// This file is distributed under the BSD License.
// See "license.txt" for details.
// Copyright 2009-2012, Jonathan Turner (jonathan@emptycrate.com)
// Copyright 2009-2017, Jason Turner (jason@emptycrate.com)
// http://www.chaiscript.com

#ifndef CHAISCRIPT_POSIX_HPP_
#define CHAISCRIPT_POSIX_HPP_

namespace chaiscript
{
  namespace detail
  {
    struct Loadable_Module
    {
      struct DLModule
      {
        explicit DLModule(const std::string &t_filename)
          : m_data(dlopen(t_filename.c_str(), RTLD_NOW))
        {
          if (m_data == nullptr)
          {
            throw chaiscript::exception::load_module_error(dlerror());
          }
        }

        DLModule(DLModule &&) = default;
        DLModule &operator=(DLModule &&) = default;
        DLModule(const DLModule &) = delete;
        DLModule &operator=(const DLModule &) = delete;

        ~DLModule()
        {
          dlclose(m_data);
        }

        void *m_data;
      };

      template<typename T>
        struct DLSym
        {
          DLSym(DLModule &t_mod, const std::string &t_symbol)
            : m_symbol(cast_symbol(dlsym(t_mod.m_data, t_symbol.c_str())))
          {
            if (!m_symbol)
            {
              throw chaiscript::exception::load_module_error(dlerror());
            }
          }

          static T cast_symbol(void *p)
          {
            union cast_union
            {
              T func_ptr;
              void *in_ptr;
            };

            cast_union c;
            c.in_ptr = p;
            return c.func_ptr;
          }

          T m_symbol;
        };

      Loadable_Module(const std::string &t_module_name, const std::string &t_filename)
        : m_dlmodule(t_filename), m_func(m_dlmodule, "create_chaiscript_module_" + t_module_name),
        m_moduleptr(m_func.m_symbol())
      {
      }

      DLModule m_dlmodule;
      DLSym<Create_Module_Func> m_func;
      ModulePtr m_moduleptr;
    };
  }
}
#endif