QtBluetooth - add LE device discovery timeout (OS X/iOS)

- Instead of hardcoded 10 second timeout use the latest Qt API enabling
  arbitrary or infinite length for LE device discovery.
- Since now scan can take long or unlimited time, the previous approach
  with detached CBCentralManager and DDA is not working anymore -
  we can not report devices only at the end of scan.
  Re-use LENotifier and signals/slots instead.
- Remove DDA timer, timeout logic is completely inside
  osxbtledeviceinquiry object now.

Change-Id: I07735581ac175d1d5e5d788aaf697dcb41429e31
Reviewed-by: Alex Blasche <alexander.blasche@theqtcompany.com>

10 files changed, 220 insertions, 376 deletions

diff --git a/src/bluetooth/bluetooth.pro b/src/bluetooth/bluetooth.pro
index a614516f..3bca5496 100644
--- a/src/bluetooth/bluetooth.pro
+++ b/src/bluetooth/bluetooth.pro
@@ -152,14 +152,10 @@ config_bluez:qtHaveModule(dbus) {
         qlowenergycontroller_osx.mm \
         qlowenergyservice_osx.mm
 
-    SOURCES += \
-        qlowenergycontroller_p.cpp
-
     PRIVATE_HEADERS += qbluetoothsocket_osx_p.h \
                        qbluetoothserver_osx_p.h \
                        qbluetoothtransferreply_osx_p.h \
                        qbluetoothtransferreply_osx_p.h \
-                       qbluetoothdevicediscoverytimer_osx_p.h \
                        qlowenergycontroller_osx_p.h
 
     SOURCES -= qbluetoothdevicediscoveryagent.cpp
@@ -181,8 +177,7 @@ config_bluez:qtHaveModule(dbus) {
         qlowenergyservice_osx.mm
 
     PRIVATE_HEADERS += \
-        qlowenergycontroller_osx_p.h \
-        qbluetoothdevicediscoverytimer_osx_p.h
+        qlowenergycontroller_osx_p.h
 
     include(osx/osxbt.pri)
     SOURCES += \
diff --git a/src/bluetooth/osx/osxbtledeviceinquiry.mm b/src/bluetooth/osx/osxbtledeviceinquiry.mm
index 58cecccc..7f522c14 100644
--- a/src/bluetooth/osx/osxbtledeviceinquiry.mm
+++ b/src/bluetooth/osx/osxbtledeviceinquiry.mm
@@ -39,6 +39,7 @@
 
 #include "osxbtledeviceinquiry_p.h"
 #include "qbluetoothdeviceinfo.h"
+#include "osxbtnotifier_p.h"
 #include "qbluetoothuuid.h"
 #include "osxbtutility_p.h"
 
@@ -47,6 +48,8 @@
 
 #include "corebluetoothwrapper_p.h"
 
+#include <algorithm>
+
 QT_BEGIN_NAMESPACE
 
 namespace OSXBluetooth {
@@ -63,30 +66,35 @@ QBluetoothUuid qt_uuid(NSUUID *nsUuid)
     return QBluetoothUuid(qtUuidData);
 }
 
-}
+const int timeStepMS = 100;
 
+const int powerOffTimeoutMS = 30000;
+const qreal powerOffTimeStepS = 30. / 100.;
 
-QT_END_NAMESPACE
-
-#ifdef QT_NAMESPACE
+}
 
-using namespace QT_NAMESPACE;
+QT_END_NAMESPACE
 
-#endif
+QT_USE_NAMESPACE
 
 @interface QT_MANGLE_NAMESPACE(OSXBTLEDeviceInquiry) (PrivateAPI) <CBCentralManagerDelegate>
+// These two methods are scheduled with a small time step
+// within a given timeout, they either re-schedule
+// themselves or emit a signal/stop some operation.
 - (void)stopScan;
 - (void)handlePoweredOff;
 @end
 
 @implementation QT_MANGLE_NAMESPACE(OSXBTLEDeviceInquiry)
 
-- (id)init
+-(id)initWithNotifier:(LECBManagerNotifier *)aNotifier
 {
     if (self = [super init]) {
+        Q_ASSERT(aNotifier);
+        notifier = aNotifier;
         uuids.reset([[NSMutableSet alloc] init]);
         internalState = InquiryStarting;
-        state.store(int(internalState));
+        inquiryTimeoutMS = OSXBluetooth::defaultLEScanTimeoutMS;
     }
 
     return self;
@@ -100,27 +108,36 @@ using namespace QT_NAMESPACE;
             [manager stopScan];
     }
 
+    if (notifier) {
+        notifier->disconnect();
+        notifier->deleteLater();
+    }
+
     [super dealloc];
 }
 
 - (void)stopScan
 {
-    // Scan's "timeout" - we consider LE device
-    // discovery finished.
     using namespace OSXBluetooth;
 
+    // We never schedule stopScan if there is no timeout:
+    Q_ASSERT(inquiryTimeoutMS > 0);
+
     if (internalState == InquiryActive) {
-        if (scanTimer.elapsed() >= qt_LE_deviceInquiryLength() * 1000) {
-            // We indeed stop now:
+        const int elapsed = scanTimer.elapsed();
+        if (elapsed >= inquiryTimeoutMS) {
             [manager stopScan];
             [manager setDelegate:nil];
             internalState = InquiryFinished;
-            state.store(int(internalState));
+            Q_ASSERT(notifier);
+            emit notifier->discoveryFinished();
         } else {
+            // Re-schedule 'stopScan':
             dispatch_queue_t leQueue(qt_LE_queue());
             Q_ASSERT(leQueue);
+            const int timeChunkMS = std::min(inquiryTimeoutMS - elapsed, timeStepMS);
             dispatch_after(dispatch_time(DISPATCH_TIME_NOW,
-                                         int64_t(qt_LE_deviceInquiryLength() / 100. * NSEC_PER_SEC)),
+                                         int64_t(timeChunkMS / 1000. * NSEC_PER_SEC)),
                                          leQueue,
                                          ^{
                                                [self stopScan];
@@ -135,30 +152,32 @@ using namespace QT_NAMESPACE;
     // the system shows an alert asking to enable
     // Bluetooth in the 'Settings' app. If not done yet (after 30
     // seconds) - we consider it an error.
+    using namespace OSXBluetooth;
+
     if (internalState == InquiryStarting) {
-        if (errorTimer.elapsed() >= 30000) {
+        if (errorTimer.elapsed() >= powerOffTimeoutMS) {
             [manager setDelegate:nil];
             internalState = ErrorPoweredOff;
-            state.store(int(internalState));
+            Q_ASSERT(notifier);
+            emit notifier->CBManagerError(QBluetoothDeviceDiscoveryAgent::PoweredOffError);
         } else {
-            dispatch_queue_t leQueue(OSXBluetooth::qt_LE_queue());
+            dispatch_queue_t leQueue(qt_LE_queue());
             Q_ASSERT(leQueue);
             dispatch_after(dispatch_time(DISPATCH_TIME_NOW,
-                                         (int64_t)(30 / 100. * NSEC_PER_SEC)),
+                                         (int64_t)(powerOffTimeStepS * NSEC_PER_SEC)),
                                          leQueue,
                                          ^{
                                               [self handlePoweredOff];
                                           });
-
         }
     }
 }
 
