1//===----------------------------------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9// UNSUPPORTED: c++03, c++11, c++14, c++17
10// UNSUPPORTED: no-localization
11// UNSUPPORTED: libcpp-has-no-experimental-syncstream
12
13// <syncstream>
14
15// template <class charT, class traits, class Allocator>
16// class basic_osyncstream;
17
18// basic_osyncstream& operator=(basic_osyncstream&& rhs);
19
20#include <syncstream>
21#include <sstream>
22#include <cassert>
23
24#include "test_macros.h"
25#include "test_allocator.h"
26
27template <class CharT, bool propagate>
28static void test() {
29 using Traits = std::char_traits<CharT>;
30 using Allocator = std::conditional_t<propagate, other_allocator<CharT>, test_allocator<CharT>>;
31 static_assert(std::allocator_traits<Allocator>::propagate_on_container_move_assignment::value == propagate);
32
33 using OS = std::basic_osyncstream<CharT, Traits, Allocator>;
34
35 std::basic_stringbuf<CharT, Traits, Allocator> base1;
36 std::basic_stringbuf<CharT, Traits, Allocator> base2;
37
38 {
39 OS out1{&base1, Allocator{42}};
40 assert(out1.get_wrapped() == &base1);
41
42 typename OS::syncbuf_type* sb1 = out1.rdbuf();
43 assert(sb1->get_wrapped() == &base1);
44 assert(sb1->get_allocator().get_data() == 42);
45
46 out1 << CharT('A');
47
48 static_assert(!noexcept(out1.operator=(std::move(out1)))); // LWG-3867
49 OS out2{&base2, Allocator{99}};
50
51 out2 << CharT('Z');
52
53 // Validate the data is still in the syncbuf and not in the stringbuf.
54 assert(base1.str().empty());
55 assert(base2.str().empty());
56
57 out2 = std::move(out1);
58
59 // Since sb2 is overwritten by the move its data should be in its stringbuf.
60 assert(base1.str().empty());
61 assert(base2.str().size() == 1);
62 assert(base2.str()[0] == CharT('Z'));
63
64 assert(out2.get_wrapped() == &base1);
65
66 typename OS::syncbuf_type* sb2 = out2.rdbuf();
67 assert(sb2->get_wrapped() == &base1);
68 if constexpr (std::allocator_traits<Allocator>::propagate_on_container_move_assignment::value)
69 assert(sb2->get_allocator().get_data() == 42);
70 else
71 assert(sb2->get_allocator().get_data() == 99);
72
73 assert(out1.get_wrapped() == nullptr);
74 assert(sb1->get_wrapped() == nullptr);
75
76 // The data written to 2 will be stored in sb1. The write happens after the destruction.
77 out2 << CharT('B');
78 assert(base1.str().empty());
79 }
80
81 assert(base1.str().size() == 2);
82 assert(base1.str()[0] == CharT('A'));
83 assert(base1.str()[1] == CharT('B'));
84 assert(base2.str().size() == 1);
85 assert(base2.str()[0] == CharT('Z'));
86}
87
88template <class CharT>
89static void test() {
90 test<CharT, true>();
91 test<CharT, false>();
92}
93
94int main(int, char**) {
95 test<char>();
96#ifndef TEST_HAS_NO_WIDE_CHARACTERS
97 test<wchar_t>();
98#endif
99
100 return 0;
101}
102

source code of libcxx/test/std/input.output/syncstream/osyncstream/assign.pass.cpp