dom/webscheduling/WebTaskScheduler.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "nsTHashMap.h"
   8 #include "WebTaskScheduler.h"
   9 #include "WebTaskSchedulerWorker.h"
  10 #include "WebTaskSchedulerMainThread.h"
  11 #include "TaskSignal.h"
  12 #include "nsGlobalWindowInner.h"
  13
  14 #include "mozilla/dom/WorkerPrivate.h"
  15 #include "mozilla/dom/TimeoutManager.h"
  16
  17 namespace mozilla::dom {
  18
  19 inline void ImplCycleCollectionTraverse(
  20     nsCycleCollectionTraversalCallback& aCallback, WebTaskQueue& aQueue,
  21     const char* aName, uint32_t aFlags = 0) {
  22   ImplCycleCollectionTraverse(aCallback, aQueue.Tasks(), aName, aFlags);
  23 }
  24
  25 NS_IMPL_CYCLE_COLLECTION_CLASS(WebTask)
  26
  27 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(WebTask)
  28   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mCallback)
  29   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mPromise)
  30 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
  31
  32 NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(WebTask)
  33   NS_IMPL_CYCLE_COLLECTION_UNLINK(mCallback)
  34   NS_IMPL_CYCLE_COLLECTION_UNLINK(mPromise)
  35   NS_IMPL_CYCLE_COLLECTION_UNLINK_WEAK_PTR
  36 NS_IMPL_CYCLE_COLLECTION_UNLINK_END
  37
  38 NS_IMPL_CYCLE_COLLECTING_ADDREF(WebTask)
  39 NS_IMPL_CYCLE_COLLECTING_RELEASE(WebTask)
  40
  41 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(WebTask)
  42   NS_INTERFACE_MAP_ENTRY(nsISupports)
  43 NS_INTERFACE_MAP_END
  44
  45 NS_IMPL_CYCLE_COLLECTION(DelayedWebTaskHandler)
  46
  47 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(DelayedWebTaskHandler)
  48   NS_INTERFACE_MAP_ENTRY(nsISupports)
  49 NS_INTERFACE_MAP_END
  50
  51 NS_IMPL_CYCLE_COLLECTING_ADDREF(DelayedWebTaskHandler)
  52 NS_IMPL_CYCLE_COLLECTING_RELEASE(DelayedWebTaskHandler)
  53
  54 void WebTask::RunAbortAlgorithm() {
  55   // no-op if WebTask::Run has been called already
  56   if (mPromise->State() == Promise::PromiseState::Pending) {
  57     // There are two things that can keep a WebTask alive, either the abort
  58     // signal or WebTaskQueue.
  59     // It's possible that this task get cleared out from the WebTaskQueue first,
  60     // and then the abort signal get aborted. For example, the callback function
  61     // was async and there's a signal.abort() call in the callback.
