script/dom/window/

windowproxy.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::cell::Cell;
use std::ptr::{self, NonNull};
use std::rc::Rc;

use content_security_policy::sandboxing_directive::SandboxingFlagSet;
use dom_struct::dom_struct;
use html5ever::local_name;
use indexmap::map::IndexMap;
use itertools::Either;
use js::JSCLASS_IS_GLOBAL;
use js::context::JSContext;
use js::gc::{HandleId, HandleObject, HandleValue, MutableHandleObject};
use js::glue::{
    CreateWrapperProxyHandler, DeleteWrapperProxyHandler, GetProxyPrivate, GetProxyReservedSlot,
    ProxyTraps, SetProxyReservedSlot,
};
use js::jsapi::{
    GCContext, Handle as RawHandle, HandleId as RawHandleId, HandleObject as RawHandleObject,
    HandleValue as RawHandleValue, JS_DefinePropertyById, JS_DeletePropertyById,
    JS_ForwardSetPropertyTo, JSContext as RawJSContext, JSErrNum, JSITER_HIDDEN, JSITER_OWNONLY,
    JSITER_SYMBOLS, JSObject, JSPROP_ENUMERATE, JSPROP_READONLY, JSTracer,
    MutableHandle as RawMutableHandle, MutableHandleIdVector as RawMutableHandleIdVector,
    MutableHandleObject as RawMutableHandleObject, MutableHandleValue as RawMutableHandleValue,
    ObjectOpResult, PropertyDescriptor, jsid,
};
use js::jsval::{NullValue, PrivateValue, UndefinedValue};
use js::realm::{AutoRealm, CurrentRealm};
use js::rust::wrappers2::{
    AppendToIdVector, GetPropertyKeys, JS_ForwardGetPropertyTo, JS_GetOwnPropertyDescriptorById,
    JS_HasOwnPropertyById, JS_HasPropertyById, JS_TransplantObject, NewWindowProxy, SetWindowProxy,
    int_to_jsid,
};
use js::rust::{Handle, MutableHandle, MutableHandleValue, get_object_class};
use js::typedarray::JSObjectStorage;
use malloc_size_of::{MallocSizeOf, MallocSizeOfOps};
use net_traits::ReferrerPolicy;
use net_traits::request::Referrer;
use script_bindings::cell::DomRefCell;
use script_bindings::codegen::GenericBindings::DissimilarOriginWindowBinding::{
    self, DissimilarOriginWindowMethods,
};
use script_bindings::codegen::GenericBindings::HTMLIFrameElementBinding::HTMLIFrameElementMethods;
use script_bindings::codegen::GenericBindings::WindowBinding::{
    self, GetProtoObject, WindowMethods,
};
use script_bindings::conversions::jsid_to_string;
use script_bindings::proxyhandler::{
    self, cross_origin_get_own_property_helper, cross_origin_own_property_keys,
    cross_origin_property_fallback, cross_origin_set, is_extensible,
    is_platform_object_same_origin, maybe_cross_origin_get_prototype,
    maybe_cross_origin_set_prototype_rawcx, prevent_extensions, report_cross_origin_denial,
    set_property_descriptor,
};
use script_bindings::reflector::{DomObject, MutDomObject, Reflector};
use script_traits::NewPipelineInfo;
use serde::{Deserialize, Serialize};
use servo_base::generic_channel;
use servo_base::generic_channel::GenericSend;
use servo_base::id::{BrowsingContextId, PipelineId, WebViewId};
use servo_constellation_traits::{
    AuxiliaryWebViewCreationRequest, LoadData, LoadOrigin, NavigationHistoryBehavior,
    ScriptToConstellationMessage, TargetSnapshotParams,
};
use servo_url::{ImmutableOrigin, OriginSnapshot, ServoUrl};
use storage_traits::webstorage_thread::WebStorageThreadMsg;
use style::attr::parse_integer;

use crate::DomTypeHolder;
use crate::dom::bindings::conversions::{ToJSValConvertible, root_from_handleobject};
use crate::dom::bindings::error::{Error, Fallible};
use crate::dom::bindings::inheritance::Castable;
use crate::dom::bindings::reflector::DomGlobal;
use crate::dom::bindings::root::{Dom, DomRoot};
use crate::dom::bindings::settings_stack::maybe_entry_global;
use crate::dom::bindings::str::{DOMString, USVString};
use crate::dom::bindings::trace::JSTraceable;
use crate::dom::bindings::utils::get_array_index_from_id;
use crate::dom::dissimilaroriginwindow::DissimilarOriginWindow;
use crate::dom::document::Document;
use crate::dom::element::Element;
use crate::dom::globalscope::GlobalScope;
use crate::dom::node::node::NodeTraits;
use crate::dom::window::Window;
use crate::event_loop::script_thread::{ScriptThread, with_script_thread};
use crate::event_loop::script_window_proxies::ScriptWindowProxies;
use crate::navigation::navigate;

#[dom_struct]
// NOTE: the browsing context for a window is managed in two places:
// here, in script, but also in the constellation. The constellation
// manages the session history, which in script is accessed through
// History objects, messaging the constellation.
pub(crate) struct WindowProxy {
    /// The JS WindowProxy object.
    /// Unlike other reflectors, we mutate this field because
    /// we have to brain-transplant the reflector when the WindowProxy
    /// changes Window.
    reflector: Reflector,

    /// The id of the browsing context.
    /// In the case that this is a nested browsing context, this is the id
    /// of the container.
    #[no_trace]
    browsing_context_id: BrowsingContextId,

    // https://html.spec.whatwg.org/multipage/#opener-browsing-context
    #[no_trace]
    opener: Option<BrowsingContextId>,

    /// The frame id of the top-level ancestor browsing context.
    /// In the case that this is a top-level window, this is our id.
    #[no_trace]
    webview_id: WebViewId,

    /// The name of the browsing context (sometimes, but not always,
    /// equal to the name of a container element)
    name: DomRefCell<DOMString>,
    /// The pipeline id of the currently active document.
    /// May be None, when the currently active document is in another script thread.
    /// We do not try to keep the pipeline id for documents in other threads,
    /// as this would require the constellation notifying many script threads about
    /// the change, which could be expensive.
    #[no_trace]
    currently_active: Cell<Option<PipelineId>>,

    /// Has the browsing context been discarded?
    discarded: Cell<bool>,

    /// Has the browsing context been disowned?
    disowned: Cell<bool>,

    /// <https://html.spec.whatwg.org/multipage/#is-closing>
    is_closing: Cell<bool>,

    /// If the containing `<iframe>` of this [`WindowProxy`] is from a same-origin page,
    /// this will be the [`Element`] of the `<iframe>` element in the realm of the
    /// parent page. Otherwise, it is `None`.
    frame_element: Option<Dom<Element>>,

    /// The parent browsing context's window proxy, if this is a nested browsing context
    parent: Option<Dom<WindowProxy>>,

    /// <https://html.spec.whatwg.org/multipage/#delaying-load-events-mode>
    delaying_load_events_mode: Cell<bool>,

    /// The creator browsing context's url.
    #[no_trace]
    creator_url: Option<ServoUrl>,

    /// The creator browsing context's origin.
    #[no_trace]
    creator_origin: Option<ImmutableOrigin>,

    /// The window proxies the script thread knows.
    #[conditional_malloc_size_of]
    script_window_proxies: Rc<ScriptWindowProxies>,
}

impl WindowProxy {
    fn new_inherited(
        browsing_context_id: BrowsingContextId,
        webview_id: WebViewId,
        currently_active: Option<PipelineId>,
        frame_element: Option<&Element>,
        parent: Option<&WindowProxy>,
        opener: Option<BrowsingContextId>,
        creator: CreatorBrowsingContextInfo,
    ) -> WindowProxy {
        let name = frame_element.map_or(DOMString::new(), |e| {
            e.get_string_attribute(&local_name!("name"))
        });
        WindowProxy {
            reflector: Reflector::new(),
            browsing_context_id,
            webview_id,
            name: DomRefCell::new(name),
            currently_active: Cell::new(currently_active),
            discarded: Cell::new(false),
            disowned: Cell::new(false),
            is_closing: Cell::new(false),
            frame_element: frame_element.map(Dom::from_ref),
            parent: parent.map(Dom::from_ref),
            delaying_load_events_mode: Cell::new(false),
            opener,
            creator_url: creator.url,
            creator_origin: creator.origin,
            script_window_proxies: ScriptThread::window_proxies(),
        }
    }

    #[expect(unsafe_code)]
    #[expect(clippy::too_many_arguments)]
    pub(crate) fn new(
        cx: &mut JSContext,
        window: &Window,
        browsing_context_id: BrowsingContextId,
        webview_id: WebViewId,
        frame_element: Option<&Element>,
        parent: Option<&WindowProxy>,
        opener: Option<BrowsingContextId>,
        creator: CreatorBrowsingContextInfo,
    ) -> DomRoot<WindowProxy> {
        unsafe {
            let handler = window.windowproxy_handler();

            let window_jsobject = window.reflector().get_jsobject();
            assert!(!window_jsobject.get().is_null());
            assert_ne!(
                ((*get_object_class(window_jsobject.get())).flags & JSCLASS_IS_GLOBAL),
                0
            );

            let mut realm = AutoRealm::new_from_handle(cx, window_jsobject);
            let cx = &mut realm;

