script/dom/globalscope/

globalscope.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/. */

use std::borrow::Cow;
use std::cell::{Cell, OnceCell, Ref, RefCell};
use std::collections::hash_map::Entry;
use std::collections::{HashMap, HashSet, VecDeque};
use std::ffi::CStr;
use std::mem;
use std::ops::{Deref, Index};
use std::ptr::NonNull;
use std::rc::Rc;
use std::sync::Arc;
use std::sync::atomic::{AtomicBool, Ordering};
use std::thread::JoinHandle;
use std::time::{Duration, Instant};

use content_security_policy::CspList;
use crossbeam_channel::Sender;
use devtools_traits::{PageError, ScriptToDevtoolsControlMsg, get_time_stamp};
use dom_struct::dom_struct;
use embedder_traits::{
    ConsoleLogLevel, EmbedderMsg, JavaScriptEvaluationError, ScriptToEmbedderChan,
};
use fonts::FontContext;
use indexmap::IndexSet;
use ipc_channel::router::ROUTER;
use js::context::{JSContext, NoGC};
use js::jsapi::{GetNonCCWObjectGlobal, HandleObject, Heap, JSObject};
use js::jsval::UndefinedValue;
use js::panic::maybe_resume_unwind;
use js::realm::CurrentRealm;
use js::rust::wrappers2::{Compile1, CurrentGlobalOrNull};
use js::rust::{
    CustomAutoRooter, CustomAutoRooterGuard, HandleValue, MutableHandleValue, ParentRuntime,
    get_object_class, transform_str_to_source_text,
};
use js::{JSCLASS_IS_DOMJSCLASS, JSCLASS_IS_GLOBAL};
use net_traits::blob_url_store::BlobBuf;
use net_traits::filemanager_thread::{
    FileManagerResult, FileManagerThreadMsg, ReadFileProgress, RelativePos,
};
use net_traits::image_cache::ImageCache;
use net_traits::policy_container::PolicyContainer;
use net_traits::request::{
    InsecureRequestsPolicy, Origin as RequestOrigin, Referrer, RequestBuilder, RequestClient,
};
use net_traits::{
    CoreResourceMsg, CoreResourceThread, ReferrerPolicy, ResourceThreads, fetch_async,
};
use profile_traits::{
    generic_channel as profile_generic_channel, ipc as profile_ipc, mem as profile_mem,
    time as profile_time,
};
use rustc_hash::{FxBuildHasher, FxHashMap};
use script_bindings::callback::OwnerWindow;
use script_bindings::cell::{DomRefCell, RefMut};
use script_bindings::interfaces::GlobalScopeHelpers;
use script_bindings::reflector::DomObject;
use script_bindings::settings_stack::run_a_script;
use servo_base::generic_channel;
use servo_base::generic_channel::{GenericCallback, GenericSend};
use servo_base::id::{
    BlobId, BroadcastChannelRouterId, MessagePortId, MessagePortRouterId, PipelineId,
    ServiceWorkerId, ServiceWorkerRegistrationId, TEST_WEBVIEW_ID, WebViewId,
};
use servo_config::pref;
use servo_constellation_traits::{
    BlobData, BlobImpl, BroadcastChannelMsg, ConstellationInterest, FileBlob, MessagePortImpl,
    MessagePortMsg, PortMessageTask, ScriptToConstellationChan, ScriptToConstellationMessage,
    ScriptToConstellationSender,
};
use servo_url::{ImmutableOrigin, MutableOrigin, ServoUrl};
use storage_traits::StorageThreads;
use strum::VariantArray;
use timers::{TimerEventRequest, TimerId};
use uuid::Uuid;
#[cfg(feature = "webgpu")]
use webgpu_traits::{DeviceLostReason, WebGPUDevice};

use crate::DomTypeHolder;
use crate::dom::bindings::codegen::Bindings::BroadcastChannelBinding::BroadcastChannelMethods;
use crate::dom::bindings::codegen::Bindings::EventSourceBinding::EventSource_Binding::EventSourceMethods;
use crate::dom::bindings::codegen::Bindings::FunctionBinding::Function;
use crate::dom::bindings::codegen::Bindings::MessagePortBinding::StructuredSerializeOptions;
use crate::dom::bindings::codegen::Bindings::NotificationBinding::NotificationPermissionCallback;
use crate::dom::bindings::codegen::Bindings::PermissionStatusBinding::{
    PermissionName, PermissionState,
};
#[cfg(feature = "webgpu")]
use crate::dom::bindings::codegen::Bindings::WebGPUBinding::GPUDeviceLostReason;
use crate::dom::bindings::codegen::Bindings::WindowBinding::WindowMethods;
use crate::dom::bindings::codegen::Bindings::WorkerGlobalScopeBinding::WorkerGlobalScopeMethods;
use crate::dom::bindings::conversions::{root_from_object, root_from_object_static};
#[cfg(feature = "js_backtrace")]
use crate::dom::bindings::error::LAST_EXCEPTION_BACKTRACE;
use crate::dom::bindings::error::{
    Error, ErrorInfo, Fallible, report_pending_exception, take_and_report_pending_exception_for_api,
};
use crate::dom::bindings::frozenarray::CachedFrozenArray;
use crate::dom::bindings::inheritance::Castable;
use crate::dom::bindings::refcounted::{Trusted, TrustedPromise};
use crate::dom::bindings::reflector::DomGlobal;
use crate::dom::bindings::root::{Dom, DomRoot, MutNullableDom};
use crate::dom::bindings::settings_stack::{entry_global, incumbent_global};
use crate::dom::bindings::str::DOMString;
use crate::dom::bindings::structuredclone;
use crate::dom::bindings::trace::{CustomTraceable, HashMapTracedValues, RootedTraceableBox};
use crate::dom::bindings::weakref::{DOMTracker, WeakRef};
use crate::dom::blob::Blob;
use crate::dom::broadcastchannel::BroadcastChannel;
use crate::dom::dedicatedworkerglobalscope::{
    DedicatedWorkerControlMsg, DedicatedWorkerGlobalScope,
};
use crate::dom::dissimilaroriginwindow::DissimilarOriginWindow;
use crate::dom::errorevent::ErrorEvent;
use crate::dom::event::{Event, EventBubbles, EventCancelable};
use crate::dom::eventsource::EventSource;
use crate::dom::eventtarget::EventTarget;
use crate::dom::file::File;
use crate::dom::globalscope::script_execution::{
    ErrorReporting, evaluate_script, fill_compile_options,
};
use crate::dom::idbfactory::IDBFactory;
use crate::dom::messageport::MessagePort;
use crate::dom::paintworkletglobalscope::PaintWorkletGlobalScope;
use crate::dom::performance::performance::Performance;
use crate::dom::performance::performanceentry::EntryType;
use crate::dom::promise::Promise;
use crate::dom::readablestream::{CrossRealmTransformReadable, ReadableStream};
use crate::dom::serviceworker::ServiceWorker;
use crate::dom::serviceworkerglobalscope::ServiceWorkerGlobalScope;
use crate::dom::serviceworkerregistration::ServiceWorkerRegistration;
use crate::dom::sharedworkerglobalscope::SharedWorkerGlobalScope;
use crate::dom::stream::underlyingsourcecontainer::UnderlyingSourceType;
use crate::dom::stream::writablestream::CrossRealmTransformWritable;
use crate::dom::transformstream::CrossRealmTransform;
use crate::dom::types::{AbortSignal, DebuggerGlobalScope, MessageEvent};
#[cfg(feature = "webgpu")]
use crate::dom::webgpu::gpudevice::GPUDevice;
#[cfg(feature = "webgpu")]
use crate::dom::webgpu::identityhub::IdentityHub;
use crate::dom::window::Window;
use crate::dom::workerglobalscope::WorkerGlobalScope;
use crate::dom::workletglobalscope::WorkletGlobalScope;
use crate::fetch::{DeferredFetchRecordId, FetchGroup, QueuedDeferredFetchRecord};
use crate::messaging::{CommonScriptMsg, ScriptEventLoopReceiver, ScriptEventLoopSender};
use crate::microtask::MicrotaskRunnable;
use crate::network_listener::{FetchResponseListener, NetworkListener};
use crate::realms::enter_auto_realm;
use crate::script_module::{
    ImportMap, ModuleRequest, ModuleStatus, ResolvedModule, ScriptFetchOptions,
};
use crate::script_runtime::ThreadSafeJSContext;
use crate::script_thread::{ScriptThread, with_script_thread};
use crate::task_manager::TaskManager;
use crate::task_source::SendableTaskSource;
use crate::timers::{
    IsInterval, OneshotTimerCallback, OneshotTimerHandle, OneshotTimers, TimerCallback,
    TimerEventId, TimerSource,
};
use crate::unminify::unminified_path;

#[derive(JSTraceable, MallocSizeOf)]
pub(crate) struct AutoCloseWorker {
    /// <https://html.spec.whatwg.org/multipage/#dom-workerglobalscope-closing>
    #[conditional_malloc_size_of]
    closing: Arc<AtomicBool>,
    /// A handle to join on the worker thread.
    #[ignore_malloc_size_of = "JoinHandle"]
    join_handle: Option<JoinHandle<()>>,
    /// A sender of control messages,
    /// currently only used to signal shutdown.
    #[no_trace]
    control_sender: Sender<DedicatedWorkerControlMsg>,
    /// The context to request an interrupt on the worker thread.
    #[ignore_malloc_size_of = "mozjs"]
    #[no_trace]
    context: ThreadSafeJSContext,
}

impl Drop for AutoCloseWorker {
    /// <https://html.spec.whatwg.org/multipage/#terminate-a-worker>
    fn drop(&mut self) {
        // Step 1. Set the worker's `WorkerGlobalScope` object's closing flag to true.
        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.");
        }

        self.context.request_interrupt_callback();

        // Step 2. If there are any tasks queued in the `WorkerGlobalScope` object's relevant agent's event loop's task queues, discard them without processing them.
        // Step 3. Abort the script currently running in the worker.
        // Step 4. If the worker's WorkerGlobalScope object is actually a DedicatedWorkerGlobalScope object (i.e. the worker is a dedicated worker), then empty the port message queue of the port that the worker's implicit port is entangled with.
        // TODO Steps 2-4.
        if self
            .join_handle
            .take()
            .expect("No handle to join on worker.")
            .join()
            .is_err()
        {
            warn!("Failed to join on dedicated worker thread.");
        }
    }
}

#[dom_struct]
pub(crate) struct GlobalScope {
    eventtarget: EventTarget,

    /// The message-port router id for this global, if it is managing ports.
    message_port_state: DomRefCell<MessagePortState>,

    /// The broadcast channels state this global, if it is managing any.
    broadcast_channel_state: DomRefCell<BroadcastChannelState>,

    /// Tracks the number of active listeners per constellation interest category.
    /// When the count transitions from 0 to 1, a RegisterInterest message is sent.
    /// When it transitions from 1 to 0, an UnregisterInterest message is sent.
    #[no_trace]
    constellation_interest_counts: RefCell<HashMap<ConstellationInterest, usize>>,

    /// The blobs managed by this global, if any.
    blob_state: DomRefCell<HashMapTracedValues<BlobId, BlobInfo, FxBuildHasher>>,

    /// <https://w3c.github.io/ServiceWorker/#environment-settings-object-service-worker-registration-object-map>
    registration_map: DomRefCell<
        HashMapTracedValues<
            ServiceWorkerRegistrationId,
            Dom<ServiceWorkerRegistration>,
            FxBuildHasher,
        >,
    >,

    /// <https://w3c.github.io/IndexedDB/#factory-interface>
    indexeddb: MutNullableDom<IDBFactory>,

    /// <https://w3c.github.io/ServiceWorker/#environment-settings-object-service-worker-object-map>
    worker_map: DomRefCell<HashMapTracedValues<ServiceWorkerId, Dom<ServiceWorker>, FxBuildHasher>>,

    /// Timers (milliseconds) used by the Console API.
    console_timers: DomRefCell<HashMap<DOMString, Instant>>,

    /// module map is used when importing JavaScript modules
    /// <https://html.spec.whatwg.org/multipage/#concept-settings-object-module-map>
    #[ignore_malloc_size_of = "mozjs"]
    module_map: DomRefCell<HashMapTracedValues<ModuleRequest, ModuleStatus>>,

    /// For providing instructions to an optional devtools server.
    #[no_trace]
    devtools_chan: Option<GenericCallback<ScriptToDevtoolsControlMsg>>,

    /// For sending messages to the memory profiler.
    #[no_trace]
    mem_profiler_chan: profile_mem::ProfilerChan,

    /// For sending messages to the time profiler.
    #[no_trace]
    time_profiler_chan: profile_time::ProfilerChan,

    /// A handle for communicating messages to the constellation thread.
    #[no_trace]
    script_to_constellation_sender: ScriptToConstellationSender,

    /// A handle for communicating messages to the Embedder.
    #[no_trace]
    script_to_embedder_chan: ScriptToEmbedderChan,

    /// <https://html.spec.whatwg.org/multipage/#in-error-reporting-mode>
    in_error_reporting_mode: Cell<bool>,

    /// Associated resource threads for use by DOM objects like XMLHttpRequest,
    /// including resource_thread and filemanager_thread
    #[no_trace]
    resource_threads: ResourceThreads,

    /// Associated resource threads for use by DOM objects like XMLHttpRequest,
    /// including indexeddb thread and storage_thread
    #[no_trace]
    storage_threads: StorageThreads,

    /// <https://html.spec.whatwg.org/multipage/#concept-environment-creation-url>
    #[no_trace]
    creation_url: DomRefCell<ServoUrl>,

    /// <https://html.spec.whatwg.org/multipage/#concept-environment-top-level-creation-url>
    #[no_trace]
    top_level_creation_url: Option<ServoUrl>,

    /// A map for storing the previous permission state read results.
    permission_state_invocation_results: DomRefCell<HashMap<PermissionName, PermissionState>>,

    /// Vector storing closing references of all workers
    list_auto_close_worker: DomRefCell<Vec<AutoCloseWorker>>,

    /// Vector storing references of all eventsources.
    event_source_tracker: DOMTracker<EventSource>,

    /// Dependent AbortSignals that must be kept alive per
    /// <https://dom.spec.whatwg.org/#abort-signal-garbage-collection?
    abort_signal_dependents: DomRefCell<IndexSet<Dom<AbortSignal>>>,

    /// Storage for watching rejected promises waiting for some client to
    /// consume their rejection.
    /// Promises in this list have been rejected in the last turn of the
    /// event loop without the rejection being handled.
    /// Note that this can contain nullptrs in place of promises removed because
    /// they're consumed before it'd be reported.
    ///
    /// <https://html.spec.whatwg.org/multipage/#about-to-be-notified-rejected-promises-list>
    #[ignore_malloc_size_of = "mozjs"]
    // `Heap` values must stay boxed, as they need semantics like `Pin`
    // (that is, they cannot be moved).
    #[allow(clippy::vec_box)]
    uncaught_rejections: DomRefCell<Vec<Box<Heap<*mut JSObject>>>>,

    /// Promises in this list have previously been reported as rejected
    /// (because they were in the above list), but the rejection was handled
    /// in the last turn of the event loop.
    ///
    /// <https://html.spec.whatwg.org/multipage/#outstanding-rejected-promises-weak-set>
    #[ignore_malloc_size_of = "mozjs"]
    // `Heap` values must stay boxed, as they need semantics like `Pin`
    // (that is, they cannot be moved).
    #[allow(clippy::vec_box)]
    consumed_rejections: DomRefCell<Vec<Box<Heap<*mut JSObject>>>>,

    /// Identity Manager for WebGPU resources
    #[ignore_malloc_size_of = "defined in wgpu"]
    #[no_trace]
    #[cfg(feature = "webgpu")]
    gpu_id_hub: Arc<IdentityHub>,

    /// WebGPU devices
    #[cfg(feature = "webgpu")]
    gpu_devices: DomRefCell<HashMapTracedValues<WebGPUDevice, WeakRef<GPUDevice>, FxBuildHasher>>,

    // https://w3c.github.io/performance-timeline/#supportedentrytypes-attribute
    #[ignore_malloc_size_of = "mozjs"]
    frozen_supported_performance_entry_types: CachedFrozenArray,

    /// The stack of active group labels for the Console APIs.
    console_group_stack: DomRefCell<Vec<DOMString>>,

