revised scope documentation and added smart pointer documentation.

[luabind.git] / luabind / detail / class_rep.hpp

// 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_CLASS_REP_HPP_INCLUDED
#define LUABIND_CLASS_REP_HPP_INCLUDED

#include <boost/limits.hpp>
#include <boost/preprocessor/repetition/enum_params_with_a_default.hpp>

#include <utility>

#include <luabind/config.hpp>
#include <luabind/detail/object_rep.hpp>
#include <luabind/detail/construct_rep.hpp>
#include <luabind/detail/method_rep.hpp>
#include <luabind/detail/garbage_collector.hpp>
#include <luabind/detail/operator_id.hpp>
#include <luabind/detail/signature_match.hpp>
#include <luabind/detail/class_registry.hpp>
#include <luabind/detail/find_best_match.hpp>
#include <luabind/detail/get_overload_signature.hpp>
#include <luabind/detail/error.hpp>

namespace luabind
{

        template<BOOST_PP_ENUM_PARAMS_WITH_A_DEFAULT(LUABIND_MAX_BASES, class A, detail::null_type)>
        struct bases {};
        typedef bases<detail::null_type> no_bases;

        struct class_base;

}

namespace luabind { namespace detail
{
        std::string stack_content_by_name(lua_State* L, int start_index);
        int construct_lua_class_callback(lua_State* L);

        // this is class-specific information, poor man's vtable
        // this is allocated statically (removed by the compiler)
        // a pointer to this structure is stored in the lua tables'
        // metatable with the name __classrep
        // it is used when matching parameters to function calls
        // to determine possible implicit casts
        // it is also used when finding the best match for overloaded
        // methods

        class class_rep
        {
        friend struct luabind::class_base;
        friend int super_callback(lua_State*);
//TODO: avoid the lua-prefix
        friend int lua_class_gettable(lua_State*);
        friend int lua_class_settable(lua_State*);
        friend int static_class_gettable(lua_State*);
        public:

                enum class_type
                {
                        cpp_class = 0,
                        lua_class = 1
                };

                // destructor is a lua callback function that is hooked as garbage collector event on every instance
                // of this class (including those that is not owned by lua). It gets an object_rep as argument
                // on the lua stack. It should delete the object pointed to by object_rep::ptr if object_pre::flags
                // is object_rep::owner (which means that lua owns the object)

                // EXPECTS THE TOP VALUE ON THE LUA STACK TO
                // BE THE USER DATA WHERE THIS CLASS IS BEING
                // INSTANTIATED!
                class_rep(LUABIND_TYPE_INFO t
                        , const char* name
                        , lua_State* L
                        , void(*destructor)(void*)
                        , LUABIND_TYPE_INFO held_t
                        , LUABIND_TYPE_INFO held_const_t
                        , void*(*extractor)(void*)
                        , void(*construct_held_type)(void*,void*)
                        , int held_type_size
                        , int held_type_alignment);

                // used when creating a lua class
                // EXPECTS THE TOP VALUE ON THE LUA STACK TO
                // BE THE USER DATA WHERE THIS CLASS IS BEING
                // INSTANTIATED!
                class_rep(lua_State* L, const char* name);

                ~class_rep();

                std::pair<void*,void*> allocate(lua_State* L) const;

                // called from the metamethod for __index
                // the object pointer is passed on the lua stack
                int gettable(lua_State* L);

                // called from the metamethod for __newindex
                // the object pointer is passed on the lua stack
                bool settable(lua_State* L);

                // this is called as __index metamethod on every instance of this class
                static int gettable_dispatcher(lua_State* L);

                // this is called as __newindex metamethod on every instance of this class
                static int settable_dispatcher(lua_State* L);
                static int operator_dispatcher(lua_State* L);

                // this is called as metamethod __call on the class_rep.
                static int constructor_dispatcher(lua_State* L);

//              static int implicit_cast(const class_rep* from, const class_rep* to, int& pointer_offset);