            // Create a new window proxy.
            rooted!(&in(cx) let js_proxy = handler.new_window_proxy(cx, window_jsobject));
            assert!(!js_proxy.is_null());

            // Create a new browsing context.

            let current = Some(window.upcast::<GlobalScope>().pipeline_id());
            let window_proxy = Box::new(WindowProxy::new_inherited(
                browsing_context_id,
                webview_id,
                current,
                frame_element,
                parent,
                opener,
                creator,
            ));

            // The window proxy owns the browsing context.
            // When we finalize the window proxy, it drops the browsing context it owns.
            SetProxyReservedSlot(
                js_proxy.get(),
                0,
                &PrivateValue(&raw const (*window_proxy) as *const libc::c_void),
            );

            // Notify the JS engine about the new window proxy binding.
            SetWindowProxy(cx, window_jsobject, js_proxy.handle());

            // Set the reflector.
            debug!(
                "Initializing reflector of {:p} to {:p}.",
                window_proxy,
                js_proxy.get()
            );
            window_proxy
                .reflector
                .init_reflector::<WindowProxy>(js_proxy.get());
            DomRoot::from_ref(&*Box::into_raw(window_proxy))
        }
    }

    #[expect(unsafe_code)]
    pub(crate) fn new_dissimilar_origin(
        cx: &mut JSContext,
        global_to_clone_from: &GlobalScope,
        browsing_context_id: BrowsingContextId,
        webview_id: WebViewId,
        parent: Option<&WindowProxy>,
        opener: Option<BrowsingContextId>,
        creator: CreatorBrowsingContextInfo,
    ) -> DomRoot<WindowProxy> {
        unsafe {
            // Create a new browsing context.
            let window_proxy = Box::new(WindowProxy::new_inherited(
                browsing_context_id,
                webview_id,
                None,
                None,
                parent,
                opener,
                creator,
            ));

            // Create a new dissimilar-origin window.
            let window = DissimilarOriginWindow::new(cx, global_to_clone_from, &window_proxy);
            let window_jsobject = window.reflector().get_jsobject();
            assert!(!window_jsobject.get().is_null());
            assert_ne!(
                ((*get_object_class(window_jsobject.get())).flags & JSCLASS_IS_GLOBAL),
                0
            );

            let mut realm = AutoRealm::new_from_handle(cx, window_jsobject);
            let cx = &mut realm;

            // Create a new window proxy.
            let handler = WindowProxyHandler::proxy_handler();
            rooted!(&in(cx) let js_proxy = handler.new_window_proxy(cx, window_jsobject));
            assert!(!js_proxy.is_null());

            // The window proxy owns the browsing context.
            // When we finalize the window proxy, it drops the browsing context it owns.
            SetProxyReservedSlot(
                js_proxy.get(),
                0,
                &PrivateValue(&raw const (*window_proxy) as *const libc::c_void),
            );

            // Notify the JS engine about the new window proxy binding.
            SetWindowProxy(cx, window_jsobject, js_proxy.handle());

            // Set the reflector.
            debug!(
                "Initializing reflector of {:p} to {:p}.",
                window_proxy,
                js_proxy.get()
            );
            window_proxy
                .reflector
                .init_reflector::<WindowProxy>(js_proxy.get());
            DomRoot::from_ref(&*Box::into_raw(window_proxy))
        }
    }

    /// <https://html.spec.whatwg.org/multipage/#auxiliary-browsing-context>
    fn create_auxiliary_browsing_context(
        &self,
        cx: &mut JSContext,
        name: DOMString,
        noopener: bool,
    ) -> Option<DomRoot<WindowProxy>> {
        let (response_sender, response_receiver) = generic_channel::channel().unwrap();
        let window = self
            .currently_active
            .get()
            .and_then(ScriptThread::find_document)
            .map(|doc| DomRoot::from_ref(doc.window()))
            .unwrap();

        let document = self
            .currently_active
            .get()
            .and_then(ScriptThread::find_document)
            .expect("A WindowProxy creating an auxiliary to have an active document");

        // <https://html.spec.whatwg.org/multipage/#navigable-target-names>
        // > If the user agent has been configured such that in this instance it
        // > will create a new top-level traversable
        // >
        // Step 9. If sandboxingFlagSet's sandbox propagates to auxiliary browsing
        //   contexts flag is set, then all the flags that are set in sandboxingFlagSet
        // must be set in chosen's active browsing context's popup sandboxing flag set.
        let sandboxing_flag_set = document.active_sandboxing_flag_set();
        let propagate_sandbox = sandboxing_flag_set
            .contains(SandboxingFlagSet::SANDBOX_PROPOGATES_TO_AUXILIARY_BROWSING_CONTEXTS_FLAG);
        let sandboxing_flag_set = if propagate_sandbox {
            sandboxing_flag_set
        } else {
            SandboxingFlagSet::empty()
        };

        let blank_url = ServoUrl::parse("about:blank").ok().unwrap();
        let mut load_data = LoadData::new(
            LoadOrigin::Script(document.origin().snapshot()),
            blank_url,
            Some(document.base_url()),
            // This has the effect of ensuring that the new `about:blank` URL has the
            // same origin as the `Document` that is creating the new browsing context.
            Some(window.pipeline_id()),
            document.global().get_referrer(),
            document.get_referrer_policy(),
            None, // Doesn't inherit secure context
            None,
            false,
            sandboxing_flag_set,
        );
        load_data.is_initial_about_blank = true;
        let load_info = AuxiliaryWebViewCreationRequest {
            load_data: load_data.clone(),
            opener_webview_id: window.webview_id(),
            opener_pipeline_id: self.currently_active.get().unwrap(),
            response_sender,
        };
        let constellation_msg = ScriptToConstellationMessage::CreateAuxiliaryWebView(load_info);
        window.send_to_constellation(constellation_msg);

        let response = response_receiver.recv().unwrap()?;
        let new_browsing_context_id = BrowsingContextId::from(response.new_webview_id);
        let new_pipeline_info = NewPipelineInfo {
            parent_info: None,
            new_pipeline_id: response.new_pipeline_id,
            browsing_context_id: new_browsing_context_id,
            webview_id: response.new_webview_id,
            opener: Some(self.browsing_context_id),
            load_data,
            viewport_details: window.viewport_details(),
            user_content_manager_id: response.user_content_manager_id,
            // Use the current `WebView`'s theme initially, but the embedder may
            // change this later.
            embedder_theme: window.embedder_theme(),
            target_snapshot_params: TargetSnapshotParams {
                sandboxing_flags: sandboxing_flag_set,
                iframe_element_referrer_policy: ReferrerPolicy::EmptyString,
            },
            frame_name: None,
        };

        with_script_thread(|script_thread| {
            script_thread.spawn_pipeline(cx, new_pipeline_info);
        });

        let new_window_proxy = ScriptThread::find_document(response.new_pipeline_id)
            .and_then(|doc| doc.browsing_context())?;
        if !name.eq_ignore_ascii_case("_blank") {
            new_window_proxy.set_name(name);
        }
        if noopener {
            new_window_proxy.disown();
        } else {
            // After creating a new auxiliary browsing context and document,
            // the session storage is copied over.
            // See https://html.spec.whatwg.org/multipage/#the-sessionstorage-attribute

            let (sender, receiver) = generic_channel::channel().unwrap();

            let msg = WebStorageThreadMsg::Clone {
                sender,
                src: window.window_proxy().webview_id(),
                dest: response.new_webview_id,
            };

            GenericSend::send(document.global().storage_threads(), msg).unwrap();
            receiver.recv().unwrap();
        }
        Some(new_window_proxy)
    }

    /// <https://html.spec.whatwg.org/multipage/#delaying-load-events-mode>
    pub(crate) fn start_delaying_load_events_mode(&self) {
        self.delaying_load_events_mode.set(true);
    }

    /// <https://html.spec.whatwg.org/multipage/#delaying-load-events-mode>
    pub(crate) fn stop_delaying_load_events_mode(&self) {
        self.delaying_load_events_mode.set(false);
    }

    // https://html.spec.whatwg.org/multipage/#disowned-its-opener
    pub(crate) fn disown(&self) {
        self.disowned.set(true);
    }

    /// <https://html.spec.whatwg.org/multipage/#dom-window-close>
    /// Step 3.1, set BCs `is_closing` to true.
    pub(crate) fn close(&self) {
        self.is_closing.set(true);
    }

    /// <https://html.spec.whatwg.org/multipage/#is-closing>
    pub(crate) fn is_closing(&self) -> bool {
        self.is_closing.get()
    }

