gui_region_tpl.hpp

#ifndef LXGUI_GUI_REGION_TPL_HPP
#define LXGUI_GUI_REGION_TPL_HPP
 
#include "lxgui/gui_frame.hpp"
#include "lxgui/gui_manager.hpp"
#include "lxgui/gui_region.hpp"
#include "lxgui/gui_registry.hpp"
#include "lxgui/gui_root.hpp"
#include "lxgui/lxgui.hpp"
#include "lxgui/utils_observer.hpp"
#include "lxgui/utils_string.hpp"
 
#include <lxgui/extern_sol2_state.hpp>
 
namespace sol {
 
template<typename T>
struct unique_usertype_traits<lxgui::utils::observer_ptr<T>> {
    static T* get(lua_State*, const lxgui::utils::observer_ptr<T>& pointer) noexcept {
        return pointer.get();
    }
 
    static bool is_null(lua_State*, const lxgui::utils::observer_ptr<T>& pointer) noexcept {
        return pointer.expired();
    }
};
 
} // namespace sol
namespace lxgui::gui {
 
template<typename T>
void sol_lua_check_access(
    sol::types<T>, lua_State* lua, int index, sol::stack::record& /*tracking*/) {
    // NB: not sure why, but using tracking here leads to issues later on, so
    // ignore it for now.
 
    using RegionType = std::remove_pointer_t<T>;
 
    sol::optional<lxgui::utils::observer_ptr<RegionType>&> optional =
        sol::stack::check_get<lxgui::utils::observer_ptr<RegionType>&>(
            lua, index, sol::no_panic /*, tracking*/);
 
    if (!optional.has_value())
        return;
 
    if (optional->expired())
        throw sol::error("object has been deleted");
}
 
inline utils::observer_ptr<region>
get_object(manager& mgr, const std::variant<std::string, region*>& parent) {
    return std::visit(
        [&](const auto& value) -> utils::observer_ptr<region> {
            using data_type = std::decay_t<decltype(value)>;
            if constexpr (std::is_same_v<data_type, std::string>) {
                if (utils::has_no_content(value))
                    return nullptr;
 
                auto parent_obj = mgr.get_root().get_registry().get_region_by_name(value);
                if (!parent_obj)
                    throw sol::error("no region with name \"" + value + "\"");
 
                return parent_obj;
            } else {
                return observer_from(value);
            }
        },
        parent);
}
 
template<typename T>
utils::observer_ptr<T> get_object(manager& mgr, const std::variant<std::string, T*>& parent) {
    return std::visit(
        [&](const auto& value) -> utils::observer_ptr<T> {
            using data_type = std::decay_t<decltype(value)>;
            if constexpr (std::is_same_v<data_type, std::string>) {
                if (utils::has_no_content(value))
                    return nullptr;
 
                auto parent_object = mgr.get_root().get_registry().get_region_by_name(value);
                if (!parent_object)
                    throw sol::error("no region with name \"" + value + "\"");
 
                auto parent_obj = down_cast<T>(parent_object);
                if (!parent_obj)
                    throw sol::error(
                        "region \"" + value + "\" is not a " + std::string(T::class_name));
 
                return parent_obj;
            } else {
                return observer_from(value);
            }
        },
        parent);
}
 
#if defined(LXGUI_COMPILER_EMSCRIPTEN)
// Workaround for compiler crash in Emscripten; explicitly convert member
// function pointers to free functions. sol2 is able to do this automatically,
// but Emscripten/clang is not happy about it.
template<typename T, T F>
struct member_function_holder;
 
template<typename R, typename T, typename... Args, R (T::*Function)(Args...)>
struct member_function_holder<R (T::*)(Args...), Function> {
    static constexpr auto make_free_function() {
        return [](T& self, Args... args) { return (self.*Function)(std::move(args)...); };
    }
};
 
template<typename R, typename T, typename... Args, R (T::*Function)(Args...) const>
struct member_function_holder<R (T::*)(Args...) const, Function> {
    static constexpr auto make_free_function() {
        return [](const T& self, Args... args) { return (self.*Function)(std::move(args)...); };
    }
};
 
template<auto T>
constexpr auto member_function() {
    return member_function_holder<decltype(T), T>::make_free_function();
}
#else
// Simply use the member function pointer directly for all other compilers.
template<auto T>
constexpr auto member_function() {
    return T;
}
#endif
 
template<typename T>
void region::create_glue_(T& self) {
    get_lua_().globals()[get_name()] = observer_from(&self);
}
 
template<typename T>
void region::initialize_(T& self, const region_core_attributes& /*attr*/) {
    if (!is_virtual())
        create_glue_(self);
}
 
template<typename T>
const std::vector<std::string>& region::get_type_list_impl_() {
    if constexpr (std::is_same_v<T, region>) {
        static const std::vector<std::string> type = {region::class_name};
 
        return type;
    } else {
        static const std::vector<std::string> type = []() {
            using base = typename T::base;
            auto list  = get_type_list_impl_<base>();
            list.push_back(T::class_name);
            return list;
        }();
 
        return type;
    }
}
 
} // namespace lxgui::gui
 
#endif