1 // Copyright 2014 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef CHROMEOS_DBUS_BLUETOOTH_GATT_CHARACTERISTIC_SERVICE_PROVIDER_H_ 6 #define CHROMEOS_DBUS_BLUETOOTH_GATT_CHARACTERISTIC_SERVICE_PROVIDER_H_ 7 8 #include <string> 9 #include <vector> 10 11 #include "base/basictypes.h" 12 #include "base/callback.h" 13 #include "chromeos/chromeos_export.h" 14 #include "dbus/bus.h" 15 #include "dbus/object_path.h" 16 17 namespace chromeos { 18 19 // BluetoothGattCharacteristicServiceProvider is used to provide a D-Bus object 20 // that represents a local GATT characteristic that the Bluetooth daemon can 21 // communicate with. 22 // 23 // Instantiate with a chosen D-Bus object path, delegate, and other fields. 24 // The Bluetooth daemon communicates with a GATT characteristic using the 25 // standard DBus.Properties interface. While most properties of the GATT 26 // characteristic interface are read-only and don't change throughout the 27 // life-time of the object, the "Value" property is both writeable and its 28 // value can change. Both Get and Set operations performed on the "Value" 29 // property are delegated to the Delegate object, an instance of which is 30 // mandatory during initialization. In addition, a "SendValueChanged" method is 31 // provided, which emits a DBus.Properties.PropertyChanged signal for the 32 // "Value" property. 33 class CHROMEOS_EXPORT BluetoothGattCharacteristicServiceProvider { 34 public: 35 // Interface for reacting to GATT characteristic value requests. 36 class Delegate { 37 public: 38 virtual ~Delegate() {} 39 40 // ValueCallback is used for methods that require a characteristic value 41 // to be returned. 42 typedef base::Callback<void(const std::vector<uint8>&)> ValueCallback; 43 44 // ErrorCallback is used by methods to report failure. 45 typedef base::Closure ErrorCallback; 46 47 // This method will be called when a remote device requests to read the 48 // value of the exported GATT characteristic. Invoke |callback| with a value 49 // to return that value to the requester. Invoke |error_callback| to report 50 // a failure to read the value. This can happen, for example, if the 51 // characteristic has no read permission set. Either callback should be 52 // invoked after a reasonable amount of time, since the request will time 53 // out if left pending for too long. 54 virtual void GetCharacteristicValue( 55 const ValueCallback& callback, 56 const ErrorCallback& error_callback) = 0; 57 58 // This method will be called, when a remote device requests to write the 59 // value of the exported GATT characteristic. Invoke |callback| to report 60 // that the value was successfully written. Invoke |error_callback| to 61 // report a failure to write the value. This can happen, for example, if the 62 // characteristic has no write permission set. Either callback should be 63 // invoked after a reasonable amount of time, since the request will time 64 // out if left pending for too long. 65 // 66 // The delegate should use this method to perform any side-effects that may 67 // occur based on the set value and potentially send a property changed 68 // signal to notify the Bluetooth daemon that the value has changed. 69 virtual void SetCharacteristicValue( 70 const std::vector<uint8>& value, 71 const base::Closure& callback, 72 const ErrorCallback& error_callback) = 0; 73 }; 74 75 virtual ~BluetoothGattCharacteristicServiceProvider(); 76 77 // Send a PropertyChanged signal to notify the Bluetooth daemon that the value 78 // of the "Value" property has changed to |value|. 79 virtual void SendValueChanged(const std::vector<uint8>& value) = 0; 80 81 // Creates the instance, where |bus| is the D-Bus bus connection to export 82 // the object onto, |uuid| is the 128-bit GATT characteristic UUID, 83 // |flags| is the list of GATT characteristic properties, |permissions| is the 84 // list of attribute permissions, |service_path| is the object path of the 85 // exported GATT service the characteristic belongs to, |object_path| is the 86 // object path that the characteristic should have, and |delegate| is the 87 // object that "Value" Get/Set requests will be passed to and responses 88 // generated from. 89 // 90 // Object paths of GATT characteristics must be hierarchical to the path of 91 // the GATT service they belong to. Hence, |object_path| must have 92 // |service_path| as its prefix. Ownership of |delegate| is not taken, thus 93 // the delegate should outlive this instance. A delegate should handle only 94 // a single exported characteristic and own it. 95 static BluetoothGattCharacteristicServiceProvider* Create( 96 dbus::Bus* bus, 97 const dbus::ObjectPath& object_path, 98 Delegate* delegate, 99 const std::string& uuid, 100 const std::vector<std::string>& flags, 101 const std::vector<std::string>& permissions, 102 const dbus::ObjectPath& service_path); 103 104 protected: 105 BluetoothGattCharacteristicServiceProvider(); 106 107 private: 108 DISALLOW_COPY_AND_ASSIGN(BluetoothGattCharacteristicServiceProvider); 109 }; 110 111 } // namespace chromeos 112 113 #endif // CHROMEOS_DBUS_BLUETOOTH_GATT_CHARACTERISTIC_SERVICE_PROVIDER_H_ 114