core/util: move DropEmitter to utils and add generic accessor macros

src/core/types.hpp

@@ -69,28 +69,3 @@ bool isOpposing(Flags edges);
 }; // namespace Edges
 
 Q_DECLARE_OPERATORS_FOR_FLAGS(Edges::Flags);
-
-// NOLINTBEGIN
-#define DROP_EMIT(object, func)                                                                    \
-	DropEmitter(object, static_cast<void (*)(typeof(object))>([](typeof(object) o) { o->func(); }))
-// NOLINTEND
-
-class DropEmitter {
-public:
-	template <class O>
-	DropEmitter(O* object, void (*signal)(O*))
-	    : object(object)
-	    , signal(*reinterpret_cast<void (*)(void*)>(signal)) {} // NOLINT
-
-	DropEmitter() = default;
-	DropEmitter(DropEmitter&& other) noexcept;
-	DropEmitter& operator=(DropEmitter&& other) noexcept;
-	~DropEmitter();
-	Q_DISABLE_COPY(DropEmitter);
-
-	void call();
-
-private:
-	void* object = nullptr;
-	void (*signal)(void*) = nullptr;
-};