image/src/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 "nsAutoPtr.h"
  10 #include "nsIObserver.h"
  11 #include "nsIObserverService.h"
  12
  13 namespace mozilla {
  14 namespace image {
  15
  16 class ShutdownTrackerImpl;
  17
  18 ///////////////////////////////////////////////////////////////////////////////
  19 // Static Data
  20 ///////////////////////////////////////////////////////////////////////////////
  21
  22 // Whether we've observed shutdown starting yet.
  23 static bool sShutdownHasStarted = false;
  24
  25
  26 ///////////////////////////////////////////////////////////////////////////////
  27 // Implementation
  28 ///////////////////////////////////////////////////////////////////////////////
  29
  30 struct ShutdownObserver : public nsIObserver
  31 {
  32   NS_DECL_ISUPPORTS
  33
  34   NS_IMETHOD Observe(nsISupports*, const char* aTopic, const char16_t*) override
  35   {
  36     if (strcmp(aTopic, "xpcom-shutdown") != 0) {
  37       return NS_OK;
  38     }
  39
  40     nsCOMPtr<nsIObserverService> os = services::GetObserverService();
  41     if (os) {
  42       os->RemoveObserver(this, "xpcom-shutdown");
  43     }
  44
  45     sShutdownHasStarted = true;
  46     return NS_OK;
  47   }
  48
  49 private:
  50   virtual ~ShutdownObserver() { }
  51 };
  52
  53 NS_IMPL_ISUPPORTS(ShutdownObserver, nsIObserver)
  54
  55
  56 ///////////////////////////////////////////////////////////////////////////////
  57 // Public API
  58 ///////////////////////////////////////////////////////////////////////////////
  59
  60 /* static */ void
  61 ShutdownTracker::Initialize()
  62 {
  63   nsCOMPtr<nsIObserverService> os = services::GetObserverService();
  64   if (os) {
  65     os->AddObserver(new ShutdownObserver, "xpcom-shutdown", false);
  66   }
  67 }
  68
  69 /* static */ bool
  70 ShutdownTracker::ShutdownHasStarted()
  71 {
  72   return sShutdownHasStarted;
  73 }
  74
  75 } // namespace image
  76 } // namespace mozilla