1 files changed, 267 insertions, 0 deletions
diff --git a/dom/workers/WorkerRef.cpp b/dom/workers/WorkerRef.cpp
new file mode 100644
index 0000000000..9ba9841041
--- /dev/null
+++ b/dom/workers/WorkerRef.cpp
@@ -0,0 +1,267 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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 http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/dom/WorkerRef.h"
+
+#include "nsDebug.h"
+#include "WorkerRunnable.h"
+#include "WorkerPrivate.h"
+
+namespace mozilla::dom {
+
+namespace {
+
+// This runnable is used to release the StrongWorkerRef on the worker thread
+// when a ThreadSafeWorkerRef is released.
+class ReleaseRefControlRunnable final : public WorkerControlRunnable {
+ public:
+  ReleaseRefControlRunnable(WorkerPrivate* aWorkerPrivate,
+                            already_AddRefed<StrongWorkerRef> aRef)
+      : WorkerControlRunnable(aWorkerPrivate, "ReleaseRefControlRunnable",
+                              WorkerThread),
+        mRef(std::move(aRef)) {
+    MOZ_ASSERT(mRef);
+  }
+
+  bool PreDispatch(WorkerPrivate* aWorkerPrivate) override { return true; }
+
+  void PostDispatch(WorkerPrivate* aWorkerPrivate,
+                    bool aDispatchResult) override {}
+
+  bool WorkerRun(JSContext* aCx, WorkerPrivate* aWorkerPrivate) override {
+    mRef = nullptr;
+    return true;
+  }
+
+ private:
+  RefPtr<StrongWorkerRef> mRef;
+};
+
+}  // namespace
+
+// ----------------------------------------------------------------------------
+// WorkerRef
+
+WorkerRef::WorkerRef(WorkerPrivate* aWorkerPrivate, const char* aName,
+                     bool aIsPreventingShutdown)
+    :
+#ifdef DEBUG
+      mDebugMutex("WorkerRef"),
+#endif
+      mWorkerPrivate(aWorkerPrivate),
+      mName(aName),
+      mIsPreventingShutdown(aIsPreventingShutdown),
+      mHolding(false) {
+  MOZ_ASSERT(aWorkerPrivate);
+  MOZ_ASSERT(aName);
+
+  aWorkerPrivate->AssertIsOnWorkerThread();
+}
+
+WorkerRef::~WorkerRef() {
+  NS_ASSERT_OWNINGTHREAD(WorkerRef);
+  ReleaseWorker();
+}
+
+void WorkerRef::ReleaseWorker() {
+  if (mHolding) {
+    MOZ_ASSERT(mWorkerPrivate);
+
+    if (mIsPreventingShutdown) {
+      mWorkerPrivate->AssertIsNotPotentiallyLastGCCCRunning();
+    }
+    mWorkerPrivate->RemoveWorkerRef(this);
+    mWorkerPrivate = nullptr;
+
+    mHolding = false;
+  }
+}
+
+bool WorkerRef::HoldWorker(WorkerStatus aStatus) {
+  MOZ_ASSERT(mWorkerPrivate);
+  MOZ_ASSERT(!mHolding);
+
+  if (NS_WARN_IF(!mWorkerPrivate->AddWorkerRef(this, aStatus))) {
+    return false;
+  }
+
+  mHolding = true;
+  return true;
+}
+
+void WorkerRef::Notify() {
+  NS_ASSERT_OWNINGTHREAD(WorkerRef);
+
+  if (!mCallback) {
+    return;
+  }
+
+  MoveOnlyFunction<void()> callback = std::move(mCallback);
+  MOZ_ASSERT(!mCallback);
+
+  callback();
+}
+
+// ----------------------------------------------------------------------------
+// WeakWorkerRef
+
+/* static */
+already_AddRefed<WeakWorkerRef> WeakWorkerRef::Create(
+    WorkerPrivate* aWorkerPrivate, MoveOnlyFunction<void()>&& aCallback) {
+  MOZ_ASSERT(aWorkerPrivate);
+  aWorkerPrivate->AssertIsOnWorkerThread();
+
+  RefPtr<WeakWorkerRef> ref = new WeakWorkerRef(aWorkerPrivate);
+  if (!ref->HoldWorker(Canceling)) {
+    return nullptr;
+  }
+
+  ref->mCallback = std::move(aCallback);
+
+  return ref.forget();
+}
+
+WeakWorkerRef::WeakWorkerRef(WorkerPrivate* aWorkerPrivate)
+    : WorkerRef(aWorkerPrivate, "WeakWorkerRef", false) {}
+
+WeakWorkerRef::~WeakWorkerRef() = default;
+
+void WeakWorkerRef::Notify() {
+  MOZ_ASSERT(mHolding);
+  MOZ_ASSERT(mWorkerPrivate);
+
+  // Notify could drop the last reference to this object. We must keep it alive
+  // in order to call ReleaseWorker() immediately after.
