Implement Bluetooth server socket support for RFCOMM on Mac.

device/bluetooth/bluetooth_profile_mac.mm

 // 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/bluetooth_profile_mac.h"
 
-#import <IOBluetooth/objc/IOBluetoothDevice.h>
-#import <IOBluetooth/objc/IOBluetoothSDPServiceRecord.h>
-#import <IOBluetooth/objc/IOBluetoothSDPUUID.h>
-
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/logging.h"
+#include "base/mac/scoped_cftyperef.h"
 #include "base/memory/ref_counted.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/sys_string_conversions.h"
 #include "device/bluetooth/bluetooth_adapter_factory.h"
 #include "device/bluetooth/bluetooth_device_mac.h"
 #include "device/bluetooth/bluetooth_socket_mac.h"
 
 // Replicate specific 10.7 SDK declarations for building with prior SDKs.
 #if !defined(MAC_OS_X_VERSION_10_7) || \
     MAC_OS_X_VERSION_MAX_ALLOWED < MAC_OS_X_VERSION_10_7
 
 @interface IOBluetoothDevice (LionSDKDeclarations)
 - (NSString*)addressString;
 @end
 
 #endif  // MAC_OS_X_VERSION_10_7
 
+namespace device {
 namespace {
 
 const char kNoConnectionCallback[] = "Connection callback not set";
 const char kProfileNotFound[] = "Profile not found";
 
+// 0 is a safe way to represent an unregistered service, as implied by the
+// documentation at
+// https://developer.apple.com/library/mac/documentation/devicedrivers/conceptual/bluetooth/BT_Develop_BT_Apps/BT_Develop_BT_Apps.html
+const BluetoothSDPServiceRecordHandle kInvalidServiceRecordHandle = 0;
+
 // Converts |uuid| to a IOBluetoothSDPUUID instance.
 //
 // |uuid| must be in the format of XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX.
 IOBluetoothSDPUUID* GetIOBluetoothSDPUUID(const std::string& uuid) {
   DCHECK(uuid.size() == 36);
   DCHECK(uuid[8] == '-');
   DCHECK(uuid[13] == '-');
   DCHECK(uuid[18] == '-');
   DCHECK(uuid[23] == '-');
   std::string numbers_only = uuid;
   numbers_only.erase(23, 1);
   numbers_only.erase(18, 1);
   numbers_only.erase(13, 1);
   numbers_only.erase(8, 1);
   std::vector<uint8> uuid_bytes_vector;
   base::HexStringToBytes(numbers_only, &uuid_bytes_vector);
   DCHECK(uuid_bytes_vector.size() == 16);
 
-  return [IOBluetoothSDPUUID uuidWithBytes:&uuid_bytes_vector[0]
+  return [IOBluetoothSDPUUID uuidWithBytes:&uuid_bytes_vector.front()
                                     length:uuid_bytes_vector.size()];
 }
 
 void OnConnectSuccessWithAdapter(
     const base::Closure& callback,
-    const device::BluetoothProfileMac::ConnectionCallback& connection_callback,
+    const BluetoothProfileMac::ConnectionCallback& connection_callback,
     const std::string& device_address,
-    scoped_refptr<device::BluetoothSocketMac> socket,
-    scoped_refptr<device::BluetoothAdapter> adapter) {
-  const device::BluetoothDevice* device = adapter->GetDevice(device_address);
+    scoped_refptr<BluetoothSocket> socket,
+    scoped_refptr<BluetoothAdapter> adapter) {
+  const BluetoothDevice* device = adapter->GetDevice(device_address);
   if (device) {
     connection_callback.Run(device, socket);
-    callback.Run();
+    if (!callback.is_null())
+      callback.Run();
   }
 }
 
 void OnConnectSuccess(
     const base::Closure& callback,
-    const device::BluetoothProfileMac::ConnectionCallback& connection_callback,
+    const BluetoothProfileMac::ConnectionCallback& connection_callback,
     const std::string& device_address,
-    scoped_refptr<device::BluetoothSocketMac> socket) {
-  device::BluetoothAdapterFactory::GetAdapter(
+    scoped_refptr<BluetoothSocket> socket) {
+  BluetoothAdapterFactory::GetAdapter(
       base::Bind(&OnConnectSuccessWithAdapter,
                  callback,
                  connection_callback,
                  device_address,
                  socket));
 }
 
