winrt: Fix reading of descriptor values

We have to access the service data instead of relying on passed
references as these references might have run out of scope and thus
might not be valid any more.

Fixes: QTBUG-75070
Change-Id: I02ad0fef2337488c926fb950ddf2da6eda56a396
Reviewed-by: Alex Blasche <alexander.blasche@qt.io>

1 files changed, 12 insertions, 8 deletions

diff --git a/src/bluetooth/qlowenergycontroller_winrt.cpp b/src/bluetooth/qlowenergycontroller_winrt.cpp
index 6efa2231..f946b541 100644
--- a/src/bluetooth/qlowenergycontroller_winrt.cpp
+++ b/src/bluetooth/qlowenergycontroller_winrt.cpp
@@ -779,7 +779,7 @@ void QLowEnergyControllerPrivateWinRT::readDescriptor(const QSharedPointer<QLowE
 
     HRESULT hr;
     hr = QEventDispatcherWinRT::runOnXamlThread([charHandle, descHandle, service, this]() {
-        QLowEnergyServicePrivate::CharData charData = service->characteristicList.value(charHandle);
+        const QLowEnergyServicePrivate::CharData charData = service->characteristicList.value(charHandle);
         ComPtr<IGattCharacteristic> characteristic = getNativeCharacteristic(service->uuid, charData.uuid);
         if (!characteristic) {
             qCDebug(QT_BT_WINRT) << "Could not obtain native characteristic" << charData.uuid
@@ -791,12 +791,13 @@ void QLowEnergyControllerPrivateWinRT::readDescriptor(const QSharedPointer<QLowE
         // Get native descriptor
         if (!charData.descriptorList.contains(descHandle))
             qCDebug(QT_BT_WINRT) << "Descriptor" << descHandle << "cannot be found in characteristic" << charHandle;
-        QLowEnergyServicePrivate::DescData descData = charData.descriptorList.value(descHandle);
-        if (descData.uuid == QBluetoothUuid(QBluetoothUuid::ClientCharacteristicConfiguration)) {
+        const QLowEnergyServicePrivate::DescData descData = charData.descriptorList.value(descHandle);
+        const QBluetoothUuid descUuid = descData.uuid;
+        if (descUuid == QBluetoothUuid(QBluetoothUuid::ClientCharacteristicConfiguration)) {
             ComPtr<IAsyncOperation<ClientCharConfigDescriptorResult *>> readOp;
             HRESULT hr = characteristic->ReadClientCharacteristicConfigurationDescriptorAsync(&readOp);
             Q_ASSERT_SUCCEEDED(hr);
-            auto readCompletedLambda = [&charData, charHandle, &descData, descHandle, service]
+            auto readCompletedLambda = [charHandle, descHandle, service]
                     (IAsyncOperation<ClientCharConfigDescriptorResult *> *op, AsyncStatus status)
             {
                 if (status == AsyncStatus::Canceled || status == AsyncStatus::Error) {
@@ -837,9 +838,11 @@ void QLowEnergyControllerPrivateWinRT::readDescriptor(const QSharedPointer<QLowE
                     service->setError(QLowEnergyService::DescriptorReadError);
                     return S_OK;
                 }
+                QLowEnergyServicePrivate::DescData descData;
+                descData.uuid = QBluetoothUuid::ClientCharacteristicConfiguration;
                 descData.value = QByteArray(2, Qt::Uninitialized);
                 qToLittleEndian(result, descData.value.data());
-                charData.descriptorList.insert(descHandle, descData);
+                service->characteristicList[charHandle].descriptorList[descHandle] = descData;
                 emit service->descriptorRead(QLowEnergyDescriptor(service, charHandle, descHandle),
                     descData.value);
                 return S_OK;
@@ -857,7 +860,7 @@ void QLowEnergyControllerPrivateWinRT::readDescriptor(const QSharedPointer<QLowE
             ComPtr<IAsyncOperation<GattReadResult*>> readOp;
             hr = descriptor->ReadValueWithCacheModeAsync(BluetoothCacheMode_Uncached, &readOp);
             Q_ASSERT_SUCCEEDED(hr);
-            auto readCompletedLambda = [&charData, charHandle, &descData, descHandle, service]
+            auto readCompletedLambda = [charHandle, descHandle, descUuid, service]
                     (IAsyncOperation<GattReadResult*> *op, AsyncStatus status)
             {
                 if (status == AsyncStatus::Canceled || status == AsyncStatus::Error) {
@@ -873,11 +876,12 @@ void QLowEnergyControllerPrivateWinRT::readDescriptor(const QSharedPointer<QLowE
                     service->setError(QLowEnergyService::DescriptorReadError);
                     return S_OK;
                 }
-                if (descData.uuid == QBluetoothUuid::CharacteristicUserDescription)
+                QLowEnergyServicePrivate::DescData descData;
+                if (descUuid == QBluetoothUuid::CharacteristicUserDescription)
                     descData.value = byteArrayFromGattResult(descriptorValue, true);
                 else
                     descData.value = byteArrayFromGattResult(descriptorValue);
-                charData.descriptorList.insert(descHandle, descData);
+                service->characteristicList[charHandle].descriptorList[descHandle] = descData;
                 emit service->descriptorRead(QLowEnergyDescriptor(service, charHandle, descHandle),
                     descData.value);
                 return S_OK;