Lazy-creates BluetoothAdapter in ExtensionBluetoothEventRouter (EBEE).

chrome/browser/extensions/bluetooth_event_router.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/extensions/bluetooth_event_router.h"
 
 #include <map>
+#include <string>
 
 #include "base/json/json_writer.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_vector.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/extensions/api/bluetooth/bluetooth_api_utils.h"
 #include "chrome/browser/extensions/event_names.h"
 #include "chrome/browser/extensions/event_router.h"
 #include "chrome/browser/extensions/extension_system.h"
 #include "chrome/common/extensions/api/bluetooth.h"
 #include "device/bluetooth/bluetooth_adapter.h"
 #include "device/bluetooth/bluetooth_adapter_factory.h"
 #include "device/bluetooth/bluetooth_device.h"
 #include "device/bluetooth/bluetooth_socket.h"
 
 namespace extensions {
 
 ExtensionBluetoothEventRouter::ExtensionBluetoothEventRouter(Profile* profile)
     : send_discovery_events_(false),
       responsible_for_discovery_(false),
       profile_(profile),
-      adapter_(device::BluetoothAdapterFactory::DefaultAdapter()),
+      adapter_(NULL),
+      num_event_listeners_(0),
       next_socket_id_(1) {
   DCHECK(profile_);
-  if (adapter_.get())
-    adapter_->AddObserver(this);
 }
 
 ExtensionBluetoothEventRouter::~ExtensionBluetoothEventRouter() {
-  if (adapter_.get())
-    adapter_->RemoveObserver(this);
+  MaybeReleaseAdapter();
 
   socket_map_.clear();
 }
 
+scoped_refptr<const device::BluetoothAdapter>
+ExtensionBluetoothEventRouter::adapter() {
+  return GetMutableAdapter();
+}
+
+scoped_refptr<device::BluetoothAdapter>
+ExtensionBluetoothEventRouter::GetMutableAdapter() {
+  if (adapter_)
+    return adapter_;
+
+  return device::BluetoothAdapterFactory::DefaultAdapter();
+}
+
+void ExtensionBluetoothEventRouter::InitializeAdapterIfNeeded() {
+  if (!adapter_) {
+    adapter_ = GetMutableAdapter();
+    adapter_->AddObserver(this);
+  }
+}
+
+void ExtensionBluetoothEventRouter::MaybeReleaseAdapter() {
+  if (adapter_) {
+    adapter_->RemoveObserver(this);
+    adapter_ = NULL;
+  }
+}
+
 int ExtensionBluetoothEventRouter::RegisterSocket(
     scoped_refptr<device::BluetoothSocket> socket) {
   // If there is a socket registered with the same fd, just return it's id
   for (SocketMap::const_iterator i = socket_map_.begin();
       i != socket_map_.end(); ++i) {
     if (i->second->fd() == socket->fd()) {
       return i->first;
     }
   }
   int return_id = next_socket_id_++;
   socket_map_[return_id] = socket;
+  InitializeAdapterIfNeeded();
+
   return return_id;
 }
 
 bool ExtensionBluetoothEventRouter::ReleaseSocket(int id) {
   SocketMap::iterator socket_entry = socket_map_.find(id);
   if (socket_entry == socket_map_.end())
     return false;
   socket_map_.erase(socket_entry);
+  if (!IsAdapterNeeded())
+    MaybeReleaseAdapter();
+
   return true;
 }
 
 scoped_refptr<device::BluetoothSocket>
 ExtensionBluetoothEventRouter::GetSocket(int id) {
   SocketMap::iterator socket_entry = socket_map_.find(id);
   if (socket_entry == socket_map_.end())
     return NULL;
   return socket_entry->second;
 }
 