    // https://html.spec.whatwg.org/multipage/#dom-opener
    pub(crate) fn opener(&self, cx: &mut CurrentRealm, mut retval: MutableHandleValue) {
        if self.disowned.get() {
            return retval.set(NullValue());
        }
        let opener_id = match self.opener {
            Some(opener_browsing_context_id) => opener_browsing_context_id,
            None => return retval.set(NullValue()),
        };
        let parent_browsing_context = self.parent.as_deref();
        let opener_proxy = match self.script_window_proxies.find_window_proxy(opener_id) {
            Some(window_proxy) => window_proxy,
            None => {
                let sender_pipeline_id = self.currently_active().unwrap();
                match ScriptThread::get_top_level_for_browsing_context(
                    self.webview_id(),
                    sender_pipeline_id,
                    opener_id,
                ) {
                    Some(opener_top_id) => {
                        let global_to_clone_from = GlobalScope::from_current_realm(cx);
                        let creator =
                            CreatorBrowsingContextInfo::from(parent_browsing_context, None);
                        WindowProxy::new_dissimilar_origin(
                            cx,
                            &global_to_clone_from,
                            opener_id,
                            opener_top_id,
                            None,
                            None,
                            creator,
                        )
                    },
                    None => return retval.set(NullValue()),
                }
            },
        };
        if opener_proxy.is_browsing_context_discarded() {
            return retval.set(NullValue());
        }
        opener_proxy.to_jsval(cx, retval);
    }

    // https://html.spec.whatwg.org/multipage/#window-open-steps
    pub(crate) fn open(
        &self,
        cx: &mut JSContext,
        url: USVString,
        target: DOMString,
        features: DOMString,
    ) -> Fallible<Option<DomRoot<WindowProxy>>> {
        // Note: this does not map to the spec,
        // but it does prevent a panic at the constellation because the browsing context
        // has already been discarded.
        // See issue: #39716 for the original problem,
        // and https://github.com/whatwg/html/issues/11797 for a discussion at the level of the spec.
        if self.discarded.get() {
            return Ok(None);
        }
        // Step 2. Let sourceDocument be the entry global object's associated Document.
        //
        // It's possible to end up in a situation where JS code is executing but
        // we have not had a chance to push an entry global (e.g. via WASM instantiation).
        // If that happens, fall back to the active document of this browsing context.
        let source_document = maybe_entry_global()
            .map(|global| global.as_window().Document())
            .or_else(|| self.document())
            .expect("Must have an entry global or active document");
        // Step 4. If url is not the empty string:
        let url_record = if !url.is_empty() {
            // Step 4.1. Set urlRecord to the result of encoding-parsing a URL given url, relative to sourceDocument.
            let Ok(url) = source_document.encoding_parse_a_url(&url) else {
                // Step 4.2. If urlRecord is failure, then throw a "SyntaxError" DOMException.
                return Err(Error::Syntax(Some(format!(
                    "Error parsing URL '{url}' relative to '{}'",
                    source_document.url()
                ))));
            };
            Some(url)
        } else {
            // Step 3. Let urlRecord be null.
            None
        };
        // Step 5. If target is the empty string, then set target to "_blank".
        let non_empty_target = if target.is_empty() {
            DOMString::from_static("_blank")
        } else {
            target
        };
        // Step 6. Let tokenizedFeatures be the result of tokenizing features.
        let tokenized_features = tokenize_open_features(features);
        // Step 7 - 8.
        // If tokenizedFeatures["noreferrer"] exists, then set noreferrer to
        // the result of parsing tokenizedFeatures["noreferrer"] as a boolean feature.
        let noreferrer = parse_open_feature_boolean(&tokenized_features, "noreferrer");

        // Step 9. Let noopener be the result of getting noopener for window
        // open with sourceDocument, tokenizedFeatures, and urlRecord.
        let noopener = if noreferrer {
            true
        } else {
            parse_open_feature_boolean(&tokenized_features, "noopener")
        };
        // (TODO) Step 10. Remove tokenizedFeatures["noopener"] and tokenizedFeatures["noreferrer"].

        // (TODO) Step 11. Let referrerPolicy be the empty string.
        // (TODO) Step 12. If noreferrer is true, then set referrerPolicy to "no-referrer".

        // Step 13 - 14
        // Let targetNavigable and windowType be the result of applying the rules for
        // choosing a navigable given target, sourceDocument's node navigable, and noopener.
        // If targetNavigable is null, then return null.
        let (chosen, new) = match self.choose_a_navigable(cx, non_empty_target, noopener) {
            (Some(chosen), new) => (chosen, new),
            (None, _) => return Ok(None),
        };
        // TODO Step 15.2, Set up browsing context features for targetNavigable's
        // active browsing context given tokenizedFeatures.
        let target_document = match chosen.document() {
            Some(target_document) => target_document,
            None => return Ok(None),
        };
        let has_trustworthy_ancestor_origin = if new {
            target_document.has_trustworthy_ancestor_or_current_origin()
        } else {
            false
        };
        let target_window = target_document.window();
        // Step 15.3. If urlRecord is null, then set urlRecord to a URL record representing about:blank.
        let url_record = url_record.unwrap_or(ServoUrl::parse("about:blank").unwrap());
        // Step 15.4. If urlRecord matches about:blank, then perform the URL and history update steps given targetNavigable's active document and urlRecord.
        //
        // This happened in the constellation as part of creating the auxiliary browsing context.
        if !url_record.matches_about_blank() {
            let referrer = if noreferrer {
                Referrer::NoReferrer
            } else {
                target_window.as_global_scope().get_referrer()
            };
            // Propagate CSP list and about-base-url from opener to new document
            let csp_list = source_document.get_csp_list().clone();
            target_document.set_csp_list(csp_list);

            // Step 15.5 Otherwise, navigate targetNavigable to urlRecord using sourceDocument,
            // with referrerPolicy set to referrerPolicy and exceptionsEnabled set to true.
            // FIXME: referrerPolicy may not be used properly here. exceptionsEnabled not used.
            let mut load_data = LoadData::new(
                LoadOrigin::Script(source_document.origin().snapshot()),
                url_record,
                target_document.about_base_url(),
                Some(target_window.pipeline_id()),
                referrer,
                target_document.get_referrer_policy(),
                Some(target_window.as_global_scope().is_secure_context()),
                Some(target_document.insecure_requests_policy()),
                has_trustworthy_ancestor_origin,
                target_document.creation_sandboxing_flag_set_considering_parent_iframe(),
            );

            // Handle javascript: URLs specially to report CSP violations to the source window
            // https://html.spec.whatwg.org/multipage/#navigate-to-a-javascript:-url
            if load_data.url.scheme() == "javascript" {
                let existing_global = source_document.global();

                // Check CSP and report violations to the source (existing) window
                if !ScriptThread::can_navigate_to_javascript_url(
                    cx,
                    &existing_global,
                    target_window.as_global_scope(),
                    &mut load_data,
                    None,
                ) {
                    // CSP blocked the navigation, don't proceed
                    return Ok(target_document.browsing_context());
                }
            }

            let history_handling = if new {
                NavigationHistoryBehavior::Replace
            } else {
                NavigationHistoryBehavior::Push
            };
            navigate(cx, target_window, history_handling, false, load_data);
        }
        // Step 17 (Dis-owning has been done in create_auxiliary_browsing_context).
        if noopener {
            return Ok(None);
        }
        // Step 18
        Ok(target_document.browsing_context())
    }

    /// <https://html.spec.whatwg.org/multipage/#the-rules-for-choosing-a-navigable>
    pub(crate) fn choose_a_navigable(
        &self,
        cx: &mut JSContext,
        name: DOMString,
        noopener: bool,
    ) -> (Option<DomRoot<WindowProxy>>, bool) {
        // Step 1. Let chosen be null.
        // Step 2. Let windowType be "existing or none".
        // Step 3. Let sandboxingFlagSet be currentNavigable's active document's active
        // sandboxing flag set.
        // TODO: Implement this.

