bluetooth: Implement RSSI and Tx Power on macOS and Android

device/bluetooth/bluetooth_adapter_android.cc

Index: device/bluetooth/bluetooth_adapter_android.cc
diff --git a/device/bluetooth/bluetooth_adapter_android.cc b/device/bluetooth/bluetooth_adapter_android.cc
index 5905d49d41f19a3d63cced7de8fcb6bb577a7636..e36a81a76d1912f3ce637854ae7c2aa65d55bf58 100644
--- a/device/bluetooth/bluetooth_adapter_android.cc
+++ b/device/bluetooth/bluetooth_adapter_android.cc
@@ -184,8 +184,9 @@ void BluetoothAdapterAndroid::CreateOrUpdateDeviceOnScan(
     const JavaParamRef<jstring>& address,
     const JavaParamRef<jobject>&
         bluetooth_device_wrapper,  // Java Type: bluetoothDeviceWrapper
-    const JavaParamRef<jobjectArray>&
-        advertised_uuids) {  // Java Type: String[]
+    int32_t rssi,
+    const JavaParamRef<jobjectArray>& advertised_uuids,  // Java Type: String[]
+    int32_t tx_power) {
   std::string device_address = ConvertJavaStringToUTF8(env, address);
   DevicesMap::const_iterator iter = devices_.find(device_address);
 
@@ -207,14 +208,21 @@ void BluetoothAdapterAndroid::CreateOrUpdateDeviceOnScan(
   std::vector<std::string> advertised_uuids_strings;
   AppendJavaStringArrayToStringVector(env, advertised_uuids,
                                       &advertised_uuids_strings);
-
   BluetoothDevice::UUIDList advertised_bluetooth_uuids;
   for (std::string& uuid : advertised_uuids_strings) {
     advertised_bluetooth_uuids.push_back(BluetoothUUID(std::move(uuid)));
   }
 
-  device_android->UpdateAdvertisementData(std::move(advertised_bluetooth_uuids),
-                                          {} /* service_data */);
+  // Android uses INT32_MIN to indicate no Advertised Tx Power.

[Jeffrey Yasskin, 2016/08/24 04:32:02]

Link to
https://developer.android.com/reference/android/bluetooth/le/ScanRecord.html#...
in the comment, I think.

[ortuno, 2016/08/24 21:29:09]

Done.

+  base::Optional<int8_t> clamped_tx_power =
+      tx_power == INT32_MIN
+          ? base::nullopt
+          : base::make_optional<int8_t>(BluetoothDevice::ClampPower(tx_power));
+
+  device_android->UpdateAdvertisementData(
+      BluetoothDevice::ClampPower(rssi), std::move(advertised_bluetooth_uuids),
+      {} /* service_data */,
+      clamped_tx_power ? &clamped_tx_power.value() : nullptr);

[Jeffrey Yasskin, 2016/08/24 04:32:02]

Should UpdateAdvertisementData take an optional, if you're unwrapping on in the
call?

[ortuno, 2016/08/24 21:29:09]

Hmmm I thought about passing an optional but base::Optional's documentation
recommends not to use it as a function parameter. WDYT?

https://chromium.googlesource.com/chromium/src/+/master/docs/optional.md#When...

[Jeffrey Yasskin, 2016/08/24 22:32:07]

As discussed over IM, it probably makes sense to store the clamped power in a
local variable, and put "tx_power == INT32_MIN ? nullptr : &clamped_tx_power"
here, instead of building an Optional. You could also add GetPtr(Optional) to
optional.h if you're feeling yak-shavy today.

[ortuno, 2016/08/25 16:42:34]

Done.
Not on a branch day :) Maybe once I move if it keeps coming up.

 
   if (is_new_device) {
     devices_.add(device_address, std::move(device_android_owner));