//----------------------------------------------------------------//
// userdata -> memberTable -> refTable -> interfaceTable
// userdata is the object
// memberTable is for ad hoc members added by the scripter
// refTable is for ad hoc mambers added by the engine
// interfaceTable is the 'class' table - methods and constants
// __index looks in membertTable then *skips* refTable to fall back on interfaceTable
void MOAILuaObject::BindToLua ( MOAILuaState& state ) {
assert ( !this->mUserdata );
if ( MOAILuaRuntime::IsValid ()) {
MOAILuaRuntime::Get ().RegisterObject ( state, *this );
}
MOAILuaClass* type = this->GetLuaClass ();
assert ( type );
// both singletons and instances may be bound to a userdata
state.PushPtrUserData ( this ); // userdata
// for now, singletons are just userdata with no add'l metatables
// so only build the metatable stack if we're *not* a singleton
if ( !type->IsSingleton ()) {
// instances get the 'full stack' of metatables
lua_newtable ( state ); // ref table
lua_newtable ( state ); // member table
type->PushInterfaceTable ( state ); // interface table
this->MakeLuaBinding ( state );
}
// and take a weak ref back to the userdata
this->mUserdata.SetRef ( state, -1 );
assert ( !lua_isnil ( state, -1 ));
// NOTE: we have to do this *after* mUserdata has been initialized as LuaRetain calls PushLuaUserdata
// which in turn calls BindToLua if there is no mUserdata...
if ( type->IsSingleton ()) {
this->LuaRetain ( this ); // create a circular reference to 'pin' the userdata
}
}
//----------------------------------------------------------------//
void MOAILuaObject::BindToLuaWithTable ( MOAILuaState& state ) {
assert ( !this->mUserdata );
assert ( state.IsType ( -1, LUA_TTABLE ));
MOAILuaClass* type = this->GetLuaClass ();
assert ( type );
// create and initialize a new userdata
state.PushPtrUserData ( this );
// create and initialize the private table
lua_newtable ( state );
// set the ref to the private table
lua_pushvalue ( state, -3 );
lua_setfield ( state, -2, LUA_MEMBER_TABLE_NAME );
// initialize the private table
lua_pushcfunction ( state, MOAILuaObject::_gc );
lua_setfield ( state, -2, "__gc" );
lua_pushcfunction ( state, MOAILuaObject::_tostring );
lua_setfield ( state, -2, "__tostring" );
lua_pushcfunction ( state, MOAILuaObject::_index );
lua_setfield ( state, -2, "__index" );
lua_pushcfunction ( state, MOAILuaObject::_newindex );
lua_setfield ( state, -2, "__newindex" );
// make the interface table the instance table's meta
type->PushInterfaceTable ( state );
lua_setmetatable ( state, -2 );
// grab a ref to the instance table; attach it to the userdata
this->mInstanceTable = state.GetWeakRef ( -1 );
lua_setmetatable ( state, -2 );
// and take a ref back to the userdata
if ( this->GetRefCount () == 0 ) {
this->mUserdata.SetWeakRef ( state, -1 );
}
else {
this->mUserdata.SetStrongRef ( state, -1 );
}
// overwrite the member table
lua_replace ( state, -2 );
assert ( !lua_isnil ( state, -1 ));
}
//----------------------------------------------------------------//
void MOAILuaObject::BindToLua ( MOAILuaState& state ) {
assert ( !this->mUserdata );
MOAILuaClass* type = this->GetLuaClass ();
assert ( type );
// create and initialize a new userdata
state.PushPtrUserData ( this );
// create and initialize the member table
lua_newtable ( state );
lua_pushvalue ( state, -1 );
lua_setfield ( state, -2, "__index" );
lua_pushvalue ( state, -1 );
lua_setfield ( state, -2, "__newindex" );
lua_pushcfunction ( state, MOAILuaObject::_gc );
lua_setfield ( state, -2, "__gc" );
lua_pushcfunction ( state, MOAILuaObject::_tostring );
lua_setfield ( state, -2, "__tostring" );
// attach the member table to the userdata
lua_pushvalue ( state, -1 );
lua_setmetatable ( state, -3 );
// grab a ref to the member table
this->mMemberTable = state.GetWeakRef ( -1 );
// stack:
// -1: member table
// -2: userdata
// create an empty ref table and attach it to the member table
lua_newtable ( state );
lua_pushvalue ( state, -1 );
lua_setmetatable ( state, -3 );
// stack:
// -1: ref table
// -2: member table
// -3: userdata
// push the interface table and attach it to the ref table
type->PushInterfaceTable ( state );
lua_pushvalue ( state, -1 );
lua_setmetatable ( state, -3 );
// stack:
// -1: interface table
// -2: ref table
// -3: member table
// -4: userdata
// use the interface table as the ref table's __index
lua_setfield ( state, -2, "__index" );
// stack:
// -1: ref table
// -2: member table
// -3: userdata
lua_pop ( state, 2 );
// stack:
// -1: userdata
// and take a ref back to the userdata
if ( this->GetRefCount () == 0 ) {
this->mUserdata.SetWeakRef ( state, -1 );
}
else {
this->mUserdata.SetStrongRef ( state, -1 );
}
assert ( !lua_isnil ( state, -1 ));
}