btsdpinquiry.mm

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// Copyright (C) 2022 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
 
#include "qbluetoothserviceinfo.h"
#include "btsdpinquiry_p.h"
#include "qbluetoothuuid.h"
#include "btdelegates_p.h"
#include "btutility_p.h"
 
#include <QtCore/qoperatingsystemversion.h>
#include <QtCore/qvariant.h>
#include <QtCore/qstring.h>
#include <QtCore/qtimer.h>
 
#include <memory>
 
QT_BEGIN_NAMESPACE
 
namespace DarwinBluetooth {
 
namespace {
 
const int basebandConnectTimeoutMS = 20000;
 
QBluetoothUuid sdp_element_to_uuid(IOBluetoothSDPDataElement *element)
{
    QT_BT_MAC_AUTORELEASEPOOL;
 
    if (!element || [element getTypeDescriptor] != kBluetoothSDPDataElementTypeUUID)
        return {};
 
    return qt_uuid([[element getUUIDValue] getUUIDWithLength:16]);
}
 
QBluetoothUuid extract_service_ID(IOBluetoothSDPServiceRecord *record)
{
    Q_ASSERT(record);
 
    QT_BT_MAC_AUTORELEASEPOOL;
 
    return sdp_element_to_uuid([record getAttributeDataElement:kBluetoothSDPAttributeIdentifierServiceID]);
}
 
QList<QBluetoothUuid> extract_service_class_ID_list(IOBluetoothSDPServiceRecord *record)
{
    Q_ASSERT(record);
 
    QT_BT_MAC_AUTORELEASEPOOL;
 
    IOBluetoothSDPDataElement *const idList = [record getAttributeDataElement:kBluetoothSDPAttributeIdentifierServiceClassIDList];
 
    QList<QBluetoothUuid> uuids;
    if (!idList)
        return uuids;
 
    NSArray *arr = nil;
    if ([idList getTypeDescriptor] == kBluetoothSDPDataElementTypeDataElementSequence)
        arr = [idList getArrayValue];
    else if ([idList getTypeDescriptor] == kBluetoothSDPDataElementTypeUUID)
        arr = @[idList];
 
    if (!arr)
        return uuids;
 
    for (IOBluetoothSDPDataElement *dataElement in arr) {
        const auto qtUuid = sdp_element_to_uuid(dataElement);
        if (!qtUuid.isNull())
            uuids.push_back(qtUuid);
    }
 
    return uuids;
}
 
QBluetoothServiceInfo::Sequence service_class_ID_list_to_sequence(const QList<QBluetoothUuid> &uuids)
{
    if (uuids.isEmpty())
        return {};
 
    QBluetoothServiceInfo::Sequence sequence;
    for (const auto &uuid : uuids) {
        Q_ASSERT(!uuid.isNull());
        sequence.append(QVariant::fromValue(uuid));
    }
 
    return sequence;
}
 
} // unnamed namespace
 
QVariant extract_attribute_value(IOBluetoothSDPDataElement *dataElement)
{
    Q_ASSERT_X(dataElement, Q_FUNC_INFO, "invalid data element (nil)");
 
    // TODO: error handling and diagnostic messages.
 
    // All "temporary" obj-c objects are autoreleased.
    QT_BT_MAC_AUTORELEASEPOOL;
 
    const BluetoothSDPDataElementTypeDescriptor typeDescriptor = [dataElement getTypeDescriptor];
 
