xpcom/base/ClearOnShutdown.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 "mozilla/ClearOnShutdown.h"
   8
   9 namespace mozilla {
  10 namespace ClearOnShutdown_Internal {
  11
  12 Array<StaticAutoPtr<ShutdownList>,
  13       static_cast<size_t>(ShutdownPhase::ShutdownPhase_Length)>
  14     sShutdownObservers;
  15 ShutdownPhase sCurrentClearOnShutdownPhase = ShutdownPhase::NotInShutdown;
  16
  17 void InsertIntoShutdownList(ShutdownObserver* aObserver, ShutdownPhase aPhase) {
  18   // Adding a ClearOnShutdown for a "past" phase is an error.
  19   if (PastShutdownPhase(aPhase)) {
  20     MOZ_ASSERT(false, "ClearOnShutdown for phase that already was cleared");
  21     aObserver->Shutdown();
  22     delete aObserver;
  23     return;
  24   }
  25
  26   if (!(sShutdownObservers[static_cast<size_t>(aPhase)])) {
  27     sShutdownObservers[static_cast<size_t>(aPhase)] = new ShutdownList();
  28   }
  29   sShutdownObservers[static_cast<size_t>(aPhase)]->insertBack(aObserver);
  30 }
  31
  32 }  // namespace ClearOnShutdown_Internal
  33
  34 // Called by AdvanceShutdownPhase each time we switch a phase. Will null out
  35 // pointers added by ClearOnShutdown for all phases up to and including aPhase.
  36 void KillClearOnShutdown(ShutdownPhase aPhase) {
  37   using namespace ClearOnShutdown_Internal;
  38
  39   MOZ_ASSERT(NS_IsMainThread());
  40   // Shutdown only goes one direction...
  41   MOZ_ASSERT(!PastShutdownPhase(aPhase));
  42
  43   // Set the phase before notifying observers to make sure that they can't run
  44   // any code which isn't allowed to run after the start of this phase.
  45   sCurrentClearOnShutdownPhase = aPhase;
  46
  47   // It's impossible to add an entry for a "past" phase; this is blocked in
  48   // ClearOnShutdown, but clear them out anyways in case there are phases
  49   // that weren't passed to KillClearOnShutdown.
  50   for (size_t phase = static_cast<size_t>(ShutdownPhase::First);
  51        phase <= static_cast<size_t>(aPhase); phase++) {
  52     if (sShutdownObservers[static_cast<size_t>(phase)]) {
  53       while (ShutdownObserver* observer =
  54                  sShutdownObservers[static_cast<size_t>(phase)]->popLast()) {
  55         observer->Shutdown();
  56         delete observer;
  57       }
  58       sShutdownObservers[static_cast<size_t>(phase)] = nullptr;
  59     }
  60   }
  61 }
  62
  63 }  // namespace mozilla