Don't expose LuaUtil::Callback to lua

apps/openmw/mwlua/nearbybindings.cpp

@@ -115,9 +115,9 @@ namespace MWLua
             MWBase::Environment::get().getWorld()->castRenderingRay(res, from, to, false, false);
             return res;
         };
-        api["asyncCastRenderingRay"] = [context](const LuaUtil::Callback& callback, const osg::Vec3f& from,
-                                           const osg::Vec3f& to) {
-            context.mLuaManager->addAction([context, callback, from, to] {
+        api["asyncCastRenderingRay"] = [context](
+                                           const sol::table& callback, const osg::Vec3f& from, const osg::Vec3f& to) {
+            context.mLuaManager->addAction([context, callback = LuaUtil::Callback::fromLua(callback), from, to] {
                 MWPhysics::RayCastingResult res;
                 MWBase::Environment::get().getWorld()->castRenderingRay(res, from, to, false, false);
                 context.mLuaManager->queueCallback(callback, sol::main_object(context.mLua->sol(), sol::in_place, res));

apps/openmw_test_suite/lua/test_storage.cpp

@@ -2,7 +2,7 @@
 #include <gmock/gmock.h>
 #include <gtest/gtest.h>
 
-#include <components/lua/scriptscontainer.hpp>
+#include <components/lua/asyncpackage.hpp>
 #include <components/lua/storage.hpp>
 
 namespace
@@ -24,15 +24,16 @@ namespace
         LuaUtil::LuaStorage storage(mLua);
 
         std::vector<std::string> callbackCalls;
-        LuaUtil::Callback callback{ sol::make_object(mLua,
-                                        [&](const std::string& section, const sol::optional<std::string>& key) {
+        sol::table callbackHiddenData(mLua, sol::create);
+        callbackHiddenData[LuaUtil::ScriptsContainer::sScriptIdKey] = LuaUtil::ScriptId{};
+        sol::table callback(mLua, sol::create);
+        callback[1] = [&](const std::string& section, const sol::optional<std::string>& key) {
             if (key)
                 callbackCalls.push_back(section + "_" + *key);
             else
                 callbackCalls.push_back(section + "_*");
-                                        }),
-            sol::table(mLua, sol::create) };
-        callback.mHiddenData[LuaUtil::ScriptsContainer::sScriptIdKey] = LuaUtil::ScriptId{};
+        };
+        callback[2] = LuaUtil::AsyncPackageId{ nullptr, 0, callbackHiddenData };
 
         mLua["mutable"] = storage.getMutableSection("test");
         mLua["ro"] = storage.getReadOnlySection("test");

components/lua/asyncpackage.cpp

@@ -22,6 +22,21 @@ namespace LuaUtil
         std::string mName;
     };
 
+    Callback Callback::fromLua(const sol::table& t)
+    {
+        return Callback{ t.raw_get<sol::main_protected_function>(1), t.raw_get<AsyncPackageId>(2).mHiddenData };
+    }
+
+    bool Callback::isLuaCallback(const sol::object& t)
+    {
+        if (!t.is<sol::table>())
+            return false;
+        sol::object meta = sol::table(t)[sol::metatable_key];
+        if (!meta.is<sol::table>())
+            return false;
+        return sol::table(meta).raw_get_or<bool, std::string_view, bool>("isCallback", false);
+    }
+
     sol::function getAsyncPackageInitializer(
         lua_State* L, std::function<double()> simulationTimeFn, std::function<double()> gameTimeFn)
     {
@@ -53,13 +68,20 @@ namespace LuaUtil
                   asyncId.mContainer->setupUnsavableTimer(
                       TimerType::GAME_TIME, gameTimeFn() + delay, asyncId.mScriptId, std::move(callback));
               };
-        api["callback"] = [](const AsyncPackageId& asyncId, sol::main_protected_function fn) -> Callback {
-            return Callback{ std::move(fn), asyncId.mHiddenData };
-        };
 
-        sol::usertype<Callback> callbackType = lua.new_usertype<Callback>("Callback");
-        callbackType[sol::meta_function::call]
-            = [](const Callback& callback, sol::variadic_args va) { return callback.call(sol::as_args(va)); };
+        sol::table callbackMeta = sol::table::create(L);
+        callbackMeta[sol::meta_function::call] = [](const sol::table& callback, sol::variadic_args va) {
+            return Callback::fromLua(callback).call(sol::as_args(va));
+        };
+        callbackMeta[sol::meta_function::to_string] = [] { return "Callback"; };
+        callbackMeta[sol::meta_function::metatable] = false;
+        callbackMeta["isCallback"] = true;
+        api["callback"] = [callbackMeta](const AsyncPackageId& asyncId, sol::main_protected_function fn) -> sol::table {
+            sol::table c = sol::table::create(fn.lua_state(), 2);
+            c.raw_set(1, std::move(fn), 2, asyncId);
+            c[sol::metatable_key] = callbackMeta;
+            return c;
+        };
 
         auto initializer = [](sol::table hiddenData) {
             ScriptId id = hiddenData[ScriptsContainer::sScriptIdKey];

components/lua/asyncpackage.hpp

@@ -22,6 +22,9 @@ namespace LuaUtil
         sol::main_protected_function mFunc;
         sol::table mHiddenData; // same object as Script::mHiddenData in ScriptsContainer
 
+        static bool isLuaCallback(const sol::object&);
+        static Callback fromLua(const sol::table&);
+
         bool isValid() const { return mHiddenData[ScriptsContainer::sScriptIdKey] != sol::nil; }
 
         template <typename... Args>

components/lua/storage.cpp

@@ -111,7 +111,7 @@ namespace LuaUtil
             return section.mSection->get(key).getCopy(s);
         };
         sview["asTable"] = [](const SectionView& section) { return section.mSection->asTable(); };
-        sview["subscribe"] = [](const SectionView& section, const Callback& callback) {
+        sview["subscribe"] = [](const SectionView& section, const sol::table& callback) {
             std::vector<Callback>& callbacks = section.mSection->mCallbacks;
             if (!callbacks.empty() && callbacks.size() == callbacks.capacity())
             {
@@ -119,7 +119,7 @@ namespace LuaUtil
                     std::remove_if(callbacks.begin(), callbacks.end(), [&](const Callback& c) { return !c.isValid(); }),
                     callbacks.end());
             }
-            callbacks.push_back(callback);
+            callbacks.push_back(Callback::fromLua(callback));
         };
         sview["reset"] = [](const SectionView& section, const sol::optional<sol::table>& newValues) {
             if (section.mReadOnly)

components/lua_ui/element.cpp

@@ -106,11 +106,11 @@ namespace LuaUi
                 throw std::logic_error("The \"events\" layout field must be a table of callbacks");
             auto events = eventsObj.as<sol::table>();
             events.for_each([ext](const sol::object& name, const sol::object& callback) {
-                if (name.is<std::string>() && callback.is<LuaUtil::Callback>())
-                    ext->setCallback(name.as<std::string>(), callback.as<LuaUtil::Callback>());
+                if (name.is<std::string>() && LuaUtil::Callback::isLuaCallback(callback))
+                    ext->setCallback(name.as<std::string>(), LuaUtil::Callback::fromLua(callback));
                 else if (!name.is<std::string>())
                     Log(Debug::Warning) << "UI event key must be a string";
-                else if (!callback.is<LuaUtil::Callback>())
+                else
                     Log(Debug::Warning) << "UI event handler for key \"" << name.as<std::string>()
                                         << "\" must be an openmw.async.callback";
             });