    switch (typeDescriptor) {
    case kBluetoothSDPDataElementTypeNil:
        break;
    case kBluetoothSDPDataElementTypeUnsignedInt:
        return [[dataElement getNumberValue] unsignedIntValue];
    case kBluetoothSDPDataElementTypeSignedInt:
        return [[dataElement getNumberValue] intValue];
    case kBluetoothSDPDataElementTypeUUID:
        return QVariant::fromValue(sdp_element_to_uuid(dataElement));
    case kBluetoothSDPDataElementTypeString:
    case kBluetoothSDPDataElementTypeURL:
        return QString::fromNSString([dataElement getStringValue]);
    case kBluetoothSDPDataElementTypeBoolean:
        return [[dataElement getNumberValue] boolValue];
    case kBluetoothSDPDataElementTypeDataElementSequence:
    case kBluetoothSDPDataElementTypeDataElementAlternative: // TODO: check this!
        {
        QBluetoothServiceInfo::Sequence sequence;
        NSArray *const arr = [dataElement getArrayValue];
        for (IOBluetoothSDPDataElement *element in arr)
            sequence.append(extract_attribute_value(element));
 
        return QVariant::fromValue(sequence);
        }
        break;// Coding style.
    default:;
    }
 
    return QVariant();
}
 
void extract_service_record(IOBluetoothSDPServiceRecord *record, QBluetoothServiceInfo &serviceInfo)
{
    QT_BT_MAC_AUTORELEASEPOOL;
 
    if (!record)
        return;
 
    NSDictionary *const attributes = record.attributes;
    NSEnumerator *const keys = attributes.keyEnumerator;
    for (NSNumber *key in keys) {
        const quint16 attributeID = [key unsignedShortValue];
        IOBluetoothSDPDataElement *const element = [attributes objectForKey:key];
        const QVariant attributeValue = DarwinBluetooth::extract_attribute_value(element);
        serviceInfo.setAttribute(attributeID, attributeValue);
    }
 
    const QBluetoothUuid serviceUuid = extract_service_ID(record);
    if (!serviceUuid.isNull())
        serviceInfo.setServiceUuid(serviceUuid);
 
    const QList<QBluetoothUuid> uuids(extract_service_class_ID_list(record));
    const auto sequence = service_class_ID_list_to_sequence(uuids);
    if (!sequence.isEmpty())
        serviceInfo.setAttribute(QBluetoothServiceInfo::ServiceClassIds, sequence);
}
 
QList<QBluetoothUuid> extract_services_uuids(IOBluetoothDevice *device)
{
    QList<QBluetoothUuid> uuids;
 
    // All "temporary" obj-c objects are autoreleased.
    QT_BT_MAC_AUTORELEASEPOOL;
 
    if (!device || !device.services)
        return uuids;
 
    NSArray * const records = device.services;
    for (IOBluetoothSDPServiceRecord *record in records) {
        const QBluetoothUuid serviceID = extract_service_ID(record);
        if (!serviceID.isNull())
            uuids.push_back(serviceID);
 
        const QList<QBluetoothUuid> idList(extract_service_class_ID_list(record));
        if (idList.size())
            uuids.append(idList);
    }
 
    return uuids;
}
 
} // namespace DarwinBluetooth
 
QT_END_NAMESPACE
 
QT_USE_NAMESPACE
 
using namespace DarwinBluetooth;
 
@implementation DarwinBTSDPInquiry
{
    QT_PREPEND_NAMESPACE(DarwinBluetooth::SDPInquiryDelegate) *delegate;
    ObjCScopedPointer<IOBluetoothDevice> device;
    bool isActive;
 
    // Needed to workaround a broken SDP on Monterey:
    std::unique_ptr<QTimer> connectionWatchdog;
}
 
- (id)initWithDelegate:(DarwinBluetooth::SDPInquiryDelegate *)aDelegate
{
    Q_ASSERT_X(aDelegate, Q_FUNC_INFO, "invalid delegate (null)");
 
    if (self = [super init]) {
        delegate = aDelegate;
        isActive = false;
    }
 
    return self;
}
 
- (void)dealloc
{
    //[device closeConnection]; //??? - synchronous, "In the future this API will be changed to allow asynchronous operation."
    [super dealloc];
}
 
- (IOReturn)performSDPQueryWithDevice:(const QBluetoothAddress &)address
{
    Q_ASSERT_X(!isActive, Q_FUNC_INFO, "SDP query in progress");
 
    QList<QBluetoothUuid> emptyFilter;
    return [self performSDPQueryWithDevice:address filters:emptyFilter];
}
 