-- (void)start
+- (void)startWithTimeout:(int)timeout
 {
     dispatch_queue_t leQueue(OSXBluetooth::qt_LE_queue());
-
     Q_ASSERT(leQueue);
+    inquiryTimeoutMS = timeout;
     manager.reset([[CBCentralManager alloc] initWithDelegate:self queue:leQueue]);
 }
 
@@ -170,6 +189,8 @@ using namespace QT_NAMESPACE;
     if (internalState != InquiryActive && internalState != InquiryStarting)
         return;
 
+    Q_ASSERT(notifier);
+
     using namespace OSXBluetooth;
 
     dispatch_queue_t leQueue(qt_LE_queue());
@@ -179,39 +200,50 @@ using namespace QT_NAMESPACE;
     if (cbState == CBCentralManagerStatePoweredOn) {
         if (internalState == InquiryStarting) {
             internalState = InquiryActive;
-            // Scan time is actually 10 seconds. Having a block with such delay can prevent
-            // 'self' from being deleted in time, which is not good. So we split this
-            // 10 s. timeout into smaller 'chunks'.
-            scanTimer.start();
-            dispatch_after(dispatch_time(DISPATCH_TIME_NOW,
-                                         int64_t(qt_LE_deviceInquiryLength() / 100. * NSEC_PER_SEC)),
-                                         leQueue,
-                                         ^{
-                                               [self stopScan];
-                                          });
+
+            if (inquiryTimeoutMS > 0) {
+                // We have a finite-length discovery, schedule stopScan,
+                // with a smaller time step, otherwise it can prevent
+                // 'self' from being deleted in time, which is not good
+                // (the block will retain 'self', waiting for timeout).
+                scanTimer.start();
+                const int timeChunkMS = std::min(timeStepMS, inquiryTimeoutMS);
+                dispatch_after(dispatch_time(DISPATCH_TIME_NOW,
+                                             int64_t(timeChunkMS / 1000. * NSEC_PER_SEC)),
+                                             leQueue,
+                                             ^{
+                                                   [self stopScan];
+                                              });
+            }
+
             [manager scanForPeripheralsWithServices:nil options:nil];
         } // Else we ignore.
-    } else if (state == CBCentralManagerStateUnsupported || state == CBCentralManagerStateUnauthorized) {
+    } else if (cbState == CBCentralManagerStateUnsupported
+               || cbState == CBCentralManagerStateUnauthorized) {
         if (internalState == InquiryActive) {
             [manager stopScan];
-            // Not sure how this is possible at all, probably, can never happen.
+            // Not sure how this is possible at all,
+            // probably, can never happen.
             internalState = ErrorPoweredOff;
+            emit notifier->CBManagerError(QBluetoothDeviceDiscoveryAgent::PoweredOffError);
         } else {
             internalState = ErrorLENotSupported;
+            emit notifier->LEnotSupported();
         }
 
         [manager setDelegate:nil];
     } else if (cbState == CBCentralManagerStatePoweredOff) {
         if (internalState == InquiryStarting) {
 #ifndef Q_OS_OSX
-            // On iOS a user can see at this point an alert asking to enable
-            // Bluetooth in the "Settings" app. If a user does,
+            // On iOS a user can see at this point an alert asking to
+            // enable Bluetooth in the "Settings" app. If a user does,
             // we'll receive 'PoweredOn' state update later.
-            // No change in state. Wait for 30 seconds (we split it into 'chunks' not
-            // to retain 'self' for too long ) ...
+            // No change in internalState. Wait for 30 seconds
+            // (we split it into smaller steps not to retain 'self' for
+            // too long ) ...
             errorTimer.start();
             dispatch_after(dispatch_time(DISPATCH_TIME_NOW,
-                                         (int64_t)(30 / 100. * NSEC_PER_SEC)),
+                                         (int64_t)(powerOffTimeStepS * NSEC_PER_SEC)),
                                          leQueue,
                                          ^{
                                               [self handlePoweredOff];
@@ -219,9 +251,10 @@ using namespace QT_NAMESPACE;
             return;
 #endif
             internalState = ErrorPoweredOff;
+            emit notifier->CBManagerError(QBluetoothDeviceDiscoveryAgent::PoweredOffError);
         } else {
-            internalState = ErrorPoweredOff;
             [manager stopScan];
+            emit notifier->CBManagerError(QBluetoothDeviceDiscoveryAgent::PoweredOffError);
         }
 
         [manager setDelegate:nil];
@@ -237,8 +270,6 @@ using namespace QT_NAMESPACE;
         // lost; an update is imminent. "
         // Wait for this imminent update.
     }
-
-    state.store(int(internalState));
 }
 
 - (void)stop
@@ -248,11 +279,16 @@ using namespace QT_NAMESPACE;
 
     [manager setDelegate:nil];
     internalState = InquiryCancelled;
-    state.store(int(internalState));
+
+    notifier->disconnect();
+    notifier->deleteLater();
+    notifier = nullptr;
 }
 
-- (void)centralManager:(CBCentralManager *)central didDiscoverPeripheral:(CBPeripheral *)peripheral
-        advertisementData:(NSDictionary *)advertisementData RSSI:(NSNumber *)RSSI
+- (void)centralManager:(CBCentralManager *)central
+        didDiscoverPeripheral:(CBPeripheral *)peripheral
+        advertisementData:(NSDictionary *)advertisementData
+        RSSI:(NSNumber *)RSSI
 {
     Q_UNUSED(advertisementData);
 
