Method PreCall

Plugins/UnLua/Source/UnLua/Private/ReflectionUtils/FunctionDesc.cpp:394–473

* Prepare values of properties for the UFunction */

 * Prepare values of properties for the UFunction
 */
void* FFunctionDesc::PreCall(lua_State* L, int32 NumParams, int32 FirstParamIndex, FFlagArray& CleanupFlags, void* Userdata)
{
#if ENABLE_PERSISTENT_PARAM_BUFFER
    void* Params = Buffer;
#else
    void* Params = Function->ParmsSize > 0 ? FMemory::Malloc(Function->ParmsSize, 16) : nullptr;
#endif

#if !SUPPORTS_RPC_CALL
    ++NumCalls;
#endif

    int32 ParamIndex = 0;
    for (int32 i = 0; i < Properties.Num(); ++i)
    {
        const auto& Property = Properties[i];
        Property->InitializeValue(Params);
        if (i == LatentPropertyIndex)
        {
            const int32 ThreadRef = *((int32*)Userdata);
            void* ContainerPtr = (uint8*)Params;// + Property->GetOffset();
            if(lua_type(L, FirstParamIndex + ParamIndex) == LUA_TUSERDATA)
            {
                // custom latent action info
                FLatentActionInfo Info = UnLua::Get<FLatentActionInfo>(L, FirstParamIndex + ParamIndex, UnLua::TType<FLatentActionInfo>());
                Property->CopyValue(ContainerPtr, &Info);
                continue;
            }

            // bind a callback to the latent function
            auto& Env = UnLua::FLuaEnv::FindEnvChecked(L);
            FLatentActionInfo LatentActionInfo(ThreadRef, GetTypeHash(FGuid::NewGuid()), TEXT("OnLatentActionCompleted"), (Env.GetManager()));
            Property->CopyValue(ContainerPtr, &LatentActionInfo);
            continue;
        }
        if (i == ReturnPropertyIndex)
        {
            CleanupFlags[i] = ParamIndex >= NumParams || !Property->CopyBack(L, FirstParamIndex + ParamIndex, Params);
            continue;
        }
        if (ParamIndex < NumParams)
        {   
#if ENABLE_TYPE_CHECK == 1
            FString ErrorMsg = "";
            if (!Property->CheckPropertyType(L, FirstParamIndex + ParamIndex, ErrorMsg))
            {
                UNLUA_LOGERROR(L, LogUnLua, Warning, TEXT("Invalid parameter type calling ufunction : %s,parameter : %d, error msg : %s"), *FuncName, ParamIndex, *ErrorMsg);
            }
#endif
            CleanupFlags[i] = Property->SetValue(L, Params, FirstParamIndex + ParamIndex, false);
        }
        else if (!Property->IsOutParameter())
        {
            if (DefaultParams)
            {
                // set value for default parameter
                IParamValue **DefaultValue = DefaultParams->Parameters.Find(Property->GetProperty()->GetFName());
                if (DefaultValue)