- (void)interruptSDPQuery
{
    // To be only executed on timer.
    Q_ASSERT(connectionWatchdog.get());
    // If device was reset, so the timer should be, we can never be here then.
    Q_ASSERT(device.get());
 
    Q_ASSERT_X(delegate, Q_FUNC_INFO, "invalid delegate (null)");
    qCDebug(QT_BT_DARWIN) << "couldn't connect to device" << [device nameOrAddress]
                          << ", ending SDP inquiry.";
 
    // Stop the watchdog and close the connection as otherwise there could be
    // later "connectionComplete" callbacks
    connectionWatchdog->stop();
    [device closeConnection];
 
    delegate->SDPInquiryError(device, kIOReturnTimeout);
    device.reset();
    isActive = false;
}
 
- (IOReturn)performSDPQueryWithDevice:(const QBluetoothAddress &)address
                              filters:(const QList<QBluetoothUuid> &)qtFilters
{
    Q_ASSERT_X(!isActive, Q_FUNC_INFO, "SDP query in progress");
    Q_ASSERT_X(!address.isNull(), Q_FUNC_INFO, "invalid target device address");
    qCDebug(QT_BT_DARWIN) << "Starting and SDP inquiry for address:" << address;
 
    QT_BT_MAC_AUTORELEASEPOOL;
 
    // We first try to allocate "filters":
    ObjCScopedPointer<NSMutableArray> array;
    if (QOperatingSystemVersion::current() <= QOperatingSystemVersion::MacOSBigSur
        && qtFilters.size()) { // See the comment about filters on Monterey below.
        array.reset([[NSMutableArray alloc] init], RetainPolicy::noInitialRetain);
        if (!array) {
            qCCritical(QT_BT_DARWIN) << "failed to allocate an uuid filter";
            return kIOReturnError;
        }
 
        for (const QBluetoothUuid &qUuid : qtFilters) {
            ObjCStrongReference<IOBluetoothSDPUUID> uuid(iobluetooth_uuid(qUuid));
            if (uuid)
                [array addObject:uuid];
        }
 
        if (qsizetype([array count]) != qtFilters.size()) {
            qCCritical(QT_BT_DARWIN) << "failed to create an uuid filter";
            return kIOReturnError;
        }
    }
 
    const BluetoothDeviceAddress iobtAddress(iobluetooth_address(address));
    device.reset([IOBluetoothDevice deviceWithAddress:&iobtAddress], RetainPolicy::doInitialRetain);
    if (!device) {
        qCCritical(QT_BT_DARWIN) << "failed to create an IOBluetoothDevice object";
        return kIOReturnError;
    }
    qCDebug(QT_BT_DARWIN) << "Device" << [device nameOrAddress] << "connected:"
                          << bool([device isConnected]) << "paired:" << bool([device isPaired]);
 
    IOReturn result = kIOReturnSuccess;
 
    if (QOperatingSystemVersion::current() > QOperatingSystemVersion::MacOSBigSur) {
        // SDP query on Monterey does not follow its own documented/expected behavior:
        // - a simple performSDPQuery was previously ensuring baseband connection
        //   to be opened, now it does not do so, instead logs a warning and returns
        //   immediately.
        // - a version with UUID filters simply does nothing except it immediately
        //   returns kIOReturnSuccess.
 