    /// The count map for the Console APIs.
    ///
    /// <https://console.spec.whatwg.org/#count>
    console_count_map: DomRefCell<HashMap<DOMString, usize>>,

    /// Is considered in a secure context
    inherited_secure_context: Option<bool>,

    /// Directory to store unminified scripts for this window if unminify-js
    /// opt is enabled.
    unminified_js_dir: Option<String>,

    /// The byte length queuing strategy size function that will be initialized once
    /// `size` getter of `ByteLengthQueuingStrategy` is called.
    ///
    /// <https://streams.spec.whatwg.org/#byte-length-queuing-strategy-size-function>
    #[ignore_malloc_size_of = "callbacks are hard"]
    byte_length_queuing_strategy_size_function: OnceCell<Rc<Function>>,

    /// The count queuing strategy size function that will be initialized once
    /// `size` getter of `CountQueuingStrategy` is called.
    ///
    /// <https://streams.spec.whatwg.org/#count-queuing-strategy-size-function>
    #[ignore_malloc_size_of = "callbacks are hard"]
    count_queuing_strategy_size_function: OnceCell<Rc<Function>>,

    #[ignore_malloc_size_of = "callbacks are hard"]
    notification_permission_request_callback_map:
        DomRefCell<HashMap<String, Rc<NotificationPermissionCallback>>>,

    /// An import map allows control over module specifier resolution.
    /// For now, only Window global objects have their import map modified from the initial empty one.
    ///
    /// <https://html.spec.whatwg.org/multipage/#import-maps>
    import_map: DomRefCell<ImportMap>,

    /// <https://html.spec.whatwg.org/multipage/#resolved-module-set>
    resolved_module_set: DomRefCell<HashSet<ResolvedModule>>,

    /// The [`FontContext`] for this [`GlobalScope`] if it has one. This is used for
    /// canvas and layout, so if this [`GlobalScope`] doesn't need to use either, this
    /// might be `None`.
    #[conditional_malloc_size_of]
    #[no_trace]
    font_context: Option<Arc<FontContext>>,

    /// <https://fetch.spec.whatwg.org/#environment-settings-object-fetch-group>
    #[no_trace]
    fetch_group: RefCell<FetchGroup>,
}

/// A wrapper for glue-code between the ipc router and the event-loop.
struct MessageListener {
    task_source: SendableTaskSource,
    context: Trusted<GlobalScope>,
}

/// A wrapper for broadcasts coming in over IPC, and the event-loop.
struct BroadcastListener {
    task_source: SendableTaskSource,
    context: Trusted<GlobalScope>,
}

type FileListenerCallback =
    Box<dyn Fn(&mut js::context::JSContext, Rc<Promise>, Fallible<Vec<u8>>) + Send>;

/// A wrapper for the handling of file data received by the ipc router
struct FileListener {
    /// State should progress as either of:
    /// - Some(Empty) => Some(Receiving) => None
    /// - Some(Empty) => None
    state: Option<FileListenerState>,
    task_source: SendableTaskSource,
}

enum FileListenerTarget {
    Promise(TrustedPromise, FileListenerCallback),
    Stream(Trusted<ReadableStream>),
}

enum FileListenerState {
    Empty(FileListenerTarget),
    Receiving(Vec<u8>, FileListenerTarget),
}

#[derive(JSTraceable, MallocSizeOf)]
/// A holder of a weak reference for a DOM blob or file.
pub(crate) enum BlobTracker {
    /// A weak ref to a DOM file.
    File(WeakRef<File>),
    /// A weak ref to a DOM blob.
    Blob(WeakRef<Blob>),
}

#[derive(JSTraceable, MallocSizeOf)]
/// The info pertaining to a blob managed by this global.
pub(crate) struct BlobInfo {
    /// The weak ref to the corresponding DOM object.
    tracker: BlobTracker,
    /// The data and logic backing the DOM object.
    #[no_trace]
    blob_impl: BlobImpl,
    /// Whether this blob has an outstanding URL,
    /// <https://w3c.github.io/FileAPI/#url>.
    has_url: bool,
}

/// The result of looking-up the data for a Blob,
/// containing either the in-memory bytes,
/// or the file-id.
enum BlobResult {
    Bytes(Vec<u8>),
    File(Uuid, usize),
}

/// Data representing a message-port managed by this global.
#[derive(JSTraceable, MallocSizeOf)]
#[cfg_attr(crown, crown::unrooted_must_root_lint::must_root)]
pub(crate) struct ManagedMessagePort {
    /// The DOM port.
    dom_port: Dom<MessagePort>,
    /// The logic and data backing the DOM port.
    /// The option is needed to take out the port-impl
    /// as part of its transferring steps,
    /// without having to worry about rooting the dom-port.
    #[no_trace]
    port_impl: Option<MessagePortImpl>,
    /// We keep ports pending when they are first transfer-received,
    /// and only add them, and ask the constellation to complete the transfer,
    /// in a subsequent task if the port hasn't been re-transfered.
    pending: bool,
    /// Whether the port has been closed by script in this global,
    /// so it can be removed.
    explicitly_closed: bool,
    /// The handler for `message` or `messageerror` used in the cross realm transform,
    /// if any was setup with this port.
    cross_realm_transform: Option<CrossRealmTransform>,
}

/// State representing whether this global is currently managing broadcast channels.
#[derive(JSTraceable, MallocSizeOf)]
#[cfg_attr(crown, crown::unrooted_must_root_lint::must_root)]
pub(crate) enum BroadcastChannelState {
    /// The broadcast-channel router id for this global, and a queue of managed channels.
    /// Step 9, "sort destinations"
    /// of <https://html.spec.whatwg.org/multipage/#dom-broadcastchannel-postmessage>
    /// requires keeping track of creation order, hence the queue.
    Managed(
        #[no_trace] BroadcastChannelRouterId,
        /// The map of channel-name to queue of channels, in order of creation.
        HashMap<DOMString, VecDeque<Dom<BroadcastChannel>>>,
    ),
    /// This global is not managing any broadcast channels at this time.
    UnManaged,
}

/// State representing whether this global is currently managing messageports.
#[derive(JSTraceable, MallocSizeOf)]
#[cfg_attr(crown, crown::unrooted_must_root_lint::must_root)]
pub(crate) enum MessagePortState {
    /// The message-port router id for this global, and a map of managed ports.
    Managed(
        #[no_trace] MessagePortRouterId,
        HashMapTracedValues<MessagePortId, ManagedMessagePort, FxBuildHasher>,
    ),
    /// This global is not managing any ports at this time.
    UnManaged,
}

impl BroadcastListener {
    /// Handle a broadcast coming in over IPC,
    /// by queueing the appropriate task on the relevant event-loop.
    fn handle(&self, event: BroadcastChannelMsg) {
        let context = self.context.clone();

        // Note: strictly speaking we should just queue the message event tasks,
        // not queue a task that then queues more tasks.
        // This however seems to be hard to avoid in the light of the IPC.
        // One can imagine queueing tasks directly,
        // for channels that would be in the same script-thread.
        self.task_source
            .queue(task!(broadcast_message_event: move || {
                let global = context.root();
                // Step 10 of https://html.spec.whatwg.org/multipage/#dom-broadcastchannel-postmessage,
                // For each BroadcastChannel object destination in destinations, queue a task.
                global.broadcast_message_event(event, None);
            }));
    }
}

impl MessageListener {
    /// A new message came in, handle it via a task enqueued on the event-loop.
    /// A task is required, since we are using a trusted globalscope,
    /// and we can only access the root from the event-loop.
    fn notify(&self, msg: MessagePortMsg) {
        match msg {
            MessagePortMsg::CompleteTransfer(ports) => {
                let context = self.context.clone();
                self.task_source.queue(
                    task!(process_complete_transfer: move |cx| {
                        let global = context.root();

                        let router_id = match global.port_router_id() {
                            Some(router_id) => router_id,
                            None => {
                                // If not managing any ports, no transfer can succeed,
                                // so just send back everything.
                                let _ = global.script_to_constellation_chan().send(
                                    ScriptToConstellationMessage::MessagePortTransferResult(None, vec![], ports),
                                );
                                return;
                            }
                        };

                        let mut succeeded = vec![];
                        let mut failed = FxHashMap::default();

                        for (id, info) in ports.into_iter() {
                            if global.is_managing_port(&id) {
                                succeeded.push(id);
                                global.complete_port_transfer(
                                    cx,
                                    id,
                                    info.port_message_queue,
                                    info.disentangled,
                                );
                            } else {
                                failed.insert(id, info);
                            }
                        }
                        let _ = global.script_to_constellation_chan().send(
                            ScriptToConstellationMessage::MessagePortTransferResult(Some(router_id), succeeded, failed),
                        );
                    })
                );
            },
            MessagePortMsg::CompletePendingTransfer(port_id, info) => {
                let context = self.context.clone();
                self.task_source.queue(task!(complete_pending: move |cx| {
                    let global = context.root();
                    global.complete_port_transfer(cx, port_id, info.port_message_queue, info.disentangled);
                }));
            },
            MessagePortMsg::CompleteDisentanglement(port_id) => {
                let context = self.context.clone();
                self.task_source
                    .queue(task!(try_complete_disentanglement: move |cx| {
                        let global = context.root();
                        global.try_complete_disentanglement(cx, port_id);
                    }));
            },
            MessagePortMsg::NewTask(port_id, task) => {
                let context = self.context.clone();
                self.task_source.queue(task!(process_new_task: move |cx| {
                    let global = context.root();
                    global.route_task_to_port(cx, port_id, task);
                }));
            },
        }
    }
}

/// Callback used to enqueue file chunks to streams as part of FileListener.
fn stream_handle_incoming(
    cx: &mut js::context::JSContext,
    stream: &ReadableStream,
    bytes: Fallible<Vec<u8>>,
) {
    match bytes {
        Ok(b) => {
            stream.enqueue_native(cx, b);
        },
        Err(e) => {
            stream.error_native(cx, e);
        },
    }
}

/// Callback used to close streams as part of FileListener.
fn stream_handle_eof(cx: &mut js::context::JSContext, stream: &ReadableStream) {
    stream.controller_close_native(cx);
}

impl FileListener {
    fn handle(&mut self, msg: FileManagerResult<ReadFileProgress>) {
        match msg {
            Ok(ReadFileProgress::Meta(blob_buf)) => match self.state.take() {
                Some(FileListenerState::Empty(target)) => {
                    let bytes = if let FileListenerTarget::Stream(ref trusted_stream) = target {
                        let trusted = trusted_stream.clone();

                        let task = task!(enqueue_stream_chunk: move |cx| {
                            let stream = trusted.root();
                            stream_handle_incoming(cx, &stream, Ok(blob_buf.bytes));
                        });
                        self.task_source.queue(task);

                        Vec::with_capacity(0)
                    } else {
                        blob_buf.bytes
                    };

                    self.state = Some(FileListenerState::Receiving(bytes, target));
                },
                _ => panic!(
                    "Unexpected FileListenerState when receiving ReadFileProgress::Meta msg."
                ),
            },
            Ok(ReadFileProgress::Partial(mut bytes_in)) => match self.state.take() {
                Some(FileListenerState::Receiving(mut bytes, target)) => {
                    if let FileListenerTarget::Stream(ref trusted_stream) = target {
                        let trusted = trusted_stream.clone();

                        let task = task!(enqueue_stream_chunk: move |cx| {
                            let stream = trusted.root();
                            stream_handle_incoming(cx, &stream, Ok(bytes_in));
                        });

                        self.task_source.queue(task);
                    } else {
                        bytes.append(&mut bytes_in);
                    };

                    self.state = Some(FileListenerState::Receiving(bytes, target));
                },
                _ => panic!(
                    "Unexpected FileListenerState when receiving ReadFileProgress::Partial msg."
                ),
            },
            Ok(ReadFileProgress::EOF) => match self.state.take() {
                Some(FileListenerState::Receiving(bytes, target)) => match target {
                    FileListenerTarget::Promise(trusted_promise, callback) => {
                        let task = task!(resolve_promise: move |cx| {
                            let promise = trusted_promise.root();
                            let mut realm = enter_auto_realm(cx, &*promise.global());
                            callback(&mut realm, promise, Ok(bytes));
                        });

                        self.task_source.queue(task);
                    },
                    FileListenerTarget::Stream(trusted_stream) => {
                        let task = task!(enqueue_stream_chunk: move |cx| {
                            let stream = trusted_stream.root();
                            stream_handle_eof(cx, &stream);
                        });

                        self.task_source.queue(task);
                    },
                },
                _ => {
                    panic!("Unexpected FileListenerState when receiving ReadFileProgress::EOF msg.")
                },
            },
            Err(_) => match self.state.take() {
                Some(FileListenerState::Receiving(_, target)) |
                Some(FileListenerState::Empty(target)) => {
                    let error = Err(Error::Network(None));

                    match target {
                        FileListenerTarget::Promise(trusted_promise, callback) => {
                            self.task_source.queue(task!(reject_promise: move |cx| {
                                let promise = trusted_promise.root();
                                let mut realm = enter_auto_realm(cx, &*promise.global());
                                callback(&mut realm, promise, error);
                            }));
                        },
                        FileListenerTarget::Stream(trusted_stream) => {
                            self.task_source.queue(task!(error_stream: move |cx| {
                                let stream = trusted_stream.root();
                                stream_handle_incoming(cx, &stream, error);
                            }));
                        },
                    }
                },
                _ => panic!("Unexpected FileListenerState when receiving Err msg."),
            },
        }
    }
}

impl GlobalScope {
    /// <https://storage.spec.whatwg.org/#obtain-a-storage-key-for-non-storage-purposes>
    pub(crate) fn obtain_storage_key_for_non_storage_purposes(&self) -> ImmutableOrigin {
        // Step 1: Let origin be environment’s origin if environment is an environment settings object; otherwise environment’s creation URL’s origin.
        // Step 2: Return a tuple consisting of origin.
        self.origin().immutable().clone()
    }

    /// <https://storage.spec.whatwg.org/#obtain-a-storage-key>
    pub(crate) fn obtain_storage_key(&self) -> Option<ImmutableOrigin> {
        // Step 1: Let key be the result of running obtain a storage key for non-storage purposes
        // with environment.
        let key = self.obtain_storage_key_for_non_storage_purposes();

        // Step 2: If key's origin is an opaque origin, then return failure.
        if let ImmutableOrigin::Opaque(_) = key {
            return None;
        }

        // Step 3: If the user has disabled storage, then return failure.
        if !pref!(dom_indexeddb_enabled) {
            return None;
        }

        // Step 4: Return key.
        Some(key)
    }

    /// A sender to the event loop of this global scope. This either sends to the Worker event loop
    /// or the ScriptThread event loop in the case of a `Window`. This can be `None` for dedicated
    /// workers that are not currently handling a message.
    pub(crate) fn webview_id(&self) -> Option<WebViewId> {
        if let Some(window) = self.downcast::<Window>() {
            return Some(window.webview_id());
        }
        if let Some(worker) = self.downcast::<DedicatedWorkerGlobalScope>() {
            return Some(worker.webview_id());
        }
        if let Some(worker) = self.downcast::<SharedWorkerGlobalScope>() {
            return Some(worker.webview_id());
        }
        // TODO: This should only return None for ServiceWorkerGlobalScope.
        None
    }

