Move the ComPtr wrapper to a common header

1 files changed, 70 insertions, 0 deletions

diff --git a/common/comptr.h b/common/comptr.h
new file mode 100644
index 00000000..c238991a
--- /dev/null
+++ b/common/comptr.h
@@ -0,0 +1,70 @@
+#ifndef COMMON_COMPTR_H
+#define COMMON_COMPTR_H
+
+#include <cstddef>
+#include <utility>
+
+
+template<typename T>
+class ComPtr {
+    T *mPtr{nullptr};
+
+public:
+    ComPtr() noexcept = default;
+    ComPtr(const ComPtr &rhs) : mPtr{rhs.mPtr} { if(mPtr) mPtr->AddRef(); }
+    ComPtr(ComPtr&& rhs) noexcept : mPtr{rhs.mPtr} { rhs.mPtr = nullptr; }
+    ComPtr(std::nullptr_t) noexcept { }
+    explicit ComPtr(T *ptr) noexcept : mPtr{ptr} { }
+    ~ComPtr() { if(mPtr) mPtr->Release(); }
+
+    ComPtr& operator=(const ComPtr &rhs)
+    {
+        if(!rhs.mPtr)
+        {
+            if(mPtr)
+                mPtr->Release();
+            mPtr = nullptr;
+        }
+        else
+        {
+            rhs.mPtr->AddRef();
+            try {
+                if(mPtr)
+                    mPtr->Release();
+                mPtr = rhs.mPtr;
+            }
+            catch(...) {
+                rhs.mPtr->Release();
+                throw;
+            }
+        }
+        return *this;
+    }
+    ComPtr& operator=(ComPtr&& rhs)
+    {
+        if(mPtr)
+            mPtr->Release();
+        mPtr = rhs.mPtr;
+        rhs.mPtr = nullptr;
+        return *this;
+    }
+
+    operator bool() const noexcept { return mPtr != nullptr; }
+
+    T& operator*() const noexcept { return *mPtr; }
+    T* operator->() const noexcept { return mPtr; }
+    T* get() const noexcept { return mPtr; }
+    T** getPtr() noexcept { return &mPtr; }
+
+    T* release() noexcept
+    {
+        T *ret{mPtr};
+        mPtr = nullptr;
+        return ret;
+    }
+
+    void swap(ComPtr &rhs) noexcept { std::swap(mPtr, rhs.mPtr); }
+    void swap(ComPtr&& rhs) noexcept { std::swap(mPtr, rhs.mPtr); }
+};
+
+#endif