(
                                cx,
                                global_scope,
                                worker_url,
                                request_client,
                                Destination::Worker,
                                referrer,
                                credentials,
                                Some(IntroductionType::WORKER),
                                move |cx, module_tree| {
                                    worker_scope.on_complete(cx, module_tree.map(Script::Module));
                                },
                            );
                        },
                    }

                    let reporter_name = format!("dedicated-worker-reporter-{}", worker_id);
                    scope
                        .upcast::<GlobalScope>()
                        .mem_profiler_chan()
                        .run_with_memory_reporting(
                            || {
                                // Step 27, Run the responsible event loop specified
                                // by inside settings until it is destroyed.
                                // The worker processing model remains on this step
                                // until the event loop is destroyed,
                                // which happens after the closing flag is set to true.
                                while !scope.is_closing() {
                                    run_worker_event_loop(&*global, Some(&worker), cx);
                                }
                            },
                            reporter_name,
                            event_loop_sender,
                            CommonScriptMsg::CollectReports,
                        );
                }

                // Drop worker rAF state before destroying the JS runtime.
                global.clear_animation_frame_callbacks_and_unregister();
                scope.clear_js_runtime();
            })
            .expect("Thread spawning failed")
    }

    pub(crate) fn webview_id(&self) -> WebViewId {
        self.webview_id
    }

    pub(crate) fn animation_frame_provider_supported(&self) -> bool {
        self.animation_frame_provider_supported
            .load(Ordering::SeqCst)
    }

    pub(crate) fn animation_frame_provider_supported_flag(&self) -> Arc<AtomicBool> {
        self.animation_frame_provider_supported.clone()
    }

    fn register_animation_frame_provider(&self) {
        if !self.animation_frame_provider_supported() {
            return;
        }

        let Some(sender) = self.animation_frame_tick_sender.clone() else {
            return;
        };

        if self.animation_frame_provider_registered.replace(true) {
            return;
        }

        let worker_id = self.upcast::<WorkerGlobalScope>().worker_id();
        log::debug!(
            "Registering dedicated worker animation frame provider: worker={worker_id:?} ---->"
        );
        let _ = self
            .upcast::<GlobalScope>()
            .script_to_constellation_chan()
            .send(
                ScriptToConstellationMessage::RegisterWorkerAnimationFrameProvider(
                    worker_id, sender,
                ),
            );
    }

    fn unregister_animation_frame_provider(&self) {
        if !self.animation_frame_provider_registered.replace(false) {
            return;
        }

        self.animation_frame_callbacks_active.set(false);
        let worker_id = self.upcast::<WorkerGlobalScope>().worker_id();
        log::debug!(
            "Unregistering dedicated worker animation frame provider: worker={worker_id:?} ---->"
        );
        let _ = self
            .upcast::<GlobalScope>()
            .script_to_constellation_chan()
            .send(ScriptToConstellationMessage::UnregisterWorkerAnimationFrameProvider(worker_id));
    }

    fn send_animation_frame_callbacks_state(&self, active: bool) {
        if !self.animation_frame_provider_supported() {
            return;
        }

        let worker_id = self.upcast::<WorkerGlobalScope>().worker_id();
        log::debug!(
            "Sending dedicated worker animation frame state: worker={worker_id:?}, active={active} ---->",
        );
        let _ = self
            .upcast::<GlobalScope>()
            .script_to_constellation_chan()
            .send(
                ScriptToConstellationMessage::ChangeWorkerAnimationFrameProviderState(
                    worker_id, active,
                ),
            );
    }

    fn set_animation_frame_callbacks_active(&self, active: bool) {
        if self.animation_frame_callbacks_active.replace(active) == active {
            return;
        }

        self.send_animation_frame_callbacks_state(active);
    }

    fn remove_animation_frame_callback_from(
        list: &DomRefCell<VecDeque<(u32, TracedCallback<FrameRequestCallback>)>>,
        ident: u32,
    ) {
        let mut list = list.borrow_mut();
        if let Some(position) = list.iter().position(|(handle, _)| *handle == ident) {
            list.remove(position);
        }
    }

    fn has_animation_frame_callbacks(&self) -> bool {
        !self.animation_frame_list.borrow().is_empty() ||
            !self.current_animation_frame_list.borrow().is_empty()
    }

