1 files changed, 18 insertions, 0 deletions
diff --git a/win32/WinTypes.h b/win32/WinTypes.h
index 9badd70a8..9c930bb7c 100644
--- a/win32/WinTypes.h
+++ b/win32/WinTypes.h
@@ -38,6 +38,24 @@ struct UnknownReleaser {
 	}
 };
 
+// Wrap COM IUnknown::QueryInterface to produce std::unique_ptr objects to help
+// ensure safe reference counting.
+template<typename T>
+inline HRESULT UniquePtrFromQI(IUnknown *source, REFIID riid, std::unique_ptr<T, UnknownReleaser> &destination) noexcept {
+	T *ptr{};
+	HRESULT hr = E_FAIL;
+	try {
+		hr = source->QueryInterface(riid, reinterpret_cast<void **>(&ptr));
+	} catch (...) {
+		// Shouldn't have exceptions from QueryInterface but not marked noexcept
+	}
+	if (SUCCEEDED(hr)) {
+		destination.reset(ptr);
+	} else {
+		destination.reset();
+	}
+	return hr;
+}
 
 /// Find a function in a DLL and convert to a function pointer.
 /// This avoids undefined and conditionally defined behaviour.