/**************************************************************************** ** ** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies). ** Contact: http://www.qt-project.org/legal ** ** This file is part of the QtBluetooth module of the Qt Toolkit. ** ** $QT_BEGIN_LICENSE:LGPL21$ ** Commercial License Usage ** Licensees holding valid commercial Qt licenses may use this file in ** accordance with the commercial license agreement provided with the ** Software or, alternatively, in accordance with the terms contained in ** a written agreement between you and Digia. For licensing terms and ** conditions see http://qt.digia.com/licensing. For further information ** use the contact form at http://qt.digia.com/contact-us. ** ** GNU Lesser General Public License Usage ** Alternatively, this file may be used under the terms of the GNU Lesser ** General Public License version 2.1 or version 3 as published by the Free ** Software Foundation and appearing in the file LICENSE.LGPLv21 and ** LICENSE.LGPLv3 included in the packaging of this file. Please review the ** following information to ensure the GNU Lesser General Public License ** requirements will be met: https://www.gnu.org/licenses/lgpl.html and ** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. ** ** In addition, as a special exception, Digia gives you certain additional ** rights. These rights are described in the Digia Qt LGPL Exception ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package. ** ** $QT_END_LICENSE$ ** ****************************************************************************/ #include #include #include #include #include "qlowenergycontroller_p.h" #include "qlowenergyserviceprivate_p.h" QT_BEGIN_NAMESPACE /*! \class QLowEnergyService \inmodule QtBluetooth \brief The QLowEnergyService class represents an individual service on a Bluetooth Low Energy Device. \since 5.4 QLowEnergyService provides access to the details of Bluetooth Low Energy services. The class facilitates the discovery and publification of service details, permits reading and writing of the contained data and notifies about data changes. \section1 Service Structure A Bluetooth Low Energy peripheral device can contain multiple services. In turn each service may include further services. This class represents a single service of the peripheral device and is created via \l QLowEnergyController::createServiceObject(). The \l type() indicates whether this service is a primary (top-level) service or whether the service is part of another service. Each service may contain one or more characteristics and each characteristic may contain descriptors. The resulting structure may look like the following diagram: \image peripheral-structure.png Structure of a generic peripheral A characteristic is the principle information carrier. It has a \l {QLowEnergyCharacteristic::value()}{value()} and \l {QLowEnergyCharacteristic::value()}{properties()} describing the access permissions for the value. The general purpose of the contained descriptor is to further define the nature of the characteristic. For example, it might specify how the value is meant to be interpreted or whether it can notify the value consumer about value changes. \section1 Service Interaction Once a service object was created for the first time, its details are yet to be discovered. This is indicated by its current \l state() being \l DiscoveryRequired. It is only possible to retrieve the \l serviceUuid() and \l serviceName(). The discovery of its included services, characteristics and descriptors is triggered when calling \l discoverDetails(). During the discovery the \l state() transitions from \l DiscoveryRequired via \l DiscoveringServices to its final \l ServiceDiscovered state. This transition is advertised via the \l stateChanged() signal. Once the details are known, all of the contained characteristics, descriptors and included services are known and can be read or written. The values of characteristics and descriptors can be retrieved via \l QLowEnergyCharacteristic and \l QLowEnergyDescriptor, respectively. However writing those attributes requires the service object. The \l writeCharacteristic() function attempts to write a new value to the given characteristic. If the write attempt is successful, the \l characteristicChanged() signal is emitted. A failure to write triggers the \l CharacteristicWriteError. Writing a descriptor follows the same pattern. \section1 Service Data Sharing Each QLowEnergyService instance shares its internal states and information with other QLowEnergyService instance of the same service. If one instance initiates the discovery of the service details, all remaining instances automatically follow. Therefore the following snippet always works: \snippet doc_src_qtbluetooth.cpp data_share_qlowenergyservice Other operations such as calls to \l writeCharacteristic(), writeDescriptor() or the invalidation of the service due to the related \l QLowEnergyController disconnecting from the device are shared the same way. \sa QLowEnergyController, QLowEnergyCharacteristic, QLowEnergyDescriptor */ /*! \enum QLowEnergyService::ServiceType This enum describes the type of the service. \value PrimaryService The service is a top-level/primary service. If this type flag is not set, the service is considered to be a secondary service. Each service may be included by another service which is indicated by IncludedService. \value IncludedService The service is included by another service. */ /*! \enum QLowEnergyService::ServiceError This enum