Fix crash when unpairing device while scanning

[fotiDim]

No description provided.

[gemini-code-assist]

Summary of Changes

Hello @fotiDim, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request addresses a critical stability issue by preventing application crashes that could occur when a Bluetooth device is unpaired while a scan is actively in progress. The changes focus on adding defensive programming measures, specifically exception handling and null checks, to ensure the application gracefully handles unexpected states of device and advertisement data.

Highlights

• Crash Prevention: Implemented robust error handling in the OnDeviceInfoReceived method by wrapping property access in a try-catch block. This prevents crashes that could occur if device information becomes invalid or stale, particularly during device unpairing while scanning.
• Null Pointer Safety: Introduced null checks for Advertisement data and DeviceInformation objects within the OnAdvertisementReceived method. This proactively prevents crashes caused by attempting to access members of invalid or stale data structures during Bluetooth scanning.

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[gemini-code-assist]

Code Review

This pull request addresses a crash that occurs when a device is unpaired during a scan by introducing try-catch blocks and nullptr checks to handle stale device information. The changes are effective in preventing the crash. My review provides suggestions to enhance the robustness and maintainability of this new error handling code, such as using more specific exception types instead of a general catch(...) and refactoring repeated checks for better readability.

[gemini-code-assist]

While adding a try-catch block is a good way to prevent the crash, catching all exceptions with ... can hide other potential issues. It would be better to catch the specific exception type you expect, which is likely winrt::hresult_error when dealing with stale WinRT objects. This makes the code safer and easier to debug. Also, the log message could be more descriptive.

    catch (const winrt::hresult_error& e)
    {
      std::cout << "Failed to process device info, likely due to unpairing: " << to_string(e.message()) << std::endl;
    }

[gemini-code-assist]

There are multiple if (args.Advertisement() != nullptr) checks in this function. To improve readability and avoid repeated calls to args.Advertisement(), you could cache the result in a local variable at the beginning of the function and use that variable for all subsequent checks and operations on the advertisement object. The ternary operator can also make this part more concise.

      auto advertisement = args.Advertisement();
      std::string name = advertisement ? to_string(advertisement.LocalName()) : "";
      // TODO: Use `advertisement` in subsequent null checks in this function.

[gemini-code-assist]

Using catch (...) is a bit broad and can hide unrelated errors. It's better to catch the specific exception you expect to ignore, which is likely winrt::hresult_error for stale WinRT objects. This makes the code more robust.

        catch (const winrt::hresult_error&)
        {
          // Ignore errors from accessing stale DeviceInformation
        }