dom/fs/child/FileSystemShutdownBlocker.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 "fs/FileSystemShutdownBlocker.h"
   8
   9 #include "MainThreadUtils.h"
  10 #include "mozilla/Services.h"
  11 #include "mozilla/dom/quota/QuotaCommon.h"
  12 #include "mozilla/dom/quota/ResultExtensions.h"
  13 #include "nsComponentManagerUtils.h"
  14 #include "nsIAsyncShutdown.h"
  15 #include "nsISupportsImpl.h"
  16 #include "nsIWritablePropertyBag2.h"
  17 #include "nsStringFwd.h"
  18
  19 namespace mozilla::dom::fs {
  20
  21 namespace {
  22
  23 nsString CreateBlockerName() {
  24   const int32_t blockerIdLength = 32;
  25   nsAutoCString blockerId;
  26   blockerId.SetLength(blockerIdLength);
  27   NS_MakeRandomString(blockerId.BeginWriting(), blockerIdLength);
  28
  29   nsString blockerName = u"OPFS_"_ns;
  30   blockerName.Append(NS_ConvertUTF8toUTF16(blockerId));
  31
  32   return blockerName;
  33 }
  34
  35 class FileSystemWritableBlocker : public FileSystemShutdownBlocker {
  36  public:
  37   FileSystemWritableBlocker() : mName(CreateBlockerName()) {}
  38
  39   NS_DECL_ISUPPORTS_INHERITED
  40   NS_DECL_NSIASYNCSHUTDOWNBLOCKER
  41
  42   NS_IMETHODIMP Block() override;
  43
  44   NS_IMETHODIMP Unblock() override;
  45
  46  protected:
  47   virtual ~FileSystemWritableBlocker() = default;
  48
  49   Result<already_AddRefed<nsIAsyncShutdownClient>, nsresult> GetBarrier() const;
  50
  51  private:
  52   const nsString mName;
  53 };
  54
  55 NS_IMPL_ISUPPORTS_INHERITED(FileSystemWritableBlocker,
  56                             FileSystemShutdownBlocker, nsIAsyncShutdownBlocker)
  57
  58 NS_IMETHODIMP FileSystemWritableBlocker::Block() {
  59   MOZ_ASSERT(NS_IsMainThread());
  60   QM_TRY_UNWRAP(nsCOMPtr<nsIAsyncShutdownClient> barrier, GetBarrier());
  61
  62   QM_TRY(MOZ_TO_RESULT(barrier->AddBlocker(
  63       this, NS_ConvertUTF8toUTF16(nsCString(__FILE__)), __LINE__,
  64       NS_ConvertUTF8toUTF16(nsCString(__func__)))));
  65
  66   return NS_OK;
  67 }
  68
  69 NS_IMETHODIMP FileSystemWritableBlocker::Unblock() {
  70   MOZ_ASSERT(NS_IsMainThread());
  71   QM_TRY_UNWRAP(nsCOMPtr<nsIAsyncShutdownClient> barrier, GetBarrier());
  72
  73   MOZ_ASSERT(NS_SUCCEEDED(barrier->RemoveBlocker(this)));
  74
  75   return NS_OK;
  76 }
  77
  78 Result<already_AddRefed<nsIAsyncShutdownClient>, nsresult>
  79 FileSystemWritableBlocker::GetBarrier() const {
  80   nsCOMPtr<nsIAsyncShutdownService> svc = services::GetAsyncShutdownService();
  81   QM_TRY(OkIf(svc), Err(NS_ERROR_FAILURE));
  82
  83   nsCOMPtr<nsIAsyncShutdownClient> barrier;
  84   QM_TRY(MOZ_TO_RESULT(svc->GetXpcomWillShutdown(getter_AddRefs(barrier))));
  85
  86   return barrier.forget();
  87 }
  88
  89 NS_IMETHODIMP
  90 FileSystemWritableBlocker::GetName(nsAString& aName) {
  91   aName = mName;
  92
  93   return NS_OK;
  94 }
  95
  96 NS_IMETHODIMP
  97 FileSystemWritableBlocker::GetState(nsIPropertyBag** aBagOut) {
  98   MOZ_ASSERT(aBagOut);
  99
 100   nsCOMPtr<nsIWritablePropertyBag2> propertyBag =
 101       do_CreateInstance("@mozilla.org/hash-property-bag;1");
 102
 103   QM_TRY(OkIf(propertyBag), NS_ERROR_OUT_OF_MEMORY)
 104
 105   propertyBag.forget(aBagOut);
 106
 107   return NS_OK;
 108 }
 109
 110 NS_IMETHODIMP
 111 FileSystemWritableBlocker::BlockShutdown(
 112     nsIAsyncShutdownClient* /* aBarrier */) {
 113   MOZ_ASSERT(NS_IsMainThread());
 114
 115   return NS_OK;
 116 }
 117
 118 class FileSystemNullBlocker : public FileSystemShutdownBlocker {
 119  public:
 120   NS_IMETHODIMP Block() override { return NS_OK; }
 121
 122   NS_IMETHODIMP Unblock() override { return NS_OK; }
 123
 124  protected:
 125   virtual ~FileSystemNullBlocker() = default;
 126 };
 127
 128 }  // namespace
 129
 130 /* static */
 131 already_AddRefed<FileSystemShutdownBlocker>
 132 FileSystemShutdownBlocker::CreateForWritable() {
 133 // The shutdown blocker watches for xpcom-will-shutdown which is not fired
 134 // during content process shutdown in release builds.
 135 #ifdef DEBUG
 136   if (NS_IsMainThread()) {
 137     RefPtr<FileSystemShutdownBlocker> shutdownBlocker =
 138         new FileSystemWritableBlocker();
 139
 140     return shutdownBlocker.forget();
 141   }
 142 #endif
 143
 144   RefPtr<FileSystemShutdownBlocker> shutdownBlocker =
 145       new FileSystemNullBlocker();
 146
 147   return shutdownBlocker.forget();
 148 }
 149
 150 NS_IMPL_ISUPPORTS(FileSystemShutdownBlocker, nsIAsyncShutdownBlocker)
 151
 152 /* nsIAsyncShutdownBlocker methods */
 153 NS_IMETHODIMP
 154 FileSystemShutdownBlocker::GetName(nsAString& /* aName */) { return NS_OK; }
 155
 156 NS_IMETHODIMP
 157 FileSystemShutdownBlocker::GetState(nsIPropertyBag** /* aBagOut */) {
 158   return NS_OK;
 159 }
 160
 161 NS_IMETHODIMP
 162 FileSystemShutdownBlocker::BlockShutdown(
 163     nsIAsyncShutdownClient* /* aBarrier */) {
 164   return NS_OK;
 165 }
 166
 167 }  // namespace mozilla::dom::fs