    #[allow(clippy::too_many_arguments)]
    pub(crate) fn new_inherited(
        devtools_chan: Option<GenericCallback<ScriptToDevtoolsControlMsg>>,
        mem_profiler_chan: profile_mem::ProfilerChan,
        time_profiler_chan: profile_time::ProfilerChan,
        script_to_constellation_sender: ScriptToConstellationSender,
        script_to_embedder_chan: ScriptToEmbedderChan,
        resource_threads: ResourceThreads,
        storage_threads: StorageThreads,
        creation_url: ServoUrl,
        top_level_creation_url: Option<ServoUrl>,
        #[cfg(feature = "webgpu")] gpu_id_hub: Arc<IdentityHub>,
        inherited_secure_context: Option<bool>,
        unminify_js: bool,
        font_context: Option<Arc<FontContext>>,
    ) -> Self {
        Self {
            message_port_state: DomRefCell::new(MessagePortState::UnManaged),
            broadcast_channel_state: DomRefCell::new(BroadcastChannelState::UnManaged),
            constellation_interest_counts: RefCell::new(HashMap::new()),
            blob_state: Default::default(),
            eventtarget: EventTarget::new_inherited(),
            registration_map: DomRefCell::new(HashMapTracedValues::new_fx()),
            indexeddb: Default::default(),
            worker_map: DomRefCell::new(HashMapTracedValues::new_fx()),
            console_timers: DomRefCell::new(Default::default()),
            module_map: DomRefCell::new(Default::default()),
            devtools_chan,
            mem_profiler_chan,
            time_profiler_chan,
            script_to_constellation_sender,
            script_to_embedder_chan,
            in_error_reporting_mode: Default::default(),
            resource_threads,
            storage_threads,
            creation_url: DomRefCell::new(creation_url),
            top_level_creation_url,
            permission_state_invocation_results: Default::default(),
            list_auto_close_worker: Default::default(),
            event_source_tracker: DOMTracker::new(),
            abort_signal_dependents: Default::default(),
            uncaught_rejections: Default::default(),
            consumed_rejections: Default::default(),
            #[cfg(feature = "webgpu")]
            gpu_id_hub,
            #[cfg(feature = "webgpu")]
            gpu_devices: DomRefCell::new(HashMapTracedValues::new_fx()),
            frozen_supported_performance_entry_types: CachedFrozenArray::new(),
            console_group_stack: DomRefCell::new(Vec::new()),
            console_count_map: Default::default(),
            inherited_secure_context,
            unminified_js_dir: unminify_js.then(|| unminified_path("unminified-js")),
            byte_length_queuing_strategy_size_function: OnceCell::new(),
            count_queuing_strategy_size_function: OnceCell::new(),
            notification_permission_request_callback_map: Default::default(),
            import_map: Default::default(),
            resolved_module_set: Default::default(),
            font_context,
            fetch_group: Default::default(),
        }
    }

    /// The message-port router Id of the global, if any
    fn port_router_id(&self) -> Option<MessagePortRouterId> {
        if let MessagePortState::Managed(id, _message_ports) = &*self.message_port_state.borrow() {
            Some(*id)
        } else {
            None
        }
    }

    /// Is this global managing a given port?
    fn is_managing_port(&self, port_id: &MessagePortId) -> bool {
        if let MessagePortState::Managed(_router_id, message_ports) =
            &*self.message_port_state.borrow()
        {
            return message_ports.contains_key(port_id);
        }
        false
    }

    fn with_timers<T>(&self, f: impl FnOnce(&OneshotTimers) -> T) -> T {
        if let Some(worker) = self.downcast::<WorkerGlobalScope>() {
            f(worker.timers())
        } else if let Some(window) = self.downcast::<Window>() {
            window.with_timers(f)
        } else {
            unreachable!("Unsupported global type retrieving timers")
        }
    }

    pub(crate) fn font_context(&self) -> Option<&Arc<FontContext>> {
        self.font_context.as_ref()
    }

    /// <https://w3c.github.io/ServiceWorker/#get-the-service-worker-registration-object>
    #[allow(clippy::too_many_arguments)]
    pub(crate) fn get_serviceworker_registration(
        &self,
        cx: &mut js::context::JSContext,
        script_url: &ServoUrl,
        scope: &ServoUrl,
        registration_id: ServiceWorkerRegistrationId,
        installing_worker: Option<ServiceWorkerId>,
        _waiting_worker: Option<ServiceWorkerId>,
        _active_worker: Option<ServiceWorkerId>,
    ) -> DomRoot<ServiceWorkerRegistration> {
        // Step 1
        {
            let registrations = self.registration_map.borrow_mut();

            if let Some(registration) = registrations.get(&registration_id) {
                // Step 3
                return DomRoot::from_ref(&**registration);
            }
        }

        // Step 2.1 -> 2.5
        let new_registration =
            ServiceWorkerRegistration::new(cx, self, scope.clone(), registration_id);

        // Step 2.6
        if let Some(worker_id) = installing_worker {
            let worker = self.get_serviceworker(cx, script_url, scope, worker_id);
            new_registration.set_installing(&worker);
        }

        // TODO: 2.7 (waiting worker)

        // TODO: 2.8 (active worker)

        // Step 2.9
        self.registration_map
            .borrow_mut()
            .insert(registration_id, Dom::from_ref(&*new_registration));

        // Step 3
        new_registration
    }

    /// <https://w3c.github.io/ServiceWorker/#get-the-service-worker-object>
    pub(crate) fn get_serviceworker(
        &self,
        cx: &mut js::context::JSContext,
        script_url: &ServoUrl,
        scope: &ServoUrl,
        worker_id: ServiceWorkerId,
    ) -> DomRoot<ServiceWorker> {
        // Step 1
        {
            let workers = self.worker_map.borrow_mut();

            if let Some(worker) = workers.get(&worker_id) {
                // Step 3
                return DomRoot::from_ref(&**worker);
            }
        }

        // Step 2.1
        // TODO: step 2.2, worker state.
        let new_worker = ServiceWorker::new(cx, self, script_url.clone(), scope.clone(), worker_id);

        // Step 2.3
        self.worker_map
            .borrow_mut()
            .insert(worker_id, Dom::from_ref(&*new_worker));

        // Step 3
        new_worker
    }

    /// Complete the transfer of a message-port.
    fn complete_port_transfer(
        &self,
        cx: &mut js::context::JSContext,
        port_id: MessagePortId,
        tasks: VecDeque<PortMessageTask>,
        disentangled: bool,
    ) {
        let should_start = if let MessagePortState::Managed(_id, message_ports) =
            &mut *self.message_port_state.borrow_mut()
        {
            match message_ports.get_mut(&port_id) {
                None => {
                    panic!("complete_port_transfer called for an unknown port.");
                },
                Some(managed_port) => {
                    if managed_port.pending {
                        panic!("CompleteTransfer msg received for a pending port.");
                    }
                    if let Some(port_impl) = managed_port.port_impl.as_mut() {
                        port_impl.complete_transfer(tasks);
                        if disentangled {
                            port_impl.disentangle();
                            managed_port.dom_port.disentangle();
                        }
                        port_impl.enabled()
                    } else {
                        panic!("managed-port has no port-impl.");
                    }
                },
            }
        } else {
            panic!("complete_port_transfer called for an unknown port.");
        };
        if should_start {
            self.start_message_port(cx, &port_id);
        }
    }

    /// The closing of `otherPort`, if it is in a different global.
    /// <https://html.spec.whatwg.org/multipage/#disentangle>
    fn try_complete_disentanglement(
        &self,
        cx: &mut js::context::JSContext,
        port_id: MessagePortId,
    ) {
        let dom_port = if let MessagePortState::Managed(_id, message_ports) =
            &mut *self.message_port_state.borrow_mut()
        {
            if let Some(managed_port) = message_ports.get_mut(&port_id) {
                if managed_port.pending {
                    unreachable!("CompleteDisentanglement msg received for a pending port.");
                }
                let port_impl = managed_port
                    .port_impl
                    .as_mut()
                    .expect("managed-port has no port-impl.");
                port_impl.disentangle();
                managed_port.dom_port.as_rooted()
            } else {
                // Note: this, and the other return below,
                // can happen if the port has already been transferred out of this global,
                // in which case the disentanglement will complete along with the transfer.
                return;
            }
        } else {
            return;
        };

        // Fire an event named close at otherPort.
        dom_port.upcast().fire_event(cx, atom!("close"));

        let res = self.script_to_constellation_chan().send(
            ScriptToConstellationMessage::DisentanglePorts(port_id, None),
        );
        if res.is_err() {
            warn!("Sending DisentanglePorts failed");
        }
    }

    /// Clean-up DOM related resources
    pub(crate) fn perform_a_dom_garbage_collection_checkpoint(&self) {
        self.perform_a_message_port_garbage_collection_checkpoint();
        self.perform_a_blob_garbage_collection_checkpoint();
        self.perform_a_broadcast_channel_garbage_collection_checkpoint();
        self.perform_an_abort_signal_garbage_collection_checkpoint();
    }

    /// Remove the routers for ports and broadcast-channels.
    /// Drain the list of workers.
    pub(crate) fn remove_web_messaging_and_dedicated_workers_infra(&self) {
        self.remove_message_ports_router();
        self.remove_broadcast_channel_router();

        // Drop each ref to a worker explicitly now,
        // which will send a shutdown signal,
        // and join on the worker thread.
        self.list_auto_close_worker
            .borrow_mut()
            .drain(0..)
            .for_each(drop);
    }

    /// Update our state to un-managed,
    /// and tell the constellation to drop the sender to our message-port router.
    fn remove_message_ports_router(&self) {
        if let MessagePortState::Managed(router_id, _message_ports) =
            &*self.message_port_state.borrow()
        {
            let _ = self.script_to_constellation_chan().send(
                ScriptToConstellationMessage::RemoveMessagePortRouter(*router_id),
            );
        }
        *self.message_port_state.borrow_mut() = MessagePortState::UnManaged;
    }

    /// Update our state to un-managed,
    /// and tell the constellation to drop the sender to our broadcast router.
    fn remove_broadcast_channel_router(&self) {
        if let BroadcastChannelState::Managed(router_id, _channels) =
            &*self.broadcast_channel_state.borrow()
        {
            let _ = self.script_to_constellation_chan().send(
                ScriptToConstellationMessage::RemoveBroadcastChannelRouter(
                    *router_id,
                    self.origin().immutable().clone(),
                ),
            );
        }
        *self.broadcast_channel_state.borrow_mut() = BroadcastChannelState::UnManaged;
    }

    /// <https://html.spec.whatwg.org/multipage/#disentangle>
    pub(crate) fn disentangle_port(&self, cx: &mut js::context::JSContext, port: &MessagePort) {
        let initiator_port = port.message_port_id();
        // Let otherPort be the MessagePort which initiatorPort was entangled with.
        let Some(other_port) = port.disentangle() else {
            // Assert: otherPort exists.
            // Note: ignoring the assert,
            // because the streams spec seems to disentangle ports that are disentangled already.
            return;
        };

        // Disentangle initiatorPort and otherPort, so that they are no longer entangled or associated with each other.
        // Note: this is done in part here, and in part at the constellation(if otherPort is in another global).
        let dom_port = if let MessagePortState::Managed(_id, message_ports) =
            &mut *self.message_port_state.borrow_mut()
        {
            let mut dom_port = None;
            for port_id in &[initiator_port, &other_port] {
                match message_ports.get_mut(port_id) {
                    None => {
                        continue;
                    },
                    Some(managed_port) => {
                        let port_impl = managed_port
                            .port_impl
                            .as_mut()
                            .expect("managed-port has no port-impl.");
                        managed_port.dom_port.disentangle();
                        port_impl.disentangle();

                        if **port_id == other_port {
                            dom_port = Some(managed_port.dom_port.as_rooted())
                        }
                    },
                }
            }
            dom_port
        } else {
            panic!("disentangle_port called on a global not managing any ports.");
        };

        // Fire an event named close at `otherPort`.
        // Note: done here if the port is managed by the same global as `initialPort`.
        if let Some(dom_port) = dom_port {
            dom_port.upcast().fire_event(cx, atom!("close"));
        }

        let chan = self.script_to_constellation_chan();
        let initiator_port = *initiator_port;
        self.task_manager()
            .port_message_queue()
            .queue(task!(post_message: move || {
                // Note: we do this in a task to ensure it doesn't affect messages that are still to be routed,
                // see the task queueing in `post_messageport_msg`.
                let res = chan.send(ScriptToConstellationMessage::DisentanglePorts(initiator_port, Some(other_port)));
                if res.is_err() {
                    warn!("Sending DisentanglePorts failed");
                }
            }));
    }

    /// <https://html.spec.whatwg.org/multipage/#entangle>
    pub(crate) fn entangle_ports(&self, port1: MessagePortId, port2: MessagePortId) {
        if let MessagePortState::Managed(_id, message_ports) =
            &mut *self.message_port_state.borrow_mut()
        {
            for (port_id, entangled_id) in &[(port1, port2), (port2, port1)] {
                match message_ports.get_mut(port_id) {
                    None => {
                        return warn!("entangled_ports called on a global not managing the port.");
                    },
                    Some(managed_port) => {
                        if let Some(port_impl) = managed_port.port_impl.as_mut() {
                            managed_port.dom_port.entangle(*entangled_id);
                            port_impl.entangle(*entangled_id);
                        } else {
                            panic!("managed-port has no port-impl.");
                        }
                    },
                }
            }
        } else {
            panic!("entangled_ports called on a global not managing any ports.");
        }

        let _ = self
            .script_to_constellation_chan()
            .send(ScriptToConstellationMessage::EntanglePorts(port1, port2));
    }

    /// Handle the transfer of a port in the current task.
    pub(crate) fn mark_port_as_transferred(&self, port_id: &MessagePortId) -> MessagePortImpl {
        if let MessagePortState::Managed(_id, message_ports) =
            &mut *self.message_port_state.borrow_mut()
        {
            let mut port_impl = message_ports
                .remove(port_id)
                .map(|ref mut managed_port| {
                    managed_port
                        .port_impl
                        .take()
                        .expect("Managed port doesn't have a port-impl.")
                })
                .expect("mark_port_as_transferred called on a global not managing the port.");
            port_impl.set_has_been_shipped();
            let _ = self
                .script_to_constellation_chan()
                .send(ScriptToConstellationMessage::MessagePortShipped(*port_id));
            port_impl
        } else {
            panic!("mark_port_as_transferred called on a global not managing any ports.");
        }
    }

    /// <https://html.spec.whatwg.org/multipage/#dom-messageport-start>
    pub(crate) fn start_message_port(
        &self,
        cx: &mut js::context::JSContext,
        port_id: &MessagePortId,
    ) {
        let (message_buffer, dom_port) = if let MessagePortState::Managed(_id, message_ports) =
            &mut *self.message_port_state.borrow_mut()
        {
            let (message_buffer, dom_port) = match message_ports.get_mut(port_id) {
                None => panic!("start_message_port called on a unknown port."),
                Some(managed_port) => {
                    if let Some(port_impl) = managed_port.port_impl.as_mut() {
                        (port_impl.start(), managed_port.dom_port.as_rooted())
                    } else {
                        panic!("managed-port has no port-impl.");
                    }
                },
            };
            (message_buffer, dom_port)
        } else {
            return warn!("start_message_port called on a global not managing any ports.");
        };
        if let Some(message_buffer) = message_buffer {
            for task in message_buffer {
                self.route_task_to_port(cx, *port_id, task);
            }
            if dom_port.disentangled() {
                // <https://html.spec.whatwg.org/multipage/#disentangle>
                // Fire an event named close at otherPort.
                dom_port.upcast().fire_event(cx, atom!("close"));

                let res = self.script_to_constellation_chan().send(
                    ScriptToConstellationMessage::DisentanglePorts(*port_id, None),
                );
                if res.is_err() {
                    warn!("Sending DisentanglePorts failed");
                }
            }
        }
    }

    /// <https://html.spec.whatwg.org/multipage/#dom-messageport-close>
    pub(crate) fn close_message_port(&self, port_id: &MessagePortId) {
        if let MessagePortState::Managed(_id, message_ports) =
            &mut *self.message_port_state.borrow_mut()
        {
            match message_ports.get_mut(port_id) {
                None => panic!("close_message_port called on an unknown port."),
                Some(managed_port) => {
                    if let Some(port_impl) = managed_port.port_impl.as_mut() {
                        port_impl.close();
                        managed_port.explicitly_closed = true;
                    } else {
                        panic!("managed-port has no port-impl.");
                    }
                },
            };
        } else {
            warn!("close_message_port called on a global not managing any ports.")
        }
    }

    /// <https://html.spec.whatwg.org/multipage/#message-port-post-message-steps>
    // Steps 6 and 7
    pub(crate) fn post_messageport_msg(&self, port_id: MessagePortId, task: PortMessageTask) {
        if let MessagePortState::Managed(_id, message_ports) =
            &mut *self.message_port_state.borrow_mut()
        {
            let entangled_port = match message_ports.get_mut(&port_id) {
                None => panic!("post_messageport_msg called on an unknown port."),
                Some(managed_port) => {
                    if let Some(port_impl) = managed_port.port_impl.as_mut() {
                        port_impl.entangled_port_id()
                    } else {
                        panic!("managed-port has no port-impl.");
                    }
                },
            };
            if let Some(entangled_id) = entangled_port {
                // Step 7
                let this = Trusted::new(self);
                self.task_manager()
                    .port_message_queue()
                    .queue(task!(post_message: move |cx| {
                        let global = this.root();
                        // Note: we do this in a task, as this will ensure the global and constellation
                        // are aware of any transfer that might still take place in the current task.
                        global.route_task_to_port(cx, entangled_id, task);
                    }));
            }
        } else {
            warn!("post_messageport_msg called on a global not managing any ports.");
        }
    }

    /// If we don't know about the port,
    /// send the message to the constellation for routing.
    fn re_route_port_task(&self, port_id: MessagePortId, task: PortMessageTask) {
        let _ = self.script_to_constellation_chan().send(
            ScriptToConstellationMessage::RerouteMessagePort(port_id, task),
        );
    }

    /// <https://html.spec.whatwg.org/multipage/#dom-broadcastchannel-postmessage>
    /// Step 7 and following steps.
    pub(crate) fn schedule_broadcast(&self, msg: BroadcastChannelMsg, channel_id: &Uuid) {
        // First, broadcast locally.
        self.broadcast_message_event(msg.clone(), Some(channel_id));

        if let BroadcastChannelState::Managed(router_id, _) =
            &*self.broadcast_channel_state.borrow()
        {
            // Second, broadcast to other globals via the constellation.
            //
            // Note: for globals in the same script-thread,
            // we could skip the hop to the constellation.
            let _ = self.script_to_constellation_chan().send(
                ScriptToConstellationMessage::ScheduleBroadcast(*router_id, msg),
            );
        } else {
            panic!("Attemps to broadcast a message via global not managing any channels.");
        }
    }

    /// <https://html.spec.whatwg.org/multipage/#dom-broadcastchannel-postmessage>
    /// Step 7 and following steps.
    pub(crate) fn broadcast_message_event(
        &self,
        event: BroadcastChannelMsg,
        channel_id: Option<&Uuid>,
    ) {
        let BroadcastChannelState::Managed(_, channels) = &*self.broadcast_channel_state.borrow()
        else {
            return;
        };

        let BroadcastChannelMsg {
            data,
            origin,
            channel_name,
        } = event;

        // Step 7, a few preliminary steps.