        let chosen = if name.is_empty() || name.eq_ignore_ascii_case("_self") {
            // Step 4. If name is the empty string or an ASCII case-insensitive match for
            // "_self", then set chosen to currentNavigable.
            Some((Some(DomRoot::from_ref(self)), false))
        } else if name.eq_ignore_ascii_case("_parent") {
            // Step 5. Otherwise, if name is an ASCII case-insensitive match for
            // "_parent", set chosen to currentNavigable's parent, if any, and
            // currentNavigable otherwise.
            Some(
                self.parent()
                    .map(|parent| (Some(DomRoot::from_ref(parent)), false))
                    .unwrap_or_else(|| (Some(DomRoot::from_ref(self)), false)),
            )
        } else if name.eq_ignore_ascii_case("_top") {
            // Step 6. Otherwise, if name is an ASCII case-insensitive match for "_top",
            // set chosen to currentNavigable's traversable navigable.
            Some((Some(DomRoot::from_ref(self.top())), false))
        } else if !name.eq_ignore_ascii_case("_blank") {
            // Step 7. Otherwise, if name is not an ASCII case-insensitive match for
            // "_blank" and noopener is false, then set chosen to the result of finding a
            // navigable by target name given name and currentNavigable.
            //
            // Note: The noopener==false condition here seems to break WPT tests and
            // is likely a specification bug.
            // See <https://github.com/whatwg/html/issues/12839>
            self.find_navigable_by_target_name(&name)
                .map(|proxy| (Some(proxy), false))
        } else {
            None
        };

        if let Some(chosen) = chosen {
            return chosen;
        }

        // Step 8. If chosen is null, then a new top-level traversable is being requested,
        // and what happens depends on the user agent's configuration and abilities — it
        // is determined by the rules given for the first applicable option from the
        // following list:
        (
            self.create_auxiliary_browsing_context(cx, name, noopener),
            true,
        )
    }

    /// <https://html.spec.whatwg.org/multipage/#find-a-navigable-by-target-name>
    fn find_navigable_by_target_name(&self, name: &DOMString) -> Option<DomRoot<WindowProxy>> {
        // Step 1. Let currentDocument be currentNavigable's active document.
        //
        // Step 2. Let sourceSnapshotParams be the result of snapshotting source snapshot
        // params given currentDocument.
        // TODO: This is unimplemented.
        //
        // Step 3. Let subtreesToSearch be an implementation-defined choice of one of the
        // following:
        //     - « currentNavigable's traversable navigable, currentNavigable »
        //     - the inclusive ancestor navigables of currentDocument
        //
        // From <https://github.com/whatwg/html/issues/10848>:
        // > WebKit and Chromium search the requesting window's subtree then search from
        // > the top. Firefox iterates and searches from each ancestor. If there's a way to
        // > express in the spec that the implementation-defined behavior is fixed for the
        // > instance of the user agent, then that'd be appropriate here.
        //
        // We use the Webkit and Chrome approach here and the reversal is done here
        // rather than below.
        let top = self.top();
        let subtrees_to_search = if top != self {
            Either::Left([self, top])
        } else {
            Either::Right([self])
        };

        // Step 4. For each subtreeToSearch of subtreesToSearch, in reverse order:
        for subtree_to_search in subtrees_to_search.into_iter() {
            // Step 4.1. Let documentToSearch be subtreeToSearch's active document.
            // Step 4.2. For each navigable of the inclusive descendant navigables of
            // documentToSearch:
            if let Some(result) =
                subtree_to_search.find_navigable_by_target_name_in_descendants(name)
            {
                return Some(result);
            }
        }

        // Step 5. Let currentTopLevelBrowsingContext be currentNavigable's active
        // browsing context's top-level browsing context.
        // Step 6. Let group be currentTopLevelBrowsingContext's group.
        //
        // TODO: Servo doesn't have a concept of the browsing context group in script, so
        // we just look through all top-level WindowProxy instances.
        let mut top_level_window_proxies = self.script_window_proxies.top_level_window_proxies();

        // Step 7. For each topLevelBrowsingContext of group's browsing context set, in an
        // implementation-defined order (the user agent should pick a consistent ordering,
        // such as the most recently opened, most recently focused, or more closely
        // related):
        //
        // Sorting by `BrowsingContextId` is an attempt to make the order consistent.
        // This also ensures that newer `BrowsingContextId`s are sorted first.
        top_level_window_proxies
            .sort_by_key(|proxy| std::cmp::Reverse(proxy.browsing_context_id()));

        for window_proxy in top_level_window_proxies {
            // Step 7.1. If currentTopLevelBrowsingContext is topLevelBrowsingContext, then
            // continue.
            if &*window_proxy == top {
                continue;
            }
            // Step 7.2. Let documentToSearch be topLevelBrowsingContext's active document.
            // Step 7.3. For each navigable of the inclusive descendant navigables of
            // documentToSearch:
            //
            // Step 7.3.1 If currentNavigable's active browsing context is not familiar
            // with navigable's active browsing context, then continue.
            //
            // TODO: Servo does not implement the concept of "familiar with".
            // See: <https://html.spec.whatwg.org/multipage/#familiar-with>
            // TODO: Properly support navigables in other script threads and with
            // dissimilar origins, which requires that they be accessible here and
            // WindowProxy::get_name() returns something useful.
            //
            // Step 7.3.2. If currentNavigable is not allowed by sandboxing to navigate
            // navigable given sourceSnapshotParams, then optionally continue.
            // Step 7.3.3 If navigable's target name is name, then return navigable.
            // These steps are handled by `find_navigable_by_target_name_in_descendants`.
            if let Some(result) = window_proxy.find_navigable_by_target_name_in_descendants(name) {
                return Some(result);
            }
        }

        // Step 8. Return null.
        None
    }

    /// <https://html.spec.whatwg.org/multipage/#find-a-navigable-by-target-name> step 4 and 7 substeps.
    fn find_navigable_by_target_name_in_descendants(
        &self,
        name: &DOMString,
    ) -> Option<DomRoot<WindowProxy>> {
        // Never traverse or return a `WindowProxy` with a discarded browsing context.
        if self.is_browsing_context_discarded() {
            return None;
        }

        // Step 4.2.1 If currentNavigable is not allowed by sandboxing to navigate
        // navigable given sourceSnapshotParams, then optionally continue.
        // TODO: This is unimplemented.

        // Step 4.2.2. If navigable's target name is name, then return navigable.
        if self.get_name() == *name {
            return Some(DomRoot::from_ref(self));
        }

        let document = self.document()?;
        let iframes: Vec<_> = document.iframes().iter().collect();
        iframes.iter().find_map(|iframe| {
            iframe
                .browsing_context_id()
                .and_then(|browsing_context_id| {
                    self.script_window_proxies
                        .find_window_proxy(browsing_context_id)?
                        .find_navigable_by_target_name_in_descendants(name)
                })
        })
    }

    pub(crate) fn is_auxiliary(&self) -> bool {
        self.opener.is_some()
    }

    pub(crate) fn discard_browsing_context(&self) {
        self.discarded.set(true);
    }

    pub(crate) fn is_browsing_context_discarded(&self) -> bool {
        self.discarded.get()
    }

    pub(crate) fn browsing_context_id(&self) -> BrowsingContextId {
        self.browsing_context_id
    }

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

    /// If the containing `<iframe>` of this [`WindowProxy`] is from a same-origin page,
    /// this will return an [`Element`] of the `<iframe>` element in the realm of the parent
    /// page.
    pub(crate) fn frame_element(&self) -> Option<&Element> {
        self.frame_element.as_deref()
    }

    pub(crate) fn document(&self) -> Option<DomRoot<Document>> {
        self.currently_active
            .get()
            .and_then(ScriptThread::find_document)
    }

    pub(crate) fn parent(&self) -> Option<&WindowProxy> {
        self.parent.as_deref()
    }

    pub(crate) fn top(&self) -> &WindowProxy {
        let mut result = self;
        while let Some(parent) = result.parent() {
            result = parent;
        }
        result
    }

    pub(crate) fn document_origin(&self) -> Option<OriginSnapshot> {
        let pipeline_id = self.currently_active()?;
        let (result_sender, result_receiver) = generic_channel::channel().unwrap();
        self.global()
            .script_to_constellation_chan()
            .send(ScriptToConstellationMessage::GetDocumentOrigin(
                pipeline_id,
                result_sender,
            ))
            .ok()?;
        result_receiver.recv().ok()?
    }

    pub(crate) fn internal_ancestor_origin_objects_list(&self) -> Option<Vec<ImmutableOrigin>> {
        let pipeline_id = self.currently_active()?;
        let (result_sender, result_receiver) = generic_channel::channel().unwrap();
        self.global()
            .script_to_constellation_chan()
            .send(
                ScriptToConstellationMessage::GetInternalAncestorOriginObjectsList(
                    pipeline_id,
                    result_sender,
                ),
            )
            .ok()?;
        result_receiver.recv().ok()?
    }

    /// <https://html.spec.whatwg.org/multipage/#internal-ancestor-origin-objects-list-creation-steps>
    pub(crate) fn parent_origin_and_internal_ancestor_origin_objects_list(
        &self,
    ) -> Option<(OriginSnapshot, Vec<ImmutableOrigin>)> {
        if let Some(frame_element) = self.frame_element() {
            let parent_document = frame_element.owner_document();
            // Step 4. Assert: parentDoc is fully active.
            // TODO(47417): Once "creating a new browsing context" properly exists, remove this check
            if !parent_document.is_fully_active() {
                return None;
            }
            Some((
                parent_document.origin().snapshot(),
                parent_document
                    .internal_ancestor_origin_objects_list()
                    .clone()
                    .expect("Must always be fully active"),
            ))
        } else if let Some(parent_proxy) = self.parent() {
            // Step 4. Assert: parentDoc is fully active.
            assert!(parent_proxy.currently_active().is_some());

            let origin = parent_proxy
                .document_origin()
                .expect("Must always be active");
            let list = parent_proxy
                .internal_ancestor_origin_objects_list()
                .expect("Must always be active");
            Some((origin, list))
        } else {
            None
        }
    }

