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#pragma once
/*
* public 'deep' API to be used by external modules if they want to implement Lanes-aware userdata
* said modules can either link against lanes, or embed compat.cpp/h deep.cpp/h tools.cpp/h universe.cpp/h
*/
#include "lanesconf.h"
#include "uniquekey.hpp"
// forwards
enum class LookupMode;
class DeepFactory;
class Universe;
// #################################################################################################
// xxh64 of string "kDeepVersion_1" generated at https://www.pelock.com/products/hash-calculator
static constexpr UniqueKey kDeepVersion{ 0x91171AEC6641E9DBull, "kDeepVersion" };
// should be used as header for deep userdata
// a deep userdata is a full userdata that stores a single pointer to the actual DeepPrelude-derived object
struct DeepPrelude
{
UniqueKey const magic{ kDeepVersion };
// when stored in a keeper state, the full userdata doesn't have a metatable, so we need direct access to the factory
DeepFactory& factory;
// data is destroyed when refcount is 0
std::atomic<int> refcount{ 0 };
DeepPrelude(DeepFactory& factory_)
: factory{ factory_ }
{
}
void push(lua_State* L_) const;
};
// #################################################################################################
// external C modules should create a single object implementing that interface for each Deep userdata class they want to expose
class DeepFactory
{
protected:
// protected non-virtual destructor: Lanes won't manage the Factory's lifetime
DeepFactory() = default;
virtual ~DeepFactory() = default;
public:
// non-copyable, non-movable
DeepFactory(DeepFactory const&) = delete;
DeepFactory(DeepFactory const&&) = delete;
DeepFactory& operator=(DeepFactory const&) = delete;
DeepFactory& operator=(DeepFactory const&&) = delete;
private:
// NVI: private overrides
virtual void createMetatable(lua_State* L_) const = 0;
virtual void deleteDeepObjectInternal(lua_State* L_, DeepPrelude* o_) const = 0;
[[nodiscard]] virtual DeepPrelude* newDeepObjectInternal(lua_State* L_) const = 0;
[[nodiscard]] virtual std::string_view moduleName() const = 0;
private:
void storeDeepLookup(lua_State* L_) const;
public:
// NVI: public interface
static void DeleteDeepObject(lua_State* L_, DeepPrelude* o_);
[[nodiscard]] static bool IsDeepUserdata(lua_State* const L_, StackIndex const idx_);
[[nodiscard]] static DeepFactory* LookupFactory(lua_State* L_, StackIndex index_, LookupMode mode_);
static void PushDeepProxy(DestState L_, DeepPrelude* o_, UserValueCount nuv_, LookupMode mode_, lua_State* errL_);
void pushDeepUserdata(DestState L_, UserValueCount nuv_) const;
[[nodiscard]] DeepPrelude* toDeep(lua_State* L_, StackIndex index_) const;
};
// #################################################################################################
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