image/ShutdownTracker.cpp

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #include "ShutdownTracker.h"
   7
   8 #include "mozilla/Services.h"
   9 #include "nsIObserver.h"
  10 #include "nsIObserverService.h"
  11
  12 namespace mozilla {
  13 namespace image {
  14
  15 class ShutdownTrackerImpl;
  16
  17 ///////////////////////////////////////////////////////////////////////////////
  18 // Static Data
  19 ///////////////////////////////////////////////////////////////////////////////
  20
  21 // Whether we've observed shutdown starting yet.
  22 static bool sShutdownHasStarted = false;
  23
  24
  25 ///////////////////////////////////////////////////////////////////////////////
  26 // Implementation
  27 ///////////////////////////////////////////////////////////////////////////////
  28
  29 struct ShutdownObserver : public nsIObserver
  30 {
  31   NS_DECL_ISUPPORTS
  32
  33   NS_IMETHOD Observe(nsISupports*, const char* aTopic, const char16_t*) override
  34   {
  35     if (strcmp(aTopic, "xpcom-shutdown") != 0) {
  36       return NS_OK;
  37     }
  38
  39     nsCOMPtr<nsIObserverService> os = services::GetObserverService();
  40     if (os) {
  41       os->RemoveObserver(this, "xpcom-shutdown");
  42     }
  43
  44     sShutdownHasStarted = true;
  45     return NS_OK;
  46   }
  47
  48 private:
  49   virtual ~ShutdownObserver() { }
  50 };
  51
  52 NS_IMPL_ISUPPORTS(ShutdownObserver, nsIObserver)
  53
  54
  55 ///////////////////////////////////////////////////////////////////////////////
  56 // Public API
  57 ///////////////////////////////////////////////////////////////////////////////
  58
  59 /* static */ void
  60 ShutdownTracker::Initialize()
  61 {
  62   nsCOMPtr<nsIObserverService> os = services::GetObserverService();
  63   if (os) {
  64     os->AddObserver(new ShutdownObserver, "xpcom-shutdown", false);
  65   }
  66 }
  67
  68 /* static */ bool
  69 ShutdownTracker::ShutdownHasStarted()
  70 {
  71   return sShutdownHasStarted;
  72 }
  73
  74 } // namespace image
  75 } // namespace mozilla