mac: Add metrics to record Bluetooth availability and capabilities.

chrome/browser/mac/bluetooth_utility.mm

+// Copyright 2014 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/mac/bluetooth_utility.h"
+
+#import <Foundation/Foundation.h>
+#include <IOKit/IOKitLib.h>
+
+#include "base/mac/foundation_util.h"
+#include "base/mac/mac_util.h"
+#include "base/mac/scoped_ioobject.h"
+#include "base/mac/sdk_forward_declarations.h"
+
+namespace bluetooth_utility {
+
+BluetoothAvailability GetBluetoothAvailability() {
+  base::ScopedCFTypeRef<CFMutableDictionaryRef> matching_dict(
+      IOServiceMatching("IOBluetoothHCIController"));
+  if (!matching_dict)
+    return BLUETOOTH_AVAILABILITY_ERROR;
+
+  // IOServiceGetMatchingServices takes ownership of matching_dict.
+  io_iterator_t iter;
+  int kr = IOServiceGetMatchingServices(
+      kIOMasterPortDefault, matching_dict.release(), &iter);
+  if (kr != KERN_SUCCESS)
+    return BLUETOOTH_NOT_AVAILABLE;
+  base::mac::ScopedIOObject<io_iterator_t> scoped_iter(iter);
+
+  int bluetooth_available = false;
+  int le_unknown = false;
+  base::mac::ScopedIOObject<io_service_t> device;
+  while (device.reset(IOIteratorNext(scoped_iter.get())), device) {
+    bluetooth_available = true;
+
+    CFMutableDictionaryRef dict;
+    kr = IORegistryEntryCreateCFProperties(
+        device, &dict, kCFAllocatorDefault, kNilOptions);
+    if (kr != KERN_SUCCESS)
+      continue;
+    base::ScopedCFTypeRef<CFMutableDictionaryRef> scoped_dict(dict);
+
+    NSDictionary* objc_dict = base::mac::CFToNSCast(scoped_dict.get());
+    NSNumber* lmp_version =
+        base::mac::ObjCCast<NSNumber>([objc_dict objectForKey:@"LMPVersion"]);
+    if (!lmp_version)
+      continue;
+
+    // The LMP version is too low to support Bluetooth LE.
+    if ([lmp_version intValue] < 6)
+      continue;
+
+    // Check the supported features registry entry for Bluetooth LE
+    // availability. The relevant bit has a different meaning on OSX 10.6, and
+    // could change again in the future.
+    if (base::mac::IsOSSnowLeopard()) {
+      le_unknown = true;

[Mark Mentovai, 2014/07/11 22:26:29]

You can return BLUETOOTH_AVAILABLE_LE_UNKNOWN right here, and get rid of the
le_unknown variable. The OS isn’t going to change from 10.6 if you make another
pass through the loop.

[erikchen, 2014/07/11 22:39:59]

Done.

+      continue;
+    }
+
+    NSData* data = base::mac::ObjCCast<NSData>(
+        [objc_dict objectForKey:@"HCISupportedFeatures"]);
+
+    NSUInteger supported_features_index = 4;
+    NSUInteger length = [data length];
+    if (length < supported_features_index + 1)
+      continue;
+
+    // The bytes are indexed in reverse order.
+    NSUInteger index = length - supported_features_index - 1;
+
+    const unsigned char* bytes =
+        static_cast<const unsigned char*>([data bytes]);
+    const unsigned char byte = bytes[index];
+    bool le_supported = byte & kBluetoothFeatureLESupportedController;
+    if (le_supported)
+      return BLUETOOTH_AVAILABLE_WITH_LE;
+  }
+
+  if (le_unknown)
+    return BLUETOOTH_AVAILABLE_LE_UNKNOWN;
+  return bluetooth_available ? BLUETOOTH_AVAILABLE_WITHOUT_LE
+                             : BLUETOOTH_AVAILABILITY_ERROR;
+}
+
+}  // namespace bluetooth_utility