describes all possible error conditions during the service's existence. The \l error() function returns the last occurred error. \value NoError No error has occurred. \value ServiceNotValidError The service object is invalid and has lost its connection to the peripheral device. \value OperationError An operation was attempted while the service was not ready. An example might be the attempt to write to the service while it was not yet in the \l ServiceDiscovered \l state(). \value CharacteristicWriteError An attempt to write a new value to a characteristic failed. For example, it might be triggered when attempting to write to a read-only characteristic. \value DescriptorWriteError An attempt to write a new value to a descriptor failed. For example, it might be triggered when attempting to write to a read-only descriptor. */ /*! \enum QLowEnergyService::ServiceState This enum describes the \l state() of the service object. \value InvalidService A service can become invalid when it looses the connection to the underlying device. Even though the connection may be lost it retains its last information. An invalid service cannot become valid anymore even if the connection to the device is re-established. \value DiscoveryRequired The service details are yet to be discovered by calling \l discoverDetails(). The only reliable pieces of information are its \l serviceUuid() and \l serviceName(). \value DiscoveringServices The service details are being discovered. \value ServiceDiscovered The service details have been discovered. */ /*! \fn void QLowEnergyService::stateChanged(QLowEnergyService::ServiceState newState) This signal is emitted when the service's state changes. The \a newState can also be retrieved via \l state(). \sa state() */ /*! \fn void QLowEnergyService::error(QLowEnergyService::ServiceError newError) This signal is emitted when an error occurrs. The \a newError parameter describes the error that occurred. */ /*! \fn void QLowEnergyService::characteristicChanged(const QLowEnergyCharacteristic &characteristic, const QByteArray &newValue); This signal is emitted when the value of \a characteristic is successfully changed to \a newValue. The change may have been caused by calling \l writeCharacteristic() or otherwise triggering a change notification on the peripheral device. \sa writeCharacteristic() */ /*! \fn void QLowEnergyService::descriptorChanged(const QLowEnergyDescriptor &descriptor, const QByteArray &newValue) This signal is emitted when the value of \a descriptor is successfully changed to \a newValue. The change may have been caused by calling \l writeDescriptor() or otherwise triggering a change notification on the peripheral device. \sa writeDescriptor() */ /*! \internal QLowEnergyControllerPrivate creates instances of this class. The user gets access to class instances via \l QLowEnergyController::services(). */ QLowEnergyService::QLowEnergyService(QSharedPointer p, QObject *parent) : QObject(parent), d_ptr(p) { qRegisterMetaType("QLowEnergyService::ServiceState"); qRegisterMetaType("QLowEnergyService::ServiceError"); connect(p.data(), SIGNAL(error(QLowEnergyService::ServiceError)), this, SIGNAL(error(QLowEnergyService::ServiceError))); connect(p.data(), SIGNAL(stateChanged(QLowEnergyService::ServiceState)), this, SIGNAL(stateChanged(QLowEnergyService::ServiceState))); connect(p.data(), SIGNAL(characteristicChanged(QLowEnergyCharacteristic,QByteArray)), this, SIGNAL(characteristicChanged(QLowEnergyCharacteristic,QByteArray))); connect(p.data(), SIGNAL(descriptorChanged(QLowEnergyDescriptor,QByteArray)), this, SIGNAL(descriptorChanged(QLowEnergyDescriptor,QByteArray))); } /*! Destroys the \l QLowEnergyService instance. */ QLowEnergyService::~QLowEnergyService() { } /*! Returns the UUIDs of all services which are included by the current service. It is possible that an included service contains yet another service. Such second level includes have to be obtained via their relevant first level QLowEnergyService instance. Technically, this could create a circular dependency. \l {QLowEnergyController::createServiceObject()} should be used to obtain service instances for each of the UUIDs. \sa createServiceObject() */ QList QLowEnergyService::includedServices() const { return d_ptr->includedServices; } /*! Returns the current state of the service. If the device's service was instantiated for the first time, the object's state is \l DiscoveryRequired. The state of all service objects which point to the same service on the peripheral device are always equal. This is caused by the shared nature of the internal object data. Therefore any service object instance created after the first one has a state equal to already existing instances. A service becomes invalid if the \l QLowEnergyController disconnects from the remote device. An invalid service retains its internal state at the time of the disconnect event. This implies that once the service details are discovered they can even be retrieved from an invalid service. This permits scenarios where the device connection is established, the service details are retrieved and the device immediately disconnected to permit the next device to connect to the peripheral device. However, under normal circumstances the connection should remain to avoid repeated discovery of services and their details. The discovery may take a while and the client can subscribe to ongoing change notifications. \sa stateChanged() */ QLowEnergyService::ServiceState QLowEnergyService::state() const { return d_ptr->state; } /*! Returns