BlueZ: Fix crash when discovering GATT service without readable items

The jobs list might be empty and calling last() causes an assert in QVector.
This implies the current process under discovery does not have any
descriptors or characteristics which are readable. In such cases no
async read requests have to be put forward and the discovery is already done.

Change-Id: I8417bfcd146866cb16c295c9e9d4890270574a56
Reviewed-by: Oliver Wolff <oliver.wolff@qt.io>

1 files changed, 6 insertions, 2 deletions

diff --git a/src/bluetooth/qlowenergycontroller_bluezdbus.cpp b/src/bluetooth/qlowenergycontroller_bluezdbus.cpp
index e9087642..afc4b8c1 100644
--- a/src/bluetooth/qlowenergycontroller_bluezdbus.cpp
+++ b/src/bluetooth/qlowenergycontroller_bluezdbus.cpp
@@ -537,8 +537,12 @@ void QLowEnergyControllerPrivateBluezDBus::discoverServiceDetails(const QBluetoo
     serviceData->endHandle = runningHandle++;
 
     // last job is last step of service discovery
-    GattJob &lastJob = jobs.last();
-    lastJob.flags.setFlag(GattJob::LastServiceDiscovery, true);
+    if (!jobs.isEmpty()) {
+        GattJob &lastJob = jobs.last();
+        lastJob.flags.setFlag(GattJob::LastServiceDiscovery, true);
+    } else {
+        serviceData->setState(QLowEnergyService::ServiceDiscovered);
+    }
 
     scheduleNextJob();
 }