        // - Check the worker is not closing.
        if let Some(worker) = self.downcast::<WorkerGlobalScope>() &&
            worker.is_closing()
        {
            return;
        }

        // - Check the associated document is fully-active.
        if let Some(window) = self.downcast::<Window>() &&
            !window.Document().is_fully_active()
        {
            return;
        }

        // - Check for a case-sensitive match for the name of the channel.
        let Some(channels) = channels.get(&channel_name.into()) else {
            return;
        };
        channels
            .iter()
            .filter(|channel| {
                // Step 8.
                // Filter out the sender.
                if let Some(id) = channel_id {
                    channel.id() != id
                } else {
                    true
                }
            })
            .map(|channel| DomRoot::from_ref(&**channel))
            // Step 9, sort by creation order,
            // done by using a queue to store channels in creation order.
            .for_each(|channel| {
                let data = data.clone_for_broadcast();
                let origin = origin.clone();

                // Step 10: Queue a task on the DOM manipulation task-source,
                // to fire the message event
                let channel = Trusted::new(&*channel);
                let global = Trusted::new(self);
                self.task_manager().dom_manipulation_task_source().queue(
                    task!(process_pending_port_messages: move |cx| {
                        let destination = channel.root();
                        let global = global.root();

                        // 10.1 Check for closed flag.
                        if destination.closed() {
                            return;
                        }

                        rooted!(&in(cx) let mut message = UndefinedValue());

                        // Step 10.3 StructuredDeserialize(serialized, targetRealm).
                        if let Ok(ports) = structuredclone::read(cx, &global, data, message.handle_mut()) {
                            // Step 10.4, Fire an event named message at destination.
                            MessageEvent::dispatch_jsval(
                                cx,
                                destination.upcast(),
                                &global,
                                message.handle(),
                                Some(&origin.ascii_serialization()),
                                None,
                                ports,
                            );
                        } else {
                            // Step 10.3, fire an event named messageerror at destination.
                            MessageEvent::dispatch_error(cx, destination.upcast(), &global);
                        }
                    })
                );
            });
    }

    /// <https://html.spec.whatwg.org/multipage/#encoding-parsing-a-url>
    pub(crate) fn encoding_parse_a_url(&self, url: &str) -> Result<ServoUrl, url::ParseError> {
        if let Some(window) = self.downcast::<Window>() {
            return window.Document().encoding_parse_a_url(url);
        }

        // encoding parsing for worker environments.
        let base = self.api_base_url();
        base.join(url)
    }

    /// <https://streams.spec.whatwg.org/#abstract-opdef-setupcrossrealmtransformreadable>
    /// The "Add a handler for port’s message event with the following steps:"
    /// and "Add a handler for port’s messageerror event with the following steps:" part.
    pub(crate) fn note_cross_realm_transform_readable(
        &self,
        cross_realm_transform_readable: &CrossRealmTransformReadable,
        port_id: &MessagePortId,
    ) {
        let MessagePortState::Managed(_id, message_ports) =
            &mut *self.message_port_state.borrow_mut()
        else {
            unreachable!(
                "Cross realm transform readable must be called on a global managing ports"
            );
        };

        let Some(managed_port) = message_ports.get_mut(port_id) else {
            unreachable!("Cross realm transform readable must match a managed port");
        };

        managed_port.cross_realm_transform = Some(CrossRealmTransform::Readable(
            cross_realm_transform_readable.clone(),
        ));
    }

    /// <https://streams.spec.whatwg.org/#abstract-opdef-setupcrossrealmtransformwritable>
    /// The "Add a handler for port’s message event with the following steps:"
    /// and "Add a handler for port’s messageerror event with the following steps:" part.
    pub(crate) fn note_cross_realm_transform_writable(
        &self,
        cross_realm_transform_writable: &CrossRealmTransformWritable,
        port_id: &MessagePortId,
    ) {
        let MessagePortState::Managed(_id, message_ports) =
            &mut *self.message_port_state.borrow_mut()
        else {
            unreachable!(
                "Cross realm transform writable must be called on a global managing ports"
            );
        };

        let Some(managed_port) = message_ports.get_mut(port_id) else {
            unreachable!("Cross realm transform writable must match a managed port");
        };

        managed_port.cross_realm_transform = Some(CrossRealmTransform::Writable(
            cross_realm_transform_writable.clone(),
        ));
    }

    /// Custom routing logic, followed by the task steps of
    /// <https://html.spec.whatwg.org/multipage/#message-port-post-message-steps>
    fn route_task_to_port(
        &self,
        cx: &mut js::context::JSContext,
        port_id: MessagePortId,
        task: PortMessageTask,
    ) {
        rooted!(&in(cx) let mut cross_realm_transform = None);

        let should_dispatch = if let MessagePortState::Managed(_id, message_ports) =
            &mut *self.message_port_state.borrow_mut()
        {
            if !message_ports.contains_key(&port_id) {
                self.re_route_port_task(port_id, task);
                return;
            }
            match message_ports.get_mut(&port_id) {
                None => panic!("route_task_to_port called for an unknown port."),
                Some(managed_port) => {
                    // If the port is not enabled yet, or if is awaiting the completion of it's transfer,
                    // the task will be buffered and dispatched upon enablement or completion of the transfer.
                    if let Some(port_impl) = managed_port.port_impl.as_mut() {
                        let to_dispatch = port_impl.handle_incoming(task).map(|to_dispatch| {
                            (DomRoot::from_ref(&*managed_port.dom_port), to_dispatch)
                        });
                        cross_realm_transform.set(managed_port.cross_realm_transform.clone());
                        to_dispatch
                    } else {
                        panic!("managed-port has no port-impl.");
                    }
                },
            }
        } else {
            self.re_route_port_task(port_id, task);
            return;
        };

        // Add a task that runs the following steps to the port message queue of targetPort:
        // Note: we are in the task, and running the relevant steps.

        // Let finalTargetPort be the MessagePort in whose port message queue the task now finds itself.
        if let Some((dom_port, PortMessageTask { origin, data })) = should_dispatch {
            // Let messageEventTarget be finalTargetPort's message event target.
            let message_event_target = dom_port.upcast();

            // Let targetRealm be finalTargetPort's relevant realm.
            // Done via the routing logic here and in the constellation: `self` is the target realm.

            // Let messageClone be deserializeRecord.[[Deserialized]].
            // Re-ordered because we need to pass it to `structuredclone::read`.
            rooted!(&in(cx) let mut message_clone = UndefinedValue());

            let mut realm = enter_auto_realm(cx, self);
            let cx = &mut realm.current_realm();

            // Note: this is necessary, on top of entering the realm above,
            // for the call to `GlobalScope::incumbent`,
            // in `MessagePort::post_message_impl` to succeed.
            run_a_script::<DomTypeHolder, _, _>(cx, self, |cx| {
                // Let deserializeRecord be StructuredDeserializeWithTransfer(serializeWithTransferResult, targetRealm).
                // Let newPorts be a new frozen array
                // consisting of all MessagePort objects in deserializeRecord.[[TransferredValues]],
                // if any, maintaining their relative order.
                // Note: both done in `structuredclone::read`.
                if let Ok(ports) = structuredclone::read(cx, self, data, message_clone.handle_mut())
                {
                    // Note: if this port is used to transfer a stream, we handle the events in Rust.
                    if let Some(transform) = cross_realm_transform.deref().as_ref() {
                        match transform {
                            // Add a handler for port’s message event with the following steps:
                            // from <https://streams.spec.whatwg.org/#abstract-opdef-setupcrossrealmtransformreadable>
                            CrossRealmTransform::Readable(readable) => {
                                readable.handle_message(
                                    cx,
                                    self,
                                    &dom_port,
                                    message_clone.handle(),
                                );
                            },
                            // Add a handler for port’s message event with the following steps:
                            // from <https://streams.spec.whatwg.org/#abstract-opdef-setupcrossrealmtransformwritable>
                            CrossRealmTransform::Writable(writable) => {
                                writable.handle_message(cx, self, message_clone.handle());
                            },
                        }
                    } else {
                        // Fire an event named message at messageEventTarget,
                        // using MessageEvent,
                        // with the data attribute initialized to messageClone
                        // and the ports attribute initialized to newPorts.
                        MessageEvent::dispatch_jsval(
                            cx,
                            message_event_target,
                            self,
                            message_clone.handle(),
                            Some(&origin.ascii_serialization()),
                            None,
                            ports,
                        );
                    }
                } else if let Some(transform) = cross_realm_transform.deref().as_ref() {
                    match transform {
                        // Add a handler for port’s messageerror event with the following steps:
                        // from <https://streams.spec.whatwg.org/#abstract-opdef-setupcrossrealmtransformreadable>
                        CrossRealmTransform::Readable(readable) => {
                            readable.handle_error(cx, self, &dom_port);
                        },
                        // Add a handler for port’s messageerror event with the following steps:
                        // from <https://streams.spec.whatwg.org/#abstract-opdef-setupcrossrealmtransformwritable>
                        CrossRealmTransform::Writable(writable) => {
                            writable.handle_error(cx, self, &dom_port);
                        },
                    }
                } else {
                    // If this throws an exception, catch it,
                    // fire an event named messageerror at messageEventTarget,
                    // using MessageEvent, and then return.
                    MessageEvent::dispatch_error(cx, message_event_target, self);
                }
            });
        }
    }

    /// Check all ports that have been transfer-received in the previous task,
    /// and complete their transfer if they haven't been re-transferred.
    pub(crate) fn maybe_add_pending_ports(&self) {
        if let MessagePortState::Managed(router_id, message_ports) =
            &mut *self.message_port_state.borrow_mut()
        {
            let to_be_added: Vec<MessagePortId> = message_ports
                .iter()
                .filter_map(|(id, managed_port)| {
                    if managed_port.pending {
                        Some(*id)
                    } else {
                        None
                    }
                })
                .collect();
            for id in to_be_added.iter() {
                let managed_port = message_ports
                    .get_mut(id)
                    .expect("Collected port-id to match an entry");
                if !managed_port.pending {
                    panic!("Only pending ports should be found in to_be_added")
                }
                managed_port.pending = false;
            }
            let _ = self.script_to_constellation_chan().send(
                ScriptToConstellationMessage::CompleteMessagePortTransfer(*router_id, to_be_added),
            );
        } else {
            warn!("maybe_add_pending_ports called on a global not managing any ports.");
        }
    }

    /// <https://html.spec.whatwg.org/multipage/#ports-and-garbage-collection>
    pub(crate) fn perform_a_message_port_garbage_collection_checkpoint(&self) {
        let is_empty = if let MessagePortState::Managed(_id, message_ports) =
            &mut *self.message_port_state.borrow_mut()
        {
            let to_be_removed: Vec<MessagePortId> = message_ports
                .iter()
                .filter_map(|(id, managed_port)| {
                    if managed_port.explicitly_closed {
                        Some(*id)
                    } else {
                        None
                    }
                })
                .collect();
            for id in to_be_removed {
                message_ports.remove(&id);
            }
            // Note: ports are only removed throught explicit closure by script in this global.
            // TODO: #25772
            // TODO: remove ports when we can be sure their port message queue is empty(via the constellation).
            message_ports.is_empty()
        } else {
            false
        };
        if is_empty {
            self.remove_message_ports_router();
        }
    }

    /// Remove broadcast-channels that are closed.
    /// TODO: Also remove them if they do not have an event-listener.
    /// see <https://github.com/servo/servo/issues/25772>
    pub(crate) fn perform_a_broadcast_channel_garbage_collection_checkpoint(&self) {
        let is_empty = if let BroadcastChannelState::Managed(router_id, channels) =
            &mut *self.broadcast_channel_state.borrow_mut()
        {
            channels.retain(|name, ref mut channels| {
                channels.retain(|chan| !chan.closed());
                if channels.is_empty() {
                    let _ = self.script_to_constellation_chan().send(
                        ScriptToConstellationMessage::RemoveBroadcastChannelNameInRouter(
                            *router_id,
                            name.to_string(),
                            self.origin().immutable().clone(),
                        ),
                    );
                    false
                } else {
                    true
                }
            });
            channels.is_empty()
        } else {
            false
        };
        if is_empty {
            self.remove_broadcast_channel_router();
        }
    }

    /// Register a dependent AbortSignal that may need to be kept alive
    /// <https://dom.spec.whatwg.org/#abort-signal-garbage-collection>
    pub(crate) fn register_dependent_abort_signal(&self, signal: &AbortSignal) {
        self.abort_signal_dependents
            .borrow_mut()
            .insert(Dom::from_ref(signal));
    }

    /// Clean up dependent AbortSignals that no longer satisfy the GC predicate.
    pub(crate) fn perform_an_abort_signal_garbage_collection_checkpoint(&self) {
        let mut set = self.abort_signal_dependents.borrow_mut();

        set.retain(|dom_signal| dom_signal.must_keep_alive_for_gc());
    }

    /// Start tracking a broadcast-channel.
    pub(crate) fn track_broadcast_channel(&self, dom_channel: &BroadcastChannel) {
        let mut current_state = self.broadcast_channel_state.borrow_mut();

        if let BroadcastChannelState::UnManaged = &*current_state {
            let context = Trusted::new(self);
            let listener = BroadcastListener {
                task_source: self.task_manager().dom_manipulation_task_source().into(),
                context,
            };
            let broadcast_control_callback = GenericCallback::new(move |message| match message {
                Ok(msg) => listener.handle(msg),
                Err(err) => warn!("Error receiving a BroadcastChannelMsg: {:?}", err),
            })
            .expect("Could not generate callback");
            let router_id = BroadcastChannelRouterId::new();
            *current_state = BroadcastChannelState::Managed(router_id, HashMap::new());
            let _ = self.script_to_constellation_chan().send(
                ScriptToConstellationMessage::NewBroadcastChannelRouter(
                    router_id,
                    broadcast_control_callback,
                    self.origin().immutable().clone(),
                ),
            );
        }

        if let BroadcastChannelState::Managed(router_id, channels) = &mut *current_state {
            let entry = channels.entry(dom_channel.Name()).or_insert_with(|| {
                let _ = self.script_to_constellation_chan().send(
                    ScriptToConstellationMessage::NewBroadcastChannelNameInRouter(
                        *router_id,
                        String::from(dom_channel.Name()),
                        self.origin().immutable().clone(),
                    ),
                );
                VecDeque::new()
            });
            entry.push_back(Dom::from_ref(dom_channel));
        } else {
            panic!("track_broadcast_channel should have first switched the state to managed.");
        }
    }

