libs/scope_exit/test/world_checkpoint_all.cpp
// Copyright (C) 2006-2009, 2012 Alexander Nasonov
// Copyright (C) 2012 Lorenzo Caminiti
// Distributed under the Boost Software License, Version 1.0
// (see accompanying file LICENSE_1_0.txt or a copy at
// http://www.boost.org/LICENSE_1_0.txt)
// Home at http://www.boost.org/libs/scope_exit
#include <boost/config.hpp>
#if defined(BOOST_NO_CXX11_LAMBDAS)
# error "lambda functions required"
#elif defined(BOOST_NO_CXX11_VARIADIC_MACROS)
# error "variadic macros required"
#else
#include <boost/scope_exit.hpp>
#include <boost/foreach.hpp>
#include <boost/typeof/typeof.hpp>
#include <boost/typeof/std/vector.hpp>
#include BOOST_TYPEOF_INCREMENT_REGISTRATION_GROUP()
#include <boost/detail/lightweight_test.hpp>
#include <vector>
#include <iostream>
#include <sstream>
struct person {
typedef unsigned int id_t;
typedef unsigned int evolution_t;
id_t id;
evolution_t evolution;
person(void) : id(0), evolution(0) {}
friend std::ostream& operator<<(std::ostream& o, person const& p) {
return o << "person(" << p.id << ", " << p.evolution << ")";
}
};
BOOST_TYPEOF_REGISTER_TYPE(person)
struct world {
world(void) : next_id_(1) {}
void add_person(person const& a_person);
friend std::ostream& operator<<(std::ostream& o, world const& w) {
o << "world(" << w.next_id_ << ", {";
BOOST_FOREACH(person const& p, w.persons_) {
o << " " << p << ", ";
}
return o << "})";
}
private:
person::id_t next_id_;
std::vector<person> persons_;
};
BOOST_TYPEOF_REGISTER_TYPE(world)
//[world_checkpoint_all
void world::add_person(person const& a_person) {
persons_.push_back(a_person);
// This block must be no-throw.
person& p = persons_.back();
person::evolution_t checkpoint = p.evolution;
// Capture all by reference `&`, but `checkpoint` and `this` (C++11 only).
BOOST_SCOPE_EXIT_ALL(&, checkpoint, this) { // Use `this` (not `this_`).
if(checkpoint == p.evolution) this->persons_.pop_back();
}; // Use `;` (not `SCOPE_EXIT_END`).
// ...
checkpoint = ++p.evolution;
// Assign new identifier to the person.
person::id_t const prev_id = p.id;
p.id = next_id_++;
// Capture all by value `=`, but `p` (C++11 only).
BOOST_SCOPE_EXIT_ALL(=, &p) {
if(checkpoint == p.evolution) {
this->next_id_ = p.id;
p.id = prev_id;
}
};
// ...
checkpoint = ++p.evolution;
}
//]
int main(void) {
person adam, eva;
std::ostringstream oss;
oss << adam;
std::cout << oss.str() << std::endl;
BOOST_TEST(oss.str() == "person(0, 0)");
oss.str("");
oss << eva;
std::cout << oss.str() << std::endl;
BOOST_TEST(oss.str() == "person(0, 0)");
world w;
w.add_person(adam);
w.add_person(eva);
oss.str("");
oss << w;
std::cout << oss.str() << std::endl;
BOOST_TEST(oss.str() == "world(3, { person(1, 2), person(2, 2), })");
return boost::report_errors();
}
#endif // lambda functions and variadic macros