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/config.hpp> |
10 | #ifdef BOOST_NO_CXX11_VARIADIC_MACROS |
11 | # error "variadic macros required" |
12 | #else |
13 | |
14 | #include <boost/scope_exit.hpp> |
15 | #include <boost/foreach.hpp> |
16 | #include <boost/typeof/typeof.hpp> |
17 | #include <boost/typeof/std/vector.hpp> |
18 | #include BOOST_TYPEOF_INCREMENT_REGISTRATION_GROUP() |
19 | #include <boost/detail/lightweight_test.hpp> |
20 | #include <vector> |
21 | #include <iostream> |
22 | #include <sstream> |
23 | |
24 | struct person { |
25 | typedef unsigned int id_t; |
26 | typedef unsigned int evolution_t; |
27 | |
28 | id_t id; |
29 | evolution_t evolution; |
30 | |
31 | person(void) : id(0), evolution(0) {} |
32 | |
33 | friend std::ostream& operator<<(std::ostream& o, person const& p) { |
34 | return o << "person(" << p.id << ", " << p.evolution << ")" ; |
35 | } |
36 | }; |
37 | BOOST_TYPEOF_REGISTER_TYPE(person) |
38 | |
39 | struct world { |
40 | world(void) : next_id_(1) {} |
41 | void add_person(person const& a_person); |
42 | |
43 | friend std::ostream& operator<<(std::ostream& o, world const& w) { |
44 | o << "world(" << w.next_id_ << ", {" ; |
45 | BOOST_FOREACH(person const& p, w.persons_) { |
46 | o << " " << p << ", " ; |
47 | } |
48 | return o << "})" ; |
49 | } |
50 | |
51 | private: |
52 | person::id_t next_id_; |
53 | std::vector<person> persons_; |
54 | }; |
55 | BOOST_TYPEOF_REGISTER_TYPE(world) |
56 | |
57 | //[world_checkpoint |
58 | void world::add_person(person const& a_person) { |
59 | persons_.push_back(x: a_person); |
60 | |
61 | // This block must be no-throw. |
62 | person& p = persons_.back(); |
63 | person::evolution_t checkpoint = p.evolution; |
64 | BOOST_SCOPE_EXIT(checkpoint, &p, &persons_) { |
65 | if(checkpoint == p.evolution) persons_.pop_back(); |
66 | } BOOST_SCOPE_EXIT_END |
67 | |
68 | // ... |
69 | |
70 | checkpoint = ++p.evolution; |
71 | |
72 | // Assign new identifier to the person. |
73 | person::id_t const prev_id = p.id; |
74 | p.id = next_id_++; |
75 | BOOST_SCOPE_EXIT(checkpoint, &p, &next_id_, prev_id) { |
76 | if(checkpoint == p.evolution) { |
77 | next_id_ = p.id; |
78 | p.id = prev_id; |
79 | } |
80 | } BOOST_SCOPE_EXIT_END |
81 | |
82 | // ... |
83 | |
84 | checkpoint = ++p.evolution; |
85 | } |
86 | //] |
87 | |
88 | int main(void) { |
89 | person adam, eva; |
90 | std::ostringstream oss; |
91 | oss << adam; |
92 | std::cout << oss.str() << std::endl; |
93 | BOOST_TEST(oss.str() == "person(0, 0)" ); |
94 | |
95 | oss.str(s: "" ); |
96 | oss << eva; |
97 | std::cout << oss.str() << std::endl; |
98 | BOOST_TEST(oss.str() == "person(0, 0)" ); |
99 | |
100 | world w; |
101 | w.add_person(a_person: adam); |
102 | w.add_person(a_person: eva); |
103 | oss.str(s: "" ); |
104 | oss << w; |
105 | std::cout << oss.str() << std::endl; |
106 | BOOST_TEST(oss.str() == "world(3, { person(1, 2), person(2, 2), })" ); |
107 | |
108 | return boost::report_errors(); |
109 | } |
110 | |
111 | #endif // variadic macros |
112 | |
113 | |