    /// Start tracking a message-port
    pub(crate) fn track_message_port(
        &self,
        dom_port: &MessagePort,
        port_impl: Option<MessagePortImpl>,
    ) {
        let mut current_state = self.message_port_state.borrow_mut();

        if let MessagePortState::UnManaged = &*current_state {
            // Setup a route for IPC, for messages from the constellation to our ports.
            let context = Trusted::new(self);
            let listener = MessageListener {
                task_source: self.task_manager().port_message_queue().into(),
                context,
            };

            let port_control_callback = GenericCallback::new(move |message| match message {
                Ok(msg) => listener.notify(msg),
                Err(err) => warn!("Error receiving a MessagePortMsg: {:?}", err),
            })
            .expect("Could not create callback");
            let router_id = MessagePortRouterId::new();
            *current_state = MessagePortState::Managed(router_id, HashMapTracedValues::new_fx());
            let _ = self.script_to_constellation_chan().send(
                ScriptToConstellationMessage::NewMessagePortRouter(
                    router_id,
                    port_control_callback,
                ),
            );
        }

        if let MessagePortState::Managed(router_id, message_ports) = &mut *current_state {
            if let Some(port_impl) = port_impl {
                // We keep transfer-received ports as "pending",
                // and only ask the constellation to complete the transfer
                // if they're not re-shipped in the current task.
                message_ports.insert(
                    *dom_port.message_port_id(),
                    ManagedMessagePort {
                        port_impl: Some(port_impl),
                        dom_port: Dom::from_ref(dom_port),
                        pending: true,
                        explicitly_closed: false,
                        cross_realm_transform: None,
                    },
                );

                // Queue a task to complete the transfer,
                // unless the port is re-transferred in the current task.
                let this = Trusted::new(self);
                self.task_manager().port_message_queue().queue(
                    task!(process_pending_port_messages: move || {
                        let target_global = this.root();
                        target_global.maybe_add_pending_ports();
                    }),
                );
            } else {
                // If this is a newly-created port, let the constellation immediately know.
                let port_impl = MessagePortImpl::new(*dom_port.message_port_id());
                message_ports.insert(
                    *dom_port.message_port_id(),
                    ManagedMessagePort {
                        port_impl: Some(port_impl),
                        dom_port: Dom::from_ref(dom_port),
                        pending: false,
                        explicitly_closed: false,
                        cross_realm_transform: None,
                    },
                );
                let _ = self.script_to_constellation_chan().send(
                    ScriptToConstellationMessage::NewMessagePort(
                        *router_id,
                        *dom_port.message_port_id(),
                    ),
                );
            };
        } else {
            panic!("track_message_port should have first switched the state to managed.");
        }
    }

    /// <https://html.spec.whatwg.org/multipage/#serialization-steps>
    /// defined at <https://w3c.github.io/FileAPI/#blob-section>.
    /// Get the snapshot state and underlying bytes of the blob.
    pub(crate) fn serialize_blob(&self, blob_id: &BlobId) -> BlobImpl {
        // Note: we combine the snapshot state and underlying bytes into one call,
        // which seems spec compliant.
        // See https://w3c.github.io/FileAPI/#snapshot-state
        let bytes = self
            .get_blob_bytes(blob_id)
            .expect("Could not read bytes from blob as part of serialization steps.");
        let type_string = self.get_blob_type_string(blob_id);

        // Note: the new BlobImpl is a clone, but with it's own BlobId.
        BlobImpl::new_from_bytes(bytes, type_string)
    }

    fn track_blob_info(&self, blob_info: BlobInfo, blob_id: BlobId) {
        self.blob_state.borrow_mut().insert(blob_id, blob_info);
    }

    /// Start tracking a blob
    pub(crate) fn track_blob(&self, dom_blob: &Blob, blob_impl: BlobImpl) {
        let blob_id = blob_impl.blob_id();

        let blob_info = BlobInfo {
            blob_impl,
            tracker: BlobTracker::Blob(WeakRef::new(dom_blob)),
            has_url: false,
        };

        self.track_blob_info(blob_info, blob_id);
    }

    /// Start tracking a file
    pub(crate) fn track_file(&self, file: &File, blob_impl: BlobImpl) {
        let blob_id = blob_impl.blob_id();

        let blob_info = BlobInfo {
            blob_impl,
            tracker: BlobTracker::File(WeakRef::new(file)),
            has_url: false,
        };

        self.track_blob_info(blob_info, blob_id);
    }

    /// Clean-up any file or blob that is unreachable from script,
    /// unless it has an oustanding blob url.
    /// <https://w3c.github.io/FileAPI/#lifeTime>
    fn perform_a_blob_garbage_collection_checkpoint(&self) {
        let mut blob_state = self.blob_state.borrow_mut();
        blob_state.0.retain(|_id, blob_info| {
            let garbage_collected = match &blob_info.tracker {
                BlobTracker::File(weak) => weak.root().is_none(),
                BlobTracker::Blob(weak) => weak.root().is_none(),
            };
            if garbage_collected && !blob_info.has_url {
                if let BlobData::File(f) = blob_info.blob_impl.blob_data() {
                    self.decrement_file_ref(f.get_id());
                }
                false
            } else {
                true
            }
        });
    }

    /// Clean-up all file related resources on document unload.
    /// <https://w3c.github.io/FileAPI/#lifeTime>
    pub(crate) fn clean_up_all_file_resources(&self) {
        self.blob_state
            .borrow_mut()
            .drain()
            .for_each(|(_id, blob_info)| {
                if let BlobData::File(f) = blob_info.blob_impl.blob_data() {
                    self.decrement_file_ref(f.get_id());
                }
            });
    }

    fn decrement_file_ref(&self, id: Uuid) {
        let origin = self.origin().immutable().clone();

        let (tx, rx) = profile_generic_channel::channel(self.time_profiler_chan().clone()).unwrap();

        let msg = FileManagerThreadMsg::DecRef(id, origin, tx);
        self.send_to_file_manager(msg);
        let _ = rx.recv();
    }

    /// Get a slice to the inner data of a Blob,
    /// In the case of a File-backed blob, this might incur synchronous read and caching.
    pub(crate) fn get_blob_bytes(&self, blob_id: &BlobId) -> Result<Vec<u8>, ()> {
        let parent = {
            match *self.get_blob_data(blob_id) {
                BlobData::Sliced(parent, rel_pos) => Some((parent, rel_pos)),
                _ => None,
            }
        };

        match parent {
            Some((parent_id, rel_pos)) => self.get_blob_bytes_non_sliced(&parent_id).map(|v| {
                let range = rel_pos.to_abs_range(v.len());
                v.index(range).to_vec()
            }),
            None => self.get_blob_bytes_non_sliced(blob_id),
        }
    }

    /// Retrieve information about a specific blob from the blob store
    ///
    /// # Panics
    /// This function panics if there is no blob with the given ID.
    pub(crate) fn get_blob_data<'a>(&'a self, blob_id: &BlobId) -> Ref<'a, BlobData> {
        Ref::map(self.blob_state.borrow(), |blob_state| {
            blob_state
                .get(blob_id)
                .expect("get_blob_impl called for a unknown blob")
                .blob_impl
                .blob_data()
        })
    }

    /// Get bytes from a non-sliced blob
    fn get_blob_bytes_non_sliced(&self, blob_id: &BlobId) -> Result<Vec<u8>, ()> {
        match *self.get_blob_data(blob_id) {
            BlobData::File(ref f) => {
                let (buffer, is_new_buffer) = match f.get_cache() {
                    Some(bytes) => (bytes, false),
                    None => {
                        let bytes = self.read_file(f.get_id())?;
                        (bytes, true)
                    },
                };

                // Cache
                if is_new_buffer {
                    f.cache_bytes(buffer.clone());
                }

                Ok(buffer)
            },
            BlobData::Memory(ref s) => Ok(s.clone()),
            BlobData::Sliced(_, _) => panic!("This blob doesn't have a parent."),
        }
    }

    /// Get a slice to the inner data of a Blob,
    /// if it's a memory blob, or it's file-id and file-size otherwise.
    ///
    /// Note: this is almost a duplicate of `get_blob_bytes`,
    /// tweaked for integration with streams.
    /// TODO: merge with `get_blob_bytes` by way of broader integration with blob streams.
    fn get_blob_bytes_or_file_id(&self, blob_id: &BlobId) -> BlobResult {
        let parent = {
            match *self.get_blob_data(blob_id) {
                BlobData::Sliced(parent, rel_pos) => Some((parent, rel_pos)),
                _ => None,
            }
        };

        match parent {
            Some((parent_id, rel_pos)) => {
                match self.get_blob_bytes_non_sliced_or_file_id(&parent_id) {
                    BlobResult::Bytes(bytes) => {
                        let range = rel_pos.to_abs_range(bytes.len());
                        BlobResult::Bytes(bytes.index(range).to_vec())
                    },
                    res => res,
                }
            },
            None => self.get_blob_bytes_non_sliced_or_file_id(blob_id),
        }
    }

    /// Get bytes from a non-sliced blob if in memory, or it's file-id and file-size.
    ///
    /// Note: this is almost a duplicate of `get_blob_bytes_non_sliced`,
    /// tweaked for integration with streams.
    /// TODO: merge with `get_blob_bytes` by way of broader integration with blob streams.
    fn get_blob_bytes_non_sliced_or_file_id(&self, blob_id: &BlobId) -> BlobResult {
        match *self.get_blob_data(blob_id) {
            BlobData::File(ref f) => match f.get_cache() {
                Some(bytes) => BlobResult::Bytes(bytes),
                None => BlobResult::File(f.get_id(), f.get_size() as usize),
            },
            BlobData::Memory(ref s) => BlobResult::Bytes(s.clone()),
            BlobData::Sliced(_, _) => panic!("This blob doesn't have a parent."),
        }
    }

    /// Get a copy of the type_string of a blob.
    pub(crate) fn get_blob_type_string(&self, blob_id: &BlobId) -> String {
        let blob_state = self.blob_state.borrow();
        let blob_info = blob_state
            .get(blob_id)
            .expect("get_blob_type_string called for a unknown blob.");
        blob_info.blob_impl.type_string()
    }

    /// <https://w3c.github.io/FileAPI/#dfn-size>
    pub(crate) fn get_blob_size(&self, blob_id: &BlobId) -> u64 {
        let parent = {
            match *self.get_blob_data(blob_id) {
                BlobData::Sliced(parent, rel_pos) => Some((parent, rel_pos)),
                _ => None,
            }
        };
        match parent {
            Some((parent_id, rel_pos)) => {
                let parent_size = match *self.get_blob_data(&parent_id) {
                    BlobData::File(ref f) => f.get_size(),
                    BlobData::Memory(ref v) => v.len() as u64,
                    BlobData::Sliced(_, _) => panic!("Blob ancestry should be only one level."),
                };
                rel_pos.to_abs_range(parent_size as usize).len() as u64
            },
            None => match *self.get_blob_data(blob_id) {
                BlobData::File(ref f) => f.get_size(),
                BlobData::Memory(ref v) => v.len() as u64,
                BlobData::Sliced(_, _) => {
                    panic!("It was previously checked that this blob does not have a parent.")
                },
            },
        }
    }

    pub(crate) fn get_blob_url_id(&self, blob_id: &BlobId) -> Uuid {
        let mut blob_state = self.blob_state.borrow_mut();
        let parent = {
            let blob_info = blob_state
                .get_mut(blob_id)
                .expect("get_blob_url_id called for a unknown blob.");

            // Keep track of blobs with outstanding URLs.
            blob_info.has_url = true;

            match blob_info.blob_impl.blob_data() {
                BlobData::Sliced(parent, rel_pos) => Some((*parent, *rel_pos)),
                _ => None,
            }
        };
        match parent {
            Some((parent_id, rel_pos)) => {
                let parent_info = blob_state
                    .get_mut(&parent_id)
                    .expect("Parent of blob whose url is requested is unknown.");
                let parent_file_id = self.promote(parent_info, /* set_valid is */ false);
                let parent_size = match parent_info.blob_impl.blob_data() {
                    BlobData::File(f) => f.get_size(),
                    BlobData::Memory(v) => v.len() as u64,
                    BlobData::Sliced(_, _) => panic!("Blob ancestry should be only one level."),
                };
                let parent_size = rel_pos.to_abs_range(parent_size as usize).len() as u64;
                let blob_info = blob_state
                    .get_mut(blob_id)
                    .expect("Blob whose url is requested is unknown.");
                self.create_sliced_url_id(blob_info, &parent_file_id, &rel_pos, parent_size)
            },
            None => {
                let blob_info = blob_state
                    .get_mut(blob_id)
                    .expect("Blob whose url is requested is unknown.");
                self.promote(blob_info, /* set_valid is */ true)
            },
        }
    }

    /// Get a FileID representing sliced parent-blob content
    fn create_sliced_url_id(
        &self,
        blob_info: &mut BlobInfo,
        parent_file_id: &Uuid,
        rel_pos: &RelativePos,
        parent_len: u64,
    ) -> Uuid {
        let origin = self.origin().immutable().clone();

        let (tx, rx) = profile_generic_channel::channel(self.time_profiler_chan().clone()).unwrap();
        let msg = FileManagerThreadMsg::AddSlicedURLEntry(*parent_file_id, *rel_pos, tx, origin);
        self.send_to_file_manager(msg);
        match rx.recv().expect("File manager thread is down.") {
            Ok(new_id) => {
                *blob_info.blob_impl.blob_data_mut() = BlobData::File(FileBlob::new(
                    new_id,
                    None,
                    None,
                    rel_pos.to_abs_range(parent_len as usize).len() as u64,
                ));

                // Return the indirect id reference
                new_id
            },
            Err(_) => {
                // Return dummy id
                Uuid::new_v4()
            },
        }
    }

    /// Send a PromoteMemory message to register a new blob URL entry
    /// with the file manager for the given byte data.
    /// Return the generated UUID.
    fn promote_memory_entry(
        &self,
        blob_info: &BlobInfo,
        blob_bytes: &[u8],
        set_valid: bool,
    ) -> Uuid {
        let origin = self.origin().immutable().clone();
        let blob_buf = BlobBuf {
            filename: None,
            type_string: blob_info.blob_impl.type_string(),
            size: blob_bytes.len() as u64,
            bytes: blob_bytes.to_vec(),
        };
        let id = Uuid::new_v4();
        let msg = FileManagerThreadMsg::PromoteMemory(id, blob_buf, set_valid, origin);
        self.send_to_file_manager(msg);
        id
    }

    /// Promote non-Slice blob:
    /// 1. Memory-based: The bytes in data slice will be transferred to file manager thread.
    /// 2. File-based: If set_valid, then activate the FileID so it can serve as URL
    ///    Depending on set_valid, the returned FileID can be part of
    ///    valid or invalid Blob URL.
    pub(crate) fn promote(&self, blob_info: &mut BlobInfo, set_valid: bool) -> Uuid {
        let mut bytes = vec![];

        match blob_info.blob_impl.blob_data_mut() {
            BlobData::Sliced(_, _) => {
                panic!("Sliced blobs should use create_sliced_url_id instead of promote.");
            },
            BlobData::File(f) => {
                if set_valid {
                    // File blobs with cached byte data (converted from Memory)
                    // need a unique UUID per URL.createObjectURL call.
                    if let Some(cached_bytes) = f.get_cache() {
                        return self.promote_memory_entry(blob_info, &cached_bytes, true);
                    }

                    let origin = self.origin().immutable().clone();
                    let (tx, rx) = profile_ipc::channel(self.time_profiler_chan().clone()).unwrap();

                    let msg = FileManagerThreadMsg::ActivateBlobURL(f.get_id(), tx, origin);
                    self.send_to_file_manager(msg);

                    match rx.recv().unwrap() {
                        Ok(_) => return f.get_id(),
                        // Return a dummy id on error
                        Err(_) => return Uuid::new_v4(),
                    }
                } else {
                    // no need to activate
                    return f.get_id();
                }
            },
            BlobData::Memory(bytes_in) => mem::swap(bytes_in, &mut bytes),
        };

        let id = self.promote_memory_entry(blob_info, &bytes, set_valid);

        *blob_info.blob_impl.blob_data_mut() = BlobData::File(FileBlob::new(
            id,
            None,
            Some(bytes.to_vec()),
            bytes.len() as u64,
        ));

        id
    }

    fn send_to_file_manager(&self, msg: FileManagerThreadMsg) {
        let resource_threads = self.resource_threads();
        let _ = resource_threads.send(CoreResourceMsg::ToFileManager(msg));
    }

    fn read_file(&self, id: Uuid) -> Result<Vec<u8>, ()> {
        let recv = self.send_msg(id);
        GlobalScope::read_msg(recv)
    }

