Add a wrapper for COM initialization

This helps ensure COM is initialized and deinitialized in order relative to
other objects (e.g. ComPtr).

1 files changed, 38 insertions, 0 deletions

diff --git a/common/comptr.h b/common/comptr.h
index 5a733ea2..9f8fd294 100644
--- a/common/comptr.h
+++ b/common/comptr.h
@@ -7,6 +7,44 @@
 #include <utility>
 #include <variant>
 
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+#include <objbase.h>
+
+struct ComWrapper {
+    HRESULT mStatus{};
+
+    ComWrapper(void *reserved, DWORD coinit)
+        : mStatus{CoInitializeEx(reserved, coinit)}
+    { }
+    ComWrapper(DWORD coinit=COINIT_APARTMENTTHREADED)
+        : mStatus{CoInitializeEx(nullptr, coinit)}
+    { }
+    ComWrapper(ComWrapper&& rhs) { mStatus = std::exchange(rhs.mStatus, E_FAIL); }
+    ComWrapper(const ComWrapper&) = delete;
+    ~ComWrapper() { if(SUCCEEDED(mStatus)) CoUninitialize(); }
+
+    ComWrapper& operator=(ComWrapper&& rhs)
+    {
+        if(SUCCEEDED(mStatus))
+            CoUninitialize();
+        mStatus = std::exchange(rhs.mStatus, E_FAIL);
+        return *this;
+    }
+    ComWrapper& operator=(const ComWrapper&) = delete;
+
+    HRESULT status() const noexcept { return mStatus; }
+    explicit operator bool() const noexcept { return SUCCEEDED(status()); }
+
+    void uninit()
+    {
+        if(SUCCEEDED(mStatus))
+            CoUninitialize();
+        mStatus = E_FAIL;
+    }
+};
+
+
 template<typename T>
 struct ComPtr {
     using element_type = T;