    #[expect(unsafe_code)]
    /// Change the Window that this WindowProxy resolves to.
    // TODO: support setting the window proxy to a dummy value,
    // to handle the case when the active document is in another script thread.
    fn set_window(&self, cx: &mut JSContext, window: &GlobalScope) {
        unsafe {
            debug!("Setting window of {:p}.", self);

            let window_jsobject = window.reflector().get_jsobject();
            let old_js_proxy = self.reflector.get_jsobject();
            assert!(!window_jsobject.get().is_null());
            assert_ne!(
                ((*get_object_class(window_jsobject.get())).flags & JSCLASS_IS_GLOBAL),
                0
            );

            let mut realm = AutoRealm::new_from_handle(cx, window_jsobject);
            let cx = &mut realm;

            // The old window proxy no longer owns this browsing context.
            SetProxyReservedSlot(old_js_proxy.get(), 0, &PrivateValue(ptr::null_mut()));

            // Brain transplant the window proxy. Brain transplantation is
            // usually done to move a window proxy between compartments, but
            // that's not what we are doing here. We need to do this to retarget
            // the proxy at a different global without updating its identity.
            rooted!(&in(cx) let new_js_proxy = WindowProxyHandler::proxy_handler().new_window_proxy(cx, window_jsobject));
            // Explicitly set this slot to a null pointer in case a GC occurs before we
            // are ready to set it to a real value.
            SetProxyReservedSlot(new_js_proxy.get(), 0, &PrivateValue(ptr::null_mut()));
            debug!(
                "Transplanting proxy from {:p} to {:p}.",
                old_js_proxy.get(),
                new_js_proxy.get()
            );
            rooted!(&in(cx) let new_js_proxy = JS_TransplantObject(cx, old_js_proxy, new_js_proxy.handle()));
            debug!("Transplanted proxy is {:p}.", new_js_proxy.get());

            // Transfer ownership of this browsing context from the old window proxy to the new one.
            SetProxyReservedSlot(
                new_js_proxy.get(),
                0,
                &PrivateValue(self as *const _ as *const libc::c_void),
            );

            // Notify the JS engine about the new window proxy binding.
            SetWindowProxy(cx, window_jsobject, new_js_proxy.handle());

            // Update the reflector.
            debug!(
                "Setting reflector of {:p} to {:p}.",
                self,
                new_js_proxy.get()
            );
            self.reflector.rootable().set(new_js_proxy.get());
        }
    }

    pub(crate) fn set_pipeline_id(&self, pipeline_id: PipelineId) {
        self.currently_active.set(Some(pipeline_id));
    }

    pub(crate) fn set_currently_active(&self, cx: &mut JSContext, window: &Window) {
        if let Some(pipeline_id) = self.currently_active() &&
            pipeline_id == window.pipeline_id()
        {
            return debug!(
                "Attempt to set the currently active window to the currently active window."
            );
        }

        let global_scope = window.as_global_scope();
        self.set_window(cx, global_scope);
        self.currently_active.set(Some(global_scope.pipeline_id()));
    }

    pub(crate) fn unset_currently_active(&self, cx: &mut JSContext) {
        if self.currently_active().is_none() {
            return debug!(
                "Attempt to unset the currently active window on a windowproxy that does not have one."
            );
        }
        let globalscope = self.global();
        let window = DissimilarOriginWindow::new(cx, &globalscope, self);
        self.set_window(cx, window.upcast());
        self.currently_active.set(None);
    }

    pub(crate) fn currently_active(&self) -> Option<PipelineId> {
        self.currently_active.get()
    }

    pub(crate) fn get_name(&self) -> DOMString {
        self.name.borrow().clone()
    }

    pub(crate) fn set_name(&self, name: DOMString) {
        *self.name.borrow_mut() = name;
    }
}

/// A browsing context can have a creator browsing context, the browsing context that
/// was responsible for its creation. If a browsing context has a parent browsing context,
/// then that is its creator browsing context. Otherwise, if the browsing context has an
/// opener browsing context, then that is its creator browsing context. Otherwise, the
/// browsing context has no creator browsing context.
///
/// If a browsing context A has a creator browsing context, then the Document that was the
/// active document of that creator browsing context at the time A was created is the creator
/// Document.
///
/// See: <https://html.spec.whatwg.org/multipage/#creating-browsing-contexts>
#[derive(Debug, Deserialize, Serialize)]
pub(crate) struct CreatorBrowsingContextInfo {
    /// Creator document URL.
    url: Option<ServoUrl>,

    /// Creator document origin.
    origin: Option<ImmutableOrigin>,
}

impl CreatorBrowsingContextInfo {
    pub(crate) fn from(
        parent: Option<&WindowProxy>,
        opener: Option<&WindowProxy>,
    ) -> CreatorBrowsingContextInfo {
        let creator = match (parent, opener) {
            (Some(parent), _) => parent.document(),
            (None, Some(opener)) => opener.document(),
            (None, None) => None,
        };

        let url = creator.as_deref().map(|document| document.url());
        let origin = creator
            .as_deref()
            .map(|document| document.origin().immutable().clone());

        CreatorBrowsingContextInfo { url, origin }
    }
}

/// <https://html.spec.whatwg.org/multipage/#concept-window-open-features-tokenize>
fn tokenize_open_features(features: DOMString) -> IndexMap<String, String> {
    let is_feature_sep = |c: char| c.is_ascii_whitespace() || ['=', ','].contains(&c);
    // Step 1
    let mut tokenized_features = IndexMap::new();
    // Step 2
    let features = features.str();
    let mut iter = features.chars();
    let mut cur = iter.next();

    // Step 3
    while cur.is_some() {
        // Step 3.1 & 3.2
        let mut name = String::new();
        let mut value = String::new();
        // Step 3.3
        while let Some(cur_char) = cur {
            if !is_feature_sep(cur_char) {
                break;
            }
            cur = iter.next();
        }
        // Step 3.4
        while let Some(cur_char) = cur {
            if is_feature_sep(cur_char) {
                break;
            }
            name.push(cur_char.to_ascii_lowercase());
            cur = iter.next();
        }
        // Step 3.5
        let normalized_name = String::from(match name.as_ref() {
            "screenx" => "left",
            "screeny" => "top",
            "innerwidth" => "width",
            "innerheight" => "height",
            _ => name.as_ref(),
        });
        // Step 3.6
        while let Some(cur_char) = cur {
            if cur_char == '=' || cur_char == ',' || !is_feature_sep(cur_char) {
                break;
            }
            cur = iter.next();
        }
        // Step 3.7
        if cur.is_some() && is_feature_sep(cur.unwrap()) {
            // Step 3.7.1
            while let Some(cur_char) = cur {
                if !is_feature_sep(cur_char) || cur_char == ',' {
                    break;
                }
                cur = iter.next();
            }
            // Step 3.7.2
            while let Some(cur_char) = cur {
                if is_feature_sep(cur_char) {
                    break;
                }
                value.push(cur_char.to_ascii_lowercase());
                cur = iter.next();
            }
        }
        // Step 3.8
        if !name.is_empty() {
            tokenized_features.insert(normalized_name, value);
        }
    }
    // Step 4
    tokenized_features
}

/// <https://html.spec.whatwg.org/multipage/#concept-window-open-features-parse-boolean>
fn parse_open_feature_boolean(tokenized_features: &IndexMap<String, String>, name: &str) -> bool {
    if let Some(value) = tokenized_features.get(name) {
        // Step 1 & 2
        if value.is_empty() || value == "yes" {
            return true;
        }
        // Step 3 & 4
        if let Ok(int) = parse_integer(value.chars()) {
            return int != 0;
        }
    }
    // Step 5
    false
}

