handle.hpp

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#pragma once


#include <utility>


namespace planet::sdl {

An SDL handle

Stores a pointer to the resource T and frees it using the freeing function F.

In practice many of the freeing functions will behave properly when passed a nullptr, but for the sake of not having to look them all up, we perform a check in the destructor anyway.

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    template<typename T, void (*F)(T *)>
    class handle final {
        T *object = nullptr;

      public:
        handle() {}
        handle(T *t) : object{t} {}
        ~handle() { reset(); }

A handle is movable, but not copyable

 
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        handle(handle &&h) : object{std::exchange(h.object, nullptr)} {}
        handle(handle const &) = delete;
        handle &operator=(handle &&h) {
            std::swap(object, h.object);
            return *this;
        }
        handle &operator=(handle const &) = delete;

Access to the underlying pointer

 
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        T *get() const noexcept { return object; }
        T *operator->() const { return object; }

Force reset of the handle

 
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        void reset() {
            if (object) { F(std::exchange(object, nullptr)); }
        }
    };


}