#!/usr/bin/r -t
#
# Copyright (C) 2009 - 2010	Romain Francois
#
# This file is part of Rcpp.
#
# Rcpp is free software: you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 2 of the License, or
# (at your option) any later version.
#
# Rcpp is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Rcpp.  If not, see <http://www.gnu.org/licenses/>.

test.XPtr <- function(){
	
	funx <- cxxfunction(signature(), '
		/* creating a pointer to a vector<int> */
		std::vector<int>* v = new std::vector<int> ;
		v->push_back( 1 ) ;
		v->push_back( 2 ) ;
		
		/* wrap the pointer as an external pointer */
		/* this automatically protected the external pointer from R garbage 
		   collection until p goes out of scope. */
		Rcpp::XPtr< std::vector<int> > p(v, true) ;
		
		/* return it back to R, since p goes out of scope after the return 
		   the external pointer is no more protected by p, but it gets 
		   protected by being on the R side */
		return( p ) ;
	', plugin = "Rcpp" )
	xp <- funx()
	checkEquals( typeof( xp ), "externalptr", 
		msg = "checking external pointer creation" )
	
	# passing the pointer back to C++
	funx <- cxxfunction(signature(x = "externalptr" ), '
		/* wrapping x as smart external pointer */
		/* The SEXP based constructor does not protect the SEXP from 
		   garbage collection automatically, it is already protected 
		   because it comes from the R side, however if you want to keep 
		   the Rcpp::XPtr object on the C(++) side
		   and return something else to R, you need to protect the external
		   pointer, by using the protect member function */
		Rcpp::XPtr< std::vector<int> > p(x) ;
		
		/* just return the front of the vector as a SEXP */
		return( Rcpp::wrap( p->front() ) ) ;
	', plugin = "Rcpp" )
	front <- funx(xp)
	checkEquals( front, 1L, msg = "check usage of external pointer" )
}