+// Converts the given |integer| to a string.
+NSString* IntToNSString(int integer) {
+  return [[NSNumber numberWithInt:integer] stringValue];
+}
+
+// Returns a dictionary containing the Bluetooth service definition
+// corresponding to the provided |uuid| and |options|.
+// TODO(isherman): Support more of the fields defined in |options|.
+NSDictionary* BuildServiceDefinition(const BluetoothUUID& uuid,
+                                     const BluetoothProfile::Options& options) {
+  NSMutableDictionary* service_definition = [NSMutableDictionary dictionary];
+
+  // TODO(isherman): The service's language is currently hardcoded to English.
+  // The language should ideally be specified in the chrome.bluetooth API
+  // instead.
+  const int kEnglishLanguageBase = 100;
+  const int kServiceNameKey =
+      kEnglishLanguageBase + kBluetoothSDPAttributeIdentifierServiceName;
+  NSString* service_name = base::SysUTF8ToNSString(options.name);
+  [service_definition setObject:service_name
+                         forKey:IntToNSString(kServiceNameKey)];
+
+  const int kUUIDsKey = kBluetoothSDPAttributeIdentifierServiceClassIDList;
+  NSArray* uuids = @[GetIOBluetoothSDPUUID(uuid.canonical_value())];
+  [service_definition setObject:uuids forKey:IntToNSString(kUUIDsKey)];
+
+  const int kProtocolDefinitionsKey =
+      kBluetoothSDPAttributeIdentifierProtocolDescriptorList;
+  NSArray* rfcomm_protocol_definition =
+      @[[IOBluetoothSDPUUID uuid16:kBluetoothSDPUUID16RFCOMM],
+        [NSNumber numberWithInt:options.channel]];
+  [service_definition setObject:@[rfcomm_protocol_definition]
+                         forKey:IntToNSString(kProtocolDefinitionsKey)];
+
+  return service_definition;
+}
+
+// Registers a Bluetooth service with the specifieid |uuid| and |options| in the
+// system SDP server. Returns a handle to the registered service, or
+// |kInvalidServcieRecordHandle| if the service could not be registered.
+BluetoothSDPServiceRecordHandle RegisterService(
+    const BluetoothUUID& uuid,
+    const BluetoothProfile::Options& options) {
+  // Attempt to register the service.
+  NSDictionary* service_definition = BuildServiceDefinition(uuid, options);
+  IOBluetoothSDPServiceRecordRef service_record_ref;
+  IOReturn result =
+      IOBluetoothAddServiceDict((CFDictionaryRef)service_definition,
+                                &service_record_ref);
+  if (result != kIOReturnSuccess)
+    return kInvalidServiceRecordHandle;
+  // Transfer ownership to a scoped object, to simplify memory management.
+  base::ScopedCFTypeRef<IOBluetoothSDPServiceRecordRef>
+      scoped_service_record_ref(service_record_ref);
+
+  // Extract the service record handle.
+  BluetoothSDPServiceRecordHandle service_record_handle;
+  IOBluetoothSDPServiceRecord* service_record =
+      [IOBluetoothSDPServiceRecord withSDPServiceRecordRef:service_record_ref];
+  result = [service_record getServiceRecordHandle:&service_record_handle];
+  if (result != kIOReturnSuccess)
+    return kInvalidServiceRecordHandle;
+
+  // Verify that the requested channel id was available. If not, withdraw the
+  // service.

[Ilya Sherman, 2014/04/19 05:11:25]

Is this appropriate, or is the channel provided in options intended to merely be
a hint?

[keybuk, 2014/04/19 07:54:05]

When specified, it should be equivalent to requesting a TCP Port - so this is
appropriate.

When not specified, it should be equivalent to "bind to any free"

[Ilya Sherman, 2014/04/22 00:27:20]

Sounds good.  I've added a TODO for now, as there chrome.bluetooth API doesn't
currently offer a clear way to register an RFCOMM service without specifying a
channel explicitly.

+  BluetoothRFCOMMChannelID rfcomm_channel_id;
+  result = [service_record getRFCOMMChannelID:&rfcomm_channel_id];
+  if (result != kIOReturnSuccess || rfcomm_channel_id != options.channel) {
+    IOBluetoothRemoveServiceWithRecordHandle(service_record_handle);
+    return kInvalidServiceRecordHandle;
+  }
+
+  return service_record_handle;
+}
+
 }  // namespace
+}  // namespace device
+
+// A simple helper class that forwards system notifications to its wrapped
+// |profile_|.
+@interface BluetoothProfileMacHelper : NSObject {
+ @private
+  // The profile that owns |self|.
+  device::BluetoothProfileMac* profile_;  // weak
+
+  // The OS mechanism used to subscribe to and unsubscribe from RFCOMM channel
+  // creation notifications.
+  IOBluetoothUserNotification* rfcommNewChannelNotification_;  // weak
+}
+
+- (id)initWithProfile:(device::BluetoothProfileMac*)profile
+            channelID:(BluetoothRFCOMMChannelID)channelID;
+- (void)rfcommChannelOpened:(IOBluetoothUserNotification*)notification
+                    channel:(IOBluetoothRFCOMMChannel*)rfcommChannel;
+
+@end
+
+@implementation BluetoothProfileMacHelper
+
+- (id)initWithProfile:(device::BluetoothProfileMac*)profile
+            channelID:(BluetoothRFCOMMChannelID)channelID {
+  if ((self = [super init])) {
+    profile_ = profile;
+
+    SEL selector = @selector(rfcommChannelOpened:channel:);
+    const auto kIncomingDirection =
+        kIOBluetoothUserNotificationChannelDirectionIncoming;
+    rfcommNewChannelNotification_ =
+        [IOBluetoothRFCOMMChannel
+          registerForChannelOpenNotifications:self
+                                     selector:selector
+                                withChannelID:channelID
+                                    direction:kIncomingDirection];
+  }
+
+  return self;
+}
+
+- (void)dealloc {
+  [rfcommNewChannelNotification_ unregister];
+  [super dealloc];
+}
+
+- (void)rfcommChannelOpened:(IOBluetoothUserNotification*)notification
+                    channel:(IOBluetoothRFCOMMChannel*)rfcommChannel {
+  if (notification != rfcommNewChannelNotification_) {
+    // This case is reachable if there are pre-existing RFCOMM channels open at
+    // the time that the helper is created. In that case, each existing channel
+    // calls into this method with a different notification than the one this
+    // class registered with. Ignore those; this class is only interested in
+    // channels that have opened since it registered for notifications.
+    return;
+  }
+
+  profile_->OnRFCOMMChannelOpened(rfcommChannel);
+}
+
+@end
 