@@ -264,9 +300,10 @@ using namespace QT_NAMESPACE;
     if (internalState != InquiryActive)
         return;
 
-    QBluetoothUuid deviceUuid;
-
+    if (!notifier)
+        return;
 
+    QBluetoothUuid deviceUuid;
 
     if (!peripheral.identifier) {
         qCWarning(QT_BT_OSX) << "peripheral without NSUUID";
@@ -274,7 +311,9 @@ using namespace QT_NAMESPACE;
     }
 
     if ([uuids containsObject:peripheral.identifier]) {
-        // We already know this peripheral ...
+        // TODO: my understanding of the same peripheral reported many times seems
+        // to be outdated or even wrong - nowadays it's reported twice and the
+        // second time (AFAIK) more info can be extracted ...
         return;
     }
 
@@ -296,17 +335,7 @@ using namespace QT_NAMESPACE;
         newDeviceInfo.setRssi([RSSI shortValue]);
     // CoreBluetooth scans only for LE devices.
     newDeviceInfo.setCoreConfigurations(QBluetoothDeviceInfo::LowEnergyCoreConfiguration);
-    devices.append(newDeviceInfo);
-}
-
-- (LEInquiryState) inquiryState
-{
-    return LEInquiryState(state.load());
-}
-
-- (const QList<QBluetoothDeviceInfo> &)discoveredDevices
-{
-    return devices;
+    emit notifier->deviceDiscovered(newDeviceInfo);
 }
 
 @end
diff --git a/src/bluetooth/osx/osxbtledeviceinquiry_p.h b/src/bluetooth/osx/osxbtledeviceinquiry_p.h
index 24bf181e..d79272be 100644
--- a/src/bluetooth/osx/osxbtledeviceinquiry_p.h
+++ b/src/bluetooth/osx/osxbtledeviceinquiry_p.h
@@ -57,7 +57,6 @@
 
 #include <QtCore/qelapsedtimer.h>
 #include <QtCore/qglobal.h>
-#include <QtCore/qatomic.h>
 #include <QtCore/qlist.h>
 
 #include <Foundation/Foundation.h>
@@ -69,8 +68,20 @@ QT_BEGIN_NAMESPACE
 
 class QBluetoothUuid;
 
+namespace OSXBluetooth
+{
+
+class LECBManagerNotifier;
+
+}
+
 QT_END_NAMESPACE
 
+// Ugly but all these QT_PREPEND_NAMESPACE etc. are even worse ...
+using OSXBluetooth::LECBManagerNotifier;
+using OSXBluetooth::ObjCScopedPointer;
+using QT_PREPEND_NAMESPACE(QElapsedTimer);
+
 enum LEInquiryState
 {
     InquiryStarting,
@@ -83,29 +94,27 @@ enum LEInquiryState
 
 @interface QT_MANGLE_NAMESPACE(OSXBTLEDeviceInquiry) : NSObject
 {
-    QT_PREPEND_NAMESPACE(OSXBluetooth)::ObjCScopedPointer<NSMutableSet> uuids;
-    QT_PREPEND_NAMESPACE(OSXBluetooth)::ObjCScopedPointer<CBCentralManager> manager;
+    LECBManagerNotifier *notifier;
+    ObjCScopedPointer<NSMutableSet> uuids;
+    ObjCScopedPointer<CBCentralManager> manager;
 
     QList<QBluetoothDeviceInfo> devices;
-
     LEInquiryState internalState;
-    QT_PREPEND_NAMESPACE(QAtomicInt) state;
+    int inquiryTimeoutMS;
 
     // Timers to check if we can execute delayed callbacks:
     QT_PREPEND_NAMESPACE(QElapsedTimer) errorTimer;
     QT_PREPEND_NAMESPACE(QElapsedTimer) scanTimer;
 }
 
-- (id)init;
+- (id)initWithNotifier:(LECBManagerNotifier *)aNotifier;
 - (void)dealloc;
 
-// IMPORTANT: both 'start' and 'stop' are to be executed on the "Qt's LE queue".
-- (void)start;
+// IMPORTANT: both 'startWithTimeout' and 'stop'
+// can be executed only on the "Qt's LE queue".
+- (void)startWithTimeout:(int)timeout;
 - (void)stop;
 
-- (LEInquiryState)inquiryState;
-- (const QList<QBluetoothDeviceInfo> &)discoveredDevices;
-
 @end
 
 #endif
diff --git a/src/bluetooth/osx/osxbtnotifier_p.h b/src/bluetooth/osx/osxbtnotifier_p.h
index 3059e2d3..0ffd7f51 100644
--- a/src/bluetooth/osx/osxbtnotifier_p.h
+++ b/src/bluetooth/osx/osxbtnotifier_p.h
@@ -52,7 +52,9 @@
 //
 
 
+#include "qbluetoothdevicediscoveryagent.h"
 #include "qlowenergycontroller.h"
+#include "qbluetoothdeviceinfo.h"
 #include "qbluetoothuuid.h"
 #include "qbluetooth.h"
 
@@ -73,6 +75,9 @@ class LECBManagerNotifier : public QObject
     Q_OBJECT
 
 Q_SIGNALS:
+    void deviceDiscovered(QBluetoothDeviceInfo deviceInfo);
+    void discoveryFinished();
+
     void connected();
     void disconnected();
 
@@ -85,6 +90,7 @@ Q_SIGNALS:
     void descriptorWritten(QLowEnergyHandle descHandle, const QByteArray &value);
 
     void LEnotSupported();
+    void CBManagerError(QBluetoothDeviceDiscoveryAgent::Error error);
     void CBManagerError(QLowEnergyController::Error error);
     void CBManagerError(const QBluetoothUuid &serviceUuid, QLowEnergyController::Error error);
     void CBManagerError(const QBluetoothUuid &serviceUuid, QLowEnergyService::ServiceError error);
diff --git a/src/bluetooth/osx/osxbtutility.mm b/src/bluetooth/osx/osxbtutility.mm
index f579b2a4..29159cdb 100644
--- a/src/bluetooth/osx/osxbtutility.mm
+++ b/src/bluetooth/osx/osxbtutility.mm
@@ -68,6 +68,8 @@ Q_LOGGING_CATEGORY(QT_BT_OSX, "qt.bluetooth.ios")
 
 namespace OSXBluetooth {
 
+const int defaultLEScanTimeoutMS = 25000;
+
 QString qt_address(NSString *address)
 {
     if (address && address.length) {
@@ -348,11 +350,6 @@ dispatch_queue_t qt_LE_queue()
     return leQueue.data();
 }
 