                // the functions dispatcher assumes the following:
                // there is one upvalue that points to the method_rep that this dispatcher is to call
                // the first parameter on the lua stack is an object_rep that points to the object the
                // call is being made on
                static int function_dispatcher(lua_State* L);

                struct base_info
                {
                        int pointer_offset; // the offset added to the pointer to obtain a basepointer (due to multiple-inheritance)
                        class_rep* base;
                };


                void add_base_class(const base_info& binfo);

                inline const std::vector<base_info>& bases() const throw() { return m_bases; }

                inline void set_type(LUABIND_TYPE_INFO t) { m_type = t; }
                inline LUABIND_TYPE_INFO type() const throw() { return m_type; }
                inline LUABIND_TYPE_INFO holder_type() const throw() { return m_held_type; }
                inline LUABIND_TYPE_INFO const_holder_type() const throw() { return m_const_holder_type; }

                inline const char* name() const throw() { return m_name; }

                // the lua reference to this class_rep
                inline int self_ref() const throw() { return m_self_ref; }
                // the lua reference to the metatable for this class' instances
                inline int metatable_ref() const throw() { return m_instance_metatable; }
                inline int table_ref() const { return m_table_ref; }

                inline void(*destructor() const)(void*) { return m_destructor; }
                inline void*(*extract_ptr() const)(void*) { return m_extract_underlying_fun; }

                inline class_type get_class_type() const { return m_class_type; }

                void add_static_constant(const char* name, int val);

                static int super_callback(lua_State* L);

                static int lua_settable_dispatcher(lua_State* L);
                static int construct_lua_class_callback(lua_State* L);

                // called from the metamethod for __index
                // obj is the object pointer
                static int lua_class_gettable(lua_State* L);

                // called from the metamethod for __newindex
                // obj is the object pointer
                static int lua_class_settable(lua_State* L);

                static int static_class_gettable(lua_State* L);

                void* convert_to(LUABIND_TYPE_INFO target_type, const object_rep* obj) const;

        private:

                // this is a pointer to the type_info structure for
                // this type
                // warning: this may be a problem when using dll:s, since
                // typeid() may actually return different pointers for the same
                // type.
                LUABIND_TYPE_INFO m_type;
                LUABIND_TYPE_INFO m_held_type;
                LUABIND_TYPE_INFO m_const_holder_type;

                // this function pointer is used if the type is held by
                // a smart pointer. This function takes the type we are holding
                // (the held_type, the smart pointer) and extracts the actual
                // pointer.
                typedef void*(*extract_ptr_t)(void*);
                extract_ptr_t m_extract_underlying_fun;

                // this function is used to construct the held_type
                // (the smart pointer). The arguments are the memory
                // in which it should be constructed (with placement new)
                // and the raw pointer that should be wrapped in the
                // smart pointer
                typedef void(*construct_held_type_t)(void*,void*);
                construct_held_type_t m_held_type_constructor;

                // this is the size of the userdata chunk
                // for each object_rep of this class. We
                // need this since held_types are constructed
                // in the same memory (to avoid fragmentation)
                int m_userdata_size;
                int m_userdata_alignment;

                // a list of info for every class this class derives from
                // the information stored here is sufficient to do
                // type casts to the base classes
                std::vector<base_info> m_bases;

                // the class' name (as given when registered to lua with class_)
                const char* m_name;

                // contains signatures and construction functions
                // for all constructors
                construct_rep m_constructor;

                // a reference to this structure itself. Since this struct
                // is kept inside lua (to let lua collect it when lua_close()
                // is called) we need to lock it to prevent collection.
                // the actual reference is not currently used.
                int m_self_ref;

                // a reference to the lua table that represents this class
                // (only used if it is a lua class)
                int m_table_ref;

                // the type of this class.. determines if it's written in c++ or lua
                class_type m_class_type;

                // this is a lua reference that points to the lua table
                // that is to be used as meta table for all instances
                // of this class.
                int m_instance_metatable;

                // ***** the maps below contains all members in this class *****

                // maps method names to a structure with more
                // information about that method.
                // that struct contains the function-signatures
                // for every overload
                std::map<const char*, method_rep, ltstr> m_methods;

#ifndef LUABIND_DONT_COPY_STRINGS
                // this is where the strings that the maps contains
                // pointer to are kept. To make sure they are destructed.
                std::vector<char*> m_strings;
#endif

                struct callback
                {
                        boost::function2<int, lua_State*, int> func;
                        int pointer_offset;
                };

                // datamembers, some members may be readonly, and
                // only have a getter function
                std::map<const char*, callback, ltstr> m_getters;
                std::map<const char*, callback, ltstr> m_setters;

                struct operator_callback: public overload_rep_base
                {
                        inline void set_fun(int (*f)(lua_State*)) { func = f; }
                        inline int call(lua_State* L) { return func(L); }
                        inline void set_arity(int arity) { m_arity = arity; }

                private:

                        int(*func)(lua_State*);
                };

                std::vector<operator_callback> m_operators[number_of_operators]; // the operators in lua

                void(*m_destructor)(void*);

                std::map<const char*, int, ltstr> m_static_constants;
        };

        bool is_class_rep(lua_State* L, int index);

}}

#endif // LUABIND_CLASS_REP_HPP_INCLUDED