V-Gears/lib/luabind/src/object_rep.cpp

// Copyright (c) 2003 Daniel Wallin and Arvid Norberg

// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:

// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
// ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
// TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
// PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
// SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR
// ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
// ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE
// OR OTHER DEALINGS IN THE SOFTWARE.

#define LUABIND_BUILDING

#include <luabind/detail/object_rep.hpp>
#include <luabind/detail/class_rep.hpp>

namespace luabind { namespace detail
{

	// dest is a function that is called to delete the c++ object this struct holds
	object_rep::object_rep(instance_holder* instance, class_rep* crep)
		: m_instance(instance)
		, m_classrep(crep)
		, m_dependency_cnt(0)
	{}

	object_rep::~object_rep()
	{
        if (!m_instance)
            return;
        m_instance->~instance_holder();
        deallocate(m_instance);
	}

	void object_rep::add_dependency(lua_State* L, int index)
	{
        assert(m_dependency_cnt < sizeof(object_rep));

        void* key = (char*)this + m_dependency_cnt;

        lua_pushlightuserdata(L, key);
        lua_pushvalue(L, index);
        lua_rawset(L, LUA_REGISTRYINDEX);

        ++m_dependency_cnt;
	}

    void object_rep::release_dependency_refs(lua_State* L)
    {
        for (std::size_t i = 0; i < m_dependency_cnt; ++i)
        {
            void* key = (char*)this + i;
            lua_pushlightuserdata(L, key);
            lua_pushnil(L);
            lua_rawset(L, LUA_REGISTRYINDEX);
        }
    }

    int destroy_instance(lua_State* L)
    {
        object_rep* instance = static_cast<object_rep*>(lua_touserdata(L, 1));

        lua_pushstring(L, "__finalize");
        lua_gettable(L, 1);

        if (lua_isnil(L, -1))
        {
            lua_pop(L, 1);
        }
        else
        {
            lua_pushvalue(L, 1);
            lua_call(L, 1, 0);
        }

        instance->release_dependency_refs(L);
        instance->~object_rep();
        return 0;
    }

    namespace
    {

      int set_instance_value(lua_State* L)
      {
          lua_getfenv(L, 1);
          lua_pushvalue(L, 2);
          lua_rawget(L, -2);

          if (lua_isnil(L, -1) && lua_getmetatable(L, -2))
          {
              lua_pushvalue(L, 2);
              lua_rawget(L, -2);
              lua_replace(L, -3);
              lua_pop(L, 1);
          }

          if (lua_tocfunction(L, -1) == &property_tag)
          {
              // this member is a property, extract the "set" function and call it.
              lua_getupvalue(L, -1, 2);

              if (lua_isnil(L, -1))
              {
                  lua_pushfstring(L, "property '%s' is read only", lua_tostring(L, 2));
                  lua_error(L);
              }

              lua_pushvalue(L, 1);
              lua_pushvalue(L, 3);
              lua_call(L, 2, 0);
              return 0;
          }

          lua_pop(L, 1);

          if (!lua_getmetatable(L, 4))
          {
              lua_newtable(L);
              lua_pushvalue(L, -1);
              lua_setfenv(L, 1);
              lua_pushvalue(L, 4);
              lua_setmetatable(L, -2);
          }
          else
          {
              lua_pop(L, 1);
          }

          lua_pushvalue(L, 2);
          lua_pushvalue(L, 3);
          lua_rawset(L, -3);

          return 0;
      }

      int get_instance_value(lua_State* L)
      {
          lua_getfenv(L, 1);
          lua_pushvalue(L, 2);
          lua_rawget(L, -2);

          if (lua_isnil(L, -1) && lua_getmetatable(L, -2))
          {
              lua_pushvalue(L, 2);
              lua_rawget(L, -2);
          }

          if (lua_tocfunction(L, -1) == &property_tag)
          {
              // this member is a property, extract the "get" function and call it.
              lua_getupvalue(L, -1, 1);
              lua_pushvalue(L, 1);
              lua_call(L, 1, 1);
          }

          return 1;
      }

      int dispatch_operator(lua_State* L)
      {
          for (int i = 0; i < 2; ++i)
          {
              if (get_instance(L, 1 + i))
              {
                  int nargs = lua_gettop(L);

                  lua_pushvalue(L, lua_upvalueindex(1));
                  lua_gettable(L, 1 + i);

                  if (lua_isnil(L, -1))
                  {
                      lua_pop(L, 1);
                      continue;
                  }

                  lua_insert(L, 1); // move the function to the bottom

                  nargs = lua_toboolean(L, lua_upvalueindex(2)) ? 1 : nargs;

                  if (lua_toboolean(L, lua_upvalueindex(2))) // remove trailing nil
                  lua_remove(L, 3);

                  lua_call(L, nargs, 1);
                  return 1;
              }
          }

          lua_pop(L, lua_gettop(L));
          lua_pushstring(L, "No such operator defined");
          lua_error(L);

          return 0;
      }

    } // namespace unnamed

    LUABIND_API void push_instance_metatable(lua_State* L)
    {
        lua_newtable(L);

        // This is used as a tag to determine if a userdata is a luabind
        // instance. We use a numeric key and a cclosure for fast comparision.
        lua_pushnumber(L, 1);
        lua_pushcclosure(L, get_instance_value, 0);
        lua_rawset(L, -3);

        lua_pushcclosure(L, destroy_instance, 0);
        lua_setfield(L, -2, "__gc");

        lua_pushcclosure(L, get_instance_value, 0);
        lua_setfield(L, -2, "__index");

        lua_pushcclosure(L, set_instance_value, 0);
        lua_setfield(L, -2, "__newindex");

        for (int op = 0; op < number_of_operators; ++op)
        {
            lua_pushstring(L, get_operator_name(op));
            lua_pushvalue(L, -1);
            lua_pushboolean(L, op == op_unm || op == op_len);
            lua_pushcclosure(L, &dispatch_operator, 2);
            lua_settable(L, -3);
        }
    }

    LUABIND_API object_rep* get_instance(lua_State* L, int index)
    {
        object_rep* result = static_cast<object_rep*>(lua_touserdata(L, index));

        if (!result || !lua_getmetatable(L, index))
            return 0;

        lua_rawgeti(L, -1, 1);

        if (lua_tocfunction(L, -1) != &get_instance_value)
            result = 0;

        lua_pop(L, 2);

        return result;
    }

    LUABIND_API object_rep* push_new_instance(lua_State* L, class_rep* cls)
    {
        void* storage = lua_newuserdata(L, sizeof(object_rep));
        object_rep* result = new (storage) object_rep(0, cls);
        cls->get_table(L);
        lua_setfenv(L, -2);
        lua_rawgeti(L, LUA_REGISTRYINDEX, cls->metatable_ref());
        lua_setmetatable(L, -2);
        return result;
    }

}}