the type of the service. */ QLowEnergyService::ServiceTypes QLowEnergyService::type() const { return d_ptr->type; } /*! Returns the matching characteristic for \a uuid; otherwise an invalid characteristic. \sa characteristics() */ QLowEnergyCharacteristic QLowEnergyService::characteristic(const QBluetoothUuid &uuid) const { foreach (const QLowEnergyHandle handle, d_ptr->characteristicList.keys()) { if (d_ptr->characteristicList[handle].uuid == uuid) return QLowEnergyCharacteristic(d_ptr, handle); } return QLowEnergyCharacteristic(); } /*! Returns all characteristics associated with this \c QLowEnergyService instance. The returned list is empty if this service instance's \l discoverDetails() was not yet called or there are no known characteristics. \sa characteristic(), state(), discoverDetails() */ QList QLowEnergyService::characteristics() const { QList results; QList handles = d_ptr->characteristicList.keys(); std::sort(handles.begin(), handles.end()); foreach (const QLowEnergyHandle &handle, handles) { QLowEnergyCharacteristic characteristic(d_ptr, handle); results.append(characteristic); } return results; } /*! Returns the UUID of the service; otherwise a null UUID. */ QBluetoothUuid QLowEnergyService::serviceUuid() const { return d_ptr->uuid; } /*! Returns the name of the service; otherwise an empty string. The returned name can only be retrieved if \l serviceUuid() is a \l {https://developer.bluetooth.org/gatt/services/Pages/ServicesHome.aspx}{well-known UUID}. */ QString QLowEnergyService::serviceName() const { bool ok = false; quint16 clsId = d_ptr->uuid.toUInt16(&ok); if (ok) { QBluetoothUuid::ServiceClassUuid id = static_cast(clsId); const QString name = QBluetoothUuid::serviceClassToString(id); if (!name.isEmpty()) return name; } return qApp ? qApp->translate("QBluetoothServiceDiscoveryAgent", "Unknown Service") : QStringLiteral("Unknown Service"); } /*! Initiates the discovery of the services, characteristics and descriptors contained by the service. The discovery process is indicated via the \l stateChanged() signal. \sa state() */ void QLowEnergyService::discoverDetails() { Q_D(QLowEnergyService); if (!d->controller || d->state == QLowEnergyService::InvalidService) { d->setError(QLowEnergyService::ServiceNotValidError); return; } if (d->state != QLowEnergyService::DiscoveryRequired) return; d->setState(QLowEnergyService::DiscoveringServices); d->controller->discoverServiceDetails(d->uuid); } /*! Returns the last occurred error or \l NoError. */ QLowEnergyService::ServiceError QLowEnergyService::error() const { return d_ptr->lastError; } /*! Returns \c true if \a characteristic belongs to this service; otherwise \c false. A characteristic belongs to a service if \l characteristics() contains the \a characteristic. */ bool QLowEnergyService::contains(const QLowEnergyCharacteristic &characteristic) const { if (characteristic.d_ptr.isNull() || !characteristic.data) return false; if (d_ptr == characteristic.d_ptr && d_ptr->characteristicList.contains(characteristic.attributeHandle())) { return true; } return false; } /*! Writes \a newValue as value for the \a characteristic. If the operation is successful, the \l characteristicChanged() signal is emitted. A characteristic can only be written if this service is in the \l ServiceDiscovered state, belongs to the service and is writable. */ void QLowEnergyService::writeCharacteristic( const QLowEnergyCharacteristic &characteristic, const QByteArray &newValue) { //TODO check behavior when writing to WriteNoResponse characteristic //TODO check behavior when writing to WriteSigned characteristic //TODO add support for write long characteristic value (newValue.size() > MTU - 3) Q_D(QLowEnergyService); // not a characteristic of this service if (!contains(characteristic)) return; // don't write if we don't have to if (characteristic.value() == newValue) return; // don't write write-protected or undiscovered characteristic if (!(characteristic.properties() & QLowEnergyCharacteristic::Write) || state() != ServiceDiscovered) { d->setError(QLowEnergyService::OperationError); return; } if (!d->controller) return; d->controller->writeCharacteristic(characteristic.d_ptr, characteristic.attributeHandle(), newValue); } /*! Returns \c true if \a descriptor belongs to this service; otherwise \c false. */ bool QLowEnergyService::contains(const QLowEnergyDescriptor &descriptor) const { if (descriptor.d_ptr.isNull() || !descriptor.data) return false; const QLowEnergyHandle charHandle = descriptor.characteristicHandle(); if (!charHandle) return false; if (d_ptr == descriptor.d_ptr && d_ptr->characteristicList.contains(charHandle) && d_ptr->characteristicList[charHandle].descriptorList.contains(descriptor.handle())) { return true; } return false; } /*! Writes \a newValue as value for \a descriptor. If the operation is successful, the \l descriptorChanged() signal is emitted. A descriptor can only be written if this service is in the \l ServiceDiscovered state, belongs to the service and is writable. */ void QLowEnergyService::writeDescriptor(const QLowEnergyDescriptor &descriptor, const QByteArray &newValue) { //TODO not all descriptors are writable (how to deal with write errors) Q_D(QLowEnergyService); if (!contains(descriptor)) return; if (descriptor.value() == newValue) return; if (state() != ServiceDiscovered || !d->controller) { d->setError(QLowEnergyService::OperationError); return; } d->controller->writeDescriptor(descriptor.d_ptr, descriptor.characteristicHandle(), descriptor.handle(), newValue); } QT_END_NAMESPACE