    /// <https://w3c.github.io/FileAPI/#blob-get-stream>
    pub(crate) fn get_blob_stream(
        &self,
        cx: &mut js::context::JSContext,
        blob_id: &BlobId,
    ) -> Fallible<DomRoot<ReadableStream>> {
        let (file_id, size) = match self.get_blob_bytes_or_file_id(blob_id) {
            BlobResult::Bytes(bytes) => {
                // If we have all the bytes in memory, queue them and close the stream.
                return ReadableStream::new_from_bytes_with_byte_reading_support(cx, self, bytes);
            },
            BlobResult::File(id, size) => (id, size),
        };

        let stream = ReadableStream::new_with_external_underlying_byte_source(
            cx,
            self,
            UnderlyingSourceType::Blob(size),
        )?;

        let recv = self.send_msg(file_id);

        let trusted_stream = Trusted::new(&*stream);
        let mut file_listener = FileListener {
            state: Some(FileListenerState::Empty(FileListenerTarget::Stream(
                trusted_stream,
            ))),
            task_source: self.task_manager().file_reading_task_source().into(),
        };

        ROUTER.add_typed_route(
            recv.to_ipc_receiver(),
            Box::new(move |msg| {
                file_listener.handle(msg.expect("Deserialization of file listener msg failed."));
            }),
        );

        Ok(stream)
    }

    pub(crate) fn read_file_async(
        &self,
        id: Uuid,
        promise: Rc<Promise>,
        callback: FileListenerCallback,
    ) {
        let recv = self.send_msg(id);

        let trusted_promise = TrustedPromise::new(promise);
        let mut file_listener = FileListener {
            state: Some(FileListenerState::Empty(FileListenerTarget::Promise(
                trusted_promise,
                callback,
            ))),
            task_source: self.task_manager().file_reading_task_source().into(),
        };

        ROUTER.add_typed_route(
            recv.to_ipc_receiver(),
            Box::new(move |msg| {
                file_listener.handle(msg.expect("Deserialization of file listener msg failed."));
            }),
        );
    }

    fn send_msg(&self, id: Uuid) -> profile_ipc::IpcReceiver<FileManagerResult<ReadFileProgress>> {
        let resource_threads = self.resource_threads();
        let (chan, recv) = profile_ipc::channel(self.time_profiler_chan().clone()).unwrap();
        let origin = self.origin().immutable().clone();
        let msg = FileManagerThreadMsg::ReadFile(chan, id, origin);
        let _ = resource_threads.send(CoreResourceMsg::ToFileManager(msg));
        recv
    }

    fn read_msg(
        receiver: profile_ipc::IpcReceiver<FileManagerResult<ReadFileProgress>>,
    ) -> Result<Vec<u8>, ()> {
        let mut bytes = vec![];

        loop {
            match receiver.recv().unwrap() {
                Ok(ReadFileProgress::Meta(mut blob_buf)) => {
                    bytes.append(&mut blob_buf.bytes);
                },
                Ok(ReadFileProgress::Partial(mut bytes_in)) => {
                    bytes.append(&mut bytes_in);
                },
                Ok(ReadFileProgress::EOF) => {
                    return Ok(bytes);
                },
                Err(_) => return Err(()),
            }
        }
    }

    pub(crate) fn permission_state_invocation_results(
        &self,
    ) -> &DomRefCell<HashMap<PermissionName, PermissionState>> {
        &self.permission_state_invocation_results
    }

    pub(crate) fn track_worker(
        &self,
        closing: Arc<AtomicBool>,
        join_handle: JoinHandle<()>,
        control_sender: Sender<DedicatedWorkerControlMsg>,
        context: ThreadSafeJSContext,
    ) {
        self.list_auto_close_worker
            .borrow_mut()
            .push(AutoCloseWorker {
                closing,
                join_handle: Some(join_handle),
                control_sender,
                context,
            });
    }

    pub(crate) fn track_event_source(&self, event_source: &EventSource) {
        self.event_source_tracker.track(event_source);
    }

    pub(crate) fn close_event_sources(&self) -> bool {
        let mut canceled_any_fetch = false;
        self.event_source_tracker
            .for_each(
                |event_source: DomRoot<EventSource>| match event_source.ReadyState() {
                    2 => {},
                    _ => {
                        event_source.cancel();
                        canceled_any_fetch = true;
                    },
                },
            );
        canceled_any_fetch
    }

    /// Returns the global scope of the realm that the given DOM object's reflector
    /// was created in.
    #[expect(unsafe_code)]
    pub(crate) fn from_reflector<T: DomObject>(reflector: &T) -> DomRoot<Self> {
        unsafe { GlobalScope::from_object(*reflector.reflector().get_jsobject()) }
    }

    /// Returns the global scope of the realm that the given JS object was created in.
    #[expect(unsafe_code)]
    pub(crate) unsafe fn from_object(obj: *mut JSObject) -> DomRoot<Self> {
        assert!(!obj.is_null());
        let global = unsafe { GetNonCCWObjectGlobal(obj) };
        unsafe { global_scope_from_global_static(global) }
    }

    /// Return global scope asociated with current realm
    ///
    /// Eventually we could return Handle here as global is already rooted by realm.
    #[expect(unsafe_code)]
    pub(crate) fn from_current_realm(realm: &'_ mut CurrentRealm) -> DomRoot<Self> {
        let global = realm.global().get();
        unsafe { global_scope_from_global(realm, global) }
    }

    pub(crate) fn add_uncaught_rejection(&self, rejection: HandleObject) {
        self.uncaught_rejections
            .borrow_mut()
            .push(Heap::boxed(rejection.get()));
    }

    pub(crate) fn remove_uncaught_rejection(&self, rejection: HandleObject) {
        let mut uncaught_rejections = self.uncaught_rejections.borrow_mut();

        if let Some(index) = uncaught_rejections
            .iter()
            .position(|promise| *promise == Heap::boxed(rejection.get()))
        {
            uncaught_rejections.remove(index);
        }
    }

    // `Heap` values must stay boxed, as they need semantics like `Pin`
    // (that is, they cannot be moved).
    #[allow(clippy::vec_box)]
    /// <https://html.spec.whatwg.org/multipage/#about-to-be-notified-rejected-promises-list>
    pub(crate) fn get_uncaught_rejections(&self) -> &DomRefCell<Vec<Box<Heap<*mut JSObject>>>> {
        &self.uncaught_rejections
    }

    pub(crate) fn add_consumed_rejection(&self, rejection: HandleObject) {
        self.consumed_rejections
            .borrow_mut()
            .push(Heap::boxed(rejection.get()));
    }

    pub(crate) fn remove_consumed_rejection(&self, rejection: HandleObject) {
        let mut consumed_rejections = self.consumed_rejections.borrow_mut();

        if let Some(index) = consumed_rejections
            .iter()
            .position(|promise| *promise == Heap::boxed(rejection.get()))
        {
            consumed_rejections.remove(index);
        }
    }

    // `Heap` values must stay boxed, as they need semantics like `Pin`
    // (that is, they cannot be moved).
    #[allow(clippy::vec_box)]
    pub(crate) fn get_consumed_rejections(&self) -> &DomRefCell<Vec<Box<Heap<*mut JSObject>>>> {
        &self.consumed_rejections
    }

    pub(crate) fn set_module_map(&self, request: ModuleRequest, module: ModuleStatus) {
        self.module_map.borrow_mut().insert(request, module);
    }

    pub(crate) fn get_module_map_entry(&self, request: &ModuleRequest) -> Option<ModuleStatus> {
        self.module_map.borrow().get(request).cloned()
    }

    pub(crate) fn time(&self, label: DOMString) -> Result<(), ()> {
        let mut timers = self.console_timers.borrow_mut();
        if timers.len() >= 10000 {
            return Err(());
        }
        match timers.entry(label) {
            Entry::Vacant(entry) => {
                entry.insert(Instant::now());
                Ok(())
            },
            Entry::Occupied(_) => Err(()),
        }
    }

    /// Computes the delta time since a label has been created
    ///
    /// Returns an error if the label does not exist.
    pub(crate) fn time_log(&self, label: &DOMString) -> Result<u64, ()> {
        self.console_timers
            .borrow()
            .get(label)
            .ok_or(())
            .map(|&start| (Instant::now() - start).as_millis() as u64)
    }

    /// Computes the delta time since a label has been created and stops
    /// tracking the label.
    ///
    /// Returns an error if the label does not exist.
    pub(crate) fn time_end(&self, label: &DOMString) -> Result<u64, ()> {
        self.console_timers
            .borrow_mut()
            .remove(label)
            .ok_or(())
            .map(|start| (Instant::now() - start).as_millis() as u64)
    }

    /// Get an `&IpcSender<ScriptToDevtoolsControlMsg>` to send messages
    /// to the devtools thread when available.
    pub(crate) fn devtools_chan(&self) -> Option<&GenericCallback<ScriptToDevtoolsControlMsg>> {
        self.devtools_chan.as_ref()
    }

    /// Get a sender to the memory profiler thread.
    pub(crate) fn mem_profiler_chan(&self) -> &profile_mem::ProfilerChan {
        &self.mem_profiler_chan
    }

    /// Get a sender to the time profiler thread.
    pub(crate) fn time_profiler_chan(&self) -> &profile_time::ProfilerChan {
        &self.time_profiler_chan
    }

    /// Get a sender to the constellation thread.
    pub(crate) fn script_to_constellation_chan(&self) -> ScriptToConstellationChan {
        ScriptToConstellationChan {
            sender: self.script_to_constellation_sender.clone(),
            webview_id: self.webview_id().unwrap_or(TEST_WEBVIEW_ID),
            pipeline_id: self.pipeline_id(),
        }
    }

    pub(crate) fn script_to_embedder_chan(&self) -> &ScriptToEmbedderChan {
        &self.script_to_embedder_chan
    }

    pub(crate) fn send_to_embedder(&self, msg: EmbedderMsg) {
        self.script_to_embedder_chan().send(msg).unwrap();
    }

    /// Get the `PipelineId` for this global scope.
    pub(crate) fn pipeline_id(&self) -> PipelineId {
        if let Some(worker) = self.downcast::<WorkerGlobalScope>() {
            worker.pipeline_id()
        } else if let Some(window) = self.downcast::<Window>() {
            window.pipeline_id()
        } else if let Some(debugger) = self.downcast::<DebuggerGlobalScope>() {
            debugger.pipeline_id()
        } else if let Some(worklet) = self.downcast::<WorkletGlobalScope>() {
            worklet.pipeline_id()
        } else if let Some(dissimilar) = self.downcast::<DissimilarOriginWindow>() {
            dissimilar.pipeline_id()
        } else {
            unreachable!("Unsupported global type for pipeline id")
        }
    }

    /// Register interest in a notification category. Sends a `RegisterInterest`
    /// message to the constellation when the first listener is registered.
    pub(crate) fn register_interest(&self, interest: ConstellationInterest) {
        let mut counts = self.constellation_interest_counts.borrow_mut();
        let count = counts.entry(interest).or_insert(0);
        *count += 1;
        if *count == 1 {
            let _ = self
                .script_to_constellation_chan()
                .send(ScriptToConstellationMessage::RegisterInterest(interest));
        }
    }

    /// Unregister interest in a notification category. Sends an `UnregisterInterest`
    /// message to the constellation when the last listener is removed.
    pub(crate) fn unregister_interest(&self, interest: ConstellationInterest) {
        let mut counts = self.constellation_interest_counts.borrow_mut();
        if let Some(count) = counts.get_mut(&interest) {
            *count = count.saturating_sub(1);
            if *count == 0 {
                counts.remove(&interest);
                let _ = self
                    .script_to_constellation_chan()
                    .send(ScriptToConstellationMessage::UnregisterInterest(interest));
            }
        }
    }

    /// Get the origin for this global scope
    pub(crate) fn origin(&self) -> MutableOrigin {
        if let Some(window) = self.downcast::<Window>() {
            window.origin()
        } else if let Some(worker) = self.downcast::<WorkerGlobalScope>() {
            worker.origin()
        } else if let Some(worklet) = self.downcast::<WorkletGlobalScope>() {
            worklet.origin()
        } else if let Some(dissimilar_window) = self.downcast::<DissimilarOriginWindow>() {
            dissimilar_window.origin()
        } else if let Some(debugger) = self.downcast::<DebuggerGlobalScope>() {
            debugger.origin()
        } else {
            unreachable!("Unexpected origin check against global")
        }
    }

    /// Get the creation_url for this global scope
    pub(crate) fn creation_url(&self) -> ServoUrl {
        self.creation_url.borrow().clone()
    }

    pub(crate) fn set_creation_url(&self, creation_url: ServoUrl) {
        *self.creation_url.borrow_mut() = creation_url;
    }

    /// Get the top_level_creation_url for this global scope
    pub(crate) fn top_level_creation_url(&self) -> &Option<ServoUrl> {
        &self.top_level_creation_url
    }

    pub(crate) fn image_cache(&self) -> Arc<dyn ImageCache> {
        if let Some(window) = self.downcast::<Window>() {
            return window.image_cache();
        }
        if let Some(worker) = self.downcast::<DedicatedWorkerGlobalScope>() {
            return worker.image_cache();
        }
        if let Some(worker) = self.downcast::<SharedWorkerGlobalScope>() {
            return worker.image_cache();
        }
        if let Some(worker) = self.downcast::<PaintWorkletGlobalScope>() {
            return worker.image_cache();
        }
        unreachable!();
    }

    /// Schedule a [`TimerEventRequest`] on this [`GlobalScope`]'s [`timers::TimerScheduler`].
    /// Every Worker has its own scheduler, which handles events in the Worker event loop,
    /// but `Window`s use a shared scheduler associated with their [`ScriptThread`].
    pub(crate) fn schedule_timer(&self, request: TimerEventRequest) -> Option<TimerId> {
        match self.downcast::<WorkerGlobalScope>() {
            Some(worker_global) => Some(worker_global.timer_scheduler().schedule_timer(request)),
            _ => with_script_thread(|script_thread| Some(script_thread.schedule_timer(request))),
        }
    }

    /// <https://html.spec.whatwg.org/multipage/#nested-browsing-context>
    pub(crate) fn is_nested_browsing_context(&self) -> bool {
        self.downcast::<Window>()
            .is_some_and(|window| !window.is_top_level())
    }

    /// Obtain the size of in flight keep alive records from the resource thread.
    /// If we can't communicate with the thread, we return u64::MAX to ensure
    /// the limit is higher than what is allowed. This ensures that whenever
    /// we want to initiate a keep alive request and the thread doesn't communicate,
    /// we block additional keep alive requests.
    pub(crate) fn total_size_of_in_flight_keep_alive_records(&self) -> u64 {
        let (sender, receiver) = generic_channel::channel().unwrap();
        if self
            .core_resource_thread()
            .send(CoreResourceMsg::TotalSizeOfInFlightKeepAliveRecords(
                self.pipeline_id(),
                sender,
            ))
            .is_err()
        {
            return u64::MAX;
        }
        receiver.recv().unwrap_or(u64::MAX)
    }

    /// Part of <https://fetch.spec.whatwg.org/#populate-request-from-client>
    pub(crate) fn request_client(&self, no_gc: Option<&NoGC>) -> RequestClient {
        if let Some(window) = self.downcast::<Window>() {
            return window.request_client(no_gc);
        }
        RequestClient {
            preloaded_resources: Default::default(),
            policy_container: self.policy_container(),
            origin: RequestOrigin::Origin(self.origin().immutable().clone()),
            is_nested_browsing_context: false,
            insecure_requests_policy: self.insecure_requests_policy(),
            has_trustworthy_ancestor_origin: false,
        }
    }

    /// <https://html.spec.whatwg.org/multipage/#concept-settings-object-policy-container>
    pub(crate) fn policy_container(&self) -> PolicyContainer {
        if let Some(window) = self.downcast::<Window>() {
            return window.Document().policy_container().to_owned();
        }
        if let Some(worker) = self.downcast::<WorkerGlobalScope>() {
            return worker.policy_container().to_owned();
        }
        unreachable!();
    }