  62     if (isInList()) {
  63       remove();
  64     }
  65
  66     AutoJSAPI jsapi;
  67     if (!jsapi.Init(mPromise->GetGlobalObject())) {
  68       mPromise->MaybeReject(NS_ERROR_UNEXPECTED);
  69     } else {
  70       JSContext* cx = jsapi.cx();
  71       JS::Rooted<JS::Value> reason(cx);
  72       Signal()->GetReason(cx, &reason);
  73       mPromise->MaybeReject(reason);
  74     }
  75   }
  76
  77   MOZ_ASSERT(!isInList());
  78 }
  79
  80 bool WebTask::Run() {
  81   MOZ_ASSERT(HasScheduled());
  82   remove();
  83
  84   ErrorResult error;
  85
  86   nsIGlobalObject* global = mPromise->GetGlobalObject();
  87   if (!global || global->IsDying()) {
  88     return false;
  89   }
  90
  91   AutoJSAPI jsapi;
  92   if (!jsapi.Init(global)) {
  93     return false;
  94   }
  95
  96   JS::Rooted<JS::Value> returnVal(jsapi.cx());
  97
  98   MOZ_ASSERT(mPromise->State() == Promise::PromiseState::Pending);
  99
 100   MOZ_KnownLive(mCallback)->Call(&returnVal, error, "WebTask",
 101                                  CallbackFunction::eRethrowExceptions);
 102
 103   error.WouldReportJSException();
 104
 105 #ifdef DEBUG
 106   Promise::PromiseState promiseState = mPromise->State();
 107
 108   // If the state is Rejected, it means the above Call triggers the
 109   // RunAbortAlgorithm method and rejected the promise
 110   MOZ_ASSERT_IF(promiseState != Promise::PromiseState::Pending,
 111                 promiseState == Promise::PromiseState::Rejected);
 112 #endif
 113
 114   if (error.Failed()) {
 115     if (!error.IsUncatchableException()) {
 116       mPromise->MaybeReject(std::move(error));
 117     } else {
 118       error.SuppressException();
 119     }
 120   } else {
 121     mPromise->MaybeResolve(returnVal);
 122   }
 123
 124   MOZ_ASSERT(!isInList());
 125   return true;
 126 }
 127
 128 NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE(WebTaskScheduler, mParent,
 129                                       mStaticPriorityTaskQueues,
 130                                       mDynamicPriorityTaskQueues)
 131
 132 /* static */
 133 already_AddRefed<WebTaskSchedulerMainThread>
 134 WebTaskScheduler::CreateForMainThread(nsGlobalWindowInner* aWindow) {
 135   RefPtr<WebTaskSchedulerMainThread> scheduler =
 136       new WebTaskSchedulerMainThread(aWindow->AsGlobal());
 137   return scheduler.forget();
 138 }
 139
 140 already_AddRefed<WebTaskSchedulerWorker> WebTaskScheduler::CreateForWorker(
 141     WorkerPrivate* aWorkerPrivate) {
 142   aWorkerPrivate->AssertIsOnWorkerThread();
 143   RefPtr<WebTaskSchedulerWorker> scheduler =
 144       new WebTaskSchedulerWorker(aWorkerPrivate);
 145   return scheduler.forget();
 146 }
 147
 148 WebTaskScheduler::WebTaskScheduler(nsIGlobalObject* aParent)
 149     : mParent(aParent), mNextEnqueueOrder(1) {
 150   MOZ_ASSERT(aParent);
 151 }
 152
 153 JSObject* WebTaskScheduler::WrapObject(JSContext* cx,
 154                                        JS::Handle<JSObject*> aGivenProto) {
 155   return Scheduler_Binding::Wrap(cx, this, aGivenProto);
 156 }
 157
 158 already_AddRefed<Promise> WebTaskScheduler::PostTask(
 159     SchedulerPostTaskCallback& aCallback,
 160     const SchedulerPostTaskOptions& aOptions) {
 161   const Optional<OwningNonNull<AbortSignal>>& taskSignal = aOptions.mSignal;
 162   const Optional<TaskPriority>& taskPriority = aOptions.mPriority;
 163
 164   ErrorResult rv;
 165   // Instead of making WebTaskScheduler::PostTask throws, we always
 166   // create the promise and return it. This is because we need to
 167   // create the promise explicitly to be able to reject it with
 168   // signal's reason.
 169   RefPtr<Promise> promise = Promise::Create(mParent, rv);
 170   if (rv.Failed()) {
 171     return nullptr;
 172   }
 173
 174   nsIGlobalObject* global = GetParentObject();
 175   if (!global || global->IsDying()) {
 176     promise->MaybeRejectWithNotSupportedError("Current window is detached");
 177     return promise.forget();
 178   }
 179
 180   if (taskSignal.WasPassed()) {
 181     AbortSignal& signalValue = taskSignal.Value();
 182
 183     if (signalValue.Aborted()) {
 184       AutoJSAPI jsapi;
 185       if (!jsapi.Init(global)) {
 186         promise->MaybeReject(NS_ERROR_UNEXPECTED);
 187         return promise.forget();
 188       }
 189
 190       JSContext* cx = jsapi.cx();
 191       JS::Rooted<JS::Value> reason(cx);
 192       signalValue.GetReason(cx, &reason);
 193       promise->MaybeReject(reason);
 194       return promise.forget();
 195     }
 196   }
 197
 198   // Let queue be the result of selecting the scheduler task queue for scheduler
 199   // given signal and priority.