+  RefPtr<WeakWorkerRef> kungFuGrip = this;
+
+  WorkerRef::Notify();
+  ReleaseWorker();
+}
+
+WorkerPrivate* WeakWorkerRef::GetPrivate() const {
+  NS_ASSERT_OWNINGTHREAD(WeakWorkerRef);
+  return mWorkerPrivate;
+}
+
+WorkerPrivate* WeakWorkerRef::GetUnsafePrivate() const {
+  return mWorkerPrivate;
+}
+
+// ----------------------------------------------------------------------------
+// StrongWorkerRef
+
+/* static */
+already_AddRefed<StrongWorkerRef> StrongWorkerRef::Create(
+    WorkerPrivate* const aWorkerPrivate, const char* const aName,
+    MoveOnlyFunction<void()>&& aCallback) {
+  if (RefPtr<StrongWorkerRef> ref =
+          CreateImpl(aWorkerPrivate, aName, Canceling)) {
+    ref->mCallback = std::move(aCallback);
+    return ref.forget();
+  }
+  return nullptr;
+}
+
+/* static */
+already_AddRefed<StrongWorkerRef> StrongWorkerRef::CreateForcibly(
+    WorkerPrivate* const aWorkerPrivate, const char* const aName) {
+  return CreateImpl(aWorkerPrivate, aName, Killing);
+}
+
+/* static */
+already_AddRefed<StrongWorkerRef> StrongWorkerRef::CreateImpl(
+    WorkerPrivate* const aWorkerPrivate, const char* const aName,
+    WorkerStatus const aFailStatus) {
+  MOZ_ASSERT(aWorkerPrivate);
+  MOZ_ASSERT(aName);
+
+  RefPtr<StrongWorkerRef> ref = new StrongWorkerRef(aWorkerPrivate, aName);
+  if (!ref->HoldWorker(aFailStatus)) {
+    return nullptr;
+  }
+
+  return ref.forget();
+}
+
+StrongWorkerRef::StrongWorkerRef(WorkerPrivate* aWorkerPrivate,
+                                 const char* aName)
+    : WorkerRef(aWorkerPrivate, aName, true) {}
+
+StrongWorkerRef::~StrongWorkerRef() = default;
+
+WorkerPrivate* StrongWorkerRef::Private() const {
+  NS_ASSERT_OWNINGTHREAD(StrongWorkerRef);
+  return mWorkerPrivate;
+}
+
+// ----------------------------------------------------------------------------
+// ThreadSafeWorkerRef
+
+ThreadSafeWorkerRef::ThreadSafeWorkerRef(StrongWorkerRef* aRef) : mRef(aRef) {
+  MOZ_ASSERT(aRef);
+  aRef->Private()->AssertIsOnWorkerThread();
+}
+
+ThreadSafeWorkerRef::~ThreadSafeWorkerRef() {
+  // Let's release the StrongWorkerRef on the correct thread.
+  if (!mRef->mWorkerPrivate->IsOnWorkerThread()) {
+    WorkerPrivate* workerPrivate = mRef->mWorkerPrivate;
+    RefPtr<ReleaseRefControlRunnable> r =
+        new ReleaseRefControlRunnable(workerPrivate, mRef.forget());
+    r->Dispatch();
+    return;
+  }
+}
+
+WorkerPrivate* ThreadSafeWorkerRef::Private() const {
+  return mRef->mWorkerPrivate;
+}
+
+// ----------------------------------------------------------------------------
+// IPCWorkerRef
+
+/* static */
+already_AddRefed<IPCWorkerRef> IPCWorkerRef::Create(
+    WorkerPrivate* aWorkerPrivate, const char* aName,
+    MoveOnlyFunction<void()>&& aCallback) {
+  MOZ_ASSERT(aWorkerPrivate);
+  aWorkerPrivate->AssertIsOnWorkerThread();
+
+  RefPtr<IPCWorkerRef> ref = new IPCWorkerRef(aWorkerPrivate, aName);
+  if (!ref->HoldWorker(Canceling)) {
+    return nullptr;
+  }
+  ref->SetActorCount(1);
+  ref->mCallback = std::move(aCallback);
+
+  return ref.forget();
+}
+
+IPCWorkerRef::IPCWorkerRef(WorkerPrivate* aWorkerPrivate, const char* aName)
+    : WorkerRef(aWorkerPrivate, aName, false), mActorCount(0) {}
+
+IPCWorkerRef::~IPCWorkerRef() {
+  NS_ASSERT_OWNINGTHREAD(IPCWorkerRef);
+  // explicit type convertion to avoid undefined behavior of uint32_t overflow.
+  mWorkerPrivate->AdjustNonblockingCCBackgroundActorCount(
+      (int32_t)-mActorCount);
+  ReleaseWorker();
+};
+
+WorkerPrivate* IPCWorkerRef::Private() const {
+  NS_ASSERT_OWNINGTHREAD(IPCWorkerRef);
+  return mWorkerPrivate;
+}
+
+void IPCWorkerRef::SetActorCount(uint32_t aCount) {
+  NS_ASSERT_OWNINGTHREAD(IPCWorkerRef);
+  // explicit type convertion to avoid undefined behavior of uint32_t overflow.
+  mWorkerPrivate->AdjustNonblockingCCBackgroundActorCount((int32_t)aCount -
+                                                          (int32_t)mActorCount);
+  mActorCount = aCount;
+}
+
+}  // namespace mozilla::dom