    /// Get the [base url](https://html.spec.whatwg.org/multipage/#api-base-url)
    /// for this global scope.
    pub(crate) fn api_base_url(&self) -> ServoUrl {
        if let Some(window) = self.downcast::<Window>() {
            // https://html.spec.whatwg.org/multipage/#script-settings-for-browsing-contexts:api-base-url
            return window.Document().base_url();
        }
        if let Some(worker) = self.downcast::<WorkerGlobalScope>() {
            // https://html.spec.whatwg.org/multipage/#script-settings-for-workers:api-base-url
            return worker.get_url().clone();
        }
        if let Some(worklet) = self.downcast::<WorkletGlobalScope>() {
            // https://drafts.css-houdini.org/worklets/#script-settings-for-worklets
            return worklet.base_url();
        }
        if let Some(_debugger_global) = self.downcast::<DebuggerGlobalScope>() {
            return self.creation_url();
        }
        unreachable!();
    }

    /// Get the URL for this global scope.
    pub(crate) fn get_url(&self) -> ServoUrl {
        if let Some(window) = self.downcast::<Window>() {
            return window.get_url();
        }
        if let Some(worker) = self.downcast::<WorkerGlobalScope>() {
            return worker.get_url().clone();
        }
        if let Some(worklet) = self.downcast::<WorkletGlobalScope>() {
            // TODO: is this the right URL to return?
            return worklet.base_url();
        }
        if let Some(_debugger_global) = self.downcast::<DebuggerGlobalScope>() {
            return self.creation_url();
        }
        unreachable!();
    }

    /// Get the Referrer Policy for this global scope.
    pub(crate) fn get_referrer_policy(&self) -> ReferrerPolicy {
        if let Some(window) = self.downcast::<Window>() {
            let document = window.Document();

            return document.get_referrer_policy();
        }
        if let Some(worker) = self.downcast::<WorkerGlobalScope>() {
            return worker.policy_container().get_referrer_policy();
        }
        unreachable!();
    }

    /// Step 3."client" of <https://w3c.github.io/webappsec-referrer-policy/#determine-requests-referrer>
    /// Determine the Referrer for a request whose Referrer is "client"
    pub(crate) fn get_referrer(&self) -> Referrer {
        // Substep 3."client".2. If environment’s global object is a Window object, then
        if let Some(window) = self.downcast::<Window>() {
            // Substep 3."client".2.1. Let document be the associated Document of environment’s global object.
            let mut document = window.Document();

            // Substep 3."client".2.2. If document’s origin is an opaque origin, return no referrer.
            if let ImmutableOrigin::Opaque(_) = document.origin().immutable() {
                return Referrer::NoReferrer;
            }

            let mut url = document.url();

            // Substep 3."client".2.3. While document is an iframe srcdoc document,
            // let document be document’s browsing context’s browsing context container’s node document.
            while url.as_str() == "about:srcdoc" {
                // Return early if we cannot get a parent document. This might happen if
                // this iframe was already removed from the parent page.
                let Some(parent_document) =
                    document.browsing_context().and_then(|browsing_context| {
                        browsing_context
                            .parent()
                            .and_then(|parent| parent.document())
                    })
                else {
                    return Referrer::NoReferrer;
                };
                document = parent_document;
                url = document.url();
            }

            // Substep 3."client".2.4. Let referrerSource be document’s URL.
            Referrer::Client(url)
        } else {
            // Substep 3."client".3. Otherwise, let referrerSource be environment’s creation URL.
            Referrer::Client(self.creation_url())
        }
    }

    /// Extract a `Window`, panic if the global object is not a `Window`.
    pub(crate) fn as_window(&self) -> &Window {
        self.downcast::<Window>().expect("expected a Window scope")
    }

    /// Returns a policy that should be used for fetches initiated from this global.
    pub(crate) fn insecure_requests_policy(&self) -> InsecureRequestsPolicy {
        if let Some(window) = self.downcast::<Window>() {
            return window.Document().insecure_requests_policy();
        }
        if let Some(worker) = self.downcast::<WorkerGlobalScope>() {
            return worker.insecure_requests_policy();
        }
        debug!("unsupported global, defaulting insecure requests policy to DoNotUpgrade");
        InsecureRequestsPolicy::DoNotUpgrade
    }

    /// Whether this document has ancestor navigables that are trustworthy
    pub(crate) fn has_trustworthy_ancestor_origin(&self) -> bool {
        self.downcast::<Window>()
            .is_some_and(|window| window.Document().has_trustworthy_ancestor_origin())
    }

    /// <https://html.spec.whatwg.org/multipage/#report-an-exception>
    pub(crate) fn report_an_exception(&self, cx: &mut js::context::JSContext, error: HandleValue) {
        // Step 2. Let errorInfo be the result of extracting error information from exception.
        let error_info = ErrorInfo::from_value(cx, error);

        // Step 3. Let script be a script found in an implementation-defined way, or null.
        // This should usually be the running script (most notably during run a classic script).
        // Step 4. If script is a classic script and script's muted errors is true, then set
        // errorInfo[error] to null, errorInfo[message] to "Script error.", errorInfo[filename]
        // to the empty string, errorInfo[lineno] to 0, and errorInfo[colno] to 0.
        // Note: This is handled in 'run_a_classic_script'.

        // Step 5. If omitError is true, then set errorInfo[error] to null.
        //
        // `omitError` defaults to `false`

        // Steps 6-7
        self.report_an_error(cx, error_info, error);
    }

    /// Steps 6-7 of <https://html.spec.whatwg.org/multipage/#report-an-exception>
    pub(crate) fn report_an_error(
        &self,
        cx: &mut js::context::JSContext,
        error_info: ErrorInfo,
        value: HandleValue,
    ) {
        self.send_to_embedder(EmbedderMsg::ShowConsoleApiMessage(
            self.webview_id(),
            ConsoleLogLevel::Error,
            format!(
                "Error at {}:{}:{} {}",
                error_info.filename, error_info.lineno, error_info.column, error_info.message
            ),
        ));

        #[cfg(feature = "js_backtrace")]
        LAST_EXCEPTION_BACKTRACE.with(|backtrace| {
            if let Some((js_backtrace, rust_backtrace)) = backtrace.borrow_mut().take() {
                if let Some(stack) = js_backtrace {
                    error!("JS backtrace:\n{}", stack);
                }
                error!("Rust backtrace:\n{}", rust_backtrace);
            }
        });

        // Step 1. Let notHandled be true.
        let mut not_handled = true;

        // Step 6. If global is not in error reporting mode:
        if !self.in_error_reporting_mode.get() {
            // Step 6.1. Set global's in error reporting mode to true.
            self.in_error_reporting_mode.set(true);

            // Step 6.2 If global implements EventTarget, then set notHandled to the result of
            // firing an event named error at global, using ErrorEvent, with the cancelable
            // attribute initialized to true, and additional attributes initialized according to
            // errorInfo.
            let event = ErrorEvent::new(
                cx,
                self,
                atom!("error"),
                EventBubbles::DoesNotBubble,
                EventCancelable::Cancelable,
                error_info.message.as_str().into(),
                error_info.filename.as_str().into(),
                error_info.lineno,
                error_info.column,
                value,
            );
            not_handled = event
                .upcast::<Event>()
                .fire(cx, self.upcast::<EventTarget>());

            // Step 6.3. Set global's in error reporting mode to false.
            self.in_error_reporting_mode.set(false);
        }

        // Step 7. If notHandled is true, then:
        if not_handled {
            // Step 7.2. If global implements DedicatedWorkerGlobalScope,
            // queue a global task on the DOM manipulation task source with the
            // global's associated Worker's relevant global object to run these steps:
            //
            // https://html.spec.whatwg.org/multipage/#runtime-script-errors-2
            if let Some(dedicated) = self.downcast::<DedicatedWorkerGlobalScope>() {
                dedicated.forward_error_to_worker_object(error_info);
            } else if self.is::<Window>() {
                // Step 7.3. Otherwise, the user agent may report exception to a developer console.
                if let Some(ref chan) = self.devtools_chan {
                    let _ = chan.send(ScriptToDevtoolsControlMsg::ReportPageError(
                        self.pipeline_id(),
                        PageError {
                            error_message: error_info.message.clone(),
                            source_name: error_info.filename.clone(),
                            line_number: error_info.lineno,
                            column_number: error_info.column,
                            time_stamp: get_time_stamp(),
                        },
                    ));
                }
            }
        }
    }

    /// Get the `&ResourceThreads` for this global scope.
    pub(crate) fn resource_threads(&self) -> &ResourceThreads {
        &self.resource_threads
    }

    /// Get the `CoreResourceThread` for this global scope.
    pub(crate) fn core_resource_thread(&self) -> CoreResourceThread {
        self.resource_threads().sender()
    }

    /// Get a reference to the [`StorageThreads`] for this [`GlobalScope`].
    pub(crate) fn storage_threads(&self) -> &StorageThreads {
        &self.storage_threads
    }

    /// A sender to the event loop of this global scope. This either sends to the Worker event loop
    /// or the ScriptThread event loop in the case of a `Window`. This can be `None` for dedicated
    /// workers that are not currently handling a message.
    pub(crate) fn event_loop_sender(&self) -> Option<ScriptEventLoopSender> {
        if let Some(window) = self.downcast::<Window>() {
            Some(window.event_loop_sender())
        } else if let Some(dedicated) = self.downcast::<DedicatedWorkerGlobalScope>() {
            dedicated.event_loop_sender()
        } else if let Some(shared_worker) = self.downcast::<SharedWorkerGlobalScope>() {
            Some(shared_worker.event_loop_sender())
        } else if let Some(service_worker) = self.downcast::<ServiceWorkerGlobalScope>() {
            Some(service_worker.event_loop_sender())
        } else {
            unreachable!(
                "Tried to access event loop sender for incompatible \
                 GlobalScope (PaintWorklet or DissimilarOriginWindow)"
            );
        }
    }

    /// A reference to the [`TaskManager`] used to schedule tasks for this [`GlobalScope`].
    pub(crate) fn task_manager(&self) -> Rc<TaskManager> {
        if let Some(worker) = self.downcast::<WorkerGlobalScope>() {
            worker.task_manager()
        } else if let Some(window) = self.downcast::<Window>() {
            window.task_manager()
        } else {
            unreachable!("Attempted to use task manager with unsupported global");
        }
    }

    /// Evaluate JS code on this global scope.
    #[expect(unsafe_code)]
    pub(crate) fn evaluate_js_on_global(
        &self,
        cx: &mut CurrentRealm,
        code: Cow<'_, str>,
        filename: &str,
        introduction_type: Option<&'static CStr>,
        rval: Option<MutableHandleValue>,
    ) -> Result<(), JavaScriptEvaluationError> {
        assert!(self.can_run_script());

        run_a_script::<DomTypeHolder, _, _>(cx, self, |cx| {
            let url = self.api_base_url();
            let fetch_options = ScriptFetchOptions::default_classic_script();

            let options = fill_compile_options(
                cx,
                filename,
                introduction_type,
                ErrorReporting::Unmuted,
                rval.is_none(), // noScriptRval
                1,              // lineno
            );

            let mut source = transform_str_to_source_text(&code);
            rooted!(&in(cx) let compiled_script = unsafe { Compile1(cx, options.ptr, &mut source) });

            let Some(script) = NonNull::new(*compiled_script) else {
                debug!("error compiling Dom string");
                report_pending_exception(cx);
                return Err(JavaScriptEvaluationError::CompilationFailure);
            };

            rooted!(&in(cx) let mut value = UndefinedValue());
            let rval = rval.unwrap_or_else(|| value.handle_mut());

            if !evaluate_script(cx, script, url, fetch_options, rval) {
                let error_info = take_and_report_pending_exception_for_api(cx);
                return Err(JavaScriptEvaluationError::EvaluationFailure(error_info));
            }

            maybe_resume_unwind();
            Ok(())
        })
    }

    /// <https://html.spec.whatwg.org/multipage/#timer-initialisation-steps>
    pub(crate) fn schedule_callback(
        &self,
        callback: OneshotTimerCallback,
        duration: Duration,
    ) -> OneshotTimerHandle {
        self.with_timers(|timers| timers.schedule_callback(callback, duration, self.timer_source()))
    }

    pub(crate) fn unschedule_callback(&self, handle: OneshotTimerHandle) {
        self.with_timers(|timers| timers.unschedule_callback(handle));
    }

    /// <https://html.spec.whatwg.org/multipage/#timer-initialisation-steps>
    pub(crate) fn set_timeout_or_interval(
        &self,
        cx: &mut js::context::JSContext,
        callback: TimerCallback,
        arguments: Vec<HandleValue>,
        timeout: Duration,
        is_interval: IsInterval,
    ) -> Fallible<i32> {
        self.with_timers(|timers| {
            timers.set_timeout_or_interval(
                cx,
                self,
                callback,
                arguments,
                timeout,
                is_interval,
                self.timer_source(),
            )
        })
    }

    pub(crate) fn clear_timeout_or_interval(&self, handle: i32) {
        self.with_timers(|timers| timers.clear_timeout_or_interval(self, handle));
    }

    pub(crate) fn fire_timer(&self, handle: TimerEventId, cx: &mut js::context::JSContext) {
        self.with_timers(|timers| timers.fire_timer(handle, cx));
    }

    pub(crate) fn resume(&self) {
        self.with_timers(|timers| timers.resume());
    }

    pub(crate) fn suspend(&self) {
        self.with_timers(|timers| timers.suspend());
    }

    pub(crate) fn slow_down_timers(&self) {
        self.with_timers(|timers| timers.slow_down());
    }

    pub(crate) fn speed_up_timers(&self) {
        self.with_timers(|timers| timers.speed_up());
    }

    fn timer_source(&self) -> TimerSource {
        if self.is::<Window>() {
            return TimerSource::FromWindow(self.pipeline_id());
        }
        if self.is::<WorkerGlobalScope>() {
            return TimerSource::FromWorker;
        }
        unreachable!();
    }

    /// Returns a boolean indicating whether the event-loop
    /// where this global is running on can continue running JS.
    pub(crate) fn can_continue_running(&self) -> bool {
        if self.is::<Window>() {
            return ScriptThread::can_continue_running();
        }
        if let Some(worker) = self.downcast::<WorkerGlobalScope>() {
            return !worker.is_closing();
        }

        // TODO: plug worklets into this.
        true
    }

    /// Potentially instantiate and return this [`GlobalScope`]'s [`IDBFactory`].
    pub(crate) fn ensure_indexeddb_factory(
        &self,
        cx: &mut js::context::JSContext,
    ) -> DomRoot<IDBFactory> {
        self.indexeddb.or_init(|| IDBFactory::new(cx, self))
    }

    /// Return this [`GlobalScope`]'s [`IDBFactory`] if it has previously been instantiated.
    pub(crate) fn indexeddb_factory(&self) -> Option<DomRoot<IDBFactory>> {
        self.indexeddb.get()
    }

    /// Perform a microtask checkpoint.
    pub(crate) fn perform_a_microtask_checkpoint(&self, cx: &mut js::context::JSContext) {
        if let Some(window) = self.downcast::<Window>() {
            window.perform_a_microtask_checkpoint(cx);
        } else if let Some(worker) = self.downcast::<WorkerGlobalScope>() {
            worker.perform_a_microtask_checkpoint(cx);
        }
    }

    /// Enqueue a microtask for subsequent execution.
    pub(crate) fn enqueue_microtask(
        &self,
        cx: &js::context::JSContext,
        job: Box<dyn MicrotaskRunnable>,
    ) {
        if self.is::<Window>() {
            ScriptThread::enqueue_microtask(cx, job);
        } else if let Some(worker) = self.downcast::<WorkerGlobalScope>() {
            worker.enqueue_microtask(cx, job);
        }
    }

    /// Create a new sender/receiver pair that can be used to implement an on-demand
    /// event loop. Used for implementing web APIs that require blocking semantics
    /// without resorting to nested event loops.
    pub(crate) fn new_script_pair(&self) -> (ScriptEventLoopSender, ScriptEventLoopReceiver) {
        if let Some(window) = self.downcast::<Window>() {
            return window.new_script_pair();
        }
        if let Some(worker) = self.downcast::<WorkerGlobalScope>() {
            return worker.new_script_pair();
        }
        unreachable!();
    }

