Bug 1737771 - Implement AbortSignal.reason r=mgaudet,smaug

Differential Revision: https://phabricator.services.mozilla.com/D132281

dom/abort/AbortController.cpp

@@ -6,12 +6,27 @@
 
 #include "AbortController.h"
 #include "AbortSignal.h"
+#include "js/Value.h"
 #include "mozilla/dom/AbortControllerBinding.h"
+#include "mozilla/dom/DOMException.h"
 #include "mozilla/dom/WorkerPrivate.h"
 
 namespace mozilla::dom {
 
-NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE(AbortController, mGlobal, mSignal)
+NS_IMPL_CYCLE_COLLECTION_CLASS(AbortController)
+NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(AbortController)
+  NS_IMPL_CYCLE_COLLECTION_UNLINK(mGlobal, mSignal)
+  tmp->mReason.setUndefined();
+  NS_IMPL_CYCLE_COLLECTION_UNLINK_PRESERVED_WRAPPER
+NS_IMPL_CYCLE_COLLECTION_UNLINK_END
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(AbortController)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mGlobal, mSignal)
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
+
+NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN(AbortController)
+  NS_IMPL_CYCLE_COLLECTION_TRACE_PRESERVED_WRAPPER
+  NS_IMPL_CYCLE_COLLECTION_TRACE_JS_MEMBER_CALLBACK(mReason)
+NS_IMPL_CYCLE_COLLECTION_TRACE_END
 
 NS_IMPL_CYCLE_COLLECTING_ADDREF(AbortController)
 NS_IMPL_CYCLE_COLLECTING_RELEASE(AbortController)
@@ -35,7 +50,9 @@ already_AddRefed<AbortController> AbortController::Constructor(
 }
 
 AbortController::AbortController(nsIGlobalObject* aGlobal)
-    : mGlobal(aGlobal), mAborted(false) {}
+    : mGlobal(aGlobal), mAborted(false), mReason(JS::UndefinedHandleValue) {
+  mozilla::HoldJSObjects(this);
+}
 
 JSObject* AbortController::WrapObject(JSContext* aCx,
                                       JS::Handle<JSObject*> aGivenProto) {
@@ -46,13 +63,14 @@ nsIGlobalObject* AbortController::GetParentObject() const { return mGlobal; }
 
 AbortSignal* AbortController::Signal() {
   if (!mSignal) {
-    mSignal = new AbortSignal(mGlobal, mAborted);
+    JS::Rooted<JS::Value> reason(RootingCx(), mReason);
+    mSignal = new AbortSignal(mGlobal, mAborted, reason);
   }
 
   return mSignal;
 }
 
-void AbortController::Abort() {
+void AbortController::Abort(JSContext* aCx, JS::Handle<JS::Value> aReason) {
   if (mAborted) {
     return;
   }
@@ -60,8 +78,12 @@ void AbortController::Abort() {
   mAborted = true;
 
   if (mSignal) {
-    mSignal->SignalAbort();
+    mSignal->SignalAbort(aReason);
+  } else {
+    mReason = aReason;
   }
 }
 
+AbortController::~AbortController() { mozilla::DropJSObjects(this); }
+
 }  // namespace mozilla::dom

dom/abort/AbortController.h

@@ -38,15 +38,16 @@ class AbortController final : public nsISupports, public nsWrapperCache {
 
   AbortSignal* Signal();
 
-  void Abort();
+  void Abort(JSContext* aCx, JS::Handle<JS::Value> aReason);
 
  private:
-  ~AbortController() = default;
+  ~AbortController();
 
   nsCOMPtr<nsIGlobalObject> mGlobal;
   RefPtr<AbortSignal> mSignal;
 
   bool mAborted;
+  JS::Heap<JS::Value> mReason;
 };
 
 }  // namespace dom

dom/abort/AbortFollower.h

@@ -7,6 +7,7 @@
 #ifndef mozilla_dom_AbortFollower_h
 #define mozilla_dom_AbortFollower_h
 
+#include "jsapi.h"
 #include "nsISupportsImpl.h"
 #include "nsTObserverArray.h"
 
