device/bluetooth: Update GATT descriptor value D-Bus bindings.

chromeos/dbus/bluetooth_gatt_descriptor_client.h

 // 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.
 
 #ifndef CHROMEOS_DBUS_BLUETOOTH_GATT_DESCRIPTOR_CLIENT_H_
 #define CHROMEOS_DBUS_BLUETOOTH_GATT_DESCRIPTOR_CLIENT_H_
 
 #include <string>
 
 #include "base/basictypes.h"
+#include "base/callback.h"
 #include "chromeos/chromeos_export.h"
 #include "chromeos/dbus/dbus_client.h"
 #include "dbus/object_path.h"
 #include "dbus/property.h"
 
 namespace chromeos {
 
 // BluetoothGattDescriptorClient is used to communicate with remote GATT
 // characteristic descriptor objects exposed by the Bluetooth daemon.
 class CHROMEOS_EXPORT BluetoothGattDescriptorClient : public DBusClient {
  public:
   // Structure of properties associated with GATT descriptors.
   struct Properties : public dbus::PropertySet {
     // The 128-bit characteristic descriptor UUID. [read-only]
     dbus::Property<std::string> uuid;
 
     // Object path of the GATT characteristic the descriptor belongs to.
     // [read-only]
     dbus::Property<dbus::ObjectPath> characteristic;
 
-    // Raw characteristic descriptor value read from the remote Bluetooth
-    // device. Setting the value sends a write request to the remote device.
-    // [read-write]
-    dbus::Property<std::vector<uint8> > value;
-
     Properties(dbus::ObjectProxy* object_proxy,
                const std::string& interface_name,
                const PropertyChangedCallback& callback);
     virtual ~Properties();
   };
 
   // Interface for observing changes from a remote GATT characteristic
   // descriptor.
   class Observer {
    public:
     virtual ~Observer() {}
 
     // Called when the GATT descriptor with object path |object_path| is added
     // to the system.
     virtual void GattDescriptorAdded(const dbus::ObjectPath& object_path) {}
 
     // Called when the GATT descriptor with object path |object_path| is removed
     // from the system.
     virtual void GattDescriptorRemoved(const dbus::ObjectPath& object_path) {}
 
     // Called when the GATT descriptor with object path |object_path| has a
     // change in the value of the property named |property_name|.
     virtual void GattDescriptorPropertyChanged(
         const dbus::ObjectPath& object_path,
         const std::string& property_name) {}
   };
 
+  // Callbacks used to report the result of asynchronous methods.
+  typedef base::Callback<void(const std::string& error_name,
+                              const std::string& error_message)> ErrorCallback;
+  typedef base::Callback<void(const std::vector<uint8>& value)> ValueCallback;
+
   virtual ~BluetoothGattDescriptorClient();
 
   // Adds and removes observers for events on all remote GATT descriptors. Check
   // the |object_path| parameter of observer methods to determine which GATT
   // descriptor is issuing the event.
   virtual void AddObserver(Observer* observer) = 0;
   virtual void RemoveObserver(Observer* observer) = 0;
 
   // Returns the list of GATT descriptor object paths known to the system.
   virtual std::vector<dbus::ObjectPath> GetDescriptors() = 0;
 
   // Obtain the properties for the GATT descriptor with object path
   // |object_path|. Values should be copied if needed.
   virtual Properties* GetProperties(const dbus::ObjectPath& object_path) = 0;
 
+  // Issues a request to read the value of GATT descriptor with object path
+  // |object_path| and returns the value in |callback| on success. On error,
+  // invokes |error_callback|.
+  virtual void ReadValue(const dbus::ObjectPath& object_path,
+                         const ValueCallback& callback,
+                         const ErrorCallback& error_callback) = 0;
+
+  // Issues a request to write the value of GATT descriptor with object path
+  // |object_path| with value |value|. Invokes |callback| on success and
+  // |error_callback| on failure.
+  virtual void WriteValue(const dbus::ObjectPath& object_path,
+                          const std::vector<uint8>& value,
+                          const base::Closure& callback,
+                          const ErrorCallback& error_callback) = 0;
+
   // Creates the instance.
   static BluetoothGattDescriptorClient* Create();
 
+  // Constants used to indicate exceptional error conditions.
+  static const char kNoResponseError[];
+  static const char kUnknownDescriptorError[];
+
  protected:
   BluetoothGattDescriptorClient();
 
  private:
   DISALLOW_COPY_AND_ASSIGN(BluetoothGattDescriptorClient);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROMEOS_DBUS_BLUETOOTH_GATT_DESCRIPTOR_CLIENT_H_