src/brussel.common/ScopedResource.hpp


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#pragma once

#include <type_traits>

/// std::unique_ptr, but for non-pointer resources
template <typename T, typename TDeleter, T kNullValue = T()>
	requires std::is_trivial_v<T> && std::equality_comparable<T>
class ScopedResource {
private:
	T mValue;

public:
	ScopedResource()
		: mValue{ kNullValue } {}
	explicit ScopedResource(T t)
		: mValue{ std::move(t) } {}

	ScopedResource(const ScopedResource& that) = delete;
	ScopedResource& operator=(const ScopedResource& that) = delete;

	ScopedResource(ScopedResource&& that) noexcept
		: mValue(that.mValue) {}
	ScopedResource& operator=(ScopedResource&& that) noexcept {
		if (this == &that)
			return *this;
		TDeleter::DeleteObject(mValue);
		mValue = that.mValue;
		that.mValue = kNullValue;
		return *this;
	}

	ScopedResource& operator=(T newValue) {
		TDeleter::DeleteObject(mValue);
		mValue = newValue;
		return *this;
	}

	~ScopedResource() {
		TDeleter::DeleteObject(mValue);
	}

	explicit operator bool() const {
		return mValue != kNullValue;
	}

	const T& get() const { return mValue; }
	T& get() { return mValue; }

	T release() {
		T tmp = mValue;
		mValue = kNullValue;
		return tmp;
	}
};