// This is only called from extern functions,
// there's no use using the lifetimed handles here.
// https://html.spec.whatwg.org/multipage/#accessing-other-browsing-contexts
#[expect(unsafe_code)]
#[expect(non_snake_case)]
unsafe fn GetSubframeWindowProxy(
    cx: &mut JSContext,
    proxy: RawHandleObject,
    id: RawHandleId,
) -> Option<(DomRoot<WindowProxy>, u32)> {
    let index = get_array_index_from_id(unsafe { Handle::from_raw(id) });
    if let Some(index) = index {
        let mut slot = UndefinedValue();
        unsafe { GetProxyPrivate(*proxy, &mut slot) };
        rooted!(&in(cx) let target = slot.to_object());
        let script_window_proxies = ScriptThread::window_proxies();
        if let Ok(win) = root_from_handleobject::<Window>(cx, target.handle()) {
            let browsing_context_id = win.window_proxy().browsing_context_id();
            let (result_sender, result_receiver) = generic_channel::channel().unwrap();

            let _ = win.as_global_scope().script_to_constellation_chan().send(
                ScriptToConstellationMessage::GetChildBrowsingContextId(
                    browsing_context_id,
                    index as usize,
                    result_sender,
                ),
            );
            return result_receiver
                .recv()
                .ok()
                .and_then(|maybe_bcid| maybe_bcid)
                .and_then(|id| script_window_proxies.find_window_proxy(id))
                .map(|proxy| (proxy, (JSPROP_ENUMERATE | JSPROP_READONLY) as u32));
        } else if let Ok(win) =
            root_from_handleobject::<DissimilarOriginWindow>(cx, target.handle())
        {
            let browsing_context_id = win.window_proxy().browsing_context_id();
            let (result_sender, result_receiver) = generic_channel::channel().unwrap();

            let _ = win.global().script_to_constellation_chan().send(
                ScriptToConstellationMessage::GetChildBrowsingContextId(
                    browsing_context_id,
                    index as usize,
                    result_sender,
                ),
            );
            return result_receiver
                .recv()
                .ok()
                .and_then(|maybe_bcid| maybe_bcid)
                .and_then(|id| script_window_proxies.find_window_proxy(id))
                .map(|proxy| (proxy, JSPROP_READONLY as u32));
        }
    }

    None
}

#[expect(unsafe_code)]
fn window_proxy_target(proxy: HandleObject) -> *mut JSObject {
    let mut slot = UndefinedValue();
    unsafe { GetProxyPrivate(proxy.as_raw(), &mut slot) };
    slot.to_object()
}

/// <https://html.spec.whatwg.org/multipage/#windowproxy-getownproperty>
#[expect(unsafe_code)]
unsafe extern "C" fn get_own_property_descriptor(
    cx: *mut RawJSContext,
    proxy: RawHandleObject,
    id: RawHandleId,
    property_descriptor: RawMutableHandle<PropertyDescriptor>,
    is_none: *mut bool,
) -> bool {
    let mut cx = unsafe {
        // SAFETY: We are in a SpiderMonkey hook, so it is always safe to convert a raw context into
        // a mozjs context.
        JSContext::from_ptr(NonNull::new(cx).expect("JSContext should not be null in SM hook"))
    };
    let mut cx = CurrentRealm::assert(&mut cx);
    let cx = &mut cx;
    let proxy = unsafe { Handle::from_raw(proxy) };
    let id = unsafe { Handle::from_raw(id) };
    let mut property_descriptor = unsafe { MutableHandle::from_raw(property_descriptor) };
    let is_none = unsafe { &mut *is_none };

    // Step 1. Let W be the value of the [[Window]] internal slot of this.
    // Note: This is the `proxy` argument.

    // Step 2. If P is an array index property name:
    //
    // TODO: The rest of Step 2 is handled in `GetSubframeWindowProxy`, though
    // it does not discriminate between "not an index" and "index out of range"
    // as the specification says we should.
    let window = unsafe { GetSubframeWindowProxy(cx, proxy.into(), id.into()) };
    if let Some((window, attrs)) = window {
        rooted!(&in(cx) let mut val = UndefinedValue());
        window.to_jsval(cx, val.handle_mut());
        set_property_descriptor(property_descriptor, val.handle(), attrs, is_none);
        return true;
    }

    // Step 3. If IsPlatformObjectSameOrigin(W) is true, then return ! OrdinaryGetOwnProperty(W, P).
    rooted!(&in(cx) let target = window_proxy_target(proxy));
    if is_platform_object_same_origin(cx, proxy) {
        return unsafe {
            JS_GetOwnPropertyDescriptorById(cx, target.handle(), id, property_descriptor, is_none)
        };
    }

    let cross_origin_properties = if root_from_handleobject::<Window>(cx, target.handle()).is_ok() {
        unsafe { WindowBinding::CROSS_ORIGIN_PROPERTIES.get() }
    } else if root_from_handleobject::<DissimilarOriginWindow>(cx, target.handle()).is_ok() {
        unsafe { DissimilarOriginWindowBinding::CROSS_ORIGIN_PROPERTIES.get() }
    } else {
        unreachable!("WindowProxy should always be backed by some kind of window");
    };

    // Step 4. Let property be CrossOriginGetOwnPropertyHelper(W, P).
    if !cross_origin_get_own_property_helper(
        cx,
        proxy,
        cross_origin_properties,
        id,
        property_descriptor.reborrow(),
        is_none,
    ) {
        return false;
    }

    // Step 5. If property is not undefined, then return property.
    if !*is_none {
        return true;
    }

    // Step 6. If property is undefined and P is in W's document-tree child navigable target name
    // property set:
    if let Some(named_child_navigable) = named_child_navigable(cx, proxy, id) {
        // Step 6.1. Let value be the active WindowProxy of the named object of W with the name P.
        rooted!(&in(cx) let mut window_proxy_value = UndefinedValue());
        named_child_navigable.to_jsval(cx, window_proxy_value.handle_mut());
        // Step 6.2 Return PropertyDescriptor { [[Value]]: value, [[Enumerable]]: false,
        // [[Writable]]: false, [[Configurable]]: true }.
        set_property_descriptor(
            property_descriptor.reborrow(),
            window_proxy_value.handle(),
            JSPROP_READONLY as u32,
            is_none,
        );
        return true;
    }

    // Step 7. Return ? CrossOriginPropertyFallback(P).
    cross_origin_property_fallback::<DomTypeHolder>(
        cx,
        proxy,
        id,
        property_descriptor.reborrow(),
        is_none,
    )
}

/// <https://html.spec.whatwg.org/multipage/#windowproxy-defineownproperty>
#[expect(unsafe_code)]
unsafe extern "C" fn define_property(
    cx: *mut RawJSContext,
    proxy: RawHandleObject,
    id: RawHandleId,
    desc: RawHandle<PropertyDescriptor>,
    res: *mut ObjectOpResult,
) -> bool {
    let mut cx = unsafe {
        // SAFETY: We are in a SpiderMonkey hook, so it is always safe to convert a raw context into
        // a mozjs context.
        JSContext::from_ptr(NonNull::new(cx).expect("JSContext should not be null in SM hook"))
    };
    let mut cx = CurrentRealm::assert(&mut cx);
    let cx = &mut cx;
    let id = unsafe { Handle::from_raw(id) };
    let proxy = unsafe { Handle::from_raw(proxy) };

    // Step 1. Let W be the value of the [[Window]] internal slot of this.
    // Note: This is the `proxy` argument.

    // Step 2. If IsPlatformObjectSameOrigin(W) is true:
    if is_platform_object_same_origin(cx, proxy) {
        // Step 2.1. If P is an array index property name, return false.
        if get_array_index_from_id(id).is_some() {
            // Spec says to Reject whether this is a supported index or not,
            // since we have no indexed setter or indexed creator.  That means
            // throwing in strict mode (FIXME: Bug 828137), doing nothing in
            // non-strict mode.
            unsafe {
                (*res).code_ = JSErrNum::JSMSG_CANT_DEFINE_WINDOW_ELEMENT as usize;
            }
            return true;
        }

        // Step 2.2. Return ? OrdinaryDefineOwnProperty(W, P, Desc).
        rooted!(&in(cx) let target = window_proxy_target(proxy));
        return unsafe {
            JS_DefinePropertyById(cx.raw_cx(), target.handle().into(), id.into(), desc, res)
        };
    }

    // Step 3. Throw a "SecurityError" DOMException.
    report_cross_origin_denial::<DomTypeHolder>(cx, id, "define")
}

#[expect(unsafe_code)]
unsafe extern "C" fn has(
    cx: *mut RawJSContext,
    proxy: RawHandleObject,
    id: RawHandleId,
    bp: *mut bool,
) -> bool {
    unsafe { has_or_has_own(cx, proxy, id, bp, IncludePrototypes::Yes) }
}