    /// <https://html.spec.whatwg.org/multipage/#dom-animationframeprovider-requestanimationframe>
    pub(crate) fn request_animation_frame(
        &self,
        callback: RootedCallback<FrameRequestCallback>,
    ) -> Fallible<u32> {
        // Step 1. If this is not supported, then throw a "NotSupportedError" DOMException.
        if !self.animation_frame_provider_supported() {
            return Err(Error::NotSupported(Some(
                "Animation frame callbacks are not supported for this worker".to_owned(),
            )));
        }

        self.register_animation_frame_provider();

        // Step 2. Let target be this's target object.
        // Step 3. Increment target's animation frame callback identifier by one,
        // and let handle be the result.
        let ident = self.animation_frame_ident.get() + 1;
        self.animation_frame_ident.set(ident);

        // Step 4. Let callbacks be target's map of animation frame callbacks.
        // Step 5. Set callbacks[handle] to callback.
        self.animation_frame_list
            .borrow_mut()
            .push_back((ident, callback.to_traced()));
        log::debug!("Queued dedicated worker animation frame callback: handle={ident} ---->");
        self.set_animation_frame_callbacks_active(true);

        // Step 6. Return handle.
        Ok(ident)
    }

    /// <https://html.spec.whatwg.org/multipage/#dom-animationframeprovider-cancelanimationframe>
    pub(crate) fn cancel_animation_frame(&self, ident: u32) -> ErrorResult {
        // Step 1. If this is not supported, then throw a "NotSupportedError" DOMException.
        if !self.animation_frame_provider_supported() {
            return Err(Error::NotSupported(Some(
                "Animation frame callbacks are not supported for this worker".to_owned(),
            )));
        }

        // Step 2. Let callbacks be this's target object's map of animation frame callbacks.
        // Step 3. Remove callbacks[handle].
        Self::remove_animation_frame_callback_from(&self.animation_frame_list, ident);

        Self::remove_animation_frame_callback_from(&self.current_animation_frame_list, ident);
        log::debug!("Cancelled dedicated worker animation frame callback: handle={ident} ---->");

        if !self.running_animation_callbacks.get() && !self.has_animation_frame_callbacks() {
            self.set_animation_frame_callbacks_active(false);
        }

        Ok(())
    }

    /// <https://html.spec.whatwg.org/multipage/#run-the-animation-frame-callbacks>
    pub(crate) fn run_the_animation_frame_callbacks(&self, cx: &mut JSContext) {
        if !self.animation_frame_provider_supported() ||
            self.upcast::<WorkerGlobalScope>().is_closing()
        {
            return;
        }

        // Step 1. Let callbacks be target's map of animation frame callbacks.
        // Step 2. Let callbackHandles be the result of getting the keys of callbacks.
        let callback_count = self.animation_frame_list.borrow().len();
        log::debug!("Running dedicated worker animation frame callbacks: count={callback_count}");
        {
            let mut pending = self.animation_frame_list.borrow_mut();
            let mut current = self.current_animation_frame_list.borrow_mut();
            for _ in 0..callback_count {
                if let Some(ref callback) = pending.pop_front() {
                    current.push_back(callback.clone());
                }
            }
        }

        self.running_animation_callbacks.set(true);
        let timing = self.upcast::<GlobalScope>().performance(cx).Now();

        // Step 3. For each handle in callbackHandles, if handle exists in callbacks:
        for _ in 0..callback_count {
            // Step 3.1. Let callback be callbacks[handle].
            // Step 3.2. Remove callbacks[handle].
            rooted!(&in(cx) let callback = self
                .current_animation_frame_list
                .borrow_mut()
                .pop_front()
                .map(|(_, callback)| callback));

            if let Some(ref callback) = *callback {
                // Step 3.3. Invoke callback with « now » and "`report`".
                let _ = callback.Call__(cx, Finite::wrap(*timing), ExceptionHandling::Report);
            }
        }

        self.current_animation_frame_list.borrow_mut().clear();
        self.running_animation_callbacks.set(false);

        if !self.has_animation_frame_callbacks() {
            self.set_animation_frame_callbacks_active(false);
        } else {
            // Acknowledge the consumed worker tick while staying active; Paint
            // will drive the next refresh tick.
            self.send_animation_frame_callbacks_state(true);
        }
    }

    pub(crate) fn clear_animation_frame_callbacks_and_unregister(&self) {
        // Worker shutdown drops pending rAF callbacks and unregisters the tick target.
        let worker_id = self.upcast::<WorkerGlobalScope>().worker_id();
        log::debug!(
            "Clearing dedicated worker animation frame callbacks: worker={worker_id:?} ---->"
        );
        self.animation_frame_list.borrow_mut().clear();
        self.current_animation_frame_list.borrow_mut().clear();
        self.running_animation_callbacks.set(false);
        self.animation_frame_callbacks_active.set(false);
        self.unregister_animation_frame_provider();
    }

