Windows::Devices::Enumeration::DeviceWatcher->Stop() 在扫描时崩溃

Question

我正在使用 C++ 编写 JNI DLL，为我们的 Java 应用程序提供一种访问 Windows 10 和 macOS 上的蓝牙 LE 设备的方法。它使用 C++/CX 访问 Windows 10 上的蓝牙 LE 对象，并使用 Objective-C++ 访问 macOS 上的等效项。但是，这个问题集中在我在 Windows 10 上遇到的崩溃，因此不会考虑特定于 macOS 的代码。当通过 JNI 或通过单独的 C 导出（使用命令）使用我的 DLL 时，会发生此崩溃我为简化调试而编写的线路测试应用程序）。

注意：CentralManagerCppCxShim 是一个 ref class，它只是在触发事件时回调到 CentralManagerImpl。

崩溃发生在 CentralManagerImpl 对象在扫描运行时被销毁（即 StartScan() 被调用）：当 _deviceWatcher 被销毁时它崩溃（无论我将其设置为 nullptr 或不设置都没有区别）。我对 BluetoothLEAdvertisementWatcher 有类似的问题，但正确删除析构函数中的事件处理程序使崩溃消失了。

代码摘录：

CentralManagerImpl.h:

class CentralManagerImpl: public CentralManager
{
private:
    CentralManagerCppCxShim ^_shim;
    DeviceWatcher ^_deviceWatcher;
    BluetoothLEAdvertisementWatcher ^_watcher;
    EventRegistrationToken _deviceWatcherAdded;
    EventRegistrationToken _deviceWatcherRemoved;
    EventRegistrationToken _deviceWatcherUpdated;
    EventRegistrationToken _watcherReceived;
public:
    CentralManagerImpl();
    ~CentralManagerImpl();
    void StartScan();
    void StopScan();
}

CentralManagerImpl.cpp:

CentralManagerImpl::CentralManagerImpl()
{
    _shim = ref new CentralManagerCppCxShim(this);
    _deviceWatcher = DeviceInformation::CreateWatcher(BluetoothLEDevice::GetDeviceSelectorFromPairingState(true));
    _deviceWatcherAdded = _deviceWatcher->Added += ref new TypedEventHandler<DeviceWatcher ^, DeviceInformation ^>(_shim, &CentralManagerCppCxShim::OnDeviceAdded);
    _deviceWatcherRemoved = _deviceWatcher->Removed += ref new TypedEventHandler<DeviceWatcher ^, DeviceInformationUpdate ^>(_shim, &CentralManagerCppCxShim::OnDeviceRemoved);
    _deviceWatcherUpdated = _deviceWatcher->Updated += ref new TypedEventHandler<DeviceWatcher ^, DeviceInformationUpdate ^>(_shim, &CentralManagerCppCxShim::OnDeviceUpdated);
    _deviceWatcher->Stopped += ref new TypedEventHandler<DeviceWatcher ^, Object ^>(_shim, &CentralManagerCppCxShim::OnDeviceWatcherStopped);
    _watcher = ref new BluetoothLEAdvertisementWatcher();
    BluetoothLEManufacturerData ^manufacturerData = ref new BluetoothLEManufacturerData();
    manufacturerData->CompanyId = MAKEWORD(HIBYTE(OUR_COMPANY_IDENTIFIER), LOBYTE(OUR_COMPANY_IDENTIFIER));
    _watcher->AdvertisementFilter->Advertisement->ManufacturerData->Append(manufacturerData);
    _watcher->Stopped += ref new TypedEventHandler<BluetoothLEAdvertisementWatcher ^, BluetoothLEAdvertisementWatcherStoppedEventArgs ^>(_shim, &CentralManagerCppCxShim::OnAdvertisementWatcherStopped);
    _watcherReceived = _watcher->Received += ref new TypedEventHandler<BluetoothLEAdvertisementWatcher ^, BluetoothLEAdvertisementReceivedEventArgs ^>(_shim, &CentralManagerCppCxShim::OnAdvertisementReceived);
}

CentralManagerImpl::~CentralManagerImpl()
{
    _watcher->Received -= _watcherReceived;
    _watcher = nullptr;
    _deviceWatcher->Updated -= _deviceWatcherUpdated;
    _deviceWatcher->Removed -= _deviceWatcherRemoved;
    _deviceWatcher->Added -= _deviceWatcherAdded;
    _deviceWatcher = nullptr; // this crashes :(
}

void CentralManagerImpl::StartScan()
{
    _deviceWatcher->Start();
    _watcher->Start();
}

void CentralManagerImpl::StopScan()
{
    _watcher->Stop();
    _deviceWatcher->Stop();
}