@@ -47,11 +48,16 @@ class AbortFollower : public nsISupports {
 
 class AbortSignalImpl : public nsISupports {
  public:
-  explicit AbortSignalImpl(bool aAborted);
+  explicit AbortSignalImpl(bool aAborted, JS::Handle<JS::Value> aReason);
 
   bool Aborted() const;
 
-  virtual void SignalAbort();
+  // Web IDL Layer
+  void GetReason(JSContext* aCx, JS::MutableHandle<JS::Value> aReason);
+  // Helper for other DOM code
+  JS::Value RawReason() const;
+
+  virtual void SignalAbort(JS::Handle<JS::Value> aReason);
 
  protected:
   // Subclasses of this class must call these Traverse and Unlink functions
@@ -59,15 +65,17 @@ class AbortSignalImpl : public nsISupports {
   static void Traverse(AbortSignalImpl* aSignal,
                        nsCycleCollectionTraversalCallback& cb);
 
-  static void Unlink(AbortSignalImpl* aSignal) {
-    // To be filled in shortly.
-  }
+  static void Unlink(AbortSignalImpl* aSignal);
 
   virtual ~AbortSignalImpl() = default;
 
+  JS::Heap<JS::Value> mReason;
+
  private:
   friend class AbortFollower;
 
+  void MaybeAssignAbortError(JSContext* aCx);
+
   // Raw pointers.  |AbortFollower::Follow| adds to this array, and
   // |AbortFollower::Unfollow| (also callbed by the destructor) will remove
   // from this array.  Finally, calling |SignalAbort()| will (after running all

dom/abort/AbortSignal.cpp

@@ -6,22 +6,39 @@
 
 #include "AbortSignal.h"
 
+#include "mozilla/dom/DOMException.h"
 #include "mozilla/dom/Event.h"
 #include "mozilla/dom/EventBinding.h"
 #include "mozilla/dom/AbortSignalBinding.h"
+#include "mozilla/dom/ToJSValue.h"
 #include "mozilla/RefPtr.h"
+#include "nsCycleCollectionParticipant.h"
 
 namespace mozilla::dom {
 
 // AbortSignalImpl
 // ----------------------------------------------------------------------------
 
-AbortSignalImpl::AbortSignalImpl(bool aAborted) : mAborted(aAborted) {}
+AbortSignalImpl::AbortSignalImpl(bool aAborted, JS::Handle<JS::Value> aReason)
+    : mReason(aReason), mAborted(aAborted) {
+  MOZ_ASSERT_IF(!mReason.isUndefined(), mAborted);
+}
 
 bool AbortSignalImpl::Aborted() const { return mAborted; }
 
+void AbortSignalImpl::GetReason(JSContext* aCx,
+                                JS::MutableHandle<JS::Value> aReason) {
+  if (!mAborted) {
+    return;
+  }
+  MaybeAssignAbortError(aCx);
+  aReason.set(mReason);
+}
+
+JS::Value AbortSignalImpl::RawReason() const { return mReason.get(); }
+
 // https://dom.spec.whatwg.org/#abortsignal-signal-abort steps 1-4
-void AbortSignalImpl::SignalAbort() {
+void AbortSignalImpl::SignalAbort(JS::Handle<JS::Value> aReason) {
   // Step 1.
   if (mAborted) {
     return;
@@ -29,6 +46,7 @@ void AbortSignalImpl::SignalAbort() {
 
   // Step 2.
   mAborted = true;
+  mReason = aReason;
 
   // Step 3.
   // When there are multiple followers, the follower removal algorithm
@@ -48,11 +66,31 @@ void AbortSignalImpl::SignalAbort() {
   mFollowers.Clear();
 }
 
-/* static */ void AbortSignalImpl::Traverse(
-    AbortSignalImpl* aSignal, nsCycleCollectionTraversalCallback& cb) {
+void AbortSignalImpl::Traverse(AbortSignalImpl* aSignal,
+                               nsCycleCollectionTraversalCallback& cb) {
   // To be filled in shortly.
 }
 
