chrome.bluetooth API improvements.

device/bluetooth/bluetooth_adapter_factory.cc

Index: device/bluetooth/bluetooth_adapter_factory.cc
diff --git a/device/bluetooth/bluetooth_adapter_factory.cc b/device/bluetooth/bluetooth_adapter_factory.cc
index c15d26a514b3082a1fe5c89649e88d70dbfedeba..b9889c6742934e96a55f10db940832f1984d0355 100644
--- a/device/bluetooth/bluetooth_adapter_factory.cc
+++ b/device/bluetooth/bluetooth_adapter_factory.cc
@@ -26,6 +26,9 @@ namespace {
 using device::BluetoothAdapter;
 using device::BluetoothAdapterFactory;
 
+base::LazyInstance<BluetoothAdapterFactory> adapter_factory =
+    LAZY_INSTANCE_INITIALIZER;
+
 // Shared default adapter instance, we don't want to keep this class around
 // if nobody is using it so use a WeakPtr and create the object when needed;
 // since Google C++ Style (and clang's static analyzer) forbids us having
@@ -61,6 +64,12 @@ void RunAdapterCallbacks() {
 namespace device {
 
 // static
+void BluetoothAdapterFactory::SetAdapterInitializer(
+    AdapterInitializer initializer) {
+  adapter_factory.Get().adapter_initializer_ = initializer;

[keybuk, 2014/03/20 01:21:56]

This doesn't run the initializer if the adapter is already initialized by
another part of the code

[rpaquay, 2014/03/20 18:21:11]

The issue is that the "device" layer needs initialization from an upper layer
("extensions::BluetoothAPI"). This is currently specific to Windows only, where
the upper layer needs to pass the FILE thread and net::log instances to the
Windows Adapater implementation.

Other than requiring the upper layer to do guarantee setting the initializer
before the adapter is used, I don't know of any other option.

I am not a fan of this approach, but couldn't think of a better way. Suggestions
are welcome on how to better implement this pattern.

[keybuk, 2014/03/20 18:38:40]

Sure, but the extensions::BluetoothAPI may not be the first component of Chrome
to be initialized... in the case where using the Aura shell, wouldn't be the
Aura UI be initialized first?

The Aura UI holds a reference to the BluetoothAdapter

So when the BluetoothAPI class goes to get it, the existing adapter will just be
returned, and the initializer function won't be called.

[rpaquay, 2014/03/25 20:06:10]

These are all good points. After thinking about this a little bit more, I
decided that it would be best to avoid any additional platform specific global
initialization. To enable that, I had to rethink the threading model a little
bit more, and I think I came up with a simplified model for Windows, very
similar to the way ChromeOS currently works: Consumers always talks to the API
via the UI thread and the platform specific implementation use a dedicated
thread for socket IO. This makes the latest patchset quite big, but I think it
is for the best.

+}
+
+// static
 bool BluetoothAdapterFactory::IsBluetoothAdapterAvailable() {
 #if defined(OS_CHROMEOS)
   return true;
@@ -68,8 +77,9 @@ bool BluetoothAdapterFactory::IsBluetoothAdapterAvailable() {
   return true;
 #elif defined(OS_MACOSX)
   return base::mac::IsOSLionOrLater();
-#endif
+#else
   return false;
+#endif
 }
 
 // static
@@ -78,15 +88,18 @@ void BluetoothAdapterFactory::GetAdapter(const AdapterCallback& callback) {
 #if defined(OS_CHROMEOS)
     chromeos::BluetoothAdapterChromeOS* new_adapter =
         new chromeos::BluetoothAdapterChromeOS();
+    adapter_factory.Get().adapter_initializer_.Run(new_adapter);
     default_adapter.Get() = new_adapter->weak_ptr_factory_.GetWeakPtr();
 #elif defined(OS_WIN)
     BluetoothAdapterWin* new_adapter = new BluetoothAdapterWin(
         base::Bind(&RunAdapterCallbacks));
     new_adapter->Init();
+    adapter_factory.Get().adapter_initializer_.Run(new_adapter);

[keybuk, 2014/03/20 01:21:56]

the adapter might not be initialized yet?

[rpaquay, 2014/03/20 18:21:11]

The initialization callback is intended to be part of the Adapter instance class
initialization, not part of the "the physical Bluetooth Adapter" is ready.

[keybuk, 2014/03/20 18:38:40]

Ack

     default_adapter.Get() = new_adapter->weak_ptr_factory_.GetWeakPtr();
 #elif defined(OS_MACOSX)
     BluetoothAdapterMac* new_adapter = new BluetoothAdapterMac();
     new_adapter->Init();
+    adapter_factory.Get().adapter_initializer_.Run(new_adapter);

[keybuk, 2014/03/20 01:21:56]

adapter might not be initialized yet

[rpaquay, 2014/03/20 18:21:11]

See Above.

     default_adapter.Get() = new_adapter->weak_ptr_factory_.GetWeakPtr();
 #endif
   }