    /// Process a single event as if it were the next event
    /// in the queue for the event-loop where this global scope is running on.
    /// Returns a boolean indicating whether further events should be processed.
    pub(crate) fn process_event(
        &self,
        msg: CommonScriptMsg,
        cx: &mut js::context::JSContext,
    ) -> bool {
        if self.is::<Window>() {
            return ScriptThread::process_event(msg, cx);
        }
        if let Some(worker) = self.downcast::<WorkerGlobalScope>() {
            return worker.process_event(msg, cx);
        }
        unreachable!();
    }

    pub(crate) fn runtime_handle(&self) -> ParentRuntime {
        if self.is::<Window>() {
            ScriptThread::runtime_handle()
        } else if let Some(worker) = self.downcast::<WorkerGlobalScope>() {
            worker.runtime_handle()
        } else {
            unreachable!()
        }
    }

    /// Returns the ["current"] global object.
    ///
    /// ["current"]: https://html.spec.whatwg.org/multipage/#current
    #[expect(unsafe_code)]
    pub(crate) fn current() -> Option<DomRoot<Self>> {
        let mut cx = unsafe { JSContext::get_from_thread()? };
        unsafe {
            let global = CurrentGlobalOrNull(&cx);
            if global.is_null() {
                None
            } else {
                Some(global_scope_from_global(&mut cx, global))
            }
        }
    }

    /// Returns the ["entry"] global object.
    ///
    /// ["entry"]: https://html.spec.whatwg.org/multipage/#entry
    pub(crate) fn entry() -> DomRoot<Self> {
        entry_global()
    }

    /// Returns the ["incumbent"] global object.
    ///
    /// ["incumbent"]: https://html.spec.whatwg.org/multipage/#incumbent
    pub(crate) fn incumbent() -> Option<DomRoot<Self>> {
        incumbent_global()
    }

    pub(crate) fn performance(&self, cx: &mut JSContext) -> DomRoot<Performance> {
        if let Some(window) = self.downcast::<Window>() {
            return window.Performance(cx);
        }
        if let Some(worker) = self.downcast::<WorkerGlobalScope>() {
            return worker.Performance(cx);
        }
        unreachable!();
    }

    /// <https://w3c.github.io/performance-timeline/#supportedentrytypes-attribute>
    pub(crate) fn supported_performance_entry_types(
        &self,
        cx: &mut js::context::JSContext,
        retval: MutableHandleValue,
    ) {
        self.frozen_supported_performance_entry_types.get_or_init(
            cx,
            || {
                EntryType::VARIANTS
                    .iter()
                    .map(|t| DOMString::from(t.as_str()))
                    .collect()
            },
            retval,
        );
    }

    pub(crate) fn inherited_secure_context(&self) -> Option<bool> {
        self.inherited_secure_context
    }

    /// <https://html.spec.whatwg.org/multipage/#secure-context>
    pub(crate) fn is_secure_context(&self) -> bool {
        // This differs from the specification, but it seems that
        // `inherited_secure_context` implements more-or-less the exact same logic, in a
        // different manner. Workers inherit whether or not their in a secure context and
        // worklets do as well (they can only be created in secure contexts).
        if Some(false) == self.inherited_secure_context {
            return false;
        }
        // Step 1. If environment is an environment settings object, then:
        // Step 1.1. Let global be environment's global object.
        match self.top_level_creation_url() {
            None => {
                // Workers and worklets don't have a top-level creation URL
                assert!(self.is::<WorkerGlobalScope>() || self.is::<WorkletGlobalScope>());
                true
            },
            Some(top_level_creation_url) => {
                assert!(self.is::<Window>());
                // Step 2. If the result of Is url potentially trustworthy?
                // given environment's top-level creation URL is "Potentially Trustworthy", then return true.
                // Step 3. Return false.
                if top_level_creation_url.scheme() == "blob" &&
                    Some(true) == self.inherited_secure_context
                {
                    return true;
                }
                top_level_creation_url.is_potentially_trustworthy()
            },
        }
    }

    /// <https://www.w3.org/TR/CSP/#get-csp-of-object>
    pub(crate) fn get_csp_list(&self) -> Option<CspList> {
        if self.is::<Window>() || self.is::<WorkerGlobalScope>() {
            return self.policy_container().csp_list;
        }
        // TODO: Worklet global scopes.
        None
    }

    pub(crate) fn status_code(&self) -> Option<u16> {
        if let Some(window) = self.downcast::<Window>() {
            return window.Document().status_code();
        }
        None
    }

    #[cfg(feature = "webgpu")]
    pub(crate) fn wgpu_id_hub(&self) -> Arc<IdentityHub> {
        self.gpu_id_hub.clone()
    }

    #[cfg(feature = "webgpu")]
    pub(crate) fn add_gpu_device(&self, device: &GPUDevice) {
        self.gpu_devices
            .borrow_mut()
            .insert(device.id(), WeakRef::new(device));
    }

    #[cfg(feature = "webgpu")]
    pub(crate) fn remove_gpu_device(&self, device: WebGPUDevice) {
        let device = self
            .gpu_devices
            .borrow_mut()
            .remove(&device)
            .expect("GPUDevice should still be in devices hashmap");
        assert!(device.root().is_none())
    }

    #[cfg(feature = "webgpu")]
    pub(crate) fn gpu_device_lost(
        &self,
        device: WebGPUDevice,
        reason: DeviceLostReason,
        msg: String,
    ) {
        let reason = match reason {
            DeviceLostReason::Unknown => GPUDeviceLostReason::Unknown,
            DeviceLostReason::Destroyed => GPUDeviceLostReason::Destroyed,
        };
        if let Some(device) = self
            .gpu_devices
            .borrow_mut()
            .get_mut(&device)
            .expect("GPUDevice should still be in devices hashmap")
            .root()
        {
            device.lose(reason, msg);
        }
    }

    #[cfg(feature = "webgpu")]
    pub(crate) fn handle_uncaptured_gpu_error(
        &self,
        device: WebGPUDevice,
        error: webgpu_traits::Error,
    ) {
        if let Some(gpu_device) = self
            .gpu_devices
            .borrow()
            .get(&device)
            .and_then(|device| device.root())
        {
            gpu_device.fire_uncaptured_error(error);
        } else {
            warn!("Recived error for lost GPUDevice!")
        }
    }

    pub(crate) fn current_group_label(&self) -> Option<DOMString> {
        self.console_group_stack
            .borrow()
            .last()
            .map(|label| DOMString::from(format!("[{}]", label)))
    }

    pub(crate) fn push_console_group(&self, group: DOMString) {
        self.console_group_stack.borrow_mut().push(group);
    }

    pub(crate) fn pop_console_group(&self) {
        let _ = self.console_group_stack.borrow_mut().pop();
    }

    pub(crate) fn increment_console_count(&self, label: &DOMString) -> usize {
        *self
            .console_count_map
            .borrow_mut()
            .entry(label.clone())
            .and_modify(|e| *e += 1)
            .or_insert(1)
    }

    pub(crate) fn reset_console_count(&self, label: &DOMString) -> Result<(), ()> {
        match self.console_count_map.borrow_mut().get_mut(label) {
            Some(value) => {
                *value = 0;
                Ok(())
            },
            None => Err(()),
        }
    }

    pub(crate) fn structured_clone(
        &self,
        cx: &mut js::context::JSContext,
        value: HandleValue,
        options: RootedTraceableBox<StructuredSerializeOptions>,
        retval: MutableHandleValue,
    ) -> Fallible<()> {
        let mut rooted = CustomAutoRooter::new(
            options
                .transfer
                .iter()
                .map(|js: &RootedTraceableBox<Heap<*mut JSObject>>| js.get())
                .collect(),
        );

        #[expect(unsafe_code)]
        let guard = unsafe { CustomAutoRooterGuard::new(cx.raw_cx(), &mut rooted) };

        let data = structuredclone::write(cx, value, Some(guard))?;

        structuredclone::read(cx, self, data, retval)?;

        Ok(())
    }

    pub(crate) fn fetch<Listener: FetchResponseListener>(
        &self,
        request_builder: RequestBuilder,
        context: Listener,
        task_source: SendableTaskSource,
    ) {
        let network_listener = NetworkListener::new(context, task_source);
        self.fetch_with_network_listener(request_builder, network_listener);
    }

    pub(crate) fn fetch_with_network_listener<Listener: FetchResponseListener>(
        &self,
        request_builder: RequestBuilder,
        network_listener: NetworkListener<Listener>,
    ) {
        fetch_async(
            &self.core_resource_thread(),
            request_builder,
            None,
            network_listener.into_callback(),
        );
    }

    pub(crate) fn unminify_js(&self) -> bool {
        self.unminified_js_dir.is_some()
    }

    pub(crate) fn unminified_js_dir(&self) -> Option<String> {
        self.unminified_js_dir.clone()
    }

    pub(crate) fn set_byte_length_queuing_strategy_size(&self, function: Rc<Function>) {
        if self
            .byte_length_queuing_strategy_size_function
            .set(function)
            .is_err()
        {
            warn!("byte length queuing strategy size function is set twice.");
        };
    }

    pub(crate) fn get_byte_length_queuing_strategy_size(&self) -> Option<Rc<Function>> {
        self.byte_length_queuing_strategy_size_function
            .get()
            .cloned()
    }

    pub(crate) fn set_count_queuing_strategy_size(&self, function: Rc<Function>) {
        if self
            .count_queuing_strategy_size_function
            .set(function)
            .is_err()
        {
            warn!("count queuing strategy size function is set twice.");
        };
    }

    pub(crate) fn get_count_queuing_strategy_size(&self) -> Option<Rc<Function>> {
        self.count_queuing_strategy_size_function.get().cloned()
    }

    pub(crate) fn add_notification_permission_request_callback(
        &self,
        callback_id: String,
        callback: Rc<NotificationPermissionCallback>,
    ) {
        self.notification_permission_request_callback_map
            .borrow_mut()
            .insert(callback_id, callback);
    }

    pub(crate) fn remove_notification_permission_request_callback(
        &self,
        callback_id: String,
    ) -> Option<Rc<NotificationPermissionCallback>> {
        self.notification_permission_request_callback_map
            .borrow_mut()
            .remove(&callback_id)
    }

    pub(crate) fn append_deferred_fetch(
        &self,
        deferred_fetch: QueuedDeferredFetchRecord,
    ) -> DeferredFetchRecordId {
        let deferred_record_id = DeferredFetchRecordId::default();
        self.fetch_group
            .borrow_mut()
            .deferred_fetch_records
            .insert(deferred_record_id, deferred_fetch);
        deferred_record_id
    }

    pub(crate) fn deferred_fetches(&self) -> Vec<QueuedDeferredFetchRecord> {
        self.fetch_group
            .borrow()
            .deferred_fetch_records
            .values()
            .cloned()
            .collect()
    }

    pub(crate) fn deferred_fetch_record_for_id(
        &self,
        deferred_fetch_record_id: &DeferredFetchRecordId,
    ) -> QueuedDeferredFetchRecord {
        self.fetch_group
            .borrow()
            .deferred_fetch_records
            .get(deferred_fetch_record_id)
            .expect("Should always use a generated fetch_record_id instead of passing your own")
            .clone()
    }

    /// <https://fetch.spec.whatwg.org/#process-deferred-fetches>
    pub(crate) fn process_deferred_fetches(&self) {
        // Step 1. For each deferred fetch record deferredRecord of fetchGroup’s
        // deferred fetch records, process a deferred fetch deferredRecord.
        for deferred_fetch in self.deferred_fetches() {
            deferred_fetch.process(self);
        }
    }

    pub(crate) fn import_map(&self) -> Ref<'_, ImportMap> {
        self.import_map.borrow()
    }

    pub(crate) fn import_map_mut(&self) -> RefMut<'_, ImportMap> {
        self.import_map.borrow_mut()
    }

    pub(crate) fn resolved_module_set(&self) -> Ref<'_, HashSet<ResolvedModule>> {
        self.resolved_module_set.borrow()
    }

    /// <https://html.spec.whatwg.org/multipage/#add-module-to-resolved-module-set>
    pub(crate) fn add_module_to_resolved_module_set(
        &self,
        base_url: &str,
        specifier: &str,
        specifier_url: Option<ServoUrl>,
    ) {
        // Step 1. Let global be settingsObject's global object.
        // Step 2. If global does not implement Window, then return.
        if self.is::<Window>() {
            // Step 3. Let record be a new specifier resolution record, with serialized base URL
            // set to serializedBaseURL, specifier set to normalizedSpecifier, and specifier as
            // a URL set to asURL.
            let record =
                ResolvedModule::new(base_url.to_owned(), specifier.to_owned(), specifier_url);
            // Step 4. Append record to global's resolved module set.
            self.resolved_module_set.borrow_mut().insert(record);
        }
    }

    /// <https://html.spec.whatwg.org/multipage/#run-steps-after-a-timeout>
    /// TODO: This should end-up being used in the other timer mechanism
    /// integrate as per <https://html.spec.whatwg.org/multipage/#timers:run-steps-after-a-timeout?
    pub(crate) fn run_steps_after_a_timeout<F>(
        &self,
        ordering_identifier: DOMString,
        milliseconds: i64,
        completion_steps: F,
    ) -> i32
    where
        F: 'static + FnOnce(&mut js::context::JSContext, &GlobalScope),
    {
        let ms = milliseconds.max(0) as u64;
        let delay = std::time::Duration::from_millis(ms);

        let (callback, timer_key) = self.with_timers(|timers| {
            // Step 1. Let timerKey be a new unique internal value.
            let timer_key = timers.fresh_runsteps_key();

            // Step 2. Let startTime be the current high resolution time given global.
            let start_time = timers.now_for_runsteps();

            // Step 3. Set global's map of active timers[timerKey] to startTime plus milliseconds.
            let deadline = start_time + delay;
            timers.runsteps_set_active(timer_key, deadline);

            // Step 4. Run the following steps in parallel:
            //   (We schedule a oneshot that will enforce the sub-steps when it fires.)
            let callback = crate::timers::OneshotTimerCallback::RunStepsAfterTimeout {
                // Step 1. timerKey
                timer_key,
                // Step 4. orderingIdentifier
                ordering_id: ordering_identifier,
                // Spec: milliseconds
                milliseconds: ms,
                // Step 4.4 Perform completionSteps.
                completion: Box::new(completion_steps),
            };
            (callback, timer_key)
        });
        let _ = self.schedule_callback(callback, delay);

        // Step 5. Return timerKey.
        timer_key
    }
}

/// Returns the Rust global scope from a JS global object.
#[expect(unsafe_code)]
unsafe fn global_scope_from_global(
    cx: &mut js::context::JSContext,
    global: *mut JSObject,
) -> DomRoot<GlobalScope> {
    unsafe {
        assert!(!global.is_null());
        let clasp = get_object_class(global);
        assert_ne!(
            ((*clasp).flags & (JSCLASS_IS_DOMJSCLASS | JSCLASS_IS_GLOBAL)),
            0
        );
        root_from_object(cx, global).unwrap()
    }
}

/// Returns the Rust global scope from a JS global object.
#[expect(unsafe_code)]
unsafe fn global_scope_from_global_static(global: *mut JSObject) -> DomRoot<GlobalScope> {
    assert!(!global.is_null());
    let clasp = unsafe { get_object_class(global) };

    unsafe {
        assert_ne!(
            ((*clasp).flags & (JSCLASS_IS_DOMJSCLASS | JSCLASS_IS_GLOBAL)),
            0
        );
    }

    root_from_object_static(global).unwrap()
}

#[expect(unsafe_code)]
impl GlobalScopeHelpers<crate::DomTypeHolder> for GlobalScope {
    fn from_current_realm(realm: &'_ mut CurrentRealm) -> DomRoot<Self> {
        GlobalScope::from_current_realm(realm)
    }

    unsafe fn from_object(obj: *mut JSObject) -> DomRoot<Self> {
        unsafe { GlobalScope::from_object(obj) }
    }

    fn from_reflector(reflector: &impl DomObject) -> DomRoot<Self> {
        GlobalScope::from_reflector(reflector)
    }

    fn origin(&self) -> MutableOrigin {
        GlobalScope::origin(self)
    }

    fn incumbent() -> Option<DomRoot<Self>> {
        GlobalScope::incumbent()
    }

    fn perform_a_microtask_checkpoint(&self, cx: &mut js::context::JSContext) {
        GlobalScope::perform_a_microtask_checkpoint(self, cx)
    }

    fn get_url(&self) -> ServoUrl {
        self.get_url()
    }

    fn is_secure_context(&self) -> bool {
        self.is_secure_context()
    }
}

impl OwnerWindow<DomTypeHolder> for GlobalScope {}