Add new Window globals as debuggees

Signed-off-by: Delan Azabani <dazabani@igalia.com>
Co-authored-by: atbrakhi <atbrakhi@igalia.com>

components/script/dom/debuggerevent.rs

@@ -0,0 +1,64 @@
+/* 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::default::Default;
+use std::ptr::NonNull;
+
+use dom_struct::dom_struct;
+use js::jsapi::{JSObject, Value};
+use script_bindings::conversions::SafeToJSValConvertible;
+use script_bindings::reflector::DomObject;
+
+use crate::dom::bindings::codegen::Bindings::DebuggerEventBinding::DebuggerEventMethods;
+use crate::dom::bindings::codegen::Bindings::EventBinding::Event_Binding::EventMethods;
+use crate::dom::bindings::reflector::reflect_dom_object;
+use crate::dom::bindings::root::{DomRoot, MutNullableDom};
+use crate::dom::event::Event;
+use crate::dom::types::GlobalScope;
+use crate::script_runtime::CanGc;
+
+#[dom_struct]
+/// Event for Rust → JS calls in [`crate::dom::DebuggerGlobalScope`].
+pub(crate) struct DebuggerEvent {
+    event: Event,
+    global: MutNullableDom<GlobalScope>,
+}
+
+impl DebuggerEvent {
+    pub(crate) fn new(
+        debugger_global: &GlobalScope,
+        global: &GlobalScope,
+        can_gc: CanGc,
+    ) -> DomRoot<Self> {
+        let result = Box::new(Self {
+            event: Event::new_inherited(),
+            global: Default::default(),
+        });
+        // TODO: make these fields not optional somehow?
+        result.global.set(Some(global));
+
+        result.event.init_event("addDebuggee".into(), false, false);
+
+        reflect_dom_object(result, debugger_global, can_gc)
+    }
+}
+
+impl DebuggerEventMethods<crate::DomTypeHolder> for DebuggerEvent {
+    // check-tidy: no specs after this line
+    fn Global(&self, r#cx: script_bindings::script_runtime::JSContext) -> NonNull<JSObject> {
+        // Convert the debuggee global’s reflector to a Value, wrapping it from its originating realm (debuggee realm)
+        // into the active realm (debugger realm) so that it can be passed across compartments.
+        rooted!(in(*cx) let mut result: Value);
+        self.global
+            .get()
+            .expect("Guaranteed by new")
+            .reflector()
+            .safe_to_jsval(cx, result.handle_mut());
+        NonNull::new(result.to_object()).unwrap()
+    }
+
+    fn IsTrusted(&self) -> bool {
+        self.event.IsTrusted()
+    }
+}

components/script/dom/debuggerglobalscope.rs

@@ -24,7 +24,9 @@ use crate::dom::bindings::inheritance::Castable;
 use crate::dom::bindings::root::DomRoot;
 use crate::dom::bindings::trace::CustomTraceable;
 use crate::dom::bindings::utils::define_all_exposed_interfaces;
+use crate::dom::event::EventStatus;
 use crate::dom::globalscope::GlobalScope;
+use crate::dom::types::{DebuggerEvent, Event};
 #[cfg(feature = "testbinding")]
 #[cfg(feature = "webgpu")]
 use crate::dom::webgpu::identityhub::IdentityHub;
@@ -119,4 +121,14 @@ impl DebuggerGlobalScope {
             report_pending_exception(Self::get_cx(), true, InRealm::Entered(&ar), can_gc);
         }
     }
+
+    #[allow(unsafe_code)]
+    pub(crate) fn fire_add_debuggee(&self, can_gc: CanGc, global: &GlobalScope) {
+        let event = DomRoot::upcast::<Event>(DebuggerEvent::new(self.upcast(), global, can_gc));
+        assert_eq!(
+            event.fire(self.upcast(), can_gc),
+            EventStatus::NotCanceled,
+            "Guaranteed by DebuggerEvent::new"
+        );
+    }
 }

components/script/dom/event.rs

@@ -1105,7 +1105,7 @@ pub(crate) enum EventDefault {
     Handled,
 }
 
-#[derive(PartialEq)]
+#[derive(Debug, PartialEq)]
 pub(crate) enum EventStatus {
     Canceled,
     NotCanceled,

components/script/dom/mod.rs

@@ -289,6 +289,7 @@ pub(crate) mod customevent;
 pub(crate) mod datatransfer;
 pub(crate) mod datatransferitem;
 pub(crate) mod datatransferitemlist;
+pub(crate) mod debuggerevent;
 pub(crate) mod debuggerglobalscope;
 pub(crate) mod dedicatedworkerglobalscope;
 pub(crate) mod defaultteereadrequest;

components/script/script_thread.rs

@@ -3449,6 +3449,8 @@ impl ScriptThread {
             incomplete.load_data.inherited_secure_context,
             incomplete.theme,
         );
+        self.debugger_global
+            .fire_add_debuggee(can_gc, window.upcast());
 
         let _realm = enter_realm(&*window);
 

components/script_bindings/webidls/DebuggerEvent.webidl

@@ -0,0 +1,10 @@
+/* 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/. */
+
+// This interface is entirely internal to Servo, and should not be accessible to
+// web pages.
+[Exposed=DebuggerGlobalScope]
+interface DebuggerEvent : Event {
+    readonly attribute object global;
+};

resources/debugger.js

@@ -1,3 +1,20 @@
 if (!("dbg" in this)) {
     dbg = new Debugger;
+
+    dbg.onNewGlobalObject = function(global) {
+        console.log("[debugger] onNewGlobalObject");
+        console.log(this, global);
+    };
+
+    dbg.onNewScript = function(script, global) {
+        console.log("[debugger] onNewScript");
+        console.log(this, script, global);
+    };
 }
+
+addEventListener("addDebuggee", event => {
+    const {global} = event;
+    console.log("[debugger] Adding debuggee");
+    dbg.addDebuggee(global);
+    console.log("[debugger] getDebuggees().length =", dbg.getDebuggees().length);
+});