    /// The non-None value of the `worker` field can contain a rooted [`TrustedWorkerAddress`]
    /// version of the main thread's worker object. This is set while handling messages and then
    /// unset otherwise, ensuring that the main thread object can be garbage collected. See
    /// [`AutoWorkerReset`].
    fn replace_worker(
        &self,
        new_worker: Option<TrustedWorkerAddress>,
    ) -> Option<TrustedWorkerAddress> {
        let old_worker = std::mem::replace(&mut *self.worker.borrow_mut(), new_worker);

        // The `TaskManager` maintains a handle to this `DedicatedWorkerGlobalScope`'s
        // event_loop_sender, which might in turn have a `TrustedWorkerAddress` rooting of the main
        // thread's worker, which prevents garbage collection. Resetting it here ensures that
        // garbage collection of the main thread object can happen again (assuming the new `worker`
        // is `None`).
        self.upcast::<GlobalScope>()
            .task_manager()
            .set_sender(self.event_loop_sender());

        old_worker
    }

    pub(crate) fn image_cache(&self) -> Arc<dyn ImageCache> {
        self.image_cache.clone()
    }

    pub(crate) fn event_loop_sender(&self) -> Option<ScriptEventLoopSender> {
        Some(ScriptEventLoopSender::DedicatedWorker {
            sender: self.own_sender.clone(),
            main_thread_worker: self.worker.borrow().clone()?,
        })
    }

    pub(crate) fn new_script_pair(&self) -> (ScriptEventLoopSender, ScriptEventLoopReceiver) {
        let (sender, receiver) = unbounded();
        let main_thread_worker = self.worker.borrow().as_ref().unwrap().clone();
        (
            ScriptEventLoopSender::DedicatedWorker {
                sender,
                main_thread_worker,
            },
            ScriptEventLoopReceiver::DedicatedWorker(receiver),
        )
    }

    pub(crate) fn fire_queued_messages(&self, cx: &mut JSContext) {
        let queue: Vec<_> = self.queued_worker_tasks.borrow_mut().drain(..).collect();
        for msg in queue {
            if self.upcast::<WorkerGlobalScope>().is_closing() {
                return;
            }
            self.dispatch_message_event(cx, msg);
        }
    }

    fn dispatch_message_event(&self, cx: &mut JSContext, msg: MessageData) {
        let scope = self.upcast::<WorkerGlobalScope>();
        let target = self.upcast();
        let mut realm = enter_auto_realm(cx, self);
        let cx = &mut realm;
        rooted!(&in(cx) let mut message = UndefinedValue());
        if let Ok(ports) =
            structuredclone::read(cx, scope.upcast(), *msg.data, message.handle_mut())
        {
            MessageEvent::dispatch_jsval(
                cx,
                target,
                scope.upcast(),
                message.handle(),
                Some(msg.origin.ascii_serialization().as_ref()),
                None,
                ports,
            );
        } else {
            MessageEvent::dispatch_error(cx, target, scope.upcast());
        }
    }

    fn handle_script_event(&self, msg: WorkerScriptMsg, cx: &mut JSContext) {
        match msg {
            WorkerScriptMsg::DOMMessage(message_data) => {
                if self.upcast::<WorkerGlobalScope>().is_execution_ready() {
                    self.dispatch_message_event(cx, message_data);
                } else {
                    self.queued_worker_tasks.borrow_mut().push(message_data);
                }
            },
            WorkerScriptMsg::Common(msg) => {
                self.upcast::<WorkerGlobalScope>().process_event(msg, cx);
            },
        }
    }

