Implement reduced service discovery on Linux-BlueZ

This patch implements reduced service discovery on Linux in the
BlueZ backend (without DBUS). Reading of characteristics and
descriptors is skipped in service discovery.

Task-number: QTBUG-75349
Fixes: QTBUG-91960
Change-Id: Ie15462d79d76d5d2c49daf223b33f03b2a9b2672
Reviewed-by: Timur Pocheptsov <timur.pocheptsov@qt.io>

3 files changed, 18 insertions, 15 deletions

diff --git a/src/bluetooth/qlowenergycontroller_bluez.cpp b/src/bluetooth/qlowenergycontroller_bluez.cpp
index fe9605d2..52c13304 100644
--- a/src/bluetooth/qlowenergycontroller_bluez.cpp
+++ b/src/bluetooth/qlowenergycontroller_bluez.cpp
@@ -1566,7 +1566,6 @@ void QLowEnergyControllerPrivateBluez::sendReadByGroupRequest(
 void QLowEnergyControllerPrivateBluez::discoverServiceDetails(const QBluetoothUuid &service,
                                                               QLowEnergyService::DiscoveryMode mode)
 {
-    Q_UNUSED(mode);
     if (!serviceList.contains(service)) {
         qCWarning(QT_BT_BLUEZ) << "Discovery of unknown service" << service.toString()
                                << "not possible";
@@ -1574,6 +1573,7 @@ void QLowEnergyControllerPrivateBluez::discoverServiceDetails(const QBluetoothUu
     }
 
     QSharedPointer<QLowEnergyServicePrivate> serviceData = serviceList.value(service);
+    serviceData->mode = mode;
     serviceData->characteristicList.clear();
     sendReadByTypeRequest(serviceData, serviceData->startHandle, GATT_INCLUDED_SERVICE);
 }
@@ -1629,6 +1629,16 @@ void QLowEnergyControllerPrivateBluez::readServiceValues(
 
     QSharedPointer<QLowEnergyServicePrivate> service = serviceList.value(serviceUuid);
 
+    if (service->mode == QLowEnergyService::SkipValueDiscovery) {
+        if (readCharacteristics) {
+            // -> continue with descriptor discovery
+            discoverServiceDescriptors(service->uuid);
+        } else {
+            service->setState(QLowEnergyService::RemoteServiceDiscovered);
+        }
+        return;
+    }
+
     // pair.first -> target attribute
     // pair.second -> context information for read request
     QPair<QLowEnergyHandle, quint32> pair;
diff --git a/src/bluetooth/qlowenergyserviceprivate.cpp b/src/bluetooth/qlowenergyserviceprivate.cpp
index 91364155..0a401d8d 100644
--- a/src/bluetooth/qlowenergyserviceprivate.cpp
+++ b/src/bluetooth/qlowenergyserviceprivate.cpp
@@ -43,15 +43,7 @@
 
 QT_BEGIN_NAMESPACE
 
-QLowEnergyServicePrivate::QLowEnergyServicePrivate(QObject *parent) :
-    QObject(parent),
-    startHandle(0),
-    endHandle(0),
-    type(QLowEnergyService::PrimaryService),
-    state(QLowEnergyService::InvalidService),
-    lastError(QLowEnergyService::NoError)
-{
-}
+QLowEnergyServicePrivate::QLowEnergyServicePrivate(QObject *parent) : QObject(parent) { }
 
 QLowEnergyServicePrivate::~QLowEnergyServicePrivate()
 {
diff --git a/src/bluetooth/qlowenergyserviceprivate_p.h b/src/bluetooth/qlowenergyserviceprivate_p.h
index a74743d1..cf53b2e9 100644
--- a/src/bluetooth/qlowenergyserviceprivate_p.h
+++ b/src/bluetooth/qlowenergyserviceprivate_p.h
@@ -111,14 +111,15 @@ signals:
                            const QByteArray &newValue);
 
 public:
-    QLowEnergyHandle startHandle;
-    QLowEnergyHandle endHandle;
+    QLowEnergyHandle startHandle = 0;
+    QLowEnergyHandle endHandle = 0;
 
     QBluetoothUuid uuid;
     QList<QBluetoothUuid> includedServices;
-    QLowEnergyService::ServiceTypes type;
-    QLowEnergyService::ServiceState state;
-    QLowEnergyService::ServiceError lastError;
+    QLowEnergyService::ServiceTypes type = QLowEnergyService::PrimaryService;
+    QLowEnergyService::ServiceState state = QLowEnergyService::InvalidService;
+    QLowEnergyService::ServiceError lastError = QLowEnergyService::NoError;
+    QLowEnergyService::DiscoveryMode mode = QLowEnergyService::FullDiscovery;
 
     QHash<QLowEnergyHandle, CharData> characteristicList;