script: add initialize_ui_event method (#34524)

* retire UIEvent::InitUIEvent

Signed-off-by: Jay Wang <xdddxyyyxzzz123@gmail.com>

* fix fmt

Signed-off-by: Jay Wang <xdddxyyyxzzz123@gmail.com>

* remove unused changes

Signed-off-by: Jay Wang <xdddxyyyxzzz123@gmail.com>

* reimplement the spec and reuse wherever we can

Signed-off-by: Jay Wang <xdddxyyyxzzz123@gmail.com>

* fix lint

Signed-off-by: Jay Wang <xdddxyyyxzzz123@gmail.com>

---------

Signed-off-by: Jay Wang <xdddxyyyxzzz123@gmail.com>

components/script/dom/event.rs

@@ -126,6 +126,10 @@ impl Event {
         self.cancelable.set(cancelable);
     }
 
+    pub fn set_target(&self, target_: Option<&EventTarget>) {
+        self.target.set(target_);
+    }
+
     /// <https://dom.spec.whatwg.org/#event-path>
     // TODO: shadow roots put special flags in the path,
     // and it will stop just being a list of bare EventTargets

components/script/dom/uievent.rs

@@ -9,15 +9,19 @@ use dom_struct::dom_struct;
 use js::rust::HandleObject;
 use servo_atoms::Atom;
 
+use super::node::document_from_node;
 use crate::dom::bindings::codegen::Bindings::EventBinding::EventMethods;
 use crate::dom::bindings::codegen::Bindings::UIEventBinding;
 use crate::dom::bindings::codegen::Bindings::UIEventBinding::UIEventMethods;
+use crate::dom::bindings::codegen::Bindings::WindowBinding::Window_Binding::WindowMethods;
 use crate::dom::bindings::error::Fallible;
 use crate::dom::bindings::inheritance::Castable;
 use crate::dom::bindings::reflector::reflect_dom_object_with_proto;
 use crate::dom::bindings::root::{DomRoot, MutNullableDom};
 use crate::dom::bindings::str::DOMString;
+use crate::dom::element::Element;
 use crate::dom::event::{Event, EventBubbles, EventCancelable};
+use crate::dom::eventtarget::EventTarget;
 use crate::dom::window::Window;
 use crate::script_runtime::CanGc;
 
@@ -76,15 +80,39 @@ impl UIEvent {
         can_gc: CanGc,
     ) -> DomRoot<UIEvent> {
         let ev = UIEvent::new_uninitialized_with_proto(window, proto, can_gc);
-        ev.InitUIEvent(
+        ev.initialize_ui_event(
             type_,
-            bool::from(can_bubble),
+            view.map(|window| window.upcast::<EventTarget>()),
-            bool::from(cancelable),
+            can_bubble,
-            view,
+            cancelable,
-            detail,
         );
+        ev.detail.set(detail);
         ev
     }
+
+    /// <https://w3c.github.io/uievents/#initialize-a-uievent>
+    pub fn initialize_ui_event(
+        &self,
+        type_: DOMString,
+        target_: Option<&EventTarget>,
+        bubbles: EventBubbles,
+        cancelable: EventCancelable,
+    ) {
+        // 1. Initialize the base Event attributes:
+        self.event
+            .init_event(type_.into(), bool::from(bubbles), bool::from(cancelable));
+        self.event.set_target(target_);
+        // 2. Initialize view/detail:
+        if let Some(target_) = target_ {
+            let element = target_.downcast::<Element>();
+            let document = match element {
+                Some(element) => document_from_node(element),
+                None => target_.downcast::<Window>().unwrap().Document(),
+            };
+            self.view.set(Some(document.window()));
+        }
+        self.detail.set(0_i32);
+    }
 }
 
 impl UIEventMethods<crate::DomTypeHolder> for UIEvent {