    /// <https://html.spec.whatwg.org/multipage/#event-loop-processing-model>
    fn handle_mixed_message(&self, msg: MixedMessage, cx: &mut JSContext) -> bool {
        if self.upcast::<WorkerGlobalScope>().is_closing() {
            return false;
        }
        // FIXME(#26324): `self.worker` is None in devtools messages.
        match msg {
            #[cfg(feature = "devtools")]
            MixedMessage::Devtools(msg) => self
                .upcast::<WorkerGlobalScope>()
                .handle_devtools_message(msg, cx),
            MixedMessage::Worker(DedicatedWorkerScriptMsg::CommonWorker(linked_worker, msg)) => {
                let _ar = AutoWorkerReset::new(self, linked_worker);
                self.handle_script_event(msg, cx);
            },
            MixedMessage::Worker(DedicatedWorkerScriptMsg::WakeUp) => {},
            MixedMessage::Control(DedicatedWorkerControlMsg::Exit) => {
                return false;
            },
            MixedMessage::Control(DedicatedWorkerControlMsg::AnimationFrameProviderUnsupported) => {
                self.clear_animation_frame_callbacks_and_unregister();
                self.upcast::<GlobalScope>()
                    .disable_owned_worker_animation_frame_providers();
            },
            MixedMessage::AnimationFrameTick(_) => {
                // Step 6.1.2. Run the animation frame callbacks for that
                // DedicatedWorkerGlobalScope, passing in now as the timestamp.
                self.run_the_animation_frame_callbacks(cx);
            },
            MixedMessage::Timer => {},
        }
        true
    }

    /// Step 7.2 of <https://html.spec.whatwg.org/multipage/#report-an-exception>
    pub(crate) fn forward_error_to_worker_object(&self, error_info: ErrorInfo) {
        // Step 7.2.1. Let workerObject be the Worker object associated with global.
        let worker = self.worker.borrow().as_ref().unwrap().clone();
        let pipeline_id = self.upcast::<GlobalScope>().pipeline_id();
        let task = Box::new(task!(forward_error_to_worker_object: move |cx| {
            let worker = worker.root();
            let global = worker.global();

            // Step 7.2.2. Set notHandled to the result of firing an event named error at workerObject, using ErrorEvent,
            // with the cancelable attribute initialized to true, and additional attributes initialized according to errorInfo.
            let event = ErrorEvent::new(
                cx,
                &global,
                atom!("error"),
                EventBubbles::DoesNotBubble,
                EventCancelable::Cancelable,
                error_info.message.as_str().into(),
                error_info.filename.as_str().into(),
                error_info.lineno,
                error_info.column,
                HandleValue::null(),
            );

            // Step 7.2.3. If notHandled is true, then report exception for workerObject's relevant global object with omitError set to true.
            if event.upcast::<Event>().fire(cx, worker.upcast::<EventTarget>()) {
                global.report_an_error(cx, error_info, HandleValue::null());
            }
        }));
        self.parent_event_loop_sender
            .send(CommonScriptMsg::Task(
                WorkerEvent,
                task,
                Some(pipeline_id),
                TaskSourceName::DOMManipulation,
            ))
            .unwrap();
    }

    /// <https://html.spec.whatwg.org/multipage/#dom-dedicatedworkerglobalscope-postmessage>
    fn post_message_impl(
        &self,
        cx: &mut JSContext,
        message: HandleValue,
        transfer: CustomAutoRooterGuard<Vec<*mut JSObject>>,
    ) -> ErrorResult {
        let data = structuredclone::write(cx, message, Some(transfer))?;
        let worker = self.worker.borrow().as_ref().unwrap().clone();
        let global_scope = self.upcast::<GlobalScope>();
        let pipeline_id = global_scope.pipeline_id();
        let task = Box::new(task!(post_worker_message: move |cx| {
            Worker::handle_message(worker, data, cx);
        }));
        self.parent_event_loop_sender
            .send(CommonScriptMsg::Task(
                WorkerEvent,
                task,
                Some(pipeline_id),
                TaskSourceName::DOMManipulation,
            ))
            .expect("Sending to parent failed");
        Ok(())
    }

    pub(crate) fn browsing_context(&self) -> Option<BrowsingContextId> {
        self.browsing_context
    }

    pub(crate) fn report_csp_violations(&self, violations: Vec<Violation>) {
        let pipeline_id = self.upcast::<GlobalScope>().pipeline_id();
        self.parent_event_loop_sender
            .send(CommonScriptMsg::ReportCspViolations(
                pipeline_id,
                violations,
            ))
            .unwrap_or_else(|error| {
                log::warn!("Failed to send CSP violations to parent event loop: {error}");
            });
    }

    pub(crate) fn forward_simple_error_at_worker(&self) {
        let pipeline_id = self.upcast::<GlobalScope>().pipeline_id();
        let worker = self.worker.borrow().clone().expect("worker must be set");
        self.parent_event_loop_sender
            .send(CommonScriptMsg::Task(
                WorkerEvent,
                Box::new(SimpleWorkerErrorHandler::new(worker)),
                Some(pipeline_id),
                TaskSourceName::DOMManipulation,
            ))
            .expect("Sending to parent failed");
    }
}

