7cc72a0a2e
This patch implements `std::basic_syncbuf` and `std::basic_osyncstream` as specified in paper p0053r7. ~~For ease of reviewing I am submitting this patch before submitting a patch for `std::basic_osyncstream`. ~~ ~~Please note, this patch is not 100% complete. I plan on adding more tests (see comments), specifically I plan on adding tests for multithreading and synchronization.~~ Edit: I decided that it would be far easier for me to keep track of this and make changes that affect both `std::basic_syncbuf` and `std::basic_osyncstream` if both were in one patch. The patch was originally written by @zoecarver Implements - P0053R7 - C++ Synchronized Buffered Ostream - LWG-3127 basic_osyncstream::rdbuf needs a const_cast - LWG-3334 basic_osyncstream move assignment and destruction calls basic_syncbuf::emit() twice - LWG-3570 basic_osyncstream::emit should be an unformatted output function - LWG-3867 Should std::basic_osyncstream's move assignment operator be noexcept? Reviewed By: ldionne, #libc Differential Revision: https://reviews.llvm.org/D67086
102 lines
3.0 KiB
C++
102 lines
3.0 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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// UNSUPPORTED: c++03, c++11, c++14, c++17
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// UNSUPPORTED: no-localization
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// UNSUPPORTED: libcpp-has-no-experimental-syncstream
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// <syncstream>
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// template <class charT, class traits, class Allocator>
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// class basic_osyncstream;
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// basic_osyncstream& operator=(basic_osyncstream&& rhs);
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#include <syncstream>
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#include <sstream>
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#include <cassert>
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#include "test_macros.h"
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#include "test_allocator.h"
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template <class CharT, bool propagate>
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static void test() {
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using Traits = std::char_traits<CharT>;
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using Allocator = std::conditional_t<propagate, other_allocator<CharT>, test_allocator<CharT>>;
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static_assert(std::allocator_traits<Allocator>::propagate_on_container_move_assignment::value == propagate);
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using OS = std::basic_osyncstream<CharT, Traits, Allocator>;
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std::basic_stringbuf<CharT, Traits, Allocator> base1;
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std::basic_stringbuf<CharT, Traits, Allocator> base2;
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{
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OS out1{&base1, Allocator{42}};
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assert(out1.get_wrapped() == &base1);
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typename OS::syncbuf_type* sb1 = out1.rdbuf();
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assert(sb1->get_wrapped() == &base1);
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assert(sb1->get_allocator().get_data() == 42);
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out1 << CharT('A');
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static_assert(!noexcept(out1.operator=(std::move(out1)))); // LWG-3867
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OS out2{&base2, Allocator{99}};
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out2 << CharT('Z');
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// Validate the data is still in the syncbuf and not in the stringbuf.
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assert(base1.str().empty());
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assert(base2.str().empty());
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out2 = std::move(out1);
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// Since sb2 is overwritten by the move its data should be in its stringbuf.
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assert(base1.str().empty());
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assert(base2.str().size() == 1);
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assert(base2.str()[0] == CharT('Z'));
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assert(out2.get_wrapped() == &base1);
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typename OS::syncbuf_type* sb2 = out2.rdbuf();
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assert(sb2->get_wrapped() == &base1);
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if constexpr (std::allocator_traits<Allocator>::propagate_on_container_move_assignment::value)
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assert(sb2->get_allocator().get_data() == 42);
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else
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assert(sb2->get_allocator().get_data() == 99);
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assert(out1.get_wrapped() == nullptr);
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assert(sb1->get_wrapped() == nullptr);
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// The data written to 2 will be stored in sb1. The write happens after the destruction.
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out2 << CharT('B');
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assert(base1.str().empty());
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}
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assert(base1.str().size() == 2);
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assert(base1.str()[0] == CharT('A'));
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assert(base1.str()[1] == CharT('B'));
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assert(base2.str().size() == 1);
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assert(base2.str()[0] == CharT('Z'));
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}
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template <class CharT>
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static void test() {
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test<CharT, true>();
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test<CharT, false>();
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}
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int main(int, char**) {
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test<char>();
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#ifndef TEST_HAS_NO_WIDE_CHARACTERS
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test<wchar_t>();
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#endif
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return 0;
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}
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