winrt: Do not crash when trying to an unreachable paired LE device

As device discovery returns every paired device on winrt, it is possible
that we try to connect to a device, that is paired but not available.
When doing so the application should not crash but state that there
was an error connecting to the device.

Task-number: QTBUG-64480
Change-Id: I8d79f6da1de2b0bda7a51a7cfd068bb4a6057257
Reviewed-by: Alex Blasche <alexander.blasche@qt.io>
Reviewed-by: Miguel Costa <miguel.costa@qt.io>
Reviewed-by: Maurice Kalinowski <maurice.kalinowski@qt.io>

1 files changed, 11 insertions, 1 deletions

diff --git a/src/bluetooth/qlowenergycontroller_winrt.cpp b/src/bluetooth/qlowenergycontroller_winrt.cpp
index ed36790b..1e06dedb 100644
--- a/src/bluetooth/qlowenergycontroller_winrt.cpp
+++ b/src/bluetooth/qlowenergycontroller_winrt.cpp
@@ -400,7 +400,17 @@ void QLowEnergyControllerPrivate::connectToDevice()
             Q_ASSERT_SUCCEEDED(hr);
             ComPtr<IGattReadResult> result;
             hr = QWinRTFunctions::await(op, result.GetAddressOf());
-            Q_ASSERT_SUCCEEDED(hr);
+            if (hr == E_INVALIDARG) {
+                // E_INVALIDARG happens when user tries to connect to a device that was paired
+                // before but is not available.
+                qCDebug(QT_BT_WINRT) << "Could not obtain characteristic read result that triggers"
+                                        "device connection. Is the device reachable?";
+                setError(QLowEnergyController::ConnectionError);
+                setState(QLowEnergyController::UnconnectedState);
+                return;
+            } else {
+                Q_ASSERT_SUCCEEDED(hr);
+            }
             ComPtr<ABI::Windows::Storage::Streams::IBuffer> buffer;
             hr = result->get_Value(&buffer);
             Q_ASSERT_SUCCEEDED(hr);