 namespace device {
 
+BluetoothProfile* CreateBluetoothProfileMac(
+    const BluetoothUUID& uuid,
+    const BluetoothProfile::Options& options) {
+  return new BluetoothProfileMac(uuid, options);
+}
+
 BluetoothProfileMac::BluetoothProfileMac(const BluetoothUUID& uuid,
-                                         const std::string& name)
-    : BluetoothProfile(), uuid_(uuid), name_(name) {
+                                         const Options& options)
+    : uuid_(uuid),
+      rfcomm_channel_id_(options.channel),
+      helper_([[BluetoothProfileMacHelper alloc]
+                initWithProfile:this
+                      channelID:rfcomm_channel_id_]),
+      service_record_handle_(RegisterService(uuid, options)) {
+  // TODO(isherman): What should happen if there was an error registering the
+  // service, i.e. if |service_record_handle_| is |kInvalidServiceRecordHandle|?

[Ilya Sherman, 2014/04/19 05:11:25]

^^^ thoughts?

 }
 
 BluetoothProfileMac::~BluetoothProfileMac() {
+  if (service_record_handle_ != kInvalidServiceRecordHandle)
+    IOBluetoothRemoveServiceWithRecordHandle(service_record_handle_);
 }
 
 void BluetoothProfileMac::Unregister() {
   delete this;
 }
 
 void BluetoothProfileMac::SetConnectionCallback(
     const ConnectionCallback& callback) {
   connection_callback_ = callback;
 }
 
 void BluetoothProfileMac::Connect(
     IOBluetoothDevice* device,
     const base::Closure& success_callback,
     const BluetoothSocket::ErrorCompletionCallback& error_callback) {
   if (connection_callback_.is_null()) {
     error_callback.Run(kNoConnectionCallback);
     return;
   }
 
   IOBluetoothSDPServiceRecord* record = [device
       getServiceRecordForUUID:GetIOBluetoothSDPUUID(uuid_.canonical_value())];
   if (record == nil) {
     error_callback.Run(kProfileNotFound);
     return;
   }
 
   std::string device_address = base::SysNSStringToUTF8([device addressString]);
-  scoped_refptr<BluetoothSocketMac> socket(
-      BluetoothSocketMac::CreateBluetoothSocket(record));
-  socket->Connect(
+  BluetoothSocketMac::Connect(
+      record,
       base::Bind(OnConnectSuccess,
                  success_callback,
                  connection_callback_,
-                 device_address,
-                 socket),
+                 device_address),
       error_callback);
 }
 
+void BluetoothProfileMac::OnRFCOMMChannelOpened(
+    IOBluetoothRFCOMMChannel* rfcomm_channel) {
+  DCHECK_EQ([rfcomm_channel getChannelID], rfcomm_channel_id_);
+  std::string device_address =
+      base::SysNSStringToUTF8([[rfcomm_channel getDevice] addressString]);
+  BluetoothSocketMac::AcceptConnection(
+      rfcomm_channel,
+      base::Bind(OnConnectSuccess,
+                 base::Closure(),
+                 connection_callback_,
+                 device_address),
+      BluetoothSocket::ErrorCompletionCallback());
+
+  // TODO(isherman): Currently, both the profile and the socket remain alive
+  // even after the app that requested them is closed. That's not great, as a
+  // misbehaving app could saturate all of the system's RFCOMM channels, and
+  // then they would not be freed until the user restarts Chrome.
+  // TODO(isherman): Likewise, the socket currently remains alive even if the
+  // underlying rfcomm_channel is closed, e.g. via the client disconnecting, or
+  // the user closing the Bluetooth connection via the system menu. This
+  // functions essentially as a minor memory leak.

[Ilya Sherman, 2014/04/19 05:11:25]

^^^ Thoughts?

+}
+
 }  // namespace device