bluetooth: Change GetInquiryTxPower and GetInquiryRSSI to return optional.

device/bluetooth/bluez/bluetooth_device_bluez.cc

 // Copyright 2013 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 "device/bluetooth/bluez/bluetooth_device_bluez.h"
 
 #include <stdio.h>
 
+#include <algorithm>
 #include <memory>
 #include <utility>
 
 #include "base/bind.h"
 #include "base/metrics/histogram.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
 #include "dbus/bus.h"
 #include "device/bluetooth/bluetooth_socket.h"
 #include "device/bluetooth/bluetooth_socket_thread.h"
@@ skipping 61 matching lines @@
   if (vendor_id_source != NULL)
     *vendor_id_source = source_value;
   if (vendor_id != NULL)
     *vendor_id = vendor_value;
   if (product_id != NULL)
     *product_id = product_value;
   if (device_id != NULL)
     *device_id = device_value;
 }
 
+int8_t ClampPower(int16_t power) {
+  if (power < INT8_MIN) {
+    return INT8_MIN;
+  }
+  if (power > INT8_MAX) {
+    return INT8_MAX;
+  }
+  return static_cast<int8_t>(power);
+}
+
 void RecordPairingResult(BluetoothDevice::ConnectErrorCode error_code) {
   UMAPairingResult pairing_result;
   switch (error_code) {
     case BluetoothDevice::ERROR_INPROGRESS:
       pairing_result = UMA_PAIRING_RESULT_INPROGRESS;
       break;
     case BluetoothDevice::ERROR_FAILED:
       pairing_result = UMA_PAIRING_RESULT_FAILED;
       break;
     case BluetoothDevice::ERROR_AUTH_FAILED:
@@ skipping 246 matching lines @@
   const std::vector<std::string>& dbus_uuids = properties->uuids.value();
   for (std::vector<std::string>::const_iterator iter = dbus_uuids.begin();
        iter != dbus_uuids.end(); ++iter) {
     device::BluetoothUUID uuid(*iter);
     DCHECK(uuid.IsValid());
     uuids.push_back(uuid);
   }
   return uuids;
 }
 
-int16_t BluetoothDeviceBlueZ::GetInquiryRSSI() const {
+base::Optional<int8_t> BluetoothDeviceBlueZ::GetInquiryRSSI() const {
   bluez::BluetoothDeviceClient::Properties* properties =
       bluez::BluezDBusManager::Get()->GetBluetoothDeviceClient()->GetProperties(
           object_path_);
   DCHECK(properties);
 
   if (!properties->rssi.is_valid())
-    return kUnknownPower;
+    return base::nullopt;
 
-  return properties->rssi.value();
+  // BlueZ uses int16_t because there is no int8_t for DBus, so we should never
+  // get an int16_t that cannot be represented by an int8_t. But just in case
+  // clamp the value.
+  return ClampPower(properties->rssi.value());
 }
 
-int16_t BluetoothDeviceBlueZ::GetInquiryTxPower() const {
+base::Optional<int8_t> BluetoothDeviceBlueZ::GetInquiryTxPower() const {
   bluez::BluetoothDeviceClient::Properties* properties =
       bluez::BluezDBusManager::Get()->GetBluetoothDeviceClient()->GetProperties(
           object_path_);
   DCHECK(properties);
 
   if (!properties->tx_power.is_valid())
-    return kUnknownPower;
+    return base::nullopt;
 
-  return properties->tx_power.value();
+  // BlueZ uses int16_t because there is no int8_t for DBus, so we should never
+  // get an int16_t that cannot be represented by an int8_t. But just in case
+  // clamp the value.
+  return ClampPower(properties->tx_power.value());
 }
 
 bool BluetoothDeviceBlueZ::ExpectingPinCode() const {
   return pairing_.get() && pairing_->ExpectingPinCode();
 }
 
 bool BluetoothDeviceBlueZ::ExpectingPasskey() const {
   return pairing_.get() && pairing_->ExpectingPasskey();
 }
 
@@ skipping 485 matching lines @@
 void BluetoothDeviceBlueZ::OnForgetError(const ErrorCallback& error_callback,
                                          const std::string& error_name,
                                          const std::string& error_message) {
   LOG(WARNING) << object_path_.value()
                << ": Failed to remove device: " << error_name << ": "
                << error_message;
   error_callback.Run();
 }
 
 }  // namespace bluez