1 | |
2 | // Copyright (C) 2006-2009, 2012 Alexander Nasonov |
3 | // Copyright (C) 2012 Lorenzo Caminiti |
4 | // Distributed under the Boost Software License, Version 1.0 |
5 | // (see accompanying file LICENSE_1_0.txt or a copy at |
6 | // http://www.boost.org/LICENSE_1_0.txt) |
7 | // Home at http://www.boost.org/libs/scope_exit |
8 | |
9 | #include <boost/scope_exit.hpp> |
10 | #include <boost/foreach.hpp> |
11 | #include <boost/typeof/typeof.hpp> |
12 | #include <boost/typeof/std/vector.hpp> |
13 | #include BOOST_TYPEOF_INCREMENT_REGISTRATION_GROUP() |
14 | #include <boost/detail/lightweight_test.hpp> |
15 | #include <vector> |
16 | #include <sstream> |
17 | |
18 | struct person { |
19 | typedef unsigned int id_t; |
20 | typedef unsigned int evolution_t; |
21 | |
22 | id_t id; |
23 | evolution_t evolution; |
24 | |
25 | person(void) : id(0), evolution(0) {} |
26 | |
27 | friend std::ostream& operator<<(std::ostream& o, person const& p) { |
28 | return o << "person(" << p.id << ", " << p.evolution << ")" ; |
29 | } |
30 | }; |
31 | BOOST_TYPEOF_REGISTER_TYPE(person) |
32 | |
33 | struct world { |
34 | world(void) : next_id_(1) {} |
35 | void add_person(person const& a_person); |
36 | |
37 | friend std::ostream& operator<<(std::ostream& o, world const& w) { |
38 | o << "world(" << w.next_id_ << ", {" ; |
39 | BOOST_FOREACH(person const& p, w.persons_) { |
40 | o << " " << p << ", " ; |
41 | } |
42 | return o << "})" ; |
43 | } |
44 | |
45 | private: |
46 | person::id_t next_id_; |
47 | std::vector<person> persons_; |
48 | }; |
49 | BOOST_TYPEOF_REGISTER_TYPE(world) |
50 | |
51 | void world::add_person(person const& a_person) { |
52 | persons_.push_back(x: a_person); |
53 | |
54 | // This block must be no-throw. |
55 | person& p = persons_.back(); |
56 | person::evolution_t checkpoint = p.evolution; |
57 | BOOST_SCOPE_EXIT( (checkpoint) (&p) (&persons_) ) { |
58 | if(checkpoint == p.evolution) persons_.pop_back(); |
59 | } BOOST_SCOPE_EXIT_END |
60 | |
61 | // ... |
62 | |
63 | checkpoint = ++p.evolution; |
64 | |
65 | // Assign new identifier to the person. |
66 | person::id_t const prev_id = p.id; |
67 | p.id = next_id_++; |
68 | BOOST_SCOPE_EXIT( (checkpoint) (&p) (&next_id_) (prev_id) ) { |
69 | if(checkpoint == p.evolution) { |
70 | next_id_ = p.id; |
71 | p.id = prev_id; |
72 | } |
73 | } BOOST_SCOPE_EXIT_END |
74 | |
75 | // ... |
76 | |
77 | checkpoint = ++p.evolution; |
78 | } |
79 | |
80 | int main(void) { |
81 | person adam, eva; |
82 | std::ostringstream oss; |
83 | oss << adam; |
84 | BOOST_TEST(oss.str() == "person(0, 0)" ); |
85 | |
86 | oss.str(s: "" ); |
87 | oss << eva; |
88 | BOOST_TEST(oss.str() == "person(0, 0)" ); |
89 | |
90 | world w; |
91 | w.add_person(a_person: adam); |
92 | w.add_person(a_person: eva); |
93 | oss.str(s: "" ); |
94 | oss << w; |
95 | BOOST_TEST(oss.str() == "world(3, { person(1, 2), person(2, 2), })" ); |
96 | |
97 | return boost::report_errors(); |
98 | } |
99 | |
100 | |