object_rep.hpp

国外魔兽世界-NOPserver源码,2004年版

// 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.


#ifndef LUABIND_OBJECT_REP_HPP_INCLUDED
#define LUABIND_OBJECT_REP_HPP_INCLUDED

#include <luabind/config.hpp>
#include <luabind/detail/ref.hpp>

namespace luabind { namespace detail
{
	class class_rep;

	void finalize(lua_State* L, class_rep* crep);

	// this class is allocated inside lua for each pointer.
	// it contains the actual c++ object-pointer.
	// it also tells if it is const or not.
	class object_rep
	{
	public:
		enum { constant = 1, owner = 2, smart_pointer = 4, lua_class = 8, call_super = 16 };

		// dest is a function that is called to delete the c++ object this struct holds
		object_rep(void* obj, class_rep* crep, int flags, void(*dest)(void*)):
			m_object(obj),
			m_classrep(crep),
			m_flags(flags),
			m_lua_table_ref(LUA_NOREF),
			m_destructor(dest),
			m_dependency_cnt(1),
			m_dependency_ref(LUA_NOREF)
		{
			// if the object is owned by lua, a valid destructor must be given
			assert((((m_flags & owner) && dest) || !(m_flags & owner)) && "internal error, please report");

			// an object can't be collected if it's const
			// if it has a holder type, the holder can be collected
//			assert((!((m_flags & constant) && (m_flags & owner))) && "internal error, please report");
		}

		object_rep(class_rep* crep, int flags, int table_ref)
			: m_object(0)
			, m_classrep(crep)
			, m_flags(flags)
			, m_lua_table_ref(table_ref)
			, m_destructor(0)
			, m_dependency_cnt(1)
			, m_dependency_ref(LUA_NOREF)
		{
		}

		~object_rep() 
		{ 
			if (m_flags & owner && m_destructor) m_destructor(m_object);
		}

		void* ptr() const throw() { return m_object; }

		void* ptr(int pointer_offset) const throw()
		{
			return reinterpret_cast<char*>(m_object) + pointer_offset;
		}

		const class_rep* crep() const throw() { return m_classrep; }
		class_rep* crep() throw() { return m_classrep; }
		int flags() const throw() { return m_flags; }
		void set_flags(int flags) { m_flags = flags; }

		int lua_table_ref() const { return m_lua_table_ref; }

		void remove_ownership()
		{
			assert((m_flags & owner) && "cannot remove ownership of object that's not owned");
			m_flags &= ~owner;
		}

		void set_destructor(void(*ptr)(void*))
		{
			m_destructor = ptr;
		}

		void set_object(void* p) { m_object = p; }

		void add_dependency(lua_State* L, int index)
		{
			if (m_dependency_ref == LUA_NOREF)
			{
				lua_newtable(L);
				m_dependency_ref = detail::ref(L);
			}

			detail::getref(L, m_dependency_ref);
			lua_pushvalue(L, index);
			lua_rawseti(L, -2, m_dependency_cnt);
			lua_pop(L, 1);
			++m_dependency_cnt;
		}

		void release_refs(lua_State* L)
		{
			if (m_dependency_ref != LUA_NOREF) detail::unref(L, m_dependency_ref);
			if (m_lua_table_ref != LUA_NOREF) detail::unref(L, m_lua_table_ref); // correct?
		}

		static int garbage_collector(lua_State* L)
		{
			object_rep* obj = static_cast<object_rep*>(lua_touserdata(L, -1));

			finalize(L, obj->crep());

			obj->release_refs(L);
			obj->~object_rep();
			return 0;
		}

	private:

		void* m_object; // the c++ object pointer / if lua class, this is a pointer the the instance of the
									// c++ base or 0.
		class_rep* m_classrep; // the class information about this object's type
		int m_flags;
		int m_lua_table_ref; // reference to lua table if this is a lua class
		void(*m_destructor)(void*); // this could be in class_rep? it can't: see intrusive_ptr
		int m_dependency_cnt; // counts dependencies
		int m_dependency_ref; // reference to lua table holding dependency references
	};

	template<class T>
	struct delete_s
	{
		static void apply(void* ptr)
		{
			delete static_cast<T*>(ptr);
		}
	};

	template<class T>
	struct destruct_only_s
	{
		static void apply(void* ptr)
		{
			static_cast<T*>(ptr)->~T();
		}
	};


	inline object_rep* is_class_object(lua_State* L, int index)
	{
		object_rep* obj = static_cast<detail::object_rep*>(lua_touserdata(L, index));
		if (!obj) return 0;
		if (lua_getmetatable(L, index) == 0) return 0;

		lua_pushstring(L, "__luabind_class");
		lua_gettable(L, -2);
		bool confirmation = lua_toboolean(L, -1) != 0;
		lua_pop(L, 2);
		if (!confirmation) return 0;
		return obj;

	}

}}

#endif // LUABIND_OBJECT_REP_HPP_INCLUDED