#[expect(unsafe_code)]
unsafe extern "C" fn has_own(
    cx: *mut RawJSContext,
    proxy: RawHandleObject,
    id: RawHandleId,
    bp: *mut bool,
) -> bool {
    unsafe { has_or_has_own(cx, proxy, id, bp, IncludePrototypes::No) }
}

enum IncludePrototypes {
    Yes,
    No,
}

#[expect(unsafe_code)]
unsafe fn has_or_has_own(
    cx: *mut RawJSContext,
    proxy: RawHandleObject,
    id: RawHandleId,
    bp: *mut bool,
    include_prototypes: IncludePrototypes,
) -> bool {
    let mut cx = unsafe { JSContext::from_ptr(ptr::NonNull::new(cx).unwrap()) };
    let mut cx = CurrentRealm::assert(&mut cx);
    let cx = &mut cx;
    let proxy = unsafe { Handle::from_raw(proxy) };
    let id = unsafe { Handle::from_raw(id) };

    let (success, found) = if is_platform_object_same_origin(cx, proxy) {
        let window = unsafe { GetSubframeWindowProxy(cx, proxy.into(), id.into()) };
        if window.is_some() {
            unsafe { *bp = true };
            return true;
        }

        rooted!(&in(cx) let target = window_proxy_target(proxy));
        let mut found = false;
        let success = match include_prototypes {
            IncludePrototypes::Yes => unsafe {
                JS_HasPropertyById(cx, target.handle(), id, &mut found)
            },
            IncludePrototypes::No => unsafe {
                JS_HasOwnPropertyById(cx, target.handle(), id, &mut found)
            },
        };
        (success, found)
    } else {
        rooted!(&in(cx) let mut property_descriptor = PropertyDescriptor::default());
        let mut is_none = false;
        let success = unsafe {
            get_own_property_descriptor(
                cx.raw_cx(),
                proxy.into(),
                id.into(),
                property_descriptor.handle_mut().into(),
                &mut is_none,
            )
        };
        (success, !is_none)
    };

    if !success {
        return false;
    }
    unsafe { *bp = found };
    true
}

/// <https://html.spec.whatwg.org/multipage/#windowproxy-get>
#[expect(unsafe_code)]
unsafe extern "C" fn get(
    cx: *mut RawJSContext,
    proxy: RawHandleObject,
    receiver: RawHandleValue,
    id: RawHandleId,
    return_value: RawMutableHandleValue,
) -> bool {
    let mut cx = unsafe {
        // SAFETY: We are in SM hook
        JSContext::from_ptr(NonNull::new(cx).expect("JSContext should not be null in SM hook"))
    };
    let mut cx = CurrentRealm::assert(&mut cx);
    let cx = &mut cx;
    let proxy = unsafe { Handle::from_raw(proxy) };
    let receiver = unsafe { Handle::from_raw(receiver) };
    let id = unsafe { Handle::from_raw(id) };
    let return_value = unsafe { MutableHandle::from_raw(return_value) };

    // Step 1. Let W be the value of the [[Window]] internal slot of this.
    // Note: This is the `proxy` argument.

    // Step 2. Check if an access between two browsing contexts should be reported, given the
    // current global object's browsing context, W's browsing context, P, and the current settings
    // object.
    // TODO: Implement this.

    // Step 3. If IsPlatformObjectSameOrigin(W) is true, then return ? OrdinaryGet(this, P, Receiver).
    if is_platform_object_same_origin(cx, proxy) {
        let window = unsafe { GetSubframeWindowProxy(cx, proxy.into(), id.into()) };
        if let Some((window, _attrs)) = window {
            window.to_jsval(cx, return_value);
            return true;
        }

        rooted!(&in(cx) let target = window_proxy_target(proxy));
        return unsafe { JS_ForwardGetPropertyTo(cx, target.handle(), id, receiver, return_value) };
    }

    // Step 4. Return ? CrossOriginGet(this, P, Receiver).
    proxyhandler::cross_origin_get::<DomTypeHolder>(cx, proxy, receiver, id, return_value)
}

/// <https://html.spec.whatwg.org/multipage/#windowproxy-set>
#[expect(unsafe_code)]
unsafe extern "C" fn set(
    cx: *mut RawJSContext,
    proxy: RawHandleObject,
    id: RawHandleId,
    v: RawHandleValue,
    receiver: RawHandleValue,
    res: *mut ObjectOpResult,
) -> bool {
    let mut cx = unsafe {
        // SAFETY: We are in SM hook
        JSContext::from_ptr(NonNull::new(cx).expect("JSContext should not be null in SM hook"))
    };
    let mut cx = CurrentRealm::assert(&mut cx);
    let cx = &mut cx;

    // Step 1. Let W be the value of the [[Window]] internal slot of this.
    // Note: This is the `proxy` argument.

    // Step 2. Check if an access between two browsing contexts should be reported, given the
    // current global object's browsing context, W's browsing context, P, and the current settings
    // object.
    // TODO: Implement this.

    let proxy = unsafe { Handle::from_raw(proxy) };
    let id = unsafe { Handle::from_raw(id) };

    // Step 3. If IsPlatformObjectSameOrigin(W) is true:
    if is_platform_object_same_origin(cx, proxy) {
        // Step 3.1. If P is an array index property name, then return false.
        if get_array_index_from_id(id).is_some() {
            // Reject (which means throw if and only if strict) the set.
            unsafe { (*res).code_ = JSErrNum::JSMSG_READ_ONLY as usize };
            return true;
        }

        // Step 3.2. Return ? OrdinarySet(W, P, V, Receiver).
        rooted!(&in(cx) let target = window_proxy_target(proxy));
        return unsafe {
            JS_ForwardSetPropertyTo(
                cx.raw_cx(),
                target.handle().into(),
                id.into(),
                v,
                receiver,
                res,
            )
        };
    }

    // Step 4. Return ? CrossOriginSet(this, P, V, Receiver).
    let receiver = unsafe { HandleValue::from_raw(receiver) };
    unsafe { cross_origin_set::<DomTypeHolder>(cx, proxy, id, v, receiver, res) }
}

#[expect(unsafe_code)]
unsafe extern "C" fn get_prototype_if_ordinary(
    _: *mut RawJSContext,
    _: RawHandleObject,
    is_ordinary: *mut bool,
    _: RawMutableHandleObject,
) -> bool {
    // Window's [[GetPrototypeOf]] trap isn't the ordinary definition:
    //
    //   https://html.spec.whatwg.org/multipage/#windowproxy-getprototypeof
    //
    // We nonetheless can implement it with a static [[Prototype]], because
    // wrapper-class handlers (particularly, XOW in FilteringWrapper.cpp) supply
    // all non-ordinary behavior.
    //
    // But from a spec point of view, it's the exact same object in both cases --
    // only the observer's changed.  So this getPrototypeIfOrdinary trap on the
    // non-wrapper object *must* report non-ordinary, even if static [[Prototype]]
    // usually means ordinary.
    unsafe { *is_ordinary = false };
    true
}

/// <https://html.spec.whatwg.org/multipage/#windowproxy-getprototypeof>
#[expect(unsafe_code)]
unsafe extern "C" fn get_prototype(
    cx: *mut RawJSContext,
    proxy: RawHandleObject,
    result: RawMutableHandleObject,
) -> bool {
    let mut cx = unsafe { JSContext::from_ptr(ptr::NonNull::new(cx).unwrap()) };
    let mut realm = CurrentRealm::assert(&mut cx);
    let proxy = unsafe { Handle::from_raw(proxy) };
    let result = unsafe { MutableHandleObject::from_raw(result) };
    maybe_cross_origin_get_prototype::<DomTypeHolder>(
        &mut realm,
        proxy,
        GetProtoObject::<DomTypeHolder>,
        result,
    )
}

/// <https://html.spec.whatwg.org/multipage/#windowproxy-delete>
#[expect(unsafe_code)]
unsafe extern "C" fn delete(
    cx: *mut RawJSContext,
    proxy: RawHandleObject,
    id: RawHandleId,
    result: *mut ObjectOpResult,
) -> bool {
    let mut cx = unsafe { JSContext::from_ptr(ptr::NonNull::new(cx).unwrap()) };
    let mut cx = CurrentRealm::assert(&mut cx);
    let cx = &mut cx;
    let proxy = unsafe { Handle::from_raw(proxy) };
    let id = unsafe { Handle::from_raw(id) };

    // Step 1. Let W be the value of the [[Window]] internal slot of this.
    // Note: This is the `proxy` argument.

    // Step 2. If IsPlatformObjectSameOrigin(W) is true:
    if is_platform_object_same_origin(cx, proxy) {
        // Step 2.1 If P is an array index property name:
        if get_array_index_from_id(id).is_some() {
            // Step 2.1.1. Let desc be ! this.[[GetOwnProperty]](P).
            let window = unsafe { GetSubframeWindowProxy(cx, proxy.into(), id.into()) };
            let code = if window.is_none() {
                // Step 2.1.2. If desc is undefined, then return true.
                0 /* OkCode */
            } else {
                // Step 2.1.3. Return false.
                JSErrNum::JSMSG_CANT_DELETE_WINDOW_ELEMENT as usize
            };
            unsafe { (*result).code_ = code };
            return true;
        }
        // Step 2.2. Return ? OrdinaryDelete(W, P).
        rooted!(&in(cx) let target = window_proxy_target(proxy));
        return unsafe {
            JS_DeletePropertyById(cx.raw_cx(), target.handle().into(), id.into(), result)
        };
    }

    // Step 3. Throw a "SecurityError" DOMException.
    report_cross_origin_denial::<DomTypeHolder>(cx, id, "delete")
}

/// <https://html.spec.whatwg.org/multipage#windowproxy-ownpropertykeys>
#[expect(unsafe_code)]
unsafe extern "C" fn own_property_keys(
    cx: *mut RawJSContext,
    proxy: RawHandleObject,
    property_keys: RawMutableHandleIdVector,
) -> bool {
    let mut cx = unsafe { JSContext::from_ptr(ptr::NonNull::new(cx).unwrap()) };
    let mut cx = CurrentRealm::assert(&mut cx);
    let cx = &mut cx;
    let proxy = unsafe { Handle::from_raw(proxy) };

    // Step 1. Let W be the value of the [[Window]] internal slot of this.
    // Note: This is the `proxy` argument.

