dom/serviceworkers/ServiceWorkerJobQueue.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 "ServiceWorkerJobQueue.h"
   8
   9 #include "nsThreadUtils.h"
  10 #include "ServiceWorkerJob.h"
  11 #include "mozilla/dom/WorkerCommon.h"
  12
  13 namespace mozilla {
  14 namespace dom {
  15
  16 class ServiceWorkerJobQueue::Callback final
  17     : public ServiceWorkerJob::Callback {
  18   RefPtr<ServiceWorkerJobQueue> mQueue;
  19
  20   ~Callback() = default;
  21
  22  public:
  23   explicit Callback(ServiceWorkerJobQueue* aQueue) : mQueue(aQueue) {
  24     MOZ_ASSERT(NS_IsMainThread());
  25     MOZ_ASSERT(mQueue);
  26   }
  27
  28   virtual void JobFinished(ServiceWorkerJob* aJob,
  29                            ErrorResult& aStatus) override {
  30     MOZ_ASSERT(NS_IsMainThread());
  31     mQueue->JobFinished(aJob);
  32   }
  33
  34   virtual void JobDiscarded(ErrorResult&) override {
  35     // no-op; nothing to do.
  36   }
  37
  38   NS_INLINE_DECL_REFCOUNTING(ServiceWorkerJobQueue::Callback, override)
  39 };
  40
  41 ServiceWorkerJobQueue::~ServiceWorkerJobQueue() {
  42   MOZ_ASSERT(NS_IsMainThread());
  43   MOZ_ASSERT(mJobList.IsEmpty());
  44 }
  45
  46 void ServiceWorkerJobQueue::JobFinished(ServiceWorkerJob* aJob) {
  47   MOZ_ASSERT(NS_IsMainThread());
  48   MOZ_ASSERT(aJob);
  49
  50   // XXX There are some corner cases where jobs can double-complete.  Until
  51   // we track all these down we do a non-fatal assert in debug builds and
  52   // a runtime check to verify the queue is in the correct state.
  53   NS_ASSERTION(!mJobList.IsEmpty(),
  54                "Job queue should contain the job that just completed.");
  55   NS_ASSERTION(mJobList.SafeElementAt(0, nullptr) == aJob,
  56                "Job queue should contain the job that just completed.");
  57   if (NS_WARN_IF(mJobList.SafeElementAt(0, nullptr) != aJob)) {
  58     return;
  59   }
  60
  61   mJobList.RemoveElementAt(0);
  62
  63   if (mJobList.IsEmpty()) {
  64     return;
  65   }
  66
  67   RunJob();
  68 }
  69
  70 void ServiceWorkerJobQueue::RunJob() {
  71   MOZ_ASSERT(NS_IsMainThread());
  72   MOZ_ASSERT(!mJobList.IsEmpty());
  73   MOZ_ASSERT(mJobList[0]->GetState() == ServiceWorkerJob::State::Initial);
  74
  75   RefPtr<Callback> callback = new Callback(this);
  76   mJobList[0]->Start(callback);
  77 }
  78
  79 ServiceWorkerJobQueue::ServiceWorkerJobQueue() {
  80   MOZ_ASSERT(NS_IsMainThread());
  81 }
  82
  83 void ServiceWorkerJobQueue::ScheduleJob(ServiceWorkerJob* aJob) {
  84   MOZ_ASSERT(NS_IsMainThread());
  85   MOZ_ASSERT(aJob);
  86   MOZ_ASSERT(!mJobList.Contains(aJob));
  87
  88   if (mJobList.IsEmpty()) {
  89     mJobList.AppendElement(aJob);
  90     RunJob();
  91     return;
  92   }
  93
  94   MOZ_ASSERT(mJobList[0]->GetState() == ServiceWorkerJob::State::Started);
  95
  96   RefPtr<ServiceWorkerJob>& tailJob = mJobList[mJobList.Length() - 1];
  97   if (!tailJob->ResultCallbacksInvoked() && aJob->IsEquivalentTo(tailJob)) {
  98     tailJob->StealResultCallbacksFrom(aJob);
  99     return;
 100   }
 101
 102   mJobList.AppendElement(aJob);
 103 }
 104
 105 void ServiceWorkerJobQueue::CancelAll() {
 106   MOZ_ASSERT(NS_IsMainThread());
 107
 108   for (RefPtr<ServiceWorkerJob>& job : mJobList) {
 109     job->Cancel();
 110   }
 111
 112   // Remove jobs that are queued but not started since they should never
 113   // run after being canceled.  This means throwing away all jobs except
 114   // for the job at the front of the list.
 115   if (!mJobList.IsEmpty()) {
 116     MOZ_ASSERT(mJobList[0]->GetState() == ServiceWorkerJob::State::Started);
 117     mJobList.TruncateLength(1);
 118   }
 119 }
 120
 121 }  // namespace dom
 122 }  // namespace mozilla