mojo/application/public/cpp/lib/app_lifetime_helper.cc

   1 // Copyright 2015 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "mojo/application/public/cpp/app_lifetime_helper.h"
   6
   7 #include "base/bind.h"
   8 #include "base/message_loop/message_loop.h"
   9 #include "mojo/application/public/cpp/application_impl.h"
  10
  11 namespace mojo {
  12
  13 AppRefCount::AppRefCount(
  14     AppLifetimeHelper* app_lifetime_helper,
  15     scoped_refptr<base::SingleThreadTaskRunner> app_task_runner)
  16     : app_lifetime_helper_(app_lifetime_helper),
  17       app_task_runner_(app_task_runner) {
  18 }
  19
  20 AppRefCount::~AppRefCount() {
  21 #ifndef NDEBUG
  22   // Ensure that this object is used on only one thread at a time, or else there
  23   // could be races where the object is being reset on one thread and cloned on
  24   // another.
  25   if (clone_task_runner_) {
  26     DCHECK(clone_task_runner_->BelongsToCurrentThread());
  27   }
  28 #endif
  29
  30   if (app_task_runner_->BelongsToCurrentThread()) {
  31     app_lifetime_helper_->Release();
  32     return;
  33   }
  34
  35   app_task_runner_->PostTask(
  36       FROM_HERE,
  37       base::Bind(&AppLifetimeHelper::Release,
  38                  base::Unretained(app_lifetime_helper_)));
  39 }
  40
  41 scoped_ptr<AppRefCount> AppRefCount::Clone() {
  42   if (app_task_runner_->BelongsToCurrentThread()) {
  43     app_lifetime_helper_->AddRef();
  44   } else {
  45     app_task_runner_->PostTask(
  46         FROM_HERE,
  47         base::Bind(&AppLifetimeHelper::AddRef,
  48                    base::Unretained(app_lifetime_helper_)));
  49   }
  50
  51 #ifndef NDEBUG
  52   // Ensure that this object is used on only one thread at a time, or else there
  53   // could be races where the object is being reset on one thread and cloned on
  54   // another.
  55   if (clone_task_runner_) {
  56     DCHECK(clone_task_runner_->BelongsToCurrentThread());
  57   } else {
  58     clone_task_runner_ = base::MessageLoop::current()->task_runner();
  59   }
  60 #endif
  61
  62   return make_scoped_ptr(new AppRefCount(
  63       app_lifetime_helper_, app_task_runner_));
  64 }
  65
  66 AppLifetimeHelper::AppLifetimeHelper(ApplicationImpl* app)
  67     : app_(app), ref_count_(0) {
  68 }
  69
  70 AppLifetimeHelper::~AppLifetimeHelper() {
  71 }
  72
  73 scoped_ptr<AppRefCount> AppLifetimeHelper::CreateAppRefCount() {
  74   AddRef();
  75   return make_scoped_ptr(new AppRefCount(
  76       this, base::MessageLoop::current()->task_runner()));
  77 }
  78
  79 void AppLifetimeHelper::AddRef() {
  80   ref_count_++;
  81 }
  82
  83 void AppLifetimeHelper::Release() {
  84   if (!--ref_count_) {
  85     if (app_)
  86       app_->Quit();
  87   }
  88 }
  89
  90 void AppLifetimeHelper::OnQuit() {
  91   app_ = nullptr;
  92 }
  93
  94 }  // namespace mojo