-unsigned qt_LE_deviceInquiryLength()
-{
-    return 10;
-}
-
 }
 
 QT_END_NAMESPACE
diff --git a/src/bluetooth/osx/osxbtutility_p.h b/src/bluetooth/osx/osxbtutility_p.h
index 5e616b74..28ecfec9 100644
--- a/src/bluetooth/osx/osxbtutility_p.h
+++ b/src/bluetooth/osx/osxbtutility_p.h
@@ -53,7 +53,6 @@
 
 #include <QtCore/qloggingcategory.h>
 #include <QtCore/qscopedpointer.h>
-#include <QtCore/qsysinfo.h>
 #include <QtCore/qglobal.h>
 
 #include <Foundation/Foundation.h>
@@ -302,20 +301,9 @@ QByteArray qt_bytearray(NSData *data);
 QByteArray qt_bytearray(NSObject *data);
 ObjCStrongReference<NSData> data_from_bytearray(const QByteArray & qtData);
 
-inline QSysInfo::MacVersion qt_OS_limit(QSysInfo::MacVersion osxVersion, QSysInfo::MacVersion iosVersion)
-{
-#ifdef Q_OS_OSX
-    Q_UNUSED(iosVersion)
-    return osxVersion;
-#else
-    Q_UNUSED(osxVersion)
-    return iosVersion;
-#endif
-}
-
 dispatch_queue_t qt_LE_queue();
-// LE scan, in seconds.
-unsigned qt_LE_deviceInquiryLength();
+
+extern const int defaultLEScanTimeoutMS;
 
 } // namespace OSXBluetooth
 
diff --git a/src/bluetooth/qbluetoothdevicediscoveryagent_ios.mm b/src/bluetooth/qbluetoothdevicediscoveryagent_ios.mm
index 571eb793..f2611602 100644
--- a/src/bluetooth/qbluetoothdevicediscoveryagent_ios.mm
+++ b/src/bluetooth/qbluetoothdevicediscoveryagent_ios.mm
@@ -37,16 +37,17 @@
 **
 ****************************************************************************/
 
-#include "qbluetoothdevicediscoverytimer_osx_p.h"
 #include "qbluetoothdevicediscoveryagent.h"
 #include "osx/osxbtledeviceinquiry_p.h"
 #include "qbluetoothlocaldevice.h"
 #include "qbluetoothdeviceinfo.h"
+#include "osx/osxbtnotifier_p.h"
 #include "osx/osxbtutility_p.h"
 #include "osx/uistrings_p.h"
 #include "qbluetoothuuid.h"
 
 #include <QtCore/qloggingcategory.h>
+#include <QtCore/qobject.h>
 #include <QtCore/qglobal.h>
 #include <QtCore/qstring.h>
 #include <QtCore/qdebug.h>
@@ -56,12 +57,24 @@
 
 QT_BEGIN_NAMESPACE
 
-using OSXBluetooth::ObjCScopedPointer;
+namespace
+{
+
+void registerQDeviceDiscoveryMetaType()
+{
+    static bool initDone = false;
+    if (!initDone) {
+        qRegisterMetaType<QBluetoothDeviceInfo>();
+        qRegisterMetaType<QBluetoothDeviceDiscoveryAgent::Error>();
+        initDone = true;
+    }
+}
+
+}//namespace
 
-class QBluetoothDeviceDiscoveryAgentPrivate
+class QBluetoothDeviceDiscoveryAgentPrivate : public QObject
 {
     friend class QBluetoothDeviceDiscoveryAgent;
-    friend class OSXBluetooth::DDATimerHandler;
 
 public:
     QBluetoothDeviceDiscoveryAgentPrivate(const QBluetoothAddress &address,
@@ -74,13 +87,12 @@ public:
     void stop();
 
 private:
-    typedef QT_MANGLE_NAMESPACE(OSXBTLEDeviceInquiry) LEDeviceInquiryObjC;
+    using LEDeviceInquiryObjC = QT_MANGLE_NAMESPACE(OSXBTLEDeviceInquiry);
 
     void LEinquiryError(QBluetoothDeviceDiscoveryAgent::Error error);
     void LEnotSupported();
     void LEdeviceFound(const QBluetoothDeviceInfo &info);
     void LEinquiryFinished();
-    void checkLETimeout();
 
     void setError(QBluetoothDeviceDiscoveryAgent::Error, const QString &text = QString());
 
@@ -91,54 +103,18 @@ private:
 
     QBluetoothDeviceDiscoveryAgent::InquiryType inquiryType;
 
-    typedef ObjCScopedPointer<LEDeviceInquiryObjC> LEDeviceInquiry;
+    using LEDeviceInquiry = OSXBluetooth::ObjCScopedPointer<LEDeviceInquiryObjC>;
     LEDeviceInquiry inquiryLE;
 
-    typedef QList<QBluetoothDeviceInfo> DevicesList;
+    using DevicesList = QList<QBluetoothDeviceInfo>;
     DevicesList discoveredDevices;
 
     bool startPending;
     bool stopPending;
 
-    QScopedPointer<OSXBluetooth::DDATimerHandler> timer;
     int lowEnergySearchTimeout;
 };
 
-namespace OSXBluetooth {
-
-DDATimerHandler::DDATimerHandler(QBluetoothDeviceDiscoveryAgentPrivate *d)
-    : owner(d)
-{
-    Q_ASSERT_X(owner, Q_FUNC_INFO, "invalid pointer");
-
-    timer.setSingleShot(false);
-    connect(&timer, &QTimer::timeout, this, &DDATimerHandler::onTimer);
-}
-
-void DDATimerHandler::start(int msec)
-{
-    Q_ASSERT_X(msec > 0, Q_FUNC_INFO, "invalid time interval");
-    if (timer.isActive()) {
-        qCWarning(QT_BT_OSX) << Q_FUNC_INFO << "timer is active";
-        return;
-    }
-
-    timer.start(msec);
-}
-
-void DDATimerHandler::stop()
-{
-    timer.stop();
-}
-
-void DDATimerHandler::onTimer()
-{
-    Q_ASSERT(owner);
-    owner->checkLETimeout();
-}
-
-}
-
 QBluetoothDeviceDiscoveryAgentPrivate::QBluetoothDeviceDiscoveryAgentPrivate(const QBluetoothAddress &adapter,
                                                                              QBluetoothDeviceDiscoveryAgent *q) :
     q_ptr(q),
@@ -146,10 +122,11 @@ QBluetoothDeviceDiscoveryAgentPrivate::QBluetoothDeviceDiscoveryAgentPrivate(con
     inquiryType(QBluetoothDeviceDiscoveryAgent::GeneralUnlimitedInquiry),
     startPending(false),
     stopPending(false),
-    lowEnergySearchTimeout(-1) // change when implemented
+    lowEnergySearchTimeout(OSXBluetooth::defaultLEScanTimeoutMS)
 {
     Q_UNUSED(adapter);
 