这是我得到的调用堆栈（是的，它很讨厌）：

ntdll.dll!_TppRaiseInvalidParameter@0()
ntdll.dll!_TpPostWork@4()
cfgmgr32.dll!TQuery::CloseQuery()
cfgmgr32.dll!_DevCloseObjectQuery@4()
Windows.Devices.Enumeration.dll!Watcher<class Windows::Devices::Enumeration::DeviceWatcher,struct Windows::Devices::Enumeration::IDeviceWatcher,struct Windows::Devices::Enumeration::IDeviceWatcher2,class Windows::Devices::Enumeration::DeviceInformation,struct Windows::Devices::Enumeration::IDeviceInformation,struct Windows::Devices::Enumeration::IDeviceInformation2,class DeviceInformationServer,class Windows::Devices::Enumeration::DeviceInformationUpdate,struct Windows::Devices::Enumeration::IDeviceInformationUpdate,class DeviceInformationUpdateServer,&unsigned short const * const RuntimeClass_Windows_Devices_Enumeration_DeviceWatcher>::Impl::EndQuery(void)
Windows.Devices.Enumeration.dll!Watcher<class Windows::Devices::Enumeration::DeviceWatcher,struct Windows::Devices::Enumeration::IDeviceWatcher,struct Windows::Devices::Enumeration::IDeviceWatcher2,class Windows::Devices::Enumeration::DeviceInformation,struct Windows::Devices::Enumeration::IDeviceInformation,struct Windows::Devices::Enumeration::IDeviceInformation2,class DeviceInformationServer,class Windows::Devices::Enumeration::DeviceInformationUpdate,struct Windows::Devices::Enumeration::IDeviceInformationUpdate,class DeviceInformationUpdateServer,&unsigned short const * const RuntimeClass_Windows_Devices_Enumeration_DeviceWatcher>::Impl::Stop(bool)
Windows.Devices.Enumeration.dll!Watcher<class Windows::Devices::Enumeration::DeviceWatcher,struct Windows::Devices::Enumeration::IDeviceWatcher,struct Windows::Devices::Enumeration::IDeviceWatcher2,class Windows::Devices::Enumeration::DeviceInformation,struct Windows::Devices::Enumeration::IDeviceInformation,struct Windows::Devices::Enumeration::IDeviceInformation2,class DeviceInformationServer,class Windows::Devices::Enumeration::DeviceInformationUpdate,struct Windows::Devices::Enumeration::IDeviceInformationUpdate,class DeviceInformationUpdateServer,&unsigned short const * const RuntimeClass_Windows_Devices_Enumeration_DeviceWatcher>::~Watcher<class Windows::Devices::Enumeration::DeviceWatcher,struct Windows::Devices::Enumeration::IDeviceWatcher,struct Windows::Devices::Enumeration::IDeviceWatcher2,class Windows::Devices::Enumeration::DeviceInformation,struct Windows::Devices::Enumeration::IDeviceInformation,struct Windows::Devices::Enumeration::IDeviceInformation2,class DeviceInformationServer,class Windows::Devices::Enumeration::Devic()
Windows.Devices.Enumeration.dll!Watcher<class Windows::Devices::Enumeration::DeviceWatcher,struct Windows::Devices::Enumeration::IDeviceWatcher,struct Windows::Devices::Enumeration::IDeviceWatcher2,class Windows::Devices::Enumeration::DeviceInformation,struct Windows::Devices::Enumeration::IDeviceInformation,struct Windows::Devices::Enumeration::IDeviceInformation2,class DeviceInformationServer,class Windows::Devices::Enumeration::DeviceInformationUpdate,struct Windows::Devices::Enumeration::IDeviceInformationUpdate,class DeviceInformationUpdateServer,&unsigned short const * const RuntimeClass_Windows_Devices_Enumeration_DeviceWatcher>::`vector deleting destructor'(unsigned int)
Windows.Devices.Enumeration.dll!Microsoft::WRL::Details::RuntimeClass<struct Microsoft::WRL::Details::InterfaceList<struct Windows::Devices::Enumeration::IDeviceWatcher,struct Microsoft::WRL::Details::InterfaceList<struct Windows::Devices::Enumeration::IDeviceWatcher2,struct Microsoft::WRL::Details::InterfaceList<struct Windows::Foundation::IClosable,struct Microsoft::WRL::Details::InterfaceList<class Microsoft::WRL::FtmBase,class Microsoft::WRL::Details::Nil> > > >,struct Microsoft::WRL::RuntimeClassFlags<3>,1,1,0>::Release(void)
mydll.dll!__abi_winrt_ptr_assign(void * * __ppTargetArg, const volatile Platform::Object ^ __objArg) Line 405
mydll.dll!CentralManagerImpl::~CentralManagerImpl() Line 64
[External Code] 
//…

Answer 1

经过深入调查，我得出以下结论：

当 DLL 作为 UWP 工作线程被卸载（DLL_PROCESS_DETACH）时，系统无法在 CentralManagerImpl C++ class 的默认析构函数中销毁 DeviceWatcher已经被系统终止了。我找到的唯一可行的解决方案是向我的 DLL 添加一个新的导出，以明确拆除我的 C++ class.

我会将此标记为已回答，因为我认为没有其他解决方法。

Windows::Devices::Enumeration::DeviceWatcher->Stop() 在扫描时崩溃

Windows::Devices::Enumeration::DeviceWatcher->Stop() crashes when scanning

c++-cx

bluetooth-lowenergy

uwp