+// static
+bool ExtensionBluetoothEventRouter::IsBluetoothEvent(
+    const std::string& event_name) {
+  return
+      event_name == extensions::event_names::kBluetoothOnAvailabilityChanged ||
+      event_name == extensions::event_names::kBluetoothOnDiscoveringChanged ||
+      event_name == extensions::event_names::kBluetoothOnPowerChanged;
+}
+
+bool ExtensionBluetoothEventRouter::IsAdapterNeeded() const {
+  return num_event_listeners_ > 0 || socket_map_.size() > 0;
+}
+
+void ExtensionBluetoothEventRouter::OnEventListenerAdded(
+    const std::string& event_name) {
+  if (IsBluetoothEvent(event_name)) {
+    num_event_listeners_++;
+    InitializeAdapterIfNeeded();
+  }
+}
+
+void ExtensionBluetoothEventRouter::OnEventListenerRemoved(
+    const std::string& event_name) {
+  if (IsBluetoothEvent(event_name)) {
+    num_event_listeners_--;
+    DCHECK(num_event_listeners_ >= 0);
+    if (!IsAdapterNeeded())
+      MaybeReleaseAdapter();
+  }
+}
+
 void ExtensionBluetoothEventRouter::SetResponsibleForDiscovery(
     bool responsible) {
   responsible_for_discovery_ = responsible;
 }
 
 bool ExtensionBluetoothEventRouter::IsResponsibleForDiscovery() const {
   return responsible_for_discovery_;
 }
 
 void ExtensionBluetoothEventRouter::SetSendDiscoveryEvents(bool should_send) {
@@ skipping 13 matching lines @@
 void ExtensionBluetoothEventRouter::DispatchDeviceEvent(
     const char* event_name, const extensions::api::bluetooth::Device& device) {
   scoped_ptr<ListValue> args(new ListValue());
   args->Append(device.ToValue().release());
   extensions::ExtensionSystem::Get(profile_)->event_router()->
       DispatchEventToRenderers(event_name, args.Pass(), NULL, GURL());
 }
 
 void ExtensionBluetoothEventRouter::AdapterPresentChanged(
     device::BluetoothAdapter* adapter, bool present) {
-  if (adapter != adapter_.get()) {
+  if (adapter != adapter_) {
     DVLOG(1) << "Ignoring event for adapter " << adapter->address();
     return;
   }
 
   DispatchBooleanValueEvent(
       extensions::event_names::kBluetoothOnAvailabilityChanged,
       present);
 }
 
 void ExtensionBluetoothEventRouter::AdapterPoweredChanged(
     device::BluetoothAdapter* adapter, bool has_power) {
-  if (adapter != adapter_.get()) {
+  if (adapter != adapter_) {
     DVLOG(1) << "Ignoring event for adapter " << adapter->address();
     return;
   }
 
   DispatchBooleanValueEvent(
       extensions::event_names::kBluetoothOnPowerChanged,
       has_power);
 }
 
 void ExtensionBluetoothEventRouter::AdapterDiscoveringChanged(
     device::BluetoothAdapter* adapter, bool discovering) {
-  if (adapter != adapter_.get()) {
+  if (adapter != adapter_) {
     DVLOG(1) << "Ignoring event for adapter " << adapter->address();
     return;
   }
 
   if (!discovering) {
     send_discovery_events_ = false;
     responsible_for_discovery_ = false;
     discovered_devices_.clear();
   }
 
   DispatchBooleanValueEvent(
       extensions::event_names::kBluetoothOnDiscoveringChanged,
       discovering);
 }
 
 void ExtensionBluetoothEventRouter::DeviceAdded(
     device::BluetoothAdapter* adapter,
     device::BluetoothDevice* device) {
-  if (adapter != adapter_.get()) {
+  if (adapter != adapter_) {
     DVLOG(1) << "Ignoring event for adapter " << adapter->address();
     return;
   }
 
   extensions::api::bluetooth::Device* extension_device =
       new extensions::api::bluetooth::Device();
   extensions::api::bluetooth::BluetoothDeviceToApiDevice(
       *device, extension_device);
   discovered_devices_.push_back(extension_device);
 
   if (!send_discovery_events_)
     return;
 
   DispatchDeviceEvent(extensions::event_names::kBluetoothOnDeviceDiscovered,
                       *extension_device);
 }
 
 void ExtensionBluetoothEventRouter::DispatchBooleanValueEvent(
     const char* event_name, bool value) {
   scoped_ptr<ListValue> args(new ListValue());
   args->Append(Value::CreateBooleanValue(value));
   extensions::ExtensionSystem::Get(profile_)->event_router()->
       DispatchEventToRenderers(event_name, args.Pass(), NULL, GURL());
 }
 
 }  // namespace extensions