+    registerQDeviceDiscoveryMetaType();
     Q_ASSERT_X(q != Q_NULLPTR, Q_FUNC_INFO, "invalid q_ptr (null)");
 }
 
@@ -160,7 +137,7 @@ QBluetoothDeviceDiscoveryAgentPrivate::~QBluetoothDeviceDiscoveryAgentPrivate()
         if (dispatch_queue_t leQueue = OSXBluetooth::qt_LE_queue()) {
             // Local variable to be retained ...
             LEDeviceInquiryObjC *inq = inquiryLE.data();
-            dispatch_async(leQueue, ^{
+            dispatch_sync(leQueue, ^{
                 [inq stop];
             });
         }
@@ -188,26 +165,37 @@ void QBluetoothDeviceDiscoveryAgentPrivate::start()
 
     using namespace OSXBluetooth;
 
-    inquiryLE.reset([[LEDeviceInquiryObjC alloc] init]);
+    QScopedPointer<LECBManagerNotifier> notifier(new LECBManagerNotifier);
+    // Connections:
+    using ErrMemFunPtr = void (LECBManagerNotifier::*)(QBluetoothDeviceDiscoveryAgent::Error);
+    notifier->connect(notifier.data(), ErrMemFunPtr(&LECBManagerNotifier::CBManagerError),
+                      this, &QBluetoothDeviceDiscoveryAgentPrivate::LEinquiryError);
+    notifier->connect(notifier.data(), &LECBManagerNotifier::LEnotSupported,
+                      this, &QBluetoothDeviceDiscoveryAgentPrivate::LEnotSupported);
+    notifier->connect(notifier.data(), &LECBManagerNotifier::discoveryFinished,
+                      this, &QBluetoothDeviceDiscoveryAgentPrivate::LEinquiryFinished);
+    notifier->connect(notifier.data(), &LECBManagerNotifier::deviceDiscovered,
+                      this, &QBluetoothDeviceDiscoveryAgentPrivate::LEdeviceFound);
+
+    inquiryLE.reset([[LEDeviceInquiryObjC alloc] initWithNotifier:notifier.data()]);
+    if (inquiryLE)
+        notifier.take(); // Whatever happens next, inquiryLE is already the owner ...
+
     dispatch_queue_t leQueue(qt_LE_queue());
     if (!leQueue || !inquiryLE) {
         setError(QBluetoothDeviceDiscoveryAgent::UnknownError,
                  QCoreApplication::translate(DEV_DISCOVERY, DD_NOT_STARTED));
         emit q_ptr->error(lastError);
+        return;
     }
 
     discoveredDevices.clear();
     setError(QBluetoothDeviceDiscoveryAgent::NoError);
 
-    // CoreBluetooth does not have a timeout. We start a timer here
-    // and check if scan really started and if yes if we have a timeout.
-    timer.reset(new OSXBluetooth::DDATimerHandler(this));
-    timer->start(2000);
-
     // Create a local variable - to have a strong referece in a block.
     LEDeviceInquiryObjC *inq = inquiryLE.data();
     dispatch_async(leQueue, ^{
-        [inq start];
+        [inq startWithTimeout:lowEnergySearchTimeout];
     });
 }
 
@@ -225,7 +213,7 @@ void QBluetoothDeviceDiscoveryAgentPrivate::stop()
 
     // Create a local variable - to have a strong referece in a block.
     LEDeviceInquiryObjC *inq = inquiryLE.data();
-    dispatch_async(leQueue, ^{
+    dispatch_sync(leQueue, ^{
         [inq stop];
     });
     // We consider LE scan to be stopped immediately and
@@ -243,7 +231,6 @@ void QBluetoothDeviceDiscoveryAgentPrivate::LEinquiryError(QBluetoothDeviceDisco
                Q_FUNC_INFO, "unexpected error");
 
     inquiryLE.reset();
-    timer->stop();
 
     startPending = false;
     stopPending = false;
@@ -254,7 +241,6 @@ void QBluetoothDeviceDiscoveryAgentPrivate::LEinquiryError(QBluetoothDeviceDisco
 void QBluetoothDeviceDiscoveryAgentPrivate::LEnotSupported()
 {
     inquiryLE.reset();
-    timer->stop();
 
     startPending = false;
     stopPending = false;
@@ -283,7 +269,6 @@ void QBluetoothDeviceDiscoveryAgentPrivate::LEdeviceFound(const QBluetoothDevice
 void QBluetoothDeviceDiscoveryAgentPrivate::LEinquiryFinished()
 {
     inquiryLE.reset();
-    timer->stop();
 
     if (stopPending && !startPending) {
         stopPending = false;
@@ -297,41 +282,6 @@ void QBluetoothDeviceDiscoveryAgentPrivate::LEinquiryFinished()
     }
 }
 