    // Step 2. Let maxProperties be W's associated Document's document-tree child navigables's
    // size.
    rooted!(&in(cx) let target = window_proxy_target(proxy));
    let (max_properties, cross_origin_properties) = if let Ok(window) =
        root_from_handleobject::<Window>(cx, target.handle())
    {
        (window.Length(), unsafe {
            WindowBinding::CROSS_ORIGIN_PROPERTIES.get()
        })
    } else if let Ok(window) = root_from_handleobject::<DissimilarOriginWindow>(cx, target.handle())
    {
        // TODO: DissimilarOriginWindow currently always returns 0 for the length, so
        // this has the effect of not exposing any indexable attributes.
        (window.Length(), unsafe {
            DissimilarOriginWindowBinding::CROSS_ORIGIN_PROPERTIES.get()
        })
    } else {
        unreachable!("WindowProxy should always be backed by some kind of window");
    };

    // Step 3. Let keys be the range 0 to maxProperties, exclusive.
    rooted!(&in(cx) let mut rooted_index_jsid: jsid);
    for index in 0..max_properties {
        unsafe { int_to_jsid(index as i32, rooted_index_jsid.handle_mut()) };
        unsafe { AppendToIdVector(property_keys, rooted_index_jsid.handle()) };
    }

    if is_platform_object_same_origin(cx, proxy) {
        // Step 4. If IsPlatformObjectSameOrigin(W) is true, then return the concatenation of keys and
        // OrdinaryOwnPropertyKeys(W).
        return unsafe {
            GetPropertyKeys(
                cx,
                target.handle(),
                JSITER_OWNONLY | JSITER_HIDDEN | JSITER_SYMBOLS,
                property_keys,
            )
        };
    }

    // Step 5. Return the concatenation of keys and ! CrossOriginOwnPropertyKeys(W).
    cross_origin_own_property_keys(cx, proxy, cross_origin_properties, property_keys)
}

/// <https://html.spec.whatwg.org/multipage/#document-tree-child-navigable-target-name-property-set>
///
/// > The document-tree child navigable target name property set of a Window object window is the
/// > return value of running these steps:
///
/// > Step 1. Let children be the document-tree child navigables of window's associated Document.
/// > Step 2. Let firstNamedChildren be an empty ordered set.
/// > Step 3. For each navigable of children:
/// > Step 3.1. Let name be navigable's target name.
/// > Step 3.2. If name is the empty string, then continue.
/// > Step 3.3. If firstNamedChildren contains a navigable whose target name is name, then continue.
/// > Step 3.4. Append navigable to firstNamedChildren.
/// > Step 4. Let names be an empty ordered set.
/// > Step 5. For each navigable of firstNamedChildren:
/// > Step 5.1. Let name be navigable's target name.
/// > Step 5.2. If navigable's active document's origin is same origin with window's relevant settings
/// > object's origin, then append name to names.
/// > Step 6. Return names.
///
/// We don't implement these steps exactly, but we effectively do them using iterators below.
fn named_child_navigable(
    cx: &mut CurrentRealm,
    proxy: HandleObject,
    id: HandleId,
) -> Option<DomRoot<WindowProxy>> {
    let name = jsid_to_string(cx, id)?;
    if name.is_empty() {
        return None;
    }
    rooted!(&in(cx) let target = window_proxy_target(proxy));
    let window = root_from_handleobject::<Window>(cx, target.handle()).ok()?;
    window
        .Document()
        .iframes()
        .iter()
        .filter_map(|iframe| iframe.GetContentWindow())
        .find(|window_proxy| window_proxy.get_name() == name)
}

static PROXY_TRAPS: ProxyTraps = ProxyTraps {
    enter: None,
    getOwnPropertyDescriptor: Some(get_own_property_descriptor),
    defineProperty: Some(define_property),
    ownPropertyKeys: Some(own_property_keys),
    delete_: Some(delete),
    enumerate: None,
    getPrototypeIfOrdinary: Some(get_prototype_if_ordinary),
    getPrototype: Some(get_prototype),
    setPrototype: Some(maybe_cross_origin_set_prototype_rawcx),
    setImmutablePrototype: None,
    preventExtensions: Some(prevent_extensions),
    isExtensible: Some(is_extensible),
    has: Some(has),
    get: Some(get),
    set: Some(set),
    call: None,
    construct: None,
    hasOwn: Some(has_own),
    getOwnEnumerablePropertyKeys: None,
    nativeCall: None,
    objectClassIs: None,
    className: None,
    fun_toString: None,
    boxedValue_unbox: None,
    defaultValue: None,
    trace: Some(trace),
    finalize: Some(finalize),
    objectMoved: None,
    isCallable: None,
    isConstructor: None,
};

/// Proxy handler for a WindowProxy.
/// Has ownership of the inner pointer and deallocates it when it is no longer needed.
pub(crate) struct WindowProxyHandler(*const libc::c_void);

impl MallocSizeOf for WindowProxyHandler {
    fn size_of(&self, _ops: &mut MallocSizeOfOps) -> usize {
        // FIXME(#6907) this is a pointer to memory allocated by `new` in NewProxyHandler in rust-mozjs.
        0
    }
}

// Safety: Send and Sync is guaranteed since the underlying pointer and all its associated methods in C++ are const.
#[expect(unsafe_code)]
unsafe impl Send for WindowProxyHandler {}
// Safety: Send and Sync is guaranteed since the underlying pointer and all its associated methods in C++ are const.
#[expect(unsafe_code)]
unsafe impl Sync for WindowProxyHandler {}

#[expect(unsafe_code)]
impl WindowProxyHandler {
    fn new(traps: &ProxyTraps) -> Self {
        // Safety: Foreign function generated by bindgen. Pointer is freed in drop to prevent memory leak.
        let ptr = unsafe { CreateWrapperProxyHandler(traps) };
        assert!(!ptr.is_null());
        Self(ptr)
    }

    /// Returns a single, shared WindowProxyHandler that contains normal PROXY_TRAPS.
    pub(crate) fn proxy_handler() -> &'static Self {
        use std::sync::OnceLock;
        /// We are sharing a single instance for the entire programs here due to lifetime issues.
        /// The pointer in self.0 is known to C++ and visited by the GC. Hence, we don't know when
        /// it is safe to free it.
        /// Sharing a single instance should be fine because all methods on this pointer in C++
        /// are const and don't modify its internal state.
        static SINGLETON: OnceLock<WindowProxyHandler> = OnceLock::new();
        SINGLETON.get_or_init(|| Self::new(&PROXY_TRAPS))
    }

    /// Creates a new WindowProxy object on the C++ side and returns the pointer to it.
    /// The pointer should be owned by the GC.
    fn new_window_proxy(
        &self,
        cx: &mut JSContext,
        window_jsobject: js::gc::HandleObject,
    ) -> *mut JSObject {
        let obj = unsafe { NewWindowProxy(cx, window_jsobject, self.0) };
        assert!(!obj.is_null());
        obj
    }
}

#[expect(unsafe_code)]
impl Drop for WindowProxyHandler {
    fn drop(&mut self) {
        // Safety: Pointer is allocated by corresponding C++ function, owned by this
        // struct and not accessible from outside.
        unsafe {
            DeleteWrapperProxyHandler(self.0);
        }
    }
}

// How WindowProxy objects are garbage collected.

#[expect(unsafe_code)]
unsafe extern "C" fn finalize(_fop: *mut GCContext, obj: *mut JSObject) {
    let mut slot = UndefinedValue();
    unsafe { GetProxyReservedSlot(obj, 0, &mut slot) };
    let this = slot.to_private() as *mut WindowProxy;
    if this.is_null() {
        // GC during obj creation or after transplanting.
        return;
    }
    unsafe {
        (*this).reflector.drop_memory(&*this);
        let jsobject = (*this).reflector.get_jsobject().get();
        debug!(
            "WindowProxy finalize: {:p}, with reflector {:p} from {:p}.",
            this, jsobject, obj
        );
        let _ = Box::from_raw(this);
    }
}

#[expect(unsafe_code)]
unsafe extern "C" fn trace(trc: *mut JSTracer, obj: *mut JSObject) {
    let mut slot = UndefinedValue();
    unsafe { GetProxyReservedSlot(obj, 0, &mut slot) };
    let this = slot.to_private() as *const WindowProxy;
    if this.is_null() {
        // GC during obj creation or after transplanting.
        return;
    }
    unsafe { (*this).trace(trc) };
}