Read characteristic implementation on macOS

device/bluetooth/bluetooth_remote_gatt_characteristic_mac.h

 // Copyright 2016 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.
 
 #ifndef DEVICE_BLUETOOTH_BLUETOOTH_REMOTE_GATT_CHARACTERISTIC_MAC_H_
 #define DEVICE_BLUETOOTH_BLUETOOTH_REMOTE_GATT_CHARACTERISTIC_MAC_H_
 
 #include "device/bluetooth/bluetooth_remote_gatt_characteristic.h"
 
 #include "base/mac/scoped_nsobject.h"
@@ skipping 34 matching lines @@
   void WriteRemoteCharacteristic(const std::vector<uint8_t>& new_value,
                                  const base::Closure& callback,
                                  const ErrorCallback& error_callback) override;
 
   DISALLOW_COPY_AND_ASSIGN(BluetoothRemoteGattCharacteristicMac);
 
  private:
   friend class BluetoothRemoteGattServiceMac;
   friend class BluetoothTestMac;
 
+  // Called by the BluetoothRemoteGattServiceMac instance when the
+  // characteristics value has been read.
+  void DidUpdateValue(NSError* error);
+  // Returns true if the characteristic is readable.
+  bool IsReadable() const;
   // Returns CoreBluetooth characteristic.
   CBCharacteristic* GetCBCharacteristic() const;
 
   // gatt_service_ owns instances of this class.
   BluetoothRemoteGattServiceMac* gatt_service_;
   // A characteristic from CBPeripheral.services.characteristics.
   base::scoped_nsobject<CBCharacteristic> cb_characteristic_;
   // Characteristic identifier.
   std::string identifier_;
   // Service UUID.
   BluetoothUUID uuid_;
   // Characteristic value.
   std::vector<uint8_t> value_;
+  // True if a gatt read or write request is in progress.
+  bool characteristic_value_read_or_write_in_progress_;
+  // ReadRemoteCharacteristic request callbacks.
+  std::pair<ValueCallback, ErrorCallback> read_characteristic_value_callbacks_;
 };
 
 }  // namespace device
 
 #endif  // DEVICE_BLUETOOTH_BLUETOOTH_REMOTE_GATT_CHARACTERISTIC_MAC_H_