-void QBluetoothDeviceDiscoveryAgentPrivate::checkLETimeout()
-{
-    Q_ASSERT_X(inquiryLE, Q_FUNC_INFO, "LE device inquiry is nil");
-
-    using namespace OSXBluetooth;
-
-    const LEInquiryState state([inquiryLE inquiryState]);
-    if (state == InquiryStarting || state == InquiryActive)
-        return; // Wait ...
-
-    if (state == ErrorPoweredOff)
-        return LEinquiryError(QBluetoothDeviceDiscoveryAgent::PoweredOffError);
-
-    if (state == ErrorLENotSupported)
-        return LEnotSupported();
-
-    if (state == InquiryFinished) {
-        // Process found devices if any ...
-        const QList<QBluetoothDeviceInfo> leDevices([inquiryLE discoveredDevices]);
-        foreach (const QBluetoothDeviceInfo &info, leDevices) {
-            // We were cancelled on a previous device discovered signal ...
-            if (!inquiryLE)
-                break;
-            LEdeviceFound(info);
-        }
-
-        if (inquiryLE)
-            LEinquiryFinished();
-        return;
-    }
-
-    qCWarning(QT_BT_OSX) << Q_FUNC_INFO << "unexpected inquiry state in LE timeout";
-    // Actually, this deserves an assert :)
-}
-
 void QBluetoothDeviceDiscoveryAgentPrivate::setError(QBluetoothDeviceDiscoveryAgent::Error error,
                                                      const QString &text)
 {
@@ -375,7 +325,7 @@ QBluetoothDeviceDiscoveryAgent::QBluetoothDeviceDiscoveryAgent(
     d_ptr(new QBluetoothDeviceDiscoveryAgentPrivate(deviceAdapter, this))
 {
     if (!deviceAdapter.isNull()) {
-        qCWarning(QT_BT_OSX) << Q_FUNC_INFO << "local device address is "
+        qCWarning(QT_BT_OSX) << "local device address is "
                                 "not available, provided address is ignored";
         d_ptr->setError(InvalidBluetoothAdapterError);
     }
@@ -407,7 +357,7 @@ void QBluetoothDeviceDiscoveryAgent::start()
         if (!isActive())
             d_ptr->start();
         else
-            qCDebug(QT_BT_OSX) << Q_FUNC_INFO << "already started";
+            qCDebug(QT_BT_OSX) << "already started";
     }
 }
 
diff --git a/src/bluetooth/qbluetoothdevicediscoveryagent_osx.mm b/src/bluetooth/qbluetoothdevicediscoveryagent_osx.mm
index 5422d235..eedeebb5 100644
--- a/src/bluetooth/qbluetoothdevicediscoveryagent_osx.mm
+++ b/src/bluetooth/qbluetoothdevicediscoveryagent_osx.mm
@@ -37,21 +37,21 @@
 **
 ****************************************************************************/
 
-#include "qbluetoothdevicediscoverytimer_osx_p.h"
 #include "qbluetoothdevicediscoveryagent.h"
 #include "osx/osxbtledeviceinquiry_p.h"
 #include "osx/osxbtdeviceinquiry_p.h"
 #include "qbluetoothlocaldevice.h"
 #include "osx/osxbtsdpinquiry_p.h"
 #include "qbluetoothdeviceinfo.h"
+#include "osx/osxbtnotifier_p.h"
 #include "osx/osxbtutility_p.h"
-#include "osx/uistrings_p.h"
 #include "qbluetoothhostinfo.h"
+#include "qbluetoothaddress.h"
+#include "osx/uistrings_p.h"
 #include "qbluetoothuuid.h"
 
 #include <QtCore/qloggingcategory.h>
 #include <QtCore/qscopedpointer.h>
-#include <QtCore/qdatetime.h>
 #include <QtCore/qglobal.h>
 #include <QtCore/qstring.h>
 #include <QtCore/qdebug.h>
@@ -63,18 +63,34 @@
 
 QT_BEGIN_NAMESPACE
 
-using OSXBluetooth::ObjCScopedPointer;
+namespace
+{
 
-class QBluetoothDeviceDiscoveryAgentPrivate : public OSXBluetooth::DeviceInquiryDelegate
+void registerQDeviceDiscoveryMetaType()
+{
+    static bool initDone = false;
+    if (!initDone) {
+        qRegisterMetaType<QBluetoothDeviceInfo>();
+        qRegisterMetaType<QBluetoothDeviceDiscoveryAgent::Error>();
+        initDone = true;
+    }
+}
+
+}//namespace
+
+class QBluetoothDeviceDiscoveryAgentPrivate : public QObject,
+                                              public OSXBluetooth::DeviceInquiryDelegate
 {
     friend class QBluetoothDeviceDiscoveryAgent;
-    friend class OSXBluetooth::DDATimerHandler;
 public:
-    typedef QT_MANGLE_NAMESPACE(OSXBTLEDeviceInquiry) LEDeviceInquiryObjC;
+    template<class T>
+    using ObjCScopedPointer = OSXBluetooth::ObjCScopedPointer<T>;
+    using LEDeviceInquiryObjC = QT_MANGLE_NAMESPACE(OSXBTLEDeviceInquiry);
 
     QBluetoothDeviceDiscoveryAgentPrivate(const QBluetoothAddress & address,
                                           QBluetoothDeviceDiscoveryAgent *q);
-    virtual ~QBluetoothDeviceDiscoveryAgentPrivate();
+
+    ~QBluetoothDeviceDiscoveryAgentPrivate() Q_DECL_OVERRIDE;
 
     bool isValid() const;
     bool isActive() const;
@@ -95,7 +111,6 @@ private:
     void error(IOBluetoothDeviceInquiry *inq, IOReturn error) Q_DECL_OVERRIDE;
     void deviceFound(IOBluetoothDeviceInquiry *inq, IOBluetoothDevice *device) Q_DECL_OVERRIDE;
 
-    //
     void LEinquiryFinished();
     void LEinquiryError(QBluetoothDeviceDiscoveryAgent::Error error);
     void LEnotSupported();
@@ -105,9 +120,8 @@ private:
     void deviceFound(const QBluetoothDeviceInfo &newDeviceInfo);
 
     void setError(IOReturn error, const QString &text = QString());
-    void setError(QBluetoothDeviceDiscoveryAgent::Error, const QString &text = QString());
-
-    void checkLETimeout();
+    void setError(QBluetoothDeviceDiscoveryAgent::Error,
+                  const QString &text = QString());
 
     QBluetoothDeviceDiscoveryAgent *q_ptr;
     AgentState agentState;
@@ -122,57 +136,21 @@ private:
 
     QBluetoothDeviceDiscoveryAgent::InquiryType inquiryType;
 
-    typedef ObjCScopedPointer<DeviceInquiryObjC> DeviceInquiry;
+    using DeviceInquiry = ObjCScopedPointer<DeviceInquiryObjC>;
     DeviceInquiry inquiry;
 
-    typedef ObjCScopedPointer<LEDeviceInquiryObjC> LEDeviceInquiry;
+    using LEDeviceInquiry = ObjCScopedPointer<LEDeviceInquiryObjC>;
     LEDeviceInquiry inquiryLE;
 
-    typedef ObjCScopedPointer<IOBluetoothHostController> HostController;
+    using HostController = ObjCScopedPointer<IOBluetoothHostController>;
     HostController hostController;
 
