tor-browser

The Tor Browser
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CacheChild.cpp (3883B)

      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 "mozilla/dom/cache/CacheChild.h"
      8 
      9 #include "CacheWorkerRef.h"
     10 #include "mozilla/dom/cache/ActorUtils.h"
     11 #include "mozilla/dom/cache/Cache.h"
     12 #include "mozilla/dom/cache/CacheOpChild.h"
     13 
     14 namespace mozilla::dom::cache {
     15 
     16 // Declared in ActorUtils.h
     17 already_AddRefed<PCacheChild> AllocPCacheChild(ActorChild* aParentActor) {
     18  return MakeAndAddRef<CacheChild>(aParentActor);
     19 }
     20 
     21 // Declared in ActorUtils.h
     22 void DeallocPCacheChild(PCacheChild* aActor) { delete aActor; }
     23 
     24 CacheChild::CacheChild(ActorChild* aParentActor)
     25    : mParentActor(aParentActor),
     26      mListener(nullptr),
     27      mLocked(false),
     28      mDelayedDestroy(false) {
     29  MOZ_COUNT_CTOR(cache::CacheChild);
     30 }
     31 
     32 CacheChild::~CacheChild() {
     33  MOZ_COUNT_DTOR(cache::CacheChild);
     34  NS_ASSERT_OWNINGTHREAD(CacheChild);
     35  MOZ_DIAGNOSTIC_ASSERT(!mListener);
     36  MOZ_DIAGNOSTIC_ASSERT(!mLocked);
     37 }
     38 
     39 void CacheChild::SetListener(CacheChildListener* aListener) {
     40  NS_ASSERT_OWNINGTHREAD(CacheChild);
     41  MOZ_DIAGNOSTIC_ASSERT(!mListener);
     42  mListener = aListener;
     43  MOZ_DIAGNOSTIC_ASSERT(mListener);
     44 }
     45 
     46 void CacheChild::ClearListener() {
     47  NS_ASSERT_OWNINGTHREAD(CacheChild);
     48  MOZ_DIAGNOSTIC_ASSERT(mListener);
     49  mListener = nullptr;
     50 }
     51 
     52 void CacheChild::StartDestroyFromListener() {
     53  NS_ASSERT_OWNINGTHREAD(CacheChild);
     54 
     55  // The listener should be held alive by any async operations, so if it
     56  // is going away then there must not be any child actors.  This in turn
     57  // ensures that StartDestroy() will not trigger the delayed path.
     58  MOZ_DIAGNOSTIC_ASSERT(NumChildActors() == 0);
     59  StartDestroy();
     60 }
     61 
     62 void CacheChild::DestroyInternal() {
     63  CacheChildListener* listener = mListener;
     64 
     65  // StartDestroy() can get called from either Cache or the WorkerRef.
     66  // Theoretically we can get double called if the right race happens.  Handle
     67  // that by just ignoring the second StartDestroy() call.
     68  if (!listener) {
     69    return;
     70  }
     71 
     72  listener->OnActorDestroy(this);
     73 
     74  // Cache listener should call ClearListener() in OnActorDestroy()
     75  MOZ_DIAGNOSTIC_ASSERT(!mListener);
     76 
     77  // Start actor destruction from parent process
     78  QM_WARNONLY_TRY(OkIf(SendTeardown()));
     79 }
     80 
     81 void CacheChild::StartDestroy() {
     82  NS_ASSERT_OWNINGTHREAD(CacheChild);
     83 
     84  if (NumChildActors() != 0 || mLocked) {
     85    mDelayedDestroy = true;
     86    return;
     87  }
     88 
     89  DestroyInternal();
     90 }
     91 
     92 void CacheChild::ActorDestroy(ActorDestroyReason aReason) {
     93  NS_ASSERT_OWNINGTHREAD(CacheChild);
     94  CacheChildListener* listener = mListener;
     95  if (listener) {
     96    listener->OnActorDestroy(this);
     97    // Cache listener should call ClearListener() in OnActorDestroy()
     98    MOZ_DIAGNOSTIC_ASSERT(!mListener);
     99  }
    100 
    101  if (mParentActor) {
    102    mParentActor->NoteDeletedActor();
    103  }
    104 
    105  RemoveWorkerRef();
    106 }
    107 
    108 void CacheChild::NoteDeletedActor() {
    109  // Check to see if DestroyInternal was delayed because there were still active
    110  // CacheOpChilds when StartDestroy was called from WorkerRef notification. If
    111  // the last CacheOpChild is getting destructed; it's the time for us to
    112  // SendTearDown to the other side.
    113  if (NumChildActors() == 0 && mDelayedDestroy && !mLocked) DestroyInternal();
    114 }
    115 
    116 already_AddRefed<PCacheOpChild> CacheChild::AllocPCacheOpChild(
    117    const CacheOpArgs& aOpArgs) {
    118  MOZ_CRASH("CacheOpChild should be manually constructed.");
    119  return nullptr;
    120 }
    121 
    122 void CacheChild::Lock() {
    123  NS_ASSERT_OWNINGTHREAD(CacheChild);
    124  MOZ_DIAGNOSTIC_ASSERT(!mLocked);
    125  mLocked = true;
    126 }
    127 
    128 void CacheChild::Unlock() {
    129  NS_ASSERT_OWNINGTHREAD(CacheChild);
    130  MOZ_DIAGNOSTIC_ASSERT(mLocked);
    131  mLocked = false;
    132 }
    133 
    134 }  // namespace mozilla::dom::cache