// 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_SERVICE_PROVIDER_H_
#define CHROMEOS_DBUS_BLUETOOTH_GATT_DESCRIPTOR_SERVICE_PROVIDER_H_
#include <string>
#include <vector>
#include "base/basictypes.h"
#include "base/callback.h"
#include "chromeos/chromeos_export.h"
#include "dbus/bus.h"
#include "dbus/object_path.h"
namespace chromeos {
// BluetoothGattDescriptorServiceProvider is used to provide a D-Bus object that
// represents a local GATT characteristic descriptor that the Bluetooth daemon
// can communicate with.
//
// Instantiate with a chosen D-Bus object path, delegate, and other fields.
// The Bluetooth daemon communicates with a GATT descriptor using the
// standard DBus.Properties interface. While most properties of the GATT
// descriptor interface are read-only and don't change throughout the
// life-time of the object, the "Value" property is both writeable and its
// value can change. Both Get and Set operations performed on the "Value"
// property are delegated to the Delegate object, an instance of which is
// mandatory during initialization. In addition, a "SendValueChanged" method is
// provided, which emits a DBus.Properties.PropertyChanged signal for the
// "Value" property.
class CHROMEOS_EXPORT BluetoothGattDescriptorServiceProvider {
public:
// Interface for reacting to GATT characteristic descriptor value requests.
class Delegate {
public:
virtual ~Delegate() {}
// ValueCallback is used for methods that require a descriptor value
// to be returned.
typedef base::Callback<void(const std::vector<uint8>&)> ValueCallback;
// ErrorCallback is used by methods to report failure.
typedef base::Closure ErrorCallback;
// This method will be called when a remote device requests to read the
// value of the exported GATT descriptor. Invoke |callback| with a value
// to return that value to the requester. Invoke |error_callback| to report
// a failure to read the value. This can happen, for example, if the
// descriptor has no read permission set. Either callback should be
// invoked after a reasonable amount of time, since the request will time
// out if left pending for too long.
virtual void GetDescriptorValue(const ValueCallback& callback,
const ErrorCallback& error_callback) = 0;
// This method will be called, when a remote device requests to write the
// value of the exported GATT descriptor. Invoke |callback| to report
// that the value was successfully written. Invoke |error_callback| to
// report a failure to write the value. This can happen, for example, if the
// descriptor has no write permission set. Either callback should be
// invoked after a reasonable amount of time, since the request will time
// out if left pending for too long.
//
// The delegate should use this method to perform any side-effects that may
// occur based on the set value and potentially send a property changed
// signal to notify the Bluetooth daemon that the value has changed.
virtual void SetDescriptorValue(const std::vector<uint8>& value,
const base::Closure& callback,
const ErrorCallback& error_callback) = 0;
};
virtual ~BluetoothGattDescriptorServiceProvider();
// Send a PropertyChanged signal to notify the Bluetooth daemon that the value
// of the "Value" property has changed to |value|.
virtual void SendValueChanged(const std::vector<uint8>& value) = 0;
// Creates the instance, where |bus| is the D-Bus bus connection to export
// the object onto, |uuid| is the 128-bit GATT descriptor UUID, |permissions|
// is the list of attribute permissions, |characteristic_path| is the object
// path of the exported GATT characteristic the descriptor belongs to,
// |object_path| is the object path that the descriptor should have, and
// |delegate| is the object that value Get/Set requests will be passed to and
// responses generated from.
//
// Object paths of GATT descriptors must be hierarchical to the path of the
// GATT characteristic they belong to. Hence, |object_path| must have
// |characteristic_path| as its prefix. Ownership of |delegate| is not taken,
// thus the delegate should outlive this instance. A delegate should handle
// only a single exported descriptor and own it.
static BluetoothGattDescriptorServiceProvider* Create(
dbus::Bus* bus,
const dbus::ObjectPath& object_path,
Delegate* delegate,
const std::string& uuid,
const std::vector<std::string>& permissions,
const dbus::ObjectPath& characteristic_path);
protected:
BluetoothGattDescriptorServiceProvider();
private:
DISALLOW_COPY_AND_ASSIGN(BluetoothGattDescriptorServiceProvider);
};
} // namespace chromeos
#endif // CHROMEOS_DBUS_BLUETOOTH_GATT_DESCRIPTOR_SERVICE_PROVIDER_H_