Backed out changeset 203ad2fab9aa (bug 1378342)

dom/abort/AbortController.cpp

@@ -12,7 +12,8 @@
 namespace mozilla {
 namespace dom {
 
-NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE(AbortController, mGlobal, mSignal)
+NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE(AbortController, mGlobal, mSignal,
+                                      mFollowingSignal)
 
 NS_IMPL_CYCLE_COLLECTING_ADDREF(AbortController)
 NS_IMPL_CYCLE_COLLECTING_RELEASE(AbortController)
@@ -94,5 +95,33 @@ AbortController::Abort()
   }
 }
 
+void
+AbortController::Follow(AbortSignal& aSignal)
+{
+  AbortSignal::Follower::Follow(&aSignal);
+}
+
+void
+AbortController::Unfollow(AbortSignal& aSignal)
+{
+  if (mFollowingSignal != &aSignal) {
+    return;
+  }
+
+  AbortSignal::Follower::Unfollow();
+}
+
+AbortSignal*
+AbortController::Following() const
+{
+  return mFollowingSignal;
+}
+
+void
+AbortController::Aborted()
+{
+  Abort();
+}
+
 } // dom namespace
 } // mozilla namespace

dom/abort/AbortController.h

@@ -8,19 +8,16 @@
 #define mozilla_dom_AbortController_h
 
 #include "mozilla/dom/BindingDeclarations.h"
-#include "mozilla/ErrorResult.h"
+#include "mozilla/dom/AbortSignal.h"
 #include "nsCycleCollectionParticipant.h"
 #include "nsWrapperCache.h"
 
-class nsIGlobalObject;
-
 namespace mozilla {
 namespace dom {
 
-class AbortSignal;
-
 class AbortController final : public nsISupports
                             , public nsWrapperCache
+                            , public AbortSignal::Follower
 {
 public:
   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
@@ -46,6 +43,19 @@ public:
   void
   Abort();
 
+  void
+  Follow(AbortSignal& aSignal);
+
+  void
+  Unfollow(AbortSignal& aSignal);
+
+  AbortSignal*
+  Following() const;
+
+  // AbortSignal::Follower
+
+  void Aborted() override;
+
 private:
   ~AbortController() = default;
 

dom/abort/AbortSignal.cpp

@@ -67,6 +67,8 @@ AbortSignal::Abort()
   init.mBubbles = false;
   init.mCancelable = false;
 
+  // TODO which kind of event should we dispatch here?
+
   RefPtr<Event> event =
     Event::Constructor(this, NS_LITERAL_STRING("abort"), init);
   event->SetTrusted(true);
@@ -91,6 +93,27 @@ AbortSignal::RemoveFollower(AbortSignal::Follower* aFollower)
   mFollowers.RemoveElement(aFollower);
 }
 
+bool
+AbortSignal::CanAcceptFollower(AbortSignal::Follower* aFollower) const
+{
+  MOZ_DIAGNOSTIC_ASSERT(aFollower);
+
+  if (!mController) {
+    return true;
+  }
+
+  if (aFollower == mController) {
+    return false;
+  }
+
+  AbortSignal* following = mController->Following();
+  if (!following) {
+    return true;
+  }
+
+  return following->CanAcceptFollower(aFollower);
+}
+
 // AbortSignal::Follower
 // ----------------------------------------------------------------------------
 
@@ -104,6 +127,10 @@ AbortSignal::Follower::Follow(AbortSignal* aSignal)
 {
   MOZ_DIAGNOSTIC_ASSERT(aSignal);
 
+  if (!aSignal->CanAcceptFollower(this)) {
+    return;
+  }
+
   Unfollow();
 
   mFollowingSignal = aSignal;

dom/abort/AbortSignal.h

@@ -59,6 +59,9 @@ public:
   void
   RemoveFollower(Follower* aFollower);
 
+  bool
+  CanAcceptFollower(Follower* aFollower) const;
+
 private:
   ~AbortSignal() = default;
 

dom/abort/tests/file_abort_controller.html

@@ -32,6 +32,49 @@ function testUpdateData() {
   next();
 }
  
+function testFollowingOurself() {
+  // Let's follow ourself
+  var ac = new AbortController();
+  ac.follow(ac.signal);
+ 
+  ac.abort();
+  is(ac.signal.aborted, true, "Signal is aborted");
+ 
+  next();
+}
+ 
+function testFollowingOther() {
+  // Let's follow another one
+  var ac1 = new AbortController();
+  var ac2 = new AbortController();
+  ac1.follow(ac2.signal);
+ 
+  ac2.abort();
+ 
+  is(ac1.signal.aborted, true, "Signal is aborted");
+  is(ac2.signal.aborted, true, "Signal is aborted");
+ 
+  next();
+}
+
+function testFollowingLoop() {
+  // ac1 -> ac2 -> ac3 -> ac1
+  var ac1 = new AbortController();
+  var ac2 = new AbortController();
+  var ac3 = new AbortController();
+  ac1.follow(ac2.signal);
+  ac2.follow(ac3.signal);
+  ac3.follow(ac1.signal);
+ 
+  ac3.abort();
+ 
+  is(ac1.signal.aborted, true, "Signal is aborted");
+  is(ac2.signal.aborted, true, "Signal is aborted");
+  is(ac3.signal.aborted, true, "Signal is aborted");
+ 
+  next();
+}
+ 
 function testAbortEvent() {
   var ac = new AbortController();
   ac.signal.onabort = function(e) {
@@ -88,6 +131,11 @@ var steps = [
   testWebIDL,
   testUpdateData,
 
+  // Following algorithm
+  testFollowingOurself,
+  testFollowingOther,
+  testFollowingLoop,
+
   // Event propagation
   testAbortEvent,
 

dom/webidl/AbortController.webidl

@@ -13,4 +13,6 @@ interface AbortController {
   readonly attribute AbortSignal signal;
 
   void abort();
+  void follow(AbortSignal signal);
+  void unfollow(AbortSignal signal);
 };