-    typedef QList<QBluetoothDeviceInfo> DevicesList;
+    using DevicesList = QList<QBluetoothDeviceInfo>;
     DevicesList discoveredDevices;
 
-    QScopedPointer<OSXBluetooth::DDATimerHandler> timer;
     int lowEnergySearchTimeout;
 };
 
-namespace OSXBluetooth {
-
-DDATimerHandler::DDATimerHandler(QBluetoothDeviceDiscoveryAgentPrivate *d)
-    : owner(d)
-{
-    Q_ASSERT_X(owner, Q_FUNC_INFO, "invalid pointer");
-
-    timer.setSingleShot(false);
-    connect(&timer, &QTimer::timeout, this, &DDATimerHandler::onTimer);
-}
-
-void DDATimerHandler::start(int msec)
-{
-    Q_ASSERT_X(msec > 0, Q_FUNC_INFO, "invalid time interval");
-    if (timer.isActive()) {
-        qCWarning(QT_BT_OSX) << "timer is active";
-        return;
-    }
-
-    timer.start(msec);
-}
-
-void DDATimerHandler::stop()
-{
-    timer.stop();
-}
-
-void DDATimerHandler::onTimer()
-{
-    Q_ASSERT(owner);
-    owner->checkLETimeout();
-}
-
-}
-
 QBluetoothDeviceDiscoveryAgentPrivate::QBluetoothDeviceDiscoveryAgentPrivate(const QBluetoothAddress &adapter,
                                                                              QBluetoothDeviceDiscoveryAgent *q) :
     q_ptr(q),
@@ -182,8 +160,10 @@ QBluetoothDeviceDiscoveryAgentPrivate::QBluetoothDeviceDiscoveryAgentPrivate(con
     stopPending(false),
     lastError(QBluetoothDeviceDiscoveryAgent::NoError),
     inquiryType(QBluetoothDeviceDiscoveryAgent::GeneralUnlimitedInquiry),
-    lowEnergySearchTimeout(-1) // change when implemented
+    lowEnergySearchTimeout(OSXBluetooth::defaultLEScanTimeoutMS)
 {
+    registerQDeviceDiscoveryMetaType();
+
     Q_ASSERT_X(q != Q_NULLPTR, Q_FUNC_INFO, "invalid q_ptr (null)");
 
     HostController controller([[IOBluetoothHostController defaultController] retain]);
@@ -209,7 +189,7 @@ QBluetoothDeviceDiscoveryAgentPrivate::~QBluetoothDeviceDiscoveryAgentPrivate()
         if (dispatch_queue_t leQueue = OSXBluetooth::qt_LE_queue()) {
             // Local variable to be retained ...
             LEDeviceInquiryObjC *inq = inquiryLE.data();
-            dispatch_async(leQueue, ^{
+            dispatch_sync(leQueue, ^{
                 [inq stop];
             });
         }
@@ -270,7 +250,23 @@ void QBluetoothDeviceDiscoveryAgentPrivate::startLE()
 
     using namespace OSXBluetooth;
 
-    inquiryLE.reset([[LEDeviceInquiryObjC alloc] init]);
+    QScopedPointer<LECBManagerNotifier> notifier(new LECBManagerNotifier);
+    // Connections:
+    using ErrMemFunPtr = void (LECBManagerNotifier::*)(QBluetoothDeviceDiscoveryAgent::Error);
+    notifier->connect(notifier.data(), ErrMemFunPtr(&LECBManagerNotifier::CBManagerError),
+                      this, &QBluetoothDeviceDiscoveryAgentPrivate::LEinquiryError);
+    notifier->connect(notifier.data(), &LECBManagerNotifier::LEnotSupported,
+                      this, &QBluetoothDeviceDiscoveryAgentPrivate::LEnotSupported);
+    notifier->connect(notifier.data(), &LECBManagerNotifier::discoveryFinished,
+                      this, &QBluetoothDeviceDiscoveryAgentPrivate::LEinquiryFinished);
+    using DeviceMemFunPtr = void (QBluetoothDeviceDiscoveryAgentPrivate::*)(const QBluetoothDeviceInfo &);
+    notifier->connect(notifier.data(), &LECBManagerNotifier::deviceDiscovered,
+                      this, DeviceMemFunPtr(&QBluetoothDeviceDiscoveryAgentPrivate::deviceFound));
+
+    // Check queue and create scanner:
+    inquiryLE.reset([[LEDeviceInquiryObjC alloc] initWithNotifier:notifier.data()]);
+    if (inquiryLE)
+        notifier.take(); // Whatever happens next, inquiryLE is already the owner ...
 
     dispatch_queue_t leQueue(qt_LE_queue());
     if (!leQueue || !inquiryLE) {
@@ -278,18 +274,15 @@ void QBluetoothDeviceDiscoveryAgentPrivate::startLE()
                  QCoreApplication::translate(DEV_DISCOVERY, DD_NOT_STARTED_LE));
         agentState = NonActive;
         emit q_ptr->error(lastError);
+        return;
     }
 
+    // Now start in on LE queue:
     agentState = LEScan;
-    // CoreBluetooth does not have a timeout. We start a timer here
-    // and check if scan is active/finished/finished with error(s).
-    timer.reset(new OSXBluetooth::DDATimerHandler(this));
-    timer->start(2000);
-
     // We need the local variable so that it's retained ...
     LEDeviceInquiryObjC *inq = inquiryLE.data();
     dispatch_async(leQueue, ^{
-        [inq start];
+        [inq startWithTimeout:lowEnergySearchTimeout];
     });
 }
 
@@ -322,7 +315,7 @@ void QBluetoothDeviceDiscoveryAgentPrivate::stop()
         Q_ASSERT(leQueue);
         // We need the local variable so that it's retained ...
         LEDeviceInquiryObjC *inq = inquiryLE.data();
-        dispatch_async(leQueue, ^{
+        dispatch_sync(leQueue, ^{
             [inq stop];
         });
         // We consider LE scan to be stopped immediately and
@@ -446,49 +439,16 @@ void QBluetoothDeviceDiscoveryAgentPrivate::setError(QBluetoothDeviceDiscoveryAg
         qCDebug(QT_BT_OSX) << "error set: "<<errorString;
 }
 