 200   WebTaskQueue& taskQueue = SelectTaskQueue(taskSignal, taskPriority);
 201
 202   uint64_t delay = aOptions.mDelay;
 203
 204   RefPtr<WebTask> task = CreateTask(taskQueue, taskSignal, aCallback, promise);
 205   if (delay > 0) {
 206     nsresult rv = SetTimeoutForDelayedTask(task, delay);
 207     if (NS_FAILED(rv)) {
 208       promise->MaybeRejectWithUnknownError(
 209           "Failed to setup timeout for delayed task");
 210     }
 211     return promise.forget();
 212   }
 213
 214   if (!QueueTask(task)) {
 215     MOZ_ASSERT(task->isInList());
 216     task->remove();
 217
 218     promise->MaybeRejectWithNotSupportedError("Unable to queue the task");
 219     return promise.forget();
 220   }
 221
 222   return promise.forget();
 223 }
 224
 225 already_AddRefed<WebTask> WebTaskScheduler::CreateTask(
 226     WebTaskQueue& aQueue, const Optional<OwningNonNull<AbortSignal>>& aSignal,
 227     SchedulerPostTaskCallback& aCallback, Promise* aPromise) {
 228   uint32_t nextEnqueueOrder = mNextEnqueueOrder;
 229   ++mNextEnqueueOrder;
 230
 231   RefPtr<WebTask> task = new WebTask(nextEnqueueOrder, aCallback, aPromise);
 232
 233   aQueue.AddTask(task);
 234
 235   if (aSignal.WasPassed()) {
 236     AbortSignal& signalValue = aSignal.Value();
 237     task->Follow(&signalValue);
 238   }
 239
 240   return task.forget();
 241 }
 242
 243 bool WebTaskScheduler::QueueTask(WebTask* aTask) {
 244   if (!DispatchEventLoopRunnable()) {
 245     return false;
 246   }
 247   MOZ_ASSERT(!aTask->HasScheduled());
 248   aTask->SetHasScheduled(true);
 249   return true;
 250 }
 251
 252 WebTask* WebTaskScheduler::GetNextTask() const {
 253   // We first combine queues from both mStaticPriorityTaskQueues and
 254   // mDynamicPriorityTaskQueues into a single hash map which the
 255   // keys are the priorities and the values are all the queues that
 256   // belong to this priority.
 257   //
 258   // Then From the queues which
 259   //   1. Have scheduled tasks
 260   //   2. Its priority is not less than any other queues' priority
 261   // We pick the task which has the smallest enqueue order.
