1 files changed, 172 insertions, 0 deletions
diff --git a/dom/webscheduling/WebTaskScheduler.h b/dom/webscheduling/WebTaskScheduler.h
new file mode 100644
index 0000000000..fcddd09d36
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+++ b/dom/webscheduling/WebTaskScheduler.h
@@ -0,0 +1,172 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=2:
+ */
+/* 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/. */
+
+#ifndef mozilla_dom_WebTaskScheduler_h
+#define mozilla_dom_WebTaskScheduler_h
+
+#include "nsThreadUtils.h"
+#include "nsPIDOMWindow.h"
+#include "nsWrapperCache.h"
+#include "nsClassHashtable.h"
+
+#include "mozilla/dom/Promise.h"
+#include "mozilla/dom/AbortFollower.h"
+#include "mozilla/dom/TimeoutHandler.h"
+#include "mozilla/dom/WebTaskSchedulingBinding.h"
+
+namespace mozilla::dom {
+class WebTask : public LinkedListElement<RefPtr<WebTask>>,
+                public AbortFollower,
+                public SupportsWeakPtr {
+  friend class WebTaskScheduler;
+
+ public:
+  MOZ_CAN_RUN_SCRIPT bool Run();
+
+  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
+
+  NS_DECL_CYCLE_COLLECTION_CLASS(WebTask)
+  WebTask(uint32_t aEnqueueOrder, SchedulerPostTaskCallback& aCallback,
+          Promise* aPromise)
+      : mEnqueueOrder(aEnqueueOrder),
+        mCallback(&aCallback),
+        mPromise(aPromise),
+        mHasScheduled(false) {}
+
+  void RunAbortAlgorithm() override;
+
+  bool HasScheduled() const { return mHasScheduled; }
+
+  uint32_t EnqueueOrder() const { return mEnqueueOrder; }
+
+ private:
+  void SetHasScheduled(bool aHasScheduled) { mHasScheduled = aHasScheduled; }
+
+  uint32_t mEnqueueOrder;
+
+  RefPtr<SchedulerPostTaskCallback> mCallback;
+  RefPtr<Promise> mPromise;
+
+  bool mHasScheduled;
+
+  ~WebTask() = default;
+};
+
+class WebTaskQueue {
+ public:
+  WebTaskQueue() = default;
+
+  TaskPriority Priority() const { return mPriority; }
+  void SetPriority(TaskPriority aNewPriority) { mPriority = aNewPriority; }
+
+  LinkedList<RefPtr<WebTask>>& Tasks() { return mTasks; }
+
+  void AddTask(WebTask* aTask) { mTasks.insertBack(aTask); }
+
+  // TODO: To optimize it, we could have the scheduled and unscheduled
+  // tasks stored separately.
+  WebTask* GetFirstScheduledTask() {
+    for (const auto& task : mTasks) {
+      if (task->HasScheduled()) {
+        return task;
+      }
+    }
+    return nullptr;
+  }
+
+  ~WebTaskQueue() { mTasks.clear(); }
+
+ private:
+  TaskPriority mPriority = TaskPriority::User_visible;
+  LinkedList<RefPtr<WebTask>> mTasks;
+};
+
+class WebTaskSchedulerMainThread;
+class WebTaskSchedulerWorker;
+
+class WebTaskScheduler : public nsWrapperCache, public SupportsWeakPtr {
+  friend class DelayedWebTaskHandler;
+
+ public:
+  NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING(WebTaskScheduler)
+  NS_DECL_CYCLE_COLLECTION_NATIVE_WRAPPERCACHE_CLASS(WebTaskScheduler)
+
+  static already_AddRefed<WebTaskSchedulerMainThread> CreateForMainThread(
+      nsGlobalWindowInner* aWindow);
+
+  static already_AddRefed<WebTaskSchedulerWorker> CreateForWorker(
+      WorkerPrivate* aWorkerPrivate);
+
+  explicit WebTaskScheduler(nsIGlobalObject* aParent);
+
+  already_AddRefed<Promise> PostTask(SchedulerPostTaskCallback& aCallback,
+                                     const SchedulerPostTaskOptions& aOptions);
+
+  nsIGlobalObject* GetParentObject() const { return mParent; }
+
+  virtual JSObject* WrapObject(JSContext* cx,
+                               JS::Handle<JSObject*> aGivenProto) override;
+
+  WebTask* GetNextTask() const;
+
+  void Disconnect();
+
+  void RunTaskSignalPriorityChange(TaskSignal* aTaskSignal);
+
+ protected:
+  virtual ~WebTaskScheduler() = default;
+  nsCOMPtr<nsIGlobalObject> mParent;
+
+  uint32_t mNextEnqueueOrder;
+
+ private:
+  already_AddRefed<WebTask> CreateTask(
+      WebTaskQueue& aQueue, const Optional<OwningNonNull<AbortSignal>>& aSignal,
+      SchedulerPostTaskCallback& aCallback, Promise* aPromise);
+
+  bool QueueTask(WebTask* aTask);
+
+  WebTaskQueue& SelectTaskQueue(
+      const Optional<OwningNonNull<AbortSignal>>& aSignal,
+      const Optional<TaskPriority>& aPriority);
+
+  virtual nsresult SetTimeoutForDelayedTask(WebTask* aTask,
+                                            uint64_t aDelay) = 0;
+  virtual bool DispatchEventLoopRunnable() = 0;
+
+  nsClassHashtable<nsUint32HashKey, WebTaskQueue> mStaticPriorityTaskQueues;
+  nsClassHashtable<nsPtrHashKey<TaskSignal>, WebTaskQueue>
+      mDynamicPriorityTaskQueues;
+};
+
+class DelayedWebTaskHandler final : public TimeoutHandler {
+ public:
+  DelayedWebTaskHandler(JSContext* aCx, WebTaskScheduler* aScheduler,
+                        WebTask* aTask)
+      : TimeoutHandler(aCx), mScheduler(aScheduler), mWebTask(aTask) {}
+
+  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
+  NS_DECL_CYCLE_COLLECTION_CLASS(DelayedWebTaskHandler)
+
+  MOZ_CAN_RUN_SCRIPT bool Call(const char* /* unused */) override {
+    if (mScheduler && mWebTask) {
+      MOZ_ASSERT(!mWebTask->HasScheduled());
+      if (!mScheduler->QueueTask(mWebTask)) {
+        return false;
+      }
+    }
+    return true;
+  }
+
+ private:
+  ~DelayedWebTaskHandler() override = default;
+  WeakPtr<WebTaskScheduler> mScheduler;
+  // WebTask gets added to WebTaskQueue, and WebTaskQueue keeps its alive.
+  WeakPtr<WebTask> mWebTask;
+};
+}  // namespace mozilla::dom
+#endif