+void AbortSignalImpl::Unlink(AbortSignalImpl* aSignal) {
+  aSignal->mReason.setUndefined();
+}
+
+void AbortSignalImpl::MaybeAssignAbortError(JSContext* aCx) {
+  MOZ_ASSERT(mAborted);
+  if (!mReason.isUndefined()) {
+    return;
+  }
+
+  JS::Rooted<JS::Value> exception(aCx);
+  RefPtr<DOMException> dom = DOMException::Create(NS_ERROR_DOM_ABORT_ERR);
+
+  if (NS_WARN_IF(!ToJSValue(aCx, dom, &exception))) {
+    return;
+  }
+
+  mReason.set(exception);
+}
+
 // AbortSignal
 // ----------------------------------------------------------------------------
 
@@ -73,27 +111,38 @@ NS_IMPL_CYCLE_COLLECTION_UNLINK_END
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(AbortSignal)
 NS_INTERFACE_MAP_END_INHERITING(DOMEventTargetHelper)
 
+NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN_INHERITED(AbortSignal,
+                                               DOMEventTargetHelper)
+  NS_IMPL_CYCLE_COLLECTION_TRACE_JS_MEMBER_CALLBACK(mReason)
+NS_IMPL_CYCLE_COLLECTION_TRACE_END
+
 NS_IMPL_ADDREF_INHERITED(AbortSignal, DOMEventTargetHelper)
 NS_IMPL_RELEASE_INHERITED(AbortSignal, DOMEventTargetHelper)
 
-AbortSignal::AbortSignal(nsIGlobalObject* aGlobalObject, bool aAborted)
-    : DOMEventTargetHelper(aGlobalObject), AbortSignalImpl(aAborted) {}
+AbortSignal::AbortSignal(nsIGlobalObject* aGlobalObject, bool aAborted,
+                         JS::Handle<JS::Value> aReason)
+    : DOMEventTargetHelper(aGlobalObject), AbortSignalImpl(aAborted, aReason) {
+  mozilla::HoldJSObjects(this);
+}
 
 JSObject* AbortSignal::WrapObject(JSContext* aCx,
                                   JS::Handle<JSObject*> aGivenProto) {
   return AbortSignal_Binding::Wrap(aCx, this, aGivenProto);
 }
 
-already_AddRefed<AbortSignal> AbortSignal::Abort(GlobalObject& aGlobal) {
+already_AddRefed<AbortSignal> AbortSignal::Abort(GlobalObject& aGlobal,
+                                                 JS::Handle<JS::Value> aReason,
+                                                 ErrorResult& aRv) {
   nsCOMPtr<nsIGlobalObject> global = do_QueryInterface(aGlobal.GetAsSupports());
-  RefPtr<AbortSignal> abortSignal = new AbortSignal(global, true);
+
+  RefPtr<AbortSignal> abortSignal = new AbortSignal(global, true, aReason);
   return abortSignal.forget();
 }
 
 // https://dom.spec.whatwg.org/#abortsignal-signal-abort
-void AbortSignal::SignalAbort() {
+void AbortSignal::SignalAbort(JS::Handle<JS::Value> aReason) {
   // Steps 1-4.
-  AbortSignalImpl::SignalAbort();
+  AbortSignalImpl::SignalAbort(aReason);
 
   // Step 5.
   EventInit init;
@@ -106,6 +155,13 @@ void AbortSignal::SignalAbort() {
   DispatchEvent(*event);
 }
 
+void AbortSignal::RunAbortAlgorithm() {
+  JS::Rooted<JS::Value> reason(RootingCx(), Signal()->RawReason());
+  SignalAbort(reason);
+}
+
+AbortSignal::~AbortSignal() { mozilla::DropJSObjects(this); }
+
 // AbortFollower
 // ----------------------------------------------------------------------------
 

dom/abort/AbortSignal.h

@@ -30,25 +30,29 @@ class AbortSignal final : public DOMEventTargetHelper,
                           public AbortFollower {
  public:
   NS_DECL_ISUPPORTS_INHERITED
-  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(AbortSignal, DOMEventTargetHelper)
+  NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS_INHERITED(AbortSignal,
+                                                         DOMEventTargetHelper)
 