 262   nsTHashMap<nsUint32HashKey, nsTArray<WebTaskQueue*>> allQueues;
 263
 264   for (auto iter = mStaticPriorityTaskQueues.ConstIter(); !iter.Done();
 265        iter.Next()) {
 266     const auto& queue = iter.Data();
 267     if (!queue->Tasks().isEmpty() && queue->GetFirstScheduledTask()) {
 268       nsTArray<WebTaskQueue*>& queuesForThisPriority =
 269           allQueues.LookupOrInsert(static_cast<uint32_t>(iter.Key()));
 270       queuesForThisPriority.AppendElement(queue.get());
 271     }
 272   }
 273
 274   for (auto iter = mDynamicPriorityTaskQueues.ConstIter(); !iter.Done();
 275        iter.Next()) {
 276     const auto& queue = iter.Data();
 277     if (!queue->Tasks().isEmpty() && queue->GetFirstScheduledTask()) {
 278       nsTArray<WebTaskQueue*>& queuesForThisPriority = allQueues.LookupOrInsert(
 279           static_cast<uint32_t>(iter.Key()->Priority()));
 280       queuesForThisPriority.AppendElement(queue.get());
 281     }
 282   }
 283
 284   if (allQueues.IsEmpty()) {
 285     return nullptr;
 286   }
 287
 288   for (uint32_t priority = static_cast<uint32_t>(TaskPriority::User_blocking);
 289        priority < static_cast<uint32_t>(TaskPriority::EndGuard_); ++priority) {
 290     if (auto queues = allQueues.Lookup(priority)) {
 291       WebTaskQueue* oldestQueue = nullptr;
 292       MOZ_ASSERT(!queues.Data().IsEmpty());
 293       for (auto& webTaskQueue : queues.Data()) {
 294         MOZ_ASSERT(webTaskQueue->GetFirstScheduledTask());
 295         if (!oldestQueue) {
 296           oldestQueue = webTaskQueue;
 297         } else {
 298           WebTask* firstScheduledRunnableForCurrentQueue =
 299               webTaskQueue->GetFirstScheduledTask();
 300           WebTask* firstScheduledRunnableForOldQueue =
 301               oldestQueue->GetFirstScheduledTask();
 302           if (firstScheduledRunnableForOldQueue->EnqueueOrder() >
 303               firstScheduledRunnableForCurrentQueue->EnqueueOrder()) {
 304             oldestQueue = webTaskQueue;
 305           }
 306         }
 307       }
 308       MOZ_ASSERT(oldestQueue);
 309       return oldestQueue->GetFirstScheduledTask();
 310     }
 311   }
 312   return nullptr;
 313 }
 314
 315 void WebTaskScheduler::Disconnect() {
 316   mStaticPriorityTaskQueues.Clear();
 317   mDynamicPriorityTaskQueues.Clear();
 318 }
 319
 320 void WebTaskScheduler::RunTaskSignalPriorityChange(TaskSignal* aTaskSignal) {
 321   WebTaskQueue* const taskQueue = mDynamicPriorityTaskQueues.Get(aTaskSignal);
 322   MOZ_ASSERT(taskQueue);
 323   taskQueue->SetPriority(aTaskSignal->Priority());
 324 }
 325
 326 WebTaskQueue& WebTaskScheduler::SelectTaskQueue(
 327     const Optional<OwningNonNull<AbortSignal>>& aSignal,
 328     const Optional<TaskPriority>& aPriority) {
 329   bool useSignal = !aPriority.WasPassed() && aSignal.WasPassed() &&
 330                    aSignal.Value().IsTaskSignal();
 331
 332   if (useSignal) {
 333     TaskSignal* taskSignal = static_cast<TaskSignal*>(&(aSignal.Value()));
 334     WebTaskQueue* const taskQueue =
 335         mDynamicPriorityTaskQueues.GetOrInsertNew(taskSignal);
 336     taskQueue->SetPriority(taskSignal->Priority());
 337     taskSignal->SetWebTaskScheduler(this);
 338     MOZ_ASSERT(mDynamicPriorityTaskQueues.Contains(taskSignal));
 339
 340     return *taskQueue;
 341   }
 342
 343   TaskPriority taskPriority =
 344       aPriority.WasPassed() ? aPriority.Value() : TaskPriority::User_visible;
 345
 346   WebTaskQueue* const taskQueue = mStaticPriorityTaskQueues.GetOrInsertNew(
 347       static_cast<uint32_t>(taskPriority));
 348   taskQueue->SetPriority(taskPriority);
 349   MOZ_ASSERT(
 350       mStaticPriorityTaskQueues.Contains(static_cast<uint32_t>(taskPriority)));
 351   return *taskQueue;
 352 }
 353
 354 }  // namespace mozilla::dom