-void QBluetoothDeviceDiscoveryAgentPrivate::checkLETimeout()
-{
-    Q_ASSERT_X(agentState == LEScan, Q_FUNC_INFO, "invalid agent state");
-    Q_ASSERT_X(inquiryLE, Q_FUNC_INFO, "LE device inquiry is nil");
-
-    using namespace OSXBluetooth;
-
-    const LEInquiryState state([inquiryLE inquiryState]);
-    if (state == InquiryStarting || state == InquiryActive)
-        return; // Wait ...
-
-    if (state == ErrorPoweredOff)
-        return LEinquiryError(QBluetoothDeviceDiscoveryAgent::PoweredOffError);
-
-    if (state == ErrorLENotSupported)
-        return LEnotSupported();
-
-    if (state == InquiryFinished) {
-        // Process found devices if any ...
-        const QList<QBluetoothDeviceInfo> leDevices([inquiryLE discoveredDevices]);
-        foreach (const QBluetoothDeviceInfo &info, leDevices) {
-            // We were cancelled on a previous device discovered signal ...
-            if (agentState != LEScan)
-                break;
-            deviceFound(info);
-        }
-
-        if (agentState == LEScan)
-            LEinquiryFinished();
-        return;
-    }
-
-    qCWarning(QT_BT_OSX) << "unexpected inquiry state in LE timeout";
-}
-
 void QBluetoothDeviceDiscoveryAgentPrivate::LEinquiryError(QBluetoothDeviceDiscoveryAgent::Error error)
 {
     // At the moment the only error reported can be 'powered off' error, it happens
     // after the LE scan started (so we have LE support and this is a real PoweredOffError).
     Q_ASSERT(error == QBluetoothDeviceDiscoveryAgent::PoweredOffError);
 
-    timer->stop();
     inquiryLE.reset();
+
+    startPending = false;
+    stopPending = false;
     agentState = NonActive;
     setError(error);
     emit q_ptr->error(lastError);
@@ -506,7 +466,6 @@ void QBluetoothDeviceDiscoveryAgentPrivate::LEinquiryFinished()
     // The same logic as in inquiryFinished, but does not start LE scan.
     agentState = NonActive;
     inquiryLE.reset();
-    timer->stop();
 
     if (stopPending && !startPending) {
         stopPending = false;
diff --git a/src/bluetooth/qbluetoothdevicediscoverytimer_osx_p.h b/src/bluetooth/qbluetoothdevicediscoverytimer_osx_p.h
deleted file mode 100644
index 88906ffd..00000000
--- a/src/bluetooth/qbluetoothdevicediscoverytimer_osx_p.h
+++ /dev/null
@@ -1,85 +0,0 @@
-/****************************************************************************
-**
-** Copyright (C) 2016 The Qt Company Ltd.
-** Contact: https://www.qt.io/licensing/
-**
-** This file is part of the QtBluetooth module of the Qt Toolkit.
-**
-** $QT_BEGIN_LICENSE:LGPL$
-** 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 The Qt Company. For licensing terms
-** and conditions see https://www.qt.io/terms-conditions. For further
-** information use the contact form at https://www.qt.io/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 3 as published by the Free Software
-** Foundation and appearing in the file LICENSE.LGPL3 included in the
-** packaging of this file. Please review the following information to
-** ensure the GNU Lesser General Public License version 3 requirements
-** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
-**
-** GNU General Public License Usage
-** Alternatively, this file may be used under the terms of the GNU
-** General Public License version 2.0 or (at your option) the GNU General
-** Public license version 3 or any later version approved by the KDE Free
-** Qt Foundation. The licenses are as published by the Free Software
-** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
-** included in the packaging of this file. Please review the following
-** information to ensure the GNU General Public License requirements will
-** be met: https://www.gnu.org/licenses/gpl-2.0.html and
-** https://www.gnu.org/licenses/gpl-3.0.html.
-**
-** $QT_END_LICENSE$
-**
-****************************************************************************/
-
-#ifndef QBLUETOOTHDEVICEDISCOVERYTIMER_OSX_P_H
-#define QBLUETOOTHDEVICEDISCOVERYTIMER_OSX_P_H
-
-//
-//  W A R N I N G
-//  -------------
-//
-// This file is not part of the Qt API.  It exists purely as an
-// implementation detail.  This header file may change from version to
-// version without notice, or even be removed.
-//
-// We mean it.
-//
-
-#include <QtCore/qglobal.h>
-#include <QtCore/qtimer.h>
-
-QT_BEGIN_NAMESPACE
-
-class QBluetoothDeviceDiscoveryAgentPrivate;
-
-namespace OSXBluetooth {
-
-class DDATimerHandler : public QObject
-{
-    Q_OBJECT
-
-public:
-    DDATimerHandler(QBluetoothDeviceDiscoveryAgentPrivate *d);
-
-    void start(int msec);
-    void stop();
-
-private slots:
-    void onTimer();
-
-private:
-    QTimer timer;
-    QBluetoothDeviceDiscoveryAgentPrivate *owner;
-};
-
-}
-
-QT_END_NAMESPACE
-
-#endif // QBLUETOOTHDEVICEDISCOVERYTIMER_OSX_P_H
diff --git a/src/bluetooth/qlowenergycontroller_osx.mm b/src/bluetooth/qlowenergycontroller_osx.mm
index 5c4c7c37..6e85e630 100644
--- a/src/bluetooth/qlowenergycontroller_osx.mm
+++ b/src/bluetooth/qlowenergycontroller_osx.mm
@@ -103,7 +103,6 @@ ServicePrivate qt_createLEService(QLowEnergyControllerPrivateOSX *controller, CB
 
     // TODO: isPrimary is ... always 'NO' - to be investigated.
     /*
-    using OSXBluetooth::qt_OS_limit;
     if (!cbService.isPrimary) {
         // Our guess included/not was probably wrong.
         newService->type &= ~QLowEnergyService::PrimaryService;
@@ -147,12 +146,9 @@ QLowEnergyControllerPrivateOSX::QLowEnergyControllerPrivateOSX(QLowEnergyControl
     Q_ASSERT_X(q, Q_FUNC_INFO, "invalid q_ptr (null)");
 
     using OSXBluetooth::LECBManagerNotifier;
-    using OSXBluetooth::qt_OS_limit;
 
     role = r;
 
-
-
     QScopedPointer<LECBManagerNotifier> notifier(new LECBManagerNotifier);
     if (role == QLowEnergyController::PeripheralRole) {
 #ifndef Q_OS_TVOS