/// <https://html.spec.whatwg.org/multipage/#fetch-a-classic-worker-script>
pub(crate) fn fetch_a_classic_worker_script(
    workerscope: &WorkerGlobalScope,
    url_with_blob_lock: UrlWithBlobClaim,
    fetch_client: RequestClient,
    destination: Destination,
    webview_id: Option<WebViewId>,
    referrer: Referrer,
) {
    let policy_container = fetch_client.policy_container.clone();

    // Step 1. Let request be a new request whose URL is url,
    let request = RequestBuilder::new(webview_id, url_with_blob_lock.clone(), referrer)
        // client is fetchClient,
        .client(fetch_client)
        .pipeline_id(Some(workerscope.pipeline_id()))
        // destination is destination,
        .destination(destination)
        // TODO initiator type is "other",
        // mode is "same-origin",
        .mode(RequestMode::SameOrigin)
        // credentials mode is "same-origin",
        .credentials_mode(CredentialsMode::CredentialsSameOrigin)
        // parser metadata is "not parser-inserted",
        .parser_metadata(ParserMetadata::NotParserInserted)
        // and whose use-URL-credentials flag is set.
        .use_url_credentials(true);

    let context = ScriptFetchContext::new(
        Trusted::new(workerscope),
        url_with_blob_lock.url(),
        policy_container,
    );
    let global = workerscope.upcast::<GlobalScope>();
    let task_source = global.task_manager().networking_task_source().to_sendable();
    global.fetch(request, context, task_source);
}

impl DedicatedWorkerGlobalScopeMethods<crate::DomTypeHolder> for DedicatedWorkerGlobalScope {
    /// <https://html.spec.whatwg.org/multipage/#dom-dedicatedworkerglobalscope-name>
    fn Name(&self) -> DOMString {
        self.workerglobalscope.worker_name()
    }

    /// <https://html.spec.whatwg.org/multipage/#dom-dedicatedworkerglobalscope-postmessage>
    fn PostMessage(
        &self,
        cx: &mut JSContext,
        message: HandleValue,
        transfer: CustomAutoRooterGuard<Vec<*mut JSObject>>,
    ) -> ErrorResult {
        self.post_message_impl(cx, message, transfer)
    }

    /// <https://html.spec.whatwg.org/multipage/#dom-dedicatedworkerglobalscope-postmessage>
    fn PostMessage_(
        &self,
        cx: &mut JSContext,
        message: HandleValue,
        options: &StructuredSerializeOptions,
    ) -> ErrorResult {
        auto_root!(&in(cx) let guard =
            options
                .transfer
                .iter()
                .map(|js: &RootedTraceableBox<Heap<*mut JSObject>>| js.get())
                .collect::<Vec<_>>());
        self.post_message_impl(cx, message, guard)
    }

    /// <https://html.spec.whatwg.org/multipage/#dom-dedicatedworkerglobalscope-close>
    fn Close(&self) {
        // Step 2
        self.upcast::<WorkerGlobalScope>().close();
    }

    /// <https://html.spec.whatwg.org/multipage/#dom-animationframeprovider-requestanimationframe>
    fn RequestAnimationFrame(
        &self,
        callback: RootedCallback<FrameRequestCallback>,
    ) -> Fallible<u32> {
        self.request_animation_frame(callback)
    }

    /// <https://html.spec.whatwg.org/multipage/#dom-animationframeprovider-cancelanimationframe>
    fn CancelAnimationFrame(&self, ident: u32) -> ErrorResult {
        self.cancel_animation_frame(ident)
    }

    // https://html.spec.whatwg.org/multipage/#handler-dedicatedworkerglobalscope-onmessage
    event_handler!(message, GetOnmessage, SetOnmessage);

    // https://html.spec.whatwg.org/multipage/#handler-dedicatedworkerglobalscope-onmessageerror
    event_handler!(messageerror, GetOnmessageerror, SetOnmessageerror);
}

impl HasOrigin for DedicatedWorkerGlobalScope {
    fn origin(&self) -> MutableOrigin {
        self.upcast::<WorkerGlobalScope>().origin()
    }
}