        // If the device was not yet connected, connect it first
        if (![device isConnected]) {
            qCDebug(QT_BT_DARWIN) << "Device" << [device nameOrAddress]
                                  << "is not connected, connecting it first";
            result = [device openConnection:self];
            // The connection may succeed immediately. But if it didn't, start a connection timer
            // which has two guardian roles:
            // 1. Guard against connect attempt taking too long time
            // 2. Sometimes on Monterey the callback indicating "connection completion" is
            //    not received even though the connection has in fact succeeded
            if (![device isConnected]) {
                qCDebug(QT_BT_DARWIN) << "Starting connection monitor for device"
                                      << [device nameOrAddress] << "with timeout limit of"
                                      << basebandConnectTimeoutMS/1000 << "seconds.";
                connectionWatchdog.reset(new QTimer);
                connectionWatchdog->setSingleShot(false);
                QObject::connect(connectionWatchdog.get(), &QTimer::timeout,
                                 connectionWatchdog.get(),
                                 [self] () {
                    qCDebug(QT_BT_DARWIN) << "Connection monitor timeout for device:"
                                          << [device nameOrAddress]
                                          << ", connected:" << bool([device isConnected]);
                    // Device can sometimes get properly connected without IOBluetooth
                    // calling the connectionComplete callback, so we check the status here
                    if ([device isConnected])
                        [self connectionComplete:device status:kIOReturnSuccess];
                    else
                        [self interruptSDPQuery];
                });
                connectionWatchdog->start(basebandConnectTimeoutMS);
            }
         }
 
        if ([device isConnected])
            result = [device performSDPQuery:self];
 
        if (result != kIOReturnSuccess) {
            qCCritical(QT_BT_DARWIN, "failed to start an SDP query");
            device.reset();
        } else {
            isActive = true;
        }
 
        return result;
    } // Monterey's code path.
 
    if (qtFilters.size())
        result = [device performSDPQuery:self uuids:array];
    else
        result = [device performSDPQuery:self];
 
    if (result != kIOReturnSuccess) {
        qCCritical(QT_BT_DARWIN) << "failed to start an SDP query";
        device.reset();
    } else {
        isActive = true;
    }
 
    return result;
}
 
- (void)connectionComplete:(IOBluetoothDevice *)aDevice status:(IOReturn)status
{
    qCDebug(QT_BT_DARWIN) << "connectionComplete for device" << [aDevice nameOrAddress]
                          << "with status:" << status;
    if (aDevice != device) {
        // Connection was previously cancelled, probably, due to the timeout.
        return;
    }
 
    // The connectionComplete may be invoked by either the IOBluetooth callback or our
    // connection watchdog. In either case stop the watchdog if it exists
    if (connectionWatchdog)
        connectionWatchdog->stop();
 
    if (status == kIOReturnSuccess)
        status = [aDevice performSDPQuery:self];
 
    if (status != kIOReturnSuccess) {
        isActive = false;
        qCWarning(QT_BT_DARWIN, "failed to open connection or start an SDP query");
        Q_ASSERT_X(delegate, Q_FUNC_INFO, "invalid delegate (null)");
        delegate->SDPInquiryError(aDevice, status);
    }
}
 
- (void)stopSDPQuery
{
    // There is no API to stop it SDP on device, but there is a 'stop'
    // member-function in Qt and after it's called sdpQueryComplete
    // must be somehow ignored (device != aDevice in a callback).
    device.reset();
    isActive = false;
    connectionWatchdog.reset();
}
 
- (void)sdpQueryComplete:(IOBluetoothDevice *)aDevice status:(IOReturn)status
{
    qCDebug(QT_BT_DARWIN) << "sdpQueryComplete for device:" << [aDevice nameOrAddress]
                          << "with status:" << status;
    // Can happen - there is no legal way to cancel an SDP query,
    // after the 'reset' device can never be
    // the same as the cancelled one.
    if (device != aDevice)
        return;
 
    Q_ASSERT_X(delegate, Q_FUNC_INFO, "invalid delegate (null)");
 
    isActive = false;
 
    // If we used the manual connection establishment, close the
    // connection here. Otherwise the IOBluetooth may call stray
    // connectionComplete or sdpQueryCompletes
    if (connectionWatchdog) {
        qCDebug(QT_BT_DARWIN) << "Closing the connection established for SDP inquiry.";
        connectionWatchdog.reset();
        [device closeConnection];
    }
 
    if (status != kIOReturnSuccess)
        delegate->SDPInquiryError(aDevice, status);
    else
        delegate->SDPInquiryFinished(aDevice);
}
 
@end