script: implement AbortController (#31361)

* Implement AbortController

Signed-off-by: syvb <me@iter.ca>

* Update WPT tests

Signed-off-by: syvb <me@iter.ca>

* Address review comments

* Fix duplicate import generation

* Update WPT test expectations

* Change expectation to FAIL for flaky test

---------

Signed-off-by: syvb <me@iter.ca>

1 files changed, 139 insertions, 0 deletions

diff --git a/components/script/dom/abortsignal.rs b/components/script/dom/abortsignal.rs
new file mode 100644
index 00000000000..75a7568559c
--- /dev/null
+++ b/components/script/dom/abortsignal.rs
@@ -0,0 +1,139 @@
+/* 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::rc::Rc;
+
+use dom_struct::dom_struct;
+use js::conversions::ToJSValConvertible;
+use js::jsapi::{ExceptionStackBehavior, Heap, JS_IsExceptionPending};
+use js::jsval::{JSVal, UndefinedValue};
+use js::rust::wrappers::JS_SetPendingException;
+use js::rust::HandleValue;
+
+use crate::dom::bindings::cell::DomRefCell;
+use crate::dom::bindings::codegen::Bindings::AbortSignalBinding::AbortSignalMethods;
+use crate::dom::bindings::codegen::Bindings::EventListenerBinding::EventListener;
+use crate::dom::bindings::codegen::Bindings::EventTargetBinding::EventListenerOptions;
+use crate::dom::bindings::inheritance::Castable;
+use crate::dom::bindings::reflector::{reflect_dom_object, DomObject};
+use crate::dom::bindings::root::DomRoot;
+use crate::dom::bindings::str::DOMString;
+use crate::dom::domexception::DOMErrorName;
+use crate::dom::event::{Event, EventBubbles, EventCancelable};
+use crate::dom::eventtarget::EventTarget;
+use crate::dom::globalscope::GlobalScope;
+use crate::dom::types::DOMException;
+use crate::script_runtime::JSContext;
+
+#[derive(JSTraceable, MallocSizeOf)]
+pub enum AbortAlgorithm {
+    RemoveEventListener(
+        DomRoot<EventTarget>,
+        DOMString,
+        #[ignore_malloc_size_of = "Rc"] Rc<EventListener>,
+        #[ignore_malloc_size_of = "generated"] EventListenerOptions,
+    ),
+}
+impl AbortAlgorithm {
+    fn exec(self) {
+        match self {
+            Self::RemoveEventListener(target, ty, listener, options) => {
+                target.remove_event_listener(ty, Some(listener), options)
+            },
+        }
+    }
+}
+
+#[dom_struct]
+pub struct AbortSignal {
+    event_target: EventTarget,
+    #[ignore_malloc_size_of = "Defined in rust-mozjs"]
+    reason: Heap<JSVal>,
+    abort_algorithms: DomRefCell<Vec<AbortAlgorithm>>,
+}
+
+impl AbortSignal {
+    pub fn new_inherited() -> Self {
+        Self {
+            event_target: EventTarget::new_inherited(),
+            reason: Heap::default(),
+            abort_algorithms: DomRefCell::default(),
+        }
+    }
+    pub fn new(global: &GlobalScope) -> DomRoot<Self> {
+        reflect_dom_object(Box::new(Self::new_inherited()), global)
+    }
+    /// <https://dom.spec.whatwg.org/#abortsignal-add>
+    pub fn add_abort_algorithm(&self, alg: AbortAlgorithm) {
+        if !self.Aborted() {
+            self.abort_algorithms.borrow_mut().push(alg);
+        }
+    }
+    /// <https://dom.spec.whatwg.org/#abortsignal-signal-abort>
+    #[allow(unsafe_code)]
+    pub fn signal_abort(&self, reason: HandleValue) {
+        // 1. If signal is aborted, then return.
+        if self.Aborted() {
+            return;
+        }
+        // 2. Set signal’s abort reason to reason if it is given; otherwise to a new "AbortError" DOMException.
+        let cx = *GlobalScope::get_cx();
+        rooted!(in(cx) let mut new_reason = UndefinedValue());
+        let reason = if reason.is_undefined() {
+            let exception = DOMException::new(&self.global(), DOMErrorName::AbortError);
+            unsafe {
+                exception.to_jsval(cx, new_reason.handle_mut());
+            };
+            new_reason.handle()
+        } else {
+            reason
+        };
+        self.reason.set(reason.get());
+
+        // 3. For each algorithm of signal’s abort algorithms: run algorithm.
+        // 4. Empty signal’s abort algorithms.
+        for algorithm in self.abort_algorithms.borrow_mut().drain(..) {
+            algorithm.exec();
+        }
+
+        // 5. Fire an event named abort at signal.
+        let event = Event::new(
+            &self.global(),
+            atom!("abort"),
+            EventBubbles::DoesNotBubble,
+            EventCancelable::Cancelable,
+        );
+        event.fire(self.upcast());
+        // 6. For each dependentSignal of signal’s dependent signals,
+        // signal abort on dependentSignal with signal’s abort reason.
+        // TODO
+    }
+}
+
+impl AbortSignalMethods for AbortSignal {
+    // https://dom.spec.whatwg.org/#dom-abortsignal-onabort
+    event_handler!(Abort, GetOnabort, SetOnabort);
+    /// <https://dom.spec.whatwg.org/#dom-abortsignal-aborted>
+    fn Aborted(&self) -> bool {
+        !self.reason.get().is_undefined()
+    }
+    /// <https://dom.spec.whatwg.org/#dom-abortsignal-reason>
+    fn Reason(&self, _cx: JSContext) -> JSVal {
+        self.reason.get()
+    }
+    #[allow(unsafe_code)]
+    /// <https://dom.spec.whatwg.org/#dom-abortsignal-throwifaborted>
+    fn ThrowIfAborted(&self) {
+        let reason = self.reason.get();
+        if !reason.is_undefined() {
+            let cx = *GlobalScope::get_cx();
+            unsafe {
+                assert!(!JS_IsExceptionPending(cx));
+                rooted!(in(cx) let mut thrown = UndefinedValue());
+                reason.to_jsval(cx, thrown.handle_mut());
+                JS_SetPendingException(cx, thrown.handle(), ExceptionStackBehavior::Capture);
+            }
+        }
+    }
+}