content/browser/geolocation/wifi_data_provider.cc

   1 // Copyright 2013 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 "content/browser/geolocation/wifi_data_provider.h"
   6
   7 namespace content {
   8
   9 // static
  10 WifiDataProvider* WifiDataProvider::instance_ = NULL;
  11
  12 // static
  13 WifiDataProvider::ImplFactoryFunction WifiDataProvider::factory_function_ =
  14     DefaultFactoryFunction;
  15
  16 // static
  17 void WifiDataProvider::SetFactory(ImplFactoryFunction factory_function_in) {
  18   factory_function_ = factory_function_in;
  19 }
  20
  21 // static
  22 void WifiDataProvider::ResetFactory() {
  23   factory_function_ = DefaultFactoryFunction;
  24 }
  25
  26 // static
  27 WifiDataProvider* WifiDataProvider::Register(WifiDataUpdateCallback* callback) {
  28   bool need_to_start_data_provider = false;
  29   if (!instance_) {
  30     instance_ = new WifiDataProvider();
  31     need_to_start_data_provider = true;
  32   }
  33   DCHECK(instance_);
  34   instance_->AddCallback(callback);
  35   // Start the provider after adding the callback, to avoid any race in
  36   // it running early.
  37   if (need_to_start_data_provider)
  38     instance_->StartDataProvider();
  39   return instance_;
  40 }
  41
  42 // static
  43 bool WifiDataProvider::Unregister(WifiDataUpdateCallback* callback) {
  44   DCHECK(instance_);
  45   DCHECK(instance_->has_callbacks());
  46   if (!instance_->RemoveCallback(callback)) {
  47     return false;
  48   }
  49   if (!instance_->has_callbacks()) {
  50     // Must stop the data provider (and any implementation threads) before
  51     // destroying to avoid any race conditions in access to the provider in
  52     // the destructor chain.
  53     instance_->StopDataProvider();
  54     delete instance_;
  55     instance_ = NULL;
  56   }
  57   return true;
  58 }
  59
  60 WifiDataProviderImplBase::WifiDataProviderImplBase()
  61     : container_(NULL),
  62       client_loop_(base::MessageLoop::current()) {
  63   DCHECK(client_loop_);
  64 }
  65
  66 WifiDataProviderImplBase::~WifiDataProviderImplBase() {
  67 }
  68
  69 void WifiDataProviderImplBase::SetContainer(WifiDataProvider* container) {
  70   container_ = container;
  71 }
  72
  73 void WifiDataProviderImplBase::AddCallback(WifiDataUpdateCallback* callback) {
  74   callbacks_.insert(callback);
  75 }
  76
  77 bool WifiDataProviderImplBase::RemoveCallback(
  78     WifiDataUpdateCallback* callback) {
  79   return callbacks_.erase(callback) == 1;
  80 }
  81
  82 bool WifiDataProviderImplBase::has_callbacks() const {
  83   return !callbacks_.empty();
  84 }
  85
  86 void WifiDataProviderImplBase::RunCallbacks() {
  87   client_loop_->PostTask(FROM_HERE, base::Bind(
  88       &WifiDataProviderImplBase::DoRunCallbacks,
  89       this));
  90 }
  91
  92 bool WifiDataProviderImplBase::CalledOnClientThread() const {
  93   return base::MessageLoop::current() == this->client_loop_;
  94 }
  95
  96 base::MessageLoop* WifiDataProviderImplBase::client_loop() const {
  97   return client_loop_;
  98 }
  99
 100 void WifiDataProviderImplBase::DoRunCallbacks() {
 101   // It's possible that all the callbacks (and the container) went away
 102   // whilst this task was pending. This is fine; the loop will be a no-op.
 103   CallbackSet::const_iterator iter = callbacks_.begin();
 104   while (iter != callbacks_.end()) {
 105     WifiDataUpdateCallback* callback = *iter;
 106     ++iter;  // Advance iter before running, in case callback unregisters.
 107     callback->Run(container_);
 108   }
 109 }
 110
 111 WifiDataProvider::WifiDataProvider() {
 112   DCHECK(factory_function_);
 113   impl_ = (*factory_function_)();
 114   DCHECK(impl_.get());
 115   impl_->SetContainer(this);
 116 }
 117
 118 WifiDataProvider::~WifiDataProvider() {
 119   DCHECK(impl_.get());
 120   impl_->SetContainer(NULL);
 121 }
 122
 123 bool WifiDataProvider::GetData(WifiData* data) {
 124   return impl_->GetData(data);
 125 }
 126
 127 void WifiDataProvider::AddCallback(WifiDataUpdateCallback* callback) {
 128   impl_->AddCallback(callback);
 129 }
 130
 131 bool WifiDataProvider::RemoveCallback(WifiDataUpdateCallback* callback) {
 132   return impl_->RemoveCallback(callback);
 133 }
 134
 135 bool WifiDataProvider::has_callbacks() const {
 136   return impl_->has_callbacks();
 137 }
 138
 139 void WifiDataProvider::StartDataProvider() {
 140   impl_->StartDataProvider();
 141 }
 142
 143 void WifiDataProvider::StopDataProvider() {
 144   impl_->StopDataProvider();
 145 }
 146
 147 }  // namespace content