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