-  AbortSignal(nsIGlobalObject* aGlobalObject, bool aAborted);
+  AbortSignal(nsIGlobalObject* aGlobalObject, bool aAborted,
+              JS::Handle<JS::Value> aReason);
 
   JSObject* WrapObject(JSContext* aCx,
                        JS::Handle<JSObject*> aGivenProto) override;
 
   IMPL_EVENT_HANDLER(abort);
 
-  static already_AddRefed<AbortSignal> Abort(GlobalObject& aGlobal);
+  static already_AddRefed<AbortSignal> Abort(GlobalObject& aGlobal,
+                                             JS::Handle<JS::Value> aReason,
+                                             ErrorResult& aRv);
 
   // AbortSignalImpl
-  void SignalAbort() override;
+  void SignalAbort(JS::Handle<JS::Value> aReason) override;
 
   // AbortFollower
-  void RunAbortAlgorithm() override { SignalAbort(); }
+  void RunAbortAlgorithm() override;
 
  private:
-  ~AbortSignal() = default;
+  ~AbortSignal();
 };
 
 }  // namespace dom

dom/fetch/Fetch.cpp

@@ -6,6 +6,7 @@
 
 #include "Fetch.h"
 
+#include "js/Value.h"
 #include "mozilla/dom/Document.h"
 #include "mozilla/ipc/PBackgroundSharedTypes.h"
 #include "nsIGlobalObject.h"
@@ -81,12 +82,15 @@ void AbortStream(JSContext* aCx, JS::Handle<JSObject*> aStream,
 class AbortSignalMainThread final : public AbortSignalImpl {
  public:
   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
-  NS_DECL_CYCLE_COLLECTION_CLASS(AbortSignalMainThread)
+  NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(AbortSignalMainThread)
 
-  explicit AbortSignalMainThread(bool aAborted) : AbortSignalImpl(aAborted) {}
+  explicit AbortSignalMainThread(bool aAborted)
+      : AbortSignalImpl(aAborted, JS::UndefinedHandleValue) {
+    mozilla::HoldJSObjects(this);
+  }
 
  private:
-  ~AbortSignalMainThread() = default;
+  ~AbortSignalMainThread() { mozilla::DropJSObjects(this); };
 };
 
 NS_IMPL_CYCLE_COLLECTION_CLASS(AbortSignalMainThread)
@@ -99,6 +103,10 @@ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(AbortSignalMainThread)
   AbortSignalImpl::Traverse(static_cast<AbortSignalImpl*>(tmp), cb);
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
 
+NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN(AbortSignalMainThread)
+  NS_IMPL_CYCLE_COLLECTION_TRACE_JS_MEMBER_CALLBACK(mReason)
+NS_IMPL_CYCLE_COLLECTION_TRACE_END
+
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(AbortSignalMainThread)
   NS_INTERFACE_MAP_ENTRY(nsISupports)
 NS_INTERFACE_MAP_END
@@ -212,7 +220,7 @@ NS_IMPL_ISUPPORTS0(AbortSignalProxy)
 NS_IMETHODIMP WorkerSignalFollower::AbortSignalProxyRunnable::Run() {
   MOZ_ASSERT(NS_IsMainThread());
   AbortSignalImpl* signalImpl = mProxy->GetOrCreateSignalImplForMainThread();
-  signalImpl->SignalAbort();
+  signalImpl->SignalAbort(JS::UndefinedHandleValue);
   return NS_OK;
 }
 

dom/fetch/Request.cpp

@@ -6,6 +6,7 @@
 
 #include "Request.h"
 
+#include "js/Value.h"
 #include "nsIURI.h"
 #include "nsNetUtil.h"
 #include "nsPIDOMWindow.h"
@@ -63,7 +64,8 @@ Request::Request(nsIGlobalObject* aOwner, SafeRefPtr<InternalRequest> aRequest,
   if (aSignal) {
     // If we don't have a signal as argument, we will create it when required by
     // content, otherwise the Request's signal must follow what has been passed.
-    mSignal = new AbortSignal(aOwner, aSignal->Aborted());
+    JS::Rooted<JS::Value> reason(RootingCx(), aSignal->RawReason());
+    mSignal = new AbortSignal(aOwner, aSignal->Aborted(), reason);
     if (!mSignal->Aborted()) {
       mSignal->Follow(aSignal);
     }
@@ -651,7 +653,7 @@ Headers* Request::Headers_() {
 
 AbortSignal* Request::GetOrCreateSignal() {
   if (!mSignal) {
-    mSignal = new AbortSignal(mOwner, false);
+    mSignal = new AbortSignal(mOwner, false, JS::UndefinedHandleValue);
   }
 
   return mSignal;

dom/webidl/AbortController.webidl

@@ -12,7 +12,7 @@ interface AbortController {
   [Throws]
   constructor();
 
-  readonly attribute AbortSignal signal;
+  [SameObject] readonly attribute AbortSignal signal;
 
-  void abort();
+  void abort(optional any reason);
 };

dom/webidl/AbortSignal.webidl

@@ -9,9 +9,10 @@
 
 [Exposed=(Window,Worker)]
 interface AbortSignal : EventTarget {
-  [NewObject] static AbortSignal abort();
+  [NewObject, Throws] static AbortSignal abort(optional any reason);
 
   readonly attribute boolean aborted;
+  readonly attribute any reason;
 
   attribute EventHandler onabort;
 };

testing/web-platform/meta/dom/abort/event.any.js.ini

@@ -1,44 +0,0 @@
-[event.any.html]
-  [AbortController abort() should fire event synchronously]
-    expected: FAIL
-
-  [AbortController abort(reason) should set signal.reason]
-    expected: FAIL
-
-  [aborting AbortController without reason creates an "AbortError" DOMException]
-    expected: FAIL
-
-  [AbortController abort(undefined) creates an "AbortError" DOMException]
-    expected: FAIL
-
-  [static aborting signal should have right properties]
-    expected: FAIL
-
-  [static aborting signal with reason should set signal.reason]
-    expected: FAIL
-
-  [AbortController abort(null) should set signal.reason]
-    expected: FAIL
-
-
-[event.any.worker.html]
-  [AbortController abort() should fire event synchronously]
-    expected: FAIL
-
-  [AbortController abort(reason) should set signal.reason]
-    expected: FAIL
-
-  [aborting AbortController without reason creates an "AbortError" DOMException]
-    expected: FAIL
-
-  [AbortController abort(undefined) creates an "AbortError" DOMException]
-    expected: FAIL
-
-  [static aborting signal should have right properties]
-    expected: FAIL
-
-  [static aborting signal with reason should set signal.reason]
-    expected: FAIL
-
-  [AbortController abort(null) should set signal.reason]
-    expected: FAIL

testing/web-platform/tests/dom/abort/event.any.js

@@ -139,4 +139,33 @@ test(t => {
   assert_equals(signal.reason, reason, "signal.reason");
 }, "static aborting signal with reason should set signal.reason");
 
+test(t => {
+  const signal = AbortSignal.abort();
+
+  assert_true(
+    signal.reason instanceof DOMException,
+    "signal.reason is a DOMException"
+  );
+  assert_equals(
+    signal.reason,
+    signal.reason,
+    "signal.reason returns the same DOMException"
+  );
+}, "AbortSignal.reason returns the same DOMException");
+
+test(t => {
+  const controller = new AbortController();
+  controller.abort();
+
+  assert_true(
+    controller.signal.reason instanceof DOMException,
+    "signal.reason is a DOMException"
+  );
+  assert_equals(
+    controller.signal.reason,
+    controller.signal.reason,
+    "signal.reason returns the same DOMException"
+  );
+}, "AbortController.signal.reason returns the same DOMException");
+
 done();

testing/web-platform/tests/dom/abort/reason-constructor.html

@@ -0,0 +1,12 @@
+<!DOCTYPE HTML>
+<meta charset=utf-8>
+<title>AbortSignal.reason constructor</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<iframe id="iframe"></iframe>
+<script>
+  test(() => {
+    const aborted = iframe.contentWindow.AbortSignal.abort();
+    assert_equals(aborted.reason.constructor, iframe.contentWindow.DOMException, "DOMException is using the correct global");
+  }, "AbortSignal.reason.constructor should be from iframe");
+</script>