Merge mozilla-central to autoland. a=merge CLOSED TREE

dom/fetch/Fetch.cpp

@@ -108,12 +108,8 @@ NS_IMPL_CYCLE_COLLECTING_RELEASE(AbortSignalMainThread)
 
 class AbortSignalProxy;
 
-// An AbortFollower that follows an AbortSignal on a worker thread in order to
-// propagate signaling abort back to the main thread's AbortSignal.
-//
-// This class is separate from AbortSignalProxy below so that its refcount is
-// manipulated only on the worker thread.
 class WorkerSignalFollower final : public AbortFollower {
+ public:
   // This runnable propagates changes from the AbortSignalImpl on workers to the
   // AbortSignalImpl on main-thread.
   class AbortSignalProxyRunnable final : public Runnable {
@@ -131,26 +127,10 @@ class WorkerSignalFollower final : public AbortFollower {
   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
   NS_DECL_CYCLE_COLLECTION_CLASS(WorkerSignalFollower)
 
-  WorkerSignalFollower(AbortSignalProxy* aProxy, AbortSignalImpl* aSignalImpl)
-      : AbortFollower(), mProxy(aProxy) {
-    MOZ_ASSERT(!NS_IsMainThread());
-
-    // Follow the worker thread's signal.
-    Follow(aSignalImpl);
-  }
-
-  void RunAbortAlgorithm() override;
-
-  void Shutdown() {
-    MOZ_ASSERT(!NS_IsMainThread());
-    Unfollow();
-    mProxy = nullptr;
-  }
+  void RunAbortAlgorithm() override {}
 
  private:
   ~WorkerSignalFollower() = default;
-
-  RefPtr<AbortSignalProxy> mProxy;
 };
 
 NS_IMPL_CYCLE_COLLECTION_CLASS(WorkerSignalFollower)
@@ -160,7 +140,6 @@ NS_IMPL_CYCLE_COLLECTING_RELEASE(WorkerSignalFollower)
 
 NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(WorkerSignalFollower)
   AbortFollower::Unlink(static_cast<AbortFollower*>(tmp));
-  tmp->mProxy = nullptr;
 NS_IMPL_CYCLE_COLLECTION_UNLINK_END
 
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(WorkerSignalFollower)
@@ -173,18 +152,7 @@ NS_INTERFACE_MAP_END
 
 // This class orchestrates the proxying of AbortSignal operations between the
 // main thread and a worker thread.
-class AbortSignalProxy final {
-  // An AbortFollower, created/accessed/destroyed only on the worker thread,
-  // that follows the worker-thread AbortSignal and propagates signaling abort
-  // back to the main thread.
-  //
-  // mWorkerSignalFollower maintains a cyclic pointer back at this, that is
-  // broken by this->Shutdown() performed on the worker thread.  That call is
-  // either performed by WeakWorkerRef if its worker is dropped on the floor, or
-  // at end of the worker fetch response (see
-  // WorkerFetchResponseEndBase::WorkerRunInternal).
-  RefPtr<WorkerSignalFollower> mWorkerSignalFollower;
-
+class AbortSignalProxy final : public AbortFollower {
   // This is created and released on the main-thread.
   RefPtr<AbortSignalImpl> mSignalImplMainThread;
 
@@ -198,7 +166,7 @@ class AbortSignalProxy final {
   const bool mAborted;
 
  public:
-  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(AbortSignalProxy)
+  NS_DECL_THREADSAFE_ISUPPORTS
 
   AbortSignalProxy(AbortSignalImpl* aSignalImpl,
                    nsIEventTarget* aMainThreadEventTarget)
@@ -206,10 +174,12 @@ class AbortSignalProxy final {
         mAborted(aSignalImpl->Aborted()) {
     MOZ_ASSERT(!NS_IsMainThread());
     MOZ_ASSERT(mMainThreadEventTarget);
-
-    mWorkerSignalFollower = new WorkerSignalFollower(this, aSignalImpl);
+    Follow(aSignalImpl);
   }
 
+  // AbortFollower
+  void RunAbortAlgorithm() override;
+
   AbortSignalImpl* GetOrCreateSignalImplForMainThread() {
     MOZ_ASSERT(NS_IsMainThread());
     if (!mSignalImplMainThread) {
@@ -220,27 +190,25 @@ class AbortSignalProxy final {
 
   AbortSignalImpl* GetSignalImplForTargetThread() {
     MOZ_ASSERT(!NS_IsMainThread());
-    return mWorkerSignalFollower->Signal();
+    return Signal();
   }
 
   nsIEventTarget* MainThreadEventTarget() { return mMainThreadEventTarget; }
 
   void Shutdown() {
     MOZ_ASSERT(!NS_IsMainThread());
-    mWorkerSignalFollower->Shutdown();
-    mWorkerSignalFollower = nullptr;
+    Unfollow();
   }
 
  private:
   ~AbortSignalProxy() {
-    MOZ_ASSERT(mWorkerSignalFollower == nullptr,
-               "Shutdown() should have been called, on the worker thread, to "
-               "release/free the worker thread's AbortSignal follower by now");
     NS_ProxyRelease("AbortSignalProxy::mSignalImplMainThread",
                     mMainThreadEventTarget, mSignalImplMainThread.forget());
   }
 };
 
+NS_IMPL_ISUPPORTS0(AbortSignalProxy)
+
 NS_IMETHODIMP WorkerSignalFollower::AbortSignalProxyRunnable::Run() {
   MOZ_ASSERT(NS_IsMainThread());
   AbortSignalImpl* signalImpl = mProxy->GetOrCreateSignalImplForMainThread();
@@ -248,12 +216,13 @@ NS_IMETHODIMP WorkerSignalFollower::AbortSignalProxyRunnable::Run() {
   return NS_OK;
 }
 
-void WorkerSignalFollower::RunAbortAlgorithm() {
+void AbortSignalProxy::RunAbortAlgorithm() {
   MOZ_ASSERT(!NS_IsMainThread());
+  using AbortSignalProxyRunnable =
+      WorkerSignalFollower::AbortSignalProxyRunnable;
   RefPtr<AbortSignalProxyRunnable> runnable =
-      new AbortSignalProxyRunnable(mProxy);
-  mProxy->MainThreadEventTarget()->Dispatch(runnable.forget(),
-                                            NS_DISPATCH_NORMAL);
+      new AbortSignalProxyRunnable(this);
+  MainThreadEventTarget()->Dispatch(runnable.forget(), NS_DISPATCH_NORMAL);
 }
